WO2000044795A1

WO2000044795A1 - A high activity olefin polymerization procatalyst, its preparation, catalyst system and use

Info

Publication number: WO2000044795A1
Application number: PCT/FI2000/000048
Authority: WO
Inventors: Ulf Palmqvist; Solveig Johansson; Daniel Lindgren; Ove Andell; Jarmo Lindroos
Original assignee: Borealis Polymers Oy; Borealis Technology Oy
Current assignee: Borealis Polymers Oy; Borealis Technology Oy
Priority date: 1999-01-26
Filing date: 2000-01-25
Publication date: 2000-08-03
Anticipated expiration: 2001-07-26
Also published as: AU2297700A; WO2000044795A8; FI990140A0

Abstract

The invention relates to a high activity procatalyst for the polymerization of C2-C10 olefins, as well as a process for the preparation of this catalyst. The procatalyst has low hydrogen sensitivity and high polymerization activity and give homogenous C2-C10 olefin polymers. The procatalyst is prepared by contacting (a) an inorganic support, (b) an aluminium compound containing both an organic group and chlorine, (c) a compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, (d) a titanium compound, typically a titanium chloride, and (e) a chlorine compound, which is either the same or different from the organic aluminum chloride compound.

Description

A high activity olefin polymerization procatalyst, its preparation, catalyst system and use

The invention relates to a high activity procatalyst for the polymerization of C₂-C₁₀ olefins. The procatalyst has been prepared by contacting (a) an inorganic support, (b) an aluminium compound of the formula (1):

(R_3-nAlCl_n)_m (1)

wherein R is a C C₂o hydrocarbyl group or a Cι-C₂₀ hydrocarbyloxy group, n is 1 or 2, and m is 1 or 2, (c) a compound or mixture containing hydrocarbyl and hydro- carbyl oxide linked to magnesium, and (d) a titanium compound having the formula (2):

(OR')₄-χTiCl_x (2)

wherein R' is a C₂-C₂o hydrocarbyl group and x is an integer from 0 to 4.

The invention also relates to a catalyst system for the polymerization of C₂-C₁₀ olefins, comprising said procatalyst and a separate cocatalyst. The cocatalyst is an organometallic compound based on a metal selected from Groups 1 to 3 and 13 of the Periodic Table of the Elements (IUPAC 1990).

Further, the invention relates to a process for the preparation of a high activity procatalyst for the polymerization of C₂-C₁₀ olefins, which has been prepared by contacting the above mentioned inorganic support, aluminium compound, compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, and titanium compound.

Finally, the invention relates to a process for the polymerization of C₂-C₁₀ olefins in which at least one C₂-C_lυ olefm is under polymerization conditions contacted with said procatalyst, and a separate cocatalyst which is an organometallic compound based on a metal selected from Groups 1 to 3 and 13 of the Periodic Table of the Elements (IUPAC 1990).

C₂-C₁₀ olefins alone or with other unsaturated monomers can often be polymerized in the presence of a catalyst composition, which has essentially two components: a compound of a transition metal belonging to groups 4 to 6 of the Periodic Table of

Elements (IUPAC 1990) which is often called a procatalyst, and an organometallic compound of a metal belonging to any of groups 1 to 3 and 13 of said Table which is the s.c. cocatalyst. This kind of Ziegler-Natta catalyst composition has been further developed by depositing the procatalyst on a more or less inert and particulate support and by adding to the catalyst composition in the stages of its preparation several additives, among others electron donating compounds. These compounds have improved the polymerization activity of the catalyst, the operating life and other properties of the catalyst composition and first of all the properties of the polymers which are obtained by means of the catalyst composition.

A procatalyst is disclosed in European patent 688 794, by which C2-C10 olefin homopolymers or copolymers having low or high molecular weight can be produced with an even and high activity. Independently of the amount of hydrogen introduced into the polymerization reactor, a balance of the activities can in both cases be achieved by using said procatalyst. It is thus possible to carry out an ethylene polymerization by the use of this catalyst to achieve resins at high and low melt flow rate and still have very similar high productivity.

However, certain poly-C₂-C₁o olefins such as some bimodal resins having a very broad molecular weight distribution prepared by the catalyst system described by European patent 688794 are inhomogenous. Even after compounding, the resins have an unacceptably high degree of inhomogeneity, which appears as white dots in black pipes, or as gels in films, prepared from the resins. The inhomogeneity problem is not specific to a catalyst prepared according to EP 688 794 only, but is a very typical feature for most of the existing catalysts. There are examples of catalysts which are capable of producing bimodal resins having a good homogeneity, like the one disclosed in FI 980788. However, they are more an exception than a rule.

The purpose of the invention is thus to provide a procatalyst and catalyst system, which produces poly-C₂-C₁₀ olefins in high yield and independently of which molecular weight is aimed at. Further, a procatalyst and catalyst system is strived for, which produces a homogenous poly-C₂-C₁₀ olefin product, which does not give e.g. white dots when processed into black pipes, nor gels when processed into film. Finally, a polymerization process is aimed at, which produces poly-C₂-C₁o olefins, which are processable into homogenous polymer products such as pipes and films.

These aims of the invention have now been achieved by means of a novel high activity procatalyst for the polymerization of C₂-C₁₀ olefins, which procatalyst has been prepared by contacting (a) an inorganic support, (b) an aluminium compound of the formula (1):

(R_3-nAlCl_n)_m (1)

wherein R is a C C₂o hydrocarbyl group or a C*ι-C₂o hydrocarbyloxy group, n is 1 or 2, and m is 1 or 2, (c) a compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, and (d) a titanium compound having the formula (2)

(OR')₄-χTiCl_x (2)

wherein R' is a C₂-C₂₀ hydrocarbyl group and x is an integer from 0 to 4. The procatalyst is characterized by further contacting in the preparation thereof, (e) a chlorine compound which is either the same or different from said aluminium compound and said titanium compound and is selected from HC1, Cl₂ or a compound having the formula (3)

R'_q-_pMCl_p (3)

wherein each R' is selected from a hydrogen atom, a -C₂₀ hydrocarbyl group and a CrC₂₀ hydrocarbyloxy group or a pair of R' may form a double-bonded oxygen, M is a non-titanium element selected from Groups 3-16 of the Periodic Table of the Elements (IUPAC 1990), q is the oxidation state of the element M, and p is a number from 1 to q.

The order of contacting the inorganic support, the aluminium compound, the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, the titanium compound and the chlorine compound may be any order which gives a procatalyst having the above mentioned desired properties. However, it is preferable to contact said inorganic support with said aluminium compound to give a first reaction product. Further, it is suitable that said first reaction product is contacted with said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium to give a second reaction product. Still further, it is suitable that said second reaction product is contacted with said chlorine compound to give a third reaction product, and that said third reaction product is reacted with said titanium compound to give a fourth reaction product.

Typically, the claimed procatalyst is prepared by contacting said inorganic support and said aluminium compound to give a first reaction product, by contacting said first reaction product and said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium to give a second reaction product, then by contacting said second reaction product and said chlorine compound to give a third reaction product, and finally, by contacting said third reaction product with said titanium compound to give a fourth reaction product, which is recovered as said procatalyst.

It has been realized, that by adding a further chlorination step when preparing a procatalyst for the polymerization of C₂-C₁₀ olefins, procatalysts are obtained which give more homogenous poly-C -C_lυ olefins. When selecting suitable chlorine compounds for the chlorination step, preferably chlorine compounds are selected, which increase the molar ratios Cl/Al and Cl/Ti of the procatalyst.

The chlorine compound used in the preparation of the claimed procatalyst is either the same or different from the said aluminium compound, which is a hydrocarbyl or hydrocarbyloxyaluminium chloride. It is not said titanium compound, which is a chlorine compound of titanium. According to one embodiment of the invention, the chlorine compound is Cl₂ or HC1. According to another embodiment of the invention, it is a halogen compound of an element selected from Groups 13 and 14 of the Periodic Table of the Elements (IUPAC 1990), such as B(0C₂H₅)C1₂, BC1₃, A1C1₃, GaCl₃, CH₃CI, C₂H₅C1, C₂H₄C1₂, CH₂C1₂, CHC1₃, CCI₄, Si(OC₂H₅)₃Cl, Si(OC₄H₉)₂Cl₂, C₂H₄SiCl₃, SiC-₄, Ge(OC₃H₇)₃Cl, Ge(OC₂H₅)₂Cl₂, Ge(OCH₃)Cl₃, GeC , SnCl₂, SnC , PbCL*. It can also be a non-titanium halide of an element selected from Group 4 of the Table of the Elements such as ZrCl-i and Zr(OC₂H₅)₂Cl₂. According to still another embodiment of the invention it is an organic cMorine-containing compound or a sulphur containing compound, like COCl₂, (COCl)₂, C₆H₅C0C1, SOCl₂, S0₂C1₂, C_nH_2n+1COCl, where n=l-12, i.e. CH₃COCI and C₂H₅C0C1 or a chlorinated hydrocarbon, like tert-butylchloride.

Further, it may be a metal chloride, like A1C1₃, TiC , SbCl₅ and CuCl₂. It may also be vanadium oxytrichloride or vanadium tetrachloride.

It may also be a chlorine containing compound of phosphorous, like phosphorous pentachloride or phosphorous oxide trichloride.

According to one embodiment of the invention, the chlorine compound used in the preparation of the claimed procatalyst is a chlorine compound in gaseous form. Preferably, the chlorine compound is selected from Cl₂, HC1 and BC1₃. Most preferably, the chlorine compound is BC1₃ or HC1. The compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium may be any suitable mixture containing one or more magnesium compound. One of the purposes of the invention is to obtain a high activity procatalyst despite high hydrogen concentrations. The magnesium component of the procatalyst can have both Mg-C bonds and Mg-O-C bonds. These bonds may be in the same magnesium compound such as RMgOR, or in different magnesium compounds. Thus mixtures of R₂Mg and Mg(OR)₂ are within the scope of the invention, as well as mixtures of R₂Mg and RMgOR and mixtures of RMgOR and Mg(OR)₂. Preferably, the compound or mixture containing hydrocarbyl and hydro- carbyl oxide linked to magnesium is hydrocarbon soluble, which gives a solution capable of effectively penetrating the voids and pores of the support.

According to one embodiment of the present invention, said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is a contact product of a di-CrC₁₀ alkyl magnesium and a C C₁₂ alcohol. Preferably, the di-C Cio alkyl magnesium is dibutyl magnesium, butyl ethyl magnesium, diethyl magnesium or butyl octyl magnesium. Preferably, the C₁-C₁₂ alcohol is a branched alcohol, preferably a 2-alkyl alkanol, most preferably 2-ethyl-l-hexanol or 2- ethyl- 1 -pentanol.

When the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is a contact product of a di-CrC₁₀ alkyl magnesium and a Ci- C₁₂ alcohol, the corresponding molar ratio di-Cι-C₁₀ alkyl magnesium to C1-C12 alcohol is preferably 1:1.3 - 1:2.2, more preferably 1: 1.78 - 1:1.99, most preferably 1:1.80 - 1:1.98.

In the case, where the claimed procatalyst is prepared by contacting the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium with said first reaction product, the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is preferably in a nonpolar hydrocarbon solution, most preferably in a nonpolar hydrocarbon solution, the viscosity of which is below 10 mPa-s. Thus, thorough penetration of the magnesium component into the voids and pores of the support is attained. This improves the morphology of the procatalyst and thus the morphology of the poly-C₂-C₁₀ olefins prepared by it, as well.

When contacting the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, good deposition on the surface of the support, which may or may not be prereacted, is obtained if the volume of solution comprising the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is about two times the pore volume of the support material. This is achieved if the concentration of the complex in the hydrocarbon solvent is 5-60% with respect to the hydrocarbon used as solvent. The solvent may be a C₅-C₈ alkane and/or an aromatic C₆-Cι₂ hydrocarbon, e.g. a mixture of a major amount of pentane, hexane or heptane and a minor amount of e.g. toluene.

The inorganic support used in the invention is any support which has the proper chemical and physical properties to act as a support for the active component of the claimed procatalyst. The support material preferably has a suitable average particle size and particle size distribution, a high porosity and a large specific surface area. Especially good results are obtained if the support material has a specific surface area of between 100 and 1000 m²/g support and a pore volume of 1-3 ml/g support. The support material can optionally be chemically pretreated, e.g. by silylation or by treatment with aluminium alkyls.

According to a preferable embodiment of the invention, the inorganic support is a mono-oxide or mixed oxide of an element selected from Groups 3-6 and 13-14 of the Periodic Table of the Elements (IUPAC 1990), preferably a mono-oxide or mixed oxide of silicon, aluminium, titanium, chromium and/or zirconium. More preferably, the inorganic support is a mono-oxide or mixed oxide of silicon and/or aluminium, most preferably silica.

Usually, the support ought to be dried before impregnating it with other catalyst components. Further, the amount of hydroxyl groups which occurs on the surface of most inorganic oxides may be reduced by heat-treatment and/or chemical treatment. Good results are e.g. achieved by treating the support with heat at 100-900 °C, preferably 400-800 °C, for a sufficient time to reduce the hydroxyl groups on the surface to a lower level, which preferably is at the most 2.0 mmol of hydroxyl groups/g of support.

As was said above, when preparing the procatalyst according to the invention, an aluminium compound is used. The aluminium compound contains both an organic group, chlorine and aluminium, whereby it is assumed that it both chlorinates the surface of the support and partly acts as a cocatalyst precursor. However, it is not intended as a cocatalyst, but the claimed catalyst system presupposes large amounts of a separate cocatalyst, see below. The aluminium compound which is contacted in the invention is preferably ethyl aluminium dichloride or ethyl aluminium sesqui- chloride, most preferably ethyl aluminium dichloride. It is recommendable to contact the aluminium compound directly or indirectly with the support in the form of a solution which penetrates the pores of the support and reacts with as many of the surface groups or earlier deposited reagent molecules as possible. Thus, according to one embodiment, said aluminium compound is contacted with said inorganic support so that the aluminium compound is in hydrocarbon solution, preferably in a 5-25 w-% hydrocarbon solution, the viscosity of which most preferably is below 10 mPa-s. Suitable solvents are C₅-Cg alkanes such as pentane, hexane and heptane.

When contacting the aluminium compound with an inorganic support having surface hydroxyl groups, such as silica, the molar ratio between the aluminium compound and the surface hydroxyls of the inorganic support is preferably between 1 and 4. The preferred contacting temperature is between 0 and 110 °C.

One of the main catalyst components is the titanium compound, which is assumed to form the active center during the polymerization of the C₂-C₁₀ olefins. Typical useful titanium compounds are the mixed alkoxy chlorides and chlorides of tetra- valent titanium. The most preferable titanium compound is titanium tetrachloride.

The amount of support, aluminium compound, compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, titanium compound and chlorine compound used in the preparation of the claimed procatalyst may be varied and optimized in order to obtain the best results possible. However, the following amounts are preferable.

In the preparation of the claimed procatalyst, the molar ratio between said chlorine compound and said aluminum compound is preferably 1:0.5 - 1:50, preferably 1: 1 - 1: 10, most preferably 1:2 - 1:4. The molar ratio between said chlorine compound and said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, calculated as magnesium, is preferably 1:0.5 - 1:50, more preferably 1: 1 - 1: 10, most preferably 1:2 - 1:5. The molar ratio between said titanium compound and said aluminium compound, measured as Ti/Al, is preferably 1:1 - 1: 10, more preferably 1: 1 - 1:5, most preferably 1J - 1:3. The amount of said aluminium compound relative to the mass of the inorganic support, measured as mmol Al/g, is preferably 0.01 - 100 mmol/g, more preferably 0.1 - 10 mmol/g, most preferably 0.5 - 3.0 mmol/g. The procatalyst may be washed after any state of the synthesis, using methods known in the art, such as filtering or decanting. Thus, a wash stage may be performed after the chlorination treatment, after the titanation treatment and/or as a last step of the synthesis. Inert hydrocarbons, such as pentane, hexane or heptane, may be used as wash liquids.

In addition to the above described procatalyst for the polymerization of C₂-C10 olefins, the invention also relates to a corresponding catalyst system. The catalyst system comprises a procatalyst as described above, and a separate cocatalyst which is an organometallic compound based on a metal selected from Groups 1 to 3 and 13 of the Periodic Table of the Elements (IUPAC 1990). Preferably, the cocatalyst is a tri-CpC_to alkyl aluminium or a - o alkyl aluminium chloride, preferably a tri-Ci- o alkyl aluminium, more preferably a tri-C₂-C alkyl aluminium, most preferably triethyl aluminium.

In the C₂-C₁₀ olefin polymerization catalyst system according to the present invention, the molar ratio between the aluminium of said cocatalyst and the titanium of said procatalyst is preferably 1: 1 - 100: 1, more preferably 2: 1 - 50: 1 and most preferably 3: 1 - 20: 1.

The invention also relates to a process for the preparation of said high activity procatalyst for the polymerization of C₂-C₁₀ olefins. The procatalyst has, as is the case with most Ziegler-Natta procatalysts, been defined by the process of its preparation. This is because the exact chemical structure of the procatalyst is not known, but only the process which leads to the procatalyst having the desired properties. Therefore, the claimed process for the preparation of said high activity procatalyst has the same technical features as the process described above in connection with the claimed procatalyst.

Last but not least, the invention relates to a process for the polymerization of C₂-C₁0 olefins. In the polymerization process, at least one C₂-C₁₀ olefin is under polymerization conditions contacted with a procatalyst according to the above description, and a separate cocatalyst which is an organometallic compound based on a metal selected from Groups 1 to 3 and 13 of the Periodic Table of the Elements (IUPAC 1990).

The procatalyst, i.e. the transition metal catalyst component of the polymerization process, has the same features as the claimed procatalyst and its features are described above in connection with the text relating thereto. The cocatalyst is preferably a tri-Cι-C₁₀ alkyl aluminium or a Cι-C₁₀ alkyl aluminium chloride, preferably a tri-Cι-Cιo alkyl aluminium, more preferably a tri-C₂-C alkyl aluminium, most preferably triethyl aluminium. It must be emphasized, that the aluminium compound acting as cocatalyst is separate from the aluminium compound(s) used to prepare the procatalyst. It is used in large amounts in connection to the polymerization and should not be confused with the aluminium compound used to prepare the procatalyst, which is used in small amounts and reacted with the surface of the support. Preferably, the molar ratio between the aluminium of said cocatalyst and the titanium of said procatalyst is 1: 1 - 100: 1, more preferably 2: 1 - 50: 1, most preferably 3: 1 - 20: 1.

As was stated above, the claimed procatalyst has high activity both when preparing high molecular weight and low molecular weight C₂-C₁o olefin polymers. Thus, it is particularly useful in polymerizations, where the molecular weight is regulated e.g. by hydrogen. According to a preferred embodiment, the claimed polymerization is performed in the presence of hydrogen as molecular weight regulating agent.

Most preferably, the claimed polymerization is a multi-step process, in the steps of which different amounts of hydrogen are present as molecular weight regulating agent (so called chain transfer agent). This leads to different molecular weight fractions of the C₂-C*ιo olefin polymer. In the preparation of such tailored polymers, the polymerization rate can with the help of the claimed procatalyst be kept essentially constant and high during the whole process. Further, the obtained polymer is, thanks to the claimed additional chlorination step, clearly more homogenous than before.

A typical multi-step polymerization process is a two-stage process, in which the hydrogen pressures deviate considerably from each other. A broad molecular weight distribution is usually obtained. One such process has been described in EP-B- 517 868.

It should be understood that the multi-step process described above may include additional precontacting or prepolymerization stages, where the catalyst is pretreated or prepolymerized before it is introduced into the first polymerization stage. A process including a prepolymerization stage has been described in WO-A- 96/18662.

In the claimed polymerization process, said C₂-Cι₀ olefin monomer can be any monomer having from two to ten carbon atoms, such as ethylene, propylene, 1- butene, isobutene, 3 -methyl- 1-butene, 1-hexene, 4-methyl-l-pentene, 4,4-dimethyl- 1-pentene, vinylcyclohexane, cyclopentene, cyclobutene and norbornene. It is also suitable e.g. for the copolymerization of ethylene/propylene, ethylene/ 1-butene, ethylene/ 1-hexene, ethylene/l,3-butadiene, ethylene/4-methyl-l-pentene, ethylene/- α-ω-diolefins such as α-ω-octadiene, propylene/cyclopentene, ethylene/norbornene, ethylene/dimethanooctahydronaphthalene and ethylene/propylene/ethylidene norbornene. Most preferably, said C -C₁₀ olefin is ethylene or, optionally, ethylene together with no more than 20 w-% of a C₃-Cιo-α-olefin.

Examples

In the following examples, the claimed procatalyst is prepared, recovered and analyzed. Further, it is tested in the polymerization of ethylene, whereby the obtained ethylene polymer is processed and tested for homogeneity. For comparison, a procatalyst was prepared according to EP 688 794 (lacking the additional chlorination step), recovered, analyzed and tested as polymerization catalyst.

Laboratory:

Catalyst Examples

Preparation of Complex

7.9 g (60.8 mmol) of 2-ethyl-l-hexanol was added slowly to 27.8 g (33.2 mmol) of 19.9% butyl-octyl-magnesium. The reaction temperature was kept under 35 °C. This complex was used in the following catalyst preparations. 2-ethyl-l-hexanol/butyl- octyl-magnesium molar ratio is 1.83 : 1.

Example 1

4.5 g (1.2 mmol/g Si) of 20% EADC was added to 5.9 g of Crosfield ES747JR silica carrier and the mixture was stirred for one hour at 25 °C. 8.9 g (1.4 mmol Mg / g Si) of complex prepared according to complex preparation was added and the mixture was stirred for 4 hours at 35-45 °C. 2.36 ml of 1M solution of BC1₃ (0.4 mmol/g Si) was added and the mixture was stirred for 2 h at 45 °C. Finally 0.8 g (0.7 mmol/g Si) of TiCL; was added and the mixture was stirred for 5 hours at 45 °C. The catalyst was dried at 45-80 °C for 3 hours.

Composition of the catalyst was: Al 2.0 w-%, Mg 2.3 w-%, Ti 2.1 w-%, B 0.2 w-%. Example 2

4.5 g (1.2 mmol/g Si) of 20% EADC was added to 5.9 g of Crosfield ES747JR silica carrier and the mixture was stirred for one hour at 25 °C. 8.9 g (1.4 mmol Mg / g Si) of complex prepared according to complex preparation was added and the mixture was stirred for 4 hours at 35-45 °C. 0.1 g of gaseous HC1 (0.4 mmol/g Si) was added and the mixture was stirred for 2 h at 45 °C. Finally 0.8 g (0.7 mmol/g Si) of TiCL; was added and the mixture was stirred for 5 hours at 45 °C. The catalyst was dried at 45-80 °C for 3 hours.

Composition of the catalyst was: Al 2.0 w-%, Mg 2.1 w-%, Ti 2.1 w-%.

Example 3

4.5 g (1.2 mmol/g Si) of 20% EADC was added to 5.9 g of Crosfield ES747JR silica carrier and the mixture was stirred for one hour at 25 °C. 8.9 g (1.4 mmol Mg / g Si) of complex prepared according to complex preparation was added and the mixture was stirred for 4 hours at 35-45 °C. 1.5 g of 20% solution of ethyl aluminium dichloride (0.4 mmol/g Si) was added and the mixture was stirred for 2 h at 45 °C. Finally 0.8 g (0.7 mmol/g Si) of TiCL; was added and the mixture was stirred for 5 hours at 45 °C. The catalyst was dried at 45-80 °C for 3 hours.

Composition of the catalyst was: Al 2.6 w-%, Mg 2.0 w-%, Ti 2.2 w-%.

Example 4

4.5 g (1.2 mmol/g Si) of 20% EADC was added to 5.9 g of Crosfield ES747JR silica carrier and the mixture was stirred for one hour at 25 °C. 8.9 g (1.4 mmol Mg / g Si) of complex prepared according to complex preparation was added and the mixture was stirred for 4 hours at 35-45 °C. 0.6 g of SnCL, (0.4 mmol/g Si) was added and the mixture was stirred for 2 h at 45 °C. Finally 0.8 g (0.7 mmol/g Si) of TiCL, was added and the mixture was stirred for 5 hours at 45 °C. The catalyst was dried at 45- 80 °C for 3 hours.

Composition of the catalyst was: Al 2.1 w-%, Mg 1.8 W-%, Ti 2.3 w-%.

Comparative Example 5

The catalyst used in this example was one known in the art, prepared according to Patent Application EP-A-688 794 on a 20 μm silica carrier. Comparative Example 6

The catalyst used in this example was one known in the art, prepared according to Patent Application FI 980788.

Polymerization examples

Catalysts were tested in n-pentane slurry homopolymerization in following conditions:

Reactor volume 3 1

Amount of n-pentane 1.8 1

Amount of catalyst 100 mg Al/Ti-ratio 15

Polymerization temperature 90 °C

Amount of hydrogen (in 500 ml bomb 25 °C) 500 kPa Partial pressure of pentane in the polymerization temperature 440 kPa

Total pressure kept with continuous ethylene feed 1440 kPa Polymerization time 1 hour

The measured amount of n-pentane was filled into the reactor and the temperature was increased to 90 °C. Catalyst and cocatalyst were added and ethylene was taken through the hydrogen charging vessel. A total pressure of 14.4 bar was kept with continuous ethylene feed.

Polymerization results

Table 1 Laboratory polymerization results

Pilot:

Polymerization examples

Example 7

Into a 50 dm³ loop reactor were added 7 g/h polymerization catalyst prepared in Example 1, 2 kg/h ethylene, 1,2 g hydrogen and 28 kg/h propane. The temperature was 80 °C and pressure 65 bar. The slurry was continuously removed from the reactor and introduced into a 500 dm³ loop reactor where additional ethylene, hydrogen and propane were added. The polymerization proceeded at 95 °C temperature and 60 bar pressure. The rate of polymerization and the MFR of the polymer are shown in Table 2.

The polymer slurry from the loop reactor was discharged in to a flash tank, where the hydrocarbons were removed and the polymer containing the active catalyst was introduced into a gas phase reactor where the polymerization proceeded. The polymer was then withdrawn from the reactor, mixed with 5.75% carbon black containing masterbatch and compounded in a corotating twin screw extruder.The polymerization rate in the gas phase reactor and the characteristics of the black polymer compound can be seen in Table 2.

Example 8

The polymerization was performed according to Example 7. The data is shown in Table 2.

Example 9

Into a continuously operating stirred tank reactor was introduced hexane diluent, ethylene, hydrogen and a polymerization catalyst prepared according to Example 1 so that MFR₂ of the polymer was 500 g / 10 min and the density 973 kg/m³. The slurry containing the polymer was degassed and introduced into another stirred tank reactor, where additional ethylene, hydrogen and 1-butene comonomer were added, so that a polymer having MFR₅ = 0.43 g / 10 min and content of butene units 1.3% by weight was obtained. The weight ratio of the first stage polymer to the second stage polymer was 48/52. The polymer was dried and compounded with a carbon black containing masterbatch so, that the density of the material was 960 kg/m³ and MFR₅ 0.31 g / 10 min. The ratio MFR₂₁/MFR₅, indicating the broadness of the molecular weight distribution was 28. Comparative Example 10

The polymerization was performed as in Example 7, except that a catalyst prepared according to Example 3 of EP-A-688 794 on a carrier having an average particle size of 20 microns was used. The data is shown in Table 2.

Comparative Example 11

The polymerization was performed as in Example 7, except that a catalyst prepared according to Example 3 of a Finnish Patent Application FI 980788 on a carrier having an average particle size of 20 microns was used. This catalyst is known to produce a homogeneous material.The data is shown in Table 2.

Comparative Example 12

The polymer was produced as in Example 9, but a catalyst was similar to Comparative Example 10. The polymer contained 1.1% by weight butene units and had an MFR₅ = 0.45 g / 10 min. The density of the compound containing carbon black was 961 kg/m³ and MFR₅ 0.38 g / 10 min. The ratio MFR₂₁/MFR₅, indicating the broadness of the molecular weight distribution was 28.

Polymerization results

Table 2 Pilot polymerization data

Example 13

The materials prepared in Examples 7-8 and Comparative Examples 9-11 were evaluated as follows:

The dispersion indicates the homogeneity of the black samples. It is measured from the black pellets according to the ISO/DIS 11420 method as follows: Six pellets are cut using a microtome to 20 μm cuts. Using an optical microscope, the white spots seen in the sample are then measured and classified according to their size. The average number of white spots in each size class is calculated. An ISO value indicating the dispersion is attributed to the material. A high ISO rating denotes a poor homogeneity (large inhomogeneities).

The rheology of polymers has been determined using Rheometrics RDA II Dynamic Rheometer. The measurements have been carried out at 190 °C temperature under nitrogen atmosphere.

The materials from Example 9 and Comparative Example 12 were run into pipes. When the pipes were examined, it was found that the inner surface of the pipe made from the material of Example 9 was smooth but the inner surface of the pipe made from the material of Comparative Example 12 contained gels.

The evaluation results are shown in Table 3. They reveal that the inventive catalyst produces a broad molecular weight distribution (higher SHI and G', compare Examples 7 and 8 with Comparative Examples 9 and 10). Still the homogeneity of the material has not suffered.

When considering the higher molecular weight and broader molecular weight distribution of materials of Examples 7 and 8, the dispersion is comparable to that of Comparative Example 11, where a catalyst producing homogeneous material was used. However, the amount of fines is significantly lower using the inventive catalyst (see Table 2), suggesting a better behaviour of the catalyst in the polymerization process.

Table 3 Evaluation results

Claims

1. A high activity procatalyst for the polymerization of C₂-C₁₀ olefins, which procatalyst has been prepared by contacting:

(a) an inorganic support,

(b) an aluminium compound of the formula (1):

(R_3-n AlCl_n)_m (1)

wherein R is a C₁-C₂0 hydrocarbyl group or a -C₂0 hydrocarbyloxy group, n is 1 or 2, and m is 1 or 2,

(c) a compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, and

(d) a titanium compound having the formula (2)

(OR'V_xTiCL. (2)

wherein R' is a C₂-C o hydrocarbyl group and x is an integer from 0 to 4, characterized by contacting:

(e) a chlorine compound which is either the same or different from said aluminium compound and said titanium compound and is selected from HC1, Cl₂ or a compound having the formula (3)

R'_q-_pMCl_p (3)

wherein each R' is selected from a hydrogen atom, a C₁-C₂₀ hydrocarbyl group and a C₁-C₂₀ hydrocarbyloxy group, or a pair of the R':s may form a double-bonded oxygen, M is a non-titanium element selected from Groups 3-16 of the Periodic Table of the Elements (IUPAC 1990), q is the oxidation state of the element M, and p is a number from 1 to q.

2. A procatalyst according to claim 1, characterized in that said inorganic support is contacted with said aluminium compound to give a first reaction product.

3. A procatalyst according to claim 2, characterized in that said first reaction product is contacted with said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium to give a second reaction product.

4. A procatalyst according to claim 3, characterized in that said second reaction product is contacted with said chlorine compound to give a third reaction product.

5. A procatalyst according to claim 4, characterized in that said third reaction product is reacted with said titanium compound to give a fourth reaction product.

6. A procatalyst according to claim 5, characterized in that said fourth reaction product is recovered as said procatalyst.

7. A procatalyst according to any preceding claim, characterized in that said chlorine compound is a chlorine compound which increases the molar ratios Cl/Al and Cl/Ti of the procatalyst.

8. A procatalyst according to any preceding claim, charaterized in that said chlorine compound is a chlorine compound in gaseous form.

9. A procatalyst according to any preceding claim, characterized in that said chlorine compound is selected from CI₂, HC1 and BC1₃.

10. A procatalyst according to any preceding claim, characterized in that said chlorine compound is BC1₃ or HC1.

11. A procatalyst according to any preceding claim, characterized in that said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is a contact product of a di-CrC₁₀ alkyl magnesium and a -C-₁₂ alcohol.

12. A procatalyst according to claim 11, characterized in that said di-C C₁₀ alkyl magnesium is dibutyl magnesium, butyl ethyl magnesium or butyl octyl magnesium.

13. A procatalyst according to claim 11 or 12, characterized in that said -C₁₂ alcohol is a branched alcohol, preferably a 2-alkyl alkanol, most preferably 2-ethyl- l-hexanol or 2-methyl-l-pentanol.

14. A procatalyst according to claim 11, 12 or 13, characterized in that said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is a contact product of a di- - o alkyl magnesium and a -C₁₂ alcohol in the molar ratio 1:1.3 - 1:2.2, preferably 1: 1.78 - 1: 1.99, most preferably 1:1.80 - 1: 1.98.

15. A procatalyst according to any of claims 3-14, characterized in that said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is contacted with said first reaction product so that the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is in hydrocarbon solution, preferably in a hydrocarbon solution, the viscosity of which is below 10 mPa-s.

16. A procatalyst according to any preceding claim, characterized in that said inorganic support is a mono-oxide or mixed oxide of an element selected from Groups 3-6 and 13-14 of the Periodic Table of the Elements (IUPAC 1990), preferably a mono-oxide or mixed oxide of silicon, aluminium, titanium, chromium and/or zirconium.

17. A procatalyst according to claim 16, characterized in that said inorganic support is a mono-oxide or mixed oxide of silicon and/or aluminium, preferably silica.

18. A procatalyst according to claim 17, characterized in that said inorganic support is a mono-oxide or mixed oxide having surface hydroxyls.

19. A procatalyst according to claim 18, characterized in that said inorganic support is a silica having at the most 2.0 mmol/g of surface hydroxyls.

20. A procatalyst according to any preceding claim, characterized in that said aluminium compound is ethyl aluminium dichloride or ethyl aluminium sesqui- chloride, preferably ethyl aluminium dichloride.

21. A procatalyst according to claims 2-20, characterized in that said aluminium compound is contacted with said inorganic support so that the aluminium compound is in hydrocarbon solution, preferably in a 5-25 w-% hydrocarbon solution, the viscosity of which most preferably is below 10 mPa-s.

22. A procatalyst according to any preceding claim, characterized in that said titanium compound is titanium tetrachloride.

23. A procatalyst according to any preceding claim, characterized in that in the preparation, the molar ratio between said chlorine compound and said aluminum compound is 1:0.5 - 1:50, preferably 1: 1 - 1: 10, most preferably 1:2 - 1:4.

24. A procatalyst according to any preceding claim, characterized in that in the preparation, the molar ratio between said chlorine compound and said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, calculated as magnesium, is 1:0.5 - 1:50, preferably 1: 1 - 1: 10, most preferably 1:2 - 1:5.

25. A procatalyst according to any preceding claim, characterized in that in the preparation, the molar ratio between said titanium compound and said aluminium compound, measured as Ti/Al, is 1: 1 - 1: 10, preferably 1: 1 - 1:5, most preferably 1: 1 - 1:3.

26. A procatalyst according to any preceding claim, characterized in that in the preparation, the amount of said aluminium compound relative to the mass of the inorganic support, measured as mmol Al/g is 0.01 - 100 mmol/g, preferably 0.1 - 10 mmol/g, most preferably 0.5 - 3.0 mmol/g.

27. A catalyst system for the polymerization of C₂-C₁₀ olefins, comprising a procatalyst according to one of claims 1-26, and a separate cocatalyst which is an organometallic compound based on a metal selected from Groups 1 to 3 and 13 of the Periodic Table of the Elements (IUPAC 1990).

28. A catalyst system according to claim 27, characterized in that said cocatalyst is a tri-CrC-io alkyl aluminium or a Cι-C₁₀ alkyl aluminium chloride, preferably a tri-CrCio alkyl aluminium, more preferably a tri-C₂-C₄ alkyl aluminium, most preferably triethyl aluminium.

29. A catalyst system according to claim 27 or 28, characterized in that the molar ratio between the aluminium of said cocatalyst and the titanium of said procatalyst is 1: 1 - 100:1, preferably 2:1 - 50:1, most preferably 3: 1 - 20: 1.

30. Process for the preparation of a high activity procatalyst for the polymerization of C₂-C₁₀ olefins, characterized in that it has been prepared by contacting:

(a) an inorganic support,

(b) an aluminium compound of the formula (1):

(R₃._n AlCl_n)_m (1)

wherein R is a C1-C₂0 hydrocarbyl group or a C₁-C₂₀ hydrocarbyloxy group, n is 1 or 2, and m is 1 or 2, (c) a compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium,

(d) a titanium compound having the formula (2)

(OR')₄-χTiCl_x (2)

wherein R' is a C₂-C ₀ hydrocarbyl group and x is an integer from 0 to 4, characterized by contacting:

(e) a chlorine compound which is either the same or different from said aluminium compound and said titanium compound and is selected from Cl₂ or a compound having the formula (3)

R'_q-_pMCl_p (3)

wherein R' is a C₁-C₂0 hydrocarbyl group or a Cι-C₂o hydrocarbyloxy group, M is an element selected from Groups 3, 4, 13 and 14 of the Periodic Table of the Elements (IUPAC 1990), q is the oxidation state of the element M, and p is a number from 1 to q.

31. A process according to claim 30, characterized in that said inorganic support is contacted with said aluminium compound to give a first reaction product.

32. A process according to claim 31, characterized in that said first reaction product is contacted with said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium to give a second reaction product.

33. A process according to claim 32, characterized in that said second reaction product is contacted with said chlorine compound to give a third reaction product.

34. A process according to claim 33, characterized in that said third reaction product is reacted with said titanium compound to give a fourth reaction product.

35. A process according to claim 34, characterized in that said fourth reaction product is recovered as said procatalyst.

36. A process according to any of claims 30-35, characterized in that said chlorine compound is a chlorine compound which increases the molar ratios Cl/Al and Cl/Ti of the procatalyst.

37. A process according to any of claims 30-36, characterized in that said chlorine compound is a chlorine compound in gaseous form.

38. A process according to any of claims 30-37, characterized in that said chlorine compound is selected from CI₂, HC1 and BC1₃.

39. A process according to any of claims 30-38, characterized in that said chlorine compound is BC1₃ or HC1.

40. A process according to any of claims 30-39, characterized in that said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is a contact product of a di-Cι-Cιo alkyl magnesium and a C^*t-C₁₂ alcohol.

41. A process according to claim 40, characterized in that said di-Cr o alkyl magnesium is dibutyl magnesium, butyl ethyl magnesium or butyl octyl magnesium.

42. A process according to claim 40 or 41, characterized in that said CrC₁₂ alcohol is a branched alcohol, preferably a 2-alkyl alkanol, most preferably 2-ethyl hexanol or 2-propyl pentanol.

43. A process according to claim 40, 41 or 42, characterized in that said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is a contact product of a di-CrC₁₀ alkyl magnesium and a CrC₁₂ alcohol in the molar ratio 1: 1.3 - 1:2.2, preferably 1:1.78 - 1: 1.99, most preferably 1: 1.80 - 1:1.98.

44. A process according to any of claims 32-43, characterized in that said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is contacted with said first reaction product so that the compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium is in hydrocarbon solution, preferably in a hydrocarbon solution, the viscosity of which is below 10 mPa-s.

45. A process according to any of claims 30-44, characterized in that said inorganic support is a mono-oxide or mixed oxide of an element selected from Groups 3-6 and 13-14 of the Periodic Table of the Elements (IUPAC 1990), preferably a mono-oxide or mixed oxide of silicon, aluminium, titanium, chromium and/or zirconium.

46. A process according to claim 45, characterized in that said inorganic support is a mono-oxide or mixed oxide of silicon and/or alumimum, preferably silica.

47. A process according to claim 46, characterized in that said inorganic support is a mono-oxide or mixed oxide having surface hydroxyls.

48. A process according to claim 47, characterized in that said inorganic support is a silica having at the most 2.0 mmol/g of surface hydroxyls.

49. A process according to any of claims 30-48, characterized in that said aluminium compound is ethyl aluminium dichloride or ethyl aluminium sesqui- chloride, preferably ethyl aluminium dichloride.

50. A process according to claims 31-49, characterized in that said aluminium compound is contacted with said inorganic support so that the aluminium compound is in hydrocarbon solution, preferably in a 5-25 w-% hydrocarbon solution, the viscosity of which most preferably is below 10 mPa-s.

51. A process according to any of claims 30-50, characterized in that said titanium compound is titanium tetrachloride.

52. A process according to any of claims 30-51, characterized in that in the preparation, the molar ratio between said chlorine compound and said aluminum compound is 1:0.5 - 1:50, preferably 1: 1 - 1:10, most preferably 1:2 - 1:4.

53. A process according to any of claims 30-52, characterized in that in the preparation, the molar ratio between said chlorine compound and said compound or mixture containing hydrocarbyl and hydrocarbyl oxide linked to magnesium, calculated as magnesium, is 1:0.5 - 1:50, preferably 1: 1 - 1:10, most preferably 1:2 - 1:5.

54. A process according to any of claims 30-53, characterized in that in the preparation, the molar ratio between said titanium compound and said aluminium compound, measured as Ti/Al, is 1:1 - 1: 10, preferably 1: 1 - 1:5, most preferably 1: 1 - 1:3.

55. A process according to any of claims 30-54, characterized in that in the preparation, the amount of said aluminium compound relative to the mass of the inorganic support, measured as mmol Al/g is 0.01 - 100 mmol/g, preferably 0.1 - 10 mmol/g, most preferably 0.5 - 3.0 mmol/g.

56. Process for the polymerization of C -C₁₀ olefins, characterized in that at least one C₂-C₁₀ olefin is under polymerization conditions contacted with a procatalyst according to one of claims 1-26, and a separate cocatalyst which is an organometallic compound based on a metal selected from Groups 1 to 3 and 13 of the Periodic Table of the Elements (IUPAC 1990).

57. A process according to claim 56, characterized in that said procatalyst is a tri- Ci-Cio alkyl aluminium or a CrC₁₀ alkyl aluminium chloride, preferably a tri-Cr Cio alkyl aluminium, more preferably a tri-C₂-C alkyl aluminium, most preferably triethyl aluminium.

58. A process according to claim 56 or 57, characterized in that the molar ratio between the aluminium of said cocatalyst and the titanium of said procatalyst is 1 : 1 - 100: 1, preferably 2: 1 - 50: 1, most preferably 3 : 1 - 20: 1.

59. A process according to claim 56, 57 or 58, characterized in that said polymerization is performed in the presence of hydrogen as molecular weight regulating agent.

60. A process according to any of claims 56-59, characterized in that said C₂-C₁₀ olefin is ethylene or, optionally, ethylene and no more than 20 w-% of a C₃- ₀ olefin.

61. A process according to any of claims 56-60, characterized in that said polymerization is performed in at least two stages, where at least one stage is performed at a relatively low hydrogen concentration and at least one stage is performed at a relatively high hydrogen concentration.