Extrusion blown molded bottles with high stiffness and transparency

摘要

A polypropylene composition comprising a random propylene copolymer, a high melt strength polypropylene having a branching index g′ of 0.9 or less and a clarifier, wherein the polypropylene composition has a MFR2 (230° C.) of at least 2.0 g/10 min.

主权项

1. A method for producing an extrusion blown molded product, comprising the steps of:
providing a visbroken polypropylene composition comprising a random propylene copolymer (R-PP), a high melt strength polypropylene (HMS-PP) and a clarifier, wherein (a) the R-PP comprises units derived from propylene and at least another C2 to C20 α-olefin, and has a xylene cold soluble fraction (XCS) of not more than 15.0 wt-%, (b) optionally the HMS-PP has a branching index g′ of less than 1.0, (c) the C comprises at least one α-nucleating agent clarifier, and (d) the polypropylene composition has a MFR2 (230° C.) in the range of 2.0 to 6.0 g/10 min. and a visbreaking ratio of (final MFR2 (230° C.)/initial MFR2 (230° C.)) of 1.4 to 2.5, wherein further the α-nucleating agent is selected from the group consisting of (i) C1-C8-alkyl-substituted dibenzylidenesorbitol derivatives, and (ii) vinylcycloalkane polymer and vinylalkane polymer; and
extrusion blow molding said polypropylene composition to produce an extrusion blown molded product.