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PET cups have been produced either by thin wall
injection moulding or thermoforming process so far. A new process
has been developed by Frontier Japan that uses two stage rotary
reheat stretch blow moulding to manufacture about 200-240 cups/minute
using 12 cavities in the blow moulding stage.
The advantages of enhanced clarity and higher strength as well as
barrier properties on account of orientation imparted by stretch
blow moulding process can be observed in PET cups made by this new
process.
Additionally scrap generation compared to thermoforming can be minimised.
Frontier also claims to achieve about 64% orientation in the two
stage process compared to about 50% achieved in a single stage stretch
blow moulding process. This is mainly due to the fact that 3.2x
orientation is achieved in two stage process compared to only about
2.2x in a single stage process.
The new process is already commercialized for chilled coffee. These
cups are now likely to be used for fruit and milk based products.
Frontier is now planning to develop this process for PP cups in
sizes ranging from 100-600 ml. Further development for a multilayer
cup based on PP or PET with a barrier layer of aromatic polyamide
is also a distinct possibility.
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