Ex Parte Klotzer et al

Patent Trial and Appeal Board

Mar 18, 2013

12065680 (P.T.A.B. Mar. 18, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte MATTHIAS KLOTZER, ECKHARD STROEFER,
VOLKER KRASE, ANDREAS SCHMIDT, and PETER SCHERBEL
__________

Appeal 2011-007504
Application 12/065,680
Technology Center 1600
__________

Before DEMETRA J. MILLS, JEFFREY N. FREDMAN, and
JOHN G. NEW, Administrative Patent Judges.

MILLS, Administrative Patent Judge.

DECISION ON APPEAL

This is an appeal under 35 U.S.C. § 134. The Examiner has rejected
the claims for obviousness. We have jurisdiction under 35 U.S.C. § 6(b).
Appeal 2011-007504
Application 12/065,680

2
STATEMENT OF CASE
Appellants‟ claims are reproduced below:
Claim 1. A process comprising preparing isocyanates by reacting at
least one amine with urea and at least one alcohol to the corresponding
urethane in at least one mixing means with at least one attached residence-
time reactor and subsequently cleaving the resultant urethane into the
corresponding isocyanates, wherein conversion, based on amino groups in
the amine employed to urethane groups, is not more than 10% in said mixing
means.

Claim. The process according to claim 1, wherein said mixing means
is selected from the group consisting of mixing circuit, mixing pump, jet
mixing means, coaxial mixing nozzles, Y -mixer, T -mixer, and vortex
impinging-jet mixing configuration.

Claim 3. The process according to Claim 1, wherein the mixing time
in the mixing means is from 0.0001 to 2 s.

Claim 4. The process according to Claim 1, wherein alcohol and
amine are introduced into the mixing means at a speed between 10 and 100
m/s.

Claim 5. The process according to Claim 1, wherein the residence-
time reactor is a tube reactor.

Claim 6. The process according to Claim 5, wherein the tube reactor
has a Bodenstein number of more than 5.

Claim 7. The process according to Claim 1, wherein the amine is a
diamine.

Claim 8. The process according to Claim 1, wherein the amine is
selected from the group consisting of butane-l ,4-diamine, 2-ethylbutane-1,4-
diamine, octane-l ,8-diamine, decane-l, 10-diamine, dodecane-l, 12-diamine,
cyclohexane-l ,4-diamine, 2-methyl-, and 4- methyl-cyclohexane-l,3-
diamine, 1,3- and 1,4-diaminomethylcyclohexane, 2-methylpentane- 1,5-
diamine, 2,2,4- and 2,4,4-trimethylhexane-l ,6-diamine, hexane-l ,6-diamine,
and 3-aminomethyl-3,5,5-trimethylcyclohexylamine.
Appeal 2011-007504
Application 12/065,680

3
Claim 9. The process according to Claim 1, wherein the alcohol is
selected from the group consisting of methanol, ethanol, n-propanol, n-
butanol, isobutanol, n-pentanol, isopentanol, n-hexanol, isohexanols,
cyclohexanol, 2-ethylhexanol, decanol, and mixtures of said alcohols.

Claim 10. A method for reacting at least one amine with urea and at
least one alcohol to form the corresponding urethane characterized by the
use of a mixing means selected from the group consisting of a mixing
circuit, mixing pump, jet mixing means, coaxial mixing nozzles, Y -mixer, T
-mixer and vortex impinging-jet mixing configuration.

Claim 11. The process according to claim 1, wherein the mixing time
in the mixing means is from 0.0005 to 1 s.

Claim 12. The process according to claim 1, wherein the mixing time
in the mixing means is from 0.007 to 0.1 s.

Claim 13. The process according to claim 1, wherein conversion,
based on amino groups in the amine employed to urethane groups, is at least
95% after departure from said residence-time reactor.

Claim 14. The process according to claim 1, wherein conversion,
based on amino groups in the amine employed to urethane groups, is not
more than 2% in said mixing means and at least 99.5% after departure from
said residence-time reactor.

Claim 15. The process according to claim 5, wherein the tube reactor
has a Bodenstein number of from 10 to 100.

Claim 16. The process according to claim 5, wherein the average
residence time in the tube reactor is from 10 seconds to 5 hours.

Claim 17. The process according to claim 5, wherein the average
residence time in the tube reactor is from 30 seconds to 10 minutes.

Claim 18. The process according to claim 5, wherein the total
residence time in the mixing means and the tube reactor is less than 5 hours.
Appeal 2011-007504
Application 12/065,680

4
Claim 19. The process according to claim 5, wherein the total
residence time in the mixing means and the tube reactor is less than 4 hours.

Claim 20. The process according to claim 5, wherein the total
residence time in the mixing means and the tube reactor is less than 3 hours.

Cited References

Frosch et al. US 4,847,408 Jul. 11, 1989
Otterbach et al. US 5,386,053 Jan. 31, 1995

E. Bruce Nauman, CHEMICAL REACTOR DESIGN, OPTIMIZATION, AND
SCALEUP 1, 25-28, 539-577 (2002).

Grounds of Rejection
Claims 1-20 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Otterbach in view of Frosch and Nauman.

FINDINGS OF FACT
The Examiner‟s findings of fact are set forth in the Answer at pages 4-
11. The following facts are highlighted.
1. Otterbach, Example 1, col. 9, discloses that

0.879 kg of urea, 0.805 kg of hexamethylene-1,6-diamine and
0.089 kg of n-butanol, as well as 3.333 kg of a product mixture
containing cleavage butanol, part of the reaction mixture from
the cleavage of urethane, containing the resultant by-products,
which principally comprised relatively high-molecular-weight
compounds containing isocyanurate, allophanate, urea and
polyurethane groups, and the top fraction from the purification
distillation of hexamethylene diisocyanate, were added per hour
at 220°-230°C. and 12 bar into the first reactor of a three-stage
stirred reactor cascade fitted with heated columns and head
condensers and a pressure-retention means, containing a
mixture of hexamethylene-1,6-dibutylurethane and n-butanol in
Appeal 2011-007504
Application 12/065,680

5
addition to hexamethylene-oligourea-polybutylurethanes,
dibutyl carbonate and butyl carbamate. The resultant ammonia
escaping from the refluxing reaction mixture was removed via
the columns and freed virtually quantitatively from butanol in
the downstream condensers by fractional condensation.
[Emphasis added.]

2. Otterbach, col. 1, l. 46-col 2, l.3, discloses that
aliphatic and/or cycloaliphatic diurethanes and/or polyurethanes
are prepared by reacting primary aliphatic and/or cycloaliphatic
diamines and/or polyamines with O-alkyl carbamates in the
presence of alcohols in an amine NH2 group:carbamate:alcohol
ratio of from 1:0.8 to 10:0.25 to 50 at from 160° to 300° C. in
the presence or absence of catalysts.

…

According to EP-A-28 338 (U.S. Pat. No. 4,290,970),
aromatic diisocyanates and/or polyisocyanates are prepared by
a two-step process in which, in the first step, primary aromatic
diamines and/or polyamines are reacted with O-alkyl
carbamates in the presence or absence of catalysts and in the
presence or absence of urea and alcohol to give aryldi- and/or –
polyurethanes.

3. The Specification page 5, discloses that “[i]n the process of the
invention the reactant streams are mixed in a suitable, special
mixing means which is characterized by low mixing times.”

4. The Specification page 6 discloses that

A preferred mixing means used is a mixing circuit, a stirred
vessel, a mixing pump or a jet mixing means, such as coaxial
mixing nozzles, Y- or T-mixer, or a vortex impinging jet
mixing configuration, preferably a mixing circuit, a stirred
vessel, a mixing pump or a jet mixing means.
Appeal 2011-007504
Application 12/065,680

6
When using a mixing circuit or a stirred vessel as mixing means
it is important to inject the amine solution at high speed. The
speeds are normally between 10 and 100 m/s, preferably
between 20 and 80 m/s.

It is preferred to use a mixing nozzle and a mixing pump as
mixing means. It is particularly preferred to use, as mixing
means, a mixing nozzle. In this case it is important that not only
the alcohol reactant stream but also the amine reactant stream
are introduced at high speed into the mixing nozzle. The speeds
are between 10 and 100 m/s, preferably between 20 and 80 m/s.

5. The Specification teaches a “tube reactor” (see Spec. 2, l. 39)
and mixing nozzles (Spec. 6, ll. 6-20.).
6. Frosch teaches that “cylindrical reaction chambers used may be,
for example, tube reactors without any fittings or moving parts inside the
reactor” (Frosch, col. 3, ll. 27-29).
7. Frosch teaches that the “streams of gas are generally introduced
into the tube reactor at one end thereof, for example by means of nozzles
arranged at one end of the tube reactor or by a combination of a nozzle and
an annular gap between the nozzle and the mixing tube” (Frosch, col. 3, ll.
33-37).
8. Nauman teaches that for “a flow reactor. . . . the mixing time
must be short compared with the mean residence time, else newly charged
material could flow out of the reactor before being thoroughly mixed with
the contents” (Nauman 25-26).

Appeal 2011-007504
Application 12/065,680

7
Discussion
ISSUE
The Examiner concludes that
Otterbach et al. teach the preparation of isocyanates with urea,
hexamethylene-1,6-diamine and butanol in a stirred reactor.
Frosch et al. teach a tube reactor for the preparation of
diisocyanates, comprises introducing reactants into the tube
reactor by means of nozzles arranged at one end of the tube
reactor or by a combination of nozzle and an annular gap
between the nozzle and the mixing tube.
However, one having ordinary skill in the art would have
recognized that the mixing with a specific mixing time in
Otterbach et al. would affect the yield as well as the cost
carrying out the production process.
It would have been obvious to one of ordinary skill in the
art at the time of the invention was made to modify the method
of Otterbach et al. such that the reaction process is carried out
in a tube reactor with a mixing equipment combination with the
guidelines taught by Frosch et al., and to arrive at applicants
process with a reasonable expectation of success. One having
ordinary skill in the art would have been motivated to do this to
optimize the yield relative to the cost of making the isocyanate.

(Ans. 6-7.)

Appellants argue that,
[T]he mixing means of the present invention is for
mixing. On the other hand, in Otterbach et al., the distillation
column is a reactor for conversion of amine groups into
urethane groups (column 9, lines 18-21). No partial conversion
in a mixing means is disclosed. Frosch et al. does not remedy
deficiencies of Otterbach et al.

(App. Br. 4.) “In Otterbach et al., no preliminary mixing is carried out.
Rather, all of the reactants are added into the first reactor of a three-
Appeal 2011-007504
Application 12/065,680

8
stage stirred reactor cascade, as demonstrated by the examples therein.”
(Id. at 3.) Appellants argue that a “three-stage stirred reactor cascade is not
a mixing means with at least one attached residence-time reactor. A three-
stage reactor cascade, although not disclosed for a urethanization reaction, is
exemplified as R1-R3 in Fig. 4 of US 7,179,935, copy of record.” (Id. at 4.)
The issue is: Does the cited prior art support the Examiner‟s
conclusion that the claimed subject matter is obvious, and does the prior art
teach a preliminary mixing step?

PRINCIPLES OF LAW
Construing a means-plus-function claim limitation is a two-step
process. First, the claim must be analyzed to determine whether the claim
language actually invokes the provisions of 35 U.S.C. § 112, sixth
paragraph. See Envirco Corp. v. Clestra Cleanroom, Inc., 209 F.3d 1360,
1364 (Fed. Cir. 2000) (“If a claim element contains the word „means‟ and
recites a function, th[e] court presumes that element is a means-plus-function
element under § 112, ¶ 6. . . . That presumption falls, however, if the claim
itself recites sufficient structure to perform the claimed function”). The
second step is to “determine what structures have been disclosed in the
specification that correspond to the means for performing that function.”
Kemco Sales, Inc. v. Control Papers Co., 208 F.3d 1352, 1361 (Fed. Cir.
2000).
“In rejecting claims under 35 U.S.C. § 103, the examiner bears the
initial burden of presenting a prima facie case of obviousness. Only if that
burden is met, does the burden of coming forward with evidence or
argument shift to the applicant.” In re Rijckaert, 9 F.3d 1531, 1532 (Fed.
Appeal 2011-007504
Application 12/065,680

9
Cir. 1993) (citations omitted). In order to determine whether a prima facie
case of obviousness has been established, we consider the factors set forth in
Graham v. John Deere Co., 383 U.S. 1, 17 (1966): (1) the scope and content
of the prior art; (2) the differences between the prior art and the claims at
issue; (3) the level of ordinary skill in the relevant art; and (4) objective
evidence of nonobviousness, if present.
“The combination of familiar elements according to known methods
is likely to be obvious when it does no more than yield predictable results.”
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007).
“[D]iscovery of an optimum value of a result effective variable in a
known process is ordinarily within the skill of the art.” In re Boesch, 617
F.2d 272, 276 (CCPA 1980).
“[T]he discovery of an optimum value of a variable in a known
process is normally obvious.” Exceptions to this rule include (1) the results
of optimizing a variable were unexpectedly good and (2) the parameter
optimized was not recognized in the prior art as one which would affect the
results. In re Antonie, 559 F.2d 618, 620 (CCPA 1977).

ANALYSIS
We agree with the Examiner‟s fact finding, statement of the rejection
and responses to Appellants‟ arguments as set forth in the Answer. We find
that the Examiner has provided evidence to support a prima facie case of
obviousness. We provide the following additional comment.
Appellants argue that the cited references do not teach a preliminary
mixing step. (App. Br. 3.) Appellants argue that “A three-stage stirred
reactor cascade is not a mixing means with at least one attached residence-
Appeal 2011-007504
Application 12/065,680

10
time reactor. A three-stage reactor cascade, although not disclosed for a
urethanization reaction, is exemplified as R1-R3 in Fig. 4 of US 7,179,935,
copy of record.” (App. Br. 4.) We are not persuaded.
The verb “mix” means “to combine or blend into one mass or
mixture.”
1
The claim uses the mean-plus-function language for the noun
“mixing means.” We look to the Specification to determine what structures
have been disclosed in the Specification that correspond to the means for
performing the function of mixing. One such means is a tube reactor,
taught as one of the means in the Specification (FF 5) and taught by Frosch
as a known type of reactor with mixing nozzles for forming diisocyanantes
(FF 6). In addition, Appellants have failed to provide evidence that the
amine and alcohol reactants of Otterbach are not combined or mixed, or that
a “stirred reactor cascade” as disclosed in Otterbach is not a suitable mixing
means for the claimed reaction.
As indicated by the Examiner (Ans. 7), Otterbach, Example 1
discloses mixing or combining an amine with an alcohol as claimed in a
stirred reactor cascade. (Col. 9, ll. 5-25.) We therefore agree with the
Examiner that the
claim language does not require preliminary mixing for the
reaction process. Even if it is there, the cited prior art already
suggested mixing all the reactants in the first step, before the
reaction starts [see example 1], this step can be interpreted as a
preliminary mixing and with a mixing device with certain
residence time.

1 The Free Dictionary. http://the freedictionary.com/mix

Appeal 2011-007504
Application 12/065,680

11
(Ans. 7.)
Nauman teaches that it is well known to those of ordinary skill in the art
to optimize “residence time [see pages 539, 540,576 and 577 in chapter 15]
and mixing time [see pages 25-28, in section 1.5 in chapter 1] in chemical
reactors designs, optimization and scale up.” (Ans. 5.) Nauman expressly
teaches the desirability of mixing, teaching that for “a flow reactor. . . . the
mixing time must be short compared with the mean residence time, else
newly charged material could flow out of the reactor before being
thoroughly mixed with the contents” (Nauman 25-26; FF 8).
“[T]he discovery of an optimum value of a variable in a known
process is normally obvious.” Exceptions to this rule include (1) the results
of optimizing a variable were unexpectedly good and (2) the parameter
optimized was not recognized in the prior art as one which would affect the
results. In re Antonie, 559 F.2d at 620. Appellants have failed to provide
evidence that one of ordinary skill in the art would not have been led by
Nauman to optimize the mixing and reaction times using known mixing
means such as a tube reactor or that these parameters optimized were not
recognized in the prior art as one which would affect the results.
Appellants argue that
the Comparative Example herein, as described in the
specification at page 15, lines 12-22, exemplifies the same
three-stage stirred reactor cascade as described in Otterbach et
al, which required an average residence time of approximately
five hours for conversion of all the amine. In the Inventive
Example, as described in the specification at page 14, line 34 to
page 15, line 3, the average residence time for complete
conversion of the amine was approximately four hours.

Appeal 2011-007504
Application 12/065,680

12
(App. Br. 4.)
However, Appellants provide no evidence that the comparative
example, or Example 1 of Otterbach which discloses the claimed mixing
step, does not result in a product “wherein conversion, based on amino
groups in the amine employed to urethane groups, is not more than 10% in
said mixing means.” Moreover, Claim 1 does not recite a specific residence
time and therefore the claimed process does not distinguish between the time
obtained in the comparative example in the Specification, page 15, from that
of the invention disclosed in the Specification or the process of Example 1 of
Otterbach.
The rejection of claim 1 is affirmed.
Appellants argue claims 2, 3, 6, 10-12 and 15-20 separately. (App.
Br. 6-9.)
With respect to claims 2, and 10, Frosch discloses the use of mixing
nozzles for streams of gas introduced into a tube reactor. (FF 7; Ans. 5.)
Appellants have failed to provide evidence that that gas streams from mixing
nozzles are not jet mixing means or coaxial mixing nozzles, as claimed.
With respect to claim 3, 11, 12, and 16 to 20, the Examiner relies on
Nauman for the disclosure that it is well known to those of ordinary skill in
the art to optimize “residence time [see pages 539, 540,576 and 577 in
chapter 15] and mixing time [see pages 25-28, in section 1.5 in chapter 1] in
chemical reactors designs, optimization and scale up.” (Ans. 5.) Appellants
have failed to provide evidence that one of ordinary skill in the art would not
have been led by Nauman to optimize the mixing and reaction times or that
these parameters optimized were not recognized in the prior art as one which
would affect the results.
Appeal 2011-007504
Application 12/065,680

13
With respect to claim 6 and 15, Appellants argue that the reactor of
Otterbach has a Bodenstein number of 3. A Bodenstein number is used in
mass transfer in general and diffusion in reactors calculations in particular,
providing a residence-time distribution. It is normally defined in the
following form
2
:

Where:
Dv,a = effective axial diffusivity
L = reactor length
V = velocity
The Examiner finds that “Bodenstein number is related to physical
property of the reactor and their conditions. The above cited references teach
the conditions in the reactor are optimizable. Therefore, Bodenstein number
is invariably part of the disclosed processes.” (Ans. 6.) Appellants have
failed to provide evidence or supporting calculations of the Bodenstein
number of Otterbach and have failed to establish with supporting evidence
that one of ordinary skill in the art would not have recognized that the
Bodenstein number of the tube reactor of Frosh is an optimizable variable
known to those of ordinary skill in the art.
In view of the above, the rejection of the dependent claims is also
affirmed.

2 http://www.processassociates.com/process/dimen/dn_bod.htm
Appeal 2011-007504
Application 12/065,680

14
CONCLUSION OF LAW
The cited references support the Examiner‟s obviousness rejection
which has not been rebutted with a preponderance of the evidence. The
rejection is affirmed for the reasons of record.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

cdc