Sealing material of polypropylene with improved optical performance

摘要

Polypropylene composition comprising a propylene homopolymer having a melt flow rate MFR2 (230° C.) in the range of 1.0 to 20.0 g/10 min and a propylene copolymer, said copolmyer comprises •a polypropylene fraction having a comonomer content of not more than 1.0 wt.-%, the comomers are C5 to C12 α-olefins, and •a propylene copolymer fraction having a comonomer content 4.0 to 20.0 wt.-%, the comomers are C5 to C12 α-olefins, wherein further •the propylene copolymer has a comonomer content of at least 2.5 wt.-%, the comomers are C5 to C12 α-olefins, •the melt flow rate MFR2 (230° C.) of the propylene homopolymer is higher than the melt flow rate MFR2 (230° C.) of the polypropylene fraction, •the weight ratio of the polypropylene fraction to the propylene copolymer fraction is in the range of 30/70 to 70/30, and •the weight ratio of the propylene copolymer to the propylene homopolymer is in the range of 95/5 to 75/25.

主权项

1. Polypropylene composition comprising
(a) a propylene homopolymer (H-PP) having a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of 1.0 to 20.0 g/10 min, and (b) a propylene copolymer (C-PP) comprising (b-1) a polypropylene fraction (A) having a comonomer content of not more than 1.0 wt. %, the comomers are C5 to C12 α-olefins, and (b-2) a propylene copolymer fraction (B) having a comonomer content 4.0 to 20.0 wt. %, the comomers are C5 to C12 α-olefins, wherein further (c) the propylene copolymer (C-PP) has a comonomer content of at least 2.0 wt. %, the comomers are C5 to C12 α-olefins, (d) the melt flow rate MFR2 (230° C.) measured according to ISO 1133 of the propylene homopolymer (H-PP) is higher than the melt flow rate MFR2 (230° C.) measured according to ISO 1133 of the polypropylene fraction (A), (e) the weight ratio [(A)/(B)] of the polypropylene fraction (A) to the propylene copolymer fraction (B) is in the range of 30/70 to 70/30, and (f) the weight ratio [(C-PP)/(H-PP)] of the propylene copolymer (C-PP) to the propylene homopolymer(H-PP) is in the range of 95/5 to 75/25.