Ex Parte Razavi

Board of Patent Appeals and Interferences

Jan 29, 2009

10562718 (B.P.A.I. Jan. 29, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte ABBAS RAZAVI
____________

Appeal 2008-3875
Application 10/562,718
Technology Center 1700
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Decided: January 29, 2009
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Before EDWARD C. KIMLIN, TERRY J. OWENS, and
JEFFREY T. SMITH, Administrative Patent Judges.

SMITH, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on an appeal under 35 U.S.C. § 134 from the
Primary Examiner’s rejection of claims 12-25. We have jurisdiction
pursuant to 35 U.S.C. § 6. 1

1 In rendering this decision we have considered the Appellant’s arguments
presented in the Appeal Brief dated July 03, 2007.

Appeal 2008-3875
Application 10/562,718

Appellant’s invention is directed to a process for the preparation of an
isotactic/syndiotactic polypropylene blend comprising: (a) providing a
catalyst system comprising an isospecific metallocene catalyst component
and a syndio specific metallocene catalyst component effective for the
polymerization of propylene; and (b) contacting said catalyst system with
propylene under polymerization conditions to produce a blend of an isotactic
polypropylene component A that is crystalline and a syndiotactic
polypropylene component B that is less crystalline than said isotactic
polypropylene component A. Claim 25 is representative of the invention
and is reproduced below:
25. A process for the preparation of an isotactic/syndiotactic
polypropylene blend comprising:

providing a catalyst system comprising:

an isospecific metallocene catalyst component
represented by the formula

R"(CpR1R2R3)(Cp'RYn)MQ2,

wherein Cp is a substituted cyclopentadienyl ring, Cp' is a substituted
or unsubstituted fluorenyl ring, R" is a structural bridge imparting
stereorigidity to isospecific metallocene catalyst component, R1 is a
substituent on the cyclopentadienyl ring which is distal to the bridge,
which distal substituent comprises a bulky group of the formula ZR*3
in which Z is an atom from group 14 of the Periodic Table and each
R* is the same or different and is chosen from a hydrogen or a
hydrocarbyl group having from 1-20 carbon atoms, R2 is a substituent
on the cyclopentadienyl ring which is proximal to the bridge and
positioned non-vicinal to the distal substituent and is H or a group of
the formula YR#3 in which Y is an atom from group IVA, and each
R# is the same or different and is chosen from a hydrogen or a
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Appeal 2008-3875
Application 10/562,718

hydrocarbyl group having from 1-7 carbon atoms, R3 is a further
substituent on the cyclopentadienyl ring and may be the same or
different from R2 and is H or a group of the formula YR#3 in which Y
is an atom from group 14, and each R# is the same or different and is
chosen from a hydrogen or a hydrocarbyl group having from 1-7
carbon atoms, each R'n is the same or different and is a hydrocarbyl
group having from 1-20 carbon atoms, and n is an integer of from 0-8;
M is a metal atom from group 4 of the Periodic Table or is vanadium;
and each Q is a hydrocarbon having from 1-20 carbon atoms or is a
halogen; and

a syndiospecific metallocene catalyst component
represented by the formula:

R"(CpRx)(Cp'R'y)MQ2

wherein Cp is a substituted or unsubstituted cyclopentadienyl ring,
Cp' is a substituted or unsubstituted fluorenyl ring, R" is a structural
bridge imparting stereorigidity to the syndiospecific metallocene
catalyst component, each R is the same or different and is a
hydrocarbyl group having from 1-20 carbon atoms, each R' is the
same or different and is a hydrocarbyl group having from 1-20 carbon
atoms, and x and y are independently an integer of from 0-4 and 0-8
respectively; M is a metal atom from group 4 or is vanadium; and
each Q is a hydrocarbon having from 1-20 carbon atoms or is a
halogen; and wherein the substituents are selected in order to impart
bilateral symmetry to the catalyst component; and

contacting said catalyst system with propylene under
polymerization conditions to produce a blend of an isotactic
polypropylene component A that is crystalline and a syndiotactic
polypropylene component B that is less crystalline than said isotactic
polypropylene component A, said blend being characterized by a
molecular weight distribution that has a single composite peak and a
polydispersity of 4 or less.

3

Appeal 2008-3875
Application 10/562,718

Claims 12-17 and 22-25 stand rejected under 35 U.S.C. § 103(a) over
Shamsoum, U.S. Pat. No. 6,13,683, issued on November 7, 2000, in view of
Kawai, European Patent No. 1,138,687, published October 4, 2001; Claims
18-21 stand rejected under 35 U.S.C. § 103(a) over Shamsoum in view of
Kawai, and Demain, PCT International Patent No WO 00/60148 2 published
October 12, 2000.

ISSUES ON APPEAL
Appellant contends, regarding the syndiospecific metallocene
component, that Shamshoum does not teach a syndiospecific metallocene
component including a Cp ring and a fluorenyl ring, as recited in pending
claim 25. Relying on In re Baird, 16 F.3d 380, 382 (Fed. Cir. 1992),
Appellant contends that “there must be a suggestion in the reference to select
the particular combination of variables in the formula”.3 (App. Br. 4).
Regarding the isospecific metallocene component, Appellant contends that
the prior art would not have led the skilled person to replace the indenyl
ligands of Shamshoum with the ligands taught by Kawai because such a
replacement would render the catalyst of Shamshoum inoperable for the

2 The Examiner cited the U.S. Patent No. 6,646,051, issued on November
11, 2003 as an English language equivalent for the WO 00/60148 reference.
(Ans. 4).
3 Appellant has grouped their arguments for claims 12-17 and 19-25
together. While Appellant addresses separately rejected claims 18-21,
Appellant relies on the reasons presented in rebuttal to the Examiner’s
rejection of claim 25. (App. Br. 6). Consequently, the appealed claims
stand or fall with claim 25. Our analysis will be limited thereto.

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Appeal 2008-3875
Application 10/562,718

intended purpose, specifically, the preparation of bimetallic catalyst systems
including indenyl bridged metallocenes to produce bimodal molecular
weight distribution compositions.. (App. Br. 5).
The issue presented is: did Appellant identify reversible error in the
Examiner’s rejection of claim 25 under § 103? We answer this question in
the negative. The issue turns on whether it would have been obvious to a
person of ordinary skill in the art to utilize a catalyst system comprising a
syndiospecific metallocene component including a Cp ring and a fluorenyl
ring and an isospecific metallocene component containing a bridged
cyclopentadienyl and fluorenyl ligand to prepare an isotactic/syndiotactic
polypropylene blend.

OPINION
We have thoroughly reviewed each of Appellant’s arguments for
patentability. However, we are in complete agreement with the Examiner
that the claimed subject matter is not patentable within the meaning of § 103
in view of the applied prior art. Accordingly, we will sustain the Examiner’s
rejection.
The Examiner found that Shamshoum teaches a process for the
preparation of isotactic and syndiotactic polypropylene blend by
polymerization of propylene in the presence of a catalyst composition
prepared by supporting an isotactic metallocene catalyst and a syndiotactic
metallocene catalyst. (Ans. 3; Shamshoum, col. 1, ll. 22-29, col. 2, ll. 2).
The Examiner found that Ewen, a reference incorporated by reference in
Shamshoum, describes a metallocene catalyst comprising syndiotactic
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Appeal 2008-3875
Application 10/562,718

metallocene components including isopropyl(fluorenyl)(cyclopentadienyl)
hafnium dichloride and isopropyl(fluorenyl)(cyclopentadienyl) zirconium
dichloride (Shamshoum, col. 5, ll. 64-67; Ewen, col. 9, Ex. 1 and col. 11, Ex.
3). The Examiner further noted that Shamshoum does not expressly teach
the isotactic metallocene component to be a metallocene containing a
bridged cyclopentadienyl and fluorenyl ligand. However, the Examiner
found that Kawai describes that it was known to use a metallocene
containing a bridged cyclopentadienyl and fluorenyl ligand to prepare
isotactic propylene polymers. (Ans. 4; Kawai, Abstract, paragraphs [0107]-
[0134], and Examples 47-126). The Examiner concluded that a person of
ordinary skill in the art would have found it obvious to prepared
Shamshoum’s isotactic and syndiotactic polypropylene blend utilizing a
metallocene catalysts including isopropyl(fluorenyl)(cyclopentadienyl)
hafnium dichloride and isopropyl(fluorenyl)(cyclopentadienyl) zirconium
dichloride, each complex respectively containing a cyclopentadienyl ring
and a fluorenyl ring.
“Section 103 forbids issuance of a patent when ‘the differences
between the subject matter sought to be patented and the prior art are such
that the subject matter as a whole would have been obvious at the time the
invention was made to a person having ordinary skill in the art to which said
subject matter pertains.’” KSR Int'l Co. v. Teleflex Inc., 127 S. Ct. 1727,
1734 (2007) (citing 35 U.S.C. § 103 (a)). The legal question of obviousness
is resolved on the basis of underlying factual determinations including (1)
the scope and content of the prior art, (2) any differences between the
claimed subject matter and the prior art, (3) the level of skill in the art, and
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Appeal 2008-3875
Application 10/562,718

(4) secondary considerations, if any. Graham v. John Deere Co., 383 U.S.
1, 17-18 (1966). See also KSR, 127 S. Ct. at 1734.
As shown by the findings above, a person of ordinary skill in the art
would have recognized that it was known to form and utilize a metallocene
catalyst which has two different sites, syndiospecific and isospecific, on the
same support. (See Shamshoum). Regarding the syndiospecific metallocene
catalyst component, the Examiner cited prior art that establishes that the
formation of a syndiospecific metallocene component including a Cp ring
and a fluorenyl ring was known to persons of ordinary skill in the art.
Likewise, regarding isospecific metallocene catalyst component the
Examiner cited prior art that establishes that the formation of an isospecific
metallocene component including a Cp ring and a fluorenyl ring was known
to persons of ordinary skill in the art. Thus, the Examiner properly
concluded that a person of ordinary skill in the art would have reasonably
expected that the known syndiospecific metallocene component and
isospecific metallocene component would have been suitable for the
formation of a metallocene catalyst comprising a syndiospecific metallocene
component and isospecific metallocene component on the same support
suitable for preparation of polypropylene blends. The Examiner also
properly concluded that a person of ordinary skill in the art would have
found it obvious to prepare an isotactic and syndiotactic polypropylene
blend utilizing a metallocene catalysts including
isopropyl(fluorenyl)(cyclopentadienyl) hafnium dichloride and
isopropyl(fluorenyl)(cyclopentadienyl) zirconium dichloride, each complex
respectively containing a cyclopentadienyl ring and a fluorenyl ring.
7

Appeal 2008-3875
Application 10/562,718

The prior art relied upon by the Examiner establishes that a person of
ordinary skill in the art would have recognized that a metallocene containing
a bridged cyclopentadienyl and fluorenyl ligand may be used to prepare
polypropylene comprising syndiotactic propylene polymers and isotactic
propylene polymers.
Appellant’s arguments regarding the syndiospecific metallocene
component and the isospecific metallocene component are not persuasive for
the reasons set forth above. “[W]hen a patent claims a structure already
known in the prior art that is altered by mere substitution of one element for
another known in the field, the combination must do more than yield a
predictable result.” KSR, 127 S. Ct. at 1740. Appellant has not directed us
to evidence that establishes the presently claimed invention achieves more
than predictable results.
Appellant’s arguments (Br. 4) regarding Shamshoum’s failure to have
the claimed polypropylene blend with a molecular weight distribution that
has a single composite peak are not persuasive for the reasons stated in the
Answer page 7. A person of ordinary skill in the art would have recognized
the conditions necessary to produce a unimodal polypropylene blend from
the teachings of the cited prior art. Appellant has failed to refute the
Examiner’s position in responsive briefing.
For the foregoing reasons and those stated in the Answer, we affirm
the rejections presented in this appeal.
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Appeal 2008-3875
Application 10/562,718

ORDER
The rejections of claims 12-17 and 22-25 under 35 U.S.C. § 103(a) over
Shamshoum and Kawai; and claims 18-21 under 35 U.S.C. § 103(a) over
Shamshoum, Kawai, and Demain are affirmed.
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

PL Initial:
sld

FINA TECHNOLOGY INC
P.O. BOX 674412
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