Polyolefin Blends Comprising Single-Site Catalyst Produced Isotactic Polypropylene and Polyethylene, Process and Articles Made From These Blends

摘要

The invention relates to blends of at least one single-site catalyst polyethylene and at least one single-site catalyst isotactic polypropylene wherein the blend comprises an isotactic polypropylene content ranging from 25 to 55 weight percent relative to the total weight of both the polyethylene and the polypropylene contained in the blend, and wherein the at least one single-site catalyst polyethylene and the at least one single-site catalyst isotactic polypropylene are selected to fulfil the relationship:; MFI_PP=αMI2_PE  (I);with α ranging from 2.0 to 9.0, MI2_PE being the melt flow index of the polyethylene as measured according to ISO 1133 at 190° C. under a load of 2.16 kg and MFI_PP being the melt flow index of the isotactic polypropylene as measured according to ISO 1133 at 230° C. under a load of 2.16 kg. The blends show improved impact properties at both 23° C. and below 0° C. The invention is also directed to a process for producing said blends, as well as to articles produced from these blends.