Appeal 2007-2359
Application 90/006,951
The record shows that it is the Mg- and Si-rich aluminum alloys that
have significant coarse phases or precipitates of Mg2Si. (FF 37.) Alloys
having low Mg content, such as alloys 6 and 16, showed "negligible
amounts of such phases." (FF 38, 40.) Reiso teaches adding Mn to AlMgSi
alloys as a way to disperse or minimize the size of Mg2Si precipitates.
(FF 48–49.) Consistently, Bichsel, which Reiso cites as reporting a "positive
effect by addition of only 0.06% Mn" describes the treatment of alloys
having about 0.54 Si and 0.55 Mg. (Bichsel at 58, table at col. 1; translation
at 1; FF 50.) Thus, we find that Reiso does not generally teach that addition
of Mn to AlMgSi alloys of all compositions would have been expected to
provide beneficial extrusion properties.
The Examiner's argument that the combination of compositions that
are useful for the same purpose (Answer at 12, citing In re Kerkhoven, 626
F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980)) is not persuasive. The
"Kerkhoven rationale" is inapposite here because the question of adding two
different substances to a composition for a common purpose does not arise.
The Examiner has argued that it would have been obvious to add one
substance, Mn, to two different types aluminum alloys, namely a relatively
high Mg-alloy, and a relatively low Mg alloy. The Examiner has assumed
that the function of Mn is the same in all relevant aluminum alloys. Alcan,
however, has come forward with persuasive evidence from Reiso itself
showing that the alloys differ in the critical problem, namely the need to
minimize the size of Mg2Si precipitates. Moreover, the application of the
"Kerkhoven rationale" depends on subsidiary findings that the art of the
invention is relatively predictable and well understood. In particular, the
idea that additives known to be useful by themselves would have been
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