Hot filling of thin-walled PET bottles

WITHIN the beverage industry, the development of the HotFill+ system is nothing less than a minor revolution, allowing companies who hot fill sensitive products in PET bottles to now use PET bottles without vacuum compensation panels. 

The acclaimed father of the HotFill+ process is Rajendra Gursahaney, senior director of Engineering at the Pepsi Beverages Company, who sparked off the evolution of this efficient, sustainable and successful technology.  The trigger behind it all was that a brand of Lipton Tea without any preservatives was to be introduced to the Russian market.  Mr Gursahaney shied away from the high cost of an aseptic filling line, however, and instead opted for hot filling – under the condition that he could somehow avoid using PET bottles with vacuum compensation panels that made the bottles heavier and thus more costly.

His idea was to dose freshly filled, classic PET bottles with nitrogen to compensate for any shrinking of the PET bottles after hot filling, thus making vacuum compensation panels superfluous.  Pepsi specifications were for premium PET bottle quality coupled with a reduction in overall costs – and the highest possible stretch blow moulder output capacity. After six months of trials at the KHS Corpoplast laboratory, the desired results were achieved and the filling process has since proved itself in practice. Since the chief way of noticeably cutting costs in manufacturing PET bottles is to reduce outlays for materials, KHS Corpoplast endeavoured to considerably reduce the weight of the Lipton iced tea bottles.  This reduction proved even more advantageous than originally thought. Laboratory tests showed that it was not only possible to eliminate the need for vacuum compensation panels but also that the manufacturing process for the PET bottles could be optimised even further: blow moulds only have to be heated to a temperature of 115°C during stretch blow moulding, thus achieving considerable savings in energy.

Mr Gursahaney now looks back on two years of experience with the innovative process and is extremely satisfied that each year $2.5 million in costs for PET bottles are saved on the KHS line in Yekaterinburg, Russia, which operates on HotFill+ technology.  One reason is that the weight of a 1.5-litre PET bottle has been reduced from 63g to 48g using the new set-up.  At the same time, the environment is benefiting from a lower consumption of materials and energy.  In addition, the labelling area for the classic hot filling PET bottle can be used for marketing purposes more efficiently since absence of a vacuum panel allows better label application.

According to Mr Gursahaney, one of the decisive factors behind the success of the system was the successful collaboration with KHS during the project phase.  He sums up:  “KHS is now profiting from the great commitment that was invested in this project.  For the industry knows that in HotFill+ KHS has proved something of a pioneer – and this of course helps to boost your image no end.”

Moreover, Pepsi decided not to patent the HotFill+ process, but to share the benefits of this technology with others.  “By making a procedure that uses considerably less PET and thus less energy readily available,” says this pioneer, “we would like to do something positive for the environment and for our planet.”