WO1999061490A1

WO1999061490A1 - Suspension phase method for polymerising ethylene

Info

Publication number: WO1999061490A1
Application number: PCT/EP1999/003417
Authority: WO
Inventors: Stefan Mecking
Original assignee: Axiva Gmbh
Priority date: 1998-05-28
Filing date: 1999-05-18
Publication date: 1999-12-02
Also published as: DE19823871A1

Abstract

The invention relates to a suspension method for polymerising ethylene using catalyst compositions containing a polymerisation catalyst based on a late transition metal component and at least one other polymerisation catalyst based on an early or late transition metal component.

Description

description

Suspension phase process for the polymerization of ethylene.

The present invention relates to a suspension process for the polymerization of ethylene using catalyst compositions comprising a polymerization catalyst based on a late transition metal component and at least one further polymerization catalyst based on a transition metal component.

The use of Ziegler-type or metallocene-type catalysts for the polymerization of non-polar olefins such as ethylene and propylene is known. Such catalysts usually consist of an early transition metal compound, for example a titanium or zirconium compound containing halide, in combination with an excess of a cocatalyst

Example of an aluminum connection. More recently, the activation of suitable transition metal compounds with stoichiometric amounts of a cocatalyst, such as a [Ph ₃ C] ⁺ or [Me ₂ NPh] ⁺ salt of a non-coordinating anion, has been described.

The use of catalyst compositions which contain two or more different olefin polymerization catalysts of the Ziegler type or of the metallocene type is known. For example, WO-95 / 11,264 describes the combination of two catalysts, one of which produces a polyethylene of different average molecular weight than the other

Representation of reactor blends with broad molecular weight distributions. The polymer blends obtained show improved processing and use properties.

For setting the usage and processing properties of

Polyethylene is often desirable to introduce branching. The use of bimetallic catalysts for the polymerization of ethylene to branched polymers, with oligomerization of part of the ethylene by a catalyst component, and copolymerization of the oligomers thus formed with ethylene by the other catalyst component is known (cf. Beach, David L; Kissin, Yury V .; J. Polym. Be., Polym. Chem. Ed. 1984, 22, 3027-42. Ostoja-Starzewski, KA; Witte, J .; Reichert, KH, Vasiliou, G. in Transition Metals and Organometallics as Catalysts for Olefin Polymerization. Kaminsky, W .; Sinn, H. (ed.); Springer publishing house; Heidelberg; 1988; Pp. 349-360). The latter reference describes e.g. B. the use of a nickel-containing oligomerization catalyst in combination with a chromium-containing polymerization catalyst. In this way, branched polyolefins can be produced from ethylene without the need for additional comonomers. However, the activity of the nickel component is unsatisfactorily low compared to Ziegler or metallocene catalysts.

In WO-96 / 23,010 Brookhart et al. Catalysts for the polymerization of ethylene and α-olefins, which are based on late transition metals such as nickel or palladium. With these highly active catalysts, a highly branched homopolymer can be obtained from ethylene without the addition of a comonomer.

WO-97 / 48,735 and WO-97 / 38,024 as well as the as yet unpublished German patent application P19707236.4 describe polymerization catalysts which contain an early transition metal component, i.e. a metallocene or a Ziegler catalyst, and a late transition metal component, preferably that in

WO-96 / 23,010 listed. It can be used, for example, to produce reactor blends of linear and branched ethylene homopolymers from ethylene. These show advantageous usage properties.

Owing to their branching structure, the ethylene homopolymers obtained with polymerization catalysts based on late transition metals, such as the catalysts described in WO-96 / 23,010, in contrast to conventional ethylene homopolymers obtained with metallocene or Ziegler catalysts, when the polymerization is carried out in the liquid phase conventional reaction media, such as hexane or toluene, form a solution in the reaction medium even at temperatures below 100 ° C., as are customary for customary technical suspension processes. In the case of reactor blend processes using such catalysts in a liquid phase process, this can lead to their separation due to the different solubility of the components of the polymer mixture obtained. Thus, in WO-97 / 48,735 and WO-97 / 38,024 as well as the as yet unpublished German patent application P 19707236.4, the reaction mixtures obtained from the polymerization in reaction media such as toluene or hexane are not directly subjected to filtration or centrifugation to separate the polymer from the reaction medium, but first in a larger quantity

Precipitant, for example acetone or methanol poured in, or the reaction medium is removed under vacuum. The dissolution of part of the polymer product in the reaction medium is usually disadvantageous, since the work-up following the polymerization and the polymerization process itself become more complex and therefore more uneconomical. It will also be a good one

Mixing of the polymers, which is fundamentally favored by the simultaneous formation in the polymerization reactor, annihilated.

The object of the present invention was to provide a method which avoids the disadvantages mentioned above.

It has surprisingly been found that this object can be achieved by using certain selected catalyst compositions and under certain selected polymerization conditions.

The present invention thus relates to a suspension polymerization process for the production of polyethylene by polymerizing ethylene in the presence of a catalyst composition

A) at least one polymerization catalyst based on a late transition metal component, which produces a polyethylene with a degree of branching of 0-40 branches, preferably 2-35, particularly preferably 5-15, per 1000 methylene groups and

B) at least one further polymerization catalyst based on an early or late transition metal, and the polymerization is carried out in the presence of a medium which is liquid under the reaction conditions and under elevated pressure, and the resulting polymer is separated from the liquid reaction medium without the addition of precipitants.

With the aid of the method according to the invention, it is possible to obtain the polymer obtained, which completely precipitates out of the reaction medium during the polymerization without isolating the disadvantages described above.

The term precipitant is understood to mean those which reduce the solubility of the polymer in the liquid reaction medium.

Complete precipitation means that after the end of the polymerization reaction the reaction medium contains less than 15% (based on the total amount of ethylene converted), preferably less than 5%, of compounds formed by oligomerization or polymerization in solution.

The polymerization of ethylene is understood to mean the conversion to polymers which in total contain a maximum of 3% by weight of one or more olefinic comonomers; under polyethylene a polymer obtained by the polymerization of ethylene according to the invention. Under the homopolymerization of

Ethylene means the polymerization of ethylene without the addition of comonomers, ethylene homopolymer is a polymer obtained by the homopolymerization according to the invention.

An early transition metal is understood to mean the metals from the groups purple to VIIa of the periodic table of the elements and the metals from the group of the lanthanoids.

A late transition metal is understood to mean the metals of the Villa and IB groups of the Periodic Table of the Elements. The catalyst composition used according to the invention contains at least two polymerization catalysts, at least one of which is a polymerization catalyst based on a late transition metal component, which produces a polyethylene with a degree of branching of 0-40, preferably 2-35, particularly preferably 5-15. Each transition metal component contains exactly one transition metal.

As the catalyst component based on a late transition metal, the catalyst composition used according to the invention preferably contains a nickel, palladium, platinum, iron, ruthenium, cobalt or rhodium compound, particularly preferably a nickel, iron or palladium compound. The late transition metal compound preferably contains exclusively or in combination with other ligands, those ligands which coordinate to the metal in a chelating manner via two or more atoms. The two coordinating atoms are preferably nitrogen atoms. Ligands of the following formulas II and / or III are particularly preferred

R7

(II) (III) wherein

R ⁷ , R ^{8 are} independently the same or different

hydrogen radicals, in which the carbon atom bonded to the nitrogen atom is preferably connected to at least two further carbon atoms. R ⁷ and R ⁸ are preferably C ₆ -C ₂₀ aryl radicals which are preferably substituted in both ortho positions, e.g. B. with CC ₁₀ alkyl radicals such as methyl or isopropyl. R ⁹ , R ^10, independently of one another, the same or different, form a hydrogen atom or a C-rC.jo hydrocarbon radical, such as C ₁ -C ₂₀ alkyl or C ₆ -C ₂₀ aryl, or R ⁹ and R ⁰ together form a ring system, which is preferably derived from acenaphtenquinone.

Nickel or palladium compounds are particularly preferred, especially in the

Oxidation levels zero or two and with the ligands of the formula II, and iron compounds with ligands of the formula IM.

As the catalyst component based on a late transition metal, the catalyst composition according to the invention preferably contains the nickel or palladium compounds mentioned in WO-96 / 23,010, which have a bidentate ligand coordinating via nitrogen atoms and are likewise part of the present description.

The late transition metal component may already contain the ligand coordinating with the metal, or it may be obtained by combining one suitable transition metal component with the free ligand or a ligand derivative "in situ" (ie in the polymerization reactor).

Examples of particularly suitable late transition metal components are listed below. The term "An" refers to ligands in which the radicals R ⁹ and R ^{10 form} a ring system derived from acenaphtenquinone, which are represented in the following formula:

In the list below, Me = methyl, Et = ethyl and Pr = isopropyl.

The exemplary late transition metal compounds are: ϊ {(2,6- ⁱ Pr ₂ C ₆ H ₃ ) -N = C (H) -C (H) = N- (2,6- ⁱ Pr ₂ C ₆ H ₃ )} NiBr ₂ ]

K (2,6-Me ₂ C ₆ H ₃ ) -N = C (H) -C (H) = N- (2,6-Me ₂ C ₆ H ₃ )} NiBr ₂ ] [{(2,6 -Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6-Me ₂ C ₆ H ₃ )} NiBr ₂ ]

[{(2,6-Me ₂ C ₆ H ₃ ) -N = C (An) -C (An) = N- (2,6-Me ₂ C ₆ H ₃ )} NiBr ₂ ]

[{(2,6- ⁱ Pr ₂ C ₆ H ₃ ) -N = C (H) -C (H) = N- (2,6- ⁱ Pr ₂ C ₆ H ₃ )} NiMe ₂ ]

[{(2,6-Me ₂ C ₆ H ₃ ) -N = C (H) -C (H) = N- (2,6- ⁱ Me ₂ C ₆ H ₃ )} NiMe ₂ ]

I {(2,6-Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6-Me ₂ C ₆ H ₃ )} NiMe ₂ ] [{(2, 6-Me ₂ C ₆ H ₃ ) -N = C (An) -C (An) = N- (2,6-Me ₂ C ₆ H ₃ )} NiMe ₂ ]

[{2,6 - {(2,6- ⁱ Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} FeBr ₂ ]

[{2,6 - {(2,6- Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} FeBr ₃ ]

[{2,6 - {(2,6-Me ₂ C _e H ₃ ) -N = C (Me)} ₂ pyridine} FeBr ₂ ]

[{2,6 - {(2 ₎ 6-Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} CoBr ₂ ] I {2,6 - {(2,6-Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} CoBr ₃ ] ϊ {2.6 - {(2 ₁ 6-Me ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} CoBr ₂ ]

[{2,6 - {(2,6-Me ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} CoBr ₃ ]

Instead of the dibromides listed, the corresponding compounds in which one or both of the bromide ligands are replaced by chloride, iodide or methyl are used. The catalyst composition contains at least one further catalyst component. This is a catalyst component based on an early transition metal, or a further catalyst component based on a late transition metal according to the above

Description.

As a catalyst component based on an early transition metal, the catalyst composition used according to the invention preferably contains so-called Ziegler catalyst components (as described, for example, in Falbe, J .; Regitz, M.

(Ed.); Römpp Chemie Lexicon; 9th edition; Thieme; 1992; New York; Vol. 6, pp. 5128 - 5129 or Diederich, B .; Appl. Polym. Symp. 1975, 26, 1-11 or BE737778 (1968)) and / or Metailocen catalyst components. Metallocene catalyst components are preferred. The Ziegler catalyst component is preferably a

Compound of a Group IVa metal (e.g. titanium, zirconium or hafnium), Va (e.g. vanadium or niobium) or via (e.g. chromium or molybdenum) of the Periodic Table of the Elements. Halides, oxides, oxyhalides, hydroxides or alkoxides are preferred. Exemplary but non-limiting examples of Ziegler catalyst components are: titanium tetrachloride, zircon tetrachloride,

Hafnium tetrachloride, titanium trichloride, vanadium trichloride, vanadium oxychloride, chromium trichloride or chromium oxide.

As metallocene catalyst components such. B. understood cyclopentadienyl complexes. Cyclopentadienyl complexes of metals from the purple group and the group of lanthanoids (e.g. lanthanum or yttrium) are preferred, as are metals from group IVa (e.g. titanium, zirconium or hafnium), Va (e.g. vanadium or niobium) or Via the periodic table of the elements (e.g. chromium or molybdenum), cyclopentadienyl complexes of titanium, zirconium or hafnium are particularly preferred. The cyclopentadienyl complexes can e.g. B. bridged or unbridged

Biscyclopentadienylkomplexe, as z. B. in EP-A-0, 129.368, EP-A-0.561, 479, EP-A-0.545.304 and EP-A-0.576.970, monocyclopentadienyl complexes such as bridged amidocyclopentadienyl complexes z. B. are described in EP-A-0,416,815, polynuclear cyclopentadienyl complexes as described in EP-A- 0,632,063, π-ligand-substituted tetrahydropentalenes as in EP-A- 0,659,758 or π-ligand-substituted tetrahydroindenes as described in EP-A-0,661,300.

Preferred metallocene catalyst components are unbridged or bridged metallocene compounds of the formula I,

where M ^{1 is} a metal from the group purple, IVa, Va or Via of the Periodic Table of the Elements, in particular Ti, Zr or Hf,

R ¹ are identical or different and are a hydrogen atom or SiR ₃ ^3, where R ³ are identical or different, represent a hydrogen atom or a C C. ₄ 0 carbon-containing group such as CC ₂ -alkyl, C _r C ₁₀ fluoroalkyl, C ₁ -C ₁₀ -alkoxy, C ₆ -C ₂₀ aryl, C ₆ -C ₁₀ fluoroaryl, C ₆ -C ₁₀ aryloxy, C ₂ -C ₁₀ alkenyl, C ₇ -C ₄₀ arylalkyl, C ₇ -C ₄₀ - Are alkylaryl or C ₈ -C ₄₀ arylalkenyl, or R ¹ are a C _r C ₃₀ - carbon-containing group such as CC ₂₅ alkyl, e.g. B. methyl, ethyl, tert-butyl, cyclohexyl or octyl, C ₂ -C ₂₅ alkenyl, C ₃ -C ₁₅ alkylalkenyl, C ₆ -C ₂₄ aryl, C ₅ -C ₂₄ - heteroaryl such as pyridyl, furyl or quinolyl, C ₇ -C ₃₀ arylalkyl, C ₇ -C ₃₀ alkylaryl, fluorine-containing CC ₂₅ alkyl, fluorine-containing C ₆ -C ₂₄ aryl, fluorine-containing C ₇ -C ₃₀ arylalkyl, fluorine-containing C ₇ -C ₃₀ - Alkylaryl or C _r C ₁₂ alkoxy, or two or more radicals R ¹ can be connected to one another such that the radicals R ¹ and the atoms of the cyclopentadienyl ring connecting them form a C ₄ -C ₂₄ ring system, which in turn can be substituted , is 5 for v = 0, and I is 4 for v = 1, either a) an element of V. (e.g. nitrogen or phosphorus) or VI. (e.g.

Oxygen or sulfur) main group of the periodic table of the

Elements which is one or two CC ₂₀ -

Carries hydrocarbon substituents such as C _r C ₁₀ alkyl or C ₆ -C ₂₀ aryl, or b) a residue of the formula

wherein R ^{2 are the} same or different and is a hydrogen atom or

Are SiR ₃ ³ , in which R ^3, identical or different, represents a hydrogen atom or a C 1 -C 4 -carbon-containing group such as C _r C ₂₀ alkyl, C _r C ₁₀ fluoroalkyl, C _r C ₁₀ alkoxy, C ₆ -C ₁₄ - Aryl, C ₆ -C ₁₀ fluoroaryl, C ₆ -C ₁₀ aryloxy, C ₂ -C ₁₀ alkenyl, C ₇ -C ₄₀ arylalkyl, C ₇ -C ₄₀ alkylaryl or C ₈ -C ₄₀ arylalkenyl , or R ² are a C, -C ₃₀ - carbon-containing group such as C _r C ₂₅ alkyl, e.g. B. methyl, ethyl, tert-butyl, cyclohexyl or octyl, C ₂ -C ₂₅ alkenyl, C ₃ -C ₁₅ alkylalkenyl, C ₆ -C ₂₄ aryl, C ₅ -C ₂₄ heteroaryl, e.g. B. pyridyl, furyl or quinolyl, C ₇ -C ₃₀ arylalkyl, C ₇ -C ₃₀ alkylaryl, fluorine-containing C _r C ₂₅ alkyl, fluorine-containing C ₆ -C ₂₄ aryl, fluorine-containing C ₇ -C ₃₀ arylalkyl, is fluorine-containing C ₇ -C ₃₀ alkylaryl or C, -C ₁₂ alkoxy, or two or more radicals R ² can be bonded to one another in such a way that the radicals R ² and the atoms of the cyclopentadienyl ring connecting them form a C ₄ -C ₂₄ - Form ring system, which in turn can be substituted, and m is 5 for v = 0, and m is 4 for v = 1, L ^{1 can be the} same or different and a hydrogen atom, a C _r C ₂₀ - hydrocarbon radical such as CC ₁₀ - Alkyl or C ₆ -C ₂₀ aryl, a halogen atom, or OR ⁶ , SR ⁶ , OSiR ₃ ⁶ , SiR ₃ ⁶ , PR ₂ ⁶ or NR ₂ ⁶ , wherein R ^{6 is} a halogen atom, a CC ₁₀ alkyl group, a halogenated C ^ C ^ alkyl group, a C ₆ -C ₂₀ aryl group or a halogenated C ₆ -C ₂₀ aryl group, or L ¹ are a toluenesulfonyl, trifluoroacetyl, trifluoroacetoxyl, trifluorometha nsulfonyl, nonafluorobutanesulfonyl or 2,2,2-trifluoroethanesulfonyl group, o is an integer from 1 to 4, preferably 2,

Z denotes a bridging structural element between the two cyclopentadienyl rings and v is 0 or 1. Examples of Z are groups (M ² RR ⁵ ) _X , in which M ^{2 is} carbon, silicon, germanium or tin, x is 1, 2 or 3, and R ⁴ and R ^{5 are} identical or different and are a hydrogen atom or a C 1 -C 6 hydrocarbon-containing group such as C ₁ -C ₁₀ alkyl, C ₆ -C ₁₄ aryl or trimethylsilyl. Z is preferably CH ₂ , CH ₂ CH ₂ , CH (CH ₃ ) CH ₂ , CH (C ₄ H ₉ ) C (CH ₃ ) ₂ , C (CH ₃ ) ₂ , (CH ₃ ) ₂ Si, (CH ₃ ) ₂ Ge, (CH ₃ ) ₂ Sn, (C ₆ H ₅ ) ₂ Si,

(C ₆ H ₅ ) (CH ₃ ) Si, (C ₆ H ₅ ) ₂ Ge, (C ₆ H ₅ ) ₂ Sn, (CH ₂ ) ₄ Si, CH ₂ Si (CH ₃ ) ₂ , oC ₆ H ₄ or 2,2 '- (C ₆ H ₄ ) ₂ . Z can also form a mono- or polycyclic ring system with one or more radicals R ¹ and / or R ² .

Exemplary but not limiting examples of metallocene

Catalyst components are:

Bis (cyclopentadienyl) titanium dichloride

Bis (indenyl) titanium dichloride

Bis (fluorenyl) titanium dichloride bis (tetrahydroindenyl) titanium dichloride

Bis (pentamethylcyclopentadienyl) titanium dichloride

Bis (trimethylsilylcyclopentadienyl) titanium dichloride

Bis (trimethoxysilylcyclopentadienyl) titanium dichloride

Bis (isobutylcyclopentadienyl) titanium dichloride bis (3-butenylcyclopentadienyl) titanium dichloride

Bis (methylcyclopentadienyl) titanium dichloride

Bis (1-, 3-di-tert-butylcyclopentadienyl) titanium dichloride

Bis (trifluoromethylcyclopentadienyl) titanium dichloride

Bis (tert-butylcyclopentadienyl) titanium dichloride bis (n-butylcyclopentadienyl) titanium dichloride

Bis (phenylcyclopentadienyl) titanium dichloride

Bis (N, N-dimethylaminomethyl-cyclopentad ienyl) titanium dichloride

Bis (1,3-dimethylcyclopentadienyl) titanium dichloride

Bis (1-methyl-3-n-butylcyclopentadienyl) titanium dichloride (Cyclopentadienyl) (methylcyclopentadienyl) titanium dichloride

(Cyclopentadienyl) (n-butylcyclopentadienyl) titanium dichloride

(Methylcyclopentadienyl) (n-butylcyclopentadienyl) titanium dichloride

(Cyclopentadienyl) (1-methyl-3-n-butylcyclopentadienyl) titanium dichloride

[(Cyclopentadienyldimethylsilyl) (phenyl) amido] titanium dichloride [(Cyciopentadienyldimethylsilyl) (methyl) amido] titanium dichloride [(Cyclopentadienyldimethylsilyl) (tert-butyl) amido] titanium dichloride

[(Cyclopentadienyldimethylsilyl) (cyclohexyl) amido] titanium dichloride

Bis (cyclopentadienyl) zirconium dichloride

Bis (indenyl) zirconium dichloride bis (fluorenyl) zirconium dichloride

Bis (tetrahydroindenyl) zirconium dichloride

Bis (1,3-ditert.butylcyclopentadienyl) zirconium dichloride

Bis (tetramethylcyclopentadienyl) zirconium dichloride

Bis (trimethylsilylcyclopentadienyl) zirconium dichloride bis (trimethoxysilylcyclopentadienyl) zirconium dichloride

Bis (isobutylcyclopentadienyl) zirconium dichloride

Bis (3-butenylcyclopentadienyl) zirconium dichloride

Bis (methylcyclopentadienyl) zirconium dichloride

Bis (trifluoromethylcyclopentadienyl) zirconium dichloride bis (tert.butylcyclopentadienyl) zirconium dichloride

Bis (n-butylcyclopentadienyl) zirconium dichloride

Bis (phenylcyclopentadienyl) zirconium dichloride

Bis (1,3-dimethylcyclopentadienyl) zirconium dichloride

Bis (1-methyl-3-n-butylcyclopentadienyl) zirconium dichloride (Cyclopentadienyl) (methylcyclopentadienyl) zirconium dichloride

(Cyclopentadienyl) (n-butylcyclopentadienyl) zirconium dichloride

(Methylcyclopentadienyl) (n-butylcyclopentadienyl) zirconium dichloride

(Cyclopentadienyl) (1-methyl-3-n-butylcyclopentadienyl) zirconium dichloride

Methylenebis (cyclopentadienyl) zirconium dichloride methylenebis (3-methylcyciopentadienyl) zirconium dichloride

Methylenebis (3-n-butylcyclopentadienyl) zirconium dichloride

Methylenebis (indenyl) zirconium dichloride

Methylenebis (tetrahydroindenyl) zirconium dichloride

Dimethylsilanediylbis (cyclopentadienyl) zirconium dichloride Dimethylsilanediylbis (tetramethylcyclopentadienyl) zirconium dichloride

Dimethylsilanediylbis (2,4,7-trimethylindenyl) zirconium dichloride

Dimethylsilanediylbis (3-methylcyclopentadienyl) zirconium dichloride

Dimethylsilanediylbis (3-n-butylcyclopentadienyl) zirconium dichloride

Dimethylsilanediylbis (indenyl) zirconium dichloride Dimethylsilanediylbis (tetrahydroindenyl) zirconium dichloride Isopropylidenebis (cyclopentadienyl) zirconium dichloride isopropylidenebis (3-trimethylsilylcyclopentadienyl) zirconium dichloride isopropylidenebis (3-methylcyclopentadienyl) zirconium dichloride isopropylidenebis (3-n-butylcyclopentadienylloridiridyldirconium dichloride)

[(Cyclopentadienyldimethylsilyl) (phenyl) amido] zirconium dichloride [(Cyclopentadienyldimethylsilyl) (methyl) amido] zirconium dichloride [(Cyclopentadienyldimethylsilyl) (tert-butyl) amido] zirconium dichloride [(Cyclopentadienyldimethylsilyl) (cyclohexyl) amido] zirconium dichloride 1-silacyclopentane-1,1 -bis (indenyl) zirconium dichloride

1, 6-bis [methylsilylbis (indenyl) zirconium dichloride] hexane 1, 4-disila-1,4-bis [cyclopentadienylzirconium dichloride] cyclohexane 1, 4-disila-1, 4-bis [cyclopentadienyltitanium dichloride] cyclohexane bis (cyclopentadiumdichloride) haf trimethyIsilylcyclopentadienyl) hafnium dichloride

Bis (methylcyclopentadienyl) hafnium dichloride bis (n-butylcyclopentadienyl) hafnium dichloride bis (1-, 3-dimethylcyclopentadienyl) hafnium dichloride methylenebis (cyclopentadienyl) hafnium dichloride methylenebis (3-n-butylcyclidaflium dichloride)

Further examples are the corresponding metallocene compounds in which one or both of the chloride ligands are replaced by bromide, iodide or methyl.

The catalyst composition according to the invention preferably contains one or more activators such as Lewis acids.

Boron compounds such as boranes or aluminum compounds such as aluminum alkyls or aluminoxanes are preferably used as Lewis acid activators. Examples of suitable activators are boranes such as 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, tris (3,4,5-trifluorophenyl) borane or dimethylanilinium [(pentafluorophenyl) borane], IH (OEt ₂ ) ₂ ] [B {3,5- (CF ₃ ) ₂ C ₆ H ₃ } ₄ ], aluminum alkyls such as AI (C ₂ H ₅ ) ₃ , AI (CH ₂ CH (CH ₃ ) ₂ ) ₃ , AI (C ₃ H ₇ ) ₃ , AI ((CH ₂ ) ₃ CH ₃ ) ₃ , AI ((CH ₂ ) ₅ CH ₃ ) ₃ , AI (isoprenyl) ₃ , AI (C ₆ F ₅ ) ₃ , AI ( C ₂ H ₅ ) ₂ CI, Al ₂ (C ₂ H ₅ ) ₃ CI ₃ or AICI ₃ , or aluminoxanes such as methylaluminoxane, isobutylaluminoxane, butylaluminoxane, heptylaluminoxane and methylbutylaluminoxane. Aluminoxanes are particularly preferably used.

The activator can be used in any amount, based on the transition metal components of the catalyst composition according to the invention; it is preferably used in an excess or in stoichiometric amounts. The same activator or different activators can be used to activate the early and late transition metal components of the catalyst composition. The same activator is preferably used for all transition metal components. The activation of the different transition metal components can take place at the same location, e.g. B. in the reactor, or at different locations. In a preferred embodiment, an excess of the activator with the early

Blended transition metal component, and this mixture added to the late transition metal component already contacted with the monomer. An aluminoxane is preferably used as the activator for the catalyst component based on a late transition metal.

An aluminum alkyl is preferably used as the activator for the catalyst component based on an early transition metal in the case of a Ziegler catalyst component and preferably an aluminoxane and / or a borane in the case of a metallocene catalyst component.

The catalyst composition according to the invention optionally contains one or more support components. In this case, both the early and late transition metal components can be supported, or only one of the two components can be supported. In a preferred embodiment variant, both components are supported in order to ensure a relative spatial proximity of the different ones

Ensure catalyst centers and thus ensure good mixing of the different polymers formed.

The carrier component is preferably a porous inorganic or organic solid. The carrier material preferably contains at least one inorganic Halide such as MgCl ₂ or an inorganic oxide such as SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, ThO ₂ , carbonates such as B. Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , sulfates such as Na ₂ SO ₄ , Al ₂ (SO ₄ ) ₃ , BaSO ₄ , nitrates such as e.g. B. KNO ₃ , Mg (NO ₃ ) ₂ , Al (NO ₃ ) ₃ and oxides such as Na ₂ O, K ₂ O, Li ₂ O in particular silicon oxide and / or aluminum oxide or it preferably contains at least one homo- or copolymer, which can be networked, e.g. B. polyethylene, polypropylene, polybutene, polystyrene, cross-linked with divinylbenzene polystyrene, polyvinyl chloride, acrylic-butadiene-styrene copolymer, polyamide, polymethacrylate, polycarbonate, polyester, polyacetal or polyvinyl alcohol. Polymer blends can also be used.

The carrier material can be pretreated, e.g. B. by heating at temperatures from 50 ° C to 1000 ° C, for. B. in an inert gas stream or in vacuo at 0.01 bar to 0.001 bar, or by mixing or reacting with a chemical compound. The chemical compound can react with catalyst poisons such as aluminum, magnesium, boron or lithium alkylene or lead to a functionalization of the surface of the carrier. It is irrelevant whether the carrier material already carries functional groups or whether these are only introduced after the pretreatment by appropriate reactions on the surface.

The support can be made by the individual

Catalyst components are mixed in any order. So z. B. the early and late transition metal compound on the optimally pretreated support (z. B. of SiO ₂ ) are applied and then mixed with the activator, preferably in the presence of monomer.

The present invention relates to a process for the polymerization of ethylene in the presence of the catalyst composition according to the invention. The term polymerization encompasses a conversion to polymers which contain a maximum of 3% by weight of one or more olefinic comonomers, and a homopolymerization of ethylene.

In the event that other comonomers are used in addition to ethylene, the early and late transition metal components can be active for all monomers used, but a transition metal component can also specifically implement only one or more of the monomers used. For example, ethylene and an α-olefin, which preferably has 3 to 20 carbon atoms, can be used. A mixture of two copolymers is obtained, or a mixture of a copolymer with an ethylene homopolymer. The copolymer with the lower α-olefin content is preferably formed by the late transition metal component.

In the processes according to the invention, ethylene is particularly preferably polymerized without the addition of further olefins, a blend of at least two different polyethylenes being obtained. Aliphatic C ₃ -C ₅ hydrocarbons, such as isobutane, are also particularly suitable.

According to the invention, the polymerization process takes place in the liquid phase. This can consist of the monomers used or contain an additional suspension medium. The polymerization is preferably carried out using additional suspension media. Inert organic compounds are preferably used as solvents or suspending agents. Aromatic or aliphatic hydrocarbons or mixtures thereof are particularly preferably used. Toluene, xylenes and saturated aliphatic C ₆ -C ₃₀ hydrocarbons are particularly suitable. The process can also be carried out in supercritical media. The polymerization process is characterized in that the polymeric products form an additional phase during the polymerization. This allows them to be easily separated from the suspension medium after the reaction, for example by filtration or centrifugation.

The polymerization process is carried out in the temperature range from 25 to 150 ° C., particularly preferably 50 to 90 ° C. The process is carried out in the pressure range from 2 to 300 atm, preferably 2 to 100 atm, particularly preferably 3 to 30 atm.

By choosing appropriate reaction conditions, e.g. B. temperature, addition of chain transfer agents such. B. hydrogen, monomer concentrations, and the

Catalyst concentration can be controlled molecular weight distributions, degree of branching and other properties of the polymers formed. The degree of branching of the polymers can be controlled via the concentration of the monomers. The reaction can also take place in two or more reactors connected in cascade. By feeding the catalyst components into the individual Reactors can change the ratio of the two catalysts. The process can be carried out in one or more stages. According to the invention, the conditions are chosen so that the polymeric products form an additional solid phase during the reaction.

The productivity of each individual transition metal component is preferably above 1,000 kg polymer / (mol transition metal x h), particularly preferably above 2,000 kg polymer / (mol transition metal x h).

The polymerization process according to the invention is suitable for the production of

Reactor blends of two or more polymers, which have advantageous application and processing properties. The weight average molecular weights of the individual polymer fractions are preferably in the range from 11 to 10,000 kg / mol, particularly preferably 20 to 1,000 kg / mol. The molar ratio of the proportions of the late transition metal component (s) to the further component (s) can be in the range from 0.1: 99.9 to 99.9: 0.1, preferably 1:30 to 30: 1. The ratio of the proportions of the polymers formed by the late transition metal catalyst and the polymers by the further component (s) can be in the range from 0.1: 99.9 to 99.9: 0.1, preferably 10:90 to 90 : 10, particularly preferably 1: 1 to 1:50.

The polymerization process according to the invention is particularly suitable for the homopolymerization of ethylene into a blend of two or more polymers in a liquid process, these occurring during the polymerization as a suspension in the reaction medium and thus being easy to separate, e.g. by filtration or centrifugation.

The polymerization process according to the invention is particularly preferably suitable for homopolymerizing ethylene to a blend of two or more polymers, at least one of which has the following branching structure:

It contains 2 - 40 branches per 1000 CH ₂ groups, particularly preferably 5 - 15 branches per 1000 CH ₂ groups.

In a further variant of the method according to the invention, essentially linear polymer blends can also be produced, the respective polymers having a different molecular mass. The polymerization process according to the invention is particularly preferably suitable for homopolymerizing ethylene to a blend of two or more polymers which has a density in the range from 0.910 to 0.970 g / ml. In a preferred application, the process is used to produce blends which contain at least 50% by weight, preferably greater than 80% by weight, of a linear ethylene homopolymer with a weight-average molecular weight of at least M _w 200 kg / mol, preferably M _w > 1000 kg / mol included. Linear polyethylenes with molecular weights of M _w > 1000 kg / mol are difficult to process in thermoplastics or cannot be processed at all, so blends of these polymers are also difficult to produce, for example by extrusion processes. In addition to the advantages listed below, the process according to the invention is therefore particularly suitable for producing blends of very high molecular weight polyethylenes which are very difficult to access from the individual components by subsequent blending processes. The presence of branched portions in high molecular weight polyethylenes can improve their application and processing properties.

The production of the polymer blend in the reactor reduces energy consumption, does not require subsequent blend processes and enables simple control of the molecular weight distributions and the like

Molecular weight fractions of the different polymers. In addition, thorough mixing of the polymers can be achieved. The production of a blend of two or more polymers of different degrees of branching from ethylene without the addition of a comonomer reduces the costs of the olefins used, as well as the plant and other costs for providing the comonomer.

The following examples serve to illustrate the invention:

The polymerizations were carried out in a 5L steel autoclave with a heating / cooling jacket and mechanical stirrer. MAO was used as a 10% toluene solution (from Witco). For experiments with supported cocatalyst, silica-fixed MAO-S TA-2794 from Witco was used, Al content 23% by mass. The Exxsol® used as the reaction medium is a mixture of aliphatic hydrocarbons with a boiling range of 100 to 120 ° C. The handling of catalyst precursors and cocatalysts, as well as their solutions or suspensions, was carried out under a protective gas atmosphere. The compounds [{(aryl) -N = C (R) -C (R) = N aryl)} NiBr ₂ ] were developed according to Johnson et al., J. Am. Chem. Soc. 1995, 117, 6414-6415. [{2,6 - {(2,6-Pr ₂ C ₆ H ₃ ) - N = C (Me)} ₂ pyridine} FeCI ₂ ] was carried out according to the method described by Small et al. described methods (9 ^th IUPAC Symposium on Organometallic Chemistry, Göttingen July 20 to 25 1997 Poster 447) synthesized: A solution of 9.15 mmol 2,6-Diisopropyanilin and 6.13 mmol 2,6-diacetyl in 35 mL of methanol was overnight stirred at room temperature. The precipitated product was filtered off, washed with a little methanol and recrystallized from methylene chloride. A solution of 0.38 mmol of the ligand thus obtained in 20 mL methylene chloride was stirred at room temperature overnight with 0.38 mmol of anhydrous iron (II) chloride. The received

The suspension was filtered, the residue washed with pentane and dried in vacuo. [{2,6 - {(2,6-Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} FeCI ₂ ] was obtained as a blue powder.

GPC measurements were carried out on a GPC 210 from PL from polystyrene gel columns from PSS (type SDV, pore size 10 ³ , 10 ⁵ , 10 ⁷ Angstrom). The measurements were carried out at 135 ° C in 1,2,4-trichlorobenzene with universal calibration against linear polyethylene. ¹³ C NMR spectra (75 MHz) were measured at 90 ° C in tetrachloroethane-d ₂ / hexachlorobutadiene with CPD - ¹ H decoupling. MVIs were determined at 190 ° C according to ISO 1133.

The density was determined on pressed plates using the gradient method.

When carrying out polymerizations in a batch process on the scale of the experiments described in the following examples, it is common to work with significantly higher relative amounts of cocatalyst than this in a process on a larger scale, e.g. in continuous operation. The polymers were therefore washed several times after separation from the reaction medium, as shown in the following examples, in order to ensure complete removal of secondary products of the cocatalyst, which e.g. could lead to a distortion of the density measurements. When carried out on a larger scale, with smaller relative amounts of cocatalyst, such a wash is not necessary.

In the experiments listed below, a sample of the filtrate was in each case an excess of methanol after filtration of the reaction solution given. No precipitation of polymer was observed. This proves that the polymeric products in the process used are separated off by filtration.

Examples 1-4 (see Table 1): The autoclave was charged with 3.5 L of solvent, briefly saturated with ethylene under 10 atm, and relaxed to normal pressure. Then, a solution of the early transition metal catalyst component in 10 mL MAO, followed by a solution of the late transition metal catalyst component in 10 mL MAO was added to the autoclave. The autoclave was closed, a constant pressure of 10 atm

Ethylene applied and tempered to 60 ° C. After the specified reaction time, the reaction was stopped by rapidly cooling and venting the ethylene.

The polymer suspension obtained was filtered on a suction filter. The polymer product obtained was treated by stirring with HCl acidic acetone, filtration, stirring twice with acetone and subsequent filtration, and then drying in a vacuum drying cabinet.

Examples 1 and 2 are within the meaning of the invention. Examples 3 and 4 serve for illustration.

Table 2 shows the results of the ¹³ C NMR spectroscopic investigations of the polymers with regard to their branching structure.

Example 5:

The polymerization was carried out analogously to Example 1 (19.4 μmol [{(2.6-

Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6- ⁱ Me ₂ C ₆ H ₃ )} NiBr ₂ ]; 6.4 μmol

[{isopropylidene (fluorenyl) (cyclopentadienyl)} zirconium dichloride]; 45 min reaction time).

136 g of polymer were obtained. The filtrate of the polymer suspension was concentrated on a rotary evaporator at 30 ° C. and 60 mbar and the residue was dried at 20 mbar. 1.1 g of a white solid were obtained. This is insoluble in dilute hydrochloric acid.

This example demonstrates the separation of the polymer from the suspension medium by filtration. Example 6:

The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure. A solution of 1.0 μmol [bis (n-butylcyclopentadienyl)} zirconium dichloride] in 10 mL MAO and a second solution of 15.3 μmol [{(2,6-Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6-

'e ^ _ß H ^ J iBrJ in 10 mL MAO in the autoclave. 30 mmol H _{2 were} added via a lock (partial pressure approx. 0.5 atm), then a constant pressure of 10 atm ethylene was applied and the temperature was raised to 60 ° C. After 55 minutes, the reaction was stopped by rapidly cooling and venting the ethylene. The polymer suspension obtained was filtered on a suction filter. The received

The polymer product was treated by stirring with HCl acid acetone, filtration, stirring twice with acetone and subsequent filtration, and then drying in a vacuum drying cabinet. 74 g of white powder were obtained. Density 0.949 g / mL

MVI (21.6 kg) 30 mL / 10 min.

Example 7 (comparative example):

The polymerization was carried out analogously to Example 6, but with [bis (t7-butylcyclopentadienyl)} zirconium dichloride] / MAO as the sole catalyst component and with the addition of 15 mmol H ₂ .

A polymer with MVI 250 mL / 10 min (21.6 kg), density 0.963 g / mL was obtained.

Example 8 (comparative example):

The polymerization of ethylene was carried out analogously to Example 6, but with

[Bis (n-butylcyclopentadienyl)} zirconium dichloride] as the sole catalyst component and in the absence of hydrogen.

A polymer with MVI 0.1 mL / 10 min (21.6 kg), density 0.938 g / mL was obtained.

Example 9 (comparative example):

The polymerization was carried out analogously to Example 3, but with the addition of

45 mmol H ₂ . The polymer obtained has an MVI of 1 mL / 10 min (21.6 kg), and a molecular weight M _w 163 kg / mol, MJM _n = 3.6. The polymer obtained in Example 3 has a molecular weight of M _w 126 kg / mol, MJM _n = 3.0.

Example 6, in conjunction with Examples 3, 7, 8 and 9, demonstrates the regulation of the catalyst by hydrogen. The early transition metal component is much more sensitive to hydrogen than the late transition metal component and can therefore be controlled selectively

Example 10: The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure. A mixture of 11 μmol [{isopropylidene (fluorenyl) (cyclopentadienyl)} zirconium dichloride], 1.00 g of MAO-S and 10 ml of toluene, and a second mixture of 58.1 μmol [{(2.6- ⁱ Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6- ⁱ Me ₂ C ₆ H ₃ )} NiBr ₂ ], 1.01 g MAO-S and 10 mL toluene were added to the autoclave. The autoclave was closed, a constant one

Pressure of 10 atm ethylene applied and tempered to 60 ° C. After 50 minutes, the reaction was stopped by rapidly cooling and venting the ethylene. The polymer suspension obtained was filtered on a suction filter. The polymer product obtained was treated by stirring with HCl acidic acetone, filtration, stirring twice with acetone and subsequent filtration, and then drying in a vacuum drying cabinet. 72 g of white powder were obtained. This example demonstrates the heterogenization of the catalyst.

Example 11:

The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure. Then a suspension of a Ziegler catalyst (corresponding to 1 mmol titanium) in 10 mL MAO and a second solution of 19.0 μmol [{(2,6- ⁱ Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6- 'Me ₂ C ₆ H ₃ )} NiBr ₂ ] in 10 mL MAO in the autoclave. A constant pressure of 10 atm ethylene was then applied and the temperature was raised to 60.degree. After 45 minutes, the reaction was stopped by rapidly cooling and venting the ethylene.

The polymer suspension obtained was filtered on a suction filter. The polymer product obtained was extracted by stirring with HCl acid acetone, filtration, Stirred twice with acetone and each subsequent filtration and then dried in a vacuum drying cabinet. 114 g of white powder were obtained. Density 0.920 g / mL. MVI (21.6 kg) 0.1 mL / 10 min.

Example 12 (comparative example):

The polymerization of ethylene was carried out analogously to Example 11, but using the Ziegler catalyst as the sole catalyst component. A polymer was obtained whose MVI cannot be measured due to the low flowability.

Examples 11 and 12 demonstrate the production of reactor blends with a high molecular weight linear polyethylene component.

Example 13:

The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure. Then a solution of 5.0 μmol [{2,6 - {(2,6-Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} FeCI ₂ ] in 10 mL MAO, as well as a second solution of 0.5 μmol [bis (n-butylcyclopentadienyl)} zirconium dichloride] in 10 L MAO in the autoclave. The autoclave was closed, a constant pressure of 10 atm ethylene was applied and the temperature was raised to 60 ° C. After 35 minutes the reaction was stopped by rapidly cooling and venting the ethylene. The polymer suspension obtained was filtered on a suction filter. The received

Polymer product was treated by stirring twice with acetone and subsequent filtration and then dried in a vacuum drying cabinet. 184 g of white powder were obtained. Density 0.961 g / mL MVI (21.6 kg): 10 mL / 10 min

Example 14 (comparative example):

The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure. A solution of 7.8 μmol [{2,6 - {(2,6-Pr ₂ C ₆ H ₃ ) -N = C (Me)} ₂ pyridine} FeCI ₂ ] in 10 mL MAO was then added to the Given autoclaves. The autoclave was closed, a constant pressure of 10 atm ethylene was applied and the temperature was raised to 70 ° C. After 55 minutes, the reaction was stopped by rapidly cooling and venting the ethylene. The polymer suspension obtained was filtered on a suction filter. The polymer product obtained was extracted by stirring and subsequent filtration

HCl-acidic methanol, water, methanol and acetone treated and then dried in a vacuum drying cabinet. 80 g of white powder were obtained. Density 0.968 g / mL MVI (21.6 kg): 170 mlJ10 min ¹³ C NMR spectroscopy one under the same conditions in toluene as

The polymer obtained from the suspending agent shows that it is a linear polyethylene

Example 15 The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure.

A solution of 3.0 μmol [bis (π-butylcyclopentadienyl)} zirconium dichloride] in 10 mL toluene and a solution of 58.3 μmol [{(2,6- ⁱ Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6- 'MeaC _ß H ^ NiBrJ in 10 mL toluene were combined and then added to 2.00 g of MAO-S. The mixture was stirred briefly and then added to the autoclave. The autoclave was closed, a constant pressure of 10 atm of ethylene was applied and the temperature was raised to 60 ° C. After 45 minutes, the reaction was stopped by rapidly cooling and draining the ethylene, and the polymer suspension obtained was filtered on a suction filter, and the polymer product obtained was stirred with methanol, filtered off and then in one

Vacuum drying cabinet dried. 32 g of white powder were obtained. This example demonstrates the heterogenization of the catalyst.

Example 16

The autoclave was charged with 3.5 L of Exxsol, saturated with ethylene by briefly stirring under 10 atm, and depressurized to normal pressure.

A solution of 3.0 μmol [bis (n-butylcyclopentadienyl)} zirconium dichloride] in 2 mL

MAO (30% in toluene) and a solution of 58.1 μmol [{(2,6-'Me ₂ C _β H ₃ ) - N = C (Me) -C (Me) = N- (2,6- ⁱ Me ₂ C ₆ H ₃ )} NiBr ₂ ] in in 2 mL MAO (30% in toluene) combined and then added to 2.00 g of silica (Grace 948, 24 hours at 140 ° C and 10 mbar). The mixture was shaken briefly, the solvent was removed in vacuo and the residue was dried for 20 minutes in an oil pump vacuum at room temperature for 20 minutes. The solid obtained in this way was suspended in 20 ml of Exxsol and the suspension was added to the autoclave. The autoclave was closed, a constant pressure of 10 atm ethylene was applied and the temperature was raised to 60 ° C. After 50 minutes, the reaction was stopped by rapidly cooling and venting the ethylene.

The polymer suspension obtained was filtered on a suction filter. The polymer product obtained was stirred with methanol, filtered off and then in one

Vacuum drying cabinet dried. 295 g of white powder were obtained. This example demonstrates the heterogenization of the catalyst.

Table 1.

Example catalyst components n (1) / n (2) / reaction yield delta. / Density MVI (21.6 kg)

No. μmol μmol time polymer / g 1000 CH ₂ g / mL mL / 10 min

1 A / B 28.8 12.4 30 min 193 11 ^a) 0.932 2

2 A / B 27.8 3.9 30 min 125 23 ^a) 0.918 14

3 A 28.6 - 56 min 102 29 a) 0.910 10

4 B - 8.7 53 min 107 <2 0.953 4

A = [{(2,6-Me ₂ C ₆ H ₃ ) -N = C (Me) -C (Me) = N- (2,6-Me ₂ C ₆ H ₃ )} NiBr ₂ ] B = [ {isopropylidene (fluorenyl) (cyclopentadienyl)} zirconium dichloride] r

Temperature: 60 ° C; Pressure: 10 atm ethylene; Reaction medium: toluene (Example 3: Exxsol); Cocatalyst: MAO.

a) determined by ¹³ C NMR

Table 2. Branching structure of the polymers

Example - total branches / branches / 1000 CH ₂

No. 1000 CH ₂

Methyl ethyl n-butyl long chain ^a)

1 10.6 7.4 1.1 0.4 17

2 22.8 16.3 1.6 1.6 3.3

3 28.7 20.4 1.8 1.0 5.5

Determined by ¹³ C NMR. a) Hexyl branches or higher.

Claims

Claims:

1. Suspension polymerization process for the production of polyethylene by polymerizing ethylene in the presence of a catalyst composition containing

A) at least one polymerization catalyst based on a late transition metal component, which produces a polyethylene with a degree of branching of 0-40 branches per 1000 methylene groups and

B) at least one further polymerization catalyst based on an early or late transition metal, and the polymerization is carried out in the presence of a medium which is liquid under the reaction conditions and under elevated pressure, and the resulting polymer is separated from the liquid suspension medium without the addition of precipitants.

2. The method according to claim 1, characterized in that a polymerization catalyst based on a late transition metal component is used which produces a polyethylene with a degree of branching of 2-35 branches per 1000 methylene groups.

3. The method according to claim 1 or 2, characterized in that an early transition metal component based on a metal from the groups purple to Vlla, and the group of lanthanoids of the periodic table of the elements is used as the polymerization catalyst.

4. The method according to claim 1 or 2, characterized in that a late transition metal component based on a metal of the groups IB and Villa of the periodic table of the elements is used as the polymerization catalyst.

5. The method according to claim 4, characterized in that a late transition metal component based on a nickel, palladium, platinum, iron, ruthenium, cobalt or rhodium compound is used as the polymerization catalyst.

6. The method according to claim 5, characterized in that a late transition metal component based on a nickel, palladium or iron compound is used as the polymerization catalyst.

7. The method according to claim 4, characterized in that as the polymerization catalyst, a late transition metal component containing a ligand of the formulas II and / or III

R7

(") (III) wherein

R ⁷ , R ^{8 are} independently the same or different

hydrogen radicals, in which preferably the carbon atom bonded to the nitrogen atom is connected to at least two further carbon atoms, R ⁹ , R ^10, independently of one another, the same or different, mean a hydrogen atom or a C 1-4 hydrocarbon radical or R ⁹ and R ¹⁰ together form a ring system.

8. The method according to claim 3, characterized in that an early transition metal component based on a Ziegler catalyst and / or a metallocene catalyst is used as the polymerization catalyst.

9. The method according to claim 8, characterized in that a Ziegler catalyst based on a metal of IVa, Va and / or Via group of the periodic table is used.

10. The method according to claim 8, characterized in that an unbridged or bridged metallocene of formula I as the metallocene catalyst

wherein

M is a metal from the group purple, IVa, Va or Via of the Periodic Table of the Elements, R ^{1 are the} same or different and are a hydrogen atom or SiR ₃ ³ , wherein R ^{3 is the} same or different a hydrogen atom or a C _r C ₄₀ - carbon-containing group, or R ^{1 is} a C _r C ₃₀ - carbon-containing group, or two or more radicals R ¹ can be connected to one another in such a way that the radicals R ¹ and the atoms of the cyclopentadienyl ring connecting them form a C ₄ -C ₂₄ ring system, which in turn can be substituted

I is 5 for v = 0 and I is 4 for v = 1,

Y either a) an element of V. (e.g. nitrogen or phosphorus) or VI. (e.g. oxygen or sulfur) main group of the periodic table of the

Is element bearing one or two CC ₂₀ hydrocarbon substituents, or

b) a residue of the formula

is what

R ^{2 are the} same or different and are a hydrogen atom or

Are SiR ₃ ³ , in which R ^3, identical or different, represents a hydrogen atom or a C _r C ₄₀ carbon-containing group, or R ^{2 is} a CC ₃₀ - carbon-containing group, or two or more radicals R ² can be linked to one another in such a way that the radicals R ² and the atoms of the cyclopentadienyl ring connecting them form a C ₄ -C ₂₄ ring system, which in turn can be substituted , and m is 5 for v = 0, and m is 4 for v = 1, L ^{1 can be the} same or different and a hydrogen atom, a CC ₂₀ hydrocarbon radical, a halogen atom, or OR ⁶ , SR ⁶ , OSiR ₃ ⁶ , SiR ₃ ⁶ , PR ₂ ⁶ or NR ₂ ⁶ , wherein R ^{6 is} a halogen atom, a C, -C ₁₀ alkyl group, a halogenated C ^ C ^ alkyl group, a C ₆ -C ₂₀ aryl group or a halogenated C ₆ -C ₂₀ aryl group, or L ¹ is a toluenesulfonyl, trifluoroacetyl, trifluoroacetoxyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl or 2,2,2-trifluoroethanesulfonyl group, o is an integer from 1 to 4, Z is a bridging structural element between the two

Designated cyclopentadienyl rings and v is 0 or 1, is used.

11. The method according to claim 1, characterized in that the catalyst composition additionally contains one or more activators.

12. The method according to claim 1, characterized in that the catalyst composition additionally contains a carrier.

13. The method according to claim 1, characterized in that the polymerization is carried out in the temperature range from 25 to 150 ° C.

14. The method according to claim 1, characterized in that the polymerization is carried out in the pressure range from 2 to 300 atm.

15. The method according to claim 1, characterized in that the polymerization is carried out in the presence of saturated aliphatic and / or aromatic hydrocarbons as the suspension medium.