Appeal 2006-2516
Application 10/191,449
of the effect of controlling the particle size as required by the present
invention,” since both examples are performed under identical conditions,
the only difference being the pre-sieving of the Example 1 ethylene/vinyl
alcohol copolymer to control its particle size. Id. at 4. Appellants note that
there is no detectable bisurea content in the final product of Example 1. Id.
In contrast, the final product of Comparative Example 1 contains 4 wt% of
bisurea. Id.
Appellants further rely on these examples to disprove the Examiner’s
assertion that use of a xylene solvent would yield a final product having a
low level of bisurea. Appellants point out that the solvent used in the
examples was toluene, which is similar to xylene in that it is also immiscible
with water and, therefore, would have essentially no water present in the
solvent. (Reply 2). The starting materials in the examples also underwent
the identical dehydration step of refluxing for 2 hours to remove water. Id.
According to Appellants, the difference in bisurea content in Example 1 and
Comparative Example 1 establish that the controlling parameter in reducing
bisurea by-product is not the solvent and its immiscibility with water, but the
presieving of the polymer to control particle size which provides
significantly more effective dehydration of the reaction mixture. Id.
We find Appellants’ arguments and evidence in support thereof
persuasive in establishing that control of particle size of the ethylene/vinyl
alcohol copolymer or polyvinyl alcohol in a reaction with an aliphatic
isocyanate as claimed provides an unexpected reduction of bisurea content
in the final product. The Examiner does not attempt to refute and, in fact, it
is unclear whether he has even considered (Br. 5) Appellants’ evidence of
nonobviousness. See In re Dow Chemical Co., 837 F.2d 469, 473,
4
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