Machinery News

Forming bottles straight from sheet

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It is based on an innovative technology of tubular thermoforming whereby extruded plastic sheet on a reel is cut into strips and rolled around a vertical pipe to form tubular shaped strips. These are then welded together and bottles are formed by heating the tubes and blowing them into a mould at a 6 bar pressure and temperature of below 150°C.

This technology allows the production of bottles with a volume from 100 to 500 ml for use by the fresh dairy products industry, more particularly for drinking yoghurts as well as fruit juices.

The thermoforming process caters to bottles in a range of plastics (PS, PP, PLA, PET). Compared to conventional extrusion blow moulding and preform-based injection stretch blow moulding, the extruded film goes directly from the stage of sheet to bottle, this represents a savings of 30 to 50%, said Serac.

The use of reels of plastic sheet as basic material allows the reduction of the costs of transport, storage and manipulations of bottles or empty preforms upstream to the blowing.

In terms of utilities, it uses lower energy compared to the conventional technologies: the blowing is implemented at low-pressure (less 6 bar) and at low temperature (less 150°C). There is no necessity of high-pressure compressor and electric consumption is 2 to 3 times lower compared to traditional blowing of preforms.

The four-track Roll N Blow thermoforming machine, shown at the Interpack exhibition in Germany recently, had an output of 7,000 bottles/hour.