PREPARATION OF ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE

• US 20160272738A1
• Filed: 10/24/2014
• Published: 09/22/2016
• Est. Priority Date: 10/25/2013
• Status: Active Grant

• Current Assignee: Avient Protective Materials BV (Avient Corp.)
• Original Assignee: DSM IP Assets BV (DSM-Firmenich AG)
• Inventors: SEVERN, John Richard, BERTHOUD, Romain, KIDD, Timothy James
• Granted Patent: US 9,771,440 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C08F 10/02 Ethene
• CPC Class Codes: C08F 110/02 Ethene
• CPC Class Codes: C08F 2420/03 Cp or analog not bridged to a non-Cp X ancillary neutral donor
• CPC Class Codes: C08F 2420/04 Cp or analog not bridged to a non-Cp X ancillary anionic donor
• CPC Class Codes: C08F 2500/01 High molecular weight, e.g. >800,000 Da.
• CPC Class Codes: C08F 2500/03 Narrow molecular weight distribution, i.e. Mw/Mn < 3
• CPC Class Codes: C08F 2500/17 Viscosity
• CPC Class Codes: C08F 2500/18 Bulk density
• CPC Class Codes: C08F 2500/24 Polymer with special particle form or size
• CPC Class Codes: C08F 4/65912 in combination with an organoaluminium compound
• CPC Class Codes: C08F 4/65916 supported on a carrier, e.g. silica, MgCl2, polymer
• CPC Class Codes: C08F 4/6592 containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

The invention relates to a process for the preparation of a particulate ultra high molecular weight polyethylene (UHMWPE), comprising the steps of preparing a magnesium containing carrier, loading the carrier with a organometallic compound forming a supported catalyst and contacting the supported catalyst with at least ethylene under polymerization conditions, wherein the organometallic compound is of the formula R³₃P═N—TiCpX_n.

Claims

1. Process for preparation of a particulate ultra high molecular weight polyethylene (pUHMWPE), comprising the steps of

a) preparing a magnesium containing carrier by interaction of a solution of an organomagnesium compound having composition MgR¹₂.nMgCl₂.mR²₂O where n=0.37-0.7, m=1.1-3.5, R¹ is each an aromatic or aliphatic hydrocarbyl residue and R²₂O is an aliphatic ether, with a chlorinating agent at a molar ratio Mg/Cl of at most 0.5, wherein Mg represents the Mg of the organomagnesium compound and Cl the Cl of the chlorinating agent;

b) loading the magnesium containing carrier with a organometallic compound forming a supported catalyst,

c) contacting the supported catalyst with at least ethylene under polymerization conditions,

wherein the organometallic compound is a compound of the formula R³₃P═

N—

TiCpX_n, wherein

each R³ is independently selected from the group consisting of

a hydrogen atom,

a halogen atom,

a C_1-20 hydrocarbyl radicals optionally substituted by at least one halogen atom,

a C_1-8 alkoxy radical,

a C_6-10 aryl or aryloxy radical,

an amido radical,

a silyl radical of the formula —

Si—

(R⁴)₃

and a germanyl radical of the formula —

Ge—

(R⁴)₃

wherein each R⁴ is independently selected from the group consisting of hydrogen, a C_1-8 alkyl or alkoxy radical, C_6-10 aryl or aryloxy radicals,

Cp is a cyclopentadienyl ligand;

X is an activatable ligand and n is 1 or 2, depending upon the valence of Ti and the valence of X, preferably, X is selected from the group consisting of Cl, Br, Me and Et if n=2 or X is a substituted or unsubstituted butadiene if n=1.

2. The process of claim 1 comprising the step of treating the magnesium containing carrier or the organometallic compound with an activator selected from the list of alumoxanes, alkyl aluminums, alkyl aluminum halides, anionic compounds of boron or aluminum, trialkylboron compounds, triarylboron compounds, borates, and mixtures thereof, preferably the activator is alumoxanes or alkyl aluminums.

3. The process according to claim 1 wherein the magnesium containing carrier has a D50 of 2 to 30 μ

m.

4. The process of claim 1 wherein in step c) ethylene and at least one alpha-olefin is contacted with the supported catalyst.

5. The process of claim 1 wherein the chlorinating agent is a chlorine-containing compound of composition Y_kACl_4-k, where Y=OR⁵ or R⁵ group with R⁵ being a C_1-20 hydrocarbyl radicals optionally substituted by at least one halogen atom, A being Si or C atom and k=0 to 2.

6. The process of claim 1 wherein the organometallic compound is of the formula ^tBu₃P═

N—

TiCp*X₂, wherein Cp* is pentamethylcyclopentadienyl and X is selected from the group consisting of Cl, Br, Me and Et.

7. The particulate ultrahigh molecular weight polyethylene obtainable by any of the processes according to claim 1.

8. Particulate ultra high molecular weight polyethylene (pUHMWPE) having

an intrinsic viscosity (IV) of at least 4 dl/g,

a molecular weight distribution M_w/M_n of less than 4.0,

a median particle size D50 of between 50 and 200 μ

m,

a residual Ti-content of less than 10 ppm,

a residual Si-content of less than 50 ppm, and

a total ash content of less than 1000 ppm.

9. pUHMWPE according to claim 8, wherein the polymer has an M_w/M_n of less than 3.5, preferably less than 3, most preferably less than 2.8.

10. pUHMWPE according to claim 8, wherein the polymer has an IV of at least about 8 dl/g, more preferably at least about 12 dl/g.

11. pUHMWPE according to claim 8 wherein the particulate UHMWPE has a SPAN of at most 3.

12. pUHMWPE according to claim 8 wherein the particulate UHMWPE has an apparent bulk density of at least 300 kg/m³.

13. Process for manufacturing of a molded UHMWPE articles comprising the pUHMWPE of claim 8.

14. The process according to claim 13 wherein the molded article is a fiber, tape or film.

15. A product comprising the molded articles according to claim 13, preferably the article is selected from the group consisting of ropes, cables, nets, fabrics, and protective appliances such as ballistic resistant articles.