The key steps of the physico-chemical recycling process

Polyloop carries out all these operations in Batch, which ensures the qualitative separation of each batch of 300 kg processed..

  • 1
    The material to be recycled is crushed before being inserted into the process. Depending on the type of waste, upstream separation and cleaning may be necessary.
  • 2
    Batch Dissolution
    The crushed material is placed in a metal basket up to 300 kg. This patented device is inserted into the Polyloop unit like a washing machine drum. The operator chooses the recycling program. Dissolution begins, this is the first step in a STRAP process. The drum rotates and a mixture of solvent floods the reactor, specifically dissolving the PVC and the constituents of its formulation.
  • 3
    Batch Filtration and settling
    The orifices in the baskets, selected according to the type of waste, allow primary filtration by retaining the charges of the composites during draining. The charges accumulate on the inner surface of the basket and also act as a particle filter. The solvent and PVC solution is pumped through a series of ingenious filters designed not to get clogged. The filtered insolubles are then redirected to the basket.
  • 4
    Batch PVC precipitation
    Precipitation is the second step in a STRAP process: the solvent and PVC solution is placed in a reactor and heated with steam to evaporate the solvent. The solvent is gradually replaced by water in which the PVC is not soluble. By the effect of stirring, small grains of R-PVC compound form in boiling water and all of the evaporated solvent is recovered for use in another batch.
  • 5
    Batch Drying
    The wet r-PVC compound grains are dried in a very powerful dryer.

Polyloop process: the STRAP methodology

The general principle underlying the STRAP process (extraction and precipitation by targeting solvents) is:

  • Selectively dissolve a single polymer in a multi-material composite in a solvent system in which the polymer is soluble, but the other components are not.
  • The solubilized polymer is then separated from the composite by mechanical filtration and precipitated by changing the temperature and / or adding a co-solvent (an anti-solvent) that makes the dissolved polymer insoluble. The distilled solvent is reused in this process and the targeted polymer is recovered as a dry solid. This process can be repeated for each of the polymeric materials in the composite, resulting in a number of separate streams which can then be recycled.

Polyloop technology offers a STRAP process by batch “Batch STRAP”, targeting only PVC and its formulation components. The solvents which are used are reused in a closed loop.