Appeal No. 2000-1031
Application No. 08/591,330
substantially linear ethylene polymer prepared by “constrained
geometry catalysis.”2 (Abstract; column 3, lines 41-66.)
As to the melt flow ratio (I10/I2) and the molecular weight
distribution (Mw/Mn) of the substantially linear ethylene
polymer, Hughes teaches that the melt flow ratio (I10/I2) is
equal to or greater than 5.63, preferably from about 6.5 to 15,
and that the molecular weight distribution (Mw/Mn) is less than
or equal to I10/I2 minus 4.63, preferably between about 1.5 and
2.5. (Column line 65 to column 3, line 5.) Also, Hughes
teaches as follows:
The unique characteristic of the homogeneously
branched, substantially linear ethylene polymers is a
highly unexpected flow property where the I10/I2 value
of the polymer is essentially independent of the
polydispersity index (i.e., Mw/Mn) of the polymer.
This is contrasted with conventional linear
homogeneously branched and linear heterogeneously
branched polyethylene resins having rheological
properties such that to increase the I10/I2 value the
polydispersity index must also be increased.
2 The examiner asserts (answer, p. 3) that “constrained
geometry catalysts” are also known as “metallocene catalysts.”
In this regard, Hughes refers to U.S. Patent 5,272,236 to Lai et
al. (Lai ‘236) issued on Dec. 21, 1993 and U.S. Patent 5,278,272
to Lai et al. (Lai ‘272) issued on Jan. 11, 1994 for the method
of preparing the substantially linear ethylene polymers. (Col.
2, ll. 8-12.) Both of these patents, which are incorporated
into the disclosure of Hughes, describe the use of metallocene
catalysts.
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