Blownfilm grade showing superior stiffness, transparency and processing behaviour

摘要

Extrusion blown film comprising a polypropylene composition, said polypropylene composition comprises a random propylene copolymer, a high melt strength polypropylene, a polypropylene and optionally a clarifier, wherein • the random propylene copolymer comprises units derived from propylene and at least another C₂ to C₂₀ α-olefin, • the high melt strength polypropylene has a branching index g′ of less than 1.0, the polypropylene (B) has a MFR₂ (230° C.) of at least 400 g/10 min, • the clarifier comprises at least one α-nucleating agent, and wherein further • the branching index g′ of the random propylene copolymer and the branching index g′ of the polypropylene are higher than the branching index g′ of the high melt strength polypropylene, • the random propylene copolymer has lower melt flow rate MFR₂ (230° C.) than the polypropylene, • the extrusion melt blown film and/or the polypropylene composition (i) fulfill(s) the equation (I) Tm−Tc30 (I) wherein Tm is the melting tempareture [° C.] making up more than 50% of the total melting enthalpy Hm of the extrusion melt blown film or of the polypropylene composition; Tc is the crystallization temperature [° C.] of the extrusion melt blown film or of the polypropylene composition; and/or (ii) has (have) a melt flow rate MFR₂ (230° C.) of 1.0 to 5.5 g/10 min.