Appeal No. 2001-1668
Application 09/036,754
and Bennett are analogous prior art, is whether the teachings of these references are within the
field of appellants’ endeavor, or are reasonably pertinent to the particular problem which
appellants are attempting to solve. See In re Clay, 966 F.2d 656, 23 USPQ2d 1058, 1060-61
(Fed. Cir. 1992).
We cannot agree with appellants’ arguments as we find that, as the examiner points out
(answer, pages 7-8), Fleming clearly sets forth a sol/gel process of making a porous tube for
sintering and thus would be considered to prepare a “green” article or “part” by one of ordinary
skill in this art, which we determine to be clearly within the field of appellants’ endeavor. We
further agree with the examiner that Bennett is concerned with controlling gelation of a sol/gel
process utilizing silica and thus would be reasonably pertinent to the particular problem of
gelation control of a sol containing the same material which appellants address. Furthermore, we
agree with the examiner (id.) that these same teachings of the references would have lead one of
ordinary skill in this art to combine the teachings of these references with respect to the use latent
gelling agents, such as hydrolyzable esters, in order to use sol/gel processes to prepare green
pieces.
We have again carefully compared the steps of forming the sinterable porous tube from a
silica containing aqueous alkaline medium by a sol/gel process in Fleming with each of the steps
specified in appealed claim 36 in light of appellants’ arguments (brief, pages 7-8), but remain of
the opinion that this reference sets forth each of the specified steps in the order stated in the
claim. We also remain of the view that a hydrolyzable ester used to change the pH in Fleming
and taught for that purpose by Bennett, is a “chemical which is decomposable due to time
delayed, temperature sensitive reactions” as specified in appealed claim 36 because the progress
of the hydrolysis of the amount of ester in the medium is dependent in part on the temperature of
the medium. In any event, Bennett discloses that “pH adjusting agents” can “decompose
thermally” and teaches a number of such agents, which can be used in place of the hydrolyzable
ester of Fleming to change the pH of the sol/gel medium taught in Fleming.
Accordingly, based on our consideration of the totality of the record before us, we have
weighed the evidence of obviousness found in the combined teachings of Fleming and Bennett
with appellants’ countervailing evidence of and argument for nonobviousness and conclude
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