U.S. patent application number 10/714711 was filed with the patent office on 2004-06-17 for process for the preparation of isoolefin copolymers.
Invention is credited to Bohnenpoll, Martin, Ismeier, Jurgen, Krauss, Hans Ludwig, Langstein, Gerhard, Resendes, Rui.
Application Number | 20040116627 10/714711 |
Document ID | / |
Family ID | 7696073 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040116627 |
Kind Code |
A1 |
Langstein, Gerhard ; et
al. |
June 17, 2004 |
Process for the preparation of isoolefin copolymers
Abstract
The present invention provides a novel process for the
preparation of isoolefin copolymers in the presence of zirconium
halides and/or hafnium halides and organic acid halides, in
particular for the preparation of butyl rubbers, as well as
isoolefin copolymers constructed of isobutene, isoprene and
optionally further monomers.
Inventors: |
Langstein, Gerhard; (Kurten,
DE) ; Ismeier, Jurgen; (Forstinning, DE) ;
Bohnenpoll, Martin; (Leverkusen, DE) ; Krauss, Hans
Ludwig; (Bamberg, DE) ; Resendes, Rui;
(Sarnia, CA) |
Correspondence
Address: |
BAYER POLYMERS LLC
100 BAYER ROAD
PITTSBURGH
PA
15205
US
|
Family ID: |
7696073 |
Appl. No.: |
10/714711 |
Filed: |
November 17, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10714711 |
Nov 17, 2003 |
|
|
|
10222378 |
Aug 16, 2002 |
|
|
|
6677421 |
|
|
|
|
Current U.S.
Class: |
526/90 |
Current CPC
Class: |
C08F 210/12 20130101;
C08F 210/12 20130101; C08F 2500/17 20130101; C08F 4/16 20130101;
C08F 4/00 20130101; C08F 210/12 20130101; C08F 236/08 20130101;
C08F 210/12 20130101 |
Class at
Publication: |
526/090 |
International
Class: |
C08F 002/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 21, 2001 |
DE |
10140859.5 |
Claims
What is claimed is:
1. A process for the preparation of isoolefin copolymers in the
presence of zirconium halides and/or hafnium halides, comprising
the step of polymerizing monomers in the presence of organic acid
halides.
2. A process according to claim 1, wherein said organic acid halide
corresponds to the general formula (I) R--COX (I), wherein R is
selected from the group consisting of C.sub.1-C.sub.18-alkyl,
C.sub.3-C.sub.18-cycloalkyl and C.sub.6-C.sub.24-cycloaryl, and X
may be fluorine, chlorine, bromine or iodine.
3. A process according to claim 1 wherein the concentration of the
organic acid halide in the reaction medium is within the range of 1
to 500 ppm.
4. A process according to claim 1, wherein said zirconium halide is
ZrCl.sub.4 and said hafnium halide is HfCl.sub.4.
5. A process according to claim 1, wherein isobutene is
copolymerized with isoprene and optionally further monomers.
6. A process according to claim 1, wherein AlCl.sub.3 or a catalyst
system which is preparable from AlCl.sub.3 is additionally
utilized.
7. A mixture of zirconium halide and/or hafnium halide and organic
acid halide corresponding to the general formula (I) R--COX (I),
wherein R is selected from the group consisting of
C.sub.1-C.sub.18-alkyl, C.sub.3-C.sub.18-cycloalkyl and
C.sub.6-C.sub.24-cycloaryl, and X may be fluorine, chlorine,
bromine or iodine.
8. A catalyst comprising a mixture of zirconium halide and/or
hafnium halide and organic acid halide corresponding to the general
formula (I) R--COX (I), wherein R is selected from the group
consisting of C.sub.1-C.sub.18-alkyl, C.sub.3-C.sub.18-cycloalkyl
and C.sub.6-C.sub.24-cycloaryl, and X may be fluorine, chlorine,
bromine or iodine.
9. A polymer which is prepared by the polymerization of monomers in
the presence of i) zirconium halides and/or hafnium halides, and
also ii) organic acid halides.
10. A polymer according to claim 9, wherein said organic acid
halide corresponds to the general formula (I) R--COX (I), wherein R
is selected from the group consisting of C.sub.1-C.sub.18-alkyl,
C.sub.3-C.sub.18-cycloalkyl and C.sub.6-C.sub.24-cycloaryl, and X
may be fluorine, chlorine, bromine or iodine.
11. A polymer according to claim 9, wherein the concentration of
the organic acid halide in the reaction medium is within the range
of 1 to 500 ppm.
12. A polymer according to claim 9, wherein said zirconium halide
is ZrCl.sub.4 and said hafnium halide is HfCl.sub.4.
13. A polymer according to claim 9, wherein isobutene is
copolymerized with isoprene and optionally further monomers.
14. A polymer according to claim 9, wherein AlCl.sub.3 or a
catalyst system which is preparable from AlCl.sub.3 is additionally
utilized.
15. A polymer according to claim 9, comprising up to 30 mol %
isoprene.
16. A molded body comprising a polymer which is prepared by the
polymerization of monomers in the presence of i) zirconium halides
and/or hafnium halides, and also ii) organic acid halide.
Description
FIELD OF THE INVENTION
[0001] The present invention provides a novel process for the
preparation of isoolefin copolymers in the presence of zirconium
halides and/or hafnium halides and organic acid halides, in
particular for the preparation of higher isoprene-containing butyl
rubbers, as well as isoolefin copolymers constructed of isobutene,
isoprene and optionally further monomers.
BACKGROUND OF THE INVENTION
[0002] The process currently used for the preparation of butyl
rubber is known, for example, from Ullmann's Encyclopedia of
Industrial Chemistry, Vol. A 23, 1993, pp. 288 to 295. The cationic
copolymerization of isobutene with isoprene in the slurry process
with methyl chloride as the process solvent is carried out with
aluminum trichloride as an initiator with the addition of small
quantities of water or hydrogen chloride at -90.degree. C. The low
polymerization temperatures are necessary in order to obtain
molecular weights sufficiently high for rubber applications.
[0003] It is in principal possible to compensate for the molecular
weight-lowering (=regulating) effect of the dienic comonomers by
even lower reaction temperatures. However, in this case there is a
more marked occurrence of the side reactions which lead to gel
formation. Gel formation at reaction temperatures of around
-120.degree. C. and possible ways of reducing it are described
(q.v. W. A. Thaler, D. J. Buckley, Sr., Meeting of the Rubber
Division, ACS, Cleveland, Ohio, May 6 to 9, 1975, published in
Rubber Chemistry & Technology 49, 960 to 966 (1976)). On the
one hand, handling of the auxiliary agents which are necessary
here, such as CS.sub.2, is difficult, and they must furthermore be
utilized at relatively high concentrations.
[0004] The gel-free copolymerization of isobutene with various
comonomers at temperatures of around -40.degree. C. with the use of
preformed vanadium tetrachloride to obtain products having
molecular weights sufficiently high for rubber applications is
additionally known (EP-A1-0 818 476).
[0005] U.S. Pat. No. 2,682,531 describes zirconium
tetrachloride-ether complexes and the use thereof as catalysts for
the polymerization of, inter alia, isoolefins. It is emphasized in
column 2, line 20 et seq. that the use of zirconium tetrachloride
alone leads to unsatisfactory results. The ether which is
preferably used is .beta.,.beta.'-dichloroeth- yl ether, a
carcinogen. The diphenyl ether which is likewise listed as an
example results in poorly soluble complexes which have sufficient
activity only at very high dosing levels. Diethyl ether (named
specifically in the patent as a possible ether) results in
completely ineffective complexes.
[0006] The older application DE-A-1 00 42 118 describes a process
for the preparation of isoolefin copolymers with the use of
initiator systems prepared from zirconium halides or hafnium
halides in the presence of organic nitro compounds. While these
initiator systems permit the preparation of highly unsaturated
butyl rubbers, for example, they have the disadvantage that it is
very difficult in practice to use organic nitro compounds on a
large industrial scale on account of the associated explosion
hazard.
SUMMARY OF THE INVENTION
[0007] The object of the present invention was to provide a process
for the preparation of high molecular weight low-gel isoolefin
copolymers, in particular, for the preparation of butyl rubbers
having more than 2% isoprene in the polymer without the use of
nitro compounds.
[0008] The present invention provides a process for the preparation
of high molecular weight isoolefin copolymers in the presence of
zirconium halides and/or hafnium halides, wherein the
polymerization takes place in the presence of organic acid
halides.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The process is preferably utilized with isoolefins having 4
to 16 carbon atoms and dienes which are copolymerizable with the
isoolefins, optionally in the presence of further monomers which
are copolymerizable with the monomers. More preferably, isobutene
and isoprene are utilized, optionally in the presence of further
monomers which are copolymerizable with these.
[0010] The process is preferably carried out in a solvent which is
suitable for cationic polymerization, such as halogenated and
non-halogenated hydrocarbons or mixtures thereof, in particular
chloroalkanes and chloroalkane/alkane mixtures, more preferably,
methyl chloride and methylene chloride or mixtures thereof with
alkanes.
[0011] The zirconium halide and/or hafnium halide is preferably
mixed with the organic acid halide in the absence of the
monomer.
[0012] The organic acid halides which are utilized are commonly
known and are available generally. The acid halides preferably used
according to the present invention are defined by the general
formula (I)
R--COX (I),
[0013] wherein R is selected from the group of
C.sub.1-C.sub.18-alkyl, C.sub.3-C.sub.18-cycloalkyl and
C.sub.6-C.sub.24-cycloaryl.
[0014] C.sub.1-C.sub.18-alkyl is understood to mean any of the
linear or branched alkyl radicals having 1 to 18 C atoms, which are
known to those skilled in the art, such as methyl, ethyl, n-propyl,
i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl,
hexyl and the further homologues, which may for their part be in
turn substituted. Here, alkyl, as well as cycloalkyl or aryl, such
as benzyl, trimethylphenyl, ethylphenyl, are in particular,
considered as substituents. Linear alkyl radicals having 1 to 18 C
atoms, more preferably methyl, ethyl and benzyl, are preferred.
[0015] C.sub.6-C.sub.24-aryl is understood to mean any of the
mononuclear or polynuclear aryl radicals having 6 to 24 C atoms,
which are known to those skilled in the art, such as phenyl,
naphthyl, anthracenyl, phenanthracenyl, and fluorenyl, which may
for their part in turn be substituted. Here, alkyl, as well as
cycloalkyl or aryl, such as toloyl and methylfluorenyl, are in
particular considered as substituents. Phenyl is preferred.
[0016] C.sub.3-C.sub.18-cycloalkyl is understood to mean any of the
mononuclear or polynuclear cycloalkyl radicals having 3 to 18 C
atoms, which are known to those skilled in the art, such as
cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,
cyclooctyl and the further homologues, which may for their part be
in turn substituted. Here, alkyl, as well as cycloalkyl or aryl,
such as benzyl, trimethylphenyl, ethylphenyl, are, in particular,
considered as substituents. Cyclohexyl and cyclopentyl are
preferred.
[0017] The radical X stands for the halogens: fluorine, chlorine,
bromine and iodine. X preferably stands for chlorine.
[0018] The concentration of the organic acid halide in the reaction
medium is preferably within the range 1 to 500 ppm, more preferably
within the range 10 to 100 ppm. The molar ratio of acid halide to
zirconium and/or hafnium is preferably within the range 0.5 to 50,
more preferably within the range 1 to 30 and most preferably within
the range 2 to 10.
[0019] The polymerization of the monomers generally takes place in
a cationic manner at temperatures within the range -120.degree. C.
to +20.degree. C., preferably within the range -95.degree. C. to
-20.degree. C., and at pressures within the range 0.1 to 4 bar.
[0020] Suitable zirconium halides and/or hafnium halides are, for
example, zirconium dichloride, zirconium trichloride, zirconium
tetrachloride, zirconium oxydichloride, zirconium tetrafluoride,
zirconium tetrabromide and zirconium tetraiodide, hafnium
dichloride, hafnium trichloride, hafnium oxydichloride, hafnium
tetrafluoride, hafnium tetrabromide and hafnium tetraiodide and
hafnium tetrachloride. Zirconium halides and/or hafnium halides
having sterically demanding substituents such as, for example,
zirconocene dichloride or bis-(methylcyclopentadienyl)zirconium
dichloride, are generally unsuitable. Zirconium tetrachloride is
preferably utilized. This may be utilized advantageously in the
form of a solution in an anhydrous, acid-free alkane or
chloroalkane or a mixture of the two, having a zirconium
concentration of less than 4 wt. %. It may be advantageous to store
(age) the zirconium solution at room temperature or below for a
period of from a few minutes to 1,000 hours before utilization. It
may be advantageous to carry out this aging with the action of
light.
[0021] It may, furthermore, be advantageous to utilize mixtures of
the catalyst system according to the present invention with
conventional catalysts such as AlCl.sub.3 and catalyst systems
which are preparable from AlCl.sub.3, diethyl aluminum chloride,
ethyl aluminum chloride, titanium tetrachloride, tin tetrachloride,
boron trifluoride, boron trichloride, vanadium tetrachloride or
methyl alumoxane, in particular AlCl.sub.3 and catalyst systems
which are preparable from AlCl.sub.3. This combination is also
provided by the invention.
[0022] When preparing such mixtures, the molar ratio of Lewis acid:
zirconium and/or hafnium may be within the range 99:1 to 1:99,
preferably within the range 99:1 to 1:1, more preferably within the
range 20:1 to 5:1.
[0023] The molar ratio of acid halide to zirconium and/or hafnium
in the case of such mixtures is preferably within the range 0.5 to
50, more preferably within the range 1 to 30 and most preferably
within the range 2 to 10.
[0024] It may be advantageous to add to the catalyst system small
quantities of water, alcohols, an alkyl halide or
halohydrocarbon.
[0025] The polymerization may be carried out in both a continuous
and also a discontinuous method. In a continuous method, the
process is preferably carried out with the following three feed
streams:
[0026] 1. Solvent/diluent +isoolefin (preferably isobutene)
[0027] 2. Diene (preferably isoprene)
[0028] 3. Zirconium halide and/or hafnium halide (preferably
ZrCl.sub.4 in solvent)+organic acid halide.
[0029] In a discontinuous method the process may, for example, be
carried out as follows:
[0030] The reactor, which is pre-cooled to reaction temperature, is
charged with the solvent or diluent and the monomers. The initiator
together with the acid halide in the form of a diluted solution is
then pumped-in such as to allow problem-free removal of the heat of
polymerization. The progress of the reaction can be tracked by
means of the heat generation. The catalyst solution may also be
added portion-wise through a lock.
[0031] All operations are carried out under a protective gas. After
the end of polymerization the reaction is terminated with a
phenolic antioxidant such as, for example,
2,2'-methylene-bis-(4-methyl-6-tert.-bu- tylphenol), dissolved in
ethanol.
[0032] The process according to the present invention enables high
molecular weight isoolefin copolymers to be prepared. The double
bonds are determined by the quantity of incorporated diene. The
molecular weights (M.sub.v) generally range from 300-1200 kg/mol
(depending on the isoprene content and the reaction temperature),
the polymers have a very low gel content.
[0033] The polymers which are obtainable are suitable for the
production of molded bodies of all kinds, in particular tire
components, most particularly so-called inner liners, as well as
so-called technical rubber goods such as stoppers, damping
elements, profiles, films, coatings. For these purposes, the
polymers are utilized pure or in mixture with other rubbers such as
BR, HNBR, NBR, SBR, EPDM or fluorinated rubbers.
[0034] The Examples which follow are provided for the purpose of
illustrating the present invention:
EXAMPLES
[0035] Experimental Details
[0036] The gel contents were determined in toluene after a
dissolution time of 24 hours at 30.degree. C. at a sample
concentration of 12.5 g/l. The insoluble constituents were
separated by ultracentrifuging (1 hour at 20,000 rpm and 25.degree.
C.). Samples having a high gel content were checked in
o-dichlorobenzene at 140.degree. C.
[0037] The solution viscosity .theta. of the soluble constituents
was determined in toluene at 30.degree. C. by Ubbelohde capillary
viscometry.
[0038] The molecular weight M.sub.v calculated from the limit
viscosity was determined in accordance with the following formula:
1n (M.sub.v)=12.48+1.565 1n.theta..
[0039] The Mooney value was determined at 125.degree. C. after a
measuring time of 8 minutes.
[0040] Argon 4.8 (from Linde) was used as the protective gas.
[0041] The monomer incorporation and the "branching point".sup.1
were determined by means of high-field proton resonance. 1 J. L.
White, T. D. Shaffer, C. J. Ruff, J. P. Cross: Macromolecules
(1995) 28, 3290
[0042] The isobutene (from Gerling+Holz, Germany, 2.8 quality)
utilized in the polymerizations was dried by passing through a
column packed with sodium on aluminum oxide (content: 10%).
[0043] The isoprene (from Acros, 99%) used was filtered under argon
through a dried aluminum oxide column to remove the stabilizer,
distilled over calcium hydride under an argon atmosphere, and
utilized in this form for the polymerization. The water content was
25 ppm.
[0044] The methyl chloride (from Linde, 2.8 quality) used was
purified by passing through an activated charcoal column and a
further column packed with Sicapent, and was utilized in this
form.
[0045] The methylene chloride (from Merck, analytical grade: ACS,
ISO) was dried by distillation over phosphorus pentoxide under an
argon atmosphere.
[0046] The acetyl chloride (from Aldrich, 99+%) was distilled under
argon.
[0047] The zirconium tetrachloride (>=98%) used was obtained
from Fluka.
[0048] The aluminum trichloride (98.5%) used was obtained from
Janssen Chimica.
[0049] A cooled solution of 2 g Irganox 1010 (from Ciba) in 250 ml
ethanol was used to terminate the polymerizations.
Example 1
Preparation of the Initiator
[0050] 0.233 g ZrCl.sub.4 were weighed into a Schlenk-type vessel
under argon protective gas, and 60 .mu.l acetyl chloride were
added. 100 g methyl chloride were then condensed-in at 40.degree.
C., and stirring took place at this temperature for 4 hours. The
initiator solution is slightly cloudy. The initiator may be used
thus or in a diluted form.
Example 2
Polymerization, Initiator Solution Metered-in
[0051] 2a
[0052] 700 g dry methyl chloride and 300 g isobutene were condensed
at -90.degree. C. into a Schlenk-type four-neck flask. 24.5 g
isoprene were added in liquid form. The monomer feed was then
temperature-controlled to -80.degree. C. The initiator described in
Example 1 was transferred into a dropping funnel cooled to
-40.degree. C. The polymerization was carried out by slow dropwise
introduction of the initiator solution, such that the temperature
could be maintained at -80.degree. C. 22 ml of the initiator
solution were dropped in within 17 minutes. The initially milky
suspension agglomerated so strongly after 16 minutes that the
internal temperature could no longer be maintained and rose to
-75.2.degree. C. The reaction was terminated. 54.6 g dry polymer
having a Staudinger index of 1.7 dl/g and a gel content of 0.9%
could be obtained. The 1,4-incorporated isoprene content was 2.4
mol %.
[0053] 2b
[0054] 700 g dry methyl chloride and 300 g isobutene were condensed
at -90.degree. C. into a Schlenk-type four-neck flask. 32.7 g
isoprene were added in liquid form. The monomer feed was then
temperature-controlled to -90.degree. C. An initiator solution
prepared in a manner analogous to Example 1, but stirred for only 2
hours at -40 C., was transferred into a dropping funnel cooled to
-40.degree. C. The polymerization was carried out by slow dropwise
introduction of the initiator solution, such that the temperature
could be maintained at -90.degree. C. 44 ml of the initiator
solution were dropped in within 30 minutes. The initially milky
suspension agglomerated so strongly that the internal temperature
rose to -89.4.degree. C. The reaction was terminated after 30 min.
25.9 g dry polymer having a Staudinger index of 1.71 dl/g and a gel
content of 0.9% could be obtained. The 1,4-incorporated isoprene
content was 3.84 mol %.
[0055] 2c
[0056] 700 g dry methyl chloride and 300 g isobutene were condensed
at -90.degree. C. into a Schlenk-type four-neck flask. 40.9 g
isoprene were added in liquid form. The monomer feed was then
temperature-controlled to -90.degree. C. An initiator solution
prepared in a manner analogous to Example 1, but stirred for only 2
hours at -40.degree. C., was transferred into a dropping funnel
cooled to -40.degree. C. The polymerization was carried out by slow
dropwise introduction of the initiator solution, such that the
temperature could be maintained at -90.degree. C. 56 ml of the
initiator solution were dropped in within 30 minutes. The initially
milky suspension rapidly became very cloudy and agglomerated after
42 ml, and the internal temperature rose to -89.7.degree. C. The
reaction was terminated after 27 min. 32.6 g dry polymer having a
Staudinger index of 1.47 dl/g and a gel content of 0.8% could be
obtained. The 1,4-incorporated isoprene content was 4.77 mol %.
[0057] 2d
[0058] 700 g dry methyl chloride and 300 g isobutene were condensed
at -90.degree. C. into a Schlenk-type four-neck flask. 8.2 g
isoprene were added in liquid form. The monomer feed was then
temperature-controlled to -90.degree. C. An initiator solution
prepared at -40.degree. C. from 268 mg ZrCl.sub.4, 5 ml benzoyl
chloride and 100 g methyl chloride was transferred into a dropping
funnel cooled to -40.degree. C. after aging for 30 minutes. The
polymerization was carried out by slow dropwise introduction of the
initiator solution, such that the temperature could be maintained
at -90.degree. C. 82 ml of the initiator solution were dropped in
within 48 minutes. The initially milky suspension agglomerated
after 20 ml, and the internal temperature rose to -89.6.degree. C.
26.5 g dry polymer having a Staudinger index of 2.44 dl/g and a gel
content of 0.8% could be obtained.
Example 3
Polymerization, Initiator Solution Added Batchwise
[0059] 3a
[0060] 460 g dry methyl chloride and 36 g isobutene were condensed
at -90.degree. C. into a Schlenk-type four-neck flask. 2.55 g
isoprene were added in liquid form. The monomer feed was then
temperature-controlled to -90.degree. C. An initiator solution
prepared in a manner analogous to Example 1 was transferred into a
dropping funnel cooled to -40.degree. C. The polymerization was
initiated by addition of the initiator solution by way of a
Schlenk-type tube. The temperature rose to -86.5.degree. C. The
reaction was terminated after 5 min. 14.1 g dry polymer having a
Staudinger index of 0.8 dl/g and a gel content of 0.4% could be
obtained. The 1,4-incorporated isoprene content was 2.12 mol %.
[0061] Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood
that such detail is solely for that purpose and that variations can
be made therein by those skilled in the art without departing from
the spirit and scope of the invention except as it may be limited
by the claims.
* * * * *