Ex Parte Conner et al

Board of Patent Appeals and Interferences

Apr 25, 2008

10753635 (B.P.A.I. Apr. 25, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte MARK DAVID CONNER,
JOHN J. KOCH, and
RICHARD JOSEPH GODDARD
____________

Appeal 2008-0328
Application 10/753,635
Technology Center 1700
____________

Decided: April 25, 2008
____________

Before BRADLEY R. GARRIS, CATHERINE Q. TIMM, and
LINDA M. GAUDETTE, Administrative Patent Judges.

TIMM, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
decision rejecting claims 1-17. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

Appeal 2008-0328
Application 10/753,635

I. BACKGROUND
The invention relates to a prepolymer composition of at least 70% by
weight of a 2:1 adduct of isophorone diisocyanate (IPDI) and polypropylene
glycol (PPG). The IPDI and PPG reaction is typically achieved using a large
stoichiometric excess of IPDI. The invention uses distillation to reduce the
residual IPDI to less than 1% by weight. Claims 1, 8, 12 and 14 are
illustrative of the subject matter on appeal:
1. A prepolymer composition comprising at least 70 wt.%
of a 2:1 adduct of isophorone diisocyanate (IPDI) and polypropylene
glycol (PPG), and comprising less than 1 wt.% residual IPDI, wherein
all weight percentages are based on a weight of the prepolymer
composition.

8. A process for preparing the prepolymer composition of
claim 1, said process comprising reacting IPDI with PPG at an
NCO:OH ratio greater than 2:1 to provide a product mixture
comprising the 2:1 adduct, and distilling residual IPDI from the
product mixture to provide the prepolymer composition.

12. The process of claim 8, wherein the PPG has a molecular
weight greater than 1500 and the process is conducted with a catalyst.

14. The process of claim 8, wherein the residual IPDI is
distilled at a temperature greater than 100ºC, and the process is
conducted with a catalyst.

The Examiner relies on the following prior art references to show
unpatentability:
Quay et al. (“Quay”) US 5,115,071 May 19, 1992
Thompson et al. (“Thompson”) US 5,449,704 Sep. 12, 1995
Rosenberg et al. (“Rosenberg II”) US 5,703,193 Dec. 30, 1997
Peter US 6,174,984 B1 Jan. 16, 2001
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Rosenberg et al. (“Rosenberg I”) US 2003/0065124 A1 Apr. 3, 2003
Hofacker et al. (“Hofacker”) US 2003/0120019 A1 Jun. 26, 2003
Zhu et al. (“Zhu”) US 2005/0027090 A1 Feb. 3, 2005

Claims 1-17 are rejected under 35 U.S.C. § 103(a) as obvious over
Hofacker or Thompson, each in view of Zhu, Rosenberg I, Peter, Rosenberg
II or Quay.1
Appellants have chosen to argue separately the following groups of
claims: claims 1-7, claims 8-11, 13 and 15-17, claim 12 and claim 14.
(App. Br. 5-8). In assessing the merits of the 35 U.S.C. § 103(a) rejection,
we focus on representative claims 1, 8, 12 and 14.
II. DISCUSSION
Appellants argue patentability based on the Declaration of Mark D.
Connor, one of the inventors of the present application, and the teachings of
R. Lomolder et al., Selectivity of Isophorone Diisocyanate in the Urethane
Reaction Influence of Temperature, Catalysis and Reaction Partners, 69,
No. 86, J. Coatings Tech. 51 (May 1997) (“Lomolder”). (App. Br. 5-6). In
particular, Appellants argue that the teachings of Lomolder evince that one
of ordinary skill in the art, at the time of the invention, would have been
discouraged from employing a distillation process to remove residual IPDI
from a 2:1 adduct of IPDI-PPG. (App. Br. 5-7). Appellants argue that one
of ordinary skill in the art would have expected thermal instability and
degradation of the prepolymer product, which was known to occur at high
temperatures, particularly greater than 80-100ºC. (App. Br. 5-7).

1 The Examiner withdrew the rejection of claims 1-17 under 35 U.S.C. §
112, first paragraph. (Ans. 2).
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With respect to claim 12, Appellants also add that “[one] of ordinary
skill in the art would have expected further destabilization to result from the
combination of distillation and catalysis.” (App. Br. 7).
The Examiner relies on the teachings of Zhu, Rosenberg I, Peter,
Rosenberg II and Quay (i.e., the “secondary references”) as evidence that
distilling off residual IPDI would have been within the general knowledge of
one of ordinary skill in the art at the time of the invention. (Ans. 5-6). In
particular, the Examiner relies on the teachings of Zhu, Rosenberg I, and
Peter, which teach “how to use IPDI and how to prevent the very thermal
decomposition that appellants are concerned with.” (Ans. 6)
The issue on appeal arising from the contentions of Appellants and the
Examiner is: Would it have been within the capability of one of ordinary
skill in the art to distill a 2:1 adduct IPDI-PPG prepolymer to remove
residual IPDI or, based on the teachings of Lomolder, does the conventional
wisdom in the art teach away from distilling a 2:1 adduct of IPDI-PPG
prepolymer to remove residual IPDI? We answer that it would have been
within the capability of one of ordinary skill in the art to distill a 2:1 adduct
IPDI-PPG prepolymer to remove residual IPDI.
We set forth the following Findings of Facts (FF):
1. Lomolder teaches the formation of an IPDI-PPG prepolymer in
a stoichiometric ratio of NCO:OH of 2:1. (Lomolder 56, col. 2, ¶ 2).
Lomolder teaches that “[t]he somewhat surprising low viscosity of the PPG-
based system produced at 80ºC with no catalyst (15 Pa-s) could be traced
back to the thermal degradation of the comparably weak backbone polyol.”
(Lomolder 56, col. 2, ¶ 3). Lomolder also observed a “significant viscosity
increase” for products catalyzed at 100ºC compared to products catalyzed at
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60ºC and surmises that the viscosity increase “could be attributable to the
formulation of allophonates,” a degradation product of the IPDI/PPG
prepolymers. (Lomolder, 56, col. 2, ¶ 3).
2. Hofacker teaches the formation of prepolymers from
polypropylene oxide glycol (PPG) and an IPDI having less than a 2%
residual IPDI concentration due to the use of polypropylene oxide glycol
prepared with a DMC catalyst so as to exhibit a greater OH- functionality.
(Hofacker, abstract, ¶¶ [0006], [0007] and [0019]). Hofacker further teaches
that alternatively “a subsequent, technically elaborate distillation step (thin
film distillation process) [would be necessary] in order to separate
monomeric constituents, for example IPDI.” (Hofacker, ¶ [0004]).
3. Thompson teaches the formation of prepolymers from
polyoxypropylene glycol (PPG) and a stoichiometric excess of IPDI with
zero residual IPDI. (Thompson, col. 3, ll. 1-38, col. 8, ll. 53-68). Although
the exact mechanism for obtaining zero residual IPDI is not identified in
Thompson, Thompson discloses a subsequent reaction with 2-hydroxyethyl
methacrylate in the presence of hydroquinone. (Thompson, col. 8, ll. 53-68).
4. Zhu teaches prepolymers formed from diisocyanate monomers
(such as IPDI) and polyols (such as PPG) where the “removal of unreacted
diisocyanate monomer can be readily achieved, e.g., by distillation.” (Zhu,
¶¶ [0029], [0030], [0035], and [0041]). The distillation should occur “at a
pressure from about 0.001 to about 10 Torr and at a temperature ranging
from about 80º C. to about 200º C.” (Zhu, ¶ [0042]). Zhu also addresses
“[t]he importance of minimizing high temperature degradation of
polyurethane prepolymers” by referring to additional art recommending
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“distillation be conducted under vacuum with an evaporative temperature
preferably under 175ºC.” (Zhu, ¶ [0042]).
5. Rosenberg I teaches distilling residual amounts of either
aliphatic diisocyanates, such as IPDI, or aromatic diisocyanates from
polyurethane prepolymer products. (Rosenberg I, ¶¶ [0013], [0020] and
[0057]). Rosenberg I teaches “the use of a solvent makes possible the use
of lower evaporator temperatures, thereby avoiding thermal decomposition
of the prepolymer.” (Rosenberg I, ¶ [0065]).
6. Peter teaches distilling to remove unreacted isocyanate from a
prepolymer product as conventional. (Peter, col. 1, ll. 45-51, col. 1, l. 65-
col. 2, l. 5, col. 5, l. 41- col. 6, l. 3). Peter states that ‘[t]he actual
temperature and pressure conditions of the distillation should be such that
the vaporization point of the diisocyanate monomer is exceeded without
decomposing the polyurethane prepolymer. The actual temperature and
pressure can vary, therefore, and are dependent upon the diisocyanate
monomer being removed.” (Peter, col. 6, ll. 4-9).
7. Rosenberg II teaches distilling to remove residual diisocyanate
monomer in the presence of two solvents, one with a higher boiling point
than the diisocyanate monomer and one with a lower boiling point than the
diisocyanate monomer, and at a temperature which is below the
decomposition temperature of the polyurethane monomer. (Rosenberg II,
abstract). In particular, Rosenberg II teaches that “[i]t is known that in the
distillation of diisocyanate monomers from polyurethane prepolymers, high
temperatures must be avoided to prevent decomposition reactions in the
prepolymer.” (Rosenberg II, col. 1, ll. 52-55).
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8. Quay teaches that “unreacted isocyanate monomer is removed
from the prepolymer by distillation or other treatment to a concentration of
less than 1%.” (Quay, col. 3, ll. 54-57). Quay cautions that “[c]are should
be exercised during removal of the excess polyisocyanate so that
allophanates, oligomers and other byproducts are not formed.” (Quay, col.
4, ll. 40-43).
9. While not necessarily utilizing IPDI in the examples provided
therein, each of the secondary references discloses the use of IPDI as a
suitable diisocyanate for a 2:1 (or ABA) adduct polyurethane prepolymer.
(Zhu, ¶¶ [0030] and [0037]-[0039]; Rosenberg I, ¶¶ [0057] and [0060]-
[0061]; Peter, col. 3, ll. 58-61 and col. 8, ll. 1-27; Rosenberg II, col. 3, ll.
15-17 and col. 7, ll. 20-50; Quay, col. 4, ll. 13-18 and col. 4, ll. 31-36).
10. While not necessarily utilizing PPG in the examples provided
therein, each of the secondary references teaches that polypropylene glycol
polyols (i.e., PPG) are suitable polyols for a 2:1 (or ABA) adduct
polyurethane prepolymer. (Zhu, ¶ [0035] and [0037]-[0039], Rosenberg I,
¶¶ [0031] and [0060]-[0061]; Peter, col. 5, ll. 12-18 and col. 8, ll. 1-27;
Rosenberg II, col. 5, ll. 10-14 and col. 7, ll. 20-50; Quay, col. 3, l. 59-col. 4,
l. 2 and col. 4, ll. 31-36).
11. Each of the secondary references includes examples directed
towards distilling aromatic diisocyanates, such as diphenylmethane
diisocyanate (MDI), toluene diisocyanate (TDI), or para-phenylene
diisocyanate (PPDI), but does not include examples directed towards
distilling IPDI. (Zhu, ¶ [0059]; Rosenberg I, ¶ [0051] and [0095]; Peter, col.
8, ll. 65-67; Rosenberg II, col. 6, ll. 54-67; Quay, col. 4, ll. 13-20 and col. 6,
ll. 11-30).
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12. However, Rosenberg I teaches that aromatic diisocyanates are
more difficult to distill than aliphatic diisocyanates because aliphatic
diisocyanates have “lower boiling points and much greater heat stability”
than aromatic diisocyanates. (Rosenberg I, ¶ [0013]).
“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). The 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 (4) where in evidence, so-called
secondary considerations. Graham v. John Deere Co., 383 U.S. 1, 17-18,
(1966). See also KSR, 127 S. Ct. at 1734 (“While the sequence of these
questions might be reordered in any particular case, the [Graham] factors
continue to define the inquiry that controls.”).
Applying the preceding legal principles to the Factual Findings in the
record of this appeal, we determine that the Examiner has established a
prima facie case of obviousness.
First, regarding claim 1, Appellants contend that Lomolder teaches
away or discourages one of ordinary skill in the art from distilling to remove
residual IPDI from a 2:1 adduct IPDI-PPG prepolymer product. (App. Br. 5-
7). However, claim 1 broadly recites a prepolymer product “comprising less
than 1 wt.% residual IPDI.” We decline to read into claim 1 a limitation that
the residual IPDI concentration must be achieved by any particular method
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and particularly that it must be achieved by distillation. Thompson does not
teach distilling yet teaches an IPDI-PPG prepolymer product comprising less
than 1 wt. % residual IPDI. (FF 3). Meanwhile, Hofacker teaches that
distilling was conventional but is directed to an alternative method for
providing an IPDI-PPG prepolymer product with less than 2% residual IPDI.
(FF 2). Since Appellants provide no alternative arguments directed to claim
1, we sustain the Examiner’s rejection of claim 1.
Turning to claim 8, we find Appellants’ reliance on Lomolder as the
only source of evidence of what was conventional knowledge to one of
ordinary skill in the art at the time of the invention to be unpersuasive.
While Lomolder does teach that an IPDI-PPG prepolymer product may
degrade at high temperatures, we agree with the Examiner that the teachings
of Lomolder are limited and are not sufficient evidence to show that
distilling residual IPDI from an IPDI-PPG prepolymer product would not be
successful. (FF 1).
Further, Appellants have not adequately addressed the fact that the
secondary references cited by the Examiner contradict Lomolder as to what
was conventional knowledge to one of ordinary skill in the art at the time of
the invention regarding distilling. Hofacker and the secondary references,
despite cautioning that degradation of prepolymer product may occur at high
temperatures, teach that distilling to remove residual diisocyanate from a
polyurethane prepolymer product would have been well known to one of
ordinary skill in the art. (FF 2 and 4-8).
Appellants’ emphasis on Lomolder as being directed to a 2:1 adduct
of IPDI-PPG prepolymer while the secondary references are not directed to a
2:1 adduct of IPDI-PPG prepolymer is also not persuasive. Each of the
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secondary references teaches reacting IPDI among many alternative
diisocyanates and includes PPG among many alternative polyols used to
form a 2:1 diisocyanate:polyol adduct polyurethane prepolymer product.
(FF 9 and 10). Also, the secondary references teach distilling to remove
residual diisocyanate, e.g., IPDI. (FF 4-8). Since the problem of thermal
instability discussed by Lomolder is acknowledged in each of the secondary
references (FF 4-8), one of ordinary skill in the art having the teachings of
the secondary references would have reasonably expected that an IPDI-PPG
prepolymer product could be successfully distilled to remove residual IPDI.
See Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348, 1364 (Fed. Cir. 2007) (“the
expectation of success need only be reasonable, not absolute”).
Further, even though the secondary references exemplify the use of
aromatic diisocyanates rather than IPDI (FF 11), Rosenberg I teaches that
distilling an aromatic diisocyanate is more difficult than that of IPDI. (FF
12). Therefore, one of ordinary skill in the art would have known that
distilling IPDI would have been likely to be even more successful than that
of the aromatic diisocyanates exemplified in the secondary references.
Thus, we sustain the Examiner’s determination of obviousness of
claim 8.
Regarding claims 12 and 14, Appellants extend the arguments
regarding the obviousness of distilling a 2:1 adduct of an IPDI-PPG
prepolymer to remove residual IPDI discussed above with respect to claim 8
to argue that it would not have been obvious to distill the prepolymer (a) in
combination with reacting the product with a catalyst, as in claim 12, or (b)
at a temperature of 80-100ºC, as in claim 14. (App. Br. 7-8). As discussed
above, we have found Appellants’ arguments regarding the non-obviousness
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of distilling a 2:1 adduct of an IPDI-PPG prepolymer to remove residual
IPDI unpersuasive. Since Appellants have provided no further arguments
regarding claims 12 and 14, we sustain the Examiner’s rejection of claims 12
and 14.
III. CONCLUSION
The totality of the evidence weighs in favor of a conclusion of
obviousness. The Appellants have not demonstrated that the Examiner
reversibly erred in finding claim 1-17 obvious. Accordingly, we sustain the
Examiner's rejections under 35 U.S.C. § 103(a).
IV. DECISION
The decision of the Examiner is affirmed.
V. TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal maybe extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

tf/ls

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PATENT DEPARTMENT
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