Univation Technologies, LLC

Exxonmobil Chemical Patents Inc.

Fred David Ehrman

Porter Clarke Shannon

Pradeep P Shirodkar

Mark Bradley Davis

Keith Wesley Trapp

David Jack Sandell

Robert Lynn Santana

Dongming Li

Chi-I Kuo

Rakesh Kumar

Marjorie E King

Michael E Muhle

Michael A Kinnan

Steven Kent Ackerman

Daniel Gerard O'Neil

G McCullough Laughlin

James Richardson Lattner

Mark Gregory Goode

Rainer Kolb

Laughlin G McCullough

Daniel Paul Zilker, Jr

Ronald Steven Eisinger

Anthony Charles Neubauer

Marc L DeChellis

Kenneth George Schurzky

Daniel P Zilker

Corrine L Brandl

Marc L De Chellis

Michele Lynn Grief-Rust

H Rodney Tunnell, Iii

David J Sandell

Steven K Ackerman

Marjorie E Mcbride

Anthony C Neubauer

Daniel G Oneil

A process including contacting one or more monomers, at least one catalyst system, and at least two condensing agents under polymerizable conditions to produce a polyolefin polymer is provided where the vapor pressure of the condensing agents is &#xb1;4 bara of the optimum vapor pressure given by the formula: optimum vapor pressure=614&#x2212;716*D+2.338*P+3.603*ln(MI), where the optimum vapor pressure has units (bara), D is the polyolefin polymer density with units (g/cc), P is the polymerization condition pressure with units (barg), and MI is the polyolefin polymer melt index with units (g/10 min). The invention also relates to a process where at least three condensing agents are used.

Polymerization process

A process including contacting one or more monomers, at least one catalyst system, and a condensing agent including a majority of 2,2-dimethylpropane under polymerizable conditions to produce a polyolefin polymer is provided.

Embodiments of our invention relate generally to methods of monitoring and controlling polymerization reactions including reactions producing multimodal polymer products using multiple catalysts in a single reactor. Embodiments of the invention provide methods of rapidly monitoring and controlling polymerization reactions without the need to sample and test the polymer properties. The method uses reactor control data and material inventory data in a mathematical leading indicator function to control the reactor conditions, and thereby the products produced under those conditions.

Polymerization monitoring and method of selecting leading indicators

Articles such as, for example, pipes or bottles, prepared from multimodal polyethylenes possessing a density from 0.940 to 0.965 g/cm, and an Ifrom 4 to 20 dg/min, and comprising a low molecular weight ethylene copolymer having a weight average molecular weight from 5,000 amu to 50,000 amu; and a high molecular weight ethylene copolymer having a weight average molecular weight from 60,000 amu to 800,000 amu, both components having a desirable balance of short chain branching making the multimodal polyethylene suitable for films, pipes, rotomolding applications and blow molding applications.

High density polyethylene and articles made therefrom

Polymerization monitoring and control using improved leading indicators

Methods of monitoring and controlling polymerization reactions are disclosed. The ratio of concentrations of two reactor components are determined in a gas stream of a reactor to obtain a leading indicator function L. The value of L or a function of L, such as a rescaled value or a reciprocal, is compared to a target value, and at least one reactor parameter is adjusted in response to a deviation between L or the function of L and the target value. Monitoring of the leading indicator permits rapid diagnosis of reactor problems, and rapid adjustments of reactor parameters, compared to laboratory analysis of samples of polymer properties.

Polymerization monitoring and control using leading indicators

Multimodal polyethylenes possessing a density from 0.940 to 0.965 g/cm, and an Ifrom 4 to 20 dg/min, and comprising a low molecular weight ethylene copolymer having a weight average molecular weight from 5,000 amu to 50,000 amu; and a high molecular weight ethylene copolymer having a weight average molecular weight from 60,000 amu to 800,000 amu, both components having a desirable balance of short chain branching making the multimodal polyethylene suitable for films, pipes, rotomolding applications and blow molding applications.

High density polyethylene

A process of producing a polyolefin, in one embodiment a polyethylene, and in a preferred embodiment a bimodal polyethylene comprising a high molecular weight component and a low molecular weight component, the process comprising providing a polyolefin having an Ivalue of from 2 to 100 g/10 min and a density of from 0.91 to 0.97 g/cm; followed by forming a melt of the polyolefin and passing the polyolefin through one or more active screen filter(s) having a mesh size of from 70 to 200 micron at a mass flux of from 5 to 100 lbs/hr/square inch; and isolating the polyolefin having passed through the screen filter.

Method of reducing gels in polyolefins

Methods of controlling the flow index and/or molecular weight split of a polymer composition are disclosed. The method of producing a polymer composition in one embodiment comprises incorporating a high molecular weight polymer into a low molecular weight polymer to form the polymer composition in a single polymerization reactor in the presence of polymerizable monomers, a bimetallic catalyst composition and at least one control agent; wherein the control agent is added in an amount sufficient to control the level of incorporation of the high molecular weight polymer, the level of low molecular weight polymer, or both. Examples of control agents include alcohols, ethers, amines and oxygen.

Polymerization process and control of polymer composition properties

A film comprising a polyethylene composition, the polyethylene composition in one embodiment comprising a high molecular weight component having a weight average molecular weight of greater than 50,000 amu and a low molecular weight component having a weight average molecular weight of less than 50,000 amu; the polyethylene composition possessing a density of between 0.940 and 0.970 g/cm, and an Ivalue of less than 20 dg/min; characterized in that the polyethylene composition extrudes at an advantageously high specific throughput at an advantageously low melt temperature, and wherein the film has a gel count of less than 100.

Polyethylene films

Films and methods of forming films comprising first combining in a reactor olefins, a catalyst composition and an activator; wherein the activator is present from less than 50 wt % in a diluent by weight of the activator and diluent; followed by isolating a polyolefin having a density of from 0.940 to 0.980 g/cm; and finally, extruding the polyolefin into a film having a gel count of less than 200 gels/m.

Methods of producing polyolefins and films therefrom

A process of producing a bimodal polyolefin composition is described, which includes in one embodiment contacting monomers with a supported bimetallic catalyst composition for a time sufficient to form a bimodal polyolefin composition that includes a high molecular weight polyolefin component and a low molecular weight polyolefin component; wherein the supported bimetallic catalyst includes a first catalyst component that is preferably non-metallocene, and a second catalyst component that includes a metallocene catalyst compound having at least one fluoride or fluorine containing leaving group, wherein the bimetallic catalyst is supported by an enhanced silica, dehydrated at a temperature of 800&#xb0; C. or more in one embodiment.

Bimodal polyolefin production process and films therefrom

Growing community of inventors

Houston, TX, United States of America

Fred David Ehrman