Supported catalyst system, process for its production and its use in polymerizing olefins

A catalyst system comprises at least one metallocene and at least one passivated support and preferably at least one cocatalyst. The passivated support is prepared by treating at least one inorganic oxide with at least one organometallic compound, preferably in an inorganic solvent. A polymer having a melting point of .gtoreq.158.degree. C., a proportion of reverse insertions of <0.2% and a triad tacticity of >98.0% can be obtained using this catalyst system.

The present invention relates to a highly active, supported catalyst system
 which can advantageously be used in olefin polymerization and to a process
 for its preparation, and also to polymers which are prepared using the
 supported catalyst system.
 Processes for preparing polyolefins with the aid of soluble, homogeneous
 catalyst systems comprising a transition metal component of the
 metallocene type and a cocatalyst component of the aluminoxane, Lewis acid
 or ionic type are known. These catalysts give polymers and copolymers
 having a narrow molar mass distribution with high activity.
 In polymerization processes using soluble, homogeneous catalyst systems,
 heavy deposits form on reactor walls and stirrer if the polymer is
 obtained as a solid. These deposits are always formed by agglomeration of
 the polymer particles if metallocene and/or cocatalyst are present in
 dissolved form in the suspension. Such deposits in the reactor systems
 have to be removed regularly, since they quickly reach considerable
 thicknesses, have a high strength and prevent heat transfer to the cooling
 medium. Furthermore, homogeneous catalyst systems cannot be used for
 preparing polyolefins in the gas phase.
 To avoid deposit formation in the reactor, the use of supported catalyst
 systems in which the metallocene and/or the aluminum compound serving as
 cocatalyst are fixed on an inorganic support material have been proposed.
 EP 576 970 A1 discloses a catalyst system comprising a metallocene of the
 formula
 ##STR1##
 where
 M.sup.a is a metal of group IVb, Vb or VIb of the Periodic Table,
 R.sup.a and R.sup.b are identical or different and are each a hydrogen
 atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -alkoxy group,
 a C.sub.6 -C.sub.10 -aryl group, a C.sub.6 -C.sub.10 -aryloxy group, a
 C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a
 C.sub.7 -C.sub.40 -alkylaryl group, a C.sub.8 -C.sub.40 -arylalkenyl
 group, an OH group or a halogen atom,
 the radicals R.sub.c are identical or different and are each a hydrogen
 atom, a halogen atom, a C.sub.1 -C.sub.10 -alkyl group which may be
 halogenated, a C.sub.6 -C.sub.10 -aryl group, an --NR.sup.P.sub.2,
 --SR.sup.P, --OSiR.sup.P.sub.3 -- or --PR.sup.P.sub.2 radical, where
 R.sup.P is a halogen atom, a C.sub.1 -C.sub.10 -alkyl group or a C.sub.6
 -C.sub.10 -aryl group,
 R.sup.d to R.sup.1 are identical or different and are as defined for
 R.sup.c, or adjacent radicals R.sup.d to R.sup.1 together with the atoms
 connecting them form one or more aromatic or aliphatic rings, or the
 radicals R.sup.e and R.sup.h or R.sup.1 together with the atoms connecting
 them form an aromatic or aliphatic ring,
 R.sup.m is
 ##STR2##
 where R.sup.n and R.sup.o are identical or different and are each a
 hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1
 -C.sub.10 -fluoroalkyl group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.6
 -C.sub.10 -aryl group, a C.sub.6 -C.sub.10 -fluoroaryl group, a C.sub.6
 -C.sub.10 -aryloxy group, a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7
 -C.sub.40 -arylalkyl group, a C.sub.7 -C.sub.40 -alkylaryl group or a
 C.sub.8 -C.sub.40 -arylalkenyl group, or R.sup.n and R.sup.o, in each case
 together with the atoms connecting them, form one or more rings and
 M.sup.b is silicon, germanium or tin,
 and a supported cocatalyst.
 An isotactic polypropylene having a melting point below 157.degree. C. is
 obtained using this catalyst system.
 EP 287 666 B1 discloses a process for the polymerization of olefins in the
 presence of a catalyst comprising a compound of a transition metal, an
 inorganic support, an aluminoxane and an organoaluminum compound having a
 hydrocarbon group different from n-alkyl groups as solid catalyst
 component, wherein the transition metal compound has the formula
EQU R.sup.q.sub.k R.sup.r.sub.l R.sup.s.sub.m R.sup.t.sub.n Me,
 where R.sup.q is a cycloalkadienyl group, R.sup.r, R.sup.s and R.sup.t are
 identical or different and are each a cycloalkadienyl group, an aryl
 group, an alkyl group, an arylalkyl group, a halogen atom or a hydrogen
 atom, Me is zirconium, titanium or hafnium, k is 1, 2, 3 or 4, 1, m and n
 are 0, 1, 2 or 3 and k+l+m+n=4.
 This process gives polymers in good yields.
 EP 336 593 B1 discloses a process for preparing a metallocene/aluminoxane
 catalyst provided with a support for olefin polymerization, in which
 trialkylaluminum and water are reacted in the presence of a
 water-absorbing solid material at a molar ratio of trialkylaluminum to
 water of from 10:1 to 1:1 and a metallocene of a transition metal is added
 to the reacted mixture, with the water being absorbed by the solid
 material in an amount of from 10 to 50% by weight prior to the reaction,
 the water-containing solid material being added to a solution of
 trialkylaluminum and the molar ratio of aluminum to metallocene transition
 metal being from 1000:1 to 1:1.
 By this process, the cocatalyst is immobilized on the support. An
 advantageous molar ratio of aluminum to metallocene transition metal is
 obtained.
 DE 4330667 A1 discloses a process for preparing catalyst systems using a
 pretreated support. In this process, the support material is reacted with
 a solution of triethylaluminum in heptane. Preference is given to using
 catalyst systems comprising a mixture of a plurality of metallocene
 complexes and/or a Ziegler-Natta catalyst system in the polymerization.
 When using metallocene complexes and Ziegler-Natta catalysts,
 polypropylenes having a melting point of &gt;160.degree. C. are obtained.
 Polypropylenes having melting points of &lt;150.degree. C. are prepared when
 only metallocenes are used as catalysts.
 It is an object of the present invention to provide a highly active,
 supported catalyst system which gives polymers having a high
 regioregularity and stereoregularity and also an environmentally friendly
 and economical process for preparing the polymers.
 We have found that this object is achieved by a catalyst system comprising
 at least one metallocene and at least one passivated support.
 According to the present invention, the catalyst system is prepared by
 mixing at least one metallocene and at least one passivated support.
 The metallocene component of the catalyst system of the present invention
 can be essentially any metallocene. The metallocene can be either bridged
 or unbridged and have identical or different ligands. Preference is given
 to metallocenes of group IVb of the Periodic Table of the Elements, viz.
 titanium, zirconium or hafnium, preferably zirconium.
 The metallocenes preferably have the formula I
 ##STR3##
 where
 M.sup.1 is a metal of group IVb of the Periodic Table of the Elements,
 R.sup.1 and R.sup.2 are identical or different and are each a hydrogen
 atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -alkoxy group,
 a C.sub.6 -C.sub.20 -aryl group, a C.sub.6 -C.sub.20 -aryloxy group, a
 C.sub.2 -C.sub.10 -alkenyl group, an OH group, an NR.sup.12.sub.2 group,
 where R.sup.12 is a C.sub.1 -C.sub.2 -alkyl group or a C.sub.6 -C.sub.14
 -aryl group, or a halogen atom,
 R.sup.3 to R.sup.8 and R.sup.3 ' to R.sup.8 ' are identical or different
 and are each a hydrogen atom, a C.sub.1 -C.sub.40 -hydrocarbon group which
 may be linear, cyclic or branched, e.g. a C.sub.1 -C.sub.10 -alkyl group,
 a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.6 -C.sub.20 -aryl group, a
 C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.7 -C.sub.40 -alkylaryl group
 or a C.sub.8 -C.sub.40 -arylalkenyl group, or adjacent radicals R.sup.4 to
 R.sup.8 and/or R.sup.4 ' to R.sup.8 ' together with the atoms connecting
 them form a ring system,
 R.sup.9 is a bridge, preferably
 ##STR4##
 where R.sup.10 and R.sup.11 are identical or different and are each a
 hydrogen atom, a halogen atom or a C.sub.1 -C.sub.40 -group such as a
 C.sub.1 -C.sub.20 -alkyl group, a C.sub.1 -C.sub.10 -fluoroalkyl group, a
 C.sub.1 -C.sub.10 -alkoxy group, a C.sub.6 -C.sub.14 -aryl group, a
 C.sub.6 -C.sub.10 -fluoroaryl group, a C.sub.6 -C.sub.10 -aryloxy group, a
 C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a
 C.sub.7 -C.sub.40 -alkylaryl group or a C.sub.8 -C.sub.40 -arylalkenyl
 group, or R.sup.10 and R.sup.11, in each case together with the atoms
 connecting them, form one or more rings and x is an integer from zero to
 18, M.sup.2 is silicon, germanium or tin, and the rings A and B are
 identical or different, saturated or unsaturated. R.sup.9 can also link
 two units of the formula I to one another.
 The 4,5,6,7-tetrahydroindenyl analogs corresponding to the compounds I are
 likewise of importance.
 In formula I, it is preferred that
 M.sup.1 is zirconium,
 R.sup.1 and R.sup.2 are identical and are methyl or chlorine, in particular
 chlorine, and R.sup.9 =M.sup.2 R.sup.10 R.sup.11, where M.sup.2 is silicon
 or germanium and R.sup.10 and R.sup.11 are each a C.sub.1 -C.sub.20
 -hydrocarbon group such as C.sub.1 -C.sub.10 -alkyl or C.sub.6 -C.sub.14
 -aryl,
 R.sup.5 and R.sup.5 ' are preferably identical or different and are each a
 C.sub.6 -C.sub.10 -aryl group, a C.sub.7 -C.sub.10 -arylalkyl group, a
 C.sub.7 -C.sub.40 -alkylaryl group or a C.sub.8 -C.sub.40 -arylalkenyl
 group.
 The indenyl or tetrahydroindenyl ligands of the metallocenes of the formula
 I are preferably substituted in the 2 position, 2,4 positions, 4,7
 positions, 2,6 positions, 2,4,6 positions, 2,5,6 positions, 2,4,5,6
 positions or 2,4,5,6,7 positions, in particular in the 2,4 positions.
 Preferred substituents are a C.sub.1 -C.sub.4 -alkyl group such as methyl,
 ethyl or isopropyl or a C.sub.6 -C.sub.10 -aryl group such as phenyl,
 naphthyl or mesityl. The 2 position is preferably substituted by a C.sub.1
 -C.sub.4 -alkyl group such as methyl or ethyl.
 Particular preference is given to zirconocenes which bear tetrahydroindenyl
 derivatives and indenyl derivatives as ligands.
 Furthermore, particularly important metallocenes of the formula I are those
 in which the substituents in the 4 and 5 positions of the indenyl radicals
 (R.sup.5 and R.sup.6 or R.sup.5 ' and R.sup.6 ') together with the atoms
 connecting them form a ring system, preferably a 6-membered ring. This
 condensed ring system can likewise be substituted by radicals defined as
 for R.sup.3 -R.sup.8. An example of such a compound I is
 dimethylsilanediylbis(2-methyl-4,5-benzindenyl)zirconium dichloride.
 Very particular preference is given to those compounds of the formula I
 which bear a C.sub.6 -C.sub.20 -aryl group in the 4 position and a C.sub.1
 -C.sub.4 -alkyl group in the 2 position. An example of such a compound of
 the formula I is dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium
 dichloride.
 Examples of metallocene components of the catalyst system of the present
 invention are:
 dimethylsilanediylbis(indenyl)zirconium dichloride
 dimethylsilanediylbis(4-naphthylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methylbenzindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-(1-naphthyl)indenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-(2-naphthyl)indenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-t-butylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-isopropylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-ethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-.alpha.-acenaphthindenyl)zirconium
 dichloride
 dimethylsilanediylbis(2,4-dimethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-ethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-ethyl-4-ethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-ethyl-4-phenylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4,5-benzindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4,5-diisopropylindenyl)zirconium dichloride
 dimethylsilanediylbis(2,4,6-trimethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2,5,6-trimethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2,4,7-trimethylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-5-isobutylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-5-t-butylindenyl)zirconium dichloride
 methyl(phenyl)silanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride
 methyl(phenyl)silanediylbis(2-methyl-4,6-diisopropylindenyl)-zirconium
 dichloride
 methyl(phenyl)silanediylbis(2-methyl-4-isopropylindenyl)zirconium
 dichloride
 methyl(phenyl)silanediylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride
 methyl(phenyl)silanediylbis(2-methyl-4,5-(methylbenzo)indenyl)-zirconium
 dichloride
 methyl(phenyl)silanediylbis(2-methyl-4,5-(tetramethylbenzo)-indenyl)zirconi
 um dichloride
 methyl(phenyl)silanediylbis(2-methyl-4-.alpha.-acenaphthindenyl)-zirconium
 dichloride
 methyl(phenyl)silanediylbis(2-methylindenyl)zirconium dichloride
 methyl(phenyl)silanediylbis(2-methyl-5-isobutylindenyl)zirconium dichloride
 1,2-ethanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride
 1,4-butanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride
 1,2-ethanediylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride
 1,4-butanediylbis(2-methyl-4-isopropylindenyl)zirconium dichloride
 1,4-butanediylbis(2-methyl-4,5-benzindenyl)zirconium dichloride
 1,2-ethanediylbis(2-methyl-4,5-benzindenyl)zirconium dichloride
 1,2-ethanediylbis(2,4,7-trimethylindenyl)zirconium dichloride
 1,2-ethanediylbis(2-methylindenyl)zirconium dichloride
 1,4-butanediylbis(2-methylindenyl)zirconium dichloride
 bis (butylcyclopentadienyl) Zr.sup.+ CH.sub.2 CHCHCH.sub.2 B.sup.- (C.sub.6
 F.sub.5).sub.3
 bis(methylindenyl)Zr.sup.+ CH.sub.2 CHCHCH.sub.2 B.sup.- (C.sub.6
 F.sub.5).sub.3
 dimethylsilanediylbis (2-methyl-4,5-benzindenyl) Zr.sup.+ CH.sub.2
 CHCHCH.sub.2 B.sup.- (C.sub.6 F.sub.5).sub.3
 1,2-ethanediylbis(2-methylindenyl)Zr.sup.+ CH.sub.2 CHCHCH.sub.2 B.sup.-
 (C.sub.6 F.sub.5).sub.3
 1,4-butanediylbis(2-methylindenyl)Zr.sup.+ CH.sub.2 CHCHCH.sub.2 B.sup.-
 (C.sub.6 F.sub.5).sub.3
 dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)-Zr.sup.+ CH.sub.2
 CHCHCH.sub.2 B.sup.- (C.sub.6 F.sub.5).sub.3
 dimethylsilanediylbis(2-ethyl-4-phenylindenyl)Zr.sup.+ CH.sub.2
 CHCHCH.sub.2 B.sup.- (C.sub.6 F.sub.5).sub.3
 dimethylsilanediylbis(2-methyl-4-phenylindenyl)Zr.sup.+ CH.sub.2
 CHCHCH.sub.2 B.sup.- (C.sub.6 F.sub.5).sub.3
 methyl(phenyl)silanediylbis(2-methyl-4-phenylindenyl)-Zr.sup.+ CH.sub.2
 CHCHCH.sub.2 B.sup.- (C.sub.6 F.sub.5).sub.3
 dimethylsilanediylbis (2-methylindenyl) Zr.sup.+ CH.sub.2 CHCHCH.sub.2
 B.sup.- (C.sub.6 F.sub.5).sub.3
 dimethylsilanediylbis(indenyl)Zr.sup.+ CH.sub.2 CHCHCH.sub.2 B.sup.-
 (C.sub.6 F.sub.5).sub.3
 dimethylsilanediyl(tert-butylamido)(tetramethylcyclopentadienyl)-zirconium
 dichloride
 [tris(pentafluorophenyl)(cyclopentadienylidene)borato](cyclo-pentadienyl)-1
 ,2,3,4-tetraphenylbuta-1,3-dienylzirconium
 dimethylsilanediyl[tris(pentafluorophenyl)(2-methyl-4-phenyl-indenylidene)b
 orato](2-methyl-4-phenylindenyl)-1,2,3,4-tetra-phenylbuta-1,3-dienylzirconi
 um
 dimethylsilanediyl[tris(trifluoromethyl)(2-methylbenzindenyl-idene)borato](
 2-methylbenzindenyl)-1,2,3,4-tetraphenylbuta-1,3-dienylzirconium
 dimethylsilanediyl[tris(pentafluorophenyl)(2-methylindenylidene)-borato](2-
 methylindenyl)-1,2,3,4-tetraphenylbuta-1,3-dienyl-zirconium
 dimethylsilanediylbis(indenyl)dimethylzirconium
 dimethylsilanediylbis(4-naphthylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methylbenzoindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-4-(2-naphthyl)indenyl)dimethyl-zirconium
 dimethylsilanediylbis(2-methyl-4-(2-naphthyl)indenyl)dimethyl-zirconium
 dimethylsilanediylbis(2-methyl-4-phenylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-4-t-butylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-4-isopropylindenyl)dimethyl-zirconium
 dimethylsilanediylbis(2-methyl-4-ethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-4-.alpha.-acenaphthindenyl)dimethyl-zirconiu
 m
 dimethylsilanediylbis(2,4-dimethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-ethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-ethyl-4-ethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-ethyl-4-phenylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-4,5-benzindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)dimethyl-zirconium
 dimethylsilanediylbis(2-methyl-4,5-diisopropylindenyl)dimethyl-zirconium
 dimethylsilanediylbis(2,4,6-trimethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2,5,6-trimethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2,4,7-trimethylindenyl)dimethylzirconium
 dimethylsilanediylbis(2-methyl-5-isobutylindenyl)dimethyl-zirconium
 dimethylsilanediylbis(2-methyl-5-t-butylindenyl)dimethylzirconium
 methyl(phenyl)silanediylbis(2-methyl-4-phenylindenyl)dimethyl-zirconium
 methyl(phenyl)silanediylbis(2-methyl-4,6-diisopropylindenyl)-dimethylzircon
 ium
 methyl(phenyl)silanediylbis(2-methyl-4-isopropylindenyl)dimethyl-zirconium
 methyl(phenyl)silanediylbis(2-methyl-4,5-benzindenyl)dimethyl-zirconium
 methyl(phenyl)silanediylbis(2-methyl-4,5-(methylbenzo)indenyl)-dimethylzirc
 onium
 methyl(phenyl)silanediylbis(2-methyl-4,5-(tetramethylbenzo)-indenyl)dimethy
 lzirconium
 methyl(phenyl)silanediylbis(2-methyl-4-.alpha.-acenaphthindenyl)-dimethylzi
 rconium
 methyl(phenyl)silanediylbis(2-methylindenyl)dimethylzirconium
 methyl(phenyl)silanediylbis(2-methyl-5-isobutylindenyl)dimethyl-zirconium
 1,2-ethanediylbis(2-methyl-4-phenylindenyl)dimethylzirconium
 1,4-butanediylbis(2-methyl-4-phenylindenyl)dimethylzirconium
 1,2-ethanediylbis(2-methyl-4,6-diisopropylinidenyl)dimethyl-zirconium
 1,4-butanediylbis(2-methyl-4-isopropylindenyl)dimethylzirconium
 1,4-butanediylbis(2-methyl-4,5-benzindenyl)dimethylzirconium
 1,2-ethanediylbis(2-methyl-4,5-benzindenyl)dimethylzirconium
 1,2-ethanediylbis(2,4,7-trimethylindenyl)dimethylzirconium
 1,2-ethanediylbis(2-methylindenyl)dimethylzirconium
 1,4-butanediylbis(2-methylindenyl)dimethylzirconium
 Particular preference is given to:
 dimethylsilanediylbis(2-methylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-(1-naphthyl)indenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4-.alpha.-acenaphthindenyl)zirconium
 dichloride
 dimethylsilanediylbis(2-ethyl-4-phenylindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4,5-benzindenyl)zirconium dichloride
 dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride.
 Methods of preparing metallocenes of the formula I are described, for
 example, in Journal of Organometallic Chem. 288 (1985) 63-67 and the
 documents cited therein.
 The catalyst system of the present invention preferably further comprises
 at least one cocatalyst.
 The cocatalyst component which, according to the present invention, may be
 present in the catalyst system comprises at least one compound of the
 aluminoxane, Lewis acid or ionic type which reacts with a metallocene to
 convert the latter into a cationic compound.
 As aluminoxane, preference is given to using a compound of the formula II
EQU (R AlO).sub.n (II).
 Aluminoxanes can be, for example, cyclic as in formula III
 ##STR5##
 or of the cluster type as in formula V, as is described in recent
 literature; cf. JACS 117 (1995), 6465-74, Organometallics 13 (1994),
 2957-2969.
 ##STR6##
 The radicals R in the formulae (II), (III), (IV) and (V) can be identical
 or different and can each be a C.sub.1 -C.sub.20 -hydrocarbon group such
 as a C.sub.1 -C.sub.6 -alkyl group, a C.sub.6 -C.sub.18 -aryl group,
 benzyl or hydrogen, and p can be an integer from 2 to 50, preferably from
 10 to 35.
 Preferably, the radicals R are identical and are methyl, isobutyl, n-butyl,
 phenyl or benzyl, particularly preferably methyl.
 If the radicals R are different, they are preferably methyl and hydrogen,
 methyl and isobutyl or methyl and n-butyl, with hydrogen and isobutyl or
 n-butyl preferably being present in an amount of 0.01-40% (number of
 radicals R).
 The aluminoxane can be prepared in various ways by known methods. One of
 the methods is, for example, reacting an aluminum-hydrocarbon compound
 and/or a hydridoaluminum-hydrocarbon compound with water (gaseous, solid,
 liquid or bound, for example as water of crystallization) in an inert
 solvent (such as toluene). To prepare an aluminoxane having different
 alkyl groups R, two different trialkylaluminums (AlR.sub.3 +AlR'.sub.3)
 corresponding to the desired composition and reactivity are reacted with
 water (cf. S. Pasynkiewicz, Polyhedron 9 (1990) 429 and EP-A 302 424).
 Regardless of the method of preparation, all aluminoxane solutions have in
 common a varying content of unreacted aluminum starting compound which is
 present in free form or as adduct.
 As Lewis acid, preference is given to using at least one organoboron or
 organoaluminum compound comprising C.sub.1 -C.sub.20 - groups such as
 branched or unbranched alkyl or haloalkyl, e.g. methyl, propyl, isopropyl,
 isobutyl or trifluoromethyl, or unsaturated groups such as aryl or
 haloaryl, e.g. phenyl, tolyl, benzyl groups, p-fluorophenyl,
 3,5-difluorophenyl, pentachlorophenyl, penta- fluorophenyl,
 3,4,5-trifluorophenyl and 3,5-di(trifluoromethyl)-phenyl.
 Particular preference is given to organoboron compounds. Examples of Lewis
 acids are trifluoroborane, triphenylborane, tris-(4-fluorophenyl)borane,
 tris(3,5-difluorophenyl)borane, tris(4-fluoromethylphenyl)borane,
 tris(pentafluorophenyl)borane, tris(tolyl)borane,
 tris(3,5-dimethylphenyl)borane, tris(3,5-difluorophenyl)borane and/or
 tris(3,4,5-trifluorophenyl)borane. Very particular preference is given to
 tris(pentafluorophenyl)-borane.
 As ionic cocatalysts, preference is given to using compounds which contain
 a noncoordinating anion such as tetrakis(penta-fluorophenyl)borates,
 tetraphenylborates, SbF.sub.6.sup..crclbar., CF.sub.3
 SO.sub.3.sup..crclbar. or ClO.sub.4.sup..crclbar.. As cationic counterion,
 use is made of Lewis bases such as metyhlamine [sic], aniline,
 dimethylamine, diethylamine, N-methylaniline, diphenylamine,
 N,N-dimethylaniline, trimethylamine, triethylamine, tri-n-butylamine,
 methyldiphenylamine, pyridine, p-bromo-N,N-dimethylaniline,
 p-nitro-N,N-dimethylaniline, triethylphosphine, triphenylphosphine,
 diphenylphosphine, tetrahydrothiophene and triphenylcarbenium.
 Examples of such ionic compounds according to the present invention are
 triethylammonium tetra(phenyl)borate,
 tributylammonium tetra(phenyl)borate,
 trimethylammonium tetra(tolyl)borate,
 tributylammonium tetra(tolyl)borate,
 tributylammonium tetra(pentafluorophenyl)borate,
 tributylammonium tetra(pentafluorophenyl)aluminate,
 tripropylammonium tetra(dimethylphenyl)borate,
 tributylammonium tetra(trifluoromethylphenyl)borate,
 tributylammonium tetra(4-fluorophenyl)borate,
 N,N-dimethylanilinium tetra(phenyl)borate,
 N,N-diethylanilinium tetra(phenyl)borate,
 N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,
 N,N-dimethylanilinium tetrakis(pentafluorophenyl)aluminate,
 di(propyl)ammonium tetrakis(pentafluorophenyl)borate,
 di(cyclohexyl)ammonium tetrakis(pentafluorophenyl)borate,
 triphenylphosphonium tetrakis(phenyl)borate,
 triethylphosphonium tetrakis(phenyl)borate,
 diphenylphosphonium tetrakis(phenyl)borate,
 tri(methylphenyl)phosphonium tetrakis(phenyl)borate,
 tri(dimethylphenyl)phosphonium tetrakis(phenyl)borate,
 triphenylcarbenium tetrakis(pentafluorophenyl)borate,
 triphenylcarbenium tetrakis(pentafluorophenyl)aluminate,
 triphenylcarbenium tetrakis(phenyl)aluminate,
 ferrocenium tetrakis(pentafluorophenyl)borate and/or
 ferrocenium tetrakis(pentafluorophenyl)aluminate.
 Preference is given to triphenylcarbenium
 tetrakis(penta-fluorophenyl)borate and/or N,N-dimethylanilinium
 tetrakis-(pentafluorophenyl)borate.
 It is also possible to use mixtures of at least one Lewis acid and at least
 one ionic compound.
 Cocatalyst components which are likewise of importance are borane or
 carborane compounds such as 7,8-dicarbaundecaborane(13),
 undecahydrido-7,8-dimethyl-7,8-dicarbaundecaborane,
 dodecahydrido-1-phenyl-1,3-dicarbanonaborane,
 tri(butyl)ammonium undecahydrido-8-ethyl-7,9-dicarbaundecaborate,
 4-carbanonaborane(14)bis(tri(butyl)ammonium) nonaborate,
 bis(tri(butyl)ammonium) undecaborate,
 bis(tri(butyl)ammonium) dodecaborate,
 bis(tri(butyl)ammonium) decachlorodecaborate,
 tri(butyl)ammonium 1-carbadecaborates,
 tri(butyl)ammonium 1-carbadodecaborates,
 tri(butyl)ammonium 1-trimethylsilyl-1-carbadecaborates,
 tri(butyl)ammonium bis(nonahydrido-1,3-dicarbanonaborato)-cobaltates(III),
 tri(butyl)ammonium bis(undecahydrido-7,8-dicarbaundecaborato)-ferrate(III).
 The support components of the catalyst system of the present invention is a
 passivated support, preferably at least one inorganic oxide such as
 silicon oxide, aluminum oxide, zeolites, MgO, ZrO.sub.2, TiO.sub.2,
 B.sub.2 O.sub.3, CaO, ZnO, ThO.sub.2, Na.sub.2 CO.sub.3, K.sub.2 CO.sub.3,
 CaCO.sub.3, MgCO.sub.3, Na.sub.2 SO.sub.4, Al.sub.2 (SO.sub.4).sub.3,
 BaSO.sub.4, KNO.sub.3, Mg(NO.sub.3).sub.2, Al(NO.sub.3).sub.3, Na.sub.2 O,
 K.sub.2 O, Li.sub.2 O in particular silicon oxide and/or aluminum oxide.
 The support thus has a specific surface area in the range from 10 to 1000
 m.sup.2 /g, preferably from 150 to 500 m.sup.2 /g, particularly preferably
 from 200 to 400 m.sup.2 /g. The mean particle size of the support is from
 1 to 500 .mu.m, preferably from 5 to 350 .mu.m, particularly preferably
 from 10 to 200 .mu.m. The pore volume of the support is from 0.5 to 4.0
 ml/g, preferably from 1.0 to 3.5 ml/g, very particularly preferably from
 1.2 to 3 ml/g. This support component is passivated using at least one
 organometallic, preferably organoaluminum, compound. The porous structure
 of the support results in a proportion of voids (pore volume) in the
 support particle, the support material or the shaped support body.
 The shape of the pores is irregular, frequently spherical. Some of the
 pores are connected to one another by means of small pore openings. The
 pore diameter is from about 2 to 50 nm.
 The particle shape of the porous support is dependent on the aftertreatment
 and can be irregular or spherical. The support particle sizes can be set
 to any desired value by, for example, cryogenic milling and/or sieving.
 The passivated support of the present invention comprises a product derived
 from one or more inorganic oxides, preferably silicon oxide and/or
 aluminum oxide, and an organometallic, preferably organoaluminum,
 compound.
 The present invention also provides for the support material to be heated
 to &lt;800.degree. C. or for its surface to be silanized or esterified. The
 support of the present invention is dried at from 100.degree. C. to
 800.degree. C. at from 0.01 bar to 0.001 bar or at from 100.degree. C. to
 800.degree. C. in an inert gas stream for 5-15 hours in order to remove
 physisorbed water. The dried support material contains &lt;1.5% by weight of
 water and from 0.1 to 6% by weight of silanol groups. The water content is
 determined by the weight loss after drying at 200.degree. C. for 4 hours.
 The proportion of silanol groups on the surface can be determined by DTA
 (differential thermal analysis) or according to the following formula: %
 by weight=[(SiO.sub.2 dried at 200.degree. C., 4 h)-(SiO.sub.2 dried at
 1000.degree. C., 20 h)]/(SiO.sub.2 dried at 200.degree. C., 4
 h).multidot.100.
 The support material dried in this way is reacted with at least one
 organometallic compound. The organometallic compound is preferably an
 organoaluminum compound. Particular preference is given to organoaluminum
 compounds containing linear, cyclic or branched, saturated or unsaturated
 C.sub.1 -C.sub.9 carbon-containing groups, e.g. trimethylaluminum,
 triethylaluminum, triisobutylaluminum, methylaluminoxane,
 tripropylaluminum, tri-n-butylaluminum, tri-sec-butylaluminum,
 isobutylaluminoxane, trihexylaluminum, tridodecylaluminum,
 triphenylaluminum, butylaluminoxane, tri(cyclohexyl)aluminum,
 dimethylaluminum methoxide, diethylaluminum ethoxide, diisobutylaluminum
 methoxide, diethylaluminum trimethylsilyloxide, lithium
 butyldiisobutylaluminum, lithium tri-tert-butoxyaluminum, lithium
 tert-butyldiisobutylaluminum and/or diisobutylaluminum
 trimethylsilyloxide. Also suitable are organomagnesium or organoboron
 compounds such as diethylmagnesium, diisopropylmagnesium,
 dipropylmagnesium, dibutylmagnesium,dioctylmagnesium, dihexylmagnesium,
 didodecylmagnesium, dicyclohexylmagnesium, dibenzylmagnesium,
 ditolylmagnesium, dixylylmagnesium, ethylmagnesium ethoxide,
 octylmagnesium ethoxide, octylmagnesium octoxide, ethylpropylmagnesium,
 ethylbutylmagnesium, amylhexylmagnesium, n-butyl-sec-butylmagnesium,
 butyloctylmagnesium, triethylborane, triisobutylborane, tripropylborane,
 tri-n-butylborane, tri-sec-butylborane, trihexylborane, triphenylborane,
 tri(cyclohexyl)borane, dimethylmethoxyborane, diisobutylmethoxyborane,
 diethyltrimethylsilyloxyborane, lithium butyldiisobutylborane, lithium
 tri-tert-butoxyborane, lithium tert-butyldiisobutylborane,
 2-biphenylboronic acid, tris(trimethylsilylmethyl)borane and/or
 phenylboronic acid.
 Very particular preference is given to using trimethylaluminum,
 tributylaluminum, triethylborane and/or tributylborane, but not
 triethylaluminum.
 The passivation of the support is carried out by suspending the support
 material in a suitable solvent such as pentane, hexane, heptane, toluene
 or dichloromethane and slowly adding a solution of the organoaluminum
 compound, e.g. an aluminum alkyl solution, dropwise to this suspension and
 stirring to react the components, or slowly adding a solution of the
 organoaluminum compound, e.g. an aluminum alkyl solution, dropwise to the
 dry support material while stirring and only then preparing a suspension
 using a suitable solvent.
 The reaction temperature is preferably from -20 to +150.degree. C., in
 particular 15-40.degree. C. The reaction time is from 1 to 120 minutes,
 preferably 10-30 minutes. An aluminum concentration of greater than 0.01
 mol/liter, in particular greater than 0.5 mol/liter, is preferably
 employed. Preference is given to using from 0.01 to 0.1 mol of aluminum
 compound per g of support material. The reaction is carried out under
 inert conditions.
 The support is then separated from the solvent. The residue is washed twice
 with a suitable solvent such as pentane, hexane, heptane, toluene or
 dichloromethane and, if desired, dried in an oil pump vacuum at from 20 to
 40.degree. C. and 0.01 to 0.001 bar. This gives a passivated support
 according to the present invention whose proportion of hydroxyl groups on
 the support surface has been reduced by the above-described treatment. The
 proportion of silanol groups on a passivated silica surface has dropped,
 for example, to &lt;2% by weight, preferably &lt;1.5% by weight.
 For the purposes of the present invention, the expression "passivated
 support" means a support which has been treated as described above.
 To prepare the catalyst system of the present invention, the passivated
 support component is reacted with at least one metallocene component and
 preferably with at least one cocatalyst component. The order in which the
 components are reacted is of no consequence. The reaction is carried out
 in a suitable solvent such as pentane, heptane, toluene, dichloromethane
 or dichlorobenzene in which the passivated support component is suspended
 and a solution of the metallocene and cocatalyst components is added
 dropwise, preferably by adding a solution of the metallocene and
 cocatalyst components in such an amount that the total solution volume is
 from 110 to 370% of the pore volume of the support component. The
 preparation of the catalyst system of the present invention is carried out
 at from -20 to 150.degree. C., preferably from 20 to 50.degree. C., and a
 contact time of from 15 minutes to 25 hours, preferably from 15 minutes to
 5 hours.
 The resulting catalyst system of the present invention has a metallocene
 content, preferably zirconium content, of from 0.001 to 2 mmol of
 Zr/g.sub.support, preferably from 0.01 to 0.5 mmol of zr/g.sub.support,
 particularly preferably from 0.01 to 0.1 mmol of Zr/g.sub.support, and an
 aluminum content of from 0.001 to 0.1 mol of Al/g.sub.support, preferably
 from 1 to 50 mmol of Al/g.sub.support. The aluminum/zirconium ratio is
 from 50:1 to 1000:1 (Al:Zr), preferably from 400:1 to 700:1 (Al:Zr).
 The catalyst system of the present invention gives polymers such as
 polypropylene having extraordinarily high stereospecificity and
 regiospecificity.
 Particularly characteristic for the stereospecificity and regiospecificity
 of polymers, in particular polypropylene, is, for example, the triad
 tacticity (TT) and the proportion of 2-1-inserted propene units (RI),
 which can be determined from the .sup.13 C-NMR spectra.
 The .sup.13 C-NMR spectra are me asured in a mixture of hexachlorobutadiene
 and d.sub.2 -tetrachloroethane at elevated temperature (365 K) . All
 .sup.13 C-NMR spectra of the polypropylene samples measured are calibrated
 to the resonance signal of d.sub.2 -tetrachloroethane (.delta.=73.81 ppm).
 The triad tacticity of the polypropylene is determined from the methyl
 resonance signals in the .sup.13 C-NMR spectrum between 23 and 16 ppm; cf.
 J. C. Randall, Polymer Sequence Determination: Carbon-13 NMR Method,
 Academic Press New York 1978; A. Zambelli, P. Locatelli, G. Bajo, F. A.
 Bovey, Macromolecules 8 (1975), 687-689; H. N. Cheng, J. A. Ewen,
 Makromol. Chem. 190(1989), 1931-1943. Three successive 1-2-inserted
 propene units whose methyl groups are arranged on the same side in the
 "Fischer projection" are referred to as mm triads (.delta.=21.0 ppm to
 22.0 ppm). If only the second methyl group of the three successive propene
 units points to the other side, the sequence is referred to as an rr triad
 (.delta.=19.5 ppm to 20.3 ppm) and if only the third methyl group of the
 three successive propene units points to the other side, the sequence is
 referred to as an mr triad (.delta.=20.3 ppm to 21.0 ppm). The triad
 tacticity is calculated according to the following formula:
EQU TT (%)=mm/(mm+mr+rr).multidot.100
 If a propene unit is inserted in reverse into the growing polymer chain,
 this is referred to as a 2-1 insertion; cf. T. Tsutsui, N. Ishimaru, A.
 Mizuno, A. Toyota, N. Kashiwa, Polymer 30, (1989), 1350-56. The following
 different structural arrangements are possible:
 ##STR7##
 The proportion of 2-1-inserted propene units (RI) can be calculated
 according to the following formula:
EQU RI(%)=0.5
 I.alpha.,.beta.(I.alpha.,.alpha.+I.alpha.,.beta.+I.alpha.,.delta.).multido
 t.100,
 where
 I.alpha.,.alpha. is the sum of the intensities of the resonance signals at
 .delta.=41.84, 42.92 and 46.22 ppm,
 I.alpha.,.beta. is the sum of the intensities of the resonance signals at
 .delta.=30.13, 32.12, 35.11 and 35.57 ppm
 and
 I.alpha.,.delta. is the intensity of the resonance signal at .delta.=37.08
 ppm.
 A particularly high regiospecificity also gives a particularly high melting
 point of the polymer, in particular the isotactic polypropylene. The
 isotactic polypropylene which has been prepared using the catalyst system
 of the present invention has a proportion of 2-1-inserted propene units
 RI&lt;0.2%, preferably &lt;0.1%, at a triad tacticity TT&gt;98.0% and a melting
 point &gt;158.degree. C., preferably &gt;160.degree. C., and the M.sub.w
 /M.sub.n of the polypropylene prepared according to the present invention
 is from 2.5 to 3.5.
 The present invention also provides a process for preparing a polyolefin by
 polymerization of one or more olefins in the presence of the catalyst
 system of the present invention comprising at least one passivated
 support. For the purposes of the present invention, the term
 polymerization means homopolymerization or copolymerization.
 Preference is given to polymerizing olefins of the formula R.sup.u
 --CH.dbd.CH--R.sup.v, where R.sup.u and R.sup.v are identical or different
 and are each a hydrogen atom or a carbon-containing radical having from 1
 to 20 carbon atoms, in particular from 1 to 10 carbon atoms, and R.sup.u
 and R.sup.v together with the atoms connecting them can form one or more
 rings. Examples of such olefins are 1-olefins having from 2 to 40,
 preferably from 2 to 10, carbon atoms, e.g. ethylene, propene, 1-butene,
 1-pentene, 1-hexene, 4-methyl-1-pentene or 1-octene, styrene, dienes such
 as 1,3-butadiene, 1,4-hexadiene, vinylnorbornene or norbornadiene and
 cyclic olefins such as norbornene, tetracyclododecene or methylnorbornene.
 In the process of the present invention, preference is given to
 homopolymerizing ethene or propene or copolymerizing ethene with one or
 more 1-olefins having from 3 to 20 carbon atoms, e.g. propene, and/or one
 or more dienes having from 4 to 20 carbon atoms, e.g. 1,4-butadiene or
 norbornadiene. Examples of such copolymers are ethene-propene copolymers
 and ethene-propene-1,4-hexadiene copolymers.
 The polymerization is preferably carried out at from -60 to 250.degree. C.,
 particularly preferably from 50 to 200.degree. C. The pressure is
 preferably from 0.5 to 2000 bar, particularly preferably from 5 to 64 bar.
 The polymerization time is from 10 minutes to 10 hours, preferably from 30
 minutes to 120 minutes.
 The polymerization can be carried out in solution, in bulk, in suspension
 or in the gas phase, continuously or batchwise, in one or more stages.
 The catalyst system used in the process of the present invention preferably
 comprises one transition metal compound of the metallocene component. It
 is also possible to use mixtures of two or more transition metal compounds
 of the metallocene component, e.g. for preparing polyolefins having a
 broad or multimodal molar mass distribution and reactor blends.
 A prepolymerization can be carried out by means of the catalyst system of
 the present invention. The prepolymerization is preferably carried out
 using the (or one of the) olefin(s) used in the polymerization.
 The supported catalyst system can be resuspended in an inert suspension
 medium either as powder or while still moist with solvent. The suspension
 can be introduced into the polymerization system.
 Before addition of the supported catalyst system of the present invention
 to the polymerization system, it is advantageous to purify the olefin
 using an aluminum alkyl compound such as trimethylaluminum,
 triethylaluminum, triisobutylaluminum, trioctylaluminum, isoprenylaluminum
 or aluminoxanes to make the polymerization system inert (for example to
 remove catalyst poisons present in the olefin). This purification can be
 carried out either in the polymerization system itself or the olefin is
 brought into contact with the Al compound and subsequently separated off
 again before addition to the polymerization system. If this purification
 is carried out in the polymerization system itself, the aluminum alkyl
 compound is added to the polymerizaiton system in a concentration of from
 0.01 to 100 mmol of Al per kg of reactor contents. Preference is given to
 using triisobutylaluminum and triethylaluminum in a concentration of from
 0.1 to 10 mmol of Al per kg of reactor contents.
 If necessary, hydrogen is added as molar mass regulator and/or to increase
 the activity. The total pressure in the polymerization system is from 0.5
 to 2500 bar, preferably from 2 to 1500 bar.
 The catalyst system is employed in a concentration, based on the transition
 metal, of preferably from 10.sup.-3 to 10.sup.-8 mol, particularly
 preferably from 10.sup.-4 to 10.sup.-7 mol, of transition metal per
 dm.sup.3 of solvent or per dm.sup.3 of reactor volume.
 If the polymerization is carried out as a suspension or solution
 polymerization, an inert solvent customary for the Ziegler low-pressure
 process is used. For example, the polymerization is carried out in an
 aliphatic or cycloaliphatic hydrocarbon, for example propane, butane,
 hexane, heptane, isooctane, cyclohexane or methylcyclohexane. It is also
 possible to use a petroleum or hydrogenated diesel oil fraction. Toluene
 can also be used. Preference is given to carrying out the polymerization
 in the liquid monomer.
 If inert solvents are used, the monomers are metered in in gaseous or
 liquid form.
 The duration of the polymerization can be as desired, since the catalyst
 system to be used according to the present invention displays only a
 slight time-dependent drop in the polymerization activity.
 The polymers prepared by the process of the present invention are
 particularly suitable for producing shaped bodies such as films, sheets or
 large hollow bodies (e.g. pipes).
 When using the catalyst system of the present invention, a catalyst
 activity of from 170 to 250 kg of PP/g of metallocene x h is achieved. The
 polymers of the present invention have melting points of from 158 to
 165.degree. C. The polymers of the present invention have triad
 tacticities of from 98.0 to 99.5% and reverse insertions of from 0.05 to
 0.12%.

EXAMPLES
 General procedures: The preparation and handling of the organometallic
 compounds was carried out with exclusion of air and moisture under argon
 (Schlenk technique). All solvents required were dried before use by
 boiling for a number of hours over a suitable desiccant and subsequent
 distillation under argon. The spherical, porous support materials used
 were silicas such as MS grades from PQ Corporation, ES or EP grades from
 Crosfield, or silica grades 948, 952, 955 from Grace Davisson or the like.
 The compounds were characterized using .sup.1 H-HMR [sic], .sup.13 C-NMR
 and IR spectroscopy.
 Example 1
 Passivation of the Support Material
 40 ml of 20% strength trimethylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (ES 70, Crosfield
 Catalysts, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried at 40.degree. C. in an oil pump vacuum.
 Preparation of the Supported Catalyst System
 In parallel thereto, 4.5 mg (7.2 .mu.mol) of
 dimethylsilanediyl-bis(2-methyl-4-phenylindenyl)zirconium dichloride were
 mixed with 10 cm.sup.3 of 30% strength (48.1 mmol) methylaluminoxane
 solution in toluene and an additional 1.5 cm.sup.3 of toluene and the
 mixture was stirred for 15 minutes.
 1 g of the passivated support material was resuspended in toluene and added
 dropwise to the above metallocene/methylaluminoxane solution. The reaction
 mixture was stirred for 30 minutes at room temperature. The mixture was
 subsequently filtered and the solid was washed 3 times with 10 cm.sup.3 of
 hexane. The hexane-moist filtration residue which remained was resuspended
 in 20 cm.sup.3 of hexane for the polymerization.
 Polymerization
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol)
 diluted with 30 cm.sup.3 of hexane were then introduced into the reactor
 and the mixture was stirred at 30.degree. C. for 15 minutes. The catalyst
 suspension was subsequently introduced into the reactor. The reaction
 mixture was heated to the polymerization temperature of 50.degree. C.
 (4.degree. C./min) and the polymerization system was held at 50.degree. C.
 for 1 hour by cooling. The polymerization was stopped by addition of 20
 cm.sup.3 of isopropanol. The excess monomer was vented, the polymer was
 dried under reduced pressure.
 This gave 1.01 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 242 kg of
 PP/g of metallocene.times.h.
 VN=793 cm.sup.3 /g; m.p.=160.degree. C.; M.sub.w =1,155,000; M.sub.w
 /M.sub.n =3.2;
 BD=356 d/dm.sup.3 [sic].
 Example 2
 The synthesis of the supported catalyst system of Example 1 was repeated,
 except that 5 cm.sup.3 of 30% strength (24 mmol) methyl-aluminoxane
 solution in toluene, 1.8 mg of
 dimethylsilanediyl-bis(2-methyl-4-phenylindenyl)zirconium dichloride (2.9
 .mu.mol of Zr) and 3 g of passivated support material were used. The
 polymerization was carried out using a method similar to Example 1 at
 70.degree. C. This gave 480 g of polypropylene powder. The reactor
 displayed no deposits on the inner wall or stirrer.
 The catalyst activity was 267 kg of PP/g of metallocene.times.h.
 VN=811 cm.sup.3 /g; m.p.=161.degree. C.; M.sub.w =1,182,000 g/mol; M.sub.w
 /M.sub.n =3.2;
 BD=343 g/dm.sup.3.
 Example 3
 The synthesis of the supported catalyst system of Example 1 was repeated,
 except that 70 cm.sup.3 of 30% strength (337 mmol) methylaluminoxane
 solution in toluene, 2.5 g of passivated support material and 44.2 mg of
 dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride (70.3
 .mu.mol of Zr) were used and the reaction mixture was stirred for 60
 minutes at room temperature. The solid was subsequently filtered off and
 washed 3 times with 50 cm.sup.3 of hexane.
 The hexane-moist filtration residue which remained was dried under reduced
 pressure to give a free-flowing, pale pink powder. This gave 5.36 g of
 supported, dry catalyst. For the polymerization, 2 g of this dry catalyst
 (16.5 mg=26.2 .mu.mol of Zr) were resuspended in 20 cm.sup.3 of hexane.
 The polymerization was carried out using a method similar to Example 1 at
 70.degree. C.
 This gave 3.93 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 238 kg of
 PP/g of metallocene.times.h. VN=824 cm.sup.3 /g; m.p.=160.degree. C.;
 M.sub.w =1,194,000 g/mol; M.sub.w /M.sub.n =3.0; BD=377 g/dm.sup.3.
 Example 4
 Passivation of the Support Material
 40 ml of 20% strength triisobutylalumnum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (ES 70, Crosfield
 Catalysts, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried in an oil pump vacuum.
 Preparation of the supported catalyst system
 In parallel thereto, 4.5 mg of
 dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride (7.2
 .mu.mol) were mixed with 1 cm.sup.3 of 30% strength (4.81 mmol)
 methylaluminoxane solution in toluene and an additional 2 cm.sup.3 of
 toluene and the mixture was stirred for 15 minutes. This
 metallocene/methylaluminoxane solution in toluene was then added dropwise
 to 1 g of passivated support material resuspended in toluene. The reaction
 mixture was stirred for 30 minutes at room temperature. The mixture was
 subsequently filtered and the solid was washed 3 times with 10 cm.sup.3 of
 hexane. The hexane-moist filtration residue which remained was resuspended
 in 20 cm.sup.3 of hexane for the polymerization.
 Polymerization
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes. The catalyst
 suspension was subsequently introduced into the reactor, the mixture was
 heated to the polymerization temperature of 50.degree. C. (4.degree.
 C./min) and the polymerization system was held at 50.degree. C. for 1 hour
 by cooling. The polymerization was stopped by addition of 20 cm.sup.3 of
 isopropanol. The excess monomer was vented, the polymer was dried under
 reduced pressure.
 This gave 895 g of polypropylene powder. The reactor displayed no deposits
 on the inner wall or stirrer. The catalyst activity was 199 kg of PP/g of
 metallocene.times.h.
 VN=812 cm.sup.3 /g; m.p.=161.degree. C.; M.sub.w =1,188,000 g/mol; M.sub.w
 /M.sub.n =3.3;
 BD=380 g/dm.sup.3.
 Example 5
 The synthesis of the supported catalyst system of Example 4 was repeated,
 except that 10 cm.sup.3 of 30% strength methylaluminoxane solution in
 toluene (48.1 mmol), 44.2 mg of
 dimethylsilane-diylbis(2-methyl-4-phenylindenyl)zirconium dichloride (70.3
 g [sic] .mu.mol of Zr) and 5 g of passivated support material were used
 and the reaction mixture was stirred for 60 minutes at room temperature.
 The solid was subsequently filtered off and washed 3 times with 50
 cm.sup.3 of hexane. The hexane-moist filtration residue which remained was
 dried under reduced pressure to give a free-flowing, pale pink powder.
 This gave 5.4 g of supported, dry catalyst.
 For the polymerization, 2 g of this dry catalyst (16.5 mg=26.2 .mu.mol of
 Zr) were resuspended in 20 cm.sup.3 of hexane.
 The polymerization was carried out using a method similar to Example 1 at
 70.degree. C.
 This gave 3.2 kg of polypropylene powder. The reactor displayed no deposits
 on the inner wall or stirrer. The catalyst activity was 194 kg of PP/g of
 metallocene.times.h. VN=907 cm.sup.3 /g; m.p.=162.degree. C.; M.sub.w
 =1,329,000 g/mol; M.sub.w /M.sub.n =3.3; BD =397 g/dm.sup.3.
 Example 6
 Passivation of the Support Material:
 40 ml of 20% strength trimethylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (PQ MS 3030, PQ
 Corporation, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried at room temperature in an oil pump vacuum. This gave 18 g of
 passivated support material. In parallel thereto, 4.5 mg (7.2 .mu.mol of
 Zr) of dimethylsilane-diylbis(2-methyl-4-phenylindenyl)zirconium
 dichloride were mixed with 1 cm.sup.3 of 30% strength (4.81 mmol)
 methylaluminoxane solution in toluene and the mixture was stirred for 15
 minutes. 1 g of the passivated support material was resuspended in toluene
 and the above metallocene/methylaluminoxane solution was added dropwise.
 The reaction mixture was stirred for 30 minutes at room temperature. The
 mixture was subsequently filtered and the solid was washed 3 times with 10
 cm.sup.3 of hexane. The hexane-moist filtration residue which remained was
 resuspended in 20 cm.sup.3 of hexane for the polymerization.
 Polymerization
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisoybutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes. The catalyst
 suspension was subsequently introduced into the reactor, the mixture was
 heated to the polymerization temperature of 50.degree. C. (4.degree.
 C./min) and the polymerization system was held at 50.degree. C. for 1 hour
 by cooling. The polymerization was stopped by addition of 20 cm.sup.3 of
 isopropanol. The excess monomer was vented, the polymer was dried under
 reduced pressure.
 This gave 990 g of polypropylene powder. The reactor displayed no deposits
 on the inner wall or stirrer. The catalyst activity was 220 kg of PP/g of
 metallocene.times.h. VN=868 cm.sup.3 /g; m.p.=160.degree. C.; M.sub.w
 =1,275,000 g/mol; M.sub.w /M.sub.n =3.4; BD=386 g/dm.sup.3.
 Example 7
 The synthesis of the supported catalyst system of Example 1 was repeated,
 except that 5 cm.sup.3 of 30% strength (24 mmol) methyl-aluminoxane
 solution in toluene, 1.8 mg of
 dimethylsilanediyl-bis(2-methyl-4-phenylindenyl)zirconium dichloride (2.9
 .mu.mol of Zr) and 3 g of passivated support material were used.
 The polymerization was carried out using a method similar to Example 1 at
 70.degree. C. This gave 369 g of polypropylene powder. The reactor
 displayed no deposits on the inner wall or stirrer.
 The catalyst activity was 205 kg of PP/g of metallocene.times.h.
 VN=842 cm.sup.3 /g; m.p.=160.degree. C.; M.sub.w =1,229,000 g/mol; M.sub.w
 /M.sub.n =3.2;
 BD=373 g/dm.sup.3.
 Example 8
 40 ml of 20% strength triisobutylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (PQ MS 3030, PQ
 Corporation, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried in an oil pump vacuum.
 Preparation of the Supported Catalyst System
 In parallel thereto, 20 mg (32 .mu.mol) of
 dimethylsilanediylbis-(2-methyl-4-phenylindenyl)zirconium dichloride were
 mixed with 3 cm.sup.3 of 30% strength (14.43 mmol) methylaluminoxane
 solution and a further 20 ml of toluene. The mixture was stirred for
 another 30 minutes.
 This metallocene/methylaluminoxane solution was then added dropwise while
 stirring vigorously to 5 g of the passivated support material and the
 mixture was stirred for another 15 minutes. The mixture was filtered and
 the solid was washed three times with 10 cm.sup.3 of hexane and dried in
 an oil pump vacuum. 20 ml of toluene were subsequently added and the
 catalyst system was resuspended.
 Polymerization
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes. The catalyst
 suspension was subsequently introduced into the reactor, the mixture was
 heated to the polymerization temperature of 70.degree. C. (4.degree.
 C./min) and the polymerization system was held at 70.degree. C. for 1 hour
 by cooling. The polymerization was stopped by addition of 20 cm.sup.3 of
 isopropanol. The excess monomer was vented, the polymer was dried under
 reduced pressure.
 This gave 2.86 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 143 kg of
 PP/g of metallocene.times.h. VN=946 cm.sup.3 /g; m.p.=162.degree. C.;
 M.sub.w =1,374,000 g/mol; M.sub.w /M.sub.n =3.0; BD=360 g/dm.sup.3.
 Example 9
 40 ml of 20% strength trimethylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (PQ MS 3030, PQ
 Corporation, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried in an oil pump vacuum.
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes.
 Preparation of the Supported Catalyst System
 20 mg (32 .mu.mol) of
 dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride were
 mixed with 3 ml of 30% strength (14.43 mmol) methylaluminoxane solution in
 toluene and a further 20 ml of toluene. The mixture was stirred for
 another 30 minutes at room temperature.
 This solution was then added dropwise to 5 g of passivated support
 material. The mixture was stirred for a further 15 minutes. under. [sic]
 The mixture was subsequently filtered and the solid was washed three times
 with 10 cm.sup.3 of hexane. The hexane-moist filtration residue which
 remained was resuspended in 20 cm.sup.3 of toluene for the polymerization.
 The catalyst suspension was subsequently introduced into the reactor, the
 mixture was heated to the polymerization temperature of 20.degree. C.
 (4.degree. C./min) and the polymerization system was heated [sic] at
 70.degree. C. for 1 hour by cooling. The polymerization was stopped by
 addition of 20 cm.sup.3 of isopropanol. The excess monomer was vented, the
 polymer was dried under reduced pressure.
 This gave 2.94 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 147 kg of
 PP/Kg [sic] of metallocene.times.h. VN=842 cm.sup.3 /g; m.p.=160.degree.
 C., M.sub.w =1,217,000 g/mol; M.sub.w /M.sub.n =2.9; BD=356 g/dm.sup.3.
 Example 10
 40 ml of 20% strength triisobutylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (PMQS 3030, PQ
 Corporation, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried in an oil pump vacuum. In parallel thereto, a dry 16 dm.sup.3
 reactor was flushed first with nitrogen and subsequently with propylene
 and charged with 10 dm.sup.3 of liquid propylene. 3 cm.sup.3 of
 triisobutylaluminum (pure, 12 mmol) were then diluted with 30 cm.sup.3 of
 hexane, introduced into the reactor and the mixture was stirred at
 30.degree. C. for 15 minutes.
 Preparation of the Supported Catalyst System
 20 mg (32 .mu.mol) of
 dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride were
 mixed with 3 ml of 30% strength (14.43 mmol) methylaluminoxane solution in
 toluene and a further 20 ml of toluene. The mixture was stirred for
 another 60 minutes at room temperature. This solution was then added
 dropwise to 2 g of passivated support material. The mixture was stirred
 for a further 15 minutes.
 The mixture was subsequently filtered and the solid was washed once with 10
 cm.sup.3 of hexane. The hexane-moist residue which remained was dried in
 an oil pump vacuum and then resuspended in 20 cm.sup.3 of toluene.
 The catalyst suspension was subsequently introduced into the reactor, the
 mixture was heated to the polymerization temperature of 20.degree. C.
 (4.degree. C./min) and the polymerization system was heated [sic] at
 70.degree. C. for 1 hour by cooling. The polymerization was stopped by
 addition of 20 cm.sup.3 of isopropanol. The excess monomer was vented, the
 polymer was dried under reduced pressure.
 This gave 3.26 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 163 kg of
 PP/g. VN=910 cm.sup.3 /g; m.p.=162.degree. C.; M.sub.w =1,323,000 g/mol;
 M.sub.w /M.sub.n =3.0; BD=340 g/dm.sup.3.
 Example 11
 40 ml of 20% strength trimethylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (PMQS 3030, PQ
 Corporation, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried in an oil pump vacuum.
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes.
 Preparation of the Supported Catalyst System
 20 mg (32 .mu.mol) of
 dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride were
 mixed with 3 ml of 30% strength (14.43 mmol) methylaluminoxane solution in
 toluene and a further 20 ml of toluene. The mixture was stirred for
 another 30 minutes at room temperature.
 This solution was then added dropwise to 2 g of passivated support
 material. The mixture was stirred for a further 15 minutes.
 The mixture was subsequently filtered and the solid was washed once with 10
 cm.sup.3 of hexane. The hexane-moist residue which remained was dried in
 an oil pump vacuum and then resuspended in 20 cm.sup.3 of hexane.
 The catalyst suspension was subsequently introduced into the reactor, the
 mixture was heated to the polymerization temperature of 20.degree. C.
 (4.degree. C./min) and the polymerization system was heated [sic] at
 70.degree. C. for 1 hour by cooling. The polymerization was stopped by
 addition of 20 cm.sup.3 of isopropanol. The excess monomer was vented, the
 polymer was dried under reduced pressure.
 This gave 3.3 kg of polypropylene powder. The reactor displayed no deposits
 on the inner wall or stirrer. The catalyst activity was 165 kg of PP/g.
 VN=874 cm.sup.3 /g; m.p.=160.degree. C.; M.sub.w =1,254,000 g/mol; M.sub.w
 /M.sub.n =2.9; BD=375 g/dm.sup.3.
 Example 12
 40 ml of 20% strength trimethylaluminum solution in Varsol were slowly
 added dropwise while stirring to 10 g of SiO.sub.2 (PMQS 3030, PQ
 Corporation, dried at 140.degree. C. and 10 mbar). Sufficient toluene to
 form a readily stirrable suspension was then added. The mixture was
 stirred for another 10 minutes and the solid was then filtered off from
 the solvent. The filtration residue was washed twice with 10 ml of
 toluene. The support material which had been pretreated in this way was
 dried in an oil pump vacuum.
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes.
 Preparation of the Supported Catalyst System
 20 mg (32 .mu.mol) of
 dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride were
 mixed with 3 ml of 30% strength (14.43 mmol) methylaluminoxane solution in
 toluene and a further 6 ml of toluene. The mixture was stirred for another
 30 minutes at room temperature.
 This solution was then added dropwise to 2 g of passivated support
 material. The mixture was stirred for a further 15 minutes and the
 catalyst system was resuspended in 20 ml of toluene.
 The catalyst suspension was subsequently introduced into the reactor, the
 mixture was heated to the polymerization temperature of 20.degree. C.
 (4.degree. C./min) and the polymerization system was heated [sic] at
 70.degree. C. for 1 hour by cooling. The polymerization was stopped by
 addition of 20 cm.sup.3 of isopropanol. The excess monomer was vented, the
 polymer was dried under reduced pressure.
 This gave 3.42 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 171 kg of
 PP/g. VN=868 cm.sup.3 /g; m.p.=161.degree. C.; M.sub.w =1,254,000 g/mol;
 M.sub.w /M.sub.n =3.2; BD=360 g/dm.sup.3.
 As Comparative Examples 1 to 3, the Examples 3, 4 and 5 from the Patent
 Application EP 576 970 A1 have been incorporated into the present
 description.
 Comparative Example 1
 22 cm.sup.3 of the suspension of the "MAO on SiO.sub.2 " (49 mmol of Al)
 were introduced under argon into a G3 Schlenk frit and admixed with a
 solution of 4.5 mg of
 dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride in 10
 cm.sup.3 of toluene (7.2 .mu.mol of Zr).
 The reaction mixture was stirred at room temperature for 30 minutes, with a
 spontaneous color change to red gradually becoming paler. The mixture was
 subsequently filtered and the solid was washed 3 times with 10 cm.sup.3 of
 hexane. The hexane-moist filtration residue which remained was resuspended
 in 20 cm.sup.3 of hexane for the polymerization.
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol) were
 then diluted with 30 cm.sup.3 of hexane, introduced into the reactor and
 the mixture was stirred at 30.degree. C. for 15 minutes. The catalyst
 suspension was subsequently introduced into the reactor, the mixture was
 heated to the polymerization temperature of 50.degree. C. (4.degree.
 C./min) and the polymerization system was held at 50.degree. C. for 1 hour
 by cooling. The polymerization was stopped by addition of 20 cm.sup.3 of
 isopropanol. The excess monomer was vented, the polymer was dried under
 reduced pressure.
 This gave 300 g of polypropylene powder. The reactor displayed no deposits
 on the inner wall or stirrer. The catalyst activity was 67 kg of PP/g of
 metallocene.times.h. VN=1380 cm.sup.3 /g; m.p.=156.degree. C.
 Comparative Example 2
 The synthesis of the supported catalyst system of Comparative Example 1 was
 repeated, except that 13 cm.sup.3 (29 mmol of Al) of the suspension of
 "MAO on SiO.sub.2 " and 1.8 mg of rac-5 (2.9 .mu.mol of Zr) were used.
 The polymerization was carried out using a method similar to Comparative
 Example 1 at 70.degree. C. This gave 420 g of polypropylene powder. The
 reactor showed no deposits on the inner wall or stirrer. The catalyst
 activity was 233 kg of PP/g of metallocene.times.h. VN=787 cm.sup.3 /g;
 m.p.=149.5.degree. C.
 Comparative Example 3
 40 The synthesis of the supported catalyst system of Comparative Example 1
 was repeated, except that 150 cm.sup.3 (335 mmol of Al) of the suspension
 of "MAO on SiO.sub.2 " and 44.2 mg (70.3 .mu.mol of Zr) were used and the
 reaction mixture was stirred for 60 minutes at room temperature.
 The solid was subsequently filtered off and washed 3 times with 50 cm.sup.3
 of hexane. The hexane-moist filtration residue which remained was dried
 under reduced pressure to give a free-flowing, pale pink powder. This gave
 33.3 g of supported, dry catalyst. For the polymerization, 2.98 g (4 mg
 =6.3 .mu.mol of Zr) of this dry catalyst were resuspended in 20 cm.sup.3
 of hexane.
 The polymerization was carried out using a method similar to Comparative
 Example 1 at 70.degree. C.
 This gave 1.05 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 263 kg of
 PP/g of metallocene.times.h. VN=944 cm.sup.3 /g; m.p.=156.degree.m C.
 Comparative Example 4
 Preparation of the Supported Catalyst System
 6.5 cm.sup.3 of the suspension of "MAO on SiO.sub.2 " (14.4 mmol of Al)
 were introduced into a G3 Schlenk frit and mixed with a solution of 20 mg
 (32 .mu.mol) of dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium
 dichloride in 10 cm.sup.3 of toluene and a further 20 ml of toluene. The
 mixture was stirred for another 30 minutes at room temperature.
 The mixture was subsequently filtered and the solid was washed three times
 with 10 cm.sup.3 of hexane. The hexane-moist filtration residue which
 remained was resuspended in 20 cm.sup.3 of hexane for the polymerization.
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 3 cm.sup.3 of triisobutylaluminum (pure, 12 mmol)
 diluted with 30 cm.sup.3 of hexane were then introduced into the reactor
 and the mixture was stirred at 30.degree. C. for 15 minutes.
 The catalyst suspension was subsequently introduced into the reactor, the
 mixture was heated to the polymerization temperature of 20.degree. C.
 (4.degree. C./min) and the polymerization system was heated [sic] at
 70.degree. C. for 1 hour by cooling. The polymerization was stopped by
 addition of 20 cm.sup.3 of isopropanol. The excess monomer was vented, the
 polymer was dried under reduced pressure.
 This gave 3.45 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 172 kg of
 PP/g of metallocene.times.h. M.p.=149.degree. C.; VN=872 cm.sup.3 /g;
 M.sub.w =1,290,000 g/mol; M.sub.w /M.sub.n =2.9; BD=410 g/dm.sup.3.
 Comparative Example 5
 Preparation of the Supported Catalyst System
 5 g of SiO.sub.2 (PQMS 3030, PQ Corporation, dried at 140.degree. C. and 10
 mbar) were suspended in 30 ml of toluene and admixed with the following
 metallocene/MAO/toluene solution.
 20 mg (32 .mu.mol) of
 dimethylsilanediylbis(2-methyl-4-phenyl-indenyl)zirconium dichloride were
 mixed with 3 ml of 30% strength (14.43 mmol) methylaluminoxane solution in
 toluene and a further 10 ml of toluene. The mixture was stirred for
 another 30 minutes at room temperature.
 In parallel thereto, a dry 16 dm.sup.3 reactor was flushed first with
 nitrogen and subsequently with propylene and charged with 10 dm.sup.3 of
 liquid propylene. 13 cm.sup.3 instead of 3 cm.sup.3 of 20% strength
 triisobutylaluminum solution in vargol [sic] were then introduced into the
 reactor and the mixture was stirred at 30.degree. C. for 15 minutes.
 The catalyst suspension was subsequently introduced into the reactor, the
 mixture was heated to the polymerization temperature of 20.degree. C.
 (4.degree. C./min) and the polymerization system was heated [sic] at
 70.degree. C. for 1 hour by cooling. The polymerization was stopped by
 addition of 20 cm.sup.3 of isopropanol. The excess monomer was vented, the
 polymer was dried under reduced pressure.
 This gave 3.58 kg of polypropylene powder. The reactor displayed no
 deposits on the inner wall or stirrer. The catalyst activity was 179 kg of
 PP/g. VN=910 cm.sup.3 /g; m.p.=149.degree. C.; M.sub.w =1,328,0000 [sic]
 g/mol; M.sub.w /M.sub.n =3.3; BD=95 g/dm.sup.3.
 Table 2 below indicates which examples are compared with which comparative
 examples.
 TABLE 2
 Examples Comparative Example
 1, 4, 6 1
 2, 7 2
 3, 5 3
 8, 9, 10, 11, 12 4, 5
 Table 3 below shows the characteristic data of the catalyst system and the
 polymers obtained.
 TABLE 3
 Exam-
 ples (E)
 Com-
 parative Cat.
 Exam- activ-
 ples (C) ity.sup.1 VN.sup.2 m.p..sup.3 M.sub.w.sup.3 M.sub.w
 /M.sub.n.sup.5 BD.sup.6 TT.sup.7 RI.sup.8
 E1 242 793 160 1155000 3.2 356 98.2 0.09
 E2 267 811 161 1182000 3.2 343 98.7 0.09
 E3 238 824 160 1194000 3.0 377 98.2 0.11
 E4 199 812 161 1188000 3.3 380 99.3 0.10
 E5 194 907 162 1329000 3.3 397 99.5 0.07
 E6 220 868 160 1275000 3.4 386 98.5 0.08
 E7 205 842 160 1229000 3.2 373 98.2 0.09
 E8 143 946 162 1374000 3.0 360 99.5 0.06
 E9 147 842 160 1217000 2.9 356 98.9 0.10
 E10 163 910 162 1323000 3.0 340 99.1 0.09
 E11 165 874 160 1254000 2.9 375 99.2 0.11
 E12 171 868 161 125000 3.2 360 98.5 0.06
 C1 67 1380 156 -- -- -- -- --
 C2 223 787 149.5 -- -- -- -- --
 C3 263 944 156 -- -- -- -- --
 C4 172 872 149 1290000 2.9 410 94.7 0.43
 C5 179 910 149 1328000 3.3 395 95.4 0.49
 .sup.1 Catalyst activity in kg of PP/g of metallocene .times. h
 .sup.2 Viscosity number in cm.sup.3 /g
 .sup.3 Melting point in .degree. C.; determined using DSC, 20.degree.
 C./min heating/cooling rate; second heating
 .sup.4 Weight average molar mass in g/mol; determined by gel permeation
 chromatography
 .sup.5 Polydispersity
 .sup.6 Polymer bulk density in g/dm.sup.3
 .sup.7 Triad tacticity TT = mm/(mm + mr + rr) .multidot. 100 in %;
 determined by .sup.13 C-NMR spectroscopy
 .sup.8 Reverse insertions in %; determined by .sup.13 C-NMR spectroscopy
 1) Catalyst activity in kg of PP/g of metallocene.times.h
 2) Viscosity number in cm.sup.3 /g
 3) Melting point in .degree. C.; determined using DSC, 20.degree. C./min
 heating/cooling rate; second heating
 4) Weight average molar mass in g/mol; determined by gel permeation
 chromatography
 5) Polydispersity
 6) Polymer bulk density in g/dm.sup.3
 7) Triad tacticity TT=mm/(mm+mr+rr).multidot.100 in %; determined by
 .sup.13 C-NMR spectroscopy
 8) Reverse insertions in %; determined by .sup.13 C-NMR spectroscopy
 Comparison of the Examples E1 to E12 carried out according to the present
 invention with the Examples C1 to C4 carried out according to the prior
 art shows the following advantages of the invention.
 1. Polymers of the invention having melting points of from 160.degree. C.
 to 162.degree. C. compared to 149.degree. C. to 156.degree. C. were
 obtained.
 2. The proportion of 2-1-inserted propene units (RI) was significantly
 lower in the polymers of the present invention.
 Comparison of Examples E1 to E12 with Comparative Example C5 showed that
 polymers having high melting points (.gtoreq.160.degree. C.) were obtained
 only when using passivated support material.