Ex Parte Janssen et al

Patent Trial and Appeal Board

Jan 31, 2017

12933518 (P.T.A.B. Jan. 31, 2017)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
12/933,518 12/13/2010 Robert Hendrik Catharina Janssen BHD-4662-1666 9543
23117 7590 02/02/2017
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON, VA 22203
EXAMINER
PAPE, ZACHARY
ART UNIT PAPER NUMBER
2835
NOTIFICATION DATE DELIVERY MODE
02/02/2017 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
PTOMAIL@nixonvan.com
pair_nixon @ firsttofile. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte ROBERT HENDRIK CATHARINA JANSSEN and
FRANCISCUS VAN VEHMENDAHL
Appeal 2016-000624
Application 12/933,518
Technology Center 2800
Before LINDA M. GAUDETTE, MARK NAGUMO, and, JENNIFER R. GUPTA,
Administrative Patent Judges.
GAUDETTE, Administrative Patent Judge.
DECISION ON APPEAL
Appeal 2016-000624
Application 12/933,518
Appellants1 appeal under 35 U.S.C. § 134(a) from the Examiner’s decision2
finally rejecting claims 1—14. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
“The invention relates to a heatsink for an electrical or electronic device.”
Specification filed Sept. 20, 2010 (“Spec.”), 1:3—4. At the time of the invention, it
was known in the art to use thermally conductive plastic materials as heatsinks. Id.
at 1:12—15. According to the Specification, “[ajlthough thermally conductive
plastic materials generally combine the properties of thermal conductivity and
electrical insulation, they normally suffer in at least one of them.” Id. at 1:29—31.
The Specification further discloses that fillers added to improve one property may
have a detrimental effect on other properties of the heatsink, including mechanical
properties. See id. at 1:35—2:11. The Specification discloses, for example, that a
heatsink should have flame retarding properties, however, addition of a flame
retardant increases filler load thereby reducing the mechanical properties of the
heatsink. Id. at 2:5—10.
According to the Specification, the inventors have discovered that “heatsinks
with a plastic body made of a thermally conductive plastic material comprising at
least 20 wt.% expanded graphite showed a substantial improvement in flame
retardancy as demonstrated by a higher glow wire flammability index (GWFI). . .
without the addition of flame retardant.” Id. at 2:18—23. The Specification
discloses that although suitable thermally conductive components include
aluminum, boron nitride, graphite, etc. {id. at 7:15—17), “[t]he advantage of
expanded graphite as the thermally conductive component in the plastic
1 Appellants identity the real party in interest as DSM IP Assets, B.V. Appeal
Brief filed May 26, 2015 (“App. Br.”), 2.
2 Final Office Action mailed Feb. 24, 2015.
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Application 12/933,518
composition from which the heatsink is made is that it imparts a high thermal
conductivity already at a relatively low weight percentage, meanwhile significantly
improving the GWFI properties” (id. at 9:1—4). According to the Specification, the
composition used for making the heatsink “may be any composition having
sufficient thermal conductivity and . . . suitable for making plastic parts” (id. at
6:4—5), but is preferably a thermoplastic polymer such as a polyamide (id. at 6:21
and 26—27. The Specification further discloses that the thermoplastic polymer can
be an amorphous, a semi-crystalline, or a liquid crystal polymer. Id. at 6:21—23.
The Specification discloses that the inventive heatsink can be either electrically
conductive or electrically non-conductive “[depending on the amount of expanded
graphite and eventually depending on the type and amount of other thermally
conductive components.” Id. at 3:22—25. The Specification discloses a specific
example in which a composition comprising 70% wt.% polyamide-46 (“PA 46”)
and 30 wt.% expanded graphite achieved a passing GWFI at 960°C when tested
according to IEC-60695-2 (id. at 12:19-25), and was used to mold a heat sink
having very good electrical insulation properties (id. at 13:5—6).
Claim 1 is representative of the invention, and is reproduced below:
1. A heatsink for an electrical or electronic device comprising a
plastic body made of a thermally conductive plastic material
comprising an expanded graphite in a sufficient amount of at least
25 wt.%, relative to the total weight of the thermally conductive
plastic material, to cause the plastic body to achieve a passing glow
wire flammability index (GWFI) at 960°C when tested according to
IEC-60695-2.
App. Br. 21 (Claims App’x).
The claims stand rejected under pre-AIA 35 U.S.C. § 103(a) as follows
(Final Act. 4—9; see Examiner’s Answer mailed Aug. 12, 2015 (“Ans.”), 2
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Appeal 2016-000624
Application 12/933,518
(maintaining the Section 103 rejections as set forth in the Final Office Action, but
withdrawing the .rejections of claims 1—14 as indefinite under 35 U.S.C. § 112)):
1. Claims 1, 2, 6, and 7 over Tobita et al. (US 2004/0048054 Al,
published Mar. 11, 2004 (“Tobita”)) in view of Krassowski et al.
(US 2002/0109125 Al, published Aug. 15, 2002 (“Krassowski”)) and Joachimi et
al. (US 2003/0162900 Al, published Aug. 28, 2003 (“Joachimi”));
2. claims 3, 4, 8—12, and 14 over Tobita in view of Krassowski,
Joachimi, and Tobita et al. (US 2002/0090501 Al, published Jul. 11, 2002 (“Tobita
’501”));
3. claim 5 over Tobita in view of Krassowski, Joachimi, Tobita ’501,
and Morse (US 2008/0257585 Al, published Oct. 23, 2008); and
4. claim 13 over Tobita in view of Krassowski, Joachimi, Tobita ’501,
and Reis et al. (US 2007/0103875 Al, published May 10, 2007 (“Reis”)).
Appellants’ arguments in support of patentability are based on limitations
common to independent claims 1 and 8. See generally, App. Br. 9—20.
Appellants’ traversals of above-listed grounds of rejection 2—\ are limited to
contentions that the additional references relied on by the Examiner in support of
these rejections fail to cure the deficiencies in the combination of Tobita,
Krassowski, and Joachimi. See id. at 17—20; Ans. 7—8. Accordingly, claims 2—7
and 9-14 stand or fall with claims 1 and 8.
The Examiner relies on the following disclosures in Tobita, Krassowski, and
Joachimi in support of the obviousness rejections (see Final Act. 4—6): Tobita
describes several prior art compositions used for mounting electronic parts
comprising thermotropic liquid crystalline polymers. Tobita 1 5. In particular,
Tobita describes Japanese National Phase Laid-open Publication No. 2001-523892
as disclosing a composition comprising 80 to 20% by weight thermotropic liquid
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Appeal 2016-000624
Application 12/933,518
crystalline polymer and 20 to 80% by weight of a thermally conductive filler, such
as carbon fibers. Id. Tobita provides a list of other known thermally conductive
fillers that includes graphite. Id. 14. Krassowski discloses “a process for
providing increased electrical and/or thermal conductivity to a material” by
incorporating particles of expanded graphite into the material. Krassowski 11.
Joachimi discloses the use of polyamide compositions, including PA 46, to form
thermoplastic materials having good mechanical properties. Joachimi H 16—17.
Based on the foregoing disclosures in Tobita, Krassowski, and Joachimi, the
Examiner finds one of ordinary skill in the art would have used 20 to 80% by
weight expanded graphite as the thermally conductive filler in the known prior art
composition described in Tobita, based on Krassowski’s teaching that expanded
graphite provides increased thermal conductivity. Final Act. 4. The Examiner
further finds one of ordinary skill in the art would have replaced the 80 to 20% by
weight thermotropic liquid crystalline polymer in the composition with PA 46,
based on Joachimi’s teaching that PA 46 provides a thermoplastic material with
good mechanical/manufacturing qualities. Id. at 5. The Examiner finds the
combination would have resulted “in a heat sink which has a thermoplastic body
which is 70 wt. % PA-46 and 30 wt. % expanded graphite and thus, as per Table 1
of the present invention written description (Page 12), will pass the claimed glow
wire flammability index test.” Id.
Appellants argue the disclosure in Tobita relied on by the Examiner is a
discussion of background art, and that Tobita actually discourages the use of
thermally conductive fillers in amounts that exceed 5 wt. %. App. Br. 10—11
(citing Tobita 6 and 36). In paragraph 6, Tobita discloses that a drawback of the
prior art thermally conductive polymer compositions containing large amounts of
thermally conductive filler is that the “filler inhibits the thermotropic liquid
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Application 12/933,518
crystalline polymer from exhibiting excellent features, such as electrical insulation
properties and low density.” Tobita 1 6. In paragraph 36, Tobita discloses that
although thermal conductivity is improved when thermally conductive filler is
incorporated into the thermotropic liquid crystalline polymer, density of a molded
article made therefrom is increased, causing deterioration of electrical insulation
properties. Id. 136.
Appellants likewise argue Krassowski teaches away from including more
than 20% expanded graphite, citing Krassowski’s statement that expanded graphite
powder “should be incorporated at a level of about 1% by weight to about 20% by
weight to avoid negatively affecting the mechanical properties of the finished
substrate or material” (Krassowski 137). App. Br. 12 and 15.
Appellants acknowledge that Joachimi describes the addition of fillers and
reinforcing substances to a polyamide in amounts as high as 50%, but contend the
ordinary artisan would not have had a reasonable expectation that expanded
graphite could be added successfully to a polyamide in such high amounts. App.
Br. 16. Appellants cite the Handbook of Reinforcements for Plastics3 as evidence
that the amount of a particular filler that can be added to a thermoplastic polymer is
a function of its shape and other physical limitations. Id. at 16—17. Appellants cite
articles by Sengupta4 and George5 as evidence that one of ordinary skill in the art
3Handbook of Reinforcements for Plastics (pp. 16, 31, 44) by Van Nostrand
Reinhold Company Inc., Library of Congress Catalog Card Number 86-28255,
ISBN 0-442-26475-5 (Edition 1987).
4 Sengupta et al., A review on the mechanical and electrical properties of graphite
and modified graphite reinforced polymer composites, 36 Progress In Polymer
Science 638-670 (2011).
5 George et al., Ethylene vinyl acetate/expanded graphite nanocomposites by
solution intercalation: preparation, characterization and properties 43 J. Mater.
Sci. 702-708 (2008).
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Application 12/933,518
would have understood expanded graphite physically differs from other carbon
materials such that it could not be added as a filler to thermoplastic polymers in
amounts as high as 25%. App. Br. 13—14. Specifically, Appellants contend
Sengupta and George evidence that one of ordinary skill in the art would have
understood: expanded graphite is effective in amounts as low as 1.8 wt. %, and no
significant increase of desired properties would be expected when expanded
graphite is added in amounts above 3.5 wt. % (App. Br. 13 (citing Sengupta); see
also Reply Brief filed October 13, 2015 (“Reply Br.”), 4 ); and a “high amount” of
expanded graphite is 8 wt.%, and amounts this high have the drawback of lowering
tensile strength (App. Br. 13 (citing George); see also Reply Br. 4).
We have considered Appellants’ arguments, but do not find them persuasive
of reversible error in the Examiner’s conclusion of obviousness for the reasons
stated in the Answer. See Ans. 2—7.
Tobita discloses that, in the specific case of thermotropic liquid crystalline
polymers, the addition of filler increases density and may cause deterioration of
electrical insulation properties. Tobita 136. As argued by the Examiner, there is
no indication in Tobita that larger amounts of conductive filler would be
undesirable when a polyamide is used as the thermoplastic polymer and/or higher
electrical conductivity is a desired feature of a heat sink formed from the polymer.
Ans. 3. Moreover, Tobita clearly discloses that fillers in amounts of 20—80% have
been used successfully in thermotropic liquid crystalline compositions. Tobita 1 5;
see Ans. 4. Krassowski teaches that a significant increase in electrical and/or
thermal conductivity is provided to “molded plastic articles,” in general
(Krassowski 134; see also id. 126 (“a material or article, such as a motor vehicle
component part, a grease or oil, an adhesive or a rubber composition”)), by the
addition of expanded graphite, and that the potential for causing undesirable effects
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Application 12/933,518
by such addition, such as loss of mechanical properties, can be avoided by limiting
the amount of expanded graphite to “about 20% by weight” of the composition (id.
36—37). However, Krassowski also teaches that “higher amounts of [expanded]
graphite are feasible,” and that the amount of expanded graphite to be added to a
polymer composition “will depend on factors selected by the artisan.” Id. 136.
Thus, the Examiner had a reasonable basis for finding that when higher electrical
and/or thermal conductivity is desired, the ordinary artisan would have added
expanded graphite to the thermoplastic polymer in amounts of 25 wt.% or greater,
and had a reasonable expectation of success in so doing based on the teachings of
Tobita and Krassowski. Moreover, based on Krassowski’s teaching that addition
of expanded graphite in amounts that exceed 20% might have a negative impact on
mechanical properties (see Krassowski 136), the Examiner had a reasonable basis
for finding that the ordinary artisian would have utilized a polyamide such as
PA 46 as the thermoplastic polymer in light of Joachimi’s teaching that polyamides
“are characterized by high thermal stability, very good mechanical properties, high
toughness values, good resistance to chemicals, and easy processability,” and that
“[t]he properties of polyamides can be significantly broadened by reinforcement
with glass fibers, glass spheres, mineral fillers and mixtures thereof’ (Joachimi
12).
We have considered the teachings of Sengupta, George, and the Handbook
of Reinforcements for Plastics, but agree with the Examiner’s determination that
the totality of the evidence on this appeal record still favors a conclusion of
obviousness as to the appealed claims. See Ans. 5 (“At the very best, the Sengupta
et al. and George et al. references may teach that 25 wt. % of expanded graphite in
their composition [(e.g. poly(methyl methacrylate) and polystyrene (see Sengupta
644, Table 2), and ethylene vinyl acetate (George, Abstract))] is a large amount.”).
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Application 12/933,518
In sum, for the reasons stated in the Final Office Action, the Answer, and
above, we sustain the Examiner’s rejections of claims 1—14 under 35 U.S.C.
§ 103(a).
No time period for taking any subsequent action in connection with this
appeal may be extended under 37 C.F.R. §1.136(a)(l)(iv).
AFFIRMED
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