Injection stretch blow molding, ISBM

Injection stretch blow molding (ISBM) is an extension of injection blow molding with two modifications (a) the preform is significantly shorter than the bottle and (b) a stretch rod is used to stretch the preform in the axial direction. This process became known in the blow molding industry with the introduction of plastic or PET soft drink bottles. 

Injection vs. extrusion/blow-molding For clarity, processmg factors go hand-in-hand with the choice of a clarifier. Relatively thick-walled, injection-molded cPP homopolymer or random copolymer parts have hmits on the clarity they can achieve, perhaps down to 7%-10% haze. Only thin extruded or injection-stretch blow-molded (ISBM) cPP may achieve lower haze levels (l%-2%) that allow it to compete with PET. For one-stage ISBM of random copolymer PP, for example, newer clarifiers may work better than sorbitol-based agents... 

In blow molding, bottles or jars are produced by blowing, with air, a molten previously formed part. There are three types of blow molding extrusion blow molding (EBM), injection blow molding (IBM), and injection stretch blow molding (ISBM). 

PLA bottles are formed by injection stretch blow molding (ISBM). This process induces biaxial orientation of PLA bottle in the axial and hoop directions, which results in much improved mechanical and barrier properties compared to injection molded PLA. The molecular orientation induced during the ISBM process decreases the effect of aging by stabilizing the polymer free volume [21]. The crystallites... 

Figure 33.17 Injection stretch blow molding (ISBM).

ISBM injection stretch blow molding K Kelvin... 

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