Myoung Sook Lee

US Patent:

20130090437, Apr 11, 2013

Filed:

Jun 23, 2011

Appl. No.:

13/805512

Inventors:

Parag Rasiklal Shah - Conshohocken PA, US
Yatao Rachel Hu - Malvern PA, US
Myoung Kie Lee - King of Prussia PA, US

Assignee:

PQ CORPORATION - Malvern PA

International Classification:

C08F 4/02

US Classification:

526106, 502439, 502256

Abstract:

A process for preparation of silica xerogel catalyst support particles having high surface areas involves ageing a silica hydrogel at a pH from 3 to 5 and at a temperature of 45 C. or more. The ageing at low pH leads to a silica gel which may be converted to a xerogel having a pore volume of 1.5 cm/g or more and a surface area of 600 m/g or more by removal of liquid from the pore structure by solvent exchange with a liquid solvent having a surface tension of 35 mN/m or less. The resulting particles are useful for carrying catalyst metal compounds, such as a chromium compounds, in the pore structure to act as catalyst precursors. These catalyst precursors may be activated into porous catalyst particles suitable for use for olefin polymerisation to provide high activity and for forming high molecular weight polymers (low MI polymers) with good crack resistance.

US Patent:

20210269562, Sep 2, 2021

Filed:

Feb 28, 2020

Appl. No.:

16/804610

Inventors:

Yatao Rachel HU - Malvern PA, US
Parag Rasiklal SHAH - Lafayette Hill PA, US
David George COLLOPY - Cheshire, GB
Robert Joseph PARKER - Cheshire, GB
Myoung Kie LEE - King of Prussia PA, US

International Classification:

C08F 10/02

Abstract:

A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.