Stretching blow moulding is also called biaxial orientation
blow moulding. It is a kind of package container producing
method stretching preform in axes by mechanical device and
in radial by compressed air ( air should be cleaned by air
purifying system if necessary) when material is under high
elasticity condition. This is widely used for PET, PE, PVC
and etc.
Orientation can improve product's mechanical property, solvent
resistance, transparency and anti-permeability. Polymer molecule
is unbalanced long-chain structure. Orientation happens when
stretching. Orientation means molecule arrange along stretching
direction parallelly.
Stretching blow moulding brings biaxial orientation effect
to the products. To cool products quickly means high orientation
degree.
The glass transition temperature of PET is 82oc,
and its best orientation temperature is 105oc.
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