High molecular weight polyethylene

Patent metadata

Field	Value
Publication number	US-9428594-B2
Application number	US-201113991402-A
Country	US
Kind code	B2
Filing date	Dec 2, 2011
Priority date	Dec 3, 2010
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

The present invention pertains to a polyethylene polymer characterized by the following properties: A number average molecular weight Mn of at least 2.0*10 5 g/mol, a weight average molecular weight of at least 2.0*10 6 g/mol, a Mw/Mn ratio of above 6, and a strain hardening slope of below 0.10 N/mm at 135° C. It has been found that a polymer with these properties have be converted through solid state processing into films and fibers with good properties. A solid state processing process, films and fibers, and their use are also claimed.

First claim

The invention claimed is:

1. A polyethylene film or fiber comprising a polyethylene polymer, wherein
the film or fiber have a tensile strength of at least 1.0 GPa, a tensile modulus of at least 40 GPa, and a tensile energy-to-break of at least 15 J/g, and
the polyethylene polymer has a number average molecular weight Mn of at least 2.0*10 5 g/mol, a weight average molecular weight Mw of at least 2.0*10 6 g/mol, a Mw/Mn ratio of at least 10, and a strain hardening slope of below 0.10 N/mm at 135° C.

2. The polyethylene film or fiber according to claim 1 , wherein the polymer has a Mn in the range of 2.0-10*10 5 gram/mole.

3. The polyethylene film or fiber according to claim 1 , wherein the polymer has a Mn in the range of 2.0-8*10 5 gram/mole, in combination with a Mw/Mn of at least 15.

4. The polyethylene film or fiber according to claim 1 , wherein the polymer has an Mn of at least 800,000 g/mol and a Mw/Mn ratio between 10 and 15.

5. The polyethylene film or fiber according to claim 1 , wherein the weight average molecular weight Mw of the polymer is more than 2,000,000 g/mol.

6. The polyethylene film or fiber according to claim 1 , wherein the polymer comprises a first fraction with a Mw of at least 7 million g/mol in combination with a second fraction with a Mw of at most 1 million g/mol.

7. The polyethylene film or fiber according to claim 1 , wherein the polymer has an elastic shear modulus determined directly after melting at 160° C. of at most 1.4 MPa.

8. The polyethylene film or fiber according to claim 1 , wherein the polyethylene polymer is obtained by contacting ethylene molecules with a catalytic system under polymerization conditions for the formation of polyethylene, wherein the catalytic system contains two types of catalysts with different reaction velocities, or a catalyst is combined with two different co-catalysts.

9. The polyethylene film or fiber according to claim 8 , wherein the catalyst system comprises an activator compound and a metallocene or post-metallocene compound, wherein at least two activator compounds are used in combination.

10. A method for manufacturing the polyethylene polymer films according to claim 1 , wherein the polyethylene polymer is subjected to a compacting step and a stretching step under such conditions that at no point during the processing of the polymer is a temperature of the polymer raised to a value above a melting point of the polymer.

11. A method for manufacturing the polyethylene polymer fibers according to claim 1 , wherein the polyethylene polymer is subjected to a compacting step and a stretching step under such conditions that at no point during the processing of the polymer is a temperature of the polymer raised to a value above a melting point of the polymer, to form a film, and the film is converted into fibers.

12. The polyethylene film or fiber according to claim 1 , wherein the film has a 200/110 uniplanar orientation parameter φ of at least 3 and the fiber has a 020 uniplanar orientation parameter of at most 55°.

13. A rope, cable, net, fabric, or protective appliance comprising the polyethylene film or fiber according to claim 1 .

14. The polyethylene film or fiber according to claim 1 , wherein the polymer has a Mn in the range of 2.0-10*10 5 gram/mole, in combination with a Mw/Mn ratio of at least 15.

15. The polyethylene film or fiber according to claim 1 , wherein the polymer has a Mn in the range of 2.0-8*10 5 gram/mole, in combination with a Mw/Mn ratio of at least 20.

16. The polyethylene film or fiber according to claim 4 , wherein the polymer has an Mn of at least 1 million g/mol and a Mw/Mn ratio between 10 and 15.

17. The polyethylene film or fiber according to claim 16 , wherein the polymer has an Mn of at least 1.2 million gram/mol and a Mw/Mn ratio between 10 and 15.

18. The polyethylene film or fiber according to claim 5 , wherein the weight average molecular weight Mw of the polymer is more than 3,600,000 g/mol.

19. The polyethylene film or fiber according to claim 1 , wherein the Mw/Mn ratio is above 10.

Assignees

• Rastogi Sanjay
• Ronca Sara
• Forte Giuseppe
• Tjaden Hendrik Jacob
• Teijin Aramid Bv

Inventors

• Rastogi Sanjay
• Ronca Sara
• Forte Giuseppe
• Tjaden Hendrik Jacob

Classifications

• B29C47/0057

  Operations & Transport · mapped topic

• D01D5/00

  Formation of filaments, threads, or the like · CPC title

• C08F2500/01

  High molecular weight, e.g. >800,000 Da. · CPC title

• C08F2500/11

  Melt tension or melt strength · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title