polymer & packaging news agency - www.ppna.ir
New Clariant CESA-IR additive masterbatches are now available to make dark plastics visible to the NIR sensors used in automated polymer sorting systems.
While many companies use black packaging to brand products, the problems it poses in recycling systems has led to calls for black to be phased out. The new masterbatches help to resolve that issue and allows increased recycling rates in Europe and elsewhere.
Tests on HDPE also showed positive results. HDPE with CESA-IR shows a curve similar to the uncoloured HDPE curve and distinct from the LDPE curve and allowing for easy separation. PET and C-PET sheet and film were also tested by Tomra, with similarly positive results.
The new product range is part of a ‘Design for Recycling’ programme at Clariant. Recognising that recycling is the foundation of a Circular Economy, Clariant Masterbatches and its Packaging Market group, is mobilising resources across the value chain to ensure that an ever-higher percentage of plastic packaging is recycled.
NIR sensors can discriminate between HDPE, LDPE, PP, PE and various other commonly used polymers in today’s packaging. Unfortunately, the carbon black pigments typically used to make black plastics absorb all or most of the NIR light. As a result, the sorting sensors cannot ‘see’ the black packaging, much less sort one polymer from another.
Alessandro Dulli, Clariant Masterbatches Global Head of Packaging, said: “As a result of this phenomenon, much of the dark-coloured materials entering the recycling stream have not been recovered. For that reason, many brand owners have been pressured to move away from black for environmental reasons. In close collaboration with these brand companies, and as a leader in sortation technology, Clariant has developed a way to achieve a persuasive black colour in plastics without compromising the essential detectability during recycling process."
Specific CESA-IR formulations have been developed to enable IR-detectability of black HDPE and LDPE in injection and extrusion blow moulded products; black polypropylene in films and injection moulded products; and black PET and C-PET in sheets and film.
In testing conducted by Tomra Systems ASA, PP containing carbon black was essentially indistinguishable under NIR radiation from background surfaces such as a conveyor belt.
However, the same material made using another system including CESA-IR additive masterbatches was readily detectable, with reflectivity levels approaching those of uncoloured PP.
Clariant’s leaders and partners will attend the ‘Symphony of Collaboration’ K 2019 media event on 17 October at Booth 8A J11.