COLOURS AND MASTERBATCH | MATERIALS


plastics,” says Kalisvaart. “This yellowish off-colour is not widely accepted by the average consumer because it is associated with spoiled or bad product. A technical solution to the undesirable yellowish discolouration is colour neutralisation. Using opposite colourants turns the off-colour into a neutral greyish tint and allows for a wider availability of perceived higher quality material. Depending on the source and seasonable vari- ables, batch-to-batch colour consistency of recycled material can also vary. A colouring adjustment system can be set up to control colour variations within a specified range.” Tintmask is Holland Colours’ solution to address discolouration as a result of mechanical recycling of uncoloured plastics. It is available in both liquid and solid form and can be optimised to the require- ments of the customer. Holland Colours’ SORT is another example where it is working together with its customer base to develop NIR detectable colour- ants that allow for flawless sorting in separation and sorting lines. As well as these two technical solu- tions, other products are currently being developed to meet the needs of plastics recycling. Masterbatch manufacturer Broadway reports


that it has been working on the use of a PCR carrier resin to create PCR-based masterbatches. “This is particularly advantageous for any brand wishing to claim their packaging is made from 100% recycled plastic,” says James Rous, Marketing Manager. “Masterbatch typically accounts for between 1-5% of the material in the final moulding, so the carrier resin within the masterbatch needs to be a consid- eration when claiming ‘100% recycled plastic’.” Other influences in the development of colours for plastics recyclates include legislation and political influences which will determine thresholds for PCR use – such as the 30% PCR required to avoid the UK Plastic Packaging Tax. Stephen Rayner, R&D Scientist at Broadway, says that this will also affect the level and types of pigments that will be required to cover up any inherent tints of the PCR material. In addition, colour matching using PCR material often takes high levels of pigments to mask underlying colours of the PCR material itself. As such the coverage capacity of pigments needs to be considered as using more pigments counteracts the sustainable ethos associated with using PCR. He says the consistency of the colour within PCR


materials is continually being addressed at Broad- way. On-site colour matching can allow a customer to review, and if necessary, request adjustments before approving new colour matches for various batches of recycled material in a single day. Other


www.plasticsrecyclingworld.com


Above: Production facilities at Broadway in the UK


Left: Colour inspection at Broadway


important influences include developments in spectrometer technology and its software to support the rapid rematching of colours (as required) due to fluctuations of colour of PCR material, as well as legislation relating to the food contact and toy status of PCR grades. Colour tolerances permitted by moulders and


brand owners when using PCR material will also need to be addressed. “Brands will increasingly need to accept that to be environmentally friendly, they need to use high levels of PCR in their plastic packaging wherever possible,” says Rous. “This may result in imperfections or inconsistencies in colour. It would be useful to develop a culture where consumers are accustomed to these and understand the reasons for them – promoting the message that the environmental impact of packag- ing must come before aesthetics.” Broadway says that it is currently addressing a number of issues through R&D projects and technical collaborations with various organisations. These include the use of lower levels of virgin material through the use of sustainable additives, such as fillers and blowing agents, as well as the use of PCR as a masterbatch carrier. The company’s latest products include PCR-


November/December 2022 | PLASTICS RECYCLING WORLD 39


IMAGE: BROADWAY


IMAGE: BROADWAY


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50