Sipa Develops Packaging Solutions for Sustainable Future

It is now possible to use as much as 50% recycled PET in bottles for mineral water sold in the European Union.

3/8/2011 --- Sipa, has developed a full range of solutions to produce preforms containing high levels of post-consumer recyclate in flake with its preform injection moulding equipment, from 96 cavities down to 24 cavities.

Sipa is strongly committed to the development of packaging solutions for a sustainable future, be it solutions to substantially reduce the weight of packaging (eg a one-litre bottle weighing just 15 grams), or the possibility to re-use PET in flake up to 100% content.

It is now possible to use as much as 50% recycled PET in bottles for mineral water sold in the European Union. In Italy, legislation came into force last August when the government issued an update to a Ministerial Decree covering packaging, containers and utensils intended to come into contact with foodstuffs. In North America, however, several companies already produce bottles using exclusively 100% of rPET for their mineral water product.

There are of course tight restrictions on the quality of recycled PET that can be used in new mineral water bottles. In fact, the material must be sourced from containers that were themselves approved for food contact applications.

Sipa PPS Preform Production Systems successfully produce preforms made with PET containing various levels of recyclate, all the way up to 100%. In the case of flake at addition rates of up to 50 percent, the only change necessary to the standard configuration is the addition of an auxiliary gravimetric dryer. This can be considered as a minimal additional investment for an existing production unit. In the case of a content higher than 50%, and up to 100%, an upgrade to the plastification unit and filtration system is required.

As an example of the quality of preform it is possible to obtain using recyclate processed on Sipa equipment, we present the results of production on a PPS 72, equipped with 72-cavity injection moulds, fitted with a high-output 140-mm plasticating extruder with an output of 1200 kg/h coupled to a 6000-g injection pot. This is a standard configuration in Sipa’s range.

In all cases up to a ratio of 40:60 (virgin:recyclate), no significant problems are observed regarding the productivity of the standard equipment, nor with the quality of the preforms.

Processing temperature used is 280°C, which we set for the extruder, the injection pot, the hot runners and nozzles. Dimensional controls are made on the bodies of the preforms and also on the necks, as well as measuring preform weight at the various levels of flake and the levels of acetaldehyde within the preforms.

As far as the dimensions are concerned, no significant difference between preforms made with 100% virgin PET and those containing recycled PET are observed, all the way through to addition levels of 50%. Acetaldehyde levels are actually seen to fall with increasing levels of recycled PET.Falls measured in intrinsic viscosity are in line with virgin PET.

It should be pointed out that the visual quality of the preforms in terms of colour, presence of impurities and burnt specks depends entirely on the quality of the flakes used.