PETpla.net Insider 03 / 2011

PREFORM PRODUCTION 31 PET planet insider Vol. 12 No. 03/11 www.petpla.net Handling high levels of recyclate in PET preform machines Raising recyclate in preforms Sipa, the supplier of equipment for production of PET bot- tles and containers, has developed a range of solutions to produce preforms containing high levels of post-consumer recyclate in flake. Its preform injection moulding equipment designed for this function ranges from 96 down to 24 cavities. Sipa PPS Preform production systems produce preforms made with PET containing various levels of recyclate, up to 100%. The only change neces- sary to the standard configuration for handling flake at addition rates of up to 50% is the addition of an auxiliary gravimetric dryer. When recyclate content is in the 50-100% range, an upgrade to the plastification unit and filtration system is required. It is now possible to use as much as 50% recycled PET in bottles for mineral water sold in the European Union. In North America, several com- panies already produce bottles using exclusively 100% of rPET for their mineral water product. There are tight restrictions on the quality of recycled PET that can be used in new mineral water bottles. The material must be sourced from containers that were themselves approved for food contact applications. Sipa has presented the results of production on a standard-configuration PPS 72, equipped with 72 injec- tion mould cavities and fitted with a 140-mm plasticating extruder with an output of 1200 kg/h coupled to a 6000g injection pot. In all cases up to a 40:60 virgin: recyclate content, no significant problems were observed in the productivity of the standard equip- ment, nor in the quality of the preforms. Processing temperature of 280°C was set for the extruder, injection pot, hot runners and nozzles. Dimensional controls were performed on the bodies of the preforms and also on the necks. Preform weight at various levels of flake, and levels of acetaldehyde within them, were measured. No significant dimensional difference between pre- forms made with 100% virgin PET and those containing recycled PET were observed, through to 50% addition levels. Acetaldehyde levels were actu- ally seen to fall with increasing levels of recycled PET. www.sipa.com Sipa PPS preform machine detail Variation in preform colour depending on level of recyclate, from 0 to 70%. Variation in pr eform col col our our de de pen pen din din g o g o n lev lev el el of of rec rec ycl ycl ate ate , f rom rom 0 to 70%. Table 1: Acetaldehyde levels as a function of recyclate: Falls measured in intrinsic viscosity are in line with virgin PET. The visual quality of pre- forms in terms of colour, presence of impurities and burnt specks depends on the quality of the flakes used. 0 1.0 2.0 3.0 4.0 5.0 6.0 Acetaldehyde [ppm] Number of cavities 66 63 9 7 PETALO A-10% PETALO A-20% PETALO A-30% virgin PET PETALO A-40% PETALO A-50% PETALO A-60%