CZ449199A3 - Polymerization process of olefins in gaseous phase - Google Patents

Abstract

The gas phase polymerization process is carried out in the presence supported noble metal catalyst. Way includes a pre-polymerization step that can be performed in-situ, in particular, the prepolymer can be prepared in the dry phase. For example, the catalyst may comprise a transition complex metal with limited geometry carried on essential oil and used in presence of an activator. The prepolymerization step increases activity catalyst.

Description

The invention relates to a process for the polymerization of olefins and in particular to a process for homopolymerization of ethylene or copolymerization of ethylene and alpha-olefins in the gas phase using a pre-polymerized noble metal complex catalyst.

BACKGROUND OF THE INVENTION

The bases of the traditional olefin polymerization catalysts are the transition metal salts of Group IV and VIII in combination with basic alkyls of metals of I. and III. groups of the Periodic Table of the Elements. These catalysts, known as Ziegler-Natta catalysts, are used in solution, suspension and gas phase polymerization of olefins. Another catalyst system used in olefin polymerization is the tremorous oxide catalysts, often referred to as Phillips-type catalyst systems.

The problem that occurs when these catalyst systems are used in the gas phase is that they control the morphology of the polymer being prepared. The morphology of the polymers prepared in the gas phase is improved by the use of prepolymerization processes in which, as a rule, in the first stage one or more olefins are contacted with a Ziegler-Natta catalyst resulting in the formation of a prepolymer in the form of solid particles. In the second step the prepolymer is introduced

01-2993-99-Ce under gas-phase polymerization conditions in contact with one or more olefins and the polymers produced are obtained directly in powder form. In this way, the morphology of the final polymer can be improved. A typical prepolymerization process is described in EP 99774.

Cyclopentadienyl metal complex catalysts are also widely used in the polymerization of olefins. These complexes can be used in catalyst systems containing a bis (cyclopentadienyl) transition metal complex and a cocatalyst. Such bis (Cp) transition metal complexes are referred to as metallocenes, in which the transition metal is generally titanium or zirconium and which can be cocatalyzed with aluminum compounds, for example aluminoxanes. When used in the gas phase, these bis (Cp) metallocene systems can be deposited on silica (silica).

More recently, another type of transition metal complex has been used to prepare olefin polymers. These complexes have a single cyclopentadienyl ring ligand and have a heteroatom attached to the metal atom. These complexes can also be used in conjunction with aluminoxanes. these geometry limiting catalysts are described in patents EP 420436 and EP 416815.

Similar catalyst systems are described in patents EP 4180044 and WO 92/00333. In these systems, the catalyst is prepared as the product of a complex of mono (cyclopentadienyl) heteroatom-ionic ionic compound and these systems are referred to as ionic mono (cyclopentadienyl) catalysts. Typical examples of ionic activators for these systems are borates.

01-2993-99-Ce β β β β β β e <& β

The complexes described above may optionally be prepolymerized. For example, WO 93/23439 discloses supported alumoxane-activated bis (Cp) metallocene catalyst systems which may optionally be prepolymerized and thereby impart greater strength to the catalyst particles. Herein, the prepolymerization is carried out in the slurry phase at a temperature ranging from -15 ° C to 30 ° C. and preferably at a temperature below 25 ° C.

Further examples of the use of prepolymerization for these bis (Cp) metallocene complexes are found in EP 452920, EP 516458, EP 582480 and EP 605952.

WO 94/03506 discloses supported ionic catalysts based on mono (cyclopentadienyl) complexes and ionic activators, which can also optionally be prepolymerized to thereby solidify and enlarge catalyst particles, thereby reducing reactor fouling during polymerization.

WO 94/28034 discloses bridged bis (Cp) metallocene catalysts which reduce the tendency of the catalyst to clog the reactor during polymerization and increase their ability to control the morphology of the final polymer in favor of particles.

WO 966/00243 discloses chiral metallocenes useful for the production of highly isotactic polypropylene copolymers which have been shown to prepolymerize to improve particle morphology.

In all of these systems, the transition metal is found in the metallocene complex either in the +3 oxidation state or more often in the highest oxidation state of +4.

WO 95/00526 describes titanium or zirconium complexes in which the transition metal is present in a formal oxidation

01-2993-99 _e-CE © and © ce ccc © «6 © * • · · 44« 4 »·

state +2. The complex also contains a neutral, conjugated or unconjugated pulp ligand that forms a π-complex with the metal. These complexes are prepared by combining the catalyst with an activating cocatalyst, for example, aluminoxanes, boranes or borates. When used in the gas phase, these catalysts are suitably supported on essential oils. However, there is no mention in this document of possible prepolymerization using these gas phase catalysts.

The aim of prepolymerization in the complexes described above is either to reduce reactor fouling or to improve the morphology of the final polymer, both of which are generally claimed in connection with Ziegler-Natta or chromium systems.

It has now been found that prepolymerization in the presence of transition metal complexes can be used to increase the reactivity of these complexes, especially when used in the gas phase, for example in a stirred dry phase reactor.

In particular, it has been found that the catalytic activity of the gas-phase transition metal catalyst complexes can be increased by using an initial low temperature prepolymerization step (relative to the final polymerization temperature), either in a separate step or in situ prior to the final polymerization step.

SUMMARY OF THE INVENTION

Thus, the invention provides a process for the polymerization of ethylene or copolymerization of ethylene and one or more alpha-olefins in the gas phase, comprising:

(1) in a first stage, prepolymerization of ethylene or ethylene and one or more alpha-olefins in the gas phase at a temperature of 20 to 70 ° C in the presence of a catalyst system comprising (a) a supported transition metal complex; and (b) an activator; (2) optionally isolating the prepolymerized catalyst; and (3) in a second stage polymerizing ethylene or ethylene and one or more alpha-olefins in the gas phase at a temperature of 65 to 100 ° C in the presence of the prepolymerized catalyst.

The invention is particularly suitable for use in a complex with limited geometry.

The term limited geometry complex known to those skilled in the art refers to complexes in which a metal atom is pushed to the more exposed position of the active metal by one or more substituents on a delocalized moiety bound by a π bond. These complexes are described in detail in EP 416815, which is incorporated herein by reference.

The process of the invention may be carried out in a single gas reactor, where both stages may be performed, or the prepolymerized catalyst from the first stage may be isolated prior to use in the final polymerization.

The prepolymerized catalyst can be isolated by conventional means.

The prepolymerization step is most preferably carried out at a temperature of 20 to 65 ° C and most preferably at 25 to 40 ° C, and the final polymerization step is preferably carried out at a temperature of 65 to 100 ° C and most preferably at a temperature of 70 to 85 ° C.

01-2993-99-English «66 • · *

During the prepolymerization step, the pressure generally ranges from 0.01 MPa to 1 MPa. In the final polymerization stage, the pressure is increased and generally ranges from 0.5 to 2 MPa.

The titanium or zirconium complex is particularly suitable as a limited geometry complex in the process of the invention. These complexes are described in the aforementioned WO 95/00526, which is incorporated herein by reference. These complexes have the general formula

wherein each R 'is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, wherein R' has up to 20 non-hydrogen carbon atoms and optionally two R ' groups (in which R 'is not hydrogen, halogen or cyano) together form a bivalent derivative linked to adjacent positions of the cyclopentadienyl ring to form a fused ring structure;

X represents a neutral? ^14- bound marrow group containing up to 30 non-hydrogen atoms, and forms a π-complex with M;

Y represents a hydrogen atom, a sulfur atom, -NR * -, -PR * -;

M represents titanium or zirconium in the formal oxidation state of +2;

01-2993-99-English · · · · ··· ····

Z * represents SiR ₂ , CR * ₂ , SiR * ₂ SiR * ₂ , CR * ₂ CR * ₂ , CR * = CR *, CR ₂ SiR * ₂ or GeR * ₂ ; wherein each R * is independently hydrogen or is selected from hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, wherein R * has a maximum of 10 non-hydrogen atoms and optionally two R * groups from Z * (wherein R * is not hydrogen), or R * is a group of Z * and R * is a group of Y forms a cyclic system.

Most preferred complexes are amidosilane or amidoalkanediyl complexes in which the metal is titanium.

Particularly preferred marrow groups are 1,4-diphenyl-1,3-butadiene, 1,3-pentadiene, 1,4-dibenzyl-1,3-butadiene, and 3-methyl-1,3-pentadiene.

Illustrative but non-limiting examples of preferred complexes are (tert-butylamido) (tetramethyl-H5-cyclopentadienyl) dimethylsilanetitanium (II) 1,1,4-diphenyl-1,3-butadiene, (tert-butylamido) (tetramethyl-H5-cyclopentadienyl) dimethylsilanetitanium (II) -1,3-pentadiene, (tert-butylamido) (2-methyl) dimethylsilanetitanium (11) 1,4-diphenyl-1,3-butadiene.

These complexes can be catalytically activated by combining them with an activating cocatalyst or using an activating technique. Suitable activating cocatalysts for this purpose are, for example, polymeric or oligomeric alumoxanes, in particular methylalumoxanes, triisobutylaluminum modified methylalumoxane or diisobutylalumoxane; strong Lewis acids, for example compounds of the 13th group substituted by a hydrocarbyl group having 1 to 30 carbon atoms, in particular compounds of tri (hydrocarbyl) aluminum or tri (hydrocarbyl) boron and their halogenated derivatives which

01-2993-99-Ce

444 4444 44 444 · 4 4 * have 1 to 10 carbon atoms in each hydrocarbyl or halogenated hydrocarbyl group, in particular perfluorinated tri (aryl) compounds boron and most preferably tris (pentafluorophenyl) boron; non-polymeric inert compatible non-coordinating ion-forming compounds (including use of the compounds under oxidizing conditions); bulk electrolysis and combinations of previous activation cocatalysts and techniques. The foregoing activation cocatalysts and techniques are described in connection with said metal complexes in the aforementioned WO 95/00526.

A particularly preferred activator is tris (pentafluorophenyl) boron. Suitable ion-forming compounds useful as cocatalysts include a cation, which is a Bronsted acid capable of donating a proton and an inert compatible non-coordinating anion A-. Preferred anions are those which contain a single coordination complex comprising a charge-carrying metal or metalloid core, the anion being able to balance the charge of the active catalytic species (metal cation) when the two components are combined. The anion should also be sufficiently unstable to be displaced by olefinic, diolefinic and acetylenically unsaturated compounds or other neutral Lewis bases such as ethers or nitriles. Suitable metals include, but are not limited to, aluminum, gold, and platinum. Suitable metalloids include, but are not limited to, boron, phosphorus, and silicon. Compounds containing anions that contain coordination complexes containing a single metal or metalloid atom are commercially available, with compounds containing one boron atom in the anionic moiety being most preferred.

Preferred boron compounds are salts such as: tetrakis (pentafluorophenyl) borate,

01-2993-99-Ce triethylammoniumtetrakis (pentafluorophenyl) borate, Ν, Ν-dimethylaniliniumtetrakis (pentafluorophenyl) borate and Ν, Ν-diethylaniliniumtetrakis (pentafluorophenyl) borate.

Other limited geometry complexes suitable for use in the process of the invention are those in which the metal is in a higher oxidation state. These complexes are described, for example, in EP 416815 and WO 91/04257, which are incorporated herein by reference. These complexes have the general formula:

(X) in which

Cp * represents a R 5 -cyclopentadienyl or η 5 -substituted cyclopentadienyl group optionally covalently attached to M via -Z-Y-, which group has the general

wherein each R is a hydrogen atom or a group selected from a halogen atom, an alkyl group, an aryl group, a haloalkyl group, an alkoxy group, an aryloxy group, a silyl group, and combinations thereof;

Have a maximum of 20 non-hydrogen atoms, or two or more R groups together form a fused ring system;

M is zirconium, titanium or hafnium bonded in a bonded manner to a cyclopentadienyl group or a substituted cyclopentadienyl group and is in the oxidation state +3 or +4;

Each X represents a hydride or a group selected from the group consisting of halo, alkyl, aryl, silyl, germyl, aryloxy, alkoxy, amide, siloxy, and combinations thereof (e.g., haloalkyl, haloaryl, alkaryl, arylalkyl, silylalkyl, aryloxyaryl and alkyloxyalkyl, amidoalkyl, amidoaryl) having a maximum of 20 non-hydrogen atoms and neutral Lewis base ligands having a maximum of 20 non-hydrogen atoms;

n is 1 or 2 depending on the oxidation state M;

Z represents a bivalent group containing an oxygen atom, a boron atom or a member of the 14th group of the Periodic Table of the Elements;

Y represents a linking group covalently bonded to a metal containing a nitrogen atom, a phosphorus atom, an oxygen atom or a sulfur atom, or optionally Z and Y together form a fused ring system.

The most preferred complexes are those in which Y represents a group containing a nitrogen or phosphorus atom and which corresponds to the general formula (-NR ¹ ) or

01-2993-99-English • ·

(-PR ¹ ) in which R ¹ represents an alkyl group having 1 to 10 carbon atoms, and those complexes in which Z represents SiR ₂ , CR ₂ , SiR ₂ SiR ₂ , CR = CR or GeR ₂ , in which R is hydrogen or hydrocarbyl.

The most preferred complexes are those in which

M is titanium or zirconium.

Illustrative, but not limiting, examples of suitable complexes are (tert-butylamido) (tetramethyl-η 5 cyclopentadienyl) dimethylsilanetitanium dimethyl, (tert-butylamido) dibenzyl (tetramethyl-η 5 -cyclopentadienyl) silanzirconium dimethyl, (tetramethylamido) dimethyl (tert-butylamido) dimethyl (tert-butylamido) dimethyl (phenylphosphido) dimethyl (tetramethyl-β-cyclopentadienyl) silanzirconium dibenzyl and the like.

These complexes are catalytically activated by combining them with activating cocatalysts similar to those described above. Suitable cocatalysts include aluminoxanes, especially methylaluminoxane (MAO) or strong Lewis acids, e.g. boron tri (hydrocarbyl) compounds or halogenated derivatives thereof.

Particularly suitable as activator is tris (pentafluorophenyl) boron.

These complexes can also be activated by the ion forming compounds described above.

The transition metal complex suitable for use in the method of the invention may also be the traditional bis (cyclopentadienyl) transition metal complex described in EP 129368 or EP 206794. These complexes may be represented by the general formula Cp ₂ MX ₂ , wherein M is zirconium,

01-2993-99-Ce

9 '9

9 · 9 9 9

9 9 9 9 9 9 Titanium or hafnium and X represents an anionic ligand. These complexes may advantageously contain cyclopentadienyl rings which are substituted with hydrocarbyl groups, for example an alkyl group. Examples of such complexes are bis (cyclopentadienyl) zirconium dichloride or bis (tetramethylcyclopentadienyl) zirconium dichloride.

Also suitable are transition metal complexes in which the substituents on the cyclopentadienyl rings form a bridge between the two rings, for example those described in EP 659773. A particularly suitable complex is ethylenebis (indenyl) zirconium dichloride.

The bis (cyclopentadienyl) transition metal complexes described above are most suitably activated by alumoxanes and especially methylalumoxane.

Another type of transition metal complex suitable for use in the method of the invention is the bis (cyclopentadienyl) diene complexes described in WO 96/04920, which is incorporated herein by reference.

Such complexes can be represented by the general formula:

R

01-2993-99-English in which

M represents titanium, zirconium oxidation state +2 or +4;

each R 'and R' is independently selected from the group consisting of hydrogen, hydrocarbyl, silyl, germyl, kayno, halo, and combinations thereof, wherein R 'and R each have a maximum of 20 non-hydrogen atoms, or adjacent R * groups and / or R groups (unless all R 'and R are not hydrogen) or adjacent R' groups and / or R groups (unless R ¹ and R are not hydrogen, halo or cyano) together form a bivalent derivative to form a fused ring system);

E represents a silicon atom, a germanium atom or a carbon atom;

x is an integer from 1 to 8;

each R 'independently represents a hydrogen atom or a group selected from the group consisting of silyl, hydrocarbyl, hydrocarbyloxy and combinations thereof, or two R' together form a ring system, wherein R '' has a maximum of 30 carbon or silicon atoms; and

D is a stable conjugated diene optionally substituted with one or more hydrocarbyl groups, silyl groups, hydrocarbylsilyl groups, silyl hydrocarbyl groups, or mixtures thereof, wherein D has from 4 to 40 non-hydrogen atoms.

Particularly suitable are complexes in which M is zirconium and E is carbon.

or hafnium in formal

01-2993-99-English 999 9 9 0 9 9 9 9 9 9 99

999 9 999 * 9 «• 9 9 9 9», 999

These complexes can be cocatalysts. Especially (pentafluorophenyl) boron.

suitably activated by the above-described preferred cocatalyst, the tri-molar ratio of complex to activator used in the process of the invention may range from 1:10,000 to 100: 1. The preferred range is 1: 5,000 to 10: 1, and most preferably 1:10 to 1: 1.

The complexes according to the invention intended for use in the gas phase are deposited on a carrier.

The carrier can generally be any organic or inorganic inert solid, in particular a porous carrier such as talc, inorganic oxides and resinous carrier materials such as polyolefins. Suitable inorganic oxides which can be used are Group 2, 13, 14 or 15 metal oxides of the Periodic Table of the Elements, for example silica, alumina, silico-alimuna and mixtures thereof. Other inorganic oxides that can be used either alone or in combination with silica, alumina or silicoalumina are magnesium oxide, titanium dioxide or zirconia. Other suitable carrier materials that can be used are, for example, finely divided polyolefins, such as polyethylene.

The most preferred support material applicable to supported catalysts used in the process of the invention is silica. Suitable silicas include Crossfield ES70 and Davidson 948.

It is preferred that the silica is dried prior to use, wherein the drying is generally carried out at elevated temperatures, for example at 200 to 850 ° C.

01-2993-99-English β * * * r • • • • • • • • • • • • • • • 4 4 4 4 4 4 4 4 4 • 4,444 44444 · 9444 · 44 4 4,444 4 · 4 »

In a preferred embodiment of the invention, the supported catalyst can be prepared by adding a solution of activator in a suitable solvent to a suspension of activated silica treated with a trialkylaluminum compound and then adding a solution of the transition metal complex in the same solvent. Alternatively, the complex may be added to the silica treated trialkyl aluminum prior to the addition of the activator.

A suitable solvent for the supported catalyst is toluene.

Suitable trialkylaluminum compounds are trimethylaluminum (TMA), triethylaluminum (TEA) or triisobutylaluminum (TIBAL).

Both the first and second stages can be carried out in a dry phase reactor or a dry phase reactor. in a fluidized bed reactor.

Alternatively, the prepolymerized catalyst, when isolated from the first stage, can be used in another gas reactor where the second stage of the process of the invention is carried out.

The most preferred gas reactor for the first stage of the invention is a dry phase reactor, in particular a mixed dry phase reactor (ADPR).

The most preferred process for carrying out the process of the invention in a fluidized bed reactor is described in WO 94/28032. Further processes for carrying out the process in a fluidized bed reactor are described in EP 89691, WO 94/25495 and WO 94/25497.

The invention also provides a process for preparing a prepolymerized catalyst.

01-2993-99-Ce

• 9 · 9 9 9 9 9 · · 9 9 9 9 ·

Φ Φ Φ Φ

Accordingly, another aspect of the invention is to provide a process for preparing a prepolymerized catalyst comprising prepolymerizing ethylene or ethylene and one or more alpha-olefins in the presence of a catalyst system comprising (a) a supported transition metal complex and (b) an activator to form a prepolymerized catalyst; isolating the prepolymerized catalyst.

The invention can also be applied to processes in which the prepolymerization is carried out in suspension phase.

Accordingly, another aspect of the invention is to provide a process for the polymerization of ethylene or ethylene and one or more alpha-olefins, comprising:

(1) in a first step of prepolymerizing ethylene or ethylene and one or more alpha-olefins at a temperature of -20 ° C to + 60 ° C in the presence of a catalyst system comprising (a) a supported transition metal complex and (b) an activator to form a prepolymerized catalyst;

(2) optionally isolating the prepolymerized catalyst;

(3) in a second stage, gas-phase polymerization of ethylene or ethylene and one or more alpha-olefins at a temperature of 65 ° C to 100 ° C in the presence of a prepolymerized catalyst.

The first step can be carried out in a slurry reactor, a stirred dry phase reactor or a fluidized bed reactor.

The prepolymerized catalyst may be isolated prior to the start of the second step or used in situ.

The process according to the invention is suitable for use in the polymerization of olefins, in particular in the homopolymerization of ethylene or copolymerization of ethylene with other alpha-olefins, in particular e e.

01-2993-99-Ce with olefins having 3 to 10 carbon atoms. Most preferred alpha-olefins are 1-butene, 1-hexene and 4-methyl-1-pentene.

Using the process of the invention, polymers can be prepared having a density of 0.905 to 0.960 g / cm ³ and a melt index of 0.1 to 20 as determined by ASTM D1238 under conditions E (2.16 kg at 190 ° C).

The process of the invention will be further illustrated by the following examples. These examples clearly show that the use of the prepolymerization step alone or in situ results in improved efficiency of the catalyst systems.

DETAILED DESCRIPTION OF THE INVENTION

Example 1 - Preparation of Catalyst A g Crosfield ES70 silica (activated at 500 ° C) was suspended in 50 ml of anhydrous hexane. 30 ml of 0.5 M TMA in hexane (1.5 mmol Al / g silica) was added and the suspension was stirred for 2 hours. The treated silica was filtered and washed three times with 20 ml of hexane, then dried under vacuum to a fine powder.

g TMA treated ES70 silicas were suspended in 10 mL of anhydrous hexane. 1.95 ml of 7.85 wt. solution of tris (pentafluorophenyl) boron in toluene and the mixture was shaken vigorously. 0.62 ml of 12.25 wt. of a solution of (tert-butylamido) (tetramethyl-η ⁵ -cyclopentadienyl) dimethylsilanetitanium dimethyl in toluene. The mixture was shaken well and the solvent was removed in vacuo at 20 ° C to give a yellow powder.

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01-2993-99-Ce

Example 2 - Preparation of Catalyst B

7.0 kg of Crosfield ES70 silica (activated at 500 ° C) was suspended in 100 L of anhydrous hexane. Added

9.32 L of 0.976 M TEA in hexane (1.3 mmol Al / g silica) and the suspension was stirred at 30 ° C for 2 hours. The silica was allowed to settle and the hexane supernatant was removed. The silica was further purged with hexane until the Al concentration in the wash was less than 1 mmol Al / L. The silica was then dried under vacuum at 40 ° C.

g TEA treated ES70 silica was suspended in 15 mL of anhydrous hexane. 1.8 ml of 7.85 wt. solution of tris (pentafluorophenyl) boron in toluene and the mixture was shaken vigorously. 0.62 ml of 10.7 wt. of a solution of (tert-butylamido) (tetramethyl-η ⁵ -cyclopentadienyl) -dimethylsilanetitanium penta-1,3-diene in toluene. The mixture was shaken well and the solvent was removed in vacuo at 20 ° C to give an olive green powder.

Example 3 - Preparation of Catalyst Cg The TEA treated ES70 silica described in connection with Catalyst B preparation was suspended in 150 ml of anhydrous toluene. 10.4 ml of 10.7 wt. of a solution of (tert -butylamido) (tetramethyl-η ⁵ -cyclopentadienyl) dimethylsilanetitaniumpenta-1,3-diene in toluene and the mixture was shaken vigorously. Then 29.4 ml of 7.85 wt. of a solution of tris (pentafluorophenyl) boron in toluene. The mixture was shaken well and after being stripped of the solvent under vacuum at 40 ° C gave an olive green powder.

e e ee • ·

01-2993-99-Ce

Example 4 - Preparation of Catalyst D g TEA treated ES70 silica described in connection with Catalyst B preparation was suspended in 50 ml of anhydrous toluene. 2.1 ml of 10.7 wt. of a solution of (t-butylamido) (tetramethyl-η ⁵ -cyclopentadienyl) -dimethylsilanetitanium penta-1,3-diene in toluene and the mixture was shaken vigorously. Then 5.9 ml of 7.85 wt. of a solution of tris (pentafluorophenyl) boron in toluene. The mixture was shaken well and after being stripped of the solvent under vacuum at 20 ° C gave an olive green powder.

Example 5 - Preparation of Catalyst E

45.76 g of TEA-treated ES70 silica described for the preparation of Catalyst B was suspended in 225 ml of anhydrous toluene. 9.51 ml of 10.7 wt. of a solution of (t-butylamido) (tetramethyl-β ⁵ -cyclopenta-dienyl) dimethylsilanetitaniumpenta-1,3-diene in toluene and the mixture was shaken well. Then 26.9 ml of 7.85 wt. of a solution of tris (pentafluorophenyl) boron in toluene. The mixture was shaken well and after being stripped of the solvent under vacuum at 20 ° C gave an olive green powder.

Example 6 - Preparation of Catalyst C prepolymer

A 2.5 L dry phase stirred reactor was fired at 85 ° C with nitrogen purge. It was then cooled to 25 ° C and charged with 44.41 g of catalyst C. The reactor was then pressurized to 0.047 MPa with nitrogen. The catalyst was stirred at 300 min ^-1. Pressure that

The addition of ethylene increased to 0.030 MPa, rapidly reduced to 0.080 MPa in order to keep the reactor temperature below 40 ° C. This was continued for 126 minutes. Then 34.0 g of polymer-coated catalyst was isolated from the reactor under nitrogen. The polymer yield was 0.5 g PE / g catalyst.

Example 7 - Preparation of Catalyst E Prepolymer

A 2.5 L dry phase stirred reactor was fired at 85 ° C with nitrogen purge. It was then cooled to 25 ° C and charged with 46.3 g of catalyst E. The reactor was then pressurized with nitrogen to 0.105 MPa. The catalyst was stirred speed of 325 min ^-1. The pressure was increased to 0.125 MPa by adding ethylene. These conditions were maintained

3.75 hours. The reactor was then purged with nitrogen at 50 psi and left overnight for 16 hours.

Ethylene was again added to the reactor, which increased the reactor pressure to 0.125 MPa. 50 minutes after the start, the pressure increased to 0.130 MPa and 5 hours after the start, the pressure increased to 0.142 MPa. After 6 hours of polymerization, the reactor was purged with nitrogen and 68.1 g of polymer-coated catalyst was isolated under nitrogen. The polymer yield was 2.0 g PE / g catalyst.

Example 8 - In-situ prepolymerization of Catalyst A

285 g of sodium chloride was added to the stirred dry phase reactor after firing at 85 ° C under nitrogen purge. 1.67 g of TEA-treated silica was added to the reactor, which was stirred for 15 minutes. The temperature was reduced to 30 ° C and ethylene was added to the reactor to adjust the pressure

01-2993-99-English »··· ·······

in a reactor at 0.7 MPa. A mixture of 0.22 g of catalyst A and 1.04 g of TEA-treated silica was then injected into the reactor under high nitrogen pressure. The ethylene pressure was maintained at 0.7 MPa and the temperature was rapidly raised to 80 ° C. This temperature was maintained until the end of the test. The total polymerization time was 120 minutes. The reactor was vented and cooled, and 127 g of polymer giving 41 g / g.h.bar was isolated.

Comparative Example 1

In this comparative example, a procedure similar to Example 8 was followed except that the initial 30 minute period at 30 ° C was omitted. A mixture of 0.243 g of catalyst A and 0.935 g of TEA-treated silica was injected into the reactor at 70 ° C, whereupon the temperature was immediately raised to 80 ° C. The reaction was allowed to proceed for 100 minutes. 64 g of polymer having a catalytic activity of 20.5 g / g.h.bar were isolated.

Comparison of Example 8 with Comparative Example 1 showed that in-situ prepolymerization in a stirred dry phase reactor resulted in an increase in the homopolymerization activity of the catalyst.

Example 9 - In-situ prepolymerization of Catalyst B

320 grams of sodium chloride was added to a 2.51 L stirred dry phase reactor, which had been pre-fired with a nitrogen purge at 85 ° C. Subsequently, 1.25 g of TIBAL-treated silica was added to the reactor and stirred for 15 minutes. The temperature was lowered to 30 ° C and ethylene was added to the reactor to raise the reactor pressure to 1 bar. Then do

01-2993-99-Ce

0.308 g of catalyst B and 0.825 g of TIBAL-treated silica were injected into the reactor under high nitrogen pressure. The ethylene pressure was maintained for about 5 minutes at 0.1 MPa, whereupon it rose sharply to 0.65 MPa and the temperature rapidly increased to 70 ° C. Hydrogen and hydrogen were then introduced into the reactor

1-hexene. The temperature, the ethylene pressure and the hydrogen and 1-hexene concentrations were kept constant until the end of the test. The total polymerization time was 191 minutes. During the test, the average ratio of hydrogen to ethylene was 0.0046 and the average ratio of 1-hexene to ethylene was 0.0052. The reactor was vented and cooled, and 278 g of polymer having a catalytic activity of 43.6 g / ghbar was isolated. Melting index. The MI _{2 16} was 7.41 and the density 0.926 g / ml.

Example 10 - In-situ prepolymerization of Catalyst B

288 g of sodium chloride was added to a 2.51 L stirred dry phase reactor, which had been pre-fired under a nitrogen purge at 85 ° C. Subsequently, 1.30 g of TIBAL-treated silica was added to the reactor and stirred for 15 minutes. The temperature was lowered to 30 ° C and ethylene was added to the reactor to raise the reactor pressure to 1 bar. 0.238 g of catalyst B and 0.725 g of TIBAL-treated silica were then injected into the reactor under high nitrogen pressure. The ethylene pressure was maintained at about 1 bar for about 5 minutes, then rapidly increased to about 600 bar and the temperature rapidly increased to about 80 ° C. Then hydrogen and 1-hexene were fed to the reactor. The temperature, the ethylene pressure and the hydrogen and 1-hexene concentrations were kept constant until the end of the test. The total polymerization time was 116 minutes. During the test, the average ratio of hydrogen to ethylene was 0.0052 and the average ratio of 1-hexene to ethylene was 0.0049. Reactor se

01-2993-99-C ee was vented and cooled, and 99 g of polymer having a catalytic activity of 33.1 g / ghbar was isolated. The melt index MI _{2 16} was 2.7 and the density 0.9185 g / ml.

Example 11 - In-situ prepolymerization of Catalyst B

To a 2.51 L stirred dry phase reactor, which had been pre-fired under a nitrogen purge at 85 ° C, was added 305 g of sodium chloride. 1.20 g of TIBAL-treated silica was then added to the reactor and stirred for 15 minutes. The temperature was lowered to 30 ° C and ethylene was added to the reactor to raise the reactor pressure to 1 bar. Then 0.231 g of catalyst B and 0.912 g of TIBAL-treated silica were injected into the reactor under high nitrogen pressure. The ethylene pressure was maintained for about 5 minutes at 0.1 MPa, whereupon it rose sharply to 0.65 MPa and the temperature rapidly increased to 70 ° C. Then hydrogen and 1-hexene were fed to the reactor. The temperature, the ethylene pressure and the hydrogen and 1-hexene concentrations were kept constant until the end of the test. The total polymerization time was 189 minutes. During the test, the average hydrogen to ethylene ratio was 0.00395 and

average ratio of 1-hexene to ethylene was 0.0048. Reactor se vented and cooled and isolated se 168 g Polymer s catalytic activity was 1.7 and density 0.9295 35.5 g / g.h. g / ml. bar. Fusible index MI ₂ i ₆

Comparative Example 2

In this example, a similar procedure to Examples 9, 10 and 11 was used except that the initial temperature and pressure settings were omitted. Thus, 344 g of NaCl were added

01-2993-99-English • ·

was added to a 2.51 stirred dry phase reactor which had been pre-fired under a nitrogen purge at 85 ° C. 1.30 g of TIBAL-treated silica was added to the reactor and stirred for 15 minutes. The reactor was cooled to 70 ° C and pressurized to 0.65 MPa with ethylene. Then hydrogen and 1-hexene were fed to the reactor. A mixture of 0.213 g of catalyst C and 0.781 g of TIBAL-treated silica was injected into the reactor under high nitrogen pressure. The temperature, ethylene, pressure and concentrations of hydrogen and 1-hexene were kept constant until the end of the test. The total polymerization time was 166 minutes. During the test, the average hydrogen to ethylene ratio was 0.0038 and the average 1-hexene to ethylene ratio was 0.0053. The reactor was vented and cooled, and 101 g of polymer having a catalytic activity of 26.3 g / g.h.bar was isolated.

Comparison of Examples 9, 10 and 11 with Comparative Example 2 showed that in situ in-situ prepolymerization in a stirred dry phase reactor increased copolymerization catalyst activity.

Example 12 - Polymerization with Catalyst C prepolymer

To a stirred 2.51 dry phase reactor, which was pre-fired with nitrogen introduction at 85 ° C, was added 305 g of sodium chloride. 1.225 g of TIBAL-treated silica was added to the reactor and stirred for 15 minutes. Then the reactor was cooled to 70 ° C and pressurized with ethylene to 0.65 MPa. Hydrogen and 1-hexene were introduced into the reactor. A mixture of 0.956 g of catalyst C prepolymer and 0.745 g of TIBAL-treated silica was injected into the reactor under high nitrogen pressure. The temperature, the ethylene pressure and the hydrogen and 1-hexene concentrations were kept constant until the end of the test. The total polymerization time reached 127 minutes. During

The average hydrogen to ethylene ratio was 0.00415 and the average 1-hexene to ethylene ratio was 0.0057. The reactor was vented, cooled, and 250 g of polymer having an activity of 28.8 g / g.h.bar, based on the weight of the starting catalyst, was isolated.

Example 13 - polymerization with catalyst E prepolymer

To a stirred 2.51 dry phase reactor, which had been pre-fired while introducing nitrogen at 85 ° C, was added 292 g of sodium chloride. 1.223 g of TIBAL-treated silica was added to the reactor and stirred for 15 minutes. Then the reactor was cooled to 70 ° C and pressurized with ethylene to 0.65 MPa. Hydrogen and 1-hexene were introduced into the reactor. Then, a mixture of 1.02 g of catalyst E prepolymer and 0.744 g of TIBAL-treated silica was injected into the reactor under high nitrogen pressure. The temperature, the ethylene pressure and the hydrogen and 1-hexene concentrations were kept constant until the end of the test. The total polymerization time reached 127 minutes. During the test, the average hydrogen to ethylene ratio was 0.0044 and the average 1-hexene to ethylene ratio was 0.0048. The reactor was vented, cooled, and 175 g of polymer having an activity of 37.4 g / g.h.bar, based on the weight of the starting catalyst, was isolated.

Example 14 - Polymerization with Catalyst E prepolymer

To a stirred 2.51 dry phase reactor, which had been pre-fired while introducing nitrogen at 85 ° C, was added 352 g of sodium chloride. The reactor was added

1.20 g of TIBAL-treated silica and the reactor was stirred for 15 minutes.

01-2993-99-English · ···· ee e «• · · ♦ ·.

* '··· · · · ·

Then the reactor was cooled to 70 ° C and pressurized with ethylene to 0.65 MPa. Hydrogen and 1-hexene were introduced into the reactor. A mixture of 0.915 g of catalyst E prepolymer and 0.8 g of TIBAL-treated silica was injected into the reactor under high nitrogen pressure. The temperature, the ethylene pressure and the hydrogen and 1-hexene concentrations were kept constant until the end of the test. The total polymerization time was 87 minutes. During

test was average ratio hydrogen ku ethylene 0.0044 a the average ratio of 1-hexene to ethylene was 0.0055. Reactor se vented, chilled and isolated se 128 g of polymer s activity 44.5 g / g.h . bar, relative weight default

of the catalyst.

Examples 13 and 14 and Comparative Example 2 are based on the same starting base catalytic formulation (see above). These examples show that prepolymerization of the catalyst prior to injection into the reactor results in increased catalyst activity.

01-2993-99-Ce

Claims (20)

(1) in a first step of prepolymerizing ethylene or ethylene and one or more alpha-olefins at a temperature of -20 ° C to + 60 ° C in the presence of a catalyst system comprising (a) a supported transition metal complex and (b) an activator to form a prepolymerized catalyst; 01-2993-99-English • ee β e e e e e e e e e e e e e e e e e e e e »· ·· 01-2993-99-Eng ···· »« e e e e 01-2993-99-English. **. Silylalkyl, aryloxyaryl and alkyloxyalkyl, amidoalkyl, amidoaryl) having a maximum of 20 non-hydrogen atoms and neutral Lewis base ligands having a maximum of 20 non-hydrogen atoms ; n is 1 or 2 depending on the oxidation state M; Z represents a bivalent group containing an oxygen atom, a boron atom or a member of the 14th group of the Periodic Table of the Elements; Y represents a linking group covalently bonded to a metal containing a nitrogen atom, a phosphorus atom, an oxygen atom or a sulfur atom, or optionally Z and Y together form a fused ring system. 01-2993-99-English · · · · · · · · · · · · · · · · · · · · · · · · · · · · Cp * represents a single H5-cyclopentadienyl or η5substituted cyclopentadienyl group optionally covalently attached to M via -Z-Y-, which group has the general formula: wherein each R is a hydrogen atom or a group selected from halogen, alkyl, aryl, haloalkyl, alkoxy, aryloxy, silyl, and combinations thereof having up to 20 non-hydrogen atoms, or two or more R groups taken together form condensed ring system; M is zirconium, titanium or hafnium bonded in a bonded manner to a cyclopentadienyl group or a substituted cyclopentadienyl group and is in the oxidation state +3 or +4; Each X is a hydride or a group selected from the group consisting of halo, alkyl, aryl, silyl, germyl, aryloxy, alkoxy, amide, siloxy, and combinations thereof (e.g., haloalkyl, haloaryl, halosilyl, alkaryl, alkaryl, alkaryl, alkaryl, alkaryl, alkaryl, alkaryl, alkaryl, alkaryl, alkaryl, an aralalkyl group, 01-2993-99-English • ··· 01-2993-99-English * · • ··· ♦ · (1) in the first stage, prepolymerization of ethylene or ethylene and one or more alpha-olefins in the gas phase at a temperature of 20 to 70 ° C in the presence of a catalyst system comprising (a) a supported transition metal complex and (b) an activator; and (3) in a second step, gas-phase polymerization of ethylene or ethylene and one or more alpha-olefins at a temperature of 65 to 100 ° C in the presence of the prepolymerized catalyst. A process for the polymerization of ethylene or a copolymerization of ethylene and one or more alpha-olefins in the gas phase, comprising: (2) optionally isolating the prepolymerized catalyst; Process according to Claim 1, characterized in that the first step is carried out at a temperature of 25 to 40 ° C and the second step is carried out at a temperature of 70 to 85 ° C. (3) in a second stage, gas-phase polymerization of ethylene or ethylene and one or more alpha-olefins at a temperature of 65 ° C to 100 ° C in the presence of a prepolymerized catalyst. Method according to claim 1 or 2, characterized in that the first stage is carried out at a pressure of 0.01 MPa to 1 MPa. Method according to one of the preceding claims, characterized in that the first stage is carried out in the dry phase. 5. The process according to claim 4, wherein the first stage is carried out in a stirred dry phase reactor. Process according to one of the preceding claims, characterized in that the two stages are carried out in a single gas phase reactor. A process according to any one of the preceding claims wherein the transition metal complex is a complex with limited geometry of the general formula wherein each R 'is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, wherein R 'has up to 20 non-hydrogen carbon atoms and optionally two R' groups (wherein R 'is not hydrogen, halo or cyano) together form a bivalent derivative linked to adjacent positions. 8. The process of claim 7 wherein the complex is (tert-butylamido) (tetramethyl-H5-cyclopentadienyl) dimethylsilanetitanium (II) 1,3-pentadiene. team The method of claims 1 to 6, wherein the transition metal complex has the general formula A cyclopentadienyl ring and forms a cyclic structure; so condensed X is neutral T1 ^{A 4-} linked pith group containing up to 30 non-hydrogen atoms, and forms a π-complex with M; Y represents a hydrogen atom, a sulfur atom, -NR * -, -PR * -; M represents titanium or zirconium in the formal oxidation state of +2; Z * represents SiR ₂ , CR * ₂ , SiR * ₂ SiR * ₂ , CR * ₂ CR * ₂ ,. CR * = CR *, CR ₂ SiR * ₂ or GeR * ₂ ; wherein each R * is independently hydrogen or is selected from hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, wherein R * has a maximum of 10 non-hydrogen atoms and optionally two R * groups from Z * (wherein R * is not hydrogen), or R * is a group of Z * and R * is a group of Y forms a cyclic system. 9 9 ♦ 9 10. The process of claim 9 wherein the complex is (tert-butylamido) (tetramethyl- ^5- cyclopentadienyl) dimethylsilanetitanium dimethyl. Method according to any one of the preceding examples, characterized in that the complex is supported on essential oil. 12. The process of claim 11 wherein the silica is pretreated with a trialkylaluminum compound. Process according to any one of the preceding claims, characterized in that the activator is tris (pentafluorophenyl) boron. Process according to any one of the preceding claims, characterized in that the ratio of complex to activator ranges from 1:10 000 to 100: 1. Method according to any one of the preceding claims, characterized in that the ratio of complex to activator ranges from 1:10 to 1: 1. 16. A process for preparing a prepolymerized catalyst comprising prepolymerizing ethylene or ethylene and one or more of the presence of an alpha-olefin catalyst system comprising (a) a supported transition metal complex and (b) an activator to form a prepolymerized prepolymer catalyst. subsequent isolation by The method according to claim 16, wherein it is carried out in the dry phase. marked 18. A process for the polymerization of ethylene or ethylene and one or more alpha-olefins, characterized in that it comprises: Process according to claim 18, characterized in that the first step is carried out in suspension, in the dry phase or in the gas phase. Process according to one of the preceding claims, characterized in that the alpha-olefins are 1-butene, 1-hexene or 4-methyl-1-pentene.