The European Plastics Recyclers association EuPR has adopted the rules published last month by Petcore (PET containers recycling Europe) for the use of Mitsubishi Gas Chemical's nylon MXD-6 (polyarylamide) as a barrier layer in PET bottles. Addition of a barrier layer constitutes a contaminant in the recycled PET, and EuPR has been concerned that this contaminant should not have a negative effect on the quality of recycled bottles, particularly as it, and other barrier materials used in the past, can accumulate as material is re-used.
Petcore approved the use of MXD-6 in multilayer containers with no tie layer or adhesive for bottle-to-bottle applications up to a maximum of 2 per cent of the collected bottle stream. This followed its approval at the beginning of the year for the use of recyclate containing MXD-6 in bottle-to-fibre recycling.
The bottle-to-fibre tests involved dark mono-layer PET bottles with up to 9 per cent MXD-6 content, and concluded that R-PET containing up to 20 per cent of 91 PET:9 MXD-6 blend met fibre specifications, and as a result approved the use of dark coloured PET/MXD-6 blends for bottle-to-fibre recycling at up to 10 per cent of the bottle stream. At the time Petcore examined the use of MXD-6 in bottle-to-bottle recycling, but was unable to come to any conclusions as its tests were based on the use of coloured PET, which traditionally goes into fibres.
Now Petcore has tested clear, three-layer bottles containing around 5 per cent MXD-6 as a barrier layer and passed them for inclusion up to 2 per cent of the bottle stream. It stipulated that the preform must be injected so that the MXD6 layer is only in the bottle wall; the container must be multi-layer with no tie layers; and that there must be good air elutriation - sorting of particles in an air stream - during the recycling process.
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