Petermann, Oliver et al.

Patent Trials and Appeals Board

Feb 27, 2020

14420911 - (D) (P.T.A.B. Feb. 27, 2020)

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.
14/420,911 02/11/2015 Oliver Petermann DI72493-US-PCT 1932
156155 7590 02/27/2020
Dow DuPont
c/o DUPONT SPECIALTY PRODUCTS USA, LLC
P.O. Box 2915
974 Centre Road, Chestnut Run Plaza 721-2342
Wilmington, DE 19805
EXAMINER
OLSON, ERIC
ART UNIT PAPER NUMBER
1623
NOTIFICATION DATE DELIVERY MODE
02/27/2020 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):
PTO-Legal.PRC@dupont.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte OLIVER PETERMANN, MATTHIAS SPREHE,
and WARREN K. MILLER
____________

Appeal 2019-003201
Application 14/420,911
Technology Center 1600
____________

Before TAWEN CHANG, TIMOTHY G. MAJORS, and
MICHAEL A. VALEK, Administrative Patent Judges.

VALEK, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 submits this appeal under 35 U.S.C. § 134(a) involving
claims to a process for preparing an esterified cellulose ether. We have
jurisdiction under 35 U.S.C. § 6(b).
We REVERSE.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. Appellant identifies Dow Global Technologies, LLC, a
wholly-owned subsidiary of The Dow Chemical Company, as the real party
in interest. Appeal Br. 3.
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Application 14/420,911

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STATEMENT OF THE CASE
“The present invention relates to an improved process for preparing an
esterified cellulose ether in the presence of an alkali metal carboxylate and
an aliphatic carboxylic acid.” Spec. 1:6–8. The Specification describes
various prior art processes for preparing esterified cellulose ethers (see id. at
1:10–4:30), but asserts that such “processes . . . are expensive in terms of
raw materials and purification procedures.” Id. at 5:1–4. The Specification
additionally explains “that controlling the weight average molecule weight
of an esterified cellulose ether is an important factor for influencing drug
release rate from solid dispersions of a drug in an esterified cellulose ether.”
Id. at 5:11–13. According to the Specification:
Surprisingly, it has been found that the weight average
molecular weight of an esterified cellulose ether can be varied
by varying the molar ratio [aliphatic carboxylic acid /
anhydroglucose units of cellulose ether] and/or varying the
molar ratio [alkali metal carboxylate / anhydroglucose units of
cellulose ether] in the process for producing the esterified
cellulose either. Even more surprisingly, it has been found that
esterified cellulose ethers having substantially the same or even
a higher weight average molecular weight as in prior art
processes can be produced even if the molar ratio [alkali metal
carboxylate / anhydroglucose units of cellulose ether] and the
molar ratio [aliphatic carboxylic acid / anhydroglucose units of
cellulose ether] are both reduced in the process for producing
the esterified cellulose ether, as compared to the specific
processes taught in the prior art.
Id. at 5:19–28.
Claims 1–6 and 9–16 are on appeal and can be found in the Claims
Appendix of the Appeal Brief. Claim 1 is representative of the claims on
appeal. It reads as follows:
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1. A process for preparing an esterified cellulose ether
wherein a cellulose ether is esterified with (i) succinic
anhydride or phthalic anhydride or with (ii) succinic anhydride
in combination with an aliphatic monocarboxylic acid
anhydride selected from the group consisting of acetic
anhydride, butyric anhydride and propionic anhydride in the
presence of an alkali metal carboxylate and an aliphatic
carboxylic acid, wherein the molar ratio [alkali metal
carboxylate / anhydroglucose units of cellulose ether] is from
[0.30 / 1] to [1.00 / 1], the molar ratio [aliphatic carboxylic acid
/ anhydroglucose units of cellulose ether] is from [3.55 / 1] to
[9.0 / 1]2 and the cellulose ether is a hydroxypropyl
methylcellulose having a viscosity of from 2.4 to 200 mPa·s,
measured as a 2 weight-% solution in water at 20°C according
to ASTM D2363 – 79 (Reapproved 2006), and the prepared
esterified cellulose ether has a weight average molecular weight
Mw of from 70,000 to 700,000 Dalton.
App. Br. 15. Appellant’s other independent claims, claims 12 and 13, recite
an alkali metal carboxylate ratio and aliphatic carboxylic acid ratio within
the same ranges as claim 1.
Appellant seeks review of Examiner’s rejection of claims 1–6 and 9–
16 under 35 U.S.C. § 103 as obvious over Onda3 in view of Cade4 and
Odidi.5 See Appeal Br. 6–18. The issue is whether the preponderance of the
evidence supports Examiner’s conclusion that the process in Appellant’s
claims is obvious over the cited prior art combination.

2 Herein, we refer to the molar ratio of alkali metal carboxylate to
anhydroglucose units of cellulose ether as the “alkali metal carboxylate
ratio” and the molar ratio of aliphatic carboxylic acid to anhydroglucose
units of cellulose ether as the “aliphatic carboxylic acid ratio.”
3 US 4,226,981, issued Oct. 7, 1980 (“Onda”).
4 WO 2008/050209 A1, published May 2, 2008 (“Cade”).
5 US 6,296,876 B1, issued Oct. 2, 2001 (“Odidi”).
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Analysis
Examiner finds that Onda Example 1 discloses a process of preparing
esterified cellulose either wherein hydroxypropyl methylcellulose
(“HPMC”) is reacted with acetic acid (corresponding to the recited
“aliphatic carboxylic acid”), sodium acetate (corresponding to the recited
“alkali metal carboxylate”), and succinic anhydride and acetic anhydride.
Final Act. 4. Examiner acknowledges that Onda does not teach the alkali
metal carboxylate ratio and aliphatic carboxylic acid ratio ranges recited in
claim 1, but determines “[c]hanges in concentrations of the components of
an old process [i.e., the process taught in Onda Example 1] do not impart
patentability unless the recited ranges are critical.” Id. at 4–5 (citing In re
Aller, 220 F.2d 454 (C.C.P.A. 1955)); see also Ans. 8 (“According to MPEP
2144.05(II)(A), optimization of a concentration . . . within prior art
conditions is obvious unless there is a showing that the concentration is
critical.”). Examiner further relies on Cade and Odidi as evidence that
HPMC with viscosity values and hydroxypropyl methylcellulose acetate
succinate with Mw values within the recited ranges were known in the art.
See id. at 5–6.
Appellant does not dispute Examiner’s finding that Onda teaches an
esterification process using the same reactant and catalyst ingredients as
claim 1, albeit at molar ratios that exceed the upper boundary of the two
recited ranges. See Appeal Br. 7–11. Instead, Appellant contends that the
use of those ingredients in amounts corresponding to the recited molar ratios
produces “a new and unexpected result” as compared to the process in Onda.
Id. at 12. Specifically, Appellant relies on evidence from WO 2014/031422
A1 (“the ’422 Publication”) showing that “when using i) only about ¼ of the
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amount of acetic acid solvent and ii) only about ¼ the amount of sodium
acetate catalyst (per mole of HPMC) taught by Onda in Example 1 . . .
comparable degrees of succinoyl substitution DOSs and acetyl substitution
DOSAc are achieved.” Id. at 12–13. According to Appellant, this result is
surprising because a skilled artisan would expect these degrees of
substitution to “be significantly reduced when the amount of catalyst is
drastically reduced, as compared to the amounts of catalyst taught in all
Examples of the Onda reference.” Id. at 13. Appellant further argues that
the higher aliphatic carboxylic acid ratio taught in Onda results in a Mw
outside the claimed 70,000 to 700,000 Dalton range (see id. at 14–15),
whereas the evidence in the ’422 Publication demonstrates “a clear trend that
the Mw increases as the [aliphatic carboxylic acid] ratio decreases” within the
recited ranges. See Reply Br. 5–7.
Upon considering the record as a whole, we determine that
Examiner’s conclusion of obviousness is not supported by the
preponderance of the evidence of record. As explained below, Appellant’s
evidence of unexpected results is sufficient to overcome Examiner’s prima
facie showing of unpatentability.
Appellant points out that all of Onda’s examples use concentrations of
reactants and catalyst that equate to substantially higher carboxylate and
carboxylic acid ratios (see Appeal Br. 7–11), but does not specifically
dispute Examiner’s determination that it would be routine to optimize those
concentrations. Moreover, Appellant does not dispute Examiner’s finding
that the recited ratio ranges “are encompassed by” and “substantially
overlap” with the broader reactant and catalyst ranges that Onda teaches, but
does not specifically exemplify. Ans. 8. Accordingly, we find no error in
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Examiner’s determination that Onda supports a prima facie case of
obviousness.
What distinguishes the present claims, however, is Appellant’s
evidence of unexpected results. Examples 10 and D–H of the ’422
Publication show the results of esterification reactions using the same
ingredients as Onda Example 1, but in different amounts. See ’422
Publication 29–30 (Tables 1 and 2). Example 10 corresponds to the process
in Appellant’s claim 1 where the “alkali metal carboxylate” catalyst (sodium
acetate) is provided at a carboxylate ratio of 0.53 and the “aliphatic
carboxylic acid” (acetic acid) is provided at a carboxylic acid ratio of 4.9.
Id. Whereas, Examples D–H use sodium acetate and acetic acid in higher
amounts corresponding to the carboxylate ratio (2.47) and carboxylic acid
ratio (16.9) in Onda Example 1. Id. As Examiner acknowledges, the “total
degree of ester substitution” for Example 10 is “similar” to that for
Examples D–H, notwithstanding the use of substantially less catalyst and
acetic acid. Ans. 9. However, based on various “observations” drawn from
the examples in the ’422 Publication, Examiner finds this result would be
“expected and well understood” to a skilled artisan. Id. at 9–10. The
problem with Examiner’s finding is that it is premised entirely on data from
the’422 Publication, which Examiner has not shown to be prior art to the
present application.6 Accordingly, Examiner has not demonstrated that

6 Appellant asserts that the ’422 Publication is not prior art because it and
the present application are commonly-owned and share the same priority
date. Appeal Br. 13. Examiner does not dispute that allegation, nor has
Examiner identified evidence to support that the data in the ’422 Publication
would have otherwise been known to one of ordinary skill in the art as of the
priority date of the present application.
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Appellant’s evidence showing that a similar degree of esterification can be
achieved with “dramatically reduced raw material utilization” would have
been expected from the prior art. See Appeal Br. 13–14.
In addition, the data from the ’422 Publication supports Appellant’s
argument that the recited molar ratio ranges are critical because they result
in an esterified cellulose ether with a higher Mw than those produced by the
process taught in Onda Example 1. See Appeal Br. 14–15. The Mw of the
esterified HPMC in Example 10 of the ’422 Publication is 142 kDA. ’429
Publication 30 (Table 2). In contrast, the Mw for Examples D–H (which
correspond to the molar ratios in Onda Example 1) range from 36–41 kDa
and are, therefore, outside the “70,000 to 700,000 Dalton” range recited in
Appellant’s claims. In addition, we agree with Appellant that the data in the
’422 Publication evidences a “trend that the Mw increases as the [aliphatic
carboxylic acid] ratio decreases,” whereas “Mw decreases as the [alkali metal
carboxylate] ratio decreases.” Reply Br. 5–7. Examiner has not shown that
these trends would have been obvious to one of skill in the art, or otherwise
expected from the cited prior art. Thus, the record supports Appellant’s
argument the recited molar ratio ranges achieve an unexpected balance
wherein an esterified cellulose ether with a higher Mw is obtained using a
significantly lower amount of catalyst than that taught in the prior art.
For these reasons, and based on the record presently before us, we
agree with Appellant that the recited molar ratio ranges are critical and
probative of non-obviousness. Considering “the entire merits of the matter”
in light of this evidence, we determine that the preponderance of the
evidence does not support the rejection. See In re Hedges, 783 F.2d 1038,
1039 (Fed. Cir. 1986). Accordingly, we reverse.
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CONCLUSION
In summary:
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–6, 9–16 103 Onda, Cade, Odidi 1–6, 9–16

REVERSED