With the development of a new base design for hot-fillable PET containers, Krones AG in Neutraubling has been able to create a bottle with an improved temperature and pressure resistance, with a good stability and robustness during transportation. Compared to conventional hot filling, using the NitroHotfill procedure to fill such bottles allows lower bottle weights to be handled, even at high speeds. Weight savings are achieved in both the bottle's body and neck finish areas. The result is an extremely low bottle weight of just 15.5 gram for a 0.5 litre bottle.
The Contiform H used for blowing the containers is equipped with a relax-cooling sequence which is indispensable for maintaining the base stability of PET bottles during hot filling. The moulds are cooled down quickly by cooling the base mould and mould hanger with water. Using the relax-cooling procedure in conjunction with a mould temperature which is lower than that used in the conventional heatset procedure allows for the use of aluminium moulds and consequently leads to considerable cost savings. After the stretch blowing process, the bottle bases are cooled with water to stabilise them quickly before the bottles are transferred to the Modulfill filler. During subsequent hot filling using the NitroHotfill procedure with a product temperature of up to 87°C, bottle pressurisation with liquid nitrogen is directly integrated. The bottles are then cooled in a chiller and the nitrogen added during filling stops the bottle from contracting, thus making it firm and stable.
The newly developed PET container with its aesthetic and modern, understated base design is impressive thanks to its good handling and gripping qualities. It can be used with a range of different labels and contributes to energy savings. Due to the bottle's freedom of design and its shape stability, inexpensive wrap-around labelling with the Krones Contiform is also possible. With the new Nitrofill bottle from Krones, the lightweight designing of PET containers has now taken another important step forward when it comes to the hot filling of sensitive beverages.
Photo Krones AG:
A new base design for hot fillable PET containers ensures improved temperature and pressure resistance with good stability and robustness during transportation. By filling this container using the Krones NitroHotfill procedure, an extremely low bottle weight can be achieved.