~2ûJ243
ME:THOD F~R PRÇ)L)UC lNl; HIGHLY ACTIVE, STABLE METALLOCENE
C~TALYST SYSTEMS, AND FORMULATIONS PROL~U~ H~ Ry
Backqround of the Invention
Metallocene catalyst systems are
increasingly gaining in importance as a new generation
of catalyst systems for the production of polyolefins
("Single Site Catalysts"). As is already known from
classical Ziegler-Natta catalysis, these new catalysts
essentially consist of a transition-metal compound as
a catalyst and a cocatalyst component, for example, an
alkylaluminoxane, in particular, methylaluminoxane.
Cyclopentadienyl, indenyl, or fluorenyl derivatives of
group IVA of the Periodic Table of the Elements are
preferably used as the transition metal compound. In
contrast to conventional Ziegler-Natta catalysts, such
systems have, in addition to a high activity and
productivity, not only the capability of a specific
control of product characteristics as a function of
the components used and the reaction conditions, but,
moveover, they open up access to previously unknown
polymer structures with very promising characteristics
with regard to technical applications.
In the literature, a large number of
publications have appeared having as an object the
production of special polyolefins with such catalyst
systems. What is disadvantageous in almost all cases,
however, is the fact that to attain acceptable
productivities, a high excess of alkylaluminoxanes,
based on-the transition metal component, is required
(usually, the ratio of aluminum, in the form of
2~0~243
1 aluminoxane, to transition metal is approximately
1000:1). Due to the high price of the
alkylaluminoxanes, on the one hand, and due to the
additional polymer work-up steps ("dea~hing stepsn),
required in some cases, on the other hand, a polymer
production on a technical scale and on the basis of
such catalyst systems would frequently be
uneconomical. In addition, there is the fact that the
solvent toluene, frequently used for the formulation
of alkylaluminoxanes, in particular,
methylaluminoxane, is increasingly undesired for
reasons of the storage stability of highly
concentrated formulations (strong tendency to gel
formation of the alllm;noxane solutions) and for
toxicological reasons, with respect to the application
range of the polyolefins that result in the long run.
These catalyst systems or their formulations
are very sensitive subs~ances that undergo losses in
polymerization activity within a few hours or days.
Due to the high price of these modern
catalyst systems, such activity losses are not
acceptable. For economic reasons, therefore, there
has been a need for catalysts or catalyst systems
- which, after production, remain highly active for a
longer period of time or even increase in acti~ity.
According to World Patent No. 93/23439, the
stability of metallocene catalyst systems is attained
by a comprehensive variation of the preparation
conditions, in particular, temperature treatment.
3o
22~)2~3
--3--
1 This procedure is expensive, on the one
hand, and cannot generally be used because of the
sensitivity of the systems, on the other hand.
The goal of the present invention,
therefore, is to overcome these disadvantages and to
develop homogeneous formulations of metallocene-based
catalyst systems that at least retain their high
polymerization activity over a long period of time.
Brief SummarY of the Invention
Surprisingly, it has been discovered that
the polymerization activity of metallocene catalyst
systems in the form of paraffin-containing, liquid or
solid formulations can be stabilized permanently. The
definition formulation, therefore, comprises catalyst
systems in high-boiling hydrocarbons (paraffins) of a
consistency which is oily or waxy at room temperature,
in which the components are dissolved, suspended, or
dispersed by means of suitable mixing devices.
An object of the invention is therefore a
method for the production of homogeneous mixtures,
consisting essentially of at least one metallocene, at
least one cocatalyst, and a formulation medium,
wherein the preparation of the catalyst component,
A) takes place directly in the formulation
medium according to methods which are, in fact, known;
- or
B) the metallocene-based catalyst components
are prepared and isolated separately and then
22u~3243
1 suspended, dispersed, or dissolved in the formulation
medium; or
C) a solution of the metallocene-based
catalyst component, produced according to known
methods, in a low-boiling solvent, is introduced, in a
first step, into the formulation medium, and in a
second step, the l.ow-boiling solvent is removed,
D) optionally in the presence of any of the
customary inorganic or organic carrier materials,
auxiliaries, additives, and/or accessory agents.
Another object of the invention refers to
the formulations produced in accordance with the
method of the invention.
Other objects of the invention are
characterized by the claims.
Detailed Description of the Invention
The formulation media useful according to
this invention include all natural or synthetic,
commercially available long-chain, optionally
branched, liquid or solid hydrocarbons with boiling
points above 150~C, preferably above 200~C, and
viscosities of at least 1 Pa-sec at 25~C.
These compounds include the product groups
of the so-called white mineral oils, e.g. Witco White
Mineral Oil Parol~ (trademark of Witco Polymers ~
Resins B.V., Netherlands), petrolatum (Vaseline), and
paraffinic waxes, e.g., Terhell~ (Schumann Company).
2~0U24~
--5--
1 The hydrocarbon used does not depend on the
organometallic compound but is determined mainly by
practical requirements of future applications.
Compounds of the elements of Groups IIA,
5 IIIA, or IVA of the Periodic Table of the Elements,
preferably organoaluminum, organoboron, or
organomagnesium substances, alone or in mixtures, or
as a complex salt, are used as cocatalysts, in
accordance with the invention, such as RlR2R3Al,
RlR2R3B, and R1R2Mg, wherein Rl, R2, R3 are independently
of one another halogen, a heteroatom, or alkyl or
alkoxy containing up to 12 carbon atoms, for example:
tributylaluminum, triisobutylaluminum,
trihexylalllminl~m, trioctylaluminum, diethylaluminum
]5 chloride, ethylaluminum sesquichloride, ethylaluminum
dichloride, diisobutylaluminum chloride,
isobutylaluminum dichloride, diethylaluminum iodide,
diisobutyl hydride, diethylaluminum methoxide,
isoprenylaluminum, dimethylaluminum chloride,
methylalulllinoxane, methylaluminum sesquichloride,
tetraisobutyl dialuminoxane, trimethyl aluminum,
and/or triethylaluminum, preferably in mixtures with
at least one of the compounds diethylaluminum hydride,
hexaisobutyltetraluminoxane, diethyl
(dimethylethylsilanolato)aluminum,
diethyl(ethylmesthylsilanolato)aluminum,
diisobutyl(methylsilanolato)aluminum,
tridodecylaluminum, tripropylaluminum,
dipropylaluminum chloride, dibutylmagnesium,
butylethylmagnesium, butyloctylmagnesium,
22 ù~243
--6--
1 butyloctylmagnesium ethoxide, ethylalllminl-m
propoxychloride, triethylboron,
tris(pentafluorophenyl)borane, and their salts.
As a catalyst component, one can metallocene
compounds as described in European Patent Nos.
A-0,480,390, A-0,413,326, A-0,530,908, A-0,344,887,
A-0,420,436, A-0,416,815, A-0,520,732.
They are, in particular compounds of the
following general formula
QtcpRa)(cp~R~a)M(x)n (1)
whereln
Cp is a cyclopentadienyl, indenyl or fluorenyl
radical;
R and R' are the same or different and each is a Cl-C10
alkyl, phosphine, amine, Cl-C10 alkyl ether, or C6-ClO
aryl ether group with O<a~4 and O<a'<4;
Cp' is one of the groups Cp or
Cp~ is -NR~- wherein-R~ is an alkyl or aryl radical
and a=1, and
Q is a single bridge or multi bridges
(Rl-Z-R2) b
between Cp and Cp', wherein Rl and R2 are the same or
different and each is a hydrogen atom, Cl-C10 alkyl
group, or C6-C10 aryl group, and Z denotes carbon,
3~ silicon, or germanium, wherein b is 0, 1, 2, or 3,
22~iU24~
1 M is a transition metal of the groups 3 to 6 of the
Periodic Table of the Elements ~IUPAC notation), in
particular Zr or Hf,
X is halogen, in particular, Cl or Br, and
n is the oxidation number of M, reduced by 2.
In particular, the following compounds can
be used as bridged ligands, Q(CpRa)(Cp'R'a) in general
formula (1):
Dimethylsilylbis(1-indene),
dimethylsilylbis(l-cyclopentadiene), 2,2-propylbis(1-
indene),
2,2-propylbis(trismethylcyclopentadiene),
2,2-propylbis(5-dimethylamino-1-indene),
2,2-propylbis(6-dipropylamino-1-indene),
2,2-propylbis(4,7-bis(dimethylamino-1-indene)),
2,2-propylbis(5-diphenylphosphino-1-indene),
2,2-propylbis(4,5,6,7-tetrahydro-1-indene),
2,2-propylbis(4-methyl-1-indene), 2,2-propylbis(5-
methyl-1-indene),
2,2-propylbis(6-methyl-1-indene),2,2-propylbis(7-
methyl-l-indene),
2,2-propyl-bis(5-methoxy-1-indene),
2,2-propylbis(4,7-dimethoxy-1-indene),
2,2-propylbis(2,3-dimethyl-1-indene),
- 25 2,2-propylbis(4,7-dimethyl-1-indene),
2,2-propylbi~(1-cyclopentadiene),
2,2-propylbis(1-indene), diphenylmethylbis(1-indene),
diphenylmethylbis(l-cyclopentadiene), - -
diphenylmethylbis(l-indene),
3o
22i:)(i24~
--8--
1 diphenylsilylbis(l-indene)r diphenylsilylbis(1-
cyclopentadiene),
diphenylsilylbis(l-indene), ethylenebis(1-indene),
ethylenebis(trimethylcyclopentadiene),
ethylenebis(5-dimethylamino-1-indene),
ethylenebis(6-dipropylamino-1-indene),
ethylenebis(4,7-bisdimethylamino-1-indene),
ethylenebis(5-diphenylphosphino-1-indene),
ethylenebis(4,5,6,7-tetrahydro-1-indene),
ethylenebis(6-methyl-1-indene), ethylenebis(7-methyl-
1-indene),
ethylenebis(5-methoxy-1-indene),
ethylenebis(4,7-dimethoxy-1-indene),
ethylenebis(2,3-dimethyl-1-indene),
ethylenebis(4,7-dimethyl-1-indene), ethylenebis(9-
fluorene),
ethylenebis(1-cyclopentadiene), ethylenebis(1-indene).
As unbridged ligands (formula (1) with b =
0), preferably the following compounds can be used:
cyclopentadiene, fluorene, indene, and their
monoalkylated or multialkylated derivatives, wherein
- the alkyl radical can contain 1-10 ca~bon atoms. In
accordance with the invention, the following are
pre-ferred:
[bis(cyclopentadienyl)]zirconium dichloride,
[bis(methylcyclopentadienyl)~zirconium dichloride,
[bis(n-propylcyclopentadienyl)]zirconium dichloride,
[bis(isobutylcyclopentadienyl)]zirconium dichloride,
[bis(cyclopentylcyclopentadienyl)~zirconium
dichloride,
~2 ù~i243
1 [bis(benzylcyclopentadienyl)]zirconium dichloride,
[bis(octadecylcyclopentadienyl)3zirconium dichloride,
[bis(n-butylcyclopentadienyl)]titanium dichloride,
[bis(n-butylcyclopentadienyl)~zirconium dichloride,
[bis(n-butylcyclopentadienyl)]hafnium dichloride,
~bis(indenyl)]zirconium dichloride,
[bis(indenyl)]dimethylzirconium,
[bis(tetrahydroindenyl)]zirconium dichloride, [1,2-
ethylenebis(indenyl)]zirconium dichloride,
[1,2-ethylenebis(indenyl)hafnium dichloride,
[1,2-ethylenebis(tetrahydroindenyl)zirconium
dichloride,
[dimethylsilylbis(lH-inden-1-yl]zirconium dichloride,
[dimethylsilylbis(lH-inden-l-yl)]hafnium dichloride.
Porous oxides of one or more of the elements
of groups IIA, IIIA, or IVA of the Periodic Table of
the Elements, such as ZrO2, Tio2, B203, CaO, ZnO, BaO,
preferably aluminosilicates (zeolites), Al203 and MgO
and in particular, SiO2 (West German Patent No.
4,409,249), are useful as inorganic carrier materials
that can be.used in accordance with the invention.
Porous, partially polymeric compounds, such
as polyethylene, polypropylene, polystyrene, and-sugar
derivatives (starch, amylose, cyclodextrins), can be
taken into consideration as organic carrier materials
that can be used in accordance with the invention.
To prepare the formulations of the-
-invention, in accordance with the method of the
invention, there are basically different
possibilities, for example:
~20~)243
--10--
1 M1) Preparat_on of the metallocene-based
catalyst system in the dispersing /suspending medium
or solvent (paraffin), in accordance with the
lnvention.
M2) Dissolution, suspension, or dispersion
of already isolated metallocene-based catalyst
components in the dispersing medium or solvent
(paraffin), in accordance with the invention
M3) Mixing of nonaromatic solvent or
dispersing agent with a solution of the metallocene-
based catalyst components and subsequent separation of
the solvent by means of distillation, thus obtaining
the solutions, suspensions, or dispersions, in
accordance with the invention.
To prepare the formulations, the catalyst
components can be used in pure form as well a~ on a
suitable support material. If the catalyst components
are used in pure ~orm, the support material and
auxiliaries, additives, and accessory agents can be
added to the processing possibilities M1)-M3) at any
time.
The following examples illustrate the
synthesis of the claimed metallocene-catalyst systems
and their testing in the polymerization.
22 ~J~2i~3
--ll--
1 Synthesis Examples
Example 1
Methylaluminoxane in Witco Parol~ (trade name of Witco
Netherlands)
402 g of a toluene solution of MA0 (Al
total, 13.2%; Al as TMA, 3.19~) and 219 g Witco Parol~
were fed under nitrogen atmosphere to a 1-~ flask,
equipped with a thermometer and stirrer that moves
around the edges. The flask contents were heated in
an oil bath to a m~;ml~m 32~C and a vacuum was
applied. The distilled-off toluene was condensed in a
low-temperature trap. It was possible to strengthen
the vacuum with the declining toluene content of the
suspension. Toluene residues were distilled off at cl
mbar for 3 h.
A viscous and milky-turbid suspension was
obtained. The suspension wa~ neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 13.4%
Al as TMA: 1.5
Example 2
Methylaluminoxane in Witco Petroleum Jelly Snowwhite
MD~ (Vaseline, Witco Netherlands)
3o
~ ~ ù~2~3
l 130.1 g of a toluene solution of MA0
(Al total, 13.2; Al as TMA, 3.19%) and 85.1 g White
Petroleum Jelly Snowwhite MD~ were fed into a 500-mL
Schlenk tube, equipped with a stirrer, under a
protective nitrogen atmosphere. After heating to 55-
60~C in an oil bath, the mixture became homogeneous.
The toluene was distilled off in a vacuum and
condensed in a low-temperature trap. The vacuum was
continuously increased to below 1 mbar, and the bath
temperature was maintained at a maximum of 65~C.
After complete ~e-,loval of the toluene, a colorless,
homogeneous, waxlike mass was obtained, which flowed
at approximately 60~C.
The suspension was neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 12.0%
Al as TMA: 1.9%
ExamPle 3
Methylaluminoxane in paraffin wax
33.5 g Methylaluminoxane (solid) and 16.8 g
paraffin (Terhell 5605~, Schumann Company) were heated
under nitrogen in a round-bottomed flask with a
stirrer that moves around the edges. With a bath
temperature of 65-70~C, a turbid melt was obtained.
The melt was allowed to solidify while stirring and
then the melt was dissolved from the walls of the
~ ' IJ~.i243
.
-13-
1 flask. After cooling externally with dry ice, it was
possible to comminute the solid to a fine grain solid
which could be poured.
The powder, containing approximately 66%
MA0, was not pyrophoric or self-igniting.
Al total: 26.1
Al as TMA: 3.5
Example 4
Methylaluminoxane in Witco Parol~
26.3 g of a finely pulverized MA0 solid (Al
total, 39.2%) were stirred with 7.3 g white oil Witco
Parol~ under a protective argon atmosphere. A
colorless, waxlike mass was obtained.
The powder containing approximately 78~ MA0
was not pyrophoric or self-igniting and exhibited only
a moderate gas development upon contact with water.
Placed on moist filter paper, carbonization without
self-ignition was observed.
Al total: 30.1
Al as TMA: 3.6
Example 5
Dispersion of methylaluminoxane in petrolatum
(Vaseline)
Under a protective nitrogen atmosphere, 125
g of a toluene solution of MA0 (Al total, 13.2~; Al as
2~)2~3
-14-
l TMA, 3.19%) and 78.5 g petrolatum, white, German
Pharmacopoeia 10, VARH AB (Sch*m~nn Company) were fed
into a 500-mL Schlenk tube, equipped with a stirrer.
After heating to 55-60~, the toluene was distilled off
and condensed in a low-temperature trap. The vacuum
was continuously increased to below 1-mbar, and the
bath temperature was maintained at a m~;m1]m 65~C.
After complete le...Jvdl of the toluene, a colorless,
homogeneous dispersion was obtained, which could flow
at above approximately 60~C.
The suspension was neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 12.3
15 Al as TMA: 1.6
Example 6
Suspension of methylaluminoxane and metallocene in
20 white oil
- 60.5 g of a toluene solution of MA0 (Al
content, 13.2~; Al as TMA, 3.19~) were fed into a
stirring apparatus under a protective argon
25 atmosphere. 2.0 g EURECEN~ 5036 (trade name of the
Witco Company, Bergkamen, Germany - 1,2-ethylenebis(1-
indenyl)zirconium dichloride) were added to this
solution, and stirring was carried out for 30 min. 39
g white oil Witco Parol~ were metered into this dark-
brown solution and heated to 40~C. The toluene was
2~ 1ulu243
l distilled off under a vacuum of up to 0.1 mbar and
condensed in a low-temperature trap.
56.6 g of a brown, waxli~e catalyst mass was
obtained.
The suspension was neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 14.11%
Zr: 0.77%
Example 7
The procedure was carried out as in Example
6. Before use in the polymerization, the mixture was
subjected to a 24-h aging process in toluene.
Example 8
The procedure was carried out as in Example
6. Before use in-the polymerization, the mixture was
subjected to a 48-h aging process in toluene.
Example 9
Suspension of supported MA0/metallocene/silica
catalyst system in Witco Parol~
23 g of a supported catalyst system (TA
02954, research product from the Witco Company; Al
22 i~u2~3
-16-
l content, 23.9~, Zr content 1.1~) were stirred with
53.7 g while oil Witco Parol~ in a stirred vessel
under a protective argon atmosphere. A dark-brown
suspension was obtained.
The suspension was neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 7.17
Zr total: 0.33
Example 10
Metallocene/methylaluminoxane/silica suspension in
white oil
203.5 g of a 10~ solution of
methylaluminoxane in toluene (Al content, 5.0~) were
introduced into an apparatus suitable for working
under a protective argon atmosphere, with stirrer,
thermometer, reflux condenser, and metering of solids.
18.8 g Silica (SYLOPOL 2104~, ~race Company,
with 5% water content) were thoroughly shaken with 1.5
g distilled water for approximately 10 min, poured
into the solids meter, and slowly added to the stirred
methylalllm;noxane solution. With gas development
(methane gas), the temperature rose to 65~C. After
the end of the addition, stirring was carried out
- until room temperature was once again reached, and
then 2.44 g EURECEN~ 5036 1,2-ethylenebis(1-
indenyl)zirconium dichloride) were added. Stirring
2~U243
-17-
l was then carried out for 1.5 h, wherein the flask
contents turned red-brown. Then 121.2 g of white oil
(Witco Parol~) were added, in order to attain an
approximately 25% suspension.
The toluene was completely distilled off at
a maximum of 45~C and a vacuum of up to 0.1 mbar in 6
h. A red-brown, highly viscous suspension was
obtained.
The suspension was neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 5.25%
Zr: 0.27%
Example 11
Metallocene/methylaluminoxane/silica suspension in
white oil
52.4 g of silica (SYLOPOL~ 2104) on which
was supported methylaluminoxane, with an aluminum
content of 23.8~, was fed under a protective nitrogen
atmosphere, and 3.14 g -EURECEN~ 5036 were added.
111.1 g white oil (Witco Parol~) were added to this
mixture of solids and stirred for over 2 h. A
viscous, curry-colored 33~ suspension was obtained.
The suspension was neither pyrophoric nor
self-igniting; slight gas generation took place on
addition of water.
Al total: 7.48%
22~u24~
-18-
l Zr: 0.38~ -
Comparative examples
In Comparative Examples 12 and 13 a
commercial MAO solution, sold by the Witco Company,
Bergkamen, Germany, under the trade name EURECEN~ Al
5100/lOT, was used and together with the other
catalyst components, metered directly into the
polymerization reactor. The concentrations of the
active catalyst material can be seen in Tables I and
II.
Polymerization results
Polymerization results and analytical data for
homogeneous formulations
3o
2 L ~ U 2 43
--19--
Table I *
Example Formulation %Al, ~Zr in Productivity of the
Formulation formulation, kg
PE/mol Zr h
l MAO in Paroll~ 13.4; o.00 30552
2 MA0 in Petroleum 12.0; 0.00 29880
Jelly'~
3 MA0 (solid) in 26.1; 0.00 35256
paraffin
4 MA0 in Paroll~ 30.1 0.00 55584
MAO in Va~eline 12.3; 0.00 25704
(S~ nn~ 1)
6 MAO/ 14.11 0.77 3456
metallocene2~
prepared-in Parol
and polynierized
immediately
7 MA0/ 14.11 0.77 29964
metallocene2l,
prepared in Parol
and polymerized
after 24 h
8 MA0/ 14.11 0.77 57288
metallocene2~,
prepared in Parol
and polymerized
after 48 h
12 MA0 in toluene 4.84; 0.00 29328
(Comparative
Example)l)
1) = Bis(n-butylcyclopentadienyl)zirconium dichloride
2) = Ethylene-1.2-bi~indenyl) zirconium dichloride
(MA0: 900 g/mol; metallocene, ab~. conc. conc. 1.25 x 10-6 mol Zr;
Al:Zr=1000:1); 900 mL toluene; 30~C in~ide temperature; 4 bar
ethene; 1000 rpm; 20 min)
3o
2~0~)24~
-20-
-
1 Polymerization results and analytical data for
heterogeneous formulations
Table II
Example Formulation ~Al ~Zr Productivity
kg PE/mol
Zr h
9 MAO/SiO2/ 7.17 0.33 4200
Metallocene,
suspended in
Parol2 ~ .
MAO/SiO2/ 5.25 0.27 2228
Metallocene,
prepared in
Parol2~ .
11 MAo/sio2/ 7.48 0.38 1081
Metallocene,
prepared in
Parol2)
13 MAO/SiO2/ 5.2S 0.27 688
Metallocene,
suspended in
toluene
(Comparative
Example)2)
1) = Bis(n-butylcycolpentadienyl)zirconium dichloride
2) = Ethylene-1,2-bis(indenyl)zirconium dichloride
(MAo/Sio2, 23.8~ Al; metallocene abs. conc. 1.25 x 10-6
mole Zr; triisobutylaluminum (Al:Zr=800:1); 900 mL
toluene; 40~C inside temperature; 4 bar ethene; 1000
rpm; 20 min)
3o
