Appeal No. 20006-0324
Application No. 10/095,154
points and softening temperatures), can be obtained by varying the molecular weight of
the polyether polyol to within the range recited in the instant claims.
We agree with the examiner that the evidence relied upon by appellants does not
overcome the prima facie case of obviousness for the following specific reasons:
First of all, we note that the data in question, in particular working examples 1
and 2 and comparative example 3, involve a variation not only of the molecular weight
of the polyether polyol, but also a variation in the amount of HDI and HDO (1, 6 -
hexanediol chain extender). Thus, the cause and effect sought to be proven is lost in a
welter of unfixed variables. In re Dunn, 349 F.2d 433, 439, 146 USPQ 479, 483 (CCPA
1965); In re Heyna, 360 F.2d 222, 228, 149 USPQ 692, 697 (CCPA 1966).
Moreover, a mere difference in results is not sufficient to establish
nonobviousness if such a difference would have been expected by those of ordinary
skill in the art. In re Freeman, 474 F.2d 1318, 1324, 177 USPQ 139, 143 (CCPA 1973).
Certainly, a variation of the molecular weight of a compositional component, or a
variation in the relative proportions of the components, would have been expected to
change the physical properties of a TPU polymer. Appellants have failed to adduce any
credible evidence that the differences in properties exemplified by the data presented in
their specification would have been unexpected by one of ordinary skill in
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