EP1237952A1

EP1237952A1 - Method for the homogeneous catalytic production of highly branched amorphous polyolefins

Info

Publication number: EP1237952A1
Application number: EP00983173A
Authority: EP
Inventors: Johannes Heinemann; Rolf Mülhaupt; Joachim Queisser; Gerrit Luinstra; Michael GEPRÄGS
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1999-12-13
Filing date: 2000-11-27
Publication date: 2002-09-11
Also published as: WO2001044317A1; JP2003517056A; DE19960123A1

Abstract

The invention relates to a method for the homogeneous catalytic production, starting from ethene, of highly branched amorphous polyolefins which have an elastomeric characteristic profile. In a first step of said method a) ethene is oligomerized in the presence of a transition metal compound of general formula (I), whereby R<1> and R<2> represent C4 to C16 heteroaryl or C6 to C16 aryl with hydrogen substituents in both vicinal or ortho positions in relation to the binding site between the aryl or heteroaryl and N<a> or N<b> and is optionally oligomerized in the presence of a co-catalyst in an inert solvent. In a further step b), a transition metal compound of general formula (II) is added to the oligomerization mixture produced according to step a) and the reaction is continued in the presence of ethene. In a subsequent step c), the polymer product obtained is isolated.

Description

Process for the homogeneous catalytic production of highly branched amorphous polyolefins

description

The present invention relates to a process for the homogeneous catalytic preparation of highly branched amorphous polyolefins with an elastomeric property profile based on ethene.

It is known to the person skilled in the art to admix highly branched polyolefins, provided they are sufficiently amorphous, as an elastomeric component, polymer mixtures and single polymers for the purpose of toughening (see also Kunststoffe, 1999, 89, 154-162). Highly branched polyolefins generally consist of a polyethylene backbone with, as a rule, statistically distributed alkyl side branches of different lengths. Unlike e.g. Polybutadiene rubbers usually have highly branched polyolefins with no double bond units and are therefore little or not sensitive to the effects of the weather.

Different approaches have been developed for the production of branched polyolefins. According to a regulation described in US Pat. No. 5,272,236, 1-alkenes such as 1-hexene or 1-octene can be in the presence of

[(η ⁵ -C ₅ Me) SiMe ₂ (η ¹ -NCMe ₃ )] copolymerize TiCl ₂ as a catalyst with ethene to give branched polyethylene. This variant always requires the upstream, separate production of 1-olefins.

Beach and Kissin, Polym. Sei., 1984, 22, 3027, combine two Ziegler-Natta catalysts to produce branched polyolefins based on ethene. By means of a catalyst mixture of titanium alkoxides and triethylaluminum, 1-butene is first of all generated, which is copoly erated with ethene in the presence of titanium tetrachloride supported on magnesium chloride and triethylaluminum. With 20 alkyl branches per 1000 carbon atoms, however, the branching rate is too low to provide sufficient amorphous material. In addition, the low yields of using this method do not only stand in the way of an industrial scale.

According to a regulation by Barnhart and Bazan, J. Am. Chem. Soc, 1998, 120, 1082-1083, branched polyolefins can also be obtained from ethene if two metallocene complexes are combined with one another. However, this is only possible if the polymerization activity of the transition metal compounds used towards ethene is very well coordinated, because otherwise either no polyolefin backbone or no 1-alkenes to be polymerized are formed. According to Barnhart and Bazan, care must also be taken to ensure that the transition metal compounds used do not give dimeric coupling products from the 5 1-alkenes produced, which would lead to inhomogeneous product mixtures. In addition, the two metallocene compounds, which are different in their reactivity, must not have any chemical interaction with one another. These diverse requirements for the production of branched polyolefins from ethene

According to Barnhart and Bazan, 10 only does justice to a well-defined zirconocene complex that is complexed with two boratobenzene rings, with the free valence on the boron atom being saturated with one ethoxy group. Already the exchange of the ethoxy group for a phenyl group no longer leads to the desired branched

15 polyolefins.

Brookhart et al., J. Am. Chem. Soc. 1995, 117, 6414-6415, starting from ethene using a nickel diimine catalyst also lead to branched polyethylene. In the alkyl process

20 branches, however, are predominantly methyl groups, which is why the elastomeric property profile of the polyolefins obtained is not very pronounced. With corresponding palladium complexes, highly branched amorphous polyolefins are obtained starting from ethene, but they are

25 Productivities so low that a technical application is out of the question.

The combined use of olefin polymerization catalysts leads to Ahn et al. , Polymer Engineering and Science,

30 1999, 39, 1257-1264, on polyethylene with a bimodal particle size distribution or on polyethylene with a very broad molecular weight distribution. The authors initially used ethene with a metallocene compound, e.g. with bis (cyclopentadienyl) zirconium dichloride or bis (indenyl) zirconium dichloride, where

35 the reactivity of the catalyst used by adding

Triethyl aluminum had to be reduced, and then the reaction after the addition of a Ziegler / Natta compound, e.g. Titanium tetrachloride vanadium oxide trichloride, continued.

40 The synthesis of polyolefin blends based on ethene

The use of a catalyst composition consisting of a polymerization catalyst based on an early transition metal compound and a polymerization catalyst based on a late transition metal compound is described in DE-A 197 07 236. Ziegler / Natta catalysts, for example based on titanium tetrachloride or metallocene catalysts, are used as early transition metal compounds based on titanium, zirconium or hafnium cyclopentadienyl complexes, used as late transition metal compounds, for example diimine complexes of nickel or palladium. The polymer blends obtained contain linear or only slightly branched polyethylene in addition to branched polyethylene.

Fink et al., Macromol. Chem. Rapid Commun. , 1991, 12, 697-701, have combined nickel-ylide complexes with bridged and unbridged metallocene complexes to produce branched polyethylene based on ethene. However, the proportion of incorporated α-olefin is regularly very low. In addition, acceptable activities are obtained only through large amounts of methylalumoxane as cocatalyst, with an increased tendency to dimerization being accepted.

EP-A 0 250 999 discloses the combined use of a nickel-ylide complex as an oligomerization catalyst with a heterogeneous chromium polymerization catalyst supported on silica gel for the production of branched polyolefins starting from ethene. In this way, however, only polyolefins with very long alkyl branches are obtained, which is why materials with a partially crystalline or crystalline, but not with an amorphous property profile are obtained.

WO 99/10391 describes simultaneous and sequential

Use of different polymerization catalysts described. However, even with sterically demanding nickel diimine complexes and bis (cyclopentadienyl) zirconocene dichloride complexes, only partially crystalline materials can be obtained.

According to WO 99/50318, for the production of branched polyolefins from, for example, ethylenetridentate, iron bisimine complex compounds and metallocene catalysts are added to the reaction mixture either simultaneously or sequentially. However, branched polyolefins with sufficiently high alkyl branching rates and suitable alkyl branching patterns, which likewise have a sufficiently elastomeric property profile, can not be reproducibly achieved by the process described, in order to be able to be used as toughness modifiers. This is already contradicted by the thermal properties of the polymers described, which have melting points T _m > 100 ° C. In addition, the α-olefins formed cannot be reliably incorporated into the copolymer chain by the process described, which is why these compounds remain as residues in the copolymer and contaminate it and, if necessary, have to be separated in a complicated manner by additional purification steps. For the production of highly branched polyolefins starting from ethene, it would be desirable to be able to use two or more component catalyst systems which are easy to handle, show high activity and lead to high branching rates and thus to amorphous elastomeric products. The present invention was therefore based on the object of making available a process with which amorphous or largely amorphous elastomeric polyolefins can be obtained in a preparative, simple and efficient manner, even on an industrial scale, in a satisfactory manner.

Accordingly, a process for the homogeneous catalytic production of highly branched polyolefins with an elastomeric property profile was found, in which in a first step

a) ethene in the presence of at least one transition metal compound of the general formula (I)

in which the substituents and indices have the following meaning:

R! , R ² C - to Ci ₆ ~ heteroaryl or C ₆ - to -C ₆ aryl mi t

Hydrogen f substituents in the two vicinal positions to the junction between the aryl and. Heteroaryl and N ^a resp. N ^b ,

R ³ , R ⁴ hydrogen f, Ci to C ₁₀ alkyl, C ₃ to C ₁₀ cycloalkyl, C ₆ to C ₆ aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) _{3 with}

R ^{8 is} Ci- to Cio-alkyl, C ₃ - to -CC ₀ cycloalkyl, C ₆ - to -CC ₆ aryl, alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part, R ⁵ , R ⁶ , R ^{7 are} hydrogen, Ci- to Cι ₀ -alkyl, C- to Cio-cycloalkyl, C ₆ - to C ₁₆ -aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁵ and R ⁶ and / or R ⁶ and R ⁷ together form a fused five -, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M ¹ Fe, Ru, Co, Rh, Ni or Pd

T, Q neutral or monoanionic monodentate ligands or T and Q together form a diketoenolate unit or a C ₂ or C ₃ alkylene unit with a methyl ketone or a linear C 1 -C 4 -alkyl ester or nitrile end group,

A a non or poorly coordinating anion,

m, p 0, 1, 2 or 3,

q 1, 2 or 3 and

n 1, 2 or 3

and optionally one or more cocatalysts in the form of strong neutral Lewis acids, ionic compounds with a Lewis acidic cation or ionic compounds with a Bronsted acid as a cation oligomerized in an inert solvent in a further step

b) at least one transition metal compound of the general formula (II)

_R 10

in which the substituents and indices have the following meaning:

R ⁹ to R ^{12 are} hydrogen, C 1 to C 10 alkyl, C ₃ to C ₀ cycloalkyl, C ₆ to C ₆ aryl, alkylaryl having 1 to 10

C atoms in the alkyl and 6 to 14 C atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁹ and R ¹⁰ and / or R ¹¹ and R ¹² together form an anellated five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M ^{11 is} a metal from group IIIB, IVB, VB or VIB of the Periodic Table of the Elements,

T ', Q' is a hydrogen atom, a Ci to Cι ₀ alkyl or

C _{6 to} C Q aryl, a halogen atom, -OR ', -SR', -0SiR ' ₃ , -SiR' _{3 #} -CR " ₂ SiR ' ₃ , -PR' ₂ , -NR ' ₂ toluenesulfonyl , Trifluoroacetyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl, 2,2,2-trifluoroethanesulfonyl,

Z -CR ' ₂ -, -SiR' ₂ -, - GeR ' ₂ -, -SnR' ₂ -, -BR'- or- -0- with

R 'Ci to C ₂₀ alkyl, C ₃ to C ₀ cycloalkyl, C ₆ to C bis ₆ aryl, alkylaryl having 1 to 10 C atoms in the alkyl and 6 to 10 C atoms in the aryl part,

Ci to C ₂ o ~ alkoxy, C to -C ₀ cycloalkoxy,

C ₆ - to Ci ₆ ~ aryloxy or alkylaryloxy with

1 to 10 carbon atoms in the alkyl and 6 to 10 carbon atoms in the aryl part,

1, 2 or 3,

G -0-, -S-, -NR '', -PR '', -BR '' -, -OR '' -, -SR '' -, -NR '' ₂ , -PR '^# ₂ or a Rest of formula (III)

in which the substituents R ⁹ to R ^{12 have} the abovementioned meaning,

R '' hydrogen, -C ~ to C ₂ o-alkyl, C ₃ - to Cι ₀ cycloalkyl, C ₆ - to Cι ₅ aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 10 C. -Atoms in the aryl part or C ₃ - to C ₃₀ organosilyl, or

Z _k and G together form a substituted or unsubstituted aromatic or heteroaromatic structure from 4 to 16 ring carbon atoms or

Z _k and R ⁹ and / or R ¹² together form a mono- or polycyclic aliphatic, aromatic or heteroaromatic ring system,

and optionally further cocatalysts, as described under step a), are added to the oligomerization mixture according to a) and the reaction is continued in the presence of ethene and then the polymer product obtained is isolated in step c).

The radicals R ¹ and R ² in the compound (I) represent C - to Cχ ₆ heteroaryl or C ₆ - to Ci ₆ aryl groups, each in their two vicinal (ortho) positions to the point of attachment between the imine nitrogen atom N. ^a or N ^b and the aryl or heteroaryl radical, ie for example in the case of one

Phenylrestes ortho-constantly substituted for the covalent bond between the phenyl radical and the imine nitrogen with hydrogen atoms.

The substituents R ¹ or R ² in a compound (I) can match or differ from one another in terms of their aromatic or heteroaromatic ring system and / or further substituents present in the non-vicinal position. The heteroaryl or aryl radicals R ¹ and R ² can have one or more substituents in addition to the two vicinal or ortho hydrogen atoms described. Examples of such substituents are functional groups based on the elements from groups IVA, VA, VIA or VIIA of the Periodic Table of the Elements. Suitable are, for example, linear or branched Ci to Cio alkyl, preferably C ₁ -C ₆ alkyl such as methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, partially or perhalogenated Ci to Cio-alkyl, preferably C ~ ~ to C ₆ alkyl such as trifluoro or trichloromethyl or 2, 2, 2-trifluoroethyl, triorganosilyl such as trimethyl, triethyl, tri-t-butyl, triphenyl or t-butyldiphenylsilyl, the Nitro, cyano or sulfonato group, amino, for example NH ₂ , dimethylamino, di-i-propylamino, di-n-butylamino, diphenylamino or dibenzylamino, C 1 ~ to C ₁ -alkoxy, preferably C 1 ~ to C ₆ - Alkoxy such as methoxy, ethoxy, i-propoxy or t-butoxy, or halogen such as fluoride, chloride, bromide or iodide.

Preferred among the aryl radicals R ¹ , R ² are the phenyl,

Naphthyl and anthracenyl group. Phenyl and naphthyl groups are particularly preferred and the phenyl group is particularly preferred, these aryl radicals also each having the aforementioned further substituents in the positions which are not vicinal or. are ortho-permanent, can wear.

Particularly suitable among the aforementioned phenyl radicals are those which, in the para position to the attachment position to the imine nitrogen, contain a hydrogen atom or a methyl, i-propyl # t-butyl, trichloromethyl, trifluoromethyl, methoxy,

Have ethoxy, chlorine or bromine. Particularly preferred radicals R ¹ , R ² are, for example, 4-i-propylphenyl, 4-methylphenyl, 4-methoxyphenyl or phenyl.

The C - to C ₆ heteroaryl radicals R ¹ and R ² in question for the purposes of the present invention are to be understood as meaning substituted or unsubstituted heteroaryl radicals insofar as they have hydrogen atoms in their two vicinal positions to the point of attachment to the imine nitrogen. Preferred are C - to Cg-heteroaryl radicals such as the pyrrolidyl (linked to the imine nitrogen via a ring carbon atom) or the pyrrolidine group (linked to the imine nitrogen via the pyrrole nitrogen) or the imidazolyl (CN-linked), imidazolid (NN- linked), benzimidazolyl, benzimidazolid, pyrazolyl, pyrazolid, pyridinyl,

Pyrimidinyl, quinolyl or the isoquinolyl group. Under of these, the pyrrolidyl and, in particular, the pyrrolide radical are to be emphasized.

The radicals ³ and R ⁴ in (I) are hydrogen, Cχ ~ to Cio-alkyl, C ₃ - to Cio-cycloalkyl, C ₆ - to Cχ ₆ -aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 up to 14 carbon atoms in the aryl part, silyl (Si (R ⁸ ) ₃ ), amino (N (R ⁸ ) ₂ ), ether (OR ⁸ ) or a thioether residue (SR ⁸ ) in question. The radicals R ³ and R ⁴ include hydrogen, methyl, ethyl, i-propyl, t-butyl, methoxy, ethoxy, i-propoxy, t-butoxy, trifluoromethyl, phenyl,

Naphthyl, tolyl, 2-i-propylphenyl, 2-t-butylphenyl, 2,6-di-i-propylphenyl, 2-trifluoromethylphenyl, 4-methoxyphenyl, pyridyl or benzyl and especially hydrogen, methyl, ethyl, i-propyl or t -Butyl preferred. Ligand compounds with these residues can be found in K. Vrieze and G. van Koten, Adv. Organomet. Chem., 1982, 21, 151-239, and J. Matei, T. Lixandru, Bul. Inst. Politeh. Isai, 1967, 13, 245. Furthermore, preferred heterocyclic systems R ³ , R ⁴ 1, 4-dithiane, as described in WO 98/37110.

The radicals R ⁵ , R ⁶ and R ^{7 are} independently hydrogen, Ci- to Cio-alkyl, C ₃ - to C ₁₀ cycloalkyl, C ₆ - to -C ₆ -aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl - And 6 to 14 carbon atoms an aryl part or a silyl radical (Si (R ⁸ ) ₃ ) or a functional group based on the elements of the groups VA to VIIA of the periodic table of the elements. Suitable functional groups are, for example, amino, such as NH ₂ , dimethylamino, di-i-propylamino, di-n-butylamino, diphenylamino or dibenzylamino, C 1 ~ to C ₁ -alkoxy, preferably C ₁ -C ₆ -alkoxy, for example methoxy , Ethoxy, n- or i-propoxy, n-, i- or t-butoxy, or halogen such as fluoride, chloride, bromide or iodide.

R ⁵ and R ⁶ or / and R ⁶ and R ⁷ can also, together with the pyridyl system, form a fused five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle, for example a substituted one or unsubstituted isoquinoline system.

The radicals R ⁵ , R ⁶ and R ⁷ are preferably hydrogen or methyl, in particular hydrogen.

The R ⁸ radicals are C ₁ -C 10 -alkyl, preferably C 1 -C ₆ -alkyl, C ₆ - to C ₆ -aryl, preferably C ₆ -C ₁ -aryl, or alkylaryl with 1 to 10, preferably 1 to 6 C atoms in the alkyl and 6 to 14, preferably 6 to 10 C atoms in the aryl part in Question. Suitable residues are, for example, triorganosilyl residues such as trimethyl, triethyl, triphenyl or t-butyl-diphenylsilyl.

Unless expressly described otherwise elsewhere, the alkyl, cycloalkyl, aryl and alkyl aryl groups of the radicals R ³ to R ⁸ include the following substituents:

Cχ ~ to Cio-alkyl radicals preferably include, for example, the methyl, ethyl, n- or i-propyl, n-, i- or t-butyl group and the pentyl, hexyl or heptyl group in straight-chain and branched form. C 1 to CiQ alkyl radicals also include those which are substituted with functional groups based on the elements of groups IVA, VA, VIA or VIIA of the periodic table, for example partially or perhalogenated alkyl radicals such as trichloromethyl, trifluoromethyl,

2, 2, 2-trifluoroethyl, pentafluoroethyl or pentachloroethyl as well as one or more alkyl radicals carrying epoxy groups, for example propenoxy. Among the C ₁ -C 8 -alkyl radicals, the C ₁ -C ₆ -alkyl radicals are regularly preferred.

Suitable C ₃ - to Cio-cycloalkyl radicals include carbocycles and heterocycles, for example substituted and unsubstituted cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, pyrrolyl, pyrrolidonyl or piperidinyl. Examples of substituted cycloaliphatic radicals include 1-methylcyclohexyl, 4-t-butylcyclohexyl and 2,3-dimethylcyclopropyl.

Suitable C ₆ -C ₅ aryl groups generally include substituted and unsubstituted aryl radicals. Among the unsubstituted aryl radicals, the C ₆ -C ₁ -aryl groups such as phenyl and naphthyl are preferred. Phenyl is particularly preferred. In the unsubstituted as well as the substituted C ₆ - to Ci ₆ aryl groups, the indication of the carbon atoms (for example Cξ, Cι ₀ - or Cι ₆ -) indicates the number of carbon atoms which form the aromatic system (with) , Carbon atoms from possible alkyl and / or aryl substituents are not yet covered by this information. The statement Cς to Cχ ₆ aryl thus also includes, for example, substituted C ₆ to C ₆ aryl radicals such as substituted

Anthracenyl. C ₆ to C ₆ aryl radicals accordingly also include those radicals which are single, multiple or persubstituted with functional groups based on the elements from groups IVA, VA, VIA and VIIA of the Periodic Table of the Elements. Suitable functional groups are Cι ~ to Cio-alkyl, preferably Cι ~ to C ₆ alkyl, C ₆ - to C _ß -aryl, preferably C ₆ - to Cio-aryl, triorganosilyl such as trimethyl-, triethyl-, Triphenyl- or t-butyl-diphenylsilyl and amino, for example NH ₂ , dimethylamino, di-i-propylamino, di-n-butylamino, diphenylamino or dibenzylamino, Cι ~ to Cio-alkoxy, preferably Cι ~ to C ₆ -alkoxy, for Example methoxy, ethoxy, n- or i-propoxy, n-, i- or t-butoxy, or halogen such as fluoride, chloride, bromide or iodide.

C ₆ to C ₆ aryl radicals are also to be understood as substituted and unsubstituted heteroaryl radicals with respect to the substituents R ³ to R ⁸ , for example C - bis

Cι ₃ heteroaryl, preferably C ₄ - to Cg heteroaryl, such as pyridyl, pyrimidyl, quinolyl or isoquinolyl.

Suitable alkylaryl radicals R ³ to R ⁸ generally include 1 to 10, preferably 1 to 6, carbon atoms in the alkyl and 6 to 14, preferably 6 to 10, carbon atoms in the aryl part, in particular the benzyl group.

The metals M ¹ in (I) are the elements iron, cobalt, ruthenium, rhodium, palladium or nickel. In the transition metal compounds (I), iron, cobalt, ruthenium, palladium and nickel are generally formally charged twice or three times positively, and rhodium generally has a single or triple positive charge. Cobalt and iron are preferred among the metals M ¹ , and iron is particularly preferred.

In one embodiment, T and Q represent neutral and / or monoanionic monodentate ligands. Lewis bases are suitable as neutral ligands, for example acetonitrile, benzonitrile, diethyl ether, tetrahydrofuran, amines, ketones, phosphines, ethyl acetate, dimethyl sulfoxide, dimethylformamide or hexamethylphosphoric triamide. Also suitable as a Lewis basic neutral ligand is ethene or an olefinically unsaturated compound in general. Monoanionic ligands are, for example, carbanions based on substituted or unsubstituted alkyl, aryl or acyl radicals or halide ions.

T in (I) preferably denotes a monoanionic radical such as

Sulfonate, borate, chloride, bromide or iodide, methyl, phenyl, benzyl or a Cι ~ to Cio-alkyl, which has no hydrogen atoms in the β-position to the metal center M ¹ . This also includes those radicals which have a C 1 -C 8 -alkyl ester or a nitrile end group. Are particularly preferred Chloride and bromide as halides or trifluoromethyl sulfonate as sulfonate and methyl as the alkyl radical.

The rest Q, like T, preferably represents trifluoromethyl sulfonate, chloride, bromide, iodide, methyl, phenyl, benzyl or a C 1 -C 1 -alkyl which has no hydrogen atoms in the β position to the metal center M ¹ and has a C ¹ -C ₄ - Q is preferably acetonitrile, benzonitrile, ethene, triphenylphosphine as monodentate phosphorus compound, pyridine as monodentate aromatic nitrogen compound, acetate, propionate or butyrate, especially acetate as a suitable carboxylate, a linear alkyl ether, for example one linear di-C ₂ - to C ₆ -alkyl ethers such as diethyl ether or di-i-propyl ether, preferably diethyl ether, a cyclic alkyl ether such as tetrahydrofuran or dioxane, preferably tetrahydrofuran, a linear C 1 -C 4 -alkyl ester, for example ethyl acetate, Dimethyl sulfoxide, dimethylformamide, hexamethylphosphoric triamide or a halide. In the case of iron complexes (I) (M ¹ = Fe), Q is preferably an H alogenide, for example a chloride or bromide, in the case of cobalt complexes (M ¹ = Co), Q is preferably chloride.

Furthermore, the radicals T and Q together can represent a C ₂ - or C ₃ -alkylene unit with a methyl ketone, a linear C 1 -C 4 -alkyl ester or a nitrile end group or a dicetoenolate, for example acetylacetonate. T and Q here preferably represent a —CH ₂ CH ₂ CH ₂ C (0) OCH ₃ unit and in this way form a six-membered cycle together with M ¹ . While the terminal methylene unit forms a metal / carbon bond with M ¹ , the carbonyl group coordinates with M ¹ .

A non-coordinating or poorly coordinating anion A is to be understood according to the invention to mean those anions whose charge density at the anionic center is reduced due to electronegative residues and / or whose residues sterically shield the anionic center. Suitable anions A include antimonates, sulfates, sulfonates, borates, phosphates or perchlorates, for example B [C ₆ H ₃ (CF ₃ ) ₂ ] ₄ ^~ (tetrakis (3, 5-bis- (trifluoromethylphenyldborate), B [C ₆ F ₅ ] ₄ -, BF ₄ ^_ , SbF ₆ ", A1F ₄ -, AsF ₆ -, PF ₆ ^~ or trifluoroacetate (CF ₃ S0 ₃ ^_ ). Preferred are B [C ₆ H ₃ (CF ₃ ) ₂ ] ₄ " , SbF ₆ ^_ and PF ₆ ^_ . Borates, in particular B [C ₆ H ₃ (CF ₃ ) ₂ ] ₄ ", are particularly preferred. Suitable non or poorly coordinating anions A and their preparation are described, for example, by SH Strauss , Chem. Rev. 1993, 93, p. 927 - 942, as well as in W. Beck and K. Sünkel, Chem. Rev. 1988, 88, pp. 1405-1421.

Preferred transition metal compounds (I) are, for example: 2,6-bis [1- (phenylimino) ethyl] pyridine-iron (II) chloride,

2,6-bis [1- (4-methylphenylimino) ethyl] pyridine-iron (II) chloride, 2,6-bis [1- (4-isopropylphenylimino) ethyl] pyridine-iron (II) chloride, 2,6- Bis [1- (4-methoxyphenylimino) ethyl] yridine-iron (II) chloride, 2,6-bis [1- (4-trifluoromethylphenylimino) ethyl] pyridine-iron (II) chloride and the corresponding iron (II) bromide and cobalt (II) chloride complexes.

The transition metal compounds (I) have a tridentate bisiminchelate ligand as the structural element (in formula (I) that structural element which is obtained with the components M ¹ , T, Q and A omitted). These tridentate ligands can be obtained, for example, from 2,6-diacetylpyridine by reaction with primary amines such as aniline, 4-methylphenylamine, 4-methoxyphenylamine, 4-trifluoromethylphenylamine or 4-t-butylphenylamine (see also J. Org. Chem. 1967, 32, 3246).

For a process for the production of transition metal compounds (I), reference is hereby expressly made to Brookhart et al., Macromolecules, 1999, 32, 2120-2130.

In process step a), one or more transition metal compounds (I) can be used side by side for olefin oligomerization.

In process step a), the transition metal compound (I) can be a cocatalyst, a strong neutral Lewis acid, an ionic compound with Lewis acidic cations or an ionic compound with a Brönstadt acid as a cation.

Suitable ionic compounds with Lewis acid cations fall e.g. under the general formula

L ¹⁺ (YX ¹ X ² X ³ X) ι "HVa)

in the

an element of the 1st or 2nd main group of the Periodic Table of the Elements, such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium, in particular lithium or sodium, or a silver, carbonium, oxonium, per - or partially alkyl and / or aryl-substituted ammonium, sulfonium or 1,1 '-dimethylferrocenyl cation,

Y an element of III. Main group of the periodic table of the elements means, in particular boron, aluminum or gallium, preferably boron,

X ¹ to X ⁴ independently of one another for hydrogen, linear or branched C 1 -C 1 -alkyl, preferably C 1 -C 4 -alkyl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl , t-butyl or n-hexyl, mono- or polysubstituted Ci- to Cio-alkyl, preferably Cι ~ to Cs-alkyl, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, C ₆ - to Cι ₆ aryl, preferably C ₆ -C to aryl, for example phenyl, which can also be substituted one or more times, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, for example pentafluorophenyl, alkylaryl with 1 to 10 C atoms, preferably 1 up to 6 carbon atoms in the alkyl radical and 6 to 14 carbon atoms, preferably 6 to 10 carbon atoms in the aryl radical, for example benzyl, fluorine, chlorine, bromine, iodine, C 1 -C 1 -to alkoxy, preferably C 1 ~ to Cs-alkoxy , such as methoxy, ethoxy or i-propoxy, or C ₆ - to -C ₆ aryloxy, preferably Cζ- to Cio-aryloxy, for example phenoxy, and

1 means 1 or 2.

The anion (YX ¹ X ² X ³ X ⁴ ) in a compound of the general formula (IVa) is preferably a non-coordinating counterion. Boron compounds, such as those in WO 91/09882, to which reference is expressly made here, should be emphasized will be called. Particularly suitable cations L can be traced back to the sodium or triphenylmethyl cation and to tetraalkylammonium cations, such as tetramethyl, tetraethyl or tetra-n-butylammonium, dimethylanilinium, or tetraalkylphosphonium cations, such as tetramethyl, tetraethyl or tetra-n-butylphosphonium , Preferred compounds (IVa) are, for example, sodium tetrakis (pentafluorophenyl) borate or sodium tetrakis [bis (trifluoromethyl) phenyl] borate.

The strong neutral Lewis acids are e.g. Compounds of the general formula

YX ⁵ X ⁶ X ⁷ HVb) in question in the

X ⁵ to X ⁷ independently of one another for hydrogen, linear or branched C 1 -C 1 -alkyl, preferably C 1 -C 6 -alkyl, such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl , t-butyl or n-hexyl, mono- or polysubstituted C ₁ -C ₁ -alkyl, preferably C ₁ -C ₆ -alkyl, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, C ₆ -C ₆ -aryl, preferably C ₆ - to Cio-aryl, for example phenyl, which can also be substituted one or more times, for example with halogen atoms such as fluorine, chlorine, bromine or iodine, for example pentafluorophenyl, alkylaryl with 1 to 10 C atoms, preferably 1 to 6 C atoms in the alkyl radical and 6 to 14 C atoms, preferably 6 to 10 C atoms in the aryl radical, for example benzyl or fluorine, chlorine, bromine or iodine.

Particularly preferred among the radicals X ⁵ to X ⁷ are those which have halogen substituents. Pentafluorophenyl should preferably be mentioned. Particularly preferred are compounds of the general formula (IVb) in which X ⁵ , X ⁶ and X ^{7 are} identical, preferably tris (pentafluorophenyl) borane. Furthermore, aluminum alkyl or aluminum haloalkyl compounds, for example triethyl, tri (n-hexyl) aluminum or di-i-propyl aluminum chloride, are particularly suitable cocatalysts (IVb). In addition, lithium and / or magnesium alkyls, for example (n-butyl) (n-octyl) magnesium, can also be used as compounds (IVb). Any mixtures of compounds (IVb) can also be used.

As a strong neutral Lewis acid, alumoxane compounds are further preferred among the cocatalysts. In principle, those compounds which have an Al — C bond are suitable as alumoxane compounds. Open-chain and / or cyclic alumoxane compounds of the general formula (IVc) or (IVd) are particularly suitable as cocatalysts.

in which

R ¹³ independently of one another denotes a C 1 -C ₄ -alkyl group, preferably a methyl or ethyl group, and r represents an integer from 5 to 30, preferably 10 to 25.

These oligomeric alumoxane compounds are usually prepared by reacting a solution of trialkylaluminum with water and include in EP-A 0 284 708 and US-A 4,794,096.

As a rule, the oligomeric alumoxane compounds obtained are present as mixtures of both linear and cyclic chain molecules of different lengths, so that r is to be regarded as the mean. The alumoxane compounds can also be present in a mixture with other metal alkyls, preferably with aluminum alkyls, such as triisobutyl aluminum or triethyl aluminum. Methylalumoxane (MAO) is preferably used, in particular in the form of a solution in toluene. The production of methylalumoxane can be found e.g. described in detail in EP-A 284 708.

Aryloxyalumoxanes, as described in US Pat. No. 5,391,793, amidoaluminoxanes, as described in US Pat. No. 5,371,260, aminoaluminoxane hydrochlorides, as described in EP-A 0 633 264, and siloxyaluminoxanes, as in EP-A 0 621 279, can also be used as cocatalysts described, or alumoxane mixtures are used.

The alumoxanes described are used either as such or in the form of a solution or suspension, for example in aliphatic or aromatic hydrocarbons, such as toluene or xylene, or mixtures thereof. The cocatalysts described can be used either as such or in any mixture.

The process according to the invention for the production of highly branched polyolefins can be carried out in a non-polar aliphatic or aromatic aprotic solvent, e.g. in heptane, i-butane, toluene or benzene, as well as in a polar aprotic solvent. Suitable polar aprotic solvents are e.g. Halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride or chlorobenzene and also linear or cyclic ethers such as diethyl ether or tetrahydrofuran, furthermore acetone, dimethyl sulfoxide, dirnethyl formamide, hexamethylphosphoric acid triamide or acetonitrile. Of course, any mixtures of the abovementioned solvents can also be used as long as these mixtures behave homogeneously. Dichloromethane, toluene, i-butane, pentane, heptane, chlorobenzene and acetonitrile and mixtures thereof, in particular toluene, i-butane and chlorobenzene, are particularly preferred.

The amount of solvent is usually measured so that the starting compounds are in dissolved form at the start of the reaction.

The oligomerization after step a) is usually carried out at temperatures in the range from -40 to 160 ° C., preferably in the range from -20 to 100 ° C. and particularly preferably from 0 to 80 ° C. The reaction times are generally between 0.1 and 120 minutes, depending on the reaction conditions chosen.

The oligomerization generally takes place at a pressure in the range from 0.1 to 1000 bar, preferably from 0.5 to 100 bar and particularly preferably in the range from 1 to 80 bar.

The concentration of transition metal compound (I) is generally set to values in the range from 10 ^{~ 9} to 0.1, preferably from 5 x 10 " ⁸ to 10 ^-2 and particularly preferably from 10 ^-6 to 5 x 10 ^{~ 2} mol / 1 set.

The initial concentration of ethylene is usually in the range of 10 ^-3 to 10 mol / 1, preferably mol / 1 in the range from 10 ^"2 to 5.

One or more transition metal compounds of the general formula (II) are added to the reaction mixture after step a). Preferred transition metal compounds are based on compounds (II) in which M ¹¹ titanium or zirconium,

R ⁹ to R ¹² C 1 -C 10 -alkyl or C ₃ - to C ₂ ι-organosilyl, where two adjacent radicals optionally form a condensed aromatic cycle,

T ', Q' is a hydrogen atom, a Ci to Cι ₀ alkyl or

C _{δ to} C ₂ o-aryl, a halogen atom, -OR ', -SR', -OSiR'3, -SiR ' ₃ , -CR " ₂ SiR' ₃ , for example -CH ₂ SiMe ₃ , -PR ' ₂ , -NR ' ₂ , for example -NMe ₂ , toluenesulfonyl, trifluoroacetyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl, 2,2,2-trifluoroethanesulfonyl,

CH ₂ , CH ₂ CH ₂ , CH (CH ₃ ) CH ₂ , CH (C ₄ H ₉ ) C (CH ₃ ) ₂ , C (CH ₃ ), (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 Sn, (CH ₂ ) Si or CH ₂ Si (CH ₃ ) ₂ ,

k 1, 2 or 3,

-0-, -S-, -NR '' - or -PR '' or a radical of the formula (III)

in which the substituents R ⁹ to R ^{12 have} the abovementioned meaning, and

R '' is methyl, ethyl, n- or i-propyl, n-, i- or t-butyl,

Cyclohexyl or phenyl or cyclopentadienyl, 3-methyl 'cyclopentadienyl, 3-n-butylcyclopentadienyl, indenyl, tetrahydroindenyl, tetramethylcyclopentadienyl, 3-trimethylsilylcyclopentadienyl or 3-phenylcyclopentadienyl, or

Z ^ and G together a substituted or unsubstituted aromatic or heteroaromatic structure of 4 to 10 ring carbon atoms or Z _k and R ⁹ and / or R ¹² together form a mono- or polycyclic aliphatic, aromatic or heteroaromatic ring system

mean.

The central metal M ¹¹ in the transition metal compounds (II) are early transition metals, ie those from group (IIIB), the group of lanthanides, for example lanthanum or yttrium, the group IVB, for example titanium, zirconium or hafnium, and the group VB, for example vanadium, or the group VIB of the periodic table of the elements, eg chromium or molybdenum, in question (see also Textbook of inorganic chemistry, Holleman-Wiberg, de Gruyter Berlin, 1985). Titanium, zirconium or hafnium are preferred. For the latter case, the metals M ¹¹ are in the mononuclear complexes (II) generally formally four times positively charged.

As a monoanionic η ⁵ -bonded cyclic ligand bearing the substituent - (Z ^) -, in addition to cyclopentadienyl (R ⁹ - R ¹² = H), there are also simply negatively charged five-membered aromatic carbocycles which, in addition to the Z radical, also occur one or more times Functional groups are substituted, for example with halogen such as fluorine, chlorine or bromine, linear or branched Ci- to C ₂ o ~ alkyl, preferably Cι ~ to Cι ₀ ~ alkyl, such as methyl, ethyl, n-propyl, i-propyl, n -Butyl or t-butyl, C ₃ - to Cio-cycloalkyl, preferably C ₃ - to C ₇ -cycloalkyl, such as cyclopropyl or cyclohexyl, or C ₆ - to Ci _ß- aryl, preferably Cξ- to Cιo ~ aryl, such as phenyl or naphthyl. Suitable aryl substituents also include, for example, C ₆ to C ₆ alkyl such as methyl or i-propyl or C ₆ to C 13 aryl, preferably C ₆ to Cio aryl, substituted by halogen such as fluorine, chlorine or bromine.

Two adjacent radicals, for example R ⁹ and R ¹⁰ or R ¹⁰ and R ¹¹ , can also together form a saturated or unsaturated cyclic or heterocyclic group which has 4 to 18, preferably 4 to 15, carbon atoms. This includes, for example, condensed aryl units. Accordingly, even substituted and unsubstituted indenyl, fluorenyl or benzindenyl systems are also suitable monoanionic η ⁵ -bound cyclic ligands.

Also suitable as radicals R ⁹ to R ^{12 are} C ₃ - to C ₃ o ~, preferably C ₃ - to C ₂ ι-organosilyl groups, -Si (R *) ₃ . The radicals R * can independently of one another C 1 -C 10 -alkyl, preferably C 1 -C ₇ -alkyl, for example methyl, ethyl or i-propyl, C ₃ - to Cio-cycloalkyl, preferably C ₃ - to C ₇ -cycloalkyl, for example cyclopropyl or cyclohexyl, C ₆ - to -C ₀ aryl, preferably phenyl, or alkylaryl with 1 to 4 carbon atoms in the alkyl and 6 to 10 carbon atoms in the aryl part, for example benzyl.

The radicals R ⁹ to R ¹² in a compound (II) can both agree or have different meanings.

As the metal M ¹¹ complexing, η ⁵ -bonded ligands among the abovementioned compounds, those which are derived from cyclopentadienyl, tetra-Ci to Cg-alkylcyclopentadienyl, indenyl, fluorenyl or benzindenyl are particularly suitable, the last three ligands also can be substituted one or more times with C 1 -C 6 -alkyl groups. Accordingly, preferred radicals bearing the substituent Z are cyclopentadienyl, tetra-Ci to C-alkylcyclopentadienyl, indenyl, benzindenyl and 1- to 3-fold Ci- to C ₄ -alkyl-substituted indenyl or benzindenyl. Cyclopentadienyl, tetramethylcyclopentadienyl or indenyl, in particular tetramethylcyclopentadienyl, is particularly preferably used.

Complexes (II) which have two η ⁵ -bound ligands are usually used. In these compounds, G represents a radical of the formula (III). The η ⁵ -bonded ligands can be identical in their substitution pattern or can differ in their ring system as such and / or their ring substitution pattern.

Suitable radicals Z are bivalent structural units based on monatomic bridge members, the free valences of which may be saturated by organic radicals R '. For example, the silylene (-SiR ' ₂ ^_ ),

Alkylene- (-CR ' ₂ -), Germanyl- (-GeR' ₂ -), Stannyl- (-SnR ' ₂ -), Boronyl- (-BR'-) or the oxo group (-0-). Two units Z (k = 2) covalently linked to one another can also form a bridge segment between the monoanionic η ⁵ -bonded ligand and the unit G. In a two-part bridge segment, Z does not necessarily have to exist in the form of two identical structural units. Among the two-part bridge segments are in particular the systems -SiR ' ₂ -SiR' ₂ - / -SiR ' ₂ -CR' ₂ - / -CR ' ₂ -CR' ₂ -, -CR '= CR'-, -0-CR ' ₂ - and -0-SiR' ₂ - in question. However, preference is given to using one-atom bridging bridge segments (k = 1), in particular to the systems -SiR ' ₂ - and -CR' ₂ -. The radicals R 'may Ci to C ₂ o alkyl, preferably C ₂ to Cι ₀ alkyl, for example methyl, ethyl or i-propyl, C ₃ - to Cio-cycloalkyl, preferably C ₃ - to C ₇ cycloalkyl, for example, cyclohexyl, C ₆ - to C-aryl, preferably C ₆ - to Cι ₀ aryl, especially phenyl, or alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 10 C atoms in the aryl moiety, for example benzyl, mean. Z can too form a mono- or polycyclic aliphatic, aromatic or heteroaromatic ring system with one or more radicals R ⁹ to R ¹² . Among the Z radicals, di-C 1 -C ₇ -alkyl-substituted silyl groups such as dimethylsilyl, diethylsilyl or di-i-propylsilyl are particularly preferred.

The unit G also includes, for example, the oxo (-0-), thio- (-S-), amido ((-NR "-) or the phosphido group (-PR" -). These groups are generally covalently and / or coordinatively linked to the metal center M ¹¹ . Furthermore, G can also mean a neutral two-electron donor such as -OR ", -SR", -NR " ₂ or -PR" ₂ . The last-mentioned residues G mostly have a coordinative connection to the metal center M via a free electron pair. G preferably represents an oxo or thio group, particularly preferably an amido unit. Substitutes R "in the radicals -NR" -, -PR "-, -OR", -SR ", -NR" ₂ or -PR " ₂ generally a hydrogen atom, C ₁ -C _{2 to} alkyl, for example methyl, ethyl, t-butyl or n-octyl, C ₃ to C ₀ cycloalkyl, for example cyclohexyl, Cg to cis aryl, for example phenyl or Naphthyl, C ₄ - to Cig heteroaryl, for example pyridyl, furyl or quinolyl, alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 10 C atoms in the aryl part, or C ₃ - to C ₃₀ -organosilyl, for example trimethylsilyl Particularly suitable radicals R "are sterically demanding groups such as C ₃ - to Cio-alkyl groups, for example i-propyl or t-butyl, the Cg to Cio-aryl group such as phenyl or substituted phenyl, and the alkylaryl group with 1 up to 6 C atoms in the alkyl and 6 to 10 C atoms in the aryl part, for example benzyl. -N (t-butyl-) is used particularly frequently as unit G. Furthermore, the unit G together with the unit Z or Z _{k can form} a substituted or unsubstituted aromatic or heteroaromatic structure of 4 to 16, preferably 4 to 10 ring carbon atoms.

The radicals T 'and Q' in compounds (II) can have the same general meaning as described for the corresponding radicals T and Q in the formula (I). T 'and Q' preferably represent

Halides, particularly preferably chloride or bromide, in particular chloride.

In connection with suitable transition metal compounds (II), reference is hereby expressly made to the disclosure of DE-A 197 07 236.

Particularly preferred compounds (II) are dimethylsilanediylbis (2-methyl-4- (1-naphthyl) indenyl) zirconium dichloride, dirnethylsilanediylbis (indenyl) zirconium dichloride, dimethylsilanediylbis (2-methylindenyl) zirconium dichloride, dimethylsilanedi bis (2-methylbenz [e] indenyl) zirconium dichloride, [dimethylsilanediyl (tetramethylcyclopentadienyl) (t-butyl) amido] titanium dichloride,

(Quinolin-8-yl) -2-indenyl-titanium (richloride), (quinolin-8-yl) -2-indenyl-titanium (trimethyl), (quinolin-8-yl) -2-indenyl-titanium (dichloride) , (Quinolin-8-yl) -2-benz [e] indenyl-titanium (trichloride), (quinolin-8-yl) -2-benz [e] indenyl-titanium (trimethyl), (quinolin-8-yl) -2-benz [e] indenyl-titanium (dichloride), (2-methyl-quinolin-8-yl) -2, 3,4, 5-tetraethyl-cyclopentadienyl-titanium (trichloride), (2-methyl -quinolin-8-yl) -2, 3, 4, 5-tetramethyl-cyclopentadienyl-titanium (trimethyl) and (2-methylquinoline-8-yl) -2,3,4,5-tetramethyl -cyclopentadienyl-titanium (dichloride).

The polymerization according to step b) can be initiated on the one hand by adding the transition metal compound (II) to the reaction mixture after step a), and on the other hand before adding the compound (II) the reaction mixture can be diluted by adding further solvent components. Furthermore, the transition metal compound (II) can be added to the reaction mixture both as such and in dissolved form, if appropriate also together with a further cocatalyst of the type described above.

Preferred cocatalysts in step b) are methyl alumoxane, magnesium, lithium or aluminum alkyls, e.g. Butyl octyl magnesium, butyllithium or triisobutyl aluminum, or any mixtures of these compounds with boranes and / or borates such as tris (pentafluorophenyl) borane or dimethylanilinium tetrakis (pentafluorophenyl) borate are added.

The polymerization process after step b) is usually in the temperature range from -100 to 300 ° C., preferably 0 to 200 ° C. and particularly preferably from 25 to 150 ° C. and in a pressure range from 0.5 to 300 bar, preferably 1 to 100 bar and particularly preferably carried out from 1 to 60 bar.

The process according to the invention can be carried out both in a single reactor and in two or more reactors connected in cascade. By adding the transition metal compounds (I) and (II) to the respective reactor cascades, their ratio can be varied during the production process. The ratio of the compounds (I) to (II) is generally in the range from 200: 1 to 1:50 and preferably in the range from 50: 1 to 1:10. It has a particularly advantageous effect on the number of alkyl branches if the ethene feed is stopped in process step b) and the polymerization is continued under the pressure conditions resulting from reaction step a) while consuming the remaining amount of ethene. Of course, the ethene supply can also be stopped only in the course of process step b). In a further embodiment, after the ethylene supply has been initially interrupted in step b), it is resumed in the course of the polymerization.

The (co) polymerization reaction after step b) can be interrupted and worked up in the usual way. For example, the reaction mixture can be added to an excess of low molecular weight alcohol such as methanol, ethanol or i-propanol and by treatment with a dilute mineral acid, e.g. Hydrochloric acid, optionally in a mixture with a low molecular weight alcohol.

The process according to the invention reproducibly gives highly branched polyolefins having at least 120, in particular at least 150, preferably at least 170 and particularly preferably at least 205 alkyl branches / 1000 carbon atoms in the polymer backbone.

The polyolefins obtained by the process according to the invention have average molecular weights M _w in the range from 10,000 to 2,000,000, preferably from 15,000 to 1,000,000 and particularly preferably from 20,000 to 500,000 g / mol. The polydispersities are in the range from 1.5 to 5.0, preferably from 1.5 to 3.0 and particularly preferably from 1.6 to 2.5.

The highly branched polymers obtainable by the process according to the invention are further distinguished by the fact that they have a high proportion of ethyl branches, no or almost no methyl branches and low proportions of butyl and hexyl or higher branches. The process according to the invention preferably gives highly branched polyolefins whose alkyl branches are at least 60, preferably at least 70 and particularly preferably at least 80% on ethyl side branches and at most 20, preferably at most 15 and particularly preferably at most 10% of butyl and hexyl and higher Show side branches. The highly branched polyolefins obtained have an elastomeric property profile and are generally completely amorphous. They show no melting points and have glass transition temperature values which are regularly below -10, preferably -30 and particularly preferably below -50 ° C.

The highly branched polyolefins obtained by the process according to the invention are suitable e.g. for impact modification of linear polyolefins or polymer blends made from thermoplastically processable materials. Suitable thermoplastic materials are, for example, polyamides such as so-called polyamide 6 or polyamide 6.6, polyacetals such as polyoxymethylene or polyesters such as polybutylene terephthalate.

In the process according to the invention, no dimeric coupling products from the 1-alkenes produced are observed. In addition, no interfering interactions are found between the olefin oligmerization and polymerization catalysts described. Furthermore, no unreacted 1-alkenes formed in step a) can be detected in the branched polyolefins formed, i.e. in step b) these compounds are completely incorporated into the polymer chain, so that a uniform product is obtained.

The invention is illustrated by the following examples.

Examples

The gel permeation chromatography of the polymer from experiment 9 was carried out on a Waters device (150 ° C.) with 1, 2, 4-trichlorobenzene as eluent (flow rate: 1 ml / min) against polyethylene standards at 140 ° C. in accordance with DIN 55 672 carried out.

The gel permeation chromatography of the polymers from experiments 1-6 was carried out using tetrahydrofuran as eluent (flow rate: 1.2 ml / min) against polystyrene standards at 35 ° C.

The ¹ H-NMR and ¹³ C-NMR spectra were recorded on a device from Bruker (ARX 300) with C ₂ D ₂ C1 ₄ as solvent.

The DSC spectra were generated on a device from Perkin-Elmer (Series 7) at a heating rate of 20 K / min.

Tetrahydrofuran and toluene were refluxed over sodium / benzophenone and distilled under inert gas. Methylalumoxane (MAO) was used as a 1.53 molar solution in toluene. It is a commercially available product from Witco.

The preparation of the catalyst complexes (Ia, Ib) and (II) as well as the polymerization reactions were carried out with the exclusion of air and moisture and using protective gas techniques known in metal-organic chemistry with nitrogen as the protective gas.

A. Preparation of the catalyst complexes

1. transition metal compounds (la, Ib)

a) 2,6-bis- [1- (2-methylphenylimino) ethyl)] pyridine

2,6-diacetylpyridine (1.5 g), 2-methylaniline ^■ (2.1 g) and p-toluenesulfonic acid (160 mg) were heated under reflux in benzene (50 ml) for 24 hours using a water separator. The cooled reaction mixture was diluted with diethyl ether (100 ml) and with aqueous sodium bicarbonate.

Washed solution (100 ml) and water (100 ml). The organic phase was dried over sodium sulfate and concentrated in vacuo. The residue obtained was washed with cold methanol (50 ml) and dried in vacuo. The yield of yellow solid was 80%.

(b) 2,6-bis- [1- (phenylimino) ethyl)] pyridine

The synthesis of the aforementioned ligand was carried out analogously to the procedure according to A.l.a), with the difference that aniline (1.86 g) was used instead of 2-methylaniline. The yield was 82%.

c) Transition metal compounds (la) (comparative catalyst) and (Ib) (catalyst according to the process of the invention) 2,6-bis- [1- (2-methylphenylimino) ethyl)] pyridine were added

(Ala)) or 2,6-bis- [1- (phenylimino) ethyl)] pyridine (Alb)) (1 mmol), dissolved in tetrahydrofuran (10 ml), with stirring to FeCl ₂ -4 H ₂ 0 ( 1.0 mmol) in tetrahydrofuran (10 ml). After stirring at RT for two hours, the volatile components were removed in vacuo and the residue was washed with diethyl ether (50 ml) and n-pentane (50 ml). The last solvent residues were removed in a high vacuum. The products (la) and (Ib) were each obtained in almost quantitative yield. 2) transition metal compound (II)

Dimethylsilanediyl bis (2-methyl-4- (1-naphthyl) indenyl) zirconium dichloride The aforementioned transition metal compound (II) was prepared according to the instructions from Spaleck et al., Organometallics 1994, 13, 954-963.

a.) Production of highly branched polyolefins

In a 2.0 1- (tests 1-6) or 1.6 1- (tests 7-9) pressure autoclave containing toluene (tests 1-6: 1000 ml, tests 7-9: 800 ml) and methylalumoxane (1 , 53-molar solution in toluene) were added with stirring (600 rpm) at a temperature of 40 ° C., the transition metal compound (Ib) or (Ia), the reaction vessel having been flushed with ethene gas beforehand. The ethene pressure was set to 2 bar and kept constant at this pressure during the first reaction phase (step a). The ethene feed was interrupted before the addition of the transition metal compound (II). After the addition of the transition metal compound (II), the polymerization reaction was carried out using the ethene in the reaction vessel (step b)). After cooling to room temperature, the reaction vessel was let down and the polymer solution was slowly introduced into 200 ml of ethanol, the reaction mixture was concentrated to a volume of approx. 400 ml and the polymer product was then dissolved in an excess of a mixture of dilute hydrochloric acid and methanol (approx. 1.5 l ) failed. The product filtered off was washed with methanol (300 ml) and the last solvent residues were removed in a high vacuum at 40 ° C. More detailed information on the reaction parameters of the polymerizations carried out in accordance with this general rule and the product properties of the polymers produced can be found in the table below.

Table:

(a) In the polyolefins obtained according to experiments 1 to 6, the alkyl branches mentioned are ethyl (80%), butyl (10%) and hexyl and higher side branches (10%); determined by ¹ C-NMR spectroscopy;

(b) First numerical value = reaction time for step a), second numerical value = reaction time for step b);

(c) comparative tests;

(d) polymerization in the presence of the

Catalysts (Ib) and (II) (This experiment demonstrates that when catalysts (Ib) and (II) are used simultaneously, i.e. when steps a) and b) are carried out simultaneously, highly branched amorphous polyolefins are obtained).

Claims

claims

1. A process for the homogeneous catalytic preparation of highly branched amorphous polyolefins with an elastomeric property profile from ethene, characterized in that in a first step

in which the substituents and indices have the following meaning:

R ^ R ² C ₄ - to Cig-heteroaryl or Cg to Cig-aryl with hydrogen substituents in the two vicinal positions to the point of connection between aryl or heteroaryl and N ^a or N ^b ,

R ³ , R ^{4 are} hydrogen, C _x - to -CC ₀ alkyl, C ₃ - to -CC ₀ cycloalkyl, C ₆ - to cig-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl and 6 to 14 C atoms in the aryl part or Si (R ⁸ ) with

R ⁸ Cι ~ to Cio-alkyl, C ₃ - to Cι ₀ cycloalkyl, Cg to Cig-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part,

R ⁵ , R ⁶ , R ^{7 are} hydrogen, Ci to Cio-alkyl, C ₃ - to Cio-cycloalkyl, Cg to Cig-aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁵ and R ⁶ and / or R ⁶ and R ⁷ each together form an annellated five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M ¹ Fe, Ru, Co, Rh, Ni or Pd

T, Q neutral or monoanionic monodentate ligands or T and Q together form a diketoenolate

10 unit or a C ₂ - or C -alkylene unit with a methyl ketone or a linear Cι ~ to C ₄ ~ alkyl ester or nitrile end group,

_] _ A a non or poorly coordinating anion,

m, p 0, 1, 2 or 3,

q 1, 2 or 3 and

20 n 1, 2 or 3

and optionally one or more cocatalysts in the form of strong neutral Lewis acids, ionic compounds with a Le

25 Wis acidic cation or ionic compounds with a Bronsted acid as a cation oligomerized in an inert solvent in a further step

b) at least one transition metal compound of the general

30 formula (II)

RIO

in which the substituents and indices have the following meaning: 5

R ⁹ to R ^{12 are} hydrogen, C 1 ~ to C ₁ -C 10 -alkyl, C ₃ - to C 1 -C 10 -cycloalkyl, C _e - to C 1 -C 10 -aryl, alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁹ and R ¹⁰ and / or R ¹¹ and R ¹² together form an anellated five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M ^{11 is} a metal from group IIIB, IVB, VB or VIB des

Periodic table of the elements,

T ', Q' is a hydrogen atom, a Ci to Cio-alkyl or

Cg to C ₂ o-aryl, a halogen atom, -OR ', -SR', -OSiR ' ₃ , -SiR' ₃ , -CR " ₂ SiR ' ₃ , -PR' ₂ , ~ NR ' ₂ , toluene - sulfonyl, trifluoroacetyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl, 2,2,2-trifluoroethanesulfonyl,

-CR ' ₂ -, -SiR' ₂ -, - GeR ' ₂ -, -SnR' ₂ -, -BR'- or -0- with

R 'Ci to C ₂ o-alkyl, C ₃ - to -C ₀ cycloalkyl, C ₆ - to cig-aryl, alkylaryl with 1 to 10 carbon atoms in the

Alkyl and 6 to 10 carbon atoms in the aryl part, Cι ~ to C ₂ o-alkoxy, C ₃ - to Cio-cycloalkoxy, Cg to Cig-aryloxy or alkylaryloxy with 1 to 10 carbon atoms in the alkyl and 6 to 10 carbon atoms in the aryl part,

k 1, 2 or 3,

-O-, -S-, -NR '' -, -PR ", -BR '' -, -OR '' -, -SR '' -, -NR '' ₂ , -PR '' ₂ or or a Rest of formula (III)

in which the substituents R ⁹ to R ^{12 have} the abovementioned meaning,

R '' hydrogen, -C ~ to C ₂ o-alkyl, C ₃ - to Cι ₀ cycloalkyl, Cg- to Cι ₅ aryl, alkylaryl with 1 to 10

C atoms in the alkyl and 6 to 10 C atoms in the aryl part or C ₃ - to C ₃ o-organosilyl, or

Z _k and G together form a substituted or unsubstituted aromatic or heteroaromatic structure of 4 to 16 ring carbon atoms or

2. The method according to claim 1, characterized in that one uses transition metal compounds (I) in which the substituents and indices have the following meaning:

R ^ R ² 4-i-propylphenyl, 4-methylphenyl, 4-methoxyphenyl or phenyl,

R ³ , R ^{4 are} hydrogen, methyl, ethyl, i-propyl, t-butyl or triorganosilyl,

R ⁵ , R ⁶ , R ^{7 are} hydrogen or methyl,

M ¹ iron or cobalt and

T, Q halide ions or trifluoromethanesulfonate.

Process according to claims 1 or 2, characterized in that transition metal compounds (I) are used in which the substituents and indices have the following meaning: R ^ R ² 4-i-propylphenyl, 4-methylphenyl, 4-methoxyphenyl or phenyl,

R ³ , R ^{4 are} hydrogen, methyl, ethyl, i-propyl, t-butyl or triorganosilyl,

R ⁵ , R ⁶ , R ^{7 are} hydrogen or methyl,

M ¹ iron or cobalt,

T methyl,

Q chloride, bromide or trifluoromethanesulfonate and

A tetrakis (3,5- bis- (trifluoromethylphenyldborate,

B [C ₆ F ₅ ] ₄ -, BF ₄ ^" , SbFg-, A1F ₄ "_' AsFg ". PF ₆ ^~ or trifluoroacetate.

Process according to claims 1 to 3, characterized in that transition metal compounds (II) are used in which the substituents and indices have the following meaning:

M ¹¹ titanium or zirconium,

R ⁹ to R ¹² Ci to Cio-alkyl or C ₃ to C ₂ -organosilyl, where two adjacent radicals optionally form a condensed aromatic cycle,

T ', Q' is a hydrogen atom, a Ci to Cio-alkyl or

Cg-bis C ₂ ^_ o aryl group, a halogen atom, -OR ', -SR', -OSiR'3, -SiR'3, -CR _'2 SiR' _3, -PR _'2 / "NR' _2, toluene- sulfonyl, trifluoroacetyl, trifluoromethanesulfonyl,

Nonafluorobutanesulfonyl or 2, 2, 2-trifluoroethanesulfonyl.

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 Sn, (CH ₂ ) ₄ Si or CH ₂ Si (CH ₃ ) ₂ ,

1, 2 or 3, G -0-, -S-, -NR '' - or -PR '' - or a radical of the formula (III)

in which the substituents R ⁹ to R ^{12 have} the abovementioned meaning,

R 'is methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, cyclohexyl or phenyl or cyclopentadienyl, 3-methylcyclopentadienyl, 3-n-butylcyclopentadienyl, indenyl, tetrahydroindenyl, tetramethylcyclopentadienyl, 3-trimethylsilylcyclopentadienyl or 3-phenylcyclopentadienyl.

Process according to Claims 1 to 4, characterized in that boranes, magnesium, lithium or aluminum alkyls, aluminum haloalkyls or alumoxanes are used as cocatalysts in steps a) and / or b).

Process according to claims 1 to 5, characterized in that process steps a) and b) are carried out in a stirred tank cascade.

Use of transition metal compounds of the general formula (I)

in which the substituents and indices have the following meaning:

R ^! , R ² C ₄ - to Cig heteroaryl or Cg to C ₁₆ aryl with hydrogen substituents in the two vicinal

Positions to the junction between aryl or heteroaryl and N ^a or N ^b ,

R ³ , R ⁴ hydrogen, Cι ~ to Cio-alkyl, C ₃ - to Cio-cycloalkyl, Cg- to Cig-aryl, alkylaryl with 1 to 10 C-atoms in the alkyl and 6 to 14 C-atoms in the aryl part or Si (R ⁸ ) ₃ with

R ⁸ Ci- to Cio-alkyl, C ₃ - to -CC ₀ cycloalkyl, Cg- bis

Cig-aryl, alkylaryl with 1 to 10 C atoms in the alkyl and 6 to 14 C atoms in the aryl part,

R ⁵ , R ⁶ , R ⁷ hydrogen, Cι ~ to Cio-alkyl, C ₃ - to Cio-Cycloalkyl, Cg- to Cig-Aryl, alkylaryl with 1 to

10 carbon atoms in the alkyl and 6 to 14 carbon atoms in the aryl part or Si (R ⁸ ) ₃ or functional groups based on the elements of groups IVA to VIIA of the periodic table of the elements or R ⁵ and R ⁶ and / or R ⁶ and R ⁷ together form an annellated five-, six- or seven-membered aliphatic or aromatic, substituted or unsubstituted carbo- or heterocycle,

M ¹ Fe, Ru, Co, Rh, Ni or Pd

A a non or poorly coordinating anion,

m, p 0, 1, 2 or 3,

q 1, 2 or 3 and

n 1, 2 or 3 and optionally one or more cocatalysts in the form of strong neutral Lewis acids, ionic compounds with a Lewis acidic cation or ionic compounds with a Bronsted acid as a cation

in the production of highly branched amorphous polyolefins with elastomeric properties from ethene.