Jan Van Egmond et al.

Patent Trials and Appeals Board

May 28, 2021

2020001647 (P.T.A.B. May. 28, 2021)

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.
12/941,440 11/08/2010 Jan W. Van Egmond GRACE 3.0-021 9747
122913 7590 05/28/2021
GRACE
Lerner, David, Littenberg, Krumholz & Mentlik, LLP
20 Commerce Drive
Cranford, NJ 07016
EXAMINER
BLACKWELL, GWENDOLYN
ART UNIT PAPER NUMBER
1762
NOTIFICATION DATE DELIVERY MODE
05/28/2021 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):
eOfficeAction@lernerdavid.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
_________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte JAN W. VAN EGMOND
and PING CAI
__________

Appeal 2020-001647
Application 12/941,440
Technology Center 1700
___________

Before ADRIENE LEPIANE HANLON, BRIAN D. RANGE, and
DEBRA L. DENNETT, Administrative Patent Judges.

HANLON, Administrative Patent Judge.

DECISION ON APPEAL

A. STATEMENT OF THE CASE
The Appellant1 filed an appeal under 35 U.S.C. § 134(a) from an Examiner’s
decision finally rejecting claims 1–7, 9, 10, 12–18, and 20–22. We have
jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 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 W.R. GRACE & CO.
CONN. Appeal Brief dated July 15, 2019 (“Appeal Br.”), at 1.
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Independent claim 1, the sole independent claim on appeal, is reproduced
below from the Claims Appendix to the Appeal Brief. The limitations at issue are
italicized.
1. A method for polymerizing propylene, optionally with one or
more additional comonomers, comprising:
a. introducing catalyst into a gas phase reactor, wherein the
catalyst comprises one or more Ziegler-Natta procatalyst
compositions comprising one or more transition metal compounds and
an internal electron donor and wherein the gas phase reactor has a
reactor temperature greater than 70°C;
b. introducing a recycle fluid comprising propylene and
optionally comonomer into the gas phase reactor, said recycle fluid
having a given dew point at the inlet to the gas phase reactor;
c. introducing a mixed external electron donor system to the
reactor, wherein the mixed external electron donor system comprises
at least one selectivity control agent and at least one activity limiting
agent into the gas phase reactor; wherein:
(i) the activity limiting agent is a carboxylic acid
ester, a diether, a poly(alkene glycol), a diol ester, or a
combination thereof; and
(ii) the selectivity control agent is selected from the
group consisting of an alkoxysilane, an amine, an ether, a
carboxylate, a ketone, an amide, a carbamate, a phosphine, a
phosphate, a phosphite, a sulfonate, a sulfone, a sulfoxide, and
combinations thereof;
wherein the method is characterized by having a difference
between the reactor temperature and the dew point temperature of the
recycle fluid of 12° C, or greater.
Appeal Br. 13.
The Examiner maintains the following grounds of rejection on appeal:
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(1) claims 1–7, 9, 10, 12–15, 17, 18, and 20–22 under 35 U.S.C. § 103(a)
as unpatentable over Chen 2752 in view of Turkistani;3 and
(2) claim 16 under 35 U.S.C. § 103(a) as unpatentable over Chen 275 in
view of Turkistani, further in view of Sheard.4
We sustain the obviousness rejections on appeal for substantially the same
reasons provided in the Final Office Action dated September 20, 2018 (“Final
Act.”) and the Examiner’s Answer dated November 1, 2019 (“Ans.”). We add the
following discussion for emphasis.
B. DISCUSSION
Claim 1 is directed to a method for polymerizing propylene. According to
the claimed method, a mixed external electron donor system is introduced into a
gas phase reactor with one or more Ziegler-Natta procatalyst compositions and a
recycle fluid comprising propylene. Appeal Br. 13. The mixed external electron
donor system comprises at least one selectivity control agent and at least one
activity limiting agent. Appeal Br. 13. Claim 1 recites that “the method is
characterized by having a difference between the reactor temperature and the dew
point temperature of the recycle fluid of 12° C, or greater.” Appeal Br. 13; see
also Spec. 2, ll. 5–7 (referring to “the difference between the temperature of the
fluidized bed and the dew point temperature of the recycle gas” as the “‘bed minus
dew temperature’”).
The Examiner finds Chen 275 discloses a method for polymerizing
propylene as recited in claim 1, with the exception of the claimed bed minus dew
temperature. See Final Act. 2–3. The Appellant does not direct us to any error in

2 US 2007/0027275 A1, to Chen et al., published February 1, 2007 (“Chen 275”).
3 US 6,759,489 B1, to Turkistani, issued July 6, 2004 (“Turkistani”).
4 US 2009/0209706 A1, to Sheard et al., published August 20, 2009 (“Sheard”).
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that finding. See Appeal Br. 7. Rather, the Appellant argues that the Examiner
reversibly erred in concluding that the claimed temperature difference would have
been obvious to one of ordinary skill in the art based on the disclosure of
Turkistani. See, e.g., Appeal Br. 8.
Looking more closely at the obviousness rejection of claim 1, the Examiner
finds that the polymerization process disclosed in Chen 275 “includes the use of
condensing mode, wherein gaseous components including low boiling compounds
are injected into the reactor in liquid form for purposes of heat removal.” Final
Act. 3 (citing Chen 275, at ¶ 62).
Turkistani describes a “condensing mode” as follows:
In general, polymerization reactions are exothermic. Therefore,
producing a polymer in a fluidized bed necessitates that the heat
generated by the polymerization reaction be removed in order to keep
the reaction temperature within the bed in a desirable range.
Conventionally, the temperature of the reactor fluidized bed is
controlled to an essentially isothermal level through continuously
removing the heat of polymerization by circulating the gas exiting
from the fluidized bed to a condenser/heat exchanger outside the
reactor and recirculating the cooled gas stream back into the
reactor. . . . [I]t has been recognized that the recycled stream need not
be completely gaseous but can comprise both gas and liquid. In this
process, fluid is formed by cooling the recycle stream below the dew
point temperature,[5] thereby converting a portion of the gas into a
liquid, and the cooled recycle stream is introduced into the fluidized

5 Turkistani discloses,
Conventionally, the dew point or dew point temperature of a
gas is the temperature at which that gas is saturated with respect to a
condensable component. Thus, as a gas is cooled, the dew point
temperature of that gas is that temperature at which liquid condensate
begins to form in the gaseous portion.
Turkistani, col. 17, ll. 17–22.
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bed polymerization reactor. This mode of operation is known in the
art as a “condensing mode” or “condensed mode” process.
Turkistani, col. 1, ll. 14–36 (emphasis added).
The Examiner finds “Chen [275] does not provide further details regarding
the recommended condensing mode operation, such as the dew point of the recycle
fluid.” Final Act. 3. Nonetheless, the Examiner finds that “one of ordinary skill in
the art would be motivated to consult similar olefin polymerization methods
wherein effective parameters for condensing mode operation are described.” Final
Act. 3.
The Examiner finds Turkistani, like Chen 275, discloses a process for
polymerizing propylene. Final Act. 3; Turkistani, col. 6, ll. 62–63 (disclosing that
in one embodiment, “the method is directed to the polymerization of propylene”).
The Examiner further finds that the method disclosed in Turkistani
comprises introducing a recycle fluid comprising propylene into the
gas phase reactor, said recycle fluid having a given dew point at the
inlet to the gas phase reactor, wherein the difference between the
reactor temperature and the dew point temperature of the recycle fluid
is about 15°C or greater, in order to increase the cooling capacity of
the reactor for the benefit of increasing the production rate of the
polymerization reactor.
Final Act. 3 (citations omitted); see also Turkistani, col. 17, ll. 44–53 (disclosing
that the difference between the reactor bed temperature and the recycle stream dew
point temperature may be “greater than or equal to about 5° C,” “greater than or
equal to about 10° C,” and “greater than or equal to about 15° C”).
The Examiner concludes that it would have been obvious to one of ordinary
skill in the art
to introduce a recycle fluid comprising propylene into a fluidized bed
gas phase reactor operating in condensing mode as recommended in
Chen [275], further operating at a difference between the reactor
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temperature and the dew point temperature of the recycle fluid of
about 15°C or greater as recommended in Turkistani, in order to
improve the cooling capacity of the reactor for the expected benefit of
increasing the production rate of the polymerization, because each of
Chen [275] and Turkistani recommend fluidized bed polymerization
of propylene using condensing mode, and Turkistani provides further
recommendations for selecting effective process parameters for the
condensing mode system.
Final Act. 3–4.
The Appellant argues that the Examiner’s reliance on Turkistani in the
obviousness rejections on appeal was erroneous. See, e.g., Appeal Br. 12. More
specifically, the Appellant argues that one of ordinary skill in the art would have
considered Chen 067,6 not Turkistani, the most relevant reference for determining
the “bed minus dew temperature” in Chen 275’s process because, in contrast to
Turkistani, Chen 067 uses catalyst systems of the type disclosed in Chen 275 and
recited in the claims on appeal. Appeal Br. 7. That being said, the Appellant
argues that Chen 067 would not have led one of ordinary skill in the art to the
claimed invention because Chen 067 “discloses a bed minus dew temperature
difference of 1–10°C or less,” which falls outside the claimed range of 12°C or
greater. Appeal Br. 7–8.
There is no dispute on this record that Turkistani’s polymerization process
uses Ziegler-Natta catalysts. See Turkistani, col. 7, ll. 4–5, 21–22 (disclosing that
“[t]he catalyst or catalysts used in the method of the invention are conventional”
and “[i]n particular, the conventional catalyst can be of the Ziegler-Natta type”);
Final Act. 4 (finding that Turkistani uses a Ziegler catalyst). Nonetheless, the
Appellant argues that Turkistani “does not disclose or require use of internal or

6 US 2011/0152067 A1, to Chen et al., published June 23, 2011 (“Chen 067”).
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external electron donors [as recited in claim 1 on appeal] in connection with its
generic reference to Ziegler-Natta catalysts.” Appeal Br. 10.
The Appellant contends that internal and external electron donor
components are “generally, if not universally, used in processes for polymerization
of propylene.” Appeal Br. 10. However, the Appellant argues that Turkistani only
exemplifies the polymerization and copolymerization of ethylene and Ziegler-
Natta catalyst systems intended for ethylene polymerization do not employ those
donors. Appeal Br. 10–11.
The Appellant’s argument is not persuasive of reversible error. It is of no
moment in the obviousness rejection on appeal that the examples in Turkistani are
not directed to a process for polymerizing propylene. See In re Lamberti, 545 F.2d
747, 750 (CCPA 1976) (“all disclosures of the prior art, including unpreferred
embodiments, must be considered”). Turkistani expressly discloses that in one
embodiment of the invention, “the method is directed to the polymerization of
propylene.” Turkistani, col. 6, ll. 62–63. Thus, based on the Appellant’s
contention above, it appears that one of ordinary skill in the art would have
understood that internal and external electron donor components are used in
Turkistani’s process for polymerizing propylene. See Appeal Br. 10 (contending
that internal and external electron donor components are “generally, if not
universally, used in processes for polymerization of propylene”).
Nonetheless, the Appellant does not direct us to any evidence establishing
that the absence of internal and/or external electron donors in Turkistani’s process
would have led one of ordinary skill in the art away from using Turkistani’s bed
minus dew temperatures in Chen 275’s process. The mere fact that differences
may exist between Chen 275’s and Turkistani’s catalyst systems does not suffice.
See Ans. 8 (explaining that the Appellant’s assertion that “certain mixed electron
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donors [have] some bearing on selection of bed minus dew point temperature finds
no support in the record, and the particulars of electron donors do[] not appear to
have any relevance for selection of parameters for obtaining effective cooling by
use of a condensing recycle system.”).7
In sum, a preponderance of the evidence of record establishes that one of
ordinary skill in the art would have had a reasonable expectation of successfully
polymerizing propylene according to Chen 275’s process wherein the bed minus
dew temperature is 10°C as disclosed in Chen 067, or is greater than 12°C as
taught by Turkistani.8
The obviousness rejections of the claims on appeal are sustained.9
C. CONCLUSION
The Examiner’s decision is affirmed.

7 In the Reply Brief, the Appellant argues that Chen 067 discloses that “the use of
specific external donors can limit the temperature rise in the reactor so as to
prevent a ‘runaway’ temperature increase and its debilitating effects.” Reply Brief
dated December 24, 2019, at 7. The Appellant does not provide a citation to Chen
067 supporting the Appellant’s argument. Moreover, the Appellant does not
explain, in any detail, why this purported disclosure in Chen 067 would have led
one of ordinary skill in the art away from a bed minus dew temperature within the
ranges disclosed in Turkistani.
8 The Appellant contends that the claimed method can be carried out without
fouling or static problems. Appeal Br. 3. Notably, Chen 275 discloses that the use
of a selectivity control agent (SCA) and an activity limiting agent (ALA), as
recited in Appellant’s claim 1, reduces softening or melting of polymer particles
that leads to agglomerate formation and sheeting or fouling of the reactor. Chen
275, at ¶ 92.
9 The Appellant does not present arguments in support of the separate patentability
of any of the dependent claims on appeal.
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In summary:

Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–7, 9, 10,
12–15, 17,
18, 20–22
103(a) Chen 275,
Turkistani
1–7, 9, 10,
12–15, 17,
18, 20–22

16 103(a) Chen 275,
Turkistani, Sheard
16
Overall
Outcome
1–7, 9, 10,
12–18, 20–22

No time period for taking any subsequent action in connection with this
appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED