Detectable black masterbatches for NIR-based polymer sorting and increased recyclability

To ensure the recyclability of black plastic products, Finke has developed a range of Fibaplast NIR detectable black masterbatches for standard packaging polymers like HDPE, PP, PS and PET. The key to recycling post-consumer waste is sorting. Common packaging polymers need to be separated to re-enter the material stream. Only pure material streams can ensure good properties and high quality of the recycling material.

Near infrared spectroscopy (NIR) has proven successful in the sorting process and has become standard technology in recycling plants. However, sorting plastic material coloured with carbon black by NIR technology can be challenging. The carbon absorbs a good part of the infrared radiation, which renders the polymer virtually “invisible” to the NIR-sorting machine and thus indistinguishable. As a result, separating different polymers like PP, HDPE, PS and PET into the correct material streams becomes difficult.

By using a carbon black-free pigment formulation for its Fibaplast NIR detectable Black Masterbatches Finke is claimed to ensure that black products become fully detectable on NIR-sorting machines. Thus, black HDPE- , PP-, PS- and PET- bottles, trays or caps can be separated easily into the correct recycling material streams using standard technology.

After successful trials conducted together with leading sorting machine manufacturers, Cotrep (Comité Technique pour la Recyclage des Emballages Plastiques) has certified Finke’s detectable Black masterbatches for rigid PE and PP packagings in October 2020. Cotrep has confirmed that products colored with the new masterbatches can be sorted by NIR technology in standard sorting facilities for post-consumer plastic packaging. Up to a concentration of 5 % masterbatch in the product, the packaging material is reliably detected and can be fed into the respective recycling stream.

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