An ethylene-propylene random copolymer of PP containing a novel clarifier (NC) was processed by 1-stage injection stretch blow molding (ISBM) and the processability and properties of the resulting bottles were evaluated and discussed as compared with polyethylene terephthalate (PET) bottles. Polypropylene (PP) with lower MFR, or higher molecular weight, processed with lower pre-form injection temperature, was found to be the key for obtaining PP bottles with excellent appearance in 1-stage ISBM. Under these conditions, NC performed as a most effective clarifier as compared with a conventional clarifier (CC), because clarifying ability of NC in lower MFR and lower injection molding temperature was superior to CC. PP bottles containing NC showed excellent heat resistance and it was found that the percentage shrinkage after autoclave sterilization was minimized. This is one of the key advantages of ISBM bottles made of PP versus PET.
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