	US 11,746,223 B2
	Process for preparing a polypropylene composition
Jingbo Wang, Linz (AT); Markus Gahleitner, Linz (AT); Elisabeth Potter, Linz (AT); Jani Aho, Porvoo (FI); Klaus Bernreitner, Linz (AT); Luc Monnissen, Arsimont (BE); and Meta Cigon, Vienna (AT)
Assigned to BOREALIS AG, Vienna (AT)
Filed by BOREALIS AG, Vienna (AT)
Filed on Jan. 25, 2022, as Appl. No. 17/583,615.
Application 17/583,615 is a continuation of application No. 16/626,095, granted, now 11,370,904, previously published as PCT/EP2018/067200, filed on Jun. 27, 2018.
Claims priority of application No. 17178731 (EP), filed on Jun. 29, 2017.
Prior Publication US 2022/0145055 A1, May 12, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C08F 2/00 (2006.01); C08F 210/06 (2006.01); C08F 4/654 (2006.01); C08L 23/14 (2006.01); C08F 10/06 (2006.01)

CPC C08L 23/14 (2013.01) [C08F 10/06 (2013.01); C08L 2205/025 (2013.01); C08L 2205/03 (2013.01); C08L 2308/00 (2013.01); C08L 2314/02 (2013.01)]

9 Claims

1. A polypropylene composition obtainable by a sequential polymerization process comprising the steps:

a) polymerizing in a first reactor monomers comprising propylene and optionally one or more comonomers selected from ethylene and C₄-C₁₀alpha-olefins, to obtain a first propylene polymer fraction having a comonomer content in the range of 0.0 to 1.8 wt %, and a MFR₂in the range of from 15.0 to 40.0 g/10 min, as measured according to ISO 1133 at 230° C. under a load of 2.16 kg;

b) polymerizing in a second reactor monomers comprising propylene and one or more comonomers selected from ethylene and C₄-C₁₀alpha-olefins, in the presence of the first propylene polymer fraction, to obtain a second propylene polymer fraction having a comonomer content in the range of 2.0 to 12.0 wt %; wherein the propylene polymer produced in the second reactor has a comonomer content in the range of 4.0 to 16.0 wt %;

c) extruding the second propylene polymer fraction in the presence of at least one alpha-nucleating agent;

wherein the process is operated in the presence of a Ziegler-Natta catalyst with a transition metal of group 4 to 6 of the periodic table and the catalyst comprising an internal donor, wherein the internal donor is a non-phthalic internal donor; and

wherein the non-phthalic internal donor is selected from (di)esters of non-phthalic carboxylic (di)acids wherein the (di)ester belongs to the group comprising malonates, maleates, citraconates, glutarates, cyclohexene-1,2-dicarboxylates, derivatives thereof, and mixtures thereof;

wherein the polypropylene composition has:

an MFR₂in the range of from 15.0 to 60.0 g/10 min, as measured according to ISO 1133 at 230° C. under a load of 2.16 kg,

a comonomer content in the range of 2.0-12.0 wt %,

a xylene soluble content (XCS) 5.6-15.0 wt %, as determined according to ISO 16152 at 25° C., and

a haze value <17.0%, as measured according to ASTM D1003 on injection moulded plaques having 1 mm thickness produced as described in EN ISO 1873-2.