Preparation of polyolefin

Patent metadata

Field	Value
Publication number	US-9540460-B2
Application number	US-201314765405-A
Country	US
Kind code	B2
Filing date	Nov 20, 2013
Priority date	Feb 7, 2013
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Catalyst systems and methods for making and using the same are provided. The catalyst systems can include a plurality of silica particles and a metallocene catalyst and an activator supported on the plurality of silica particles. The polymerization catalysts have a particle size distribution in which about 10% of the particles have a size less than about 17 to about 23 micrometers, about 50% of the particles have a size less than about 40 to about 45 micrometers, and about 90% of the particles have a size less than about 72 to about 77 micrometers.

First claim

What is claimed is:

1. A method for forming resin particles, comprising:
forming a catalyst compound comprising hafnium;
mixing the catalyst compound with an activator to form a catalyst complex; and
combining the catalyst complex with a silica support to form a supported polymerization catalyst, wherein the supported polymerization catalyst has a productivity of at least about 7000 g polymer per g catalyst;
reacting the supported polymerization catalyst with at least ethylene in a polymerization reactor to form resin particles, wherein the resin particles have:
an average polymer particle size of at least about 0.660 mm;
a size distribution of at least about 20% greater than 1 mm in diameter; and
a ratio of fluidized bulk density to settled bulk density (FBD/SBD) of at least about 0.570.

2. The method of claim 1 , wherein forming the supported polymerization catalyst includes
mixing bis(n-propylcyclopentadienyl) hafnium (CH 3 ) 2 with methylaluminoxane to form the catalyst complex; and
drying the supported catalyst to bind the catalyst complex to the silica support.

3. The method of claim 1 , further comprising adding a comonomer to the polymerization reactor to control density of the resin particles.

4. The method of claim 1 , wherein the resin particles comprise a polymer having about a 0.7 dg/min MI, about a 0.912 g/cm 3 density, and about a 26 MFR at a temperature of the polymerization reactor of at least about 77° C.

5. The method of claim 1 , wherein the resin particles comprise a polymer having about a 1 dg/min MI, about a 0.918 g/cm 3 density, and about a 28 MFR at a temperature of the polymerization reactor of at least about 75° C.

6. The method of claim 1 , further comprising adding hydrogen to the fluidized bed reactor to control a melt index of the resin particles.

7. The method of claim 1 , wherein the polymerization reactor is a fluidized bed gas phase reactor.

8. The method of claim 1 , further comprising:
measuring a sample of the resin particles to obtain an initial product property; and
changing a process parameter to obtain a second product property, based, at least in part, on the initial product property.

9. The method of claim 8 , wherein measuring a sample comprises determining a physical property of a plastic sample.

10. The method of claim 8 , wherein measuring a sample comprises determining a physical property of a plastic sample.

11. The method of claim 3 , comprising adjusting a ratio of the comonomer to ethylene within the polymerization reactor to control at least one of the composition distribution, the molecular weight distribution, and the melt index (I 2 ) of a polyethylene.

12. The method of claim 6 , comprising adjusting a ratio of the hydrogen to ethylene within the polymerization reactor to control at least one of the composition distribution, the molecular weight distribution, and the melt index (I 2 ) of a polyethylene.

Assignees

• Univation Tech Llc

Inventors

• Lester C Dale
• Cann Kevin J
• Cao Phuong A
• Hari Abarajith S
• Hussein F David
• Mariott Wesley R
• Moorhouse John H
• Pannell Richard B
• Savatsky Bruce J
• Zilker Jr Daniel P
• Goode Mark G

Classifications

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• C08F110/06

  Propene · CPC title

• C08F2500/18

  Bulk density · CPC title

• C08F10/14 Primary

  Monomers containing five or more carbon atoms · CPC title

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title