Appeal No. 2001-0106
Application 08/855,811
there simply is no probative evidence as to what happened at the interface between the
adhesive and the metal substrate.
However, we do recognize that unexpected results may still provide a basis for a
finding of nonobviousness and we turn now to consider the improved electrical
properties asserted by the Appellants.
Figure 1 of the Application illustrates that the resistance markedly increases in a
joint between a metal and a conductive adhesive, which joint has been cleaned with
isopropyl alcohol only. The resistance is generally well above 1000 mOhms. Figure 2
illustrates a similar joint, further including a vapor blast cleaning to roughen the
surfaces. The initial resistances were exceptional, but the resistance over the first 50
hours crept up significantly to a level of 1000 mOhms (excluding one sample). Figures
3 and 4, according to the invention, utilize a coating layer of organosilane, and achieve
a stabilized resistance in the vicinity of 100 mOhms.
Indeed, these are superior results. But the question remains – are they
unexpected and sufficient to overcome the rather strong prima facie case of
obviousness? The Appellants assert that “there is nothing in the art that would suggest
that these coupling agents would have any effect on electrical properties of the
conductive adhesive bond” (Appeal Brief, page 9, lines 24 – 25). Further, it is stated
that “[the coupling agents] do act in a way to prevent electrical degradation of properties
over time, which the prior art does not suggest.” (Appeal Brief, page 10, lines 1-2)
(Emphasis in Original).
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