FI85710C - Process for Preparing an Olefin Polymerization Dedicated Catalyst Drying Component and Its Use - Google Patents

Description

8571 0

The invention relates to a solid procatalyst composition of an alpha-olefin polymerization catalyst system consisting essentially of a magnesium and chlorine-containing support component, a transition metal compound and optionally an electron donor. The invention relates to a process for the preparation of such a procatalyst composition, which a) contacting magnesium sulphate in the form of an aqueous solution or alcoholic suspension with an aqueous solution of calcium chloride, b) treating the thus obtained solution or suspension with a solid support component and c) to form a solid procatalyst composition.

The invention further relates to the use of a procatalyst composition of this type together with an aluminum organococatalyst compound and optionally an external donor for the polymerization or copolymerization of alpha-olefins, in particular ethylene.

For the polymerization of olefins, the so-called Ziegler-Natta-kata-30 lytic system consisting of the so-called procatalytic and cook-lytic. The procatalyst is based on a transition metal compound of Groups IVB-VIII of the Periodic Table of the Elements and the cocatalyst is based on an organometallic compound of a metal of Groups IA-IIIA of the Periodic Table of the Elements. Catalyst systems generally also include electron donors and possibly other compounds that enhance and modify catalytic properties.

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In the preparation of heterogeneous polymerization catalysts, it is customary to use a support compound on which the transition metal compound is deposited as a component for improving the polymerization activity of the procatalysts. Magnesium compounds, such as alkoxides, hydroxides, hydroxy halides and halides, which have proven to be the most important carrier components of procata-lytic compositions, have recently proved to be important carrier compounds.

Since magnesium halides in their basic crystal form are not very efficiently activated by the transition metal compound, the crystal structure must be deformed. Traditionally, this is done by grinding, e.g. in a ball mill, which results in a fine powder with a typically high specific surface area, the crystal lattices of the particles of which are strongly deformed. When such a powder is activated to a procatalyst composition by a transition metal compound, and then reduced with an organometallic compound acting as a cocatalyst, a very active polymerization catalyst is obtained.

However, the conventional method of grinding magnesium halides has the disadvantage that it consumes a very large amount of Energi-25, causes wear and corrosion of the equipment, and is only suitable for the preparation of a catalyst by a high-capacity batch process. A newer and more effective way to reduce the crystallinity of magnesium halides and thus increase their ability to be activated by transition metal compounds is to chemically modify them during or after manufacture. Such modified magnesium halides include e.g. magnesium halides modified in the crystallization step with various excipients and compounds obtained by halogenation from organomagnesium compounds.

Methods for preparing a carrier component based on the interaction of magnesium salts and other inorganic salts in solution are also known. An example of such a process for the preparation of magnesium halide is FI patent publication 75843, in which the carrier component is made of magnesium sulphate and barium or calcium chloride. First, the magnesium sulfate in the form of an aqueous solution or an alcoholic suspension is contacted with an aqueous or alcoholic solution of barium or calcium chloride. The insoluble portion is then separated from the solution or suspension. If water has been used as the solvent, the solution is then evaporated to dryness and the solid residue obtained is heated above the boiling point of water, after which the solid residue is dissolved in alcohol. Finally, the alcoholic solution of the magnesium and sulfate substantially free magnesium component is dried by periodic azeotropic distillation. The solid carrier component is recovered by reprecipitation from an alcoholic solution. Activation of the carrier component was performed by contacting it with a titanium halide compound and possibly an electron donor.

Such a method gives an active procatalyst composition, but only with an extremely multi-step, laborious and interfering method.

It is an object of the present invention to improve such a process in which the starting material is very cheap inorganic salts. The invention also seeks to provide a solid procatalyst composition having a suitable particle size distribution, shape and morphology and is easily adjustable.

It is also an object to find and use the most efficient drying method in a process in which a procatalyst composition is prepared from inorganic starting materials.

The invention relates to a process for preparing a procatalyst composition 35 having the above-mentioned steps, i.e. 4 65710 a) contacting magnesium sulphate in the form of an aqueous solution or alcoholic suspension with an aqueous solution of calcium chloride, 5 b) treating the resulting solution or suspension to form a solid support component and contacting the transition metal compound and optionally an internal electron donor to form a solid procatalyst composition. The method is characterized by what is said in the characterizing part of claim 1. The realization of the process is thus based on the fact that the solution or suspension obtained from step a) can be spray-dried into a solid carrier component which is substantially as active as the previous carrier components, although calcium and sulphate ions have not been removed.

The invention also relates to the use of a procatalyst composition prepared by said process together with aluminum or a corresponding organometallic cocatalyst compound and optionally an external electron donor for the polymerization and copolymerization of alpha-olefins.

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The process according to the invention thus begins by contacting magnesium sulphate in the form of an aqueous solution or an alcoholic suspension with an aqueous or alcoholic solution of calcium chloride. As the solvent, water or alcohols such as ethanol, methanol or a mixture thereof can be used. The use of water gives a solution of magnesium sulphate, while the use of alcohol gives a suspension. The most preferred 5,85710 alcohol is ethanol. The amount of magnesium sulfate in solution or suspension can vary within wide limits. The useful range is about 1-50% by weight of magnesium sulfate.

According to the invention, the contacting of the magnesium sulphate solution or suspension with the calcium chloride is preferably carried out by preparing an aqueous or alcoholic solution of the calcium chloride, the concentration of which can vary from 1% to a saturated solution. The magnesium-10 sulfate solution or suspension is then mixed with the calcium chloride solution to precipitate calcium sulfate. The calcium chloride solution is preferably used in a stoichiometric ratio to magnesium, although this is not necessary. The solid magnesium compound used in the process is of the form MgSO 4 .xHaO.yROH, where x, y = 0-7; x + y = 0-7 and a solid calcium compound of the form CaCla.xHaO.yROH, where x, y = 0-7; x + y = 0-7.

The reaction product obtained from the first step is in the form of a suspension 20 in which the magnesium and chloride ions are dissociated and the calcium and sulphate ions associated with the calcium sulphate precipitate. This suspension is then treated to form a solid carrier component. This is done by spray drying, in which the suspension is introduced in spray form into a hot gas stream to evaporate the solvent and form a solid, dry carrier component.

Spray drying can be performed in a large chamber through which hot gas, such as nitrogen, is blown and into which the suspension is sprayed by means of a suitable atomizer. The nebulizer may be any suitable nebulizer, such as a two-liquid pneumatic nozzle for forming small droplets, a single-liquid pressure nozzle for producing larger droplets and dust-free products, or a high-speed rotary plate sprayer for producing droplets of different sizes.

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The shape and volume of the chamber, as well as the drying and spray gas velocities and temperatures, can be freely changed to provide dry and properly sized carrier particles.

In the method according to the invention, the spray-drying is preferably carried out by means of a single liquid pressure nozzle, the diameter of the opening of which is preferably of the order of about 0.5 mm. The drying is preferably performed at a temperature of about 80-300 ° C. The outlet temperature of the drying gas is between about 100-130 ° C 10 and the inlet temperature depends on the ratio of the mass flows of the drying gas and the liquid to be dried. As the spray and drying gas, any gas which is stable and inert under the drying conditions can be used, such as air or, preferably, nitrogen gas.

Spray drying results in a carrier component based on magnesium chloride and calcium sulfate. A typical carrier component of the invention contains about 2-15% by weight of magnesium, about 5-35% by weight of calcium, about 5-30% by weight of chloride ion and about 10-40% by weight of sulfate ion prior to activation with the transition metal compound. If the solvent has been ethanol, small amounts may have remained in the carrier component. The spray-dried carrier component is in the form of a powder, preferably having a particle size of between about 1 and 100 micrometers.

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Finally, the solid support component is contacted with the transition metal compound and optionally an internal electron donor to form a solid procatalyst composition. This is done, for example, by mixing said component with a transition metal compound, preferably a titanium halide compound and most preferably titanium tetrachloride, one or more times. Prior to, during or after activation, the procatalyst mixture may further be treated with an internal electron donor compound. The activation with the transition metal compound is preferably carried out in two steps, between which an internal electron donor, usually of the amine, ether or ester type, can be added. A suitable donor is e.g.

7,85710 diisobutyl phthalate in an amount of about 0.05 to 0.3 mol / mol Mg.

In the first activation step, it is recommended to use 5 low temperatures, e.g. below 0 ° C, preferably below -20 ° C. The second activation step can be performed at a higher temperature, e.g. 85-120 ° C, where a reaction time of about 1-1.5 hours is sufficient. The solid reaction product is then separated from the liquid phase and washed, e.g. with a hydrocarbon solvent, to remove impurities and derivatives. The solid procatalyst composition thus obtained can be dried under a light vacuum or nitrogen gas at room temperature or at a slightly higher temperature.

The solid procatalyst composition according to the invention is characterized in that its carrier component essentially also contains calcium and sulphate. The amount of calcium is preferably about 1 to 30% by weight, more preferably about 10 to 25% by weight. A typical procatalyst composition includes e.g.

About 2-3% by weight of titanium, about 5-10% by weight of magnesium, about 10-25% by weight of calcium, about 20-40% by weight of chlorine ion and about 20-50% by weight of sulfate ion. If an alcohol such as ethanol is used as the solvent, it may also contain small amounts of this alcohol, e.g. 0.05-0.5% by weight. The product is also characterized by a powder diffraction spectrum from which only calcium sulphate can be identified using dry starting materials and calcium sulphate hemihydrate, CaSCU.0.5 HaO, using water-rich starting materials.

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The procatalyst composition of the invention can be advantageously used in conjunction with a metal of Groups IA-IIIA of the Periodic Table of the Elements, such as aluminum, an organometallic cocatalyst compound, and optionally an external electron donor, for the polymerization and copolymerization of alpha-olefins.

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Preferred cocatalysts are organometallic and organohalogenometallic compounds of aluminum, preferably trialkylaluminum such as triethylaluminum.

As an external electron donor, e.g. amines, ethers, esters (preferably alkyl and aryl esters of aromatic carboxylic acids) or silane compounds (alkyl / arylsilanes), examples of which include e.g.

Methyl and ethyl esters of benzoic, toluic and phthalic acids, isobutyl esters of phthalic acid, triethoxysilane, etc. These electron donors are compounds capable of forming complexes with aluminum alkyls.

The procatalyst composition of the invention, the organometallic cocatalyst compound and the optional external electron donor are mixed together at an Al / Ti molar ratio of between about 10-300 and the optional external electron donor and Al compound at a molar ratio of about 20, depending on the polymerization system. The polymerization can be carried out either as a suspension or bulk polymerization or in the gas phase. The procatalyst compositions of the invention and their various combinations can be used to polymerize and copolymerize alpha-olefins such as ethylene, propylene, 1-butene and 1-methyl-1-pentene, especially ethylene.

The following are a few embodiments to illustrate the invention.

30 Example 1

The starting materials for the support were 40.0 g MgSO 4 .H 2 O and 18.0 g CaCl 2. The starting materials were dispersed before spraying in dry alcohol (800 g) in an Erlenmeyer vessel under a nitrogen atmosphere. Dispersion was done with a magnetic stirrer and the dispersion time was 35 days.

The spray drying of the support was carried out with a nozzle having a diameter of 0.5 mm, nitrogen was used as the spraying gas and 85710 9 drying gas was used. The inlet temperature of the drying gas was 195-210 ° C, the outlet temperature 100-105 ° C-The carrier contained Mg 8.7 wt%, Ca 23.2 wt%, Cl-12.5 wt%, SO-.2- , 34.0 wt% and ethanol 6.8 wt%.

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Activation was performed in a 500 dm3 glass reactor equipped with temperature measurement, efficient mixing and a reflux condenser. The carrier was weighed into a reactor of about 10 g in a nitrogen cabinet, which was cooled with a dry ice-heptane-10 bath. At the same time, 100 ml of heptane was added to the reactor via addition funnel as a medium. After the temperature dropped to -20 ° C, 200 ml of TiCl 4 was added so that the temperature of the mixture remained at -20 ° C at all times.

The temperature was raised to 0 ° C within one hour, from which it was further raised to 110 ° C evenly over two hours. At this temperature, the solution refluxed, which was allowed to proceed for one hour. Stirring was stopped, the heating bath was removed and the solid was allowed to settle. The solution was siphoned and 200 mL of TiCl 4 was added. The mixture was stirred for 1 hour at 120 ° C. The mixture was allowed to sediment and the TiCl 3 solution was siphoned off the support. To the reactor was added 200 ml of heptane, which was washed from the catalyst with harmful Ti compounds for 15 minutes at 80 ° C. The washing solution was siphoned and the washing was performed in the same manner four more times.

The catalyst was dried over a stream of pure nitrogen from heptane. The yield was about 7 g. The procatalyst contained Ti 2.5 wt%, Mg 6.4%, Ca 20.2%, Cl 22.4%, SO · .2-46.3% and ethanol 0.1%. The X-ray diffraction spectrum of the procatalyst on the support is shown in Figure 1.

The procatalyst was tested in the polymerization of ethylene as follows. 1.8 dm3 of pentane was used as the medium in the 3 dm3 reactor. A 300 ml cocatalyst tank was also filled with pentane so that the TEA used as cocatalyst could be flushed into the reactor.

β c 71 n 10 öo,, υ

The procatalyst, used at about 30 mg, was weighed in a nitrogen cabinet into a catalyst bomb. The weighing vessel and bomb walls were flushed with pentane to obtain the procatalyst 5 more accurately from the bomb to the reactor. The catalyst bomb was pressurized with nitrogen having an overpressure of three bar to transfer the procatalyst to the reactor.

The cocatalyst, AlEt3 10 (TEA) in all polymerizations, was injected into the reactor as a 10 wt% pentane solution.

TEA was added so that the titanium / TEA molar ratio in the catalyst was 100. After the addition of TEA and catalyst, stirring and heating of the reactor was started.

A tank with a volume of 500 ml was filled with hydrogen to a pressure of 5 bar. When the temperature rose to 70 ° C, the valves of the ethylene line were opened up to the reactor, whereby first hydrogen, then ethylene entered the reactor space. The temperature was allowed to rise to 90 ° C, which took 4-7 min. The temperature was maintained at 90 ° C until the end of the polymerization. Using ethylene pressure, the total pressure was adjusted to 15 bar at 90 ° C. The partial pressure of ethylene was about 9 bar and that of hydrogen 0.8 bar.

The activity of the procatalyst in the polymerization was 13.1 kg of poly-25 ethylene / (g cat. H). The polymer had a bulk density of 0.947 kg / dm 3, a bulk density of 0.18 kg / dm 3 and a weight average molecular weight of 286,500 g / mol.

Example 2 The starting materials for the carrier were 19.5 g of dry MgSO 4 and 18.0 g of CaCl 2. Prior to spraying, the starting materials were dispersed in dry alcohol (800 g) in an Erlenmeyer flask under a nitrogen atmosphere. Dispersion was done with a magnetic stirrer and the dispersion time was one day.

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The support was spray dried in the same manner as in Example 1. The support contained Mg 4.7 wt%, Ca 18.0 wt%, Cl- 18.5 wt%, SO * 2-19.5 wt% and ethanol 8.9 wt%.

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Activation was performed in the same manner as in Example 1. The procatalyst contained Ti 2.5 wt%, Mg 5.2 wt%, Ca 19.3 wt%,

Cl- 22.8 wt%, SO 2 * -34.4 wt% and ethanol 0.1 wt%. The X-ray diffraction spectrum of the Prokata-5 lyt is shown in Figure 2.

The polymerization was carried out as in Example 1. The activity of the procatalyst was 13.7 kg / (g cat. H). The polymer had a bulk density of 0.956 kg / dm 3 and a bulk density of 0.18 kg / dm 3.

The weight average molecular weight was 290,000 g / mol.

Example 3

The starting materials for the support were 40.0 g MgSO 4 .7H 2 O and 14.0 g CaCl 2. The molar ratio of carriers was 1.3. The starting materials were dispersed before spraying in dry alcohol (800 g) in an Erlen-Meyer vessel under a nitrogen atmosphere. Dispersion was done with a magnetic stirrer and the dispersion time was one day.

The carrier was spray dried as in Example 1. Carrier 20 contained Mg 8.1 wt%, Ca 12.6 wt%, Cl- 13.5 wt%, SO * 2-40.4 wt% and ethanol 5.8 wt%.

Activation was performed in the same manner as in Example 1. The procatalyst contained Ti 2.7 wt.%, Mg 7.0 wt.%, Ca 11.9 wt.%, Cl Cl - 21.4 wt.%, SO42 - 40.4 p. -% and ethanol 0.2% by weight.

The polymerization was carried out as in Example 1. The activity of the procatalyst was 10.3 kg / (g cat. H). The polymer had a bulk density of 0.955 kg / dm 3 and a bulk density of 0.18 kg / dm 3.

The weight average molecular weight was 325,000 g / mol.

Example 4

The starting materials for the support were 60.1 g MgSO 4 .7HaO and 27.1 g CaCl 2. The starting materials were dispersed in water (35 g) in an Erlenmeyer flask under a nitrogen atmosphere before spraying. Dispersion was performed with a magnetic stirrer and the dispersion time was one day.

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In spray drying, the inlet temperature of the drying gas was 180-200 ° C and the outlet temperature 114-125 ° C. Air was used as the drying gas. Otherwise, the carrier was spray dried as in Example 1. The carrier contained Mg 7.6 wt%, Ca 11.7 wt% 5%, Cl-18.3 wt%, SO * 2-15.4 wt%.

Activation was performed as in Example 1. The procatalyst contained Ti 2.9 wt%, Mg 9.0 wt%, Ca 15.4 wt%, Cl- 34.2 wt%, SO * 2-26.5 wt%.

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The polymerization was carried out as in Example 1. The activity of the procatalyst was 5.2 kg / (g cat. H). The bulk density of the polymer was 0.955 kg / dm 3 and the bulk density was 0.12 kg / dm 3. The mass average molecular weight was 282,000 g / mol.

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Figures 1 and 2 show the analysis results of Examples 1 and 2.

Figure 1 shows the X-ray diffraction spectrum of the proca-20 talc of Example 1. The starting materials for the support were 40.0 g MgSO 4 .7H 2 O and 18.0 g CaCl 2.

Figure 2 shows the X-ray diffraction spectrum of the procatalyst of Example 2. The starting materials for the support were 9.5 g of dry 25 MgSO 4 .7H 2 O and 18.0 g of CaCl 2.

The spectra show that the procatalyst composition according to the invention is also characterized by a powder diffraction spectrum from which only 30 CaSO 4 can be identified when using dry starting materials or CaSO 3 .0.5H 2 O when using water-rich starting materials.

The method and product according to the invention have e.g. the following advantages over the prior art: 35 - The CaSO * formed in the preparation of the carrier does not have to be separated from the solution.

8571 0 13 - Spray-drying makes it possible to easily adjust the particle size distribution of the support and, through it, the catalyst and the polymer powder, and also to make it narrower than other manufacturing methods.

5 - Preparation is simple, reagents are cheap and preparation is easily automated. For these reasons, the preparation of the catalyst is cheaper than known methods.

10 - Particle shape can be adjusted.

- The activity of the catalyst can be changed by using different ratios of starting materials.

15 - It is also possible to prepare the carrier by dispersing the starting materials in aqueous solution. In this case, there is no need to pay attention to the anhydrous nature of the starting materials.

Claims (10)

14 85 710 A process for preparing a solid procatalyst composition for an α-olefin polymerization catalyst system, comprising a) contacting magnesium sulfate in the form of an aqueous solution or an alcoholic suspension with an aqueous solution of calcium chloride, b) treating the resulting suspension with a solid support and forming a solid support component. optionally with an internal electron donor to form a solid procatalyst composition, characterized in that step b) comprises spray-drying the suspension obtained from step a), i.e. in spray form, into a hot gas stream to form a solid support component. 20 A method according to claim 1, characterized in that the spray drying is performed by means of a single liquid pressure nozzle, the diameter of the opening of which is preferably of the order of about 0.5 mm. 25 Process according to Claim 1 or 2, characterized in that the spray drying is carried out at a temperature of about 80 to 300 ° C. Process according to one of Claims 1 to 3, characterized in that the alcohol ROH is ethanol, methanol or a mixture thereof, preferably ethanol. Process according to one of Claims 1 to 4, characterized in that the magnesium compound used is, before spray-drying, in the form MgSO4.xH 2 O.yROH, in which x, y * 0-7 and x + y * 0-7, preferably x - 0, 5 or 0 and y * 0, and is 8571 0 the calcium compound is, before spray-drying, in the form CaCl2 * mH2O.nROH, where m, n = 0-7 and m + n = 0-7. Process according to one of the preceding claims, characterized in that so much calcium chloride is added that the procatalyst composition contains about 1 to 30% by weight, preferably about 10 to 25% by weight, of calcium, a support component and a transition metal compound. of the total weight. Process according to one of the preceding claims, characterized in that the transition metal compound is a titanium compound, preferably titanium tetrachloride. Process according to Claim 7, characterized in that magnesium sulphate, calcium chloride and titanium tetrachloride are added so that the composition of the procatalyst composition, based on the total weight of the support component and titanium tetrachloride, is: about 2 to 4% by weight of titanium, about 5 to 10% by weight of magnesium, about 10 to 25% by weight of calcium-20% calcium, about 20 to 40% by weight of chlorine ion and about 20 to 50% by weight of sulfate ion. Process according to one of the preceding claims, characterized in that the procatalyst composition is prepared in the form of particles with a size of about 1 to 100 μm. Use of a solid procatalyst composition prepared by a process according to any one of claims 1 to 9 in combination with an aluminum organometallic cocatalyst compound 30 and optionally an external electron donor for the polymerization of an α-olefin such as ethylene, propylene, 1-butene or 4-methyl-1-pentene, especially ethylene or copolymerized. 16 8571 0