Ex Parte Iruvanti et al

Board of Patent Appeals and Interferences

Sep 4, 2002

08958848 (B.P.A.I. Sep. 4, 2002)

The opinion in support of the decision being entered today was not
written for publication and is not binding precedent of the Board.
Paper No. 21
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte SUSHUMNA IRUVANTI,
KEITH S. OLSEN,
and
KRISHNA G. SACHDEV
_____________
Appeal No. 1999-2153
Application No. 08/958,848
______________
ON BRIEF
_______________
Before GARRIS, LIEBERMAN, and DELMENDO, Administrative Patent
Judges.
GARRIS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on an appeal from the final rejection of
claims 1, 3-16, 18, 19, 21 and 22 which are all of the claims
remaining in the application.
The subject matter on appeal relates to a thermally
conductive paste having enhanced thermal conductivity and paste
properties comprising a non-aqueous dielectric liquid carrier, a
Appeal No. 1999-2153
Application No. 08/958,848
2
solid thermally conductive filler, and a dispersant which is a
polyester self-condensation reaction product of a hydroxy fatty
acid or a mixture of hydroxy fatty acids, the reaction product
having an acid no. of about 45-85. According to the appellants,
the use of a polyester self-condensation reaction product having
an acid number within the aforementioned range results in a paste
which possesses the desirable combined properties of high thermal
conductivity and relatively low paste viscosity. The appealed
subject matter also relates to a method of using such a paste and
to a method of making such a paste. This subject matter is
adequately represented by independent claim 1 which reads as
follows:
1. A thermally conductive paste having enhanced
thermal conductivity and paste properties comprising:
a non-aqueous dielectric liquid carrier;
a solid thermally conductive filler in an amount of
about 50-85% by volume of the paste dispersed in the liquid
carrier; and
a dispersant which is a polyester self-condensation
reaction product of a hydroxy fatty acid or mixture of
hydroxy fatty acids the reaction product having an Acid No.
of about 45-85 in an amount of about 1 to 10 weight % of the
paste.
Appeal No. 1999-2153
Application No. 08/958,848
3
The references relied upon by the examiner as evidence of
obviousness are:
Stansfield et al. (Stansfield) 3,778,287 Dec. 11, 1973
Iruvanti et al. (Iruvanti) 5,098,609 Mar. 24, 1992
Anderson, Jr. et al. (Anderson) 5,213,704 May 25, 1993
All of the claims on appeal stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Iruvanti in combination with
Stansfield and further in view of Anderson.
We refer to the brief and to the answer for a complete
exposition of the opposing viewpoints expressed by the appellants
and by the examiner concerning the above noted rejection.
OPINION
This rejection cannot be sustained for the reasons expressed
below.
On page 4 of the answer, the examiner expresses his
obviousness position as follows:
It would have been obvious to one of ordinary skill in the
art at the time of invention to utilize a polyester of self-
condensed 12 HSA having the instant an [sic] acid No. of
Stansfield in Iruvanti since Iruvanti teaches employing
polyesters of Stansfield and a self-condensed 12 hydroxy
stearic acid (12 HSA) and since choosing an acid No. from
the disclosed range is considered a prima facie [sic], and
Anderson, Jr. teaches mineral oils of Iruvanti as dielectric
liquid carriers.
As correctly argued by the appellants, however, the applied
references including Iruvanti and Stansfield contain no teaching
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Application No. 08/958,848
4
or suggestion of formulating a thermally conductive paste with a
polyester self-condensation reaction product having an acid no.
of any kind much less an acid no. of about 45-85 as here claimed.
We understand the examiner’s point that Iruvanti teaches
formulating his thermally conductive paste with a stabilizing
dispersant which constitutes a polyester as disclosed in
Stansfield and that Stansfield discloses polyesters generally
including “preferred polyesters having acid values in the range
of 10 to 100 mgms. KOH/gm. and especially in the range of 20 to
50 mgms. KOH/gm.” (column 2, lines 52-55). Nevertheless, we do
not share the examiner’s apparent belief that these disclosures
of Iruvanti and Stansfield would have suggested formulating
Iruvanti’s thermally conductive paste with a polyester self-
condensation reaction product having an acid no. value of about
45-85 as claimed by the appellants.
This is because, as again properly argued by the appellants,
the polyesters of Stansfield are used to prepare dispersions of
inorganic pigments in the manufacture of inks and paints (e.g.,
see the abstract). Thus, while patentee teaches formulating his
dispersions with preferred polyesters having acid no. values
which are inside as well as outside the here claimed range, there
is simply no suggestion in either Stansfield or Iruvanti of
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Application No. 08/958,848
5
formulating Iruvanti’s thermally conductive paste with polyesters
having any particular acid no. value much less the here claimed
polyester self-condensation reaction product having an acid no.
of about 45-85.
For all we know based on the record before us, an artisan
with ordinary skill would have formulated Iruvanti’s paste using
the polyesters of Stansfield without any regard whatsoever for
the acid no. value of the polyester. Certainly, it is clear that
these references contain no teaching or suggestion regarding acid
no. values of polyesters used in formulating a thermally
conductive paste. Furthermore, we discern no convincing
rationale in the answer as to why the artisan would have
formulated Iruvanti’s paste with the particular polyesters having
the particular acid no. values required by the appealed claims.
Under these circumstances, it is our determination that the
examiner has failed to carry his initial burden of establishing a
prima facie case of obviousness within the meaning of 35 U.S.C.
§ 103(a). In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d 1443,
1444 (Fed. Cir. 1992); In re Piasecki, 745 F.2d 1468, 1472, 223
USPQ 785, 787-88 (Fed. Cir. 1984). It follows that we cannot
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Application No. 08/958,848
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sustain the examiner’s Section 103 rejection of all appealed
claims as being unpatentable over Iruvanti in combination with
Stansfield and further in view of Anderson.
The decision of the examiner is reversed.
REVERSED

BRADLEY R. GARRIS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
PAUL LIEBERMAN ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
ROMULO H. DELMENDO )
Administrative Patent Judge )
BRG:hh
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Application No. 08/958,848
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