Exxon Chemical Patents, Inc.

Richard R Eckman

Howard W Turner

Gregory G Hlatky

Paul Mark Henrichs

Andrew J Peacock

A method is disclosed for polymerizing olefins, diolefins, or acetylenically unsaturated monomers containing two or more carbon atoms, either alone or in combination with each other or with other polymerizable monomers, comprising contacting the monomers with an ionic polymerization catalyst comprising (1) a cation derived from a bis(cyclopentadienyl) Group IV-B metal compound by abstracting a ligand to create a positively charged species and (2) a stabilizing non-coordinating anion, said anion being sufficiently labile to permit displacement by the olefin, diolefin and/or acetylenically unsaturated monomer during polymerization. The process provides means of producing narrow molecular weight polyolefin polymers, increasing comonomer incorporation in copolymers and avoiding metal impurities in the polymer products.

Ionic metallocene catalyst compositions

Ionic catalyst compositions can be prepared by combining two components. The first component is a bis(cyclopentadienyl) Group IV-B metal complex containing at least one ligand which will combine irreversibly with the second component or at least a portion thereof such as a cation portion thereof. The second component comprises a cation which will irrevesibly react with at least one ligand on the Group IV-B metal complex and a non-coordinating anion. The combination of the two components produces an ionic catalyst composition comprising a cationic bis(cyclopentadienyl) Group IV-B metal complex which has a formal coordination number of 3 and a 4+ valence charge and the aforementioned non-coordinating anion. The anion is (i) labile and can be displaced by an olefin, diolefin or acetylenically unsaturated monomer; (ii) has a molecular diameter about or greater than 4 angstroms; (iii) forms stable salts with reducible Lewis acids and protonated Lewis bases; (iv) has a negative charge delocalized over the framework on the anion or within the core thereof; (v) is not a reducing or oxidizing agent; and (vi) is a relatively poor nucleophile. These ionic catalyst compositions can be used to polymerize .alpha.-olefins, diolefins and/or acetylenically unsaturated monomers, either alone or in combination, to polymers and copolymers.

This invention relates to syndiotactic polypropylene having greater than 55% racemic dyads having elastic characteristics at room or ambient temperature, a method for producing said syndiotactic polypropylene and articles made therefrom.

Syndiotactic polypropylene, methods for producing amorphous syndiotactic

Ionic catalyst compositions can be prepared by combining two components. The first component is a bis(cyclopentadienyl) Group IV-B metal complex containing at least one ligand which will combine irreversibly with the second component or at least a portion thereof such as a cation portion thereof. The second component comprises a cation which will irreversibly react with at least one ligand on the Group IV-B metal complex and a non-coordinating anion. The combination of the two components produces an ionic catalyst composition comprising a cationic bis(cyclopentadienyl) Group IV-B metal complex which has a formal coordination number of 3 and a 4+ valence charge and the aforementioned non-coordinating anion. The anion is (i) labile and can be displaced by an olefin, diolefin or acetylenically unsaturated monomer; (ii) has a molecular diameter about or greater than 4 angstroms; (iii) forms stable salts with reducible Lewis acids and protonated Lewis bases; (v) has a negative charge delocalized over the framework on the anion or within the core thereof; (v) is not a reducing or oxidizing agent; and (vi) is a relatively poor nucleophile. These ionic catalyst compositions can be used to polymerize .alpha.-olefins, diolefins and/or acetylenically unsaturated monomers, either alone or in combination, to polymers and copolymers.

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Houston, TX, United States of America

Richard R Eckman