Molecular weight control of gas phase polymerized polybutadiene when using a rare earth catalyst
AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorsNatarajan Muruganandam, Kevin Joseph Cann, Maria Angelica Apecetche, John Henry Moorhouse
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Abstract
A process for controlling the molecular weight (Mw) and molecular weight distribution (MWD) of polybutadiene polymerized in an otherwise gas phase process using a rare earth catalyst is provided.
Claims12
A method of controlling the molecular weight, molecular weight distribution or both of high cis-1,4-polybutadiene that is produced in a reactor in a gas phase process from 1,3-butadiene in the presence of a rare earth metal containing catalyst and at least one aluminum containing cocatalyst, which method comprises adjusting at least one of:
- (a) the temperature of the polymerization;
- (b) the butadiene partial pressure;
- (c) the concentration of cocatalyst in the product in the reactor or alternatively, the ratio of the aluminum metal of the cocatalyst to the rare earth metal of the catalyst;
- (d) selection of cocatalyst;
- and
- (e) the residence time of the rare earth catalyst in the polymerization zone of a reactor.
Dependencies are inferred from the claim text.