Ex Parte Hofmann et al

Board of Patent Appeals and Interferences

Sep 10, 2009

10924119 (B.P.A.I. Sep. 10, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte JORG HOFMANN, STEPHAN EHLERS, BERND KLINKSIEK,
THORSTEN FECHTEL, MATTHIAS RUTHLAND, JURGEN SCHOLZ,
FRANZ FOHLES, and ULRICH ESSER
____________

Appeal 2009-009002
Application10/924,119
Technology Center 1600
____________

Decided: September 10, 2009
____________

Before ERIC GRIMES, LORA M. GREEN, and
RICHARD M. LEBOVITZ, Administrative Patent Judges.

LEBOVITZ, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on the Patent Applicants’ appeal from the Patent
Examiner’s rejection of claims 12-15 and 21-24 under 35 U.S.C. § 103(a).
Jurisdiction for this appeal is under 35 U.S.C. § 6(b). We affirm.

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Statement of the case
The claims are directed to a method for preparing a double-metal
cyanide (DMC) catalyst. The method comprises steps of forming a DMC
catalyst dispersion and then “filtering the double-metal cyanide catalyst
dispersion through a membrane filter press to obtain a filter cake.”
According to the Specification, DMC catalysts have been used in the prior
art to prepare polyether polyols to produce high quality polyurethanes for
elastomers, foams, and coatings (Spec. 1:1-16).
All the pending claims are appealed and stand rejected by the
Examiner as follows: claims 12-15 and 21-24 under 35 U.S.C. § 103(a) as
obvious over Le-Khac ‘428 (U.S. Patent 5,714,428, Feb. 3, 1998), Le-Khac
‘908 (U.S. Patent 5,482,908, Jan. 9, 1996), Hoch (U.S. Patent 6,103,786,
Aug. 15, 2000), Hinney (U.S. Patent 5,158,922, Oct. 27, 1992), and Heckl
(U.S. Patent 6,387,282 B1, May 14, 2002) (Ans. 31).
Appellants acknowledge that claims 12-15 and 21-24 stand or fall
together. (App. Br. 3.) Claim 12 is representative (37 C.F.R.
§ 41.31(c)(1)(vii)) and reads as follows:
12. A process for preparing a double-metal cyanide catalyst
comprising:
combining with a jet disperser in the presence of at least one organic
complexing ligand,
(a) at least one aqueous solution of at least one metal salt; with
(b) at least one aqueous solution of at least one metal cyanide
salt;
to form a double-metal cyanide catalyst dispersion;
filtering the double-metal cyanide catalyst dispersion through a
membrane filter press to obtain a filter cake;

1 The pages of the Answer were unnumbered. The page numbers referenced
in this Decision begin with the title page of the Answer numbered as page 1.
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washing the filter cake in the membrane filter press at least once with
the at least one organic complexing ligand by a flow-through washing of the
filter cake;
mechanically removing moisture in the washed filter cake; and
drying the filter cake.

Statement of the Issue
The Examiner found that Le-Khac ‘428 described all the steps of the
claimed method, but did not teach using a jet disperser or a membrane filter
press as required by claim 12 (Ans. 4-5). However, the Examiner concluded
it would have been obvious to a person of ordinary skill in the art to have
incorporated a jet disperser and membrane filter press into Le Khac’s
method based on the disclosures in the additionally cited prior art references
(id. 4-6).
Appellants did not challenge the Examiner’s prima facie case of
obviousness. Rather, they argued that a declaration by one of the inventors,
Dr. Joerg Hofmann, established that “the use of a hot filter-press in catalyst
preparations yields catalysts which have unexpectedly improved properties.”
(App. Br. 6.) The Examiner contends that the declaration is insufficient to
establish that the results were unexpected. Therefore, the issue in this appeal
is whether Appellants demonstrated that the Examiner erred in rejecting
their evidence of unexpected properties.
Principles of Law
Once prima facie obviousness has been established, an applicant for a
patent can rebut it with
a showing of “unexpected results,” i.e., to show that the
claimed invention exhibits some superior property or advantage
that a person of ordinary skill in the relevant art would have
found surprising or unexpected. The basic principle behind this
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rule is straightforward – that which would have been surprising
to a person of ordinary skill in a particular art would not have
been obvious.
In re Soni, 54 F.3d 746, 750 (Fed. Cir. 1995). “[W]hen an applicant
demonstrates substantially improved results, as Soni did here, and states that
the results were unexpected, this should suffice to establish unexpected
results in the absence of evidence to the contrary.” Id. at 751. See also In re
Geisler, 116 F.3d 1465, 1471 (Fed. Cir. 1997).
To establish unexpected results, the claimed subject matter must be
compared with the closest prior art. In re Baxter Travenol Labs., 952 F.2d
388, 392 (Fed. Cir. 1991).
Unexpected results must also be “commensurate in scope with the
degree of protection sought by the claimed subject matter.” In re Harris,
409 F.3d 1339, 1344 (Fed. Cir. 2005).

Findings of Fact
Hofmann Declaration
1. In response to the Examiner’s obviousness rejection, a declaration was
submitted by Dr. Joerg Hofmann, one of the inventors of the claimed subject
matter.
2. According to counsel, “the data presented in Dr. Hofmann’s Declaration
[established that] the use of a hot filter-press in catalyst preparation yields
catalysts which have unexpectedly improved properties.” (App. Br. 6.)
3. Dr. Hofmann testified that he had “considerable expertise in the field of
DMC [double metal cyanide] catalysis and the production of polyether
polyols” (Hofmann Dec. at 1: ¶ 3).
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4. Dr. Hofmann described experiments conducted under his “immediate
supervision and control” (Hofmann Dec. at 2: ¶ 6). These results are
described below.
5. Catalyst F was prepared with zinc chloride and potassium
hexacyanocobaltate to produce a solid dispersion. (Hofmann Dec. at 2-3.)
6. The Catalyst F solids were isolated by filtration in a “membrane filter
press.” (Id.)
7. Catalyst G, the “Comparison Example”, was prepared from the same
solid dispersion as Catalyst F, but the catalyst solids were isolated “by
filtration through a vacuum funnel.” (Hofmann Dec. at 3.)
8. Dr. Hofmann described how polyether polyols were prepared using
Catalysts F and G. (Hofmann Dec. at 3-4.)
9. Dr. Hofmann testified:
It is evident from the results that Catalyst F yields polyether
polyols having better product properties (significantly reduced
viscosity and narrower molecular weight distribution) as
compared to polyether polyols prepared with comparative
Catalyst G. As the two catalysts have been prepared from
identical starting materials, this difference must be due to the
differences in the process used for the production of the
respective catalysts.
It is evident from the results presented above that the process
for catalyst preparation as claimed in U.S. Serial Number
10/924,119 [the application involved in this appeal] yields
DMC catalysts with properties superior to those of DMC
catalysts prepared by prior art processes.
(Hofmann Dec. 5.)
10. Dr. Hofmann did not testify that the “better” and “superior” properties
would have been unexpected by a person of ordinary skill in the art.
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11. Dr. Hofmann did not testify that the isolation of Catalyst G by “filtration
through a vacuum funnel” was the same filtration method utilized by Le-
Khac ‘428 (i.e., the “prior art” method).

Le-Khac ‘428
12. The solid catalyst dispersion in Le-Khac ‘428 was “pressure filtered
through a 5 micron filter at 40 psig.” (Le-Khac ‘428, col. 8, ll. 40-41; Ans.
4).
Analysis
Because Appellants did not challenge the Examiner’s prima facie case
of obviousness, the sole issue before us is whether Appellants established
unexpected results. In making a determination about the sufficiency of
unexpected results, the PTO must consider the following factors: 1) whether
the claimed subject matter was compared to the closest prior art; 2) whether
a person of ordinary skill in the art would have found the results surprising;
and 3) whether the results are commensurate in scope with the degree of
protection sought by the claimed subject matter. With these as guiding
principles, we turn to the testimony of Dr. Hofmann in the Hofmann
declaration.
In his declaration, Dr. Hofmann focused on the step of claim 12 in
which the DMC catalyst dispersion was filtered “through a membrane filter
press to obtain a filter cake.” Catalyst F was prepared with a membrane
filter press (FF6). Catalyst G, the comparative example, was prepared using
a vacuum funnel (FF7). Polyether polyols were produced using Catalysts F
and G and their properties were compared (FF8). Dr. Hofmann concluded
that Catalyst F yielded polyether polyols “superior” and having “better
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product properties” as compared to polyether polyols prepared with
comparative Catalyst G (FF9).
As to the comparison with the closest prior art, Dr. Hofmann testified
Catalyst G was prepared by “filtration through a vacuum funnel” while
Catalyst F was prepared with a “filter press.”2 (FF6-7.) Le-Khac ‘428, cited
by the Examiner for its preparation of the same DMC catalyst described in
the declaration, pressure filtered it through a 5 micron filter (FF12). There is
no evidence that a vacuum funnel is the same as a 5 micron filter.
Dr. Hofmann did not testify that the isolation of Catalyst G by “filtration
through a vacuum funnel” was the same 5 micron filter method utilized by
Le-Khac ‘428 (i.e., the “prior art” method) (FF11). Therefore, there is
insufficient evidence that the comparison upon which the “unexpected
results” were based was with the “closest prior art.” In re Baxter Travenol
Labs., 952 F.2d at 392.
Furthermore, Dr. Hofmann did not explain how the results produced
with Catalyst F were commensurate with the scope of the claims which are
not limited to Catalyst F, but are open to any double-metal cyanide catalyst.
To establish unexpected results, it must be stated that the results
would have been surprising or unexpected to one of ordinary skill in the art.
In re Soni, 54 F.3d at 750-51. Dr. Hofmann stated that the properties of the
catalyst obtained according to the claimed process were “better” and

2 Counsel stated that the Hofmann Declaration showed that “the use of a hot
filter-press in catalyst preparation yields catalysts which have unexpectedly
improved properties.” (App. Br. 6.) However, in his declaration, Dr.
Hofmann disclosed isolating catalysts with a “membrane filter press” (FF6).
It is unclear whether Hofmann’s membrane filter press is a “hot filter-press.”
The reason for this discrepancy has not been explained.

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“superior” to prior art processes, but did not state that the superiority would
have been surprising or unexpected to one of ordinary skill in the art (FF9).

Conclusion of Law & Summary
Appellants did not provide sufficient evidence of unexpected results
to rebut the Examiner’s case of prima facie obviousness. The rejection of
claim 12 is affirmed. Claims 13-15 and 21-24 fall with claim 12 (App. Br.
3).

Time Period for Response
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

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