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New developments bring lasting success in the market

Last year the Swiss moulding machine manufacturer Netstal-Maschinen AG launched several new developments on its systems for the production of PET preforms. Proof of the sustainability of these innovations had to be submitted on completion of the successful introduction. The results are now evident: outstandingly good values and processes!

Energy saving – energy reductions of up to 30% are achieved

Efforts to save energy are a mega trend also and especially in the plastics industry. Netstal identified potentials in this respect in its PET-LINE and worked on them relentlessly. Design changes concerned especially the areas of the screw drive, screw geometry, the mould closing unit and product handling equipment. Numerous measurements revealed that the novelties permit to save up to 30 percent energy at the components in question. Beyond this, Netstal focused on the entire periphery and obtained the support of the respective manufacturers. Particular attention was paid to the material drier and the raw materials. The findings now enable Netstal to optimally match the material drier and the moulding machine and to use the geometry of the PET-LINE's screw plasticizing unit yet more efficiently.

Apart from the material drier, the chiller unit holds an enormous energy saving potential as well. The moulds have been optimized in close cooperation with two mouldmaking companies. Much attention has been paid to positioning the cooling channels as near as possible to the preform's contours. This means that the cavities are cooled more intensively and the moulded parts can be taken from the mould at an earlier point in time. These measures led to an energy saving of more than 30 % in the area of the cooling unit. And on top of this the cycle times are shortened significantly!

Calitec® – the intelligent reduction of the cycle time

On moulding machines used for bulk production as in the case of preforms, the efforts to shorten the cycle time are as important as the saving of energy. The capital-intensive production equipment for preforms must be exploited as efficiently as possible. Taking this vital aspect into account, Netstal developed the innovative Calitec® system which shortens the cycle time and boosts the effects from the mould optimization described above.

Calitec® applies a slight air pressure to the inside of the preform during the aftercooling phase. This prevents the still warm preform from partly shrinking away from the cooling sleeve and thereby shortens the aftercooling phase.

With the development of Calitec® Netstal succeeds in an optimal manner to substantially reduce the cycle time. And the side-effect of a higher preform quality represents a decisive advantage for the customer.

PRElactia – mature barrier technique against the effects of UV light

Thanks to a major development effort in cooperation with the mouldmaker Molmasa and the raw material producer Novapet, both domiciled in Spain, Netstal succeeded in implementing the overmoulding process reliably, reproducibly and economically. The efficient PRElactia process permits to mould two-layer PET preforms featuring the light barrier necessary for dairy products.

PRElactia has been further developed steadily ever since its introduction. To make the light barrier more effective, the composition of the applied raw materials and of the additives fed already in the polymerization phase has been further optimized. As a result of these endeavours the originally chosen preform weight of 28 g for a 1-litre PET bottle has meanwhile come down to a mere 22 g. And this without any deterioration of the product's barrier or mechanical properties.

At last year's trade fair Emballage in Paris, furthermore, PRElactia was awarded the «Oscar de l’emballage» which underlines the value of this process once more.

Work is currently in progress to make this overmoulding process suitable also for other applications ranging from the use of recycled materials for the outer layer right to the moulding of closures in two colours or from two different materials.

There is already evidence that this novel technique will capture entirely new markets in the area of two-component moulding.