Heat Stabilized PET
In broad terms there are two methods for producing heat stabilized bottles, the
Single Blow and the Double Blow systems :
Single Blow
The Single Blow technique can be applied on a conventional One-Step ASB
machine. The PET container is blown inside a heated blow mold. This raises
the level of crystallinity of the PET, and also relaxes some of the stresses
induced in the PET by the stretching process so that the amount by which the
bottles shrink when hot filled is reduced.
The temperature of the mold is limited by the need to ensure that bottles
on leaving the blow mold are rigid & will not be subject to deformation. Even
using special in-mold cooling systems, "single blow" methods can only raise
service temperatures to about 83°C (after storage).