Ex parte Yokogawa

Board of Patent Appeals and Interferences

Jan 30, 1998

07916973 (B.P.A.I. Jan. 30, 1998)

Application for patent filed August 12,1992.1
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THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
Paper No. 32
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte HIROSHI YOKOGAWA, MASARU YOKOYAMA,
KOICHI TAKAHAMA and YURIKO UEGAKI
________________
Appeal No. 95-1091
Application 07/916,9731
________________
HEARD: January 13, 1998
________________
Before KIMLIN, JOHN D. SMITH and WALTZ, Administrative Patent
Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-12,
15, 16, 18 and 19. Claims 13, 20 and 21, the other claims
Appeal No. 95-1091
Application 07/916,973
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remaining in the present application, have been allowed by the
examiner. Claim 1 is illustrative of the appealed claims:
1. A process of forming a hydrophobic aerogel comprising
the steps of:
reacting a polymer having a skeleton structure of -(SiO -) 2
with a hydrophobic agent having hydrophobic groups as well as
functional groups reactive with silanol groups to obtain a
hydrophobic polymer;
dispersing said hydrophobic polymer in a dispersing medium
to form a resulting gel; and
supercritically drying said resulting gel at a temperature
and pressure above a critical point of said dispersing medium to
obtain a hydrophobic aerogel which has a porous structure.
The examiner relies upon the following references as
evidence of obviousness:
Tewari et al. (Tewari) 4,610,863 Sept. 9, 1986
Unger et al. (Unger) 4,911,903 Mar. 27, 1990
T. M. Tillotson et al. (Tillotson), "Partially Hydrolyzed
Alkoxysilanes as Precursors for Silica Aerogels," 121 Materials
Research Society Symposium Proceedings 685-689 (C. Jeffrey
Brinker et al. eds., Apr. 5-8, 1988).
Appellants' claimed invention is directed to a process for
forming a hydrophobic aerogel which finds utility in the form of
sheets for use as insulation within double glazed windows. The
process entails the conventional formation of an alcogel of a
polymer having a skeleton structure of -(SiO -) units, and using2
the known technique of converting the alcogel into a hydrophobic
aerogel having a porous structure. Appellants' departure from
Appeal No. 95-1091
Application 07/916,973
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the prior art is reacting the polymer of the alcogel with a
hydrophobic agent which replaces the silanol hydroxyl groups
existing on the surface of the polymer with hydrophobic groups.
According to appellants, the hydrophobic groups of the polymer
result in an aerogel that is less sensitive to ambient moisture
than the aerogels of the prior art, i.e., the aerogel of the
present invention maintains its transparency and dimensional
stability in humid environments.
Appealed claims 1-12, 15, 16, 18 and 19 stand rejected under
35 U.S.C. § 103 as being unpatentable over Tewari or Tillotson in
view of Unger.
We have carefully reviewed the respective positions advanced
by appellants and the examiner. In so doing, we concur with
appellants that the prior art applied by the examiner fails to
establish a prima facie case of obviousness for the claimed
subject matter. Accordingly, we will not sustain the examiner's
rejection.
The examiner recognizes that Tewari and Tillotson, the
primary references, disclose what appellants acknowledge to be
old, namely, the process of forming an aerogel by supercritically
drying a silica alcogel. The examiner also appreciates that
neither of the primary references teaches or suggests the claimed
step of reacting the silica polymer with a hydrophobic agent
Appeal No. 95-1091
Application 07/916,973
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which reacts with the silanol groups of the silica polymer. To
support the conclusion of obviousness for the claimed step not
taught by the primary references, the examiner relies upon Unger.
Unger discloses a process of forming discrete particles of
SiO which are substantially without any porosity which find2
utility as calibration standards for determining the size of
small objects and as sorption or carrier materials in the field
of chromatography and separation techniques. Unger provides
absolutely no teaching or suggestion that the product SiO2
particles, which are formed by treating a sol of primary
particles by the controlled addition of tetraalkoxysilane or
organotrialkoxysilane, which particles have virtually no
porosity, can be converted into a porous hydrophobic aerogel of
the type disclosed by the primary references and presently
claimed. In our view, the examiner has failed to factually
establish that one of ordinary skill in the art would have had a
reasonable expectation that Unger's step of forming SiO2
particles having virtually no porosity could be incorporated into
the processes of the primary references to obtain a porous
hydrophobic aerogel, let alone an aerogel having the superior
stability to moisture demonstrated in the present specification.
Accordingly, based on the foregoing, the examiner's decision
rejecting the appealed claims is reversed.
Appeal No. 95-1091
Application 07/916,973
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REVERSED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
)
JOHN D. SMITH ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
THOMAS A. WALTZ )
Administrative Patent Judge )
Appeal No. 95-1091
Application 07/916,973
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