Catalyst components and catalyst for polymerization of olefines as well as methods of obtaining them

The present invention relates to a catalyst component for olefin polymerization and a method for producing a catalyst component.

Olefin polymerization catalysts containing tobacco halide supported on anhydrous magnesium halides in active form are widely described in the patent literature.

Since the U.S. Patent Nos. No. 4,298,718 and No. 4,495,338, for the first time, the use of magnesium halides in active form as carriers for Ziegler-Natta catalysts has been described, and the patent literature in this area is becoming more and more extensive.

The most active forms of magnesium halides are characterized by an X-ray spectrum in which the reflex of maximum intensity occurring in inactive halides no longer occurs, but is replaced by a halo with the maximum intensity shifted towards smaller angles relative to the reflex angles of maximum intensity in the inactive halide.

In the less active forms of magnesium chloride, the reflex with maximum intensity that occurs at 2.56 A (20 0 = 35 °) is not present, but is replaced by a halo with a maximum intensity between the angles of 2 33 33 ° and 35 °, where reflex at 2 0 14.95 ° is always present.

The introduction of magnesium chloride based catalysts in industrial practice has enabled significant simplification of polyolefin production processes. In particular, the possibility of obtaining catalysts in the form of spherical particles has allowed the production of polymers that copy the catalyst form, have satisfactory morphological characteristics (flowability and bulk density) and do not require granulation, which is known to be expensive in terms of energy consumption.

Examples of controlled particle size catalysts are described in U.S. Patent No. 3,954,114.

r The polymer (polyethylene) which can be obtained using these catalysts has very good morphological characteristics, however the yield of these catalysts is not high (usually from 2000 to 15000 g / g catalyst). When the polymer yield increases to values ​​higher than 20,000 g / g of catalyst, the polymer particles formed are brittle and the apparent density is very low.

The catalyst components described in the above-mentioned US patent are made from the MgCU * 6H2O adduct, which was transformed into spheres in a dry-cooling apparatus, and then reacted with TiCU.

U.S. Patent No. 4,399,054 describes catalyst components for olefin polymerization, which are further suitable for producing a polymer (polypropylene) with good flowability and bulk density. The polymer yield when using such a catalyst is not very high (from 3000 to 9000 g / g catalyst, when polymerized in heptane at 70 ° C for 4 hours at a partial pressure of propylene of 0.68 MPa).

The catalyst components are made from MgCk adducts with alcohols, in the form of spherical particles usually containing 3 moles of alcohol.

Before the reaction with TiCU, the alcohol content is reduced to 2.5-2 moles, resulting in non-brittle spherical polymer forms using such catalysts. The alcohol content never drops below 2 moles, as it drastically reduces the catalyst activity.

In the case of magnesium chloride, at least in less active forms (those in the spectrum of which there are two halo with intensity peaks between 20 angles from 30.45 ° to

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31 ° and 33.5 ° to 35 °), the reflex that in the spectrum of inactive magnesium chloride occurs at 14.95 ° is still present.

The invention relates to a catalyst component for olefin polymerization of the formula CH2 = CHR, in which R is a hydrogen atom, an alkyl or aryl group with 1-8 carbon atoms, suitable for the preparation of catalysts with which polymers are obtained in the form of spherical particles with optimal morphological characteristics (flowability and bulk density). In addition, the catalysts have significant catalytic activity and stereospecificity.

The catalyst component of the invention contains titanium halide alcohol or titanium halide supported on anhydrous magnesium chloride.

The catalyst component of the invention is in the form of spherical particles with an average diameter of 10 to 350 μιη, having a specific surface area of ​​20 to 250 m²/ g, greater than 0.2 cm porosity³, X-ray spectrum (CuK a), in which (a) reflections occur at 2 0 35 ° and 14.95 ° (characteristic for magenzene chloride) or (b) reflections at 2 0 35 ° is replaced by a halo with maximum intensity between angles 2 0 33.5 ° and 35 °, and reflexes at 2 0 14.95 °.

The catalyst component may additionally contain an electron-donor compound (internal donor) in a molar ratio to magnesium chloride in the range of 1: 4 to 1:20.

Electron donor compounds can be selected from ethers, esters, amines, ketones. Preferred compounds are the alkyl, cycloalkyl and aryl esters of polycarboxylic acids such as phthalic and maleic acid and the ethers of the formula represented in the drawing wherein R¹ and R¹¹are the same or different and are alkyl, cycloalkyl or aryl radicals with 1-18 carbon atoms, R¹¹¹ and R^IV are the same or different and are alkyl radicals with 1-4 carbon atoms. Ethers of this type are described in US Patent Application No. 3,592234, filed May 31, 1989.

Examples representing these compounds are n-butyl phthalate, diisobutyl phthalate, di-n-octyl phthalate, 2-methyl-2-isopypyyl-1,3-dimethoxypropane, 2-methyl-2 ^ and ^ utyl <^^ 1 , 3-dimethoxypropane, 2,2-diisobutyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane.

ASTM D-3854 standard is cited for the definition of magnesium chloride X-ray spectrum. Spectra are obtained using copper anti-cathode and K a radiation.

The spectrum with the characteristic (a) is appropriate for catalytic components with a specific surface area less than 70-80 m²/ g and porosity greater than 0.4 cm³/ G. The spectrum with the characteristic (b) is appropriate for components with a specific surface area greater than 60 m2 / g and a porosity of 0.25 to 0.4 cm³/ G.

The pore volume distribution is such that more than 50% of the pores have a radius greater than 100 A. In components with an area less than 100 m2 / g, more than 70% of the pores have a radius greater than 100 A.

As already indicated, the catalyst components of the invention can be used to produce catalysts suitable for the production of olefin (co) polymers in the form of spherical particles with valuable morphological characteristics (high bulk density), flowability and mechanical resistance). The average diameter of polymer particles is from 50 to 5000 gm.

In particular, catalysts obtained from components with a specific surface area less than 100m2 / g and a porosity greater than 0.4cm³/ g are suitable for the production of high and low density ethylene polymers (HDPE and LLDPE). Catalysts have very high activity, and the resulting spherical polymer has attractive morphological features (very high bulk density, flowability and mechanical strength).

Catalysts obtained from components with a specific surface area greater than 60-70 m2 / g and a porosity less than 0.4 cm³/ g are preferred for use in the preparation of crystalline propylene polymers and copolymers, so-called impact copolymers obtained from subsequent polymerizations of (1) propylene and (2) mixtures of ethylene and propylene. They are also conveniently used for the production of ethylene propylene rubbers (EP rubbers) or ethylene propylene diene rubbers (EPDM rubbers) and propylene polymer compositions that contain such rubbers.

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Using the catalyst made using the component of the invention, the above types of rubbers with spherical particles, good flowability and bulk density can unexpectedly be obtained, whereas up to now it has not been possible to obtain elastomeric polymers of the types mentioned above, with granular liquid particles due to insurmountable problems of contamination reactors and / or particle agglomeration.

Especially in the case of polypropylene, using stereospecific catalysts obtained from components of the invention with a specific surface area of ​​about 60-70 m²/ g, porosity less than 0.4 cm³/ g and X-ray spectrum (b), it is possible to obtain crystalline polypropylene and copolymers of propylene and ethylene, containing less ethylene, characterized by significantly increased porosity, which makes them very attractive for the production of masterbatches with pigments and / or additives.

It is also amazing that very active catalysts are obtained from the component of the invention although the magnesium chloride contained therein has x-ray characteristics specific to low-magnesium magnesium chloride. Finally, it is surprising and completely unexpected that magnesium chloride is present in the crystalline form, with the X-ray spectrum indicated in (b).

The method for producing the olefin polymerization catalyst component of the invention consists in partially dealcoholizing the magnesium chloride / alcohol adduct to an alcohol content in the adduct from 0.15 to 2 moles per mole of MgCL and reacting such partially dealcoholized adduct with the halalkoxide or titanium halide.

A preferred embodiment of the invention consists of starting from magnesium chloride / alcohol adducts containing so many moles of alcohol that the adduct is solid at room temperature, but melts at temperatures between 100 and 130 ° C.

The number of moles of alcohol varies depending on the type of alcohol.

Adducts with alcohols of the formula ROH in which R is an alkyl, cycloalkyl or aryl group with 1-12 carbon atoms are suitable. Adducts with mixtures of these alcohols can also be used. Examples of alcohols are methanol, ethanol, propanol, butanol, 2-ethylhexanol and mixtures thereof.

For alcohols such as ethanol, propanol, butanol, the number of moles in the adduct is about three per mole of MgCL. The alcohol and magnesium chloride are mixed in the inert liquid hydrocarbon immiscible with the adduct, bringing the adduct to its melting point. The mixture is stirred vigorously (using, for example, an Ultra Turrax T-45N apparatus rotating at 2000-5000 rpm (Jonke and Kunkel (KG IKG. Werkel)). The resulting emulsion is cooled in a very short time. This solidifies the adduct in the form of spherical particles of the desired dimensions. The particles are dried and then subjected to partial de-alcoholization by heating to temperatures ranging from 50 ° C to 130 ° C.

The partially de-alcoholised adduct is in the form of spherical particles with an average diameter of 50 to 350pm, specific surface area of ​​10 to 50 m²/ g and a porosity of 0.6 to 2 cm²/ g (measured with a mercury porosity meter).

The higher the degree of alcohol removal, the higher the porosity. The pore volume distribution is such that more than 50% of the pores have a radius greater than 10000A. De-alcoholization is carried out up to an alcohol content of not more than 2 moles per mole of MgCfe, preferably from 0.15 to 1.5 moles, particularly preferably from 0.3 to 1.5 moles. When de-alcoholization is carried out to values ​​lower than 0.2 mole of alcohol per mole of MgCL, the catalytic activity is significantly reduced.

The partially dealcoholized adduct is then suspended in cold TiCL in concentration

40-50 g / 1 and brought to a temperature of 80-135 ° C and kept at this temperature for 0.5 to 2 hours. The excess TiCL is separated hot by filtration or sedimentation. TiCL treatment is repeated one or more times if the desired alcohol content is to be very low (usually less than 0.5% by weight).

When producing a catalytic component containing an electron-donor compound, it is added to TiCL in amounts equal to molar ratios relative to MgCL in

163 548 range 1: 4 to 1:20. After treatment with TiCU, the solid is washed with a hydrocarbon, for example hexane or heptane, and then dried.

According to another method, the molten adduct in the inert hydrocarbon emulsion is passed through a tube of suitable length in turbulent motion and then collected in the inert hydrocarbon kept at a low temperature. This method is described in U.S. Patent No. No. 4,399,054. In this case, the adduct particles are also partially dealcoholated and reacted with TiCl 2.

In a variant of the methods described above, the titanium compound, especially when it is solid at room temperature, such as, for example, TiCl 2, is dissolved in the molten adduct, which is then de-alcoholized as indicated above and reacted with a halogenating agent capable of reacting and separating hydroxyl groups, such as SiCU, for example.

In the initial molten adduct, co-agents such as AlCb, AlBr3, ZnCl2 may be present in addition to the titanium compound and optionally other transition metals.

Titanium compounds suitable for the preparation of catalyst components in addition to TiCl2 and T1Cl3 and similar halides also include titanium halohydroxides such as trichlorophenoxy titanium and trichlorobutoxytitanium.

Finally, the titanium compound can be used in meiszanines with other transition metal compounds such as V, Zr and Hf halides and halogen alcoholates.

As already indicated, the catalyst component may also contain an electron-donor compound (internal donor). This is necessary when the catalyst prepared using the catalyst component is to be used in stereoregular polymerization of olefins such as propylene, 1-butene and 4-methyl-1-pentene.

Electron donor compounds can be selected from ethers, esters, amines, ketones.

Preferred compounds are the alkyl, cycloalkyl and aryl esters of polycarboxylic acids such as phthalic and maleic acid and the ethers of the formula shown in the drawing wherein R1 and R11 are the same or different and represent alkyl, cycloalkyl or aryl radicals with 1-18 carbon atoms , R1 and R2 are the same or different and are alkyl radicals with 1-4 carbon atoms. Ethers of this type are described in U.S. Patent Application No. 3,592, 234, filed May 31, 1989.

Examples representing these compounds are n-butyl phthalate, diisobutyl phthalate, di-n-octyl phthalate, 2-methyl-2-isopropyl-1,3-dimethoxypropane, 2-methyl-2-isobutyl-1,3-dimethoxypropane, 2, 2-diisobutyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane. .

The data shown in the examples and description refers to the following properties, determined according to the methods indicated below.

MIL flow index according to ASTM-D 1238, MIE flow indicator according to ASTM-D 1238, MIF flow indicator according to ASTM-D 1238, xylene soluble fraction (see designation before examples) isotacticity index (II) - weight percentage of polymer insoluble in xylene in at 25 ° C. Basically this agrees with the weight percentage of polymer insoluble in boiling n-heptane.)

BET surface (Sorptomatic 1800 - C. Erba apparatus used) Porosity - unless otherwise specified, porosity is determined by the BET method. Calculates from the total pore distribution curve as a function of the pores themselves.

porosity (mercury) - determined by immersing a known amount of sample in a known amount of mercury inside a dilatometer and a gradual hydraulic increase in mercury pressure. The pressure for introducing mercury into the pores is a function of the pore diameter. The measurement is carried out using a porosimeter 2000 Series (C. Erba). The total porosity is calculated from the reduction of mercury volume and the pressure used.

flowability - flow time 100 g of polymer through a funnel whose outlet has a diameter of 1.25 cm and the walls are inclined at an angle of 20 ° C in relation to the vertical, morphology according to ASTM-D 1921—63 bulk density according to DIN-53194

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Determination of percentage soluble in xylene. 2 g of polymer is dissolved in 250 ml of xylene at 135 ° C with stirring. After 20 minutes, the solution is allowed to cool while stirring until the temperature reaches 25 ° C. After 30 minutes, the precipitated material is filtered through a filter, the solution is evaporated under a stream of nitrogen and the residue is dried in vacuo at 80 ° C until a constant weight is obtained. In this way, the percentage of xylene soluble polymer at room temperature is calculated.

Method for producing MgCL / alcohol adducts.

MgCk / alcohol adducts in the form of spherical particles are prepared as described in Example 2 of US Patent No. 4,399,054 using 3,000 rpm instead of 10,000 rpm.

The adduct was partially dealcoholized by heating at a temperature rising from 30 ° C to 180 ° C using a nitrogen flow.

Method for producing the solid catalyst component.

Into a liter flask equipped with a condenser and a mechanical stirrer, 625 ml of TiCU was added under a flow of nitrogen. At 0 ° C, 25 g of partially dealcoholized adduct was added under stirring. The mixture was then heated to 100 ° C for an hour and when the temperature reached 40 ° C, diisobutyl phthalate was added in a molar ratio Mg / DIBF = 8. The temperature was kept at 100 ° C for 2 hours, then the mixture was allowed to decant and the hot liquid was poured off. 550 mL TiCU was added and the mixture heated to 120 ° C for an hour. Finally, it was allowed to stand and the hot liquid was poured off. The residual solid was washed 6 times with 200 ml portions of anhydrous hexane at 60 ° C and 3 times at room temperature. Then the solid was dried in vacuo.

Polymerization of propylene.

Into a 41 stainless steel autoclave, equipped with a stirrer and a thermostat, which was degassed with nitrogen at 70 ° C for an hour and then with propylene, was introduced at 30 ° C without mixing but with a slight flow of propylene, a catalyst system suspended as part of the above solid catalyst component in 80 ml hexane, 0.76 g triethylaluminum and 8.1 mg diphenyldimethoxysilane (DPMS). The suspension was prepared immediately before the trial.

The autoclave was then closed and 1 Nl H2 was introduced. 1.2 kg of liquid propylene were placed under stirring and the temperature was adjusted to 70 ° C over 5 minutes, keeping it constant for 2 hours.

At the end of the test, mixing was stopped and unreacted propylene was removed. The autoclave was cooled to room temperature, the polymer was removed and dried at 70 ° C in a drier under nitrogen flow for 3 hours and then analyzed.

Copolymerization of ethylene with butene-1 (LLDPE).

The autoclave described above was degassed with propane instead of propylene. A 25 cm catalytic system was introduced into the autoclave³ hexane, 1.05 g triisobutylaluminum and the above catalyst component, at room temperature, with a slight flow of propane. The pressure increased by 0.54 MPa under the influence of H2, and then 0.19 MPa under the influence of ethylene. Prepolymerization was carried out at 45 ° C using 15 g of ethylene.

Propane 1 hydrogen was degassed and after washing with hydrogen wash the gas phase was formed from 37.0 g ethylene and 31.9 g butene-1 and hydrogen at 0.17 MPa pressure (total pressure 1.5 MPa).

Then a mixture of ethylene and butene-1 was fed in a 9: 1 weight ratio at 70 ° C for 2 hours.

Finally the autoclave was degassed and cooled quickly to room temperature. The resulting copolymer was dried at 70 ° C under nitrogen for 4 hours in an oven.

Polymerization of ethylene.

A 2.51 stainless steel autoclave equipped with a stirrer and thermostat was blown as described above for the propylene test using ethylene instead of propylene.

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At 45 ° C, a stream of hydrogen, 900 ml of a solution containing 0.5 g / l of triisobutylaluminum in anhydrous hexane was introduced, and immediately afterwards the catalyst component suspended in 100 ml of the solution described above.

The temperature was quickly brought to 70 ° C and hydrogen was fed until the pressure reached 0.29 MPa, followed by ethylene until the pressure reached 1 MPa. These conditions were maintained for 3 hours, replenishing ethylene continuously. At the end of the polymerization reaction, the autoclave was evacuated quickly and cooled to room temperature.

The polymeric suspension was filtered and the solid residue was dried under a stream of nitrogen at 60 ° C for 8 hours.

Example 1. Spherical MgCl 3 · EtOH adduct (obtained as described in the general method) was dealcoholated to an EtOH / MgCl2 molar ratio of 1.7.

A product with the following characteristics was obtained:

- porosity (mercury) = 0.904 cm ³/ G,

- specific surface = 9.2 m ²/ G,

- bulk density = 0.607 g / cm3.

From this adduct, by treatment with TiCl 2 as described in the general method, a catalyst component was obtained in the spherical form with the following characteristics:

- Ti = 2.5% by weight,

- DIBF = 8.2% by weight,

- porosity = 0.405 cm3 / g,

- specific surface = 249 m²/ G,

- bulk density = 0.554 g / cm³.

The X-ray spectrum of the component had no reflection at 14.95 °, while the halo was present with maximum intensity at 2 δ 34.72 °.

The catalyst component was used for the polymerization of propylene carried out as described in the general method. Using 0.01g of the catalyst component, 430g of polymer was obtained with the following characteristics:

- xylene soluble fraction at 25 ° C = 2.4%

- MIL = 2.5g / 10 '

- bulk density = 0.48 g / cm³ morphology: 100% spherical particles with a diameter of 100-5000pm, flowability: 10 seconds.

Example II By partial de-alcoholization (according to Example I) of the spherical MgCl2 · 3EtOH adduct also obtained according to the method indicated in Example I, an adduct with an EtOH / MgCk 1.5 molar ratio and the following characteristics was obtained:

- porosity (mercury) = 0.946 cm³/ G,

- specific surface area = 9.1 m2 / g,

- bulk density = 0.654 g / cm³.

From the adduct by treatment with TiCl 4 as described above, a spherical catalyst component was prepared with the following characteristics:

- Ti = 2.5% by weight,

- DIBF = 8.0% by weight,

- porosity = 0.389 cm³/ G,

- specific surface = 221 m²/ G,

- bulk density = 0.555 g / cm³.

The X-ray spectrum of the component shows no reflection at 2 0 14.95 ° C, only halo with maximum intensity at 2 0 2.5780 ° is present.

The catalyst component was used for propylene polymerization carried out as described in Example I.

Using 0.015 g of the catalyst component, 378 g of polypropylene were obtained with the following characteristics:

- xylene soluble fraction at 25 ° C = 2.6%,

MIL = 2.8g / 10 ',

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- bulk density = 0.395 g / cm,

- morphology = 100% of spherical particles with a diameter of 1 (0) 0-5000pm

- flowability - 12 seconds

Example III. By partial de-alcoholization (according to Example 1) of the spherical MgCl2'3EtOH adduct obtained according to the method described in the previous examples, an adduct with a molar ratio EtOH / MIgCU = 1 and the following characteristics was obtained:

- porosity (mercury) = 1.208 cm³/ G,

- specific surface area = 11.5 m2 / g,

- bulk density = 0.535 g / cm³.

From this adduct, by reaction with TiCl 2 described in previous examples, a spherical catalytic component was obtained with the following characteristics:

- Ti = 2.2% by weight,

- DIBF = 6.8% by weight,

- porosity = 0.261 cm³/ G,

- specific surface area = 66.5 m2 / g,

- bulk density = 0.440 g / cm³.

The x-ray spectrum of the catalytic component showed reflex at 14.95 ° as well as at 20-35 °.

Using 0.023 g of the catalyst component for propylene polymerization under the conditions given in Example 1, 1.412 g of polypropylene with the following characteristics were obtained:

- xylene soluble fraction at room temperature 3.0%

- MIL = 3.2g / 10 ',

- bulk density = 0.35 gW,

- morphology - 100% of spherical particles with a diameter of 500-5000pm,

- flowability - 12 seconds

By following the procedure described in the general procedure, ethylene-butene was copolymerized using 0.0238 g of the catalyst component. 240 g of copolymer were obtained with the following characteristics:

- bound butene = 8.3% by weight,

- xylene soluble fraction at room temperature = 12.2%,

- MIE = 12g / 10 ',

- MIF = 12g / 10 ',

- MIF / MIE = 30,

- morphology = 100% of spherical particles with a diameter of 500-5000 pm.

Example IV By partial de-alcoholization (according to Example I) of the spherical MgCl2 · 3EtOH adduct obtained as described in the previous examples, an adduct with an EtOH / Mg = 0.4 molar ratio was obtained, which had the following characteristics:

- porosity (mercury) = 1.604 cm³/ G,

- specific surface area = 36.3 m2 / g,

- apparent specific gravity = 0.310 g / cm³.

By treating this TiCU support at 135 ° C., 50 g / L, three times an hour, a spherical catalyst component was obtained, which, after removing excess TiCU, washing and drying, had the following characteristics:

- Ti = 2.6% by weight,

- porosity = 0.427 cm³/ G,

- specific surface area = 66.5 m2 / g.

The X-ray spectrum of this component showed reflex at 20,95 ° as well as at 2 0 35 °.

Using 0.012 g of the catalyst component in ethylene polymerization according to the general method described above, 400 g of polyethylene were obtained with the following characteristics:

- MIE = 0.144g / 10 ',

- MIF = 8.87g / 10 ',

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- MFI / MIE = 61.6,

- morphology = 100% spherical particles with a diameter between 100 and 5000μτη.

- flowability = 12 seconds

- apparent specific gravity = 0.38 g / cm³.

EXAMPLE. By partial de-alcoholization (as described in Example I) of the spherical MgCl2 · 3EtOH adduct prepared according to the method indicated in the previous examples, an adduct with an EtOH / MgCl2 molar ratio of 0.15 was obtained, which had the following characteristics:

- porosity (mercury) = 1.613 cm³/ G,

- specific surface area = 22 m²/ G,

The X-ray spectrum of this component showed reflex at 2 & 14.95 ° as well as at 2z> 35 °.

Using 0.03 g of this component in ethylene polymerization as described in Example IV, 380 g of polyethylene were obtained with the following characteristics:

- MIE = 0.205 g / 10 ',

- MIF = 16.42 g / 10 ',

-MIF / MIE = 80.1,

- flowability = 12 seconds

- bulk density = 0.40 g / cm³.

Example VI. The MgCL2 * 1EtOH adduct was prepared as described in Example III, but using the alcohol diluted water used to prepare the starting MgCl3 · EtOH, in an amount of 2% by weight.

The de-alcoholized adduct contained 20% water by weight. From this adduct, after treatment with TiCL₄ and diisobutyl phthalate (DIBF) as described in Example 1, a spherical catalyst component was obtained with the composition: Ti = 2.35%, DIBF = 6.9%.

Using 0.025 g of this component for propylene polymerization as described in Example 1, 410 g of polymer was obtained in the form of spherical particles having the following characteristics:

- xylene soluble fraction at 25 ° C = 3.1%,

- MIL = 3.0 g / 10 ',

- apparent specific gravity = 0.35 g / cm³,

- morphology = 100% of the spherical particles have a diameter between 100 and 5000μτη,

- flowability = 13 seconds

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