Process for the preparation of an UHMWPE homopolymer

Patent metadata

Field	Value
Publication number	US-11965052-B2
Application number	US-202318111025-A
Country	US
Kind code	B2
Filing date	Feb 17, 2023
Priority date	Jul 19, 2018
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

A process for the preparation of an ultra-high molecular weight ethylene homopolymer having a MFR 21 of 0.01 g/10 min or less, said process comprising:
(I) prepolymerising at least ethylene at a temperature of 0 to 90° C. in the presence of a heterogeneous Ziegler Natta catalyst to prepare an ethylene prepolymer having an Mw of 40,000 to 600,000 g/mol; and thereafter in the presence of the prepolymer and said catalyst; (II) polymerising ethylene at a temperature of 55° C. or less, such as 20 to 55° C., to prepare said UHMW ethylene homopolymer;
wherein the UHMW ethylene homopolymer comprises up to 8 wt. % of said prepolymer.

First claim

The invention claimed is:

1. An ultra-high molecular weight ethylene homopolymer having an MFR 21 of 0.01 g/10 min or less having:
a peak melting point is 137 to 142.0° C.;
ΔH melt is 170 to 240 J/g;
a crystallinity of 60 to 80%; and
a density in the range 945 to 980 kg/m 3 .

2. An ultra-high molecular weight ethylene homopolymer as claimed in claim 1 wherein the density of the homopolymer is in the range of 955 to 975 kg/m 3 .

3. The ultra-high molecular weight (UHMW) ethylene homopolymer as claimed in claim 1 comprising:
(I) an ethylene prepolymer component having an Mw of 40,000 to 600,000 g/mol;
(II) an UHMW ethylene homopolymer component;
wherein the UHMW ethylene homopolymer comprises up to 8 wt. % of said prepolymer component.

4. An article comprising the ultra-high molecular weight ethylene homopolymer as claimed in claim 1 .

5. The article of claim 4 , wherein the article is tape.

6. An ultra-high molecular weight ethylene homopolymer having an MFR 21 of 0.01 g/10 min or less having:
a peak melting point is 137 to 142.0° C.;
ΔH melt is 170 to 240 J/g; and
a crystallinity of 60 to 80%;
wherein the ultra-high molecular weight ethylene homopolymer comprises:
(I) an ethylene prepolymer component having an Mw or 40,000 to 600,000 g/mol;
(II) an UHMW ethylene homopolymer component;

wherein the UHMW ethylene homopolymer comprises up to 8 wt. % of said prepolymer component.

7. The ultra-high molecular weight ethylene homopolymer as claimed in claim 6 wherein the density of the homopolymer is in the range of 945 to 980 kg/m 3 .

8. An ultra-high molecular weight ethylene homopolymer as claimed in claim 6 wherein the density of the homopolymer is in the range of 955 to 975 kg/m 3 .

9. An article comprising the ultra-high molecular weight ethylene homopolymer as claimed in claim 6 .

10. The article of claim 9 , wherein the article is tape.

Assignees

• Borealis Ag

Inventors

• Saeed Irfan
• Kokko Esa
• Salo Mika
• Rastogi Sanjay
• Romano Dario
• Ronca Sara

Classifications

• C08F4/6492 Primary

  containing aliphatic unsaturation · CPC title

• C08F2/001

  Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer (C08F295/00, C08F297/00 take precedence) · CPC title

• C08F4/025

  Metal oxides · CPC title

• C08F4/6546

  organo-magnesium compounds · CPC title

• C08F4/6555

  and magnesium or compounds thereof · CPC title