Leveraging pigments’ NIR reflecting properties to overcome the challenge of sorting recyclable black plastics.

Initiatives by global leading brands and governments that aim at boosting sustainability and keeping plastic within a circular economy and out of the environment are the driving forces behind the industry’s development of optimal solutions to boost sorting systems and recyclability processes.

Modern plastic recycling operations leverage high-tech processing equipment to move material at high speed with massive sorting capabilities to create the purest, least contaminated streams utilizing NIR (near infrared) signature, either in transmission or reflection.

Plastic recyclers face the challenge of accurately sorting black plastics, which are typically colored with carbon black colorants that do not reflect well in NIR sorting devices. Black polymers colored with carbon black absorb light emitted from the NIR spectrum and cannot be identified and sorted by this method, adding to the leftover stream of unsorted materials that end up in landfills.

Replacing carbon black to color food packaging with NIR reflecting pigment-based solutions that also provide the right shade and opacity whilst being approved by FDA 21 CRF 178.3297 and complying with the requirements established by EU 10/2011 regarding plastic packaging in contact with food is a major challenge for the pigments and color concentrates industry.

This paper reviews the most suitable pigment-based solutions available in the market to accomplish that goal.