David K Rohlfing

US Patent:

6384161, May 7, 2002

Filed:

Dec 30, 1999

Appl. No.:

09/474864

Inventors:

M. Bruce Welch - Bartlesville OH
David W. Dockter - Bartlesville OH
Syriac J. Palackal - Riyadh, SA
Bryan E. Hauger - Claremore OK
David C. Rohlfing - Bartlesville OK

Assignee:

Phillips Petroleum Company - Bartlesville OK

International Classification:

C08F 402

US Classification:

526129, 526114, 526119, 526160, 526943, 526153, 502103, 502107, 502110, 502117

Abstract:

The present invention provides a process for preparing a supported metallocene catalyst system that can be used to catalyze formation of polyolefins having a wide molecular weight range. In accordance with the process of the present invention, a first portion of an inorganic oxide is dried under a first set of conditions, wherein upon treatment with an organoaluminoxide and a metallocene, a first catalyst system is formed usable to produce a polyolefin product having a first molecular weight average distribution. A second portion of an inorganic oxide under a second set of conditions, wherein upon treatment with an organoaluminoxane and a metallocene, a second catalyst system is formed usable to produce polyolefin product having a second molecular weight distribution. An amount of the first portion is mixed with an amount of the second portion to produce a final inorganic oxide support. The final inorganic oxide support is combined with an organoaluminoxane and a metallocene to produce a supported metallocene catalyst system usable to catalyze formation of polyolefins with a broadened molecular weight average distribution.

US Patent:

20110035193, Feb 10, 2011

Filed:

Aug 7, 2009

Appl. No.:

12/462713

Inventors:

Paul J. Deslauriers - Owasso OK, US
David C. Rohlfing - Bartlesville OK, US

Assignee:

Chevron Phillips Chemical Company LP - The Woodlands TX

International Classification:

G06F 17/10

US Classification:

703 2

Abstract:

Systems and methods for predicting or calculating a virtual polymer property that is related to polymer architecture of a semi-crystalline polymer or calculating various virtual polymer properties related to polymer architecture as a means to design resins for particular end-use applications that require various mechanical and physical properties.

US Patent:

20130319131, Dec 5, 2013

Filed:

Oct 25, 2012

Appl. No.:

13/660747

Inventors:

Paul J. Deslauriers - Owasso OK, US
Qing Yang - Bartlesville OK, US
Ashish M. Sukhadia - Bartlesville OK, US
David C. Rohlfing - Bloomington IN, US

Assignee:

CHEVRON PHILLIPS CHEMICAL COMPANY LP - The Woodlands TX

International Classification:

G01N 3/24
G06F 17/10

US Classification:

73841, 702 43

Abstract:

A method of improving processing of polyethylene resins comprising obtaining a plurality of multimodal metallocene-catalyzed polyethylene samples measuring the shear stress as a function of shear rate for the plurality of multimodal metallocene-catalyzed polyethylene samples using capillary rheometry wherein the measuring yields values for a magnitude of slip-stick, a stress for smooth to matte transition, and a shear rate for smooth to matte transition; and identifying from the plurality of multimodal metallocene-catalyzed polyethylene samples individual multimodal metallocene-catalyzed polyethylene resins having a reduced tendency to melt fracture characterized by a magnitude of slip-stick greater than about 300 psi, a stress for smooth to matte transition greater than about 90 kPa, and a shear rate for smooth to matte transition greater than about 10 s.