US 12,071,493 B2
Polypropylene-ultrahigh-molecular-weight-polyethylene compositions
Pauli Leskinen, Porvoo (FI); Jingbo Wang, Linz (AT); Markus Gahleitner, Linz (AT); and Klaus Bernreitner, Linz (AT)
Assigned to BOREALIS AG, Vienna (AT)
Appl. No. 17/050,038
Filed by BOREALIS AG, Vienna (AT)
PCT Filed May 7, 2019, PCT No. PCT/EP2019/061646
§ 371(c)(1), (2) Date Oct. 23, 2020,
PCT Pub. No. WO2019/215125, PCT Pub. Date Nov. 14, 2019.
Claims priority of application No. 18171575 (EP), filed on May 9, 2018.
Prior Publication US 2023/0242694 A1, Aug. 3, 2023
Int. Cl. C08F 210/06 (2006.01); C08F 2/00 (2006.01); C08F 4/659 (2006.01); C08F 4/6592 (2006.01); C08F 210/02 (2006.01); C08F 210/14 (2006.01); C08L 23/16 (2006.01)
CPC C08F 210/06 (2013.01) [C08F 2/001 (2013.01); C08F 4/65912 (2013.01); C08F 4/65927 (2013.01); C08F 210/02 (2013.01); C08F 210/14 (2013.01); C08L 23/16 (2013.01); C08L 2203/18 (2013.01); C08L 2207/068 (2013.01); C08L 2314/06 (2013.01)] 9 Claims
 
1. A process for the preparation of a PP/UHMW-PE (Polypropylene-Ultrahigh-Molecular-Weight-Polyethylene) composition having:
a melting temperature Tm in the range of 125 to 150° C. (DSC, ISO 11357, Part 3),
a melt flow rate (MFR2) of 0.15 to 0.60 g/10 min (2.16 kg, 230° C., ISO1133),
units derived from 1-hexene in an amount of at least 1.80 wt. %, and
a xylene soluble content (XS) according to ISO16152 of less than 5.0 wt. %, all weight percentages with respect to the total PP/UHMW-PE composition;
wherein the process comprises the steps of:
(a) introducing a stream of propylene and 1-hexene to a first reactor, so that the molar ratio of the feed rate of 1-hexene to the feed rate of propylene is from 2.0 to 4.0 mol/kmol; further introducing a stream of a catalyst system to the first reactor, whereby the catalyst system includes:
(i) a catalyst having the following structure;

OG Complex Work Unit Chemistry
wherein;
M is zirconium or hafnium;
each X independently is a sigma-donor ligand;
L is a bridge of formula -(ER102)y-;
y is 1 or 2;
E is C or Si;
each R10 is independently a C1-C20-hydrocarbyl group, tri(C1-C20 alkyl)silyl group, C6-C20 aryl group, C7-C20 arylalkyl group or C7-C20 alkylaryl group or L is an alkylene group;
R1 are each independently the same or are different from each other and are a CH2-R11 group, with R11 being H or linear or branched C1-C6 alkyl group, C3-C8 cycloalkyl group, C6-C10 aryl group;
R3, R4 and R5 are each independently the same or different from each other and are H or a linear or branched C1-C6 alkyl group, C7-C20 arylalkyl group, C7-C20 alkylaryl group, or C6-C20 aryl group with the proviso that if there are four or more R3, R4 and R5 groups different from H present in total, one or more of R3, R4 and R5 is other than tert butyl;
R7 and R8 are each independently the same or different from each other and are H, a CH2-R12 group, with R12 being H or linear or branched C1-C6 alkyl group, SiR133, GeR133, OR13, SR13, NR132,
wherein
R13 is a linear or branched C1-C6 alkyl group, C7-C20 alkylaryl group and C7-C20 arylalkyl group or C6-C20 aryl group,
R9 are each independently the same or different from each other and are H or a linear or branched C1-C6 alkyl group; and
R2 and R6 all are H; and
(ii) a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst;
(iii) polymerizing propylene and 1-hexene in the presence of the catalyst system in the first reactor to produce a first intermediate; withdrawing a product stream comprising the first intermediate from the first reactor;
transferring the stream comprising the first intermediate to a second reactor and further polymerizing propylene in the second reactor in the presence of the first intermediate by feeding further propylene, 1-hexene and hydrogen into the second reactor such that
the molar ratio of the concentration of hydrogen to the concentration of propylene is in the range of 0.1 to 0.8 mol/kmol; and further
the molar ratio of the concentration of 1-hexene to the concentration of propylene is in the range of 4.0 to 6.0 mol/kmol
thus yielding a second intermediate and withdrawing a stream comprising the second intermediate from the second reactor
(b) transferring at least a part of the stream comprising the second intermediate to a third reactor and further polymerizing ethylene in the presence of the second intermediate by introducing ethylene into the third reactor to yield the PP/UHMW-PE (Polypropylene-Ultrahigh-Molecular-Weight-Polyethylene) composition, whereby the molar ratio of the concentration of hydrogen to the concentration of ethylene is less than 500 mol/1.0×106 mol.