CS215014B2 - Catalytic system and method of preparation thereof - Google Patents

Description

The invention relates to a catalyst system and a process for its preparation. The catalyst system of the present invention is suitable for ethylene copolymerization using highly active complex catalysts containing magnesium and titanium in a gas phase process to produce ethylene copolymers having a density of from 910 * kg / m ³ inclusive to 940 kg / m ³ inclusive with a melt flow ratio as defined below) ranging from 22 inclusive to 32 inclusive.

Until recently, low density polyethylene (i.e., 940 kg / m ³ or less) has been industrially produced mostly by homopolymerization of ethylene at high pressure (i.e., 103 MPa and above) in the gas phase in stirred and long tubular reactors, in the absence of solvents and using free radical initiators. More than 450,000 tons of low density polyethylene are produced annually worldwide.

As recently disclosed in US Patent No. 4 0.11382 and Belgian Patent No. 839,380, it has been found that low pressure polyethylene can be industrially produced under a pressure below 6.87 MPa by gas phase reaction in the absence of solvents using certain catalysts. containing chromium and titanium (and optionally fluorine) and under specific operating conditions in a fluidized bed process.

However, the products produced by the methods described in the methods of U.S. Patent No. 4,011,382 and Belgian Patent No. 839,380 'have a relatively broad molecular weight distribution Mw / Mn, from 6 to 20 (including limit values). As such, they are well suited for numerous applications in the field of wire and cable insulation and hose production, but are not well suited for injection molding. They are also not widely used for the production of films, since films made from these resins have poor optical and mechanical properties.

In order to be useful in an industrial gas phase process, such as the fluidized bed process of U.S. Patent Nos. 3,709, 8.53, 4,003,712, and 4,011,382, Canadian Patent 991,798, and Belgian Patent No. 839,380, catalysts must have high activity, i.e., must have a productivity of at least 50,000 and preferably at least 100,000 kg of polymer per kg of catalyst metal or higher. This is because such processes in the gas phase typically do not employ any processes to remove catalyst residues. The catalyst residues in the polymer must therefore be so small that they can be left in the polymer without causing undesirable difficulties in the processing of the resins and / or their application to the end customer. Where highly aktiv215814 is used successfully

213014 of such catalysts in such fluidized bed processes, the heavy metal content of the resin is of the order of 20 ppm or less at a productivity of at least 50,000 or more, 10 ¹ ppm or less at a productivity of at least 100,000 or more and 3 ppm or less at a productivity. 300,000 or more. The low content of catalyst residues is also important when the catalyst contains chlorine-containing substances, such as titanium, magnesium and / or aluminum chlorides, used in so-called Ziegler or Ziegler-Natta catalysts. The high chlorine content of the molding resin can cause pitting and other corrosion of the metal surfaces of the molding equipment. A chlorine content of 200 ppm or higher is unacceptable for industrial production.

U.S. Patent No. 3,989,881 discloses the use of a highly active catalyst for a slurry process for producing ethylene polymers having a low molecular weight distribution Mw / Mn in the range of about 2.7 to 3.1. Attempts have been made to use catalysts similar to those described in U.S. Patent No. 3,989,881 in the production of narrow molecular weight polyethylene by polymerization of ethylene alone or in conjunction with propylene in a gas-phase fluidized bed process using apparatus and apparatus-like conditions, and The conditions described in U.S. Patent No. 4,011,382 and Belgian Patent No. 839,380. However, these attempts were unsuccessful. To avoid the use of solvents used in the slurry catalyst systems described in U.S. Patent No. 3,989,881, titanium and magnesium containing components were dried. The dried substance, however, was in the nature of a viscous, pyrophoric resin which could not be fed well into the reactor because it was not freely movable. Even when the agitator was mixed with silica and fed to the reactor in this form, industrially acceptable results were not achieved. The catalyst productivity was low or the catalyst was pyrophoric and difficult to handle, because the polymer product had a low bulk density, i.e., less than or equal to 97.3 kg / m ³ .

Polymers with such bulk density are not required from an industrial point of view because they are of a dusty nature; if the polymer is to be stored or sold in granular form, considerably more space is required to store and transport such products. Although the granular polymer is to be processed into pellets prior to shipping, processing such a large amount of low density substance in a pelletizer requires considerably longer processing times compared to the time to process the same amount of high density substance on the same extruder.

U.S. Patent No. 4,124,532 discloses the polymerization of ethylene and propylene using highly active catalysts. These catalysts include complexes which may contain magnesium and titanium. Said complexes are prepared by reacting a halide of formula MX.9 (where M may be magnesium) with a compound of formula M‘Y (where M * may be titanium and Y a halogen or an organic residue) in an electron-norine compound. These complexes are then isolated by either crystallization, solvent evaporation or precipitation.

The polymerization is carried out using these catalytic co-complexes and an alkyl-aluminum compound.

U.S. Patent No. 4,124,532, however, does not disclose any special technique or methods of preparing catalysts to achieve the desired results in the process of the invention described in these teachings. The use of the catalysts disclosed in U.S. Patent No. 4,124,532 without these special methods would not result in an industrial fluidized bed process suitable for the production of polyethylene on an industrial scale. In addition, examples.

they do not disclose the practical method of copolymerization suitable for the production of special low density copolymers having the preferred morphology of the invention described in these references.

U.S. Pat. Nos. 3,922,322 and 4,035,560 disclose the use of several titanium and magnesium-containing catalysts for the production of granular ethylene polymers by a gas-phase fluidized bed process at pressures below 20 psig. However, the use of these catalysts in these processes has considerable disadvantages. Using the catalyst of U.S. Pat. No. 3,922,322, polymers having a very high content of catalyst residues, i.e., a residue of about 10-0 ppm-Ti and greater than about 300ppm Cl, are obtained as shown in the exemplary embodiment of this patent. Besides, how. No. 3,922,322, the catalyst is used in the form of a prepolymer, and very high volumes of catalyst composition need to be charged to the reactor. The preparation and use of this catalyst therefore requires the use of relatively, very large equipment for its production, storage and transport.

Also, using the catalysts of U.S. Pat. No. 4,035,560, polymers containing high amounts of catalyst residues are obtained and the catalyst compositions used are obviously pyrophoric, as is apparent from the types and amounts of reducing agents used in these catalysts.

No. 892,325, filed Mar. 31, 2004. 1978 (authors: FJ Karo-1 et al., Title: Preparation of copolymers of ethylene in a fluidized bed), discloses that ethylene copolymers having a density of 910 to 960 kg / m ³ , with a melt flow rate ratio (defined below) of 22 to 32, including limit values, and with a low catalyst residue content can be produced in granular form at relatively high productivity by either monomer or mo219014.

They are polymerized with the monomers in a gas phase process using a specific, highly active complex catalyst comprising magnesium and titanium, which is mixed with an inert carrier. The granular polymers thus produced have excellent physical properties which allow them to be used extensively as resin molding. However, these polymers have several disadvantages. First of all, since the catalyst comprises a carrier which is not removed from the polymer before it is formed, polymers containing some of these carriers are not very suitable for producing clear films. Carrier particles can impair the properties of clear films made from these polymers. Second, these polymers, especially those having a lower density, have a relatively low bulk density. The processing of these polymers therefore requires the use of larger volumes during transport and storage than is the case with pelletized products which the processing industry is used to. This leads to the need for greater capital investment in the equipment needed to handle and store these low density granular materials. In addition, the dispensing of low density granular substances into the molding and extruder requires a longer dosing time than is the case for dispensing the same weight of the pelletized substance, since a larger volume of the granular substance must be processed. Third, the polymer particles formed during fluidized bed polymerization have an irregular shape and are somewhat difficult to float. The resulting product also contains a relatively high number of dusty particles, i.e. particles of 150 µm or less.

It has now unexpectedly been found that ethylene copolymers with a wide density range of 910 to 940 kg / m ³ and a melt flow rate ratio of 22 to 32, including limit values having a relatively low catalyst residue content and a relatively high bulk density, can be used. provide films with good clarity, to produce at high productivity suitable for industrial production by gas-phase copolymerization of ethylene with one or more C5 to C8 alpha olefins in the presence of a highly active catalyst of the invention containing a magnesium-titanium complex described below prepared under specific conditions activation with an organoaluminum compound, impregnated with a porous inert carrier. The copolymers produced using the catalytic system have a bulk density of 308 to 503 kg / m ³ , their particles have a rounded face and are more easily floating in the fluidized bed and contain relatively small amounts of fines.

Using the catalyst system of the present invention, copolymers can be prepared containing, as the main molar portion, ethylene (190 ° / o) and as the minor molar portion (1010 ° / o), one or more C 3 -C 6 α-olefins which should not contain any branches on any of its carbon atoms that is closer to the copolymer backbone than the fourth carbon atom. If one C3-C6 alpha-olefin is used, copolymers are obtained, if more C3-C8 alpha-olefins are used, or terpolymers are obtained and the like. Such alpha-olefins include propylene, 1-butene, 1-pentene, 1-hexene. , 4-methyl-1-pentene, 1-heptene and 1-octene. Preferred α-olefins are propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.

The copolymers have a melt flow rate ratio of from 22 to 32, preferably from 25 to 30, including limit values. The melt flow rate ratio is another way of characterizing the molecular weight distribution of a polymer. A melt flow rate (MFR) of 22 to 32 (including cut-offs) corresponds to a Mw / Mn in the range of about 2.7 to 4.1 and an MFR of 25 to 30 (including cut-offs) corresponds to a Mw / Mn ratio of about 2.8 to 3.6.

The copolymers have a density of about 910 to 940, preferably 917 to 935 kg / m ³ , including limit values. The density of the copolymer at a given melt index can be controlled primarily by the amount of C3 to Ce comonomer to be copolymerized with ethylene. In the absence of a copolymer, ethylene would homopolymerize with the catalyst of the invention to form homopolymers having a density of about 0.96. The addition of increasing amounts of comonomers to the polymers results in a gradual decrease in the density of the copolymer. Under the same reaction conditions, the amount of each of the various C3 to C8 comonomers needed to achieve the same result varies from monomer to monomer.

To achieve the same results, i.e. the same density at a certain melt index, increasing molar amounts of comonomers in the series C3 > C4 > Cs >

the melt index of the polymers is dependent on its molecular weight. The relatively high molecular weight polymers have a relatively low melt index. Ultra-high molecular weight ethylene polymers have a melt flow index at a higher load (HLMI of about 0.0 and very high molecular weight polymers have a melt flow index at a higher load of about 0.0 to about 1.0. Such high molecular weight polymers are difficult to form in The copolymers produced using the catalyst system of the present invention, on the other hand, are easily formed in such an apparatus. They have a melt flow index under normal load (MI j in the range of> 0.0 to about 100, preferably in the range of from about 0.5 to about 80, and at a higher load (MLMI of about 11 to about 2000). The melt index of polymers produced using the catalyst system of the present invention is dependent on the combination of polymerization reaction temperature, copolymer density and hydrogen / monomer ratio in the reaction. The melt flow index increases as the polymerization temperature increases In addition to hydrogen, other chain transfer agents, such as dialkyl zinc compounds, may also be used to further increase the melt index of the copolymers.

The produced copolymers contain g 1 and usually and 0.1 to g 0.3 C = C double bonds per 1000 carbon atoms and have a n-hexane extractable content (at 50 ° C) of less than about 3% and preferably less than about 2 % by weight.

The copolymers produced using the catalyst system according to the invention contain as catalyst residues of the order of from 0 to 20 ppm Ti inclusive at a productivity of 50,000 or higher, from 0 to 10 ppm inclusive at a productivity of 100,000 or higher and 0 to 3 ppm inclusive at a productivity of 300 OOO or higher. With respect to residues Cl, Br, or I, the content of these elements in the copolymers depends on their content in the catalyst precursor. From the ratio of titanium to chlorine, bromine or iodine in the original precursor, the chlorine, bromine or iodine residue content can be calculated based on the known productivity value relative to the titanium residue itself. Many copolymers produced using only chlorine-containing catalyst system components (Cl / Ti = 7) can calculate chlorine residues in the range of 0 to 140 ppm inclusive at a productivity of 50,000 · or greater, from 0 to 70 ppm inclusive at a productivity of 100,000 or higher and from 0 to 20 ppm at a productivity of 300,000 no bo higher. Copolymers are easy to produce at productivity rates of up to about 500,000.

The copolymers produced are granules! substances having an average particle size of the order of about 0.127 to about 1.78 mm, and preferably about 0.5 to about 1 mm. The particle size is important for the easy fluidization of the polymer particles in the fluidized bed reactor as described below. The copolymers have a bulk density of from about 308 to about 503 kg / m ³ .

The copolymers produced using the catalyst system according to the invention are suitable not only for the production of films, but also for other forming applications.

SUMMARY OF THE INVENTION The present invention provides a catalyst system consisting of a precursor of formula (I)

Mg _m Tii (OR) _n X _p [ED] _and where represents

ED electron donor compound, m number · from 0.5 to 56, preferably from 1.5 to including limit values, n number 0, 1 or 2, p number from 2 to 116, preferably from 6 to 14, including limit values, q a number from 2 to 85, preferably from 4 to 11, including limit values,

R a C 1 -C 14 aliphatic or aromatic hydrocarbon radical or a radical of formula COR COR, wherein R * represents a C 1 -C 14 aliphatic or aromatic hydrocarbon radical, and

X chlorine, bromine or iodine or a mixture thereof, which is impregnated into a porous support and is either not activated or partially activated by not more than 10 moles of activating compound per mole of titanium contained in the precursor, or fully activated> 10 to 400 moles of activating compound per mole of titanium contained in a precursor, wherein the activating compound is a compound of formula

Al (R 'j _c X' _d H _c where

X ‘represents chlorine or a group of the formula OR 'and each symbol

R "and R" ', which are the same or different, represent a C 1 -C 14 saturated hydrocarbon radical, d is a number from 0 to 1.5 e is a number of 1 or 0, the sum of c + d + e being 3, and the electron donor compound is a liquid organic compound in which the precursor is soluble, selected from the group consisting of alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones.

According to the invention, a catalyst system as defined above is prepared by:

I will prepare a precursor of the formula Mg _m Ti, (OR) _n X _p [ED] _q where is

ED electron donor compound, m number from 0.5 to 56 including limit values, n number 0, 1 or 2, p number from 2 to 116 including limit values, q number from 2 to 85 including limit values,

R a C 1 to C 14 aliphatic or aromatic hydrocarbon radical or a radical of formula COR ‘, wherein R‘ represents a C 1 to C 14 aliphatic or aromatic hydrocarbon radical, and

X chlorine, bromine or iodine, or a mixture thereof, by dissolving at least one magnesium compound and at least one titanium compound in at least one electron donor compound to form a solution of the precursor in the electron donor compound, and then isolating the precursor from said solution, is used a compound of the general formula

MgX2 where

X is as defined above, the compound of the general formula is used as the titanium compound

Ti (OR) _a X _b where a is a number 0, 1 or 2 and b is a number 1 to 4 inclusive, wherein the sum of a + b is 3 or 4 and R and X are as defined above, and liquid electron donor compounds are liquid organic compounds in which said magnesium compound and titanium compound are soluble selected from the group consisting of alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones, wherein the magnesium compound, titanium compound and electron donor compound are used in amounts such that it suited the meaning of the symbols m, n, paq, then

B) a porous support is impregnated with a precursor either prior to the isolation or after isolation from the solution of the electron donor compound, then optionally

C) the precursor partially activates not more than 10 moles or completely activates> 10 to 40 moles of activating compound per mole of titanium contained in the precursor, using the compound of the general formula as activating compound

Al (R ') _c X' _d H _e where

X ‘represents chlorine or a group of the formula OR" ‘and each symbol

R "and R" ', which are the same or different, represent a C 1 to C 12 saturated hydrocarbon radical, d is a number Ό to 1.5 e is a number · 1 or 0, with the sum c + d + e having the value 3 wherein the activation is performed after isolating the precursor impregnated in the porous carrier from the solution of the precursor in the electron donor compound.

Titanium compounds of the general formula Ti (OR) _and X _b can be used singly or in mixtures and include compounds of the formulas

T1CI3, T1C14, Ti (OCH3) Cl3, Ti (OC ₆ H 5) Cl 3, Ti (OCCOH3) Cl3 and TifOCOCeHsjCb.

The magnesium compounds of the formula MgX 2 can be used singly or in combination and include compounds of the formulas MgCl 2, BgBre and MgL 4. Of the magnesium compounds, anhydrous magnesium chloride is particularly preferred.

In the preparation of the catalysts used in the process of the invention, about 0.5 to 56, preferably about 1 to 10 mol, of the magnesium compound are used per mole of titanium compound.

The titanium compound and the magnesium compound are conveniently used in a form which facilitates their dissolution in the electron donor compound as described below.

The electron donor compound is an organic compound that is liquid at 25 ° C and in which the titanium compound and the magnesium compound are soluble. Electron donor compounds are known either under this name or under the name of the Lewis base.

By electron donor compounds are meant such compounds as alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones. Of these electron donor compounds, alkyl esters of C 1 to C 1 aliphatic carboxylic acids, alkyl esters of C 2 to C 5 aromatic carboxylic acids, C 2 to C 5, and preferably C 3 to C 1 aliphatic ethers, C 3 to C 1 cyclic ethers and preferably C 1 to mono or diether to C 3 and preferably C 3 to C 1 aliphatic ketones. Most preferred of these electron donor compounds are methyl formate, ethyl acetate, butyl acetate, ethyl ether, hexyl ether, tetrahydrofuran, dioxane, acetone and methyl isobutyl ketone.

The electron donor compounds can be used singly or in mixtures.

About 2 to 85 and preferably about 3 to 10 moles of the electron donor compound are used per mole of titanium.

The activating compounds may be used singly or in combination and exemplified by compounds of the formula

Al (C2HS) 5 Al (C2H5) 2Cl, Al (i-CiHa) ₃ , Al2 (C2H5) 3Cl3, Al (Ci-CiH9) 2H, Al (C6Hi3) 3, Al (C8H17) 3, A1 (C2H5) 2H and A1 (C2 H5) 2 (OC5 H5).

About 10 to 400 moles and preferably about 10 to 100 moles of activating compound per 1 mol of titanium compound are used in the activation of the catalysts used in the present invention.

Substances used as carriers are particulate solid porous substances which are inert to the other components of the catalyst composition and to the other active components of the reaction system. These carriers include inorganic materials such as silica and / or alumina. The carriers are used in the form of dry powders having a mean particle size of about 10 to 250, preferably about 50 to 150 µm. They are also porous and have a specific surface area of at least 3 and preferably at least 50 m ² / g. Catalyst activity or productivity is also improved when the silica has pores of at least 8 nm and preferably at least 10 nm and greater. The carrier should be dry, ie not contain absorbed water. The carrier is dried by heating to a temperature of at least 600 ° C. Alternatively, the carrier may be dried at a temperature of at least 200 ° C and then treated with 1-8% by weight of one or more of the alkyl aluminum compounds described above. This modification of the support with alkyl-aluminum compounds provides a catalyst system with increased activity, and using such a catalyst system, the resulting polymer particles also have improved morphology.

The precursor is prepared by dissolving the titanium compound and the magnesium compound in the electron donor compound at a temperature of about 20 ° C to about the boiling point of the electron donor compound. The titanium compound may be added to the electron donor compound before or after the addition of the magnesium compound, or simultaneously with the addition thereof. Dissolution of the titanium compound and the magnesium compound can be aided by stirring and, in some cases, heating the two compounds in the electron donor to reflux. After dissolution of the titanium compound and the magnesium compound, the precursor can be isolated by crystallization or precipitation of a C 5 -C 8 aliphatic or aromatic hydrocarbon such as hexane, isopentane or benzene.

The crystallized or precipitated precursor may be isolated in the form of fine, free-moving particles having a mean size of about 10 to 100 microns and a bulk density of about 202 to about 535 kg / m ³ .

The carrier is then impregnated with a carrier in a weight ratio of about 0.033 to 1 and preferably 0.1 to 0.33 parts of precursor per 1 part of carrier.

Impregnation of the dried (activated) carrier with the precursor can be carried out by dissolving the precursor in an electron donor compound and then mixing the resulting solution with the carrier. When the carrier is impregnated with the precursor, the solvent is evaporated by drying at a temperature of not more than 70 ° C.

The carrier can also be impregnated with a precursor by adding it to a solution of the raw materials used to prepare the precursor in the electron donor compound. In this case, the precursor is not isolated from the solution. The excess electron donor compound is then removed by drying or washing and drying at a temperature of not more than 70 ° C.

In order to be used in the process according to the invention, the precursor must be fully or partially activated, i.e. it must be treated with a sufficient amount of the activating compound to bring the titanium atoms contained in the precursor into active state.

In the preparation of the useful catalyst, it is necessary to carry out the activation such that at least the last activation stage is carried out in the absence of a solvent, so that the fully active catalyst does not need to be dried to remove the solvent. Two approaches have been developed to achieve this.

According to a first procedure, the precursor is completely activated outside the reactor in the absence of solvent by mixing the impregnated precursor dry with the activating compound. In this dry mixing, the activating compound is used in the soaked state in the carrier. The fully activated precursor is prepared in this process without the need for the catalyst system to be heated above 50 ° C before being fed into the polymerization reactor.

According to a second preferred method, the precursor is partially activated outside the polymerization reactor with an amount of activating compound to obtain a partially activated precursor in which the molar ratio of activator to titanium is up to about 10: 1 and preferably about 4 to 8: 1 . This partial activation is preferably carried out in a hydrocarbon solvent suspension. The resulting product is then dried to remove the solvent, at a temperature of -20 to 80, preferably 50 to 70 ° C. The resulting product has the character of a free-flowing particulate matter and can be readily introduced into the polymerization reactor. The partially activated precursor can be fed to a polymerization reactor in which activation by an additional activator, which may be the same or another compound, is completed.

The additional activator compound and the partially activated impregnated precursor are preferably fed to the reactor via separate lines. The additional activating compound may be injected into the reactor as a solution in a hydrocarbon or mineral oil. This solution typically contains about 2 to 30% by weight of the activating compound. The additional activator compound is added to the reactor in an amount such that at least 10 to 400, and preferably at least 15 to 60, a total molar ratio of Al / Ti is present in the reactor together with the amounts of activator compound and titanium compound listed as partially activated and impregnated precursors. the amount of activating compound introduced into the reactor reacts with the partially activated impregnated precursor and completes the activation of the titanium compound directly in the reactor.

In a continuous gas phase process such as the fluidized bed process described below, separate batches of partially or fully activated precursor impregnated in the carrier are continuously introduced into the reactor during polymerization, optionally with separate batches of additional activating compound needed to complete the batch. activation of the partially activated precursor, thus replacing the active sites of the catalyst that were consumed during the reaction.

The polymerization is carried out by contacting the monomer stream in the gas phase, for example in the fluidized bed process described below, substantially in the absence of catalytic poisons such as moisture, oxygen, carbon monoxide, carbon dioxide and acetylene, with a catalytically effective amount of fully activated a precursor (catalyst) impregnated on a support; pressure and temperature sufficient to initiate polymerization.

In order to achieve the desired density range of the copolymers, copolymerization with ethylene requires a sufficient amount of carbon chain comonomers of 3 or more carbon atoms to have a C 3 -C 6 comonomer content of the copolymer of 1.0 to 15 moles. %. The amount of comonomers required to reach the comonomer mol. The percentage required in the copolymer of this result depends on the particular comonomers or comonomers used.

The following table lists several different comonomers that can be used for copolymerization with ethylene to produce polymers having a density within the desired range at any given melt index. The table shows both the amount of comonomers needed in the copolymer to achieve these properties, and the required comonomer concentration in moles. % in the monomer gas stream that is fed to the reactor.

mol. % needed in the propylene gas stream

1-butene

1-pentene

1-hexene

1-okten

3.0 to 10 2.5 to 7.0 2.0 to 6.0 1.0 to 5.0 0.8 to 4.5

0.2 to 0.9 0.2 to 0.7 0.15 to 0.45 0.12 to 0.4 0.10 to 0.35

A fluidized bed reaction system that can be used is illustrated in Figure 1.

The reactor 10 consists of a reaction zone 12 and a speed reducing zone 14.

Reaction zone 12 comprises a bed of growing polymer particles, formed polymer particles, and a minor amount of catalyst fluidized by a continuous flow of polymerizable and modifying gaseous components consisting of make-up gas and gas recycled to the reaction zone. In order to maintain the fluidized bed in a fluidized state, the gas mass flow rate through the bed must be greater than the minimum flow rate required for fluidization. Preferably, the gas mass flow rate through the bed is about

1.5 to about 10X higher, preferably about 3 to 6X higher than the minimum gas mass flow rate required for fluidization (Gmf). The Gmf designation for the minimum gas mass flow rate required to achieve fluidization was suggested by C. Y. Wen and Y.H. Yu, "Mechanics of Fluidization," Chemical Engineering Progress Symposium Series, Vol. 62, pp. 100-111 (1966).

It is important that the bed always contain particles that prevent "hot spots" and that trap and distribute the pulverulent catalyst in the reaction zone. Upon commencement of operation, a polymeric particle is usually introduced as a base into the reaction zone before the gas stream is introduced. These particles may be identical to the polymer formed or may be different. When different, they are drawn off with the resulting polymer particles as a leading product. Finally, the fluidized bed of the desired polymer particles displaces the starter bed.

The partially or fully activated precursor (catalyst) used in the fluidized bed is preferably stored in a standby container 32 under an atmosphere of an inert gas such as nitrogen or argon,

Fluidization is achieved by a high rate of gaseous recycle introduced into and through the bed, which is typically of the order of about 50 times higher than the rate of make-up gas. The fluidized bed usually looks like a dense mass of moving particles flowing in the free vortex created by the passage of gas through the bed. The pressure drop across the bed is equal to or somewhat higher than the weight of the bed divided by the cross-section of the bed, so it is dependent on the reactor geometry.

The make-up gas is introduced into the bed at the same rate as the withdrawal rate of the polymer product particles. The make-up gas composition is determined by an analyzer 16 located above the bed. The gas analyzer determines the loss of components in the gas to be recycled and the composition of the make-up gas is adjusted accordingly to keep the composition of the gaseous mixture substantially steady state in the reaction zone.

In order to ensure complete fluidization, the recycle gas and possibly part of the make-up gas is fed into the reactor via an inlet 18 under the bed. Above the inlet 18 there is a gas distribution plate 20 which assists fluidization of the bed.

The portion of the gaseous stream which does not react in the bed forms recycled gas, which is discharged from the polymerization zone preferably by passing through a zone 14 located above the bed in which the velocity is reduced and the entrained particles fall back into the bed. Particle separation may be aided by the inclusion of a cyclone 22, which may either be part of or outside the speed reducing zone 14. If necessary, the recycle gas can then be passed through a filter 24 which is adapted to separate small particles therein at high flow rates and to prevent dust from depositing on the heat transfer surface and on the compressor sheets.

The recycle gas is then compressed in a compressor 25 and passed through a heat exchanger 26 where it is freed from the reaction heat before returning to the bed. By constantly removing the heat of reaction, there is no apparent temperature gradient in the upper part of the bed. A temperature gradient exists in the lower 152 to 304 mm bed, between the inlet gas temperature and the bed rest temperature. It has been observed that the bed almost immediately adjusts the temperature of the recycle gas above the 1.52 to 304 mm bed zone to the bed temperature value so that the bed temperature is substantially constant under steady state conditions. The recycle gas is fed to the bottom of the reactor via an inlet 18 and into the fluidized bed through a distributor plate 20. The compressor 25 may also be placed upstream of the heat exchanger 28.

The distributor plate 20 plays an important role in the operation of the reactor. The fluidized bed contains both growing and formed polymer particles and catalyst particles. Since the polymer particles are hot and possibly active, they must be prevented from settling, since if any calm mass is formed, the active catalyst contained in these particles could cause the reaction to continue and the particles would melt due to the heat generated. It is therefore important that the recycle gas is passed through the bed at a rate sufficient to fluidize the particles at the bottom of the bed. The bottom of the bed is formed by a separating plate 20 and may be a sieve, a plate with slits, a perforated plate, a plate with caps (analogous to the distillation column trays) and the like. All parts of the plate may be stationary or of a movable type such as as described in U.S. Patent No. 3,298,792. Whatever the design of the plate, the plate must disperse the recycle gas between the particles at the bottom of the bed and maintain it in a fluidized state. The board also aims to support a quiet bed of resin particles when the reactor is not in operation. The movable portions of the plate may be used to extrude polymer particles retained on or within the plate.

Hydrogen can be used as the chain transfer agent in the polymerization. The hydrogen / ethylene molar ratio that can be used is in the range of about 0 to about 2.0 moles of hydrogen per mole of monomer in the gas stream.

Any gas inert to the catalysts and reactants may also be present in the gas stream. The activator compound is preferably added to the gas recycle system in its hottest part. Preferably, therefore, the activator is introduced into the recycle line downstream of the heat exchanger, such as from the reservoir 27 through line 27A.

In addition to hydrogen, the compounds of the formula I can be used in addition to hydrogen as molecular weight control agents, i.e. as chain transfer agents.

Zn (R _a ) R _b where

R _a and R _b are the same or different C 1 -C 14 aliphatic or aromatic hydrocarbon radicals.

This further increases the melt index values of the produced copolymers. About 0 to 50, and preferably about 20 to 30 moles of zinc compound (calculated as Zn) per mole of titanium compound (calculated as Ti) can be added to the gas stream introduced into the reactor. Zinc compound would be introduced into the reactor preferably in the form of a dilute solution (concentration 2-10 ^I0 / weight percent) in hydrocarbon solvent or absorbed on a solid diluent material, such as silica, in amounts of about 10 · to 50% % by weight. These substances are often pyrophoric. The zinc compound may be fed to a recycle gas stream from the metering device adjacent the metering device 27.

The fluidized bed reactor must operate at a temperature below the sintering temperature of the polymer particles. In order to prevent sintering of the particles, the working temperature must be below the sintering temperature. The production of ethylene copolymers by the process of the invention is preferably carried out at a temperature of about 30 to about 106 ° C, most preferably at a temperature of 75 to 95 ° C. Temperatures of about 75 to 95 ° C are used to produce products with a density of about 910 to 920 kg / m ³ and temperatures of about 80 to 100 ° C for production of products with a density of about 920 to 940 kg / cm ³ .

The fluidized bed reactor is operated at a pressure of up to about 200 psig, preferably at about 10 psig to about 400 psig, and when operating at higher pressures in this range, heat transfer is facilitated since the pressure rise is as a result of an increase in the unit volume heat capacity of the gas.

A partially or fully activated precursor is injected into the bed at a rate equal to the rate at which it is consumed by an inlet 30 positioned above the manifold plate 20. An important feature of the invention is that the catalyst is injected at a point above the manifold plate. Since the catalysts used according to the invention are highly active, injection into the space below the distributor plate could result in polymerization being initiated at this point, which could eventually lead to blockage of the distributor plate. Injection of the catalyst into the fluidized bed, in turn, aids in the distribution of the catalyst in the bed and avoids the formation of sites with a high catalyst concentration which could lead to hot spots.

A gas inert to the catalyst, such as nitrogen or argon, is used to introduce the partially or fully reduced precursor and any non-gaseous activating compound or transfer agent into the bed.

Bed productivity is controlled by catalyst injection rate. Bed productivity can simply be increased by increasing the catalyst injection rate and reduced by reducing the catalyst injection rate.

Since any change in catalyst injection rate results in a change in reaction heat evolution rate, the recycle gas temperature is adjusted up or down to adjust the reaction heat evolution rate, the recycle gas temperature is adjusted up and down to adjust the heat evolution rate. This ensures a substantially constant temperature in the bed. Of course, both the fluidized bed and the recycle gas cooling system must be equipped with appropriate bed temperature detection devices and a cooling system to allow the operator to appropriately adjust the temperature of the recycle gas.

Under a certain combination of operating conditions, the fluidized bed is maintained at substantially the same height by withdrawing a portion of the bed as product at the same rate as the rate of particle formation of the polymer product. Since the rate of heat evolution is directly proportional to product formation, the rate of increase in gas temperature along the reactor (i.e., the temperature difference between the inlet gas temperature and the outgoing gas temperature) determines the rate of polymer particle formation at a constant gas velocity.

Preferably, the polymer product particles are collected continuously through a conduit 34 or near the distributor plate 20. The particles are collected in the form of a suspension with a portion of the gaseous stream vented prior to settling to prevent further polymerization and caking before the particles reach the zone where are gathering. The suspending gas can also be used to transfer the product from one reactor to another.

The polymer product particles are expediently and preferably removed by means of two sequentially operated time-adjusted valves 36 and 38 between which a separation zone 40 is provided. When the valve 38 is closed, the valve 36 is opened so that it permits the gas / product mixture to pass into zone 40. the valve 38 is opened to transfer the product to the outer insulating zone. The valve 38 is then closed and closed until the next product withdrawal.

Finally, the fluidized bed reactor is equipped with a suitable venting system that allows venting at start-up and shutdown. The reactor does not require the use of any mixing devices and / or wall scraping devices.

The supported catalyst system of the present invention provides a fluidized bed product having a mean particle size of about 0.25 to 1.78 mm, preferably between about 0.45 to 0.90 mm, with the support catalyst residues in the polymer being unusually small. In the fluidized bed process, the polymer particles are relatively easy to float. The polymer product contains a relatively small amount of dusty particles (less than 150 (Um)), i.e. less than 4% by weight.

The feed monomer gas stream, optionally with inert gaseous diluents, is fed to the reactor at a rate to provide a space / time yield of about 32.4 to about 162.1 kg / h / m ³ of bed volume.

The term "crude resin or polymer" as used herein refers to a polymer in granular form as obtained from a polymerization reactor.

The following examples serve to illustrate the invention in more detail, but do not limit the scope thereof in any way.

The properties of the polymers produced in the examples are determined by the following test methods:

Density

A test plate is made and tempered at 100 ° C for 1 hour to approach equilibrium crystallinity. The density measurement is then performed in a density gradient column.

Melt Flow Index (MI)

ASTM D-1238 Condition E-Measured at ^180: C, data g for 10 'minutes.

Flow rate (melt flow index at higher load)

ASTM D-1238-Condition F, The measurement is performed using ten times the load index of the melt index.

W ^{r i Ch i} ° ^Sti ₌ flow rate melt flow index

Productivity

A sample of the resin product is ashed and the weight% ash is determined, since the ash is essentially a catalyst. The productivity is therefore expressed in kg of polymer produced per kg of total catalyst consumed. The amount of titanium, magnesium and chlorine in the ash is determined by elemental analysis.

Density

The resin is poured into a 100 ml graduated cylinder through a funnel with a 9.5 mm stem diameter up to the 100 ml mark. Do not shake the cylinder during filling. The weight difference is determined by weighing.

Molecular weight distribution (Mw / / Mn)

It is determined by gel chromatography on

Styrogel with a pore size sequence of 10 ⁶ , 10 ⁴ , 10 ³ , 10 ² , 6 nm. Perchlorethylene at 117 ° C is used as solvent. Detection is performed by infrared radiation at 3.45 μΐη. Movie rating

The film sample is monitored with the naked eye to determine the size and distribution of the gel-like particles or other foreign particles as compared to a standard film sample. The appearance of the film is compared with standard samples and rated from a scale of -100 (very poor film) to +100 (excellent film).

Substances extractable with n-hexane (FDA-test, used for polyethylene films intended to come into contact with food). The sample film thickness of 0.038 mm and a surface of 1230 cm ² was sprayed on strips measuring 2 cm -54X15,24 and weigh to the nearest 0.1 mg. The strips were placed in a flask and extracted with 300 ml of n-hexane at 50 + 1 ° C for 2 hours. The extract is then decanted into a balanced culture dish. After drying the extract in a vacuum desiccator, the culture dish is weighed to the nearest 0,1 mg. The amount of extract calculated on the original sample weight is then reported as the weight fraction of the n-hexane extractable substances.

Unsaturation

Measurements are performed using an infrared spectrophotometer (Perkin Elmer Model 21). Resins of 0.635 mm thickness are made from the resin and serve as test specimens. Absorbance is measured at 10.35 μΐη for transvinylidene unsaturation, at 11.0 µm for terminal wave unsaturation and at 11.25 μΐη for vinylidene unsaturation in the side chains. Absorbance per 1 mm of thickness of the compact is directly proportional to the multiple of the concentration of unsaturation and absorbency. Absorbency values are taken from the literature (R. J. de Kock, et al., J. Polymer Science. Part B, 2, 339 (1964)).

Example I a

Preparation of impregnated precursor

A 12 L flask equipped with a mechanical stirrer was charged with 41.8 g (0.439 mol) of anhydrous magnesium chloride and 2.5 L of tetrahydrofuran (THF). To this mixture was added dropwise 27.7 g (0.184 mol) of titanium tetrachloride over 1/2 hour. It may be necessary to heat the mixture at 60 ° C for about 1/2 hour to completely dissolve the substance.

The precursor can be isolated from the solution by crystallization or precipitation and then analyzed for magnesium and titanium, since some of the magnesium and / or titanium compound may have been lost in the precursor isolation. The empirical formulas used herein to characterize the precursor composition are derived provided that magnesium and titanium still exist in the form of compounds that were originally added to the electrodonor compound. The amount of electron donor compound is determined by chromatography.

To the above solution is added 500 grams of porous silica, dried at a temperature of up to 800 ° C and optionally treated with 4-8% by weight of triethyl aluminum, and the mixture is stirred for 1/4 hour. The mixture was purged with nitrogen at 60 ° C for about 3-5 hours. A dry, free-flowing powder is obtained having a particle size equal to the silica particles used. The absorbed precursor has a composition corresponding to the formula

TiMg, oClio (THF) ₆ . ₇ Example I b

Preparation of the impregnated precursor from a preformed precursor

Dissolve 146 g of precursor in a 12 L flask equipped with a mechanical stirrer

2.5 L of dry THF. The solution may be heated to 60 ° C to facilitate dissolution. 500 g of porous silica are added and the mixture is stirred for 1/4 hour. The mixture is then dried by flushing with a nitrogen stream at a temperature of up to 60 ° C for about 3 to 5 hours. A dry, free-flowing powder is obtained having a particle size equal to that of the silica particles.

Example II

Activation procedure

The required weight of impregnated precursor and activating compound is placed in a mixing drum together with a sufficient amount of an anhydrous aliphatic hydrocarbon diluent such as isopentane to form a suspension.

The activator compound and the precursor are used in amounts to provide a partially activated precursor having an Al / Ti ratio greater than 0 but less than 10 or equal to 10. The preferred ratio is 4 to 8: 1.

The suspension is stirred vigorously at room temperature and at atmospheric pressure for a period of time. 1/4 to 1/2 hour. The resulting suspension is dried under a stream of dry inert gas, such as nitrogen or argon, at atmospheric pressure and at a temperature of 65 + 10 ° C to remove the hydrocarbon diluent. This usually takes about 3 to 5 hours. The resulting catalyst is in the form of a partially activated precursor impregnated in the pores of silica. The substance is in the form of a freely movable-powdered material. The particles of 21014 correspond to the size and shape of the silica particles. The product is not pyrophoric if the alkyl aluminum content is up to 10% by weight. It is kept under a dry inert gas such as nitrogen or argon until use. It is ready for introduction into the polymerization reactor where complete activation is then performed.

When an additional activating compound is introduced into the polymerization reactor to complete activation of the precursor, it is metered into the reactor as a dilute solution in a hydrocarbon solvent such as isopentane. These dilute solutions contain about 5 to about 30% by volume of the activating compound.

The activator compound is introduced into the polymerization reactor in an amount such that the Al / Ti ratio in the reactor is maintained at from 10 to 400: 1, preferably from 15 to 60: 1. Examples 1 to 6

In each of these examples, ethylene is copolymerized with 1-butene.

Examples 1 to 3 employ a catalyst prepared as described above. The silica impregnated catalyst system used in Examples 1 and 2 contains 14.5 wt% precursor, and the silica impregnated catalyst system used in Example 3 contains 20.0 wt% precursor. The silica used as carrier for the catalyst of Example 2 is treated with triethyl aluminum before use to prepare the supported catalyst.

The catalysts used in Examples 4 to 6 were prepared by methods that do not fall within the scope of the invention and are for comparison purposes. The catalyst of Example 4 was prepared by physically mixing 7.5% by weight nenapuštěného precursor prepared according to example la to 92.5% by weight of polyethylene powder ^1. High density low density ethylene homopolymer (below 940 kg / m < ^{3 &gt};) having a mean particle size of about 50-150 [mu] m is used as the polyethylene powder. The catalyst used in Examples 5 and G is prepared by physically mixing 20 ¹ % by weight of impregnated precursor. prepared according to Example 1a, and 80 percent by weight of a silica having a specific surface area of 300 m ² / g and an average particle size of 70 µΐΐ. In each of Examples 1 to 6, the precursor is partially activated with triethyl carbon to obtain an alumina system and precursor. with the Al / Ti 5 + 1 molar ratio. The completion of the activation of the precursor in the polymerization reactor is carried out with a 5% (w / w) solution of triethyl aluminum in isopentane to obtain a fully activated catalyst with an Al / Ti molar ratio of 25 to 30.

Each reaction is carried out in a fluidized bed reaction system for 1 hour from equilibrium at 85 ° C and 2.06 MPa at a rate of about three to six times the Gmf and a spatial velocity of 71.3 to 102.2 kg / m ² / h. The reaction system described above is shown. Its lower part is 3.03 m high and its inner diameter is 0.343 m. The upper part is 4.88 m high and its inner diameter is 0.597 m.

Table 1 shows the molar ratio of 1-butsn-ethylene, the molar ratio H 2 / ethylene and the yield per unit of time and space [kg / h / m ³ bed space] in each example, different properties of the polymers produced and different properties of the film samples. made of these polymers.

Compared to granular copolymers produced according to U.S. Patent Application No. 852,235, filed Mar. 31, 1978 (FJ Karol et al.): Preparation of ethylene copolymers in a fluidized bed reactor) the copolymers of the invention have a raw powder state at a given density and index. melt flow, smaller mean particle size, narrower molecular weight distribution, easier to fluidize, higher bulk density, and easier to transport pneumatically. The films made from the copolymers produced by the methods of the invention have substantially better properties than the films made from the copolymers produced by the cited patent application.

Table I

Example 2 1 3 4 5 6 Working conditions molar ratio C4 / C2 0.448 0.472 0.402 0.462 0.423 0.401 H2 / C2 molar ratio 0.193 0.215 0.535 0.204 0.207 0.394 yield per unit of time and space [kg / h / m ³ bed space] 87.5 102.2 84.3 71.3 85.9 Polymer properties Melt flow index [g / 10 min]. 1,8 2.2 17.8 2.3 1.3 15.7 Ratio of melt flow rates 25.3 25.1 23.7 25.5 25.3 25.0 Density [kg / m ³ ] 923.8 920.8 927.8 924 923 928 Ti [ppm] 5—6 5—6 7—9 2—3 2—3 1 % ash 0,042 0,049 0,059 - 0,034 0,034 Film properties Gloss (%) 159 141 Turbidity (%) 9.7 13.6 - - - - Hexane Extractable Content (%) 0.17 0.41 Movie rating • + 30 + 2.5 - + 40 —60 - Properties of granulate density [kg / m ³ ] 339 313 404 235 259 271 At _{m £} [m / s] 0.14 0.19 0.08 0.40 0.22 - U, n x [m / s] 0.26 0.37 0.21 0.64 0.34 Sieve analysis [° / o weight] Sieve size 8 mesh 1.4 1,8 0.0 · 7.7 17.4 1.3 12 mesh 4.4 8.7 0.4 28.5 14.4 2.5 20 mesh 27.7 38.7 13.4 42.9 28.4 11.4 40 mesh 40.2 37.1 47.9 15.9 19.0 41.9 60 mesh 16.7 11.0 25.3 4.0 9.1 25.4 100 'mesh 7.0 '2,2 9.4 0.6 8.1 14.7 bowl 2.6 0.6 3.6 0.2 3.4 2.8 Medium part size [mm] 0,822 0.95 0.559 1,488 1,377 0.584

Example 7 to 10

In each of these examples, ethylene is copolymerized with 1-butene.

In these examples, the catalyst precursor impregnated with silica is prepared as described above. The catalyst system impregnated with silica contains 20.0% by weight of precursor. The silica support used to prepare the catalysts in these examples is treated with triethyl aluminum before impregnation. In each of these examples, the precursor is partially activated with the aluminum compound listed in Table II as described above to obtain an impregnated precursor with an Al / Ti molar ratio as shown in Table II.

Completion of the precursor activation in the polymerization reactor is accomplished with a 5% (w / w) solution of triethylaluminium in isopentane to provide a fully activated catalyst with an Al / Ti molar ratio of 25 to 25 in the reactor.

30.

The polymerization reactions were carried out in the same manner as in Examples 1 to 6.

Table II shows the Al / Ti molar ratio values in the preparation of the precursor, 1-butene / ethylene, H2 / ethylene molar ratio and space / time yield [kg / h / m ³ ], in each example, and various properties obtained polymers.

213014

2δ

Table II

7 8 9 10

Example

Activation of Precursor Activating Compound ¹ Al / Ti molar ratio TEAL 4,5 TIBAL 6.7 TIBAL 4,5 TNHEXAL TNOCTAL 6.6 7.5 Working conditions C4 / C2 molar ratio 0.448 0.375 0.369 0.375 0.368 H2 / C2 molar ratio Yield based on space and time 0.193 0.266 0.247 0.266 0.249 [kg / h / m ³ bed space] 87.5 94.0 81.1 85.9 126.5 Polymer properties Melt flow index [g / 10 min] 1,8 2.8 1.1 2.9 2.2 Ratio of melt flow rates 25.3 29.9 25.5 28.4 26.4 Density [kg / m ³ ] 923.8 920 928 921 923 Ti [ppm] 5—6 3—5 2—4 3—5 2—4 % ash 0,042 0,037 0.030 0,036 0,023 Properties of granulate density [kg / m ³ ] 339 415 319 425 344 mean particle size [mm] ¹ TEAL = triethylaluminum TIBAL = tri-isobutylaluminum TNHEXAL = tri-n-hexylaluminum TNOCTAL - tri-n-octylaluminium 0,823 1,240 1,252 1,176 1,367

The examples, the parameters of which are given in Table II, show that copolymers of high bulk density, low catalytic residue content and good properties can be prepared using the catalysts of the invention prepared using two different activating compounds.

Claims (4)

Subject A catalytic system consisting of a precursor of the general formula M & nTMORjnXpfEDJq where represents ED electron donor compound, m number from 0.5 to 56 including limit values, n number 0.1 or 2, p number from 2 to 116 including limit values, q number from 2 to 85 including limit values, R a C 1 -C 14 aliphatic or aromatic hydrocarbon radical or a radical of formula COR ‘, where R‘ represents a C 1 -C 14 aliphatic or aromatic hydrocarbon radical, and X chlorine, bromine or iodine or a mixture thereof, which is impregnated into a porous support and is either not activated or partially activated by not more than 10 moles of activating compound per mol of titanium contained in the precursor, or fully activated> 10 to 400 moles activating agent INVENTION the compound per mole of titanium contained in the precursor, wherein the activating compound is a compound of the general formula Al (R ') _c X _d ' H _e where X ‘represents chlorine or a group of the formula OR‘ and each of the symbols R "and R" ', which are the same or different, represent a C 1 -C 10 saturated hydrocarbon radical, d is 0 to 1.5 e is 1 or 0, the sum of c + d + e being 3, and the electron donor compound is a liquid organic compound in which the precursor is soluble, selected from the group consisting of alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones. 2. A process for the preparation of a catalytic system according to claim 1, characterized in that: While preparing a precursor of the formula Mg _RIL Ti (OR) "X _p [ED] _q wherein represents ED electron donor compound, m number from 0.5 to 56 including limit values, n number 0, 1 or 2, p number from 2 to 116 including limit values, q number from 2 to 85 including limit values, R 1 to C 1 is an aliphatic or aromatic hydrocarbon radical or a radical of formula COR ‘, where R‘ represents a C 1 to C 1 aliphatic or aromatic hydrocarbon radical and X represents chlorine, bromine or iodine, or a mixture thereof, by dissolving at least one magnesium compound and at least one titanium compound in at least one electron donor compound to form a solution of the precursor in the electron donor compound, and then isolating the precursor from said solution, is used a compound of the general formula MgX ₂ where X is as defined above as the titanium compound used is a compound of the general formula Ti (OR) _and X 'where a is the number 0, 1 or 2 and b is the number 1 to 4 inclusive, where the sum of a + b is 3 or 4 and R and X are as defined above, and the electron donor compound is a liquid organic compound in which the magnesium compound and the titanium compound are soluble selected from the group consisting of alkyl esters of aliphatic and aromatic carboxylic acids, aliphatic ethers, cyclic ethers and aliphatic ketones; wherein the magnesium compound, the titanium compound and the electron donor compound are used in amounts to suit the meaning of the symbols m, n, paq, then B) a porous support is impregnated with a precursor either before or after isolation from the electron donor solution, then optionally C) the precursor partially activates not more than 10 moles or completely activates> 10 to g 400 moles of activating compound per mole of titanium contained in the precursor, the activating compound being a compound of the formula Al {R "} _c X ₍ 1'H _e where X ‘represents chlorine or a group of the formula OR" ‘and each symbol R "and R" ', which are the same or different, represent a C 1 to C 11 saturated hydrocarbon radical, d is 0 to 1.5 e is 1 or 0, the sum of c + d + e being 3, wherein the activation is performed after isolating the precursor impregnated in the porous carrier from the solution of the precursor in the electron donor compound. 3. Process according to claim 2, characterized in that the partially activated precursor is fully activated in the polymerization reactor> 10 to:. 400 moles of activating compound per mole of titanium compound contained in the precursor. 4. The process of claim 2, wherein the partially activated precursor is fully activated > 10 to 400 moles of activating compound per mole of titanium in the precursor, wherein the complete activation is performed to form a solid, dry catalyst system prior to dosing the system. and to avoid having to heat the catalyst system to a temperature above 50 ° C.