Appeal No. 2006-2485 Page 14
Application No. 10/925,646
have been obvious to a person of ordinary skill in the art to have modified the method of
Scheurman to include equivalent reducing agents such as sodium sulfite, as taught by
Waller et al., which are conventionally used for purposes of removing iron deposits.”
Examiner’s Answer, page 5.
We conclude that the examiner has set forth a prima facie case of obviousness.
Scheurman relates to the “inhibition and control of corrosion of metal surfaces in an
aqueous system.” Col. 1, lines 6-7. Scheurman teaches that “[c]orrosion generally
arises from dissolved oxygen and other chemicals attacking the iron or steel surfaces.”
Col. 1, lines 18-20. To protect the ferrous metal surfaces, Scheurman describes adding
chemicals, such as hydrazine, to chemically scavenge oxygen. Col. 1, lines 25-35. As
discussed above, we conclude that the examiner has set forth a prima facie case that
Scheurman anticipates claim 1.
To remove iron deposits from substrates, Waller describes an aqueous solution
comprising a reducing agent/oxygen scavenger, such as sodium sulphite or hydrazine.
Abstract; col. 1, lines 62-64; col. 4, lines 53-57. In addition, Waller describes including a
dispersant. Abstract; col. 4, lines 63-65. Based on these teachings, we conclude that
the examiner has set forth a prima facie case that it would have been obvious to include
sodium sulphite and dispersant in the composition of Scheurman.
Appellants argue that, while Waller teaches rust removal, it “requires HEDPA
[hydroxyethylidene diphosphonic acid] in a neutral solution. [Waller] teaches using
diethylhydroxylamine, but only as a reducing agent and even then it is added
concurrently with all of the other components of the cleaning solution.” Appeal Brief,
page 12. “It is entirely proper to point out that [a] combination of references does not
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