High melting thermoplastic elastomeric alpha-olefin polymers (PRE/EPE effect) and catalysts therefor

US6559262B1 · kind B1 · utility

Assignee

• The Board of Trustees of the Leland Stanford Jr. University · US

Inventors

• Robert M. Waymouth · Palo Alto, US
• Raisa Kravchenko · Wilmington, US
• Larry L. Bendig · Houston, US
• Eric J. Moore · Naperville, US
• Charles L. Myers · Palatine, US
• Roger W. Quan · Vernon Hills, US
• Andreas Ernst · Worms, DE

Key dates

• Filing date: Sep 25, 2000
• Grant date: May 6, 2003
• Expiry date: Sep 25, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S526/943
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

This invention relates generally to low ethylene insertions into I-olefin polymers and processes for production of such polymers using unbridged fluxional metallocenes, primarily substituted aryl indenyl metallocenes, and more particularly to use of unbridged, fluxional, cyclopentadienyl or indenyl metallocene catalyst systems in methods of production of high melting point I-olefin homo- and co-polymers, particularly elastomeric crystalline and amorphous block homo- and co-polymers of I-olefins. The activity of fluxional unbridged metallocene polymerization catalysts containing at least one 2-arylindene ligand is increased 10&times; or more by the addition of small (typically 0.1-10 wt. %) amounts of ethylene to the polymerization system, which increase is termed the Polymerization Rate-Enhancement effect (PRE), which is measured in terms of an Ethylene Enhancement Factor (EEF) as a dimensionless ratio in the range of from about 1.1 to about 10 or above. The amount of ethylene included in the reaction system can be selected and controlled to be so small as to result in essentially minimal (<2 mole %) incorporation of ethylene units into the resulting elastomeric polymer and the mol…