06169151 is referenced by 83 patents and cites 18 patents.

This invention relates to high melting polyolefin copolymers suitable as thermoplastic elastomers and catalysts and methods for their synthesis. These elastomeric olefin copolymers are characterized by a mole fraction of crystallizable component X

c

from about 30 to about 99%; low glass transition temperatures, below −20° C., and typically below −50° C.; melting points above about 90° C.; high molecular weights; a molecular weight distribution M

W

/M

n

</&equals;10; and a narrow composition distribution between chains of </&equals;15%. The novel copolymers of the invention range from reactor blends to multiblock copolymers that can be sequentially fractionated into fractions of differing crystallinities, which fractions nevertheless show compositions of comonomers which differ by less than 15% from the parent polymer (reactor product). The invention also relates to a process for producing such copolymers by utilizing an unbridged, substituted or unsubstituted cyclopentadienyl metallocene catalyst that is capable of interconverting between states with different copolymerization characteristics, which interconversion is controlled by selecting the substituents of the cyclopentadienyl ligands so that the rate of interconversion of the two states is within several orders of magnitude of the rate of formation of a single polymer chain. Where r

i

>r

f

the polymer can be characterized as multiblock; where r

i

<r

f

, the result is a polymer blend and where r

i

/r

f

is close to 1, the resulting polymer is a mixture of blend and multiblock. The metallocene catalysts of the invention are able to interconvert between more than two states, with embodiments of four states being shown in FIG.

2.

Title
High-melting polyolefin copolymer elastomers, catalysts and methods of synthesis
Application Number
9/227228
Publication Number
6169151 (A)
Application Date
January 8, 1999
Publication Date
January 2, 2001
Inventor
Jennifer Maciejewski Petoff
Sunnyvale
CA, US
Raisa L Kravchenko
Wilmington
DE, US
Robert M Waymouth
Palo Alto
CA, US
Agent
Innovation Law Group
US
Agent
Jacques M Dulin
US
Assignee
The Board of Trustees of the Leland Stanford Junior University
CA, US
IPC
C08F 4/44
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