From:Packaging Europe News

A new, patent pending, range of sortable colourants is set to help revolutionise the recovery of a wide variety of plastics previously undetectable by recyclers using commonly employed automated methods of identification. These plastics include rigid black plastic packaging, plastic components in end of life vehicles and WEEE waste. (Electrical & electronic waste).

IRDENT is a highly researched and WRAP tested, collection of detectable pigments from Colour Tone Masterbatch Ltd which in addition to being detectable in the waste sorting process also provide excellent colour quality.

The most common automated technology used by MRF’s (Material Recovery Facilities) and PRF’s (Plastics Recovery Facilities) for the sorting of plastics uses near infrared (NIR) spectroscopy to detect the polymer type.  These NIR detectors are capable of accurately discriminating between items made from different polymers such as PET, PP, PVC and PS. This sorting of polymers is essential to ensure that the resultant recycled material is commercially attractive to processors. However, a large amount of these potentially recyclable items cannot be identified by the NIR systems as they contain colour pigments that are very good infra-red absorbers and are therefore undetectable.

Colour Tone are confident that the use of their IRDENT range can increase the recovery of high quality materials, diverting them away from landfill and enabling them to be used in place of virgin plastic to make new products. This does not only deliver savings in CO2, but contributes to the achievement of both voluntary and legislated plastic recycling targets.

An example of a sector where this innovative technology could make a vast difference is in black plastic packaging. Typically produced from the polymers APET (amorphous Polyethylene Terephthalate), CPET (crystallised Polyethylene terephthalate), PP (Polypropylene) and PE (Polyethylene) which is traditionally coloured with carbon black pigment. This has the benefit of being low cost, providing a dense colouring, can be safely used in food contact packaging and provides a contrasting background that presents the food in an attractive manner.  The issue, however, is that plastic packaging items produced with carbon black cannot be identified with the automated sorting systems currently used in plastics recycling. Consequently, the final resting place of almost all post-consumer black plastic packaging is landfill.

Estimates suggest that there may be approximately 1 million tonnes of rigid mixed plastic packaging in the UK waste stream. Of this amount between 3-6% is considered to be black plastic packaging. In terms of tonnage, this is in the region of 26,000 - 30,000 tonnes per annum and some studies have indicated that this figure could be as high as 60,000 tonnes of black rigid plastic packaging.

Colour Tone Masterbatch Managing Director, Tony Gaukroger says “In only the example of this particular sector, the use of IRDENT in plastic packaging allows processors of black rigid plastic packaging to ensure that their products are truly recyclable, whilst still achieving a really excellent colour. We have found that processors who have already tested this are particularly satisfied with the quality of the colour. The technology required for recyclers to separate the different plastic waste streams and colours is already in use and therefore further investment would not be required. We are particularly excited at the opportunities this range presents for automotive and electrical product applications. This new generation of pigments now makes the concept of “designing for end of life” a reality and a vital part of planning for the adherence to end of life legislation. ”

The subject of extensive studies, including industrial scale manufacturing trials, by WRAP, IRDENT has been found to be useable without adversely affecting the physical properties or manufacturing process conditions.