Currently black plastic packaging is coloured using carbon black pigments which do not enable the pack to be sorted by the Near Infrared (NIR) sorting systems being used in plastics recycling. As a result, black plastic packaging commonly ends up as residue and is disposed of in landfill or recycled into lower value materials where polymer sorting is not required.
The aim of this project was to develop a solution to enable black plastic packaging to be recycled. A range of potential solutions was investigated including the use of alternative sorting technologies and alternative coloration systems. Novel NIR detectable black colorants were developed and shown to look satisfactory in APET, CPET and PP food trays, and enable the packs to be sorted by polymer using NIR sorting systems used commercially in plastics recycling.
By selecting a black pigment that would enable the polymer to be detected by NIR sorters the packaging supply chain would enable black plastic packaging to be recycled into a high quality, high value material which can substitute for virgin plastic in the manufacture of new items, and benefit the environment as well as the financial viability of mixed plastics recycling.
Further work is required to test some technical aspects of the colourants in more detail for specific product packaging ranges and to optimise them if necessary to suit particular requirements in the supply chain. WRAP encourages and supports the packaging industry including retailers, brand owners and packaging manufacturers to carry this out with a view to implementing detectable black pigments to enable the environmental benefits of recycling black plastics.