NO312072B1 - Process for Preparation of Highly Active, Stable Metallocene Catalyst Systems and Formulation Prepared by the Process - Google Patents

Abstract

A process for the production of homogeneous mixtures (I)containing (a) metallocene(s), (b) co-catalyst(s) and (c) formulation media, in which the preparation of the catalyst system (a + b) comprises: (A) direct preparation by known methods in the hydrocarbon used (HC), or (B) suspending, dispersing or dissolving the isolated metallocene-based catalyst components in HC, or (C) adding a solution of the components in low-boiling solvent (made by known methods) to HC and then removing the low-boiling solvent, optionally with the use of (D) conventional inorganic or organic support materials, auxiliary substances and/or additives etc. Also claimed is a formulation obtained by this process.

Description

The present invention relates to a method for producing highly active, stable metallocene catalyst systems and formulation produced by the method.

Metallocene catalyst systems are gaining increasing importance as a new generation of catalyst systems for the production of polyolefins ("Single Site Catalysts"). These new catalysts essentially consist, as already known from classic Ziegler-Natta catalysis, of a transition metal compound as catalyst and a co-catalyst component, for example an alkylaluminoxane, especially methylaluminoxane. Cyclopentadienyl, indenyl or fluorenyl derivatives from group IVa in the periodic table of the elements are preferred as transition metal compounds. In contrast to conventional Ziegler-Natta catalysts, in addition to high activity and productivity, such catalyst systems also provide the opportunity for targeted control of product properties depending on the components used and reaction conditions, and also access to hitherto unknown polymer structures with promising properties in terms of technical applications .

Many publications have appeared in the literature relating to the production of special polyolefins using such catalyst systems. A disadvantage in almost all cases, however, is the fact that in order to achieve acceptable productivity, a high excess of alkylaluminoxanes in relation to the transition metal components is needed (usually the ratio between aluminum in the form of alkylaluminoxanes and transition metal is about 1000:1). Due to the high price of alkylaluminoxanes on the one hand, and in many cases necessary additional polymer purification steps ("deashing steps") on the other hand, polymer production on a technical scale on the basis of such catalyst systems is often uneconomical. In addition, for the formulation with alkylaluminoxanes, especially methylaluminoxane, the solvent toluene is often used to achieve storage stability of the highly concentrated formulations (strong tendency to gel in the aluminoxane solution), and with regard to the area of application for the final resulting polyolefins, this is of toxicological causes increasingly undesirable.

With these catalyst systems, or formulations for such, we are dealing with very sensitive substances that can have their polymerization activity reduced within a few hours or days.

Due to the high cost of these modern catalyst systems, such activity reductions are not acceptable. For economic reasons, there is therefore a need for catalysts or catalyst systems which, after manufacture, remain highly active for a longer period of time, or even have increased activity.

According to WO 93/23439, stability is to be achieved in metallocene catalyst systems through extensive variations in manufacturing conditions, especially temperature treatment.

This method is, on the one hand, labor-intensive and, on the other hand, not generally applicable due to the sensitivity of the system.

The aim of the present invention is to overcome these disadvantages and develop homogeneous formulations of metallocene-based catalyst systems which at least retain their high polymerization activity over a longer period of time.

Unexpectedly, it has now been found that the polymerization activity of metallocene catalyst systems in the form of liquid or solid formulations contained in paraffin can be permanently stabilized. The definition "formulation" here includes catalyst systems in high-boiling hydrocarbons (paraffins) which at room temperature have an oily or waxy consistency, and in which the components are dissolved, suspended or dispersed by means of a suitable mixing device.

An object of the invention is thereby a method for producing homogeneous mixtures consisting essentially of at least one metallocene, at least one cocatalyst and dispersion/suspension media or solvents, where the homogeneous mixture is produced by A) producing the metallocene-based catalyst systems directly in the dispersion/suspension medium or solvents, or by B) dissolving, suspending or dispersing the isolated metallocene-based catalyst components in the dispersion/suspension medium or

the solvent, or by

C) mixing the solution of the metallocene-based catalyst component, prepared according to known methods, in a low-boiling solvent together with the dispersion/suspension medium or the solvent in a first step, and then removing the low-boiling solvent by

distillation, possibly with the use of

D) common organic or inorganic carrier materials, auxiliaries and/or additives, as well as additives, characterized by the fact that natural or synthetic, commercially available, long-chain, optionally branched, liquid or solid non-aromatic hydrocarbons are used as dispersion/suspension medium or solvent boiling point above 150 °C and viscosities of at least 1 Pa.s at 25 °C.

A further object of the invention is a formulation produced by the method according to the invention.

The dispersion or suspension media used in the method according to the invention are all natural or synthetic, commercially common, long-chain, optionally branched, liquid or solid hydrocarbons with a boiling point above 150 °C, preferably above 200 °C, and with a viscosity of at least 1 Pa.s at 25 °C.

These compounds belong to the product group with the so-called white oils, e.g. Witco White Mineral Oil Parol® (trademark of Witco Polymers + Resins B.V., The Netherlands), vaselines as well as paraffinic waxes, e.g. Terhell® (company Schumann).

The hydrocarbon used is independent of the organometallic compound and is aimed primarily at the practical requirements regarding the subsequent use.

As cocatalysts used in the method according to the invention, compounds of the elements in groups II A, III A and IV A in the periodic table of the elements are used, preferably organo-aluminum, organo-boron, organo-zinc or organo-magnesium substances, alone or in mixtures, or as complex salts , for example PjR^Al, R^Vb and R<*>R<2>Mg, where <R1,> R<2> and R<3>, optionally independently of each other, are optionally alkyl residues containing heteroatoms, e.g. .: tributylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diisobutylaluminum chloride, isobutylaluminum dichloride, diethylaluminum iodide, diisobutylaluminum hydride, diethylaluminum ethoxide, isoprenylaluminum, dimethylaluminum chloride, methylaluminoxane, methylaluminum sesquichloride, tetraisobutyldialuminoxane, trimethylaluminum and/or triethylaluminum, preferably in admixture with at least one of the aforementioned compounds diethyl aluminum hydride, hexaisobutyltetraaluminoxane, diethyl(dimethylethylsilanolato)aluminum, diethyl-(ethylmethylsilanolato)aluminum, diisobutyl-(methylsilanolato)aluminum, tridodecyl aluminum, tripropylaluminium, dipropylaluminum chloride, dibutylmagnesium, butylethylmagnesium, butyloctylmagnesium, butyloctylmagnesium ethoxide, ethylaluminum propoxychloride , triethylboron, tris[pentafluorophenyl]borane and salts thereof.

Metallocene compounds described in EP-A-0 480 390, EP-A-0 413 326, EP-A-0 530 908, EP-A-0 344 887, EP-A-0 420 436, EP-A -0 416 815 and EP-A-0 520 732.

These are particularly compounds with the general formula

where

Cp = cyclopentadienyl, indenyl, fluorenyl residue,

R,R' = same or different alkyl, phosphine, amine, alkyl ether or aryl ether groups with

0<a<4,0<a'<4,

Cp' = one of the groups Cp, or

Cp' = -NR"- with R" = alkyl or aryl residue with a=1, and

Q = a single or multi-link bridge

between Cp and Cp', where R<1> and R2 are the same or different and are a hydrogen atom, a C10-alkyl group or a C6-10-aryl group, and Z denotes

carbon, silicon or germanium and b = 0, 1,2 or 3,

M = a transition metal from groups 3 to 6 (IUPAC Notation), especially Zr or

hf

X = halogen, especially Cl or Br, and

n = oxidation number of M reduced by 2.

As bridged ligands - Q(CpRa)(Cp'R'a') in the general formula (1) - the following compounds can in particular be used: dimethylsilyl-bis(1-indene), dimethylsilyl-bis(1-cyclopentadiene), 2, 2-propyl-bis(1-indene), 2,2-propyl-bis(trimethylcyclopentadiene), 2,2-propyl-bis(5-dimethylamino-1-indene), 2,2-propyl-bis(6 -dipropylamino-1 -indene), 2,2-propyl-bis(4,7-bis(dimethylamino-1 - indene), 2,2-propyl-bis(5-diphenylphosphmo-1 -indene), 2, 2-propyl-bis(4,5,6,7-tetrahydro-1-indene), 2,2-propyl-bis(4-methyl-1-indene), 2,2-propyl-bis(5-methyl- 1-indene), 2,2-propyl-bis(6-methyl-1-indene), 2,2-propyl-bis(7-methyl-1-indene), 2,2-propyl-bis(5-methoxy -1 - indene), 2,2-propyl-bis(4,7-dimethoxy-1-indene), 2,2-propyl-bis(2,3-dimethyl-1-indene), 2,2-propyl- bis(4,7-dimethyl-1-indene), 2,2-propyl-bis(1-cyclopentadiene), 2,2-propyl-bis(l-indene), diphenylmethyl-bis(l-indene), diphenylmethyl- bis(l-cyclopentadiene), diphenyl-methyl-bis(l-indene), diphenylsilyl-bis(1-indene), diphenylsilyl-bis(1-cyclopentadiene), diphenylsilyl-bis( 1-indene), ethylene-bis(1-indene), ethylene-bis(trimethylcyclopentadiene), ethylene-bis(5-dimethylamino-1-indene), ethylene-bis(6-dipropylamino-1-indene), ethylene-bis (4,7-bis(dimethylamino)-1-indene), ethylene-bis(5-diphenylphosphino-1-indene), ethylene-bis(4,5,6,7-tetra-hydro-1-indene), ethylene -bis(6-methyl-1-indene), ethylene-bis(7-methyl-1-indene), ethylene-bis(5-methoxy-1-indene), ethylene-bis(4,7-dimethoxy-1- indene), ethylene-bis(2,3-dimethyl-1-indene), ethylene-bis(4,7-dimethyl-1-indene), ethylene-bis(9-fluorene), ethylene-bis(1-cyclopentadiene) , ethylene-bis( 1 -indene).

As non-bridged ligands (formula (1) with b = 0), the following compounds can preferably be used: cyclopentadiene, fluorene, indene and their mono- or multi-alkylated derivatives, where the alkyl residue can contain 1-10 C atoms.

According to the invention is preferred

[bis(cyclopentadienyl)]zirconium dichloride,

[bis(methylcyclopentadienyl)]zirconium dichloride,

[bis(n-propylcyclopentadienyl)]zirconium dichloride,

[bis(iso-butylcyclopentadienyl)]zirconium dichloride,

[bis(cyclopentylcyclopentadienyl)]zirconium dichloride,

[bis(benzylcyclopentadienyl)]zirconium dichloride,

[bis(octadecylcyclopentadienyl)]zirconium dichloride,

[bis(n-butylcyclopentadienyl)]titanium dichloride,

[bis(n-butylcyclopentadienyl)]zirconium dichloride,

[bis(n-butylcyclopentadienyl)]halium dichloride,

[bis(indenyl)]zirconium dichloride,

[bis(indenyl)]zirconium dimethyl,

[bis(tetrahydro-indenyl)]zirconium dichloride,

[ 1,2-ethylene-bis(indenyl)]zirconium dichloride,

[ 1,2-ethylene-bis(indenyl)]hamium dichloride,

[ 1,2-ethylene-bis(tetrahydroindenyl)]zirconium dichloride,

[Dimethylsilyl-bis(1H-inden-1-yl)]zirconium dichloride,

[Dimethylsilyl-bis(1H-inden-1-yl)]halium dichloride.

As inorganic carrier materials used in the method according to the invention, porous oxides of one or more of the elements in groups II A, III A or IV A in the periodic table of the elements are used, such as ZrO2, TiO2, B2O3, CaO, ZnO, BaO, preferably aluminum silicates (zeolite) A1203 and MgO, and especially SiO2 (DE 44 09 249).

As organic carrier materials used in the method according to the invention, for example porous, partially polymeric compounds such as polyethylene, polypropylene, polystyrene and sugar derivatives (starch, amylose, cyclodextrin) come into consideration.

For the preparation of the formulation according to the invention, there are initially different possibilities, e.g.: M1) preparation of the metallocene-based catalyst systems in dispersion /the suspension medium or solvent (paraffin) according to the invention M2) dissolve, suspend or disperse isolated metallocene-based cata lysator components in the dispersion/suspension medium or solvent

(kerosene) according to the invention

M3) mixing non-aromatic solvents or dispersants with solutions of the metallocene-based catalyst systems and subsequent separation of the solvent by distillation so that the solution, suspension or dispersion according to the invention remains.

For the preparation of the formulation, the catalyst components can be used in pure form, as well as in a supported form on a suitable carrier material. If the catalyst components are used in pure form, the carrier material as well as auxiliaries, additives and additives can be added by the possible methods M1-M3 at the desired time.

The following examples illustrate the synthesis of the metallocene catalyst system according to the requirements, as well as the testing of these by polymerization.

Example 1

Methylaluminoxane in Witco Parol® (trademark of Witco, The Netherlands).

402 g of toluene MAO solution (Al tot. 13.2%; Al as TMA 3.19%) and 219 g of Witco Parol® were filled into a 1 L flask equipped with a thermometer and wall-close stirrer under nitrogen as a protective gas atmosphere . The flask contents were heated to a maximum of 32°C in an oil bath and vacuum was applied. The distilled toluene was condensed in a freezer trap. With decreasing toluene content in the suspension, the vacuum could be strengthened. The toluene residue was distilled off within 3 hours at < 1 mbar.

A viscous and milky, cloudy suspension was obtained.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 13.4%

Al as TMA: 1.5%

Example 2

Methylaluminoxane in Witco Petroleum Jelly Snowwhite MD® (Vaseline, Witco, The Netherlands).

Under nitrogen as a protective gas atmosphere, 130.1 g of toluene MAO solution (Al tot. 13.2%; Al as TMA 3.19%) and 85.1 g of Witco were filled into a 500 ml shot tube equipped with a stirrer Petroleum Jelly Snowwhite MD®. After heating to 55-60 °C in an oil bath, the mixture became homogeneous. The toluene was distilled off in vacuum and condensed in a freezer trap. The vacuum was continuously increased to below 1 mbar and the bath temperature was maintained at a maximum of 65 °C. After complete removal of the toluene, a colorless, homogeneous, waxy mass was obtained which was liquid from ca. 60 °C.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 12.0%

Al as TMA: 1.9%

Example 3

Methylaluminoxane in paraffinic wax

33.5 g of methylaluminoxane (solid) and 16.8 g of paraffin (Terhell 5605®, company Schumann) were heated under nitrogen in a round bottom flask with wall-close stirrers. At a bath temperature of 65-70 °C, a cloudy melt was obtained. The forge

was allowed to solidify under stirring and was then detached from the flask wall. After cooling under external cooling with dry ice, the solid could be divided into a fine-grained, pourable solid.

The powder which contained approx. 66% MAO, was not pyrophoric or self-igniting.

Al total: 26.1%

Al as TMA: 3.5%

Example 4

Methylaluminoxane in Witco Parol®

26.3 g of a finely powdered MAO solid (Al total 39.2%) was stirred under argon as protective gas atmosphere with 7.3 g of white oil (Witco Parol®). A colorless, waxy mass was obtained.

The powder which contained approx. 78% MAO was not pyrophoric or self-igniting and showed only moderate gas evolution when in contact with water. When placed on moist filter paper, charring without self-ignition could be observed.

Al total: 30.1%

Al as TMA: 3.6%

Example 5

Dispersion of methylaluminoxane in petrolatum

In a 500 ml shot tube equipped with a stirrer, 120 g of toluene MAO solution (Al tot. 13.2%; Al as TMA 3.19%) and 78.5 g of vaseline white DAB 10 were filled under nitrogen as a protective gas atmosphere. VARH AB (company Schumann). After heating to 55-60 °C in an oil bath, the mixture was homogeneous. The toluene was distilled off in vacuum and condensed in a freezer trap. The vacuum was continuously increased to below 1 mbar and the bath temperature was maintained at a maximum of 65 °C. After complete removal of the toluene, a colourless, homogeneous dispersion was obtained which was liquid from approx. 60 °C.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 12.3%

Al as TMA: 1.6%

Example 6

Suspension of methylaluminoxane and metallocene in white oil

In a stirrer, 60.5 g of a toluene MAO solution (Al content 13.2%; Al as TMA 3.19%) was filled under argon as a protective gas atmosphere. To this solution was added 2.0 g of EURECEN® 5036 (trademark of Witco GmbH, Bergkamen - 1,2-ethylene-bis-(1-indenyl)zirconium dichloride) and stirred for 30 minutes. 39 g of white oil Witco Parol® was added to this dark brown solution and heated to 40 °C. The toluene was distilled off in a vacuum of up to 0.1 mbar and condensed in a freezer trap.

56.6 g of a brown, waxy catalyst mass were obtained.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 14.11%

Zr: 0.77%

Example 7

Implementation as in example 6. Before use in polymerization, the mixture was subjected to a 24-hour aging process in toluene.

Example 8

Implementation as in example 6. Before use in polymerization, the mixture was subjected to a 48-hour aging process in toluene.

Example 9

Suspension of supported MAO/metallocene/silica catalyst system in Witco Parol®

Under argon as a protective gas atmosphere, 23 g of supported catalyst system (TA 02954, research product from the company Witco GmbH; Al content 23.9%, Zr content 1.1%) and 53.7 g white oil Witco Parol® were mixed in a stirring vessel. . A dark brown suspension was obtained.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 7.17%

Zr: 0.33%

Example 10

Metallocene/methylaluminoxane/silica suspension in white oil

203.5 g of a 10% methylaluminoxane solution in toluene (Al content 5, 0%).

18.8 g of silica (SYLOPOL 2104®, company Grace, with 5% water content) was rinsed with 1.5 g of distilled water for approx. 10 min, filled in the dosing device for solids and slowly added to the stirred methylaluminoxane solution. During gas development

(methane gas) the temperature thereby rose to 65 °C. After the addition was finished, stirring was continued until room temperature was reached, and 2.44 g EURECEN® 5036 (trademark of Witco GmbH, Bergkamen - 1,2-ethylene-bis-(1-indenyl)-zirconium dichloride) was then added. It was now stirred for 1.5 h, whereby the contents of the flask were colored reddish brown. Then 121.2 g of white oil Witco Parol® was added, and an approx. 25% suspension.

Now the toluene was completely distilled off at a maximum of 45 °C and a vacuum of up to 0.1 mbar for 6 h. A red-brown, highly viscous suspension was obtained.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 5.25%

Zr: 0.27%

Example 11

Metallocene/methylaluminoxane/silica suspension in white oil

Under a nitrogen protective gas atmosphere, to 52.4 g of methylaluminoxane supported on silica (SYLOPOL 2104®) with an aluminum content of 23.8% was added 3.14 g of EURECEN® 5036. To this solid mixture was added 111.1 g of white oil Witco Parol ® and stirred for a period of 2 h. A clear, curry-coloured, 33% suspension was obtained.

The suspension was neither pyrophoric nor self-igniting, and with water a slight evolution of gas occurred.

Al total: 7.48%

Zr: 0.38%

Comparative examples 12 and 13

In comparative examples 12 and 13, an MAO solution which is common in the trade and which is sold by Witco GmbH, Bergkamen under the trade mark EURECEN® Al 5100/1 OT was used and, together with the other catalyst components, was dosed directly into the polymerization reactor. Concentration of the active catalyst material is given in tables 1 and 2.

Polymerization results:

Claims (8)

1. Method for producing homogeneous mixtures consisting essentially of at least one metallocene, at least one cocatalyst and dispersion/suspension media or solvents, where the homogeneous mixture is prepared by A) producing the metallocene-based catalyst systems directly in dispersion/suspension -the medium or the solvents, or by B) dissolving, suspending or dispersing the isolated metallocene-based catalyst components in the dispersion/suspension medium or the solvent, or by C) mixing the solution of the metallocene-based catalyst component, prepared according to known methods, in a low-boiling solvent together with the dispersion/suspension medium or the solvent in a first step, and then remove the low-boiling solvent by distillation, possibly using D) common organic or inorganic carrier materials, auxiliaries and/or additives, as well as additives, characterized in that natural or synthetic, commercially available, long-chain, optionally branched, liquid or solid non-aromatic hydrocarbons with a boiling point above 150 °C and viscosities of at least 1 Pa.s at 25 °C. 2. Method according to claim 1, characterized in that organic aluminum compounds are used as cocatalysts. 3. Method according to claims 1 and 2, characterized in that aluminoxanes are used as cocatalysts. 4. Method according to claim 1, characterized in that organic boron compounds are used as cocatalysts. 5. Method according to claims 2 and 3, characterized in that methylaluminoxanes are used as cocatalysts. 6. Method according to claim 1, characterized in that one or more metallocenes with the general formula (1) are used as catalyst components where Cp is a cyclopentadienyl, indenyl, fluorenyl radical, R,R' are the same or different and are alkyl, phosphine, amine, alkyl ether or aryl ether groups with 0<a<4, 0<a'<4, Cp' is one of the groups Cp, or Cp' is -NR"- where R" is an alkyl or aryl radical with a=1, and Q is a single or multi-link bridge between Cp and Cp', where R<1> and R2 are the same or different and are a hydrogen atom, a C1-10 alkyl group or a C6-10 aryl group, Z is carbon, silicon or germanium, and b is 0, 1, 2 or 3, M is a transition metal from groups 3 to 6 (IUPAC Notation), especially Zr or hf X is halogen, especially Cl or Br, and n is the oxidation number of M reduced by 2. 7. Method according to claims 1 and 6, characterized in that one or more metallocenes selected from among are used as catalyst component [bis(cyclopentadienyl)]zirconium dichloride, [bis(methylcyclopentadienyl)]zirconium dichloride, [bis(n-propylcyclopentadienyl)]zirconium dichloride, [bis(iso-butylcyclopentadienyl)]zirconium dichloride, [bis(cyclopentylcyclopentadienyl)]zirconium dichloride, [bis(benzylcyclopentadienyl)]zirconium dichloride Zirconium dichloride, [bis(octadecylcyclopentadienyl)]zirconium dichloride, [bis(n-butylcyclopentadienyl)]titanium dichloride, [bis(n-butylcyclopentadienyl)]zirconium dichloride, [bis(n-butylcyclopentadienyl)]halium dichloride, [bis(indenyl)]zirconium dichloride, [bis (indenyl)]zirconium dimethyl, [bis(tetrahydro-indenyl)]zirconium dichloride, [ 1,2-ethylene-bis(indenyl)]zirconium dichloride, [ 1,2-ethylene-bis(indenyl)]hafnium dichloride, [ 1,2-ethylene -bis(tetrahydroindenyl)]zirconium dichloride, [dimethylsilyl-bis(1H-inden-1-yl)]zirconium dichloride, [dimethylsilyl-bis(1H-inden-1-yl)]hafnium dichloride. 8. Formulation, characterized in that it is produced by a method according to claim 1.