Univation Technologies, LLC

Patent Trials and Appeals Board

Mar 26, 2020

15506559 - (D) (P.T.A.B. Mar. 26, 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.
15/506,559 02/24/2017 Kevin J. Cann 2014U025-US-PCT 9137
76104 7590 03/26/2020
The Dow Chemical Company/Brooks Cameron & Huebsch
1201 MARQUETTE AVENUE SOUTH, SUITE 400
Minneapolis, MN 55403
EXAMINER
NGUYEN, COLETTE B
ART UNIT PAPER NUMBER
1732
NOTIFICATION DATE DELIVERY MODE
03/26/2020 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):
DOW.DOCKETING@BIPL.NET
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte KEVIN J. CANN, MARK G. GOODE,
KEVIN R. GROSS, and JOHN H. MOORHOUSE
Appeal 2019-003439
Application 15/506,559
Technology Center 1700
Before LINDA M. GAUDETTE, GEORGE C. BEST, and
JEFFREY W. ABRAHAM, Administrative Patent Judges.
GAUDETTE, Administrative Patent Judge.
DECISION ON APPEAL1
The Appellant2 appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision finally rejecting claims 1–4 and 6–16 under 35 U.S.C. § 103 as

1 This Decision includes citations to the following documents: Specification
filed February 24, 2017 (“Spec.”); Final Office Action dated May 16, 2018
(“Final”); Appeal Brief filed October 16, 2018 (“Appeal Br.”); Examiner’s
Answer dated January 24, 2019 (“Ans.”); and Reply Brief filed March 25,
2019 (“Reply Br.”).
2 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. The Appellant identifies the real party in interest as Univation
Technologies, LLC. Appeal Br. 3.
Appeal 2019-003439
Application 15/506,559

2
unpatentable over Moorhouse (US 2011/0010938 A1, published Jan. 20,
2011) in view of Palackal (US 2009/0306317 A1, published Dec. 10, 2009).3
We REVERSE.
CLAIMED SUBJECT MATTER
The invention relates to preparing and reducing chromium-based
catalysts used in the polymerization of an olefin into a polyolefin. Spec. ¶ 1.
The Specification discloses that the desired molecular weight and flow index
of a polyolefin, e.g., polyethylene, is dependent on its application. Id. ¶ 2.
According to the Specification, two known chromium-based catalysts for
producing high density polyethylenes include silyl chromate-based catalysts
and chromium oxide-on-silica catalysts. Id. ¶ 4. The inventors are said to
have discovered that adjusting “drying line-out temperature” during
chromium-based catalyst production produces a catalyst that, when used to
produce a polyolefin, can affect its molecular weight. Appeal Br. 6. “[T]he
‘drying line-out temperature’ is the temperature at which a catalyst is dried
after exposure to a solvent.” Id. (citing Spec. ¶¶ 94–98). The drying line-out
temperature affects the catalyst’s flow index response, i.e., the flow index
range of a polymer made by using the catalyst under a given set of
polymerization conditions. Spec. ¶ 11. Polymer flow index is inversely
related to polymer molecular weight. Id. ¶ 33.
Claim 1, the sole independent claim on appeal, is illustrative of the
claimed subject matter:
1. A method of preparing a chromium-based catalyst for the
polymerization of an olefin into a polyolefin, the method
comprising:

3 We have jurisdiction under 35 U.S.C. § 6(b).
Appeal 2019-003439
Application 15/506,559

3
contacting a chromium-based catalyst with a reducing
agent in a solvent to lower an oxidation state of at least some
chromium in the chromium-based catalyst to give a mixture of
a reduced chromium-based catalyst and the solvent, wherein the
chromium-based catalyst comprises a chromium oxide catalyst;
drying the reduced chromium-based catalyst at a drying
line-out temperature; and
adjusting the drying line-out temperature to change the
flow index response of the reduced chromium-based catalyst.
Appeal Br. 14 (Claims Appendix).
OPINION
The Examiner rejected claims 1–4 and 6–16 over Moorhouse and
Palackal. See generally Final 2–5. The Examiner found that Moorhouse
discloses a method of preparing a chromium oxide or silylchromate catalyst
with a reducing agent in an alkane solvent. Id. at 2. The Examiner found that
Moorhouse discloses that reducing agent feed rate and agitation rate effect
the catalyst’s flow index response. Id. at 3; see Moorhouse ¶ 65. Moorhouse
discloses that a polymer’s flow index is “a measure of the ability of [the]
material to flow under pressure and temperature[, and] . . . is an indirect
measure of molecular weight, with high flow index corresponding to low
molecular weight.” Moorhouse ¶ 38. Moorhouse discloses drying the
catalyst slurry at a temperature from 0 to 100 °C to remove the solvent.
Moorhouse ¶ 72. The Examiner found, however, that Moorhouse does not
disclose that “drying line-out temperature . . . effects flow index response
and thus molecular weight of the polymer when the catalyst is used in a
polymerization process, and thus should also be adjusted.” Final 3.
The Examiner found that Palackal discloses a process for preparing a
silylchromate catalyst that includes steps of adding a reducing agent and
Appeal 2019-003439
Application 15/506,559

4
drying. Final 3. The Examiner found that Palackal discloses that the
molecular weight of a polymer produced using the catalyst varies with
drying temperature used during the catalyst’s production. Id. (citing Palackal
Tables 1, 2). The Examiner found that the ordinary artisan at the time of the
invention would have modified Moorhouse’s catalyst preparation method to
also control drying temperature based on Palackal’s disclosure. Id. The
Examiner found that although Palackal’s teaching is limited to silylchromate
catalysts, the ordinary artisan would have expected the same effect on
polymer molecular weight when using a chromium oxide catalyst given
Moorhouse’s disclosure that reducing agent feed rate and agitation rate have
a similar effect on the flow index responses of chromium oxide catalysts and
silylchromate catalysts. Id.
The Appellant argues that the Examiner relied on improper hindsight
reasoning in finding that the ordinary artisan would have understood from
Palackal’s disclosure that drying line-out temperature has an effect on a
catalyst’s flow index response. Appeal Br. 8. The Appellant argues that the
difference between Palackal’s Table 1 and Table 2 examples was not limited
to drying line-out temperature, and directs us to Palackal paragraphs 10–11,
wherein Palakal discloses that a combination of six different factors are
responsible for significantly reduced silylchromate catalyst preparation time.
Appeal Br. 9. The Appellant argues that given the numerous variables, the
ordinary artisan would not have recognized drying line-out temperature as
the result-effective variable that changes a catalyst’s flow index response. Id.
The Appellant also argues that Moorhouse already provides a catalyst
manufacturing method that enables control over, or tailoring of, a catalyst’s
flow index response and, therefore, one of ordinary skill in the art would not
Appeal 2019-003439
Application 15/506,559

5
have had a reason to modify Moorhouse’s catalyst preparation method. See
id. at 10.
The Appellant’s arguments are persuasive of reversible error in the
Examiner’s conclusion of obviousness. As argued by the Appellant, Palackal
fails to disclose two catalyst preparation methods that differ in drying
temperature only. Contrary to the Examiner’s contention that the sole
difference in Palackal’s Examples I and II is drying temperature (Ans. 8),
these two examples also differ in that the catalyst was prepared using
different bis-triphenysilylchromate amounts, resulting in different Al:Cr
ratios (see Reply Br. 4–5). See Palackal Table 1; compare id. ¶ 45, with id.
¶ 46. The Examiner has not identified evidence, or provided explanation, to
support a finding that an ordinary artisan would have attributed the
differences in the molecular weights of polymers produced using the
Example I and Example II catalysts (see Palackal Table 2) to the different
drying temperatures rather than the different bis-triphenysilylchromate
amounts used in preparing the catalysts. As further argued by the Appellant,
Palackal discloses that increases in polymer productivity are due to
decreases in drying time, but does not comment on drying temperature.
Reply Br. 4 (citing Palackal ¶ 53).
We also agree with the Appellant that the Examiner has not explained
sufficiently why the ordinary artisan would have modified Moorhouse’s
method, as Moorhouse already achieves a catalyst having a desired flow
index response. For example, the Examiner has not shown that modifying
Moorhouse’s method to also control drying temperature would have
provided some further improvement to the catalyst or achieved some other
advantage.
Appeal 2019-003439
Application 15/506,559

6
CONCLUSION
The Appellant has identified reversible error in the Examiner’s
conclusion that claims 1–4 and 6–16 are unpatentable over the combination
of Moorhouse and Palackal.
DECISION SUMMARY
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–4, 6–16 103 Moorhouse, Palackal 1–4, 6–16

REVERSED