Modified spray-dried Ziegler-Natta (pro)catalyst systems

Patent metadata

Field	Value
Publication number	US-11325928-B2
Application number	US-201816769271-A
Country	US
Kind code	B2
Filing date	Dec 3, 2018
Priority date	Dec 5, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A modified spray-dried Ziegler-Natta (pro)catalyst system comprising a Ziegler-Natta (pro)catalyst, a carrier material, and a tetrahydrofuran/ethanol modifier; polyolefins; methods of making and using same; and articles containing same.

First claim

The invention claimed is:

1. A modified spray-dried Ziegler-Natta procatalyst system comprising a product of spray-drying a slurry of (A+) a modified Ziegler-Natta procatalyst system and (B) a hydrophobic pre-treated fumed silica; wherein the (A+) modified Ziegler-Natta procatalyst system comprises a complex of TiCl 3 and MgCl 2 and an effective amount of (C) a tetrahydrofuran/ethanol modifier, wherein the (C) tetrahydrofuran/ethanol modifier has a THF/EtOH weight/weight ratio of from 25:75 to 75:25.

2. The modified spray-dried Ziegler-Natta procatalyst system of claim 1 further described by any one or limitations (i) to (v): (i) the titanium complex is made from TiCl 4 and Mg metal; (ii) the titanium complex is made from TiCl 3 .AA and MgCl 2 ; (iii) the (B) hydrophobic pre-treated fumed silica is a product of pre-treating an untreated fumed silica with a silicon-based hydrophobing agent; (iv) the hydrophobic pre-treated fumed silica is a product of pre-treating an untreated fumed silica with a silicon-based hydrophobing agent selected from trimethylsilyl chloride, dimethyldichlorosilane, a polydimethylsiloxane fluid, hexamethyldisilazane, an octyltrialkoxysilane, or a combination of any two or more thereof; and (v) both (ii) and (iv).

3. The modified spray-dried Ziegler-Natta procatalyst system of claim 2 wherein the silicon-based hydrophobing agent is octyltrimethoxysilane.

4. A method of making the modified spray-dried Ziegler-Natta procatalyst system of claim 1 , the method comprising spray-drying the slurry of constituents (A+) and (B) to give the modified spray-dried Ziegler-Natta procatalyst system; wherein in the slurry the (C) tetrahydrofuran/ethanol modifier has a THF/EtOH weight/weight ratio of from 25:75 to 75:25.

5. A method of reducing a modified spray-dried Ziegler-Natta catalyst system, the method comprising contacting the modified spray-dried Ziegler-Natta procatalyst system of claim 1 , with a reducing agent effective for chemically reducing a complex of TiCl 3 and MgCl 2 , thereby giving a chemically-reduced, modified spray-dried Ziegler-Natta procatalyst system.

6. A chemically-reduced, modified spray-dried Ziegler-Natta procatalyst system prepared by the method of claim 5 .

7. A method of activating a chemically-reduced, modified spray-dried Ziegler-Natta procatalyst system, the method comprising contacting the chemically-reduced, modified spray-dried Ziegler-Natta procatalyst system of claim 6 with an activator, thereby making a modified spray-dried Ziegler-Natta catalyst system.

8. A modified spray-dried Ziegler-Natta catalyst system made by the method of claim 7 .

9. A method of making a polyethylene composition, the method comprising contacting ethylene monomer and optionally zero, one, or more (C 3 -C 20 )alpha-olefin comonomers with the modified spray-dried Ziegler-Natta catalyst system of claim 8 to give a polyethylene composition comprising a polyethylene homopolymer or ethylene/(C 3 -C 20 )alpha-olefin copolymer, respectively, and the modified spray-dried Ziegler-Natta catalyst system, or a by-product thereof.

10. The method of claim 9 comprising a gas phase polymerization in the presence of molecular hydrogen gas (H 2 ) and, optionally, an induced condensing agent (ICA) in one, two or more gas phase polymerization reactors under (co)polymerizing conditions, thereby making the polyethylene composition; wherein the (co)polymerizing conditions comprise a reaction temperature from 80° C. to 110° C.; a molar ratio of the molecular hydrogen gas to the ethylene monomer (H 2 /C 2 molar ratio) from 0.001 to 0.050; and a molar ratio of the or more (C 3 -C 20 )alpha-olefin comonomers to the ethylene monomer (comonomer/C 2 molar ratio) from 0.005 to 0.10.

Assignees

• Univation Tech Llc

Inventors

• Mariott Wesley R
• Lester C Dale
• Cao Phuong A
• Awe Michael D
• Borse Nitin

Classifications

• C08F4/025

  Metal oxides · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title

• C08F2/01

  characterised by special features of the polymerisation apparatus used · CPC title

• C08F4/6555

  and magnesium or compounds thereof · CPC title

• C08F210/16 Primary

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