CS215015B2 - Method of catalytic production of ethylene copolymere - Google Patents

Abstract

The present invention relates to a process for the catalytic production ethylene copolymer using a catalyst containing titanium in productivity > 50,000 kg of polymer per kg of titanium in reactor at a pressure below 6.87 MPa in the gas phase, wherein the polymer is formed in granular form and has a density of 910 to 940 kg / m 3, inclusive limit values, and the flow rate ratio melt 22 to 32, including limit values. The process is characterized in that ethyl copolymerizes together with at least one C3 to Ce α-olefin at 30 to 105 ° C the monomer feed is contacted in the presence 0 to 2.0 moles of hydrogen per mole of ethylene in the reaction zone for gas phase reactions with catalyst system particles containing a precursor which is the reaction product magnesium halide, certain compounds titanium and electron donor compounds and which it is impregnated in a porous carrier. Precursor is activated by an organoaluminum compound. Polymerization is preferably carried out in a fluidized bed loži. The copolymers obtained are suitable for production foil. ;

Description

The invention relates to a process for the catalytic production of an ethylene copolymer using a catalyst containing titanium at a productivity of> 50,000 kg of polymer per kg of titanium in a reactor at a pressure of less than 6.87 MPa in the gas phase. kg / m ³ , including limit values, and a melt flow rate ratio of 22 to 32, including limit values.

The method is characterized in that the ethyl copolymer is co-polymerized with at least one C 3 -C 6 α-olefin at a temperature of 30 to 105 ° C by contacting the monomer feed in the presence of 0 to 2.0 moles of hydrogen per mole of ethylene in the reaction a gas-phase reaction zone with particles of a catalyst system containing a precursor which is the reaction product of a magnesium halide, a titanium compound and an electron donor compound, and which is impregnated in a porous support. The precursor is activated by an organoaluminum compound. The polymerization is preferably carried out in a fluidized bed. The copolymers obtained are suitable for the production of films. ;

The invention relates to a process for the catalytic production of an ethylene copolymer using highly active complex catalysts containing magnesium and titanium in a gas phase process to produce ethylene copolymers having a density of 9.1.0 · kg / m ³ inclusive to 940 kg / m ³ inclusive with melt flow rates (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 U.S. Patent No. 4,011,382 and Belgian Patent No. 839,380, it has been found that low pressure polyethylene can be industrially produced under a pressure of less than 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 of from 6 to 20 (including limit values), as such are well applicable in numerous applications in the field of wire and cable insulation and hose production, but not very suitable 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.

For catalysts to be useful in an industrial gas phase process such as the fluidized bed process of U.S. Patent Nos. 3,709,853, 4,003 7,12 and 4,011,382, Canadian Patent 991,7S8 and Belgian Patent No. 839,380, they must have high activity, ie, it must have a productivity of at least 50,000 and preferably at least 100,000 kg of polymer per kg of parent metal which forms the catalyst, or higher. This is because, in such gas-phase processes, no processes are generally used 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 production of the resins, in the processing of the resins and / or in the application of the finished products to the end customer. Where highly active catalysts are successfully used in such fluidized bed processes, the heavy metal content of the resin is of the order of 20 · ppm parent metal or less at a productivity of at least 50,000 or greater, 10 ppm or less at a productivity of at least 100,000 · or higher and 3 ppm or lower at a productivity of 300,000 or higher. 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 (pulsation corrosion and other corrosion of the metal surfaces of the molding machines. A chlorine content of 200 ppm or higher is unbearable for industrial production.

U.S. Pat. No. 3,989,881 discloses the use of a highly active catalyst for a slurry process for producing ethylene polymers having a relatively 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 disclosed in U.S. Patent No. 3,989,881 to produce polyethylene with a narrow molecular weight distribution by polymerizing ethylene alone or in conjunction with gas-propylene propylene using equipment 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. In order to avoid the use of solvents used in the catalyst systems of the slurry type described in U.S. Patent No. 3,989,881, titanium and magnesium containing components were dried. However, the dried substance was in the nature of a viscous, resinous pyrophoric substance which could not be fed well into the reactor because it was not freely movable. Even when this mobility agent was mixed with silica and fed to the reactor in this form, industrially acceptable results were not achieved. Catalyst productivity was low, or the catalyst was pyrophoric and difficult to handle, or 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 granulated polymer is to be processed into pellets prior to shipping, processing such a large amount of low density substance in a pelletizer requires a considerably longer processing time 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 MX2 (where M may be magnesium) with a 21S01S compound of formula M‘Y (where M ‘may be titanium and Y a halogen or an organic moiety) in an electron donor compound. These complexes are then isolated by either crystallization, solvent evaporation, or precipitation.

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

However, U.S. Patent No. 4,124,532 does not disclose any special technique or methods for preparing the catalyst 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, the gas phase examples do not disclose a practical copolymerization process suitable for the production of special low density copolymers having the preferred morphology of the invention described in these teachings.

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 fluidized bed gas phase 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 100 ppm Ti and more than about 300 ppm Cl, are obtained, as exemplified in this patent. In addition, as exemplified in U.S. Patent 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 large equipment for the production, storage and transport of the catalyst.

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

No. 892,325, filed Mar. 31, 1978 (FJ Karol et al., Title: Preparation of Fluidized Bed Ethylene Copolymers) discloses that ethylene copolymers having a density of 910-960 kg / m ³ , with a velocity ratio A melt flow rate (defined below) of from 22 to 32, including limit values, and with low catalyst residue content can be produced in granular form at relatively high productivity by polymerizing the monomer or monomers by a gas phase process using a specific highly active magnesium-containing complex catalyst. and a 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 molding resins. 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 materials into the molding and extruder requires a longer dosing time than is the case of dispensing the same weight of the pelletized substance, since a larger volume of the granular material 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 or less.

It has now been unexpectedly found that ethylene copolymers with a wide density range of 910i to 940 kg / m ³ and a melt flow rate ratio of 22 to 32, including limit values having relatively low catalyst residue content and relatively high bulk density, can provide films of good clarity, prepared at high productivity, suitable for industrial production, by gas-phase copolymerization of ethylene with one or more C 3 -C 6 -olefins in the presence of a highly active catalyst comprising a magnesium-titanium complex described below prepared under specific activation conditions by means of organoaluminum compounds, impregnated in a porous inert carrier.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a process for the production of ethylene copolymers having a density of about 910 to about 940 kg / m ³ , with a melt flow rate ratio of about 22 to 32 including limit values, relatively low catalyst residues. / m ³ , which would provide films with good properties, by a low pressure gas phase process with relatively high productivity.

It is a further object of the present invention to provide granular ethylene copolymers whose particles have a rounded shape and are more readily fluidized in a fluidized bed and which contain relatively small amounts of fines.

The process according to the invention provides new ones

215013 ethylene copolymers suitable for numerous applications.

The attached figure shows a fluidized bed reaction system for a gas phase process in which the catalyst system of the invention can be used.

By the process according to the invention, copolymers can be prepared containing, as the main molar part, ethylene (with 50% and as minor molar part (g: 10% / o) one or more C 3 -C 6 -olefins which should not contain any branching on any of their atoms If one of the C 5 -C 6 olefins is used, copolymers are obtained, if more C 3 -C 6 alpha olefins are used, ter- or tetrapolymers are obtained and the like. olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1hepten and 1-octene. Preferred 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 limit values) corresponds to an Mw / Mn value of about 2.7 to 4.1 and an MFR of 25 to 30 (including limit values) corresponds to an 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 copolymers at a given melt index can be controlled primarily by the amount of Cs to Ce comonomer to be copolymerized with ethylene. In the absence of comonomer, 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 copolymers. 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.

Increasing molar amounts of comonomers in the range C3> Cd> C5> C6> are needed to achieve the same results, ie the same density at a certain melt index.

> C7> C8.

The melt index of the polymers is a reflection of its molecular weight. The relatively high molecular weight polymers have a relatively low melt index. Ultra high molecular weight ethylene polymers have a higher melt flow index (HLMI of about 0.0 and very high molecular weight polymers of about 0.0 to about 1.0 g / 10 min. Such high molecular weight polymers are difficult to mold in conventional injection molding machines. The copolymers produced by the process of the invention, on the other hand, are easily formed in such a device, having a melt index under normal load (MI) ranging from ≥ 0.0 to 100, preferably ranging from approximately 0.5 The melt index of the polymers produced by the process of the present invention is dependent on the combination of the polymerization reaction temperature, the copolymer density, and the hydrogen / monomer ratio in the reaction system. with increasing polymerization temperature and / or decreasing polymer density and / or increasing hydrogen / monomer ratio. Other chain transfer agents such as dialkyl zinc compounds can also be used to further increase the melt index of the copolymers.

The copolymers produced by the process according to the invention contain 11 and usually 0,1 0.1 to 0.5

0.3 C-C double bonds per 1000 carbon atoms and have a content of n-hexane extractables (at 50 ° C) of less than about 3% and preferably less than about 2% by weight.

The copolymers produced by the process of the invention contain as catalyst residues of the order of 0 to 20 ppm of Ti inclusive at a productivity of 50,000 * or higher, from 0 to 10 ppm inclusive of Ti at a productivity of 100,000 or higher and 0 to 3 ppm inclusive at a productivity of 300,000 · Or higher. With respect to the Cl, Br or I residues, the content of these elements in the copolymers depends on their content in the catalyst precursor. From the ratio of the amount of titanium κ of chlorine, bromine or iodine in the original precursor, the content of chlorine, bromine or iodine residues can be calculated based on the known productivity value relative to the titanium residue itself.

For many copolymers produced using only chlorine-containing catalyst system components (Cl / Tl = 7), chlorine residues can be calculated in the range of 0 to 140 ppm inclusive at 50/000 productivity or higher, from 0 to 70 ppm inclusive 100,000 or greater and from 0 to 20 ppm at a productivity of 300,000 or greater. In the process of the invention, the copolymers are readily produced at productivity rates of up to about 500,000.

The copolymers produced by the process of the invention are granular materials having a mean particle size of the order of about 0.127 to about 1.78 mm and preferably about 0.5 to about 1 millimeter. The particle size is important for the easy fluidization of the polymer particles in the fluidized bed reactor as described below. The copolymers produced by the process of the invention have a bulk density of from about 308 to about 503 kg / m ³ .

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

For the production of films, it is preferable to use those copolymers according to the invention having a density of about 9.12 to 940, preferably 9.16 to 928 kg / m ³ , including limit values, a molecular weight distribution of 2.7 mW / Mn 3.6, preferably 2, 8 M Mw / Mn 3,1 3.1, and a standard melt index (MFI) of 0.5 MF MFI 5 5.0, preferably about 0.7 MF MFI 4,0 4.0. The films have a thickness of from 0 to 0.25 mm, preferably up to 0.12 mm and most preferably up to 0.025 mm.

The copolymers produced according to the invention suitable for injection molding on flexible articles, such as household articles, preferably have a density of from 920 to S40, preferably from 925 to 930 kg / m ³ , including limit values, molecular weight distribution range of 2.7áMw / Mn3.6, preferably 2.8 µMw / Mn3.1, and a 2 µMf3g value of 100, preferably about 8 and an MFI of 80.

The compounds used to prepare the highly active catalyst to be used according to the invention include at least one titanium compound, at least one magnesium compound, at least one electron donor compound, at least one activating compound, and at least one porous inert substance as a carrier.

The titanium compound has a structure corresponding to the general formula

Ti (OR) _and X _b wherein represents

R 1 to C 11 is an aliphatic or aromatic hydrocarbon radical or a radical of formula

COR * where

Ø * represents a C 1 to C 14 aliphatic or aromatic hydrocarbon radical,

X is chlorine, bromine, iodine, or a mixture thereof, and a number of 0, 1 or 2, b of a number from 1 to 4 inclusive, wherein the sum of a + b is 3 feet 4.

The titanium compound can be used singly or in mixtures and includes compounds of the formulas

TiCb,

TiCii,

Ti (OCH ₃ ) Cl ₃ ,

TifOCeHsjCb,

Ti (OCOCH ₃ ) Cl ₃ and TifOCOC 6 H ₂ Cl ₂ .

The magnesium compound has a structure corresponding to the general formula

MgX ₂ where

X represents chlorine, bromine, iodine or a mixture thereof.

These magnesium compounds can be used singly or in combination and include compounds of the formulas MgCl 2, MgBra and Mgh. 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 26 ° 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 4 saturated aliphatic carboxylic acids, C ₂ to C 5, and preferably C 5 to C 4 aliphatic ethers, C 5 to C 4 cyclic ethers, and preferably C 5 cyclic mono- or diethers, C 5 to C 6 preferably C .; to Ci aliphatic ketones. Most preferred of these electron donor compounds are methyl formate, ethyl acetate, butyl acetate, ethyl ether, hexyl ether, tetrahydrofuran, doian, acetone and methyl isobutyl ketone.

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

Per mole of titanium it is used about 2 to 85 moles and preferably about 3 to 10 moles of the electron donor compound.

The activating compound has a structure corresponding to the general formula

Al (R 'j _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 1-4 saturated hydrocarbon radical; . d is 0 to 1.5 e is 1 or 0, the sum of c + d + e being 3.

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

A1 (C2H5) 3

A1 (CzH5) 2C1

Al (i-C4Hg) 3,

Al2 (C2H5) 3Cl3,

Al (1-C 1 H 9) 2H,

A1 (CsHi3) 3,

A1 (CsH17) 3

A1 (C2H5) 2H and

Al (Cl 2 H 5) 2 (OC, ₂ H ₅ ).

About 10 to 400, and preferably about 10 to 100 moles of activating compound per mole of titanium compound are used to activate 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 an average particle size of about 10 to 250 µm, 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 7 nm and preferably at least 10 nm and larger. The carrier should be dry, ie not contain absorbed water. The carrier is dried by heating to a temperature of at least 600 degrees Celsius. 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 catalyst used in the process of the invention is prepared by first preparing a precursor from a titanium compound, a magnesium compound and an electron donor compound as follows, then impregnating the support with the precursor, and then treating the precursor impregnated with the activating compound in one or more degrees as described below.

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 to 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 ftm and a bulk density of about 202 to about 535 kg / m ³ .

The precursor thus prepared has a composition corresponding to the general formula

Mg _m Tit (OR) _n X _p [ED] _q where represents

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

R is a C 1 to C 11 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 is chlorine, bromine or iodine or a mixture thereof.

The elemental titanium (Ti) index is the Arab number one.

The carrier is then impregnated with a carrier in a weight ratio of about 0.033 to 1 and preferably 0.1 to 1. 0.33 parts precursor per part 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 requiring the catalyst system to be heated above 50 ° C before being fed to the polymerization reactor.

According to a second preferred method, the precursor is partially activated by the mi215015 mo polymerization reactor in 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 20-80 ° C, preferably ^50! to 70 ° C. The resulting product has the character of a free-flowing particulate material and can be readily introduced into the polymerization reactor. The partially activated impregnated precursor may 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 can be injected into the reactor as a solution in a hydrocarbon solvent such as isopentane, hexane or mineral oil. This solution typically contains about 2 to 30% by weight of the activating compound. The additional activating compound is added to the reactor in an amount such that a total activated Al / Ti molar ratio of from 10 to 400, and preferably about 15 to 60, is achieved in the reactor together with the amounts of activating compound and titanium compound listed as partially activated impregnated precursor. the activator 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, individual comonomer moles are continuously fed into the reactor during polymerization. % of the partially-or fully-activated precursor copolymers impregnated in the carrier, optionally while providing separate doses of the additional activating compound needed to complete activation of the partially-activated precursor, thereby 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, under pressure and temperature, sufficient to initiate polymerization.

In order to achieve the desired density range of the copolymers, it is necessary to copolymerize with ethylene sufficient comonomers with a carbon chain of 3 or more carbon atoms to have a content of C3 to Ca comonomers in the copolymers of 1.0 to 15 moles. %. The amount of comonomer required to achieve this result depends on the particular comonomer 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 comonomer needed in the copolymers to achieve these properties and the relative molar concentration of comonomer relative to ethylene in the recycled monomer gas stream under reaction equilibrium conditions in the reactor.

mol. % needed in the gaseous stream propylene 1-butene 1-pentene 1-hexene 1-ok

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

The fluidized bed reaction system that can be used in the process of the invention is illustrated in FIG. 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 higher than the minimum flow rate required for fluidization.

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 the formation of "hot spots" and that trap and distribute the powdered catalyst in the reaction zone. Upon commencement of operation, the polymer zone is usually introduced into the reaction zone as the basis before the gas stream is started. These particles may be identical to the resulting polymer 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 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 composition of the gas to be recycled and accordingly adjusts the make-up gas composition in order to maintain the composition of the gas mixture in a substantially steady state in the reaction zone.

In order to ensure complete fluidization, the recycle gas and, optionally, part of the make-up gas is fed to the reactor via an inlet 18 below 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 be passed through a filter 24 which is adapted to separate small particles therein at high flow rates and thereby 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 adapts the temperature of the recycle gas above the bed to the bed temperature, 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 a fluidized bed through a distributor plate 20. The compressor 25 may also be located downstream of the heat exchanger 26.

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 can be active, they must be prevented from settling, since if any quiet mass were 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 diffuse 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 screen, slotted plate, perforated plate, plate plate (analogous to the distillation column trays) and the like. All plate portions may be stationary or of a movable type such as The plate described in U.S. Pat. No. 3,298,792. Whatever the plate design, the plate must disperse recycle gas between the particles at the bottom of the bed and keep the particles of the bed fluidized. 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 of the invention. 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 to C 14 'aliphatic or aromatic hydrocarbon radicals.

This further increases the melt index values of the produced copolymers. Into the gaseous stream introduced into the reactor

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) may be added to the reactor, preferably the zinc compound may be introduced into the reactor in the form of a dilute solution. 2% to 10% by weight) in a hydrocarbon solvent or in absorbed form in a solid diluent, such as silica, in an amount of about 10 to 50% by weight, which are typically pyrophoric. from a dispenser adjacent to the dispensing 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 105 ° 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 producing products with a density of about> 920 to 940 ^: kg / m ³ .

The fluidized bed reactor is operated at a pressure of up to about 6.87 MPa, preferably at a pressure of about 1.0-3.3 to 2.40 MPa, and when operating at higher pressures in this range, heat transfer is facilitated since the pressure increase results in an increase in the unit volume heat capacity of the gas.

The 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 located 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 manifold plate could result in polymerization being initiated at this point, which could eventually lead to clogging of the manifold plate. On the contrary, injecting the catalyst into the fluidized bed helps to distribute the catalyst in the bed and avoids the formation of sites with high catalyst concentrations which could lead to hot spots.

For introducing a partially or fully reduced precursor and any non-gaseous activating compound or transfer agent into the bed, an inert gas such as a sip or argon is used.

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

Since any change in catalyst injection rate results in a change in reaction heat evolution rate, the temperature of the recycle gas entering the reactor is adjusted up or down to accommodate variations in heat evolution rate. This ensures a substantially constant temperature in the bed. Both the fluidized bed and the recycle gas cooling system must, of course, be equipped with appropriate devices for detecting temperature changes in the bed and the cooling system so that the operator can appropriately adjust the recycle gas temperature.

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 measurement of the increase in gas temperature along the reactor (i.e., the temperature difference between the temperature of the inlet gas and the temperature of the outgoing gas) determines the rate of polymer particle formation at a constant gas velocity.

The polymer product particles are preferably collected continuously through line 34 or near the distributor plate 20. The particles are collected in the form of a suspension with a portion of the gaseous stream that is vented prior to particle deposition to avoid further polymerization and caking before the particles reach the zone. where they gather. 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 a gas / product mixture into the 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 high performance supported catalyst system used in the present invention provides a fluidized bed product with an average 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 μηα), i.e. less than 4% by weight.

The feed monomer gaseous stream, optionally with inert gaseous diluents, is fed to the reactor at a space and time yield of about 32.4 to about 162.2 kg / hr / m ³ bed volume.

The term "crude resin or po15515 lymer" 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 of the invention 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 measurement is performed at 190 ° C, reported in g per 10 minutes.

Flow rate (melt flow index at higher load) (HLMI)

ASTM-D-1238-Condition F measurements are made using ten times the load of melt index measurements

_FAST speed ratio i _{os t} = Flow Flow --- - Flow Index -taveniny

Productivity

The resin product sample is ashed and is determined by weight of ash as 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.

Bulk density

The resin is poured into a 100 ml graduated cylinder through a 9.5 mm stem funnel up to a 10 ml nozzle. 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 ΙΟ ⁶ , 10 ⁴ , 103, 10 ² , 6 nm. Perchlorethylene at 117 ° C is used as solvent. Detection is performed by infrared radiation at 3.45 µm. Evaluation foil

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

Substances extractable by n-hexane (FDA-Test used for polyethylene films intended to come into contact with food). A film specimen having a thickness of 38.1 μπι and an area 1290 cm ² is cut into strips 2.54 cm by 15.24 cm 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 milligram. The amount of extract calculated on the original sample weight is then reported as the mass fraction of the n-hexane extractables.

Unsaturated

The measurement is 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 µm for transvinylidene unsaturation at

I. 1,0 / grains for terminal vinyl unsaturation and 11,25 μΐη for vinylidene unsaturation in 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 electron donor 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 which has a particle size equal to the silica particles used. The absorbed precursor has a composition corresponding to the formula

TlMg _M Cl ₁₀ (THF) _{6 (7}

Example 1 a d I b

Preparation of the impregnated precursor from a preformed precursor

In a 12 L flask equipped with a mechanical stirrer, 140 g of the precursor are dissolved in

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 stream of nitrogen at a temperature of not more than 60 ° C for about 3-5 hours. A dry, free-flowing powder is obtained having a particle size equal to that of the silica particles.

They did

Activation procedure

The desired 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 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 correspond to the size and shape of the silica particles. The product is not pyrophoric if the aluminum alkyl content is not more than 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 6 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 a carrier for the catalyst of Example 2 is treated with triethyl aluminum before being used to prepare the supported catalyst.

The catalysts used in Examples 4 to 6 were prepared in such a way that their use does not fall within the scope of the invention and serves for comparison. The catalyst of Example 4 was prepared by physically mixing 7.5% by weight of the impregnated precursor prepared according to Example Ia with 92.5% by weight of polyethylene powder. The polyethylene powder used is a high-pressure, low-density ethylene co-polymer of less than 940 kg / m ³ having a mean particle size of from about 50 to 150 µm. The catalyst used in Examples 5 and 6 was prepared by physically mixing 20% by weight of the impregnated precursor prepared according to Example Ia and 80% by weight of silica having a specific surface area of 300 m ² / g and an average particle size of 70%. In each of Examples 1 to 6, the precursor is partially activated with triethyl aluminum to obtain an alumina system and a precursor with an Al / Ti molar ratio of 5 + 1. Completion of the precursor activation 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 in the reactor.

Each of the reactions is carried out in a fluidized bed reaction system for 1 hour after equilibration at 85 ° C and 2.00 MPa at a gas velocity of about three to six times Gmf and a space-time yield of 71.3 up to 10,2.2 kg / m ² / h. The reaction system described above is shown. Its lower part is 3.05 m high and its inner diameter is 0.343 m. The upper part is 4.83 m high and its inner diameter is 0.57 meters.

Table 1 lists the 1-butene-ethylene molar ratio, the H2 / ethylene molar ratio, and the yield per unit time and prostoto ™ yield (kg / h / m ³ bed space) in each example, the different properties of the polymers produced, and made of these polymers.

Compared to granular copolymers produced according to U.S. Patent Application No. 892,235 filed March 31, 1978 (F.J.

Karol et al., Preparation of ethylene copolymers in a fluidized bed reactor) the copolymers of the present invention have a lower mean particle size, a narrower molecular weight distribution, easier fluidization, a higher bulk density, and a high bulk density. are pneumatically conveyed. Films made from copolymers produced by the process of the invention have substantially better properties than films made from copolymers produced according to 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 0.4011 H2 / C2 molar ratio 0.193 0.215 0.535 0.204 0.207 0.394 yield based on 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 (O / o) 159 141 - - _ - Turbidity (θ / ο) 9.7 13.6 - .— - - Content of extractable substances hexane (%) 0.17 0.41 - - - —- Movie rating + 30 + 25 _ + 40 —60 - Properties of granulate density (kg / m ³ ) 339 313 404 235 259 271 U _mf (m / sec) 0.14 • 0.19 0.08 0.40 0.20 -. U, _11X (m / sec) 0.26 0.37 0.21 0.64 0.34 - Sieve analysis (% by 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 Mean particle size (mm) 0,822 0.95 0.559 1,488 1,377 0.584 Examples 7 to 10 se earned impregnated precursor with molar

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

In these examples, a 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 impregnating the precursor. In each of these examples, the precursor is partially activated by the aluminum compound listed in Table II as described above to give the Al / Ti ratio shown in Table II.

Completion of the precursor activation in the polymerization reactor is accomplished with a 5% (w / w) solution of triethylaluminum in isopentane to provide a fully activated catalyst with an Al / Ti molar ratio of 25 to 30 in the reactor.

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

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

Table II

Example 2 7 8 9 10 Activation of precursor Activating compound ¹ TEAL TIBAL TIBAL TNHEXAL TNOCTAL Al / Ti molar ratio 4,5 6.7 4,5 6.6 7.5 Working conditions C4 / C2 molar ratio 0.448 0.375 0.369 0.375 0.368 H2 / C2 molar ratio 0.193 0.2166 0.247 0.266 0.249 Yield based on space and time [kg / h / rn 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] 0,823 11,240 1,252 1,176 1,367

^X TEAL = triethylaluminum Examples whose parameters are given

TIBAL - tri-isobutylaluminium in Table II, show that copolymers with high THNHEXAL = tri-n-hexylaluminium bulk density, low content

TNOCTAL = tri-n-octylaluminum catalyst residues and good properties can be prepared using the catalysts of the invention which have been prepared using two different activating compounds.

Claims (3)

SUBJECT Process for the catalytic production of an ethylene copolymer using a catalyst containing titanium at a productivity of 50,000 kg polymer per kg of titanium in a reactor at a pressure below 6.87 mPa in a gas phase, the polymer being formed in granular form and having a density of 910-940 kg / m ³ , including limit values, and a melt flow rate ratio of 22 to 32, including limit values, characterized in that the ethylene is copolymerized with at least one C 5 to C 8 alpha-olefin at a temperature of 30 to 105 ° C by monomer the batch contacts in the presence of 0 to 2.0 moles of hydrogen per mole of ethylene in the reaction zone and in the gas phase with particles of a catalyst system consisting of a precursor of the general formula Mg _m Ti (OR) _n X _p [ED] _q 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 1 to C w is an aliphatic or aromatic hydrocarbon radical or a radical of formula COR ‘, where R‘ represents a C 1 to C 14 aliphatic or aromatic hydrocarbon radical, X chlorine, bromine or iodine, or a mixture thereof, which is impregnated into a porous support and is initially partially activated outside the reactor by not more than 10 moles of activating compound per mole of titanium contained in the precursor and then fully activated either outside the reactor> 10 to 400 moles of activating compound mole of titanium in the precursor, wherein complete activation is effected to form a solid dry catalyst system prior to feeding the system to the polymerization reactor, without the need to heat it to above 50 ° C during those activation stages that are carried out with a quantity of activation. of the compound above 10 moles, or fully activated in the reactor> 10 to 400 moles of activating compound per mole of titanium contained in the precursor, the activating compound being 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 symbol R "and R" ', which are the same or different, represent a C 1 -C 10 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. 2. A process according to claim 1, wherein the process is carried out in a fluidized bed. 3. The process of claim 1 wherein the precursor is partially activated with no more than 10 moles of activating compound outside the reactor and then fully activated within the reactor with an amount of activating compound such that an Al / Ti molar ratio is achieved in the reactor.