Polypropylene and polypropylene-elastomer blends for medical packaging

Due to the negative publicity of PVC, polypropylene is attracting increasing attention as an alternative material for flexible medical packaging. Propylene-ethylene random copolymers (PP-R) are usually the materials of choice as they are suitable for the preparation of retortable, transparent films and molded items, such as bottles and ampoules. External elastomers such as styrene-ethylene/butylene-styrene triblock-copolymers (SEBS) usually need to be added to achieve the desired softness of the final item. The influence of SEBS on the performance of PP-Rs and random-heterophasic polypropylenes (PP-R/B) were studied in detail. It was demonstrated that the toughness and the transparency of cast-films can be improved by modifying PP-Rs with SEBS (20-60 wt%). It could be shown that significantly less SEBS (∼30%) is needed for PP-R/B materials to achieve the same performance as for PP-R versions. For some cases, even the parent PP-R/B material exhibited similar properties as the PP-R-SEBS blends. These result...