Appeal No. 2006-2413 Page 12
Application No. 10/250,412
concrete or mortar can be sprayed.” Id.
“In proceedings before the Patent and Trademark Office, the Examiner bears the
burden of establishing a prima facie case of obviousness based upon the prior art. ‘[The
Examiner] can satisfy this burden only by showing some objective teaching in the prior
art or that knowledge generally available to one of ordinary skill in the art would lead
that individual to combine the relevant teachings of the references.’” In re Fritch,
972 F.2d 1260, 1265, 23 USPQ2d 1780, 1783 (Fed. Cir. 1992) (citations omitted,
bracketed material in original).
We agree with Appellant that the examiner has not established a prima facie
case of obviousness based on the cited references.
As discussed supra, Izumi ‘807 does not, in our view, disclose the limitation
requiring the cementitious mixture to contain a predominantly positively charged
polyelectrolyte, as required in each of the independent claims. As to the issue of
obviousness, the examiner has not provided specific reasons why one of ordinary skill
in the art would have added a predominantly positively charged polyelectrolyte to Izumi
807’s aqueous cementitious compositions.
We recognize that claim 3 of Izumi ‘807 (column 12, lines 56-59) recites that the
cementitious mixture can contain a thickening accelerator that “is at least one member
selected from the group consisting of an anionic, a cationic, an ampholytic and a
nonionic surfactant.” We also note that Izumi ‘807 discloses (column 4, lines 6-9) that
the surfactants used as thickening agents have a molecular weight of “at most 5,000.”
However, as cationic surfactants Izumi ‘807 lists only monomeric compounds
having a single positive charge. We do not see, and the examiner does not explain,
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