Interference 103,482
polymers described in Ewen et al., U.S. Patent 4,892,851,
whether or not the syndiotactic polymers inherently include
occasional mistakes of three monomer units, and further
conclude that persons skilled in the art immediately would
have understood that the syndiotactic polymers the prior art
describes are not hemiisotactic polymers.
We find that the syndiotactic polymer-producing
metallocene catalysts described in Ewen et al., U.S. Patent
4,892,851, cannot be hemiisotactic polymer-producing
metallocene catalysts of the type described in Ewen, U.S.
Patent 5,036,034. Ewen et al., U.S. 4,892,851, relates at
column 12, lines 29-37 (emphasis added):
The data shown in Tables 1-4 and in FIGS. 2
and 3 show that the catalysts of the present invention
produce a predominantly syndiotactic polymer that
has high crystallinity and a novel microstructure.
Particularly, the NMR data shown in Tables 3 and 4
establish that the xylene insoluble fraction consists
of a very high percentage of syndiotactic polymer with
very little, if any, isotactic polymer being produced.
At column 13, line 67, to column 14, line 5, of U.S. Patent
4,892,851, Ewen et al. indicate that (emphasis added):
. . . similar results are obtainable through the use of
other ligands consisting of bridged Cp rings in which one
of the Cp rings is substituted in a substantially
different
manner from the other Cp ring, e.g., an indenyl radical
and a Cp ring, a tetramethyl substituted Cp ring and a
Cp ring, a dialkyl substituted Cp ring and a monoalkyl
121
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