Supported catalyst systems

Details Supported catalyst systems Supported catalyst systems

1998-08-17

2002-02-26

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S155000, C526S160000, C502S104000, C502S117000, C502S152000, C502S132000

Reexamination Certificate

active

06350829

ABSTRACT:

The present invention relates to supported catalyst systems obtainable by
A) reaction of an inorganic carrier with a metal compound of the general formula I
M
1
(R
1
)
r
(R
2
)
s
(R
3
)
t
(R
4
)
u
  I
 where
M
1
is an alkali metal, an alkaline earth metal or a metal of main group III or IV of the Periodic Table,
R
1
is hydrogen, C
1
-C
10
-alkyl, C
6
-C
15
-aryl, alkylaryl or arylalkyl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,
R
2
to R
4
are each hydrogen, halogen, C
1
-C
10
-alkyl, C
6
-C
15
-aryl, alkylaryl, arylalkyl, alkoxy or dialkylamino, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,
r is an integer from 1 to 4 and
s, t and u are integers from 0 to 3, the sum r+s+t+u corresponding to the valency of M
1
,
B) reaction of the material obtained according to A) with a metallocene complex in its metal dihalide form and a compound forming metallocenium ions and
C) subsequent reaction with a metal compound of the general formula II
M
2
(R
5
)
0
(R
1
)
p
(R
1
)
q
  II
 where
M
2
is an alkali metal, an alkaline earth metal or a metal of main group III of the Periodic Table,
R
5
is hydrogen, C
1
-C
10
-alkyl, C
6
-C
15
-aryl, alkylaryl or arylalkyl each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,
R
6
and R
7
are each hydrogen, halogen, C
1
-C
10
-alkyl, C
6
-C
15
-aryl, alkylaryl, arylalkyl or alkoxy, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20carbon atoms in the aryl radical,
o is an integer from 1 to 3 and
p and q are integers from 0 to 2, the sum o+p+q corresponding to the valency of M
2
.
The present invention furthermore relates to processes for the preparation of such supported catalyst systems and their use for the preparation of polyolefins.
In recent years, homogeneous metallocene catalysts have made it possible to obtain well defined poly-l-olefins having a narrow molecular weight distribution and high chemical uniformity. However, industrial use necessitates the conversion of these catalysts to heterogeneous form so that simple handling of the catalyst and effective control of the morphology of the product are ensured. Supported metallocene catalysts are known per se. Thus, EP-A 323 716 describes those systems in which moist SiO
2
is reacted with a trialkyl aluminum to give an alumoxane-laden carrier. The metallocene is applied to this carrier, an active catalyst being formed.
WO 91/09882 discloses the preparation of a supported, cationic metallocene catalyst by applying the reaction mixture of the dialkylmetallocene with an ionic compound, which has a Bronsted acid as the cation and a noncoordinating opposite ion, such as tetrakis(pentafluorophenyl)borate, as the anion, to an inorganic carrier. Here too, an active catalyst is obtained.
Similar supported catalyst systems are also disclosed in WO 94/03506 and WO 95/14044.
EP-A 628 574 describes supported catalyst systems in which a metallocene dihalide is reacted with an alkyl aluminum in the presence of a hydridoborate and this solution, which is active with respect to polymerization, is applied to a carrier.
Such catalysts which are already active readily give rise to problems in the metering of the catalyst into the reactor.
What is therefore advantageous is a catalyst which is still inactive and cannot be activated until a later stage, for example during metering or in the reactor itself.
EP-A 613 908 discloses supported metallocene catalyst systems, some of which are not activated until they are in the reactor. Here, however, the polymers formed have a broad molecular weight distribution M
w
/M
n
.
WO 95/15815 describes catalysts which are obtained by supporting a metallocene dichloride and a borate on a crosslinked polymer. The use of deactivated inorganic carriers gives catalysts which, after activation in the polymerization reactor, have either only slight activity or no activity at all.
It is an object of the present invention to provide supported catalyst systems which do not have the stated disadvantages, in particular can be activated at any desired time, are air- and moisture-insensitive, can be stored for a long time and are not flammable, the polymers formed having a narrow molecular weight distribution.
We have found that this object is achieved by the supported catalyst systems defined at the outset.
We have furthermore found processes for the preparation of such supported catalyst systems and their use for the preparation of polyolefins.
The novel supported catalyst systems are obtainable by reacting an inorganic carrier with a metal compound of the general formula I in a first stage A).
Preferably used carriers are finely divided solids whose particle diameters are from 1 to 200 &mgr;m, in particular from 30 to 70 &mgr;m.
Examples of suitable carriers are silica gels, preferably those of the formula SiO
2
a Al
2
O
3
, where a is from 0 to 2, preferably from 0 to 0.5; these are therefore aluminosilicates or silica.
Such products are commercially available, for example Silica Gel 332 from Grace.
Other inorganic compounds, such as Al
2
O
3
or MgCl
2
, or mixtures containing these compounds may also be used as carriers.
Preferred metal compounds of the general formula I are those in which M
1
is a metal of main group III of the Periodic Table, in particular aluminum, R
1
is C
1
-C
10
-alkyl and R
2
to R
4
are each C
1
-C
10
-alkyl. For the particularly preferred case where M
1
is aluminum, u is zero and R
1
to R
3
have in particular the same meaning, preferably methyl, ethyl, isobutyl or hexyl, preferably isobutyl.
Preferably, the metal compound of the general formula I is added as a solution to a suspension of the carrier. Particularly suitable solvents or suspending agents are hydrocarbons, such as heptane. The amount of metal compound I may be varied within wide limits, the minimum amount depending on the number of hydroxyl groups of the carrier. The temperatures, reaction times and pressures are not critical per se, temperatures of from 0 to 80° C. and reaction times of from 0.1 to 48 hours being preferred.
It has proven suitable to remove the excess metal compound I by thorough washing, for example with hydrocarbons, such as pentane or hexane, after the carrier pretreatment and to dry the carrier.
The material thus prepared can be stored for up to 6 months and is not pyrophoric.
This material is then reacted, in a further stage B), with a metallocene complex in its metal dihalide form and a compound forming metallocenium ions.
Examples of suitable metallocene complexes are the following compounds of the general formula III:
where
M is titanium, zirconium, hafnium, vanadium, niobium or tantalum,
x is fluorine, chlorine, bromine or iodine,
R
8
to R
12
are each hydrogen, C
1
-C
10
-alkyl, 5- to 7-membered cycloalkyl which in turn may carry a C
1
-C
10
-alkyl as a substituent, C
6
-C
15
-aryl or arylalkyl, where two adjacent radicals together may furthermore form a cyclic group of 4 to 15 carbon atoms, or Si(R
13
)
3
, where
R
13
is C
1
-C
10
-alkyl, C
3
-C
10
-cycloalkyl or C
6
-C
15
-aryl, and
z is X or
where
R
14
to R
18
are each hydrogen, C
1
-C
10
-alkyl, 5- to 7-membered cycloalkyl which in turn may carry a C
1
-C
10
-alkyl as a substituent, C
6
-C
15
-aryl or arylalkyl, where two adjacent radicals together may furthermore form a cyclic group of 4 to 15 carbon atoms, or Si(R
19
)
3
, where
R
19
is C
1
-C
10
-alkyl, C
6
-C
15
-aryl or C
3
-C
10
-cycloalkyl,
or where R
11
and Z together form a group —R
20
—A—, where
 ═BR
22
, ═AlR
22
, —Ge—, —Sn—, —O—, —S—, ═SO, ═SO
2
, ═NR
22
, ═CO, ═PR
22
or ═P(O)R
22
,
where R
21
, R
22
and R
23
are identical or different and are each hydrogen, halogen, C
1
-C
10
-alkyl, C
1
-C
10
-fluoroalkyl, C
6
-C
10
-fluoroaryl, C
6
-C
10
-aryl, C
1
-C
10
-alkoxy, C
2
-C
10
-alkenyl, C
7
-C
40
-arylalkyl, C
8
-C
40
-arylalkenyl or C
7
-C
40
-alkylaryl or where two a

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