RU2446176C2 - Catalytst components for polymerisation of olefins and catalysts obtained therefrom - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to catalyst components for polymerisation of olefins. Described are catalyst components for polymerisation of olefins which contain Ti, Mg, Al, CI and optionally OR¹ groups, in which R¹ denotes a C1-C20 hydrocarbon group optionally containing heteroatoms, so as to obtain molar ratio OR¹/Ti less than 0.5, where essentially all titanium atoms are in a valence state equal to 4, and porosity (P_F), which is measured using a mercury method and resulting from pores with radius equal to or less than 1 mcm, is at least 0.30 cm³/g, and that molar ratio Cl/Ti is less than 29. Described are methods of obtaining said components, involving a step (a) where a compound MgCl₂·mR¹¹OH tH₂O, in which 0.3 ≤ m ≤ 1.7, t ranges from 0.01 to 0.6 and R¹¹ denotes an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, reacts with a titanium compound of formula Ti(OR¹)_nX_y-n, in which n lies between 0 and 0.5, y is the valence of titanium, X is a halogen and R¹ is as defined above, in the presence of an aluminium compound of formula AlL₃, where L independently denotes OR¹ groups, in which R¹ denotes a C1-C20 hydrocarbon group or a halogen. Described is a method for polymerisation of olefins, which is realised in the presence of a catalyst system containing a product of reaction of the described catalytic components and an alkylaluminium compound.

EFFECT: described catalyst components are characterised by high morphological stability in low molecular weight ethylene polymerisation conditions while maintaining high activity.

15 cl, 4 tbl, 21 ex

Description

The present invention relates to catalytic components for the polymerization of olefins CH ₂ = CHR, where R is a hydrocarbon radical containing 1-12 carbon atoms. In particular, the invention relates to catalytic components suitable for the preparation of ethylene homopolymers and copolymers, and to catalysts prepared therefrom. In addition, the invention also relates to homo- and ethylene copolymers having high molten flow and satisfactory morphological properties, and to ethylene polymers with a wide molecular weight distribution with a spherical shape and satisfactory morphology.

In particular, the present invention relates to a solid catalytic component comprising titanium, magnesium and halogen having a specific combination of physical and chemical characteristics. In addition, the present invention relates to a method for producing ethylene homopolymers and copolymers having a high melt flow ratio (F / P), which is the ratio between the melt index measured with a load of 21.6 kg (melt index F) and the index melt, measured with a load of 5 kg (melt index P), determined at 190 ° C in accordance with ASTM D-1238. The indicated F / P ratio is generally regarded as an indication of the width of the molecular weight distribution (MMP).

MMP is a particularly important characteristic for ethylene (co) polymers in that it affects both the rheological behavior and, therefore, the melt processability and the final mechanical properties. Polyolefins having a wide MMP, especially in combination with relatively high average molecular weights, are preferred in blow molding and high speed extrusion processing, for example, for the manufacture of pipes. In fact, products characterized by a wide MWD have excellent mechanical properties that make them suitable for applications that require high voltage resistance. The processing conditions for these polymers are peculiar, and in fact under these conditions it is impossible to process the product with a narrow MWD, because there may be malfunctions due to rupture of the extrusion stream.

Since it is difficult to obtain affordable catalysts that offer the correct model of molecular weight distribution and average molecular weight, one of the most common methods for producing polymers with a wide MMP is a multi-stage process based on the production of polymer fractions with different molecular weights at each stage, sequentially forming macromolecules with different lengths.

The regulation of the molecular weight obtained at each stage can be carried out in accordance with various methods, for example, by varying the polymerization conditions or the catalyst system at each stage or by applying a molecular weight regulator. Hydrogen control is the preferred method, carried out either in suspension or in the gas phase. This latter type of process is currently highly preferred both because of the high quality of the products obtained and because of the low operating costs associated with it.

For the catalyst involved in such a process, the critical step is one in which a low molecular weight fraction is obtained. In fact, one of the important features that the catalyst should possess is the so-called “reaction to hydrogen”, that is, a measure of the ability to reduce the molecular weight of the polymer obtained in relation to the increase in hydrogen concentrations. A higher hydrogen response means that less hydrogen is required to produce a polymer with a specific molecular weight. In turn, this would also normally affect the higher polymerization activity, because it is possible to relatively lower the amount of hydrogen, which has an overwhelming effect on the catalytic activity.

In addition, due to the polymerization conditions and the characteristics of the polymer obtained at this stage (essentially higher brittleness), the catalyst and polymer system is often fragmented into very small particles, which reduce the bulk density of the polymer and create a large amount of finely divided product, which makes work difficult plant, especially during polymerization in the gas phase. One way to solve this problem will be to perform the step of obtaining a fraction of low molecular weight after the first stage, which produces a fraction of high molecular weight. While this option can help smooth out plant performance, this undoubtedly causes a deterioration in the final properties of the product, which, as it turns out, becomes less homogeneous. Therefore, another important feature of the catalyst would be its suitable morphological resistance under conditions of polymerization in the gas phase with a low molecular weight.

EP-A-601525 discloses catalysts which, in some cases, are capable of imparting a wide MMP to ethylene-based polymers (reported F / E ratios of 120, where F / E means the ratio between the melt index measured with a load of 21.6 kg ( melt index F), and a melt index measured with a load of 2.16 kg (melt index E), determined at 190 ° C. according to ASTM D-1238). Such catalysts are prepared by reaction between the Ti compound and the MgCl ₂ · EtOH adduct, which is first subjected to physical dealcoholization and then chemical dealcoholation carried out with the aluminum alkyl compound. As a result, until a preventive deactivated treatment of Al-alkyl residues is carried out, a significant amount of Ti compound fixed on the final catalyst component has an oxidation state lower than 4. When a preventive deactivated treatment is carried out, Ti fixed on the catalyst is in a smaller amount, which leads to the fact that the specified catalyst has a very high molar ratio of Cl / Ti and more Al residue than titanium. The patent application reports satisfactory performance in terms of morphological resistance (expressed by bulk density) under traditional suspension polymerization conditions, which, however, are not predictable for behavior under low molecular weight polymerization conditions when a large amount of molecular weight regulator (hydrogen) is used. Of course, the applicant carried out polymerization tests under these required conditions and proved that a substantial amount of the catalyst decomposes in the early stages of polymerization, giving rise to polymer finely divided products and / or with an inhomogeneous morphology, thereby achieving a very low final bulk density.

WO 00/78820 discloses catalysts capable of producing broad MMP ethylene polymers characterized by total porosity (mercury method), preferably in the range of 0.38-0.9 cm ³ / g and surface area (BET method), preferably in the range of 30- 70 m ² / g. Pore distribution is also specific; in particular, in all the catalysts described in the examples, at least 45% of the porosity is due to pores with radii of up to 0.1 μm. The catalyst components are obtained by (a) a first reaction between a Ti compound and an MgCl ₂ · EtOH adduct which undergoes physical alcoholcoholization, (b) an intermediate treatment with an aluminum alkyl compound, and (c) a second reaction with a titanium compound. Also in this case, the catalysts contain a significant amount of titanium having a reduced oxidation state, and, in addition, show a rather low amount of residual Al in the final catalyst. Despite satisfactory performance under traditional polymerization conditions, it shows unsatisfactory behavior under the required test conditions used by the applicant. This is also confirmed in the said document by the fact that when polyethylene with a wide MMP with two consecutive stages of polymerization is obtained, a fraction with a low molecular weight is always obtained in the second stage of polymerization.

Therefore, there is still a need for a catalyst having high morphological stability under low molecular weight ethylene polymerization conditions while maintaining high activity characteristics.

Applicant has unexpectedly discovered that catalysts representing the following combination of features are capable of satisfying needs. Accordingly, it is an object of the present invention to provide a catalyst component comprising Ti, Mg, Al, Cl and optionally OR ¹ groups in which R ¹ is C1-C20 hydrocarbon groups optionally containing heteroatoms, up to the amount such as to obtain an OR molar ratio ¹ / Ti lower than 0.5, characterized in that essentially all of the titanium atoms are in a valency state of 4, that the porosity (P _F ) measured by the mercury method and due to pores with a radius equal to or lower than 1 μm is at least m D 0.30 cm ³ / g, and the molar ratio of Cl / Ti is lower than 29.

Preferably, in the catalyst of the present invention, the Cl / Ti molar ratio is lower than 28, more preferably lower than 25, and most preferably in the range 13-23. The molar ratio Mg / Al can range from 1 to 35, preferably from 3 to 30, more preferably from 4 to 20, and most preferably in the range of 4-16. Throughout this application, the wording “substantially all titanium atoms are in a valence state of 4” means that at least 95% of the titanium atoms have a valence state of 4. Preferably, the content of Ti atoms with a valence state lower than 4 is less than than 0.1% and more preferably they are absent (not detected by the method used described in the qualification section). The amount of Ti is typically higher than 1.5%, preferably higher than 3%, and more preferably equal to 3.2% or higher than 3.2%. Most preferably, it ranges from 3.5 to 8% wt. The amount of Al is typically higher than 0.5% by weight, preferably higher than 1%, and more preferably in the range of 1.2-3.5%. Preferably, the amount of Al is lower than the amount of Ti.

The catalyst of the present invention also shows another unusual feature. The amount of total detectable anions in accordance with the methods described in the qualification section on a solid catalyst component is usually not enough to satisfy the total number of positive valencies derived from cations, including, but not limited to, Mg, Ti, and Al, even taking into account the possible presence of OR groups. In other words, it is noted that in the catalyst of the invention a certain amount of anions is often insufficient to satisfy all the valencies of the cations. In accordance with the present invention, the missing amount is defined as “LA factor”, where “LA factor” is the molar equivalent of anionic species lacking to satisfy all molar equivalents of cations present in the solid catalyst component that are not satisfied with the total molar equivalent of anions present in solid catalyst component, with all molar equivalents of anions and cations refer to the molar amount of Ti.

The “LA factor” is first determined by calculating the molar contents of all anions and cations determined by analysis. Then the molar content relative to all anions (including, but not limited to, Cl ^- and ^- OR) and cations (including, but not limited to, Mg, Ti and Al) refers to Ti by dividing it by the molar amount of Ti, which therefore is considered as a molar unit. Then, the total number of molar equivalents of cations to be satisfied is calculated, for example, by multiplying, respectively, the molar amount of Mg ⁺⁺ (related to Ti) by two, the molar amount of Ti ⁺⁴ (molar unit) by four and the molar amount of Al ⁺³ by three . The total value thus obtained is then compared with the sum of molar equivalents derived from anions, for example, Cl and OR groups, always relative to titanium. The difference resulting from this comparison, and in particular the negative balance obtained in terms of anionic molar equivalents, is denoted by the “LA factor”.

The “LA factor” is usually higher than 0.5, preferably higher than 1, and more preferably in the range of 1.5-6. Although examples departing from this trend are possible, it has been observed that in general, the higher the molar content of Al, the higher the “LA factor". It has also been found that the ratio “LA / Al + Ti”, where Al is the molar amount of Al with respect to Ti and Ti is the molar unit, is higher than 0.5, preferably higher than 0.7, and most preferably from 0.9 to 2. Without explanation as a limited interpretation of the invention, it is possible that the LA factor refers to the formation of compounds in which two or more metal atoms are connected by [-O-] bridges.

In addition to the above characteristics, the catalysts of the invention preferably show a porosity P _F determined by the mercury method, higher than 0.40 cm ³ / g and more preferably higher than 0.50 cm ³ / g, usually in the range 0.50-0.80 cm ³ / g The total porosity P _T may be in the range of 0.50-1.50 cm ³ / g, especially in the range of 0.60 and 1.20 cm ³ / g, and the difference (P _T -P _F ) may be higher than 0 , 10, preferably in the range of 0.15-0.50.

The surface area measured by the BET method is preferably lower than 80 and in particular between 10 and 70 m ² / g. The porosity measured by the BET method is typically between 0.10 and 0.50, preferably from 0.10 to 0.40 cm ³ / g.

In a preferred aspect, the catalyst component of the invention includes a Ti compound having at least a Ti-halogen bond, magnesium chloride and aluminum chloride, or more generally aluminum halide. As mentioned above, the catalytic component may also contain groups other than halogen, in any case in amounts lower than 0.5 moles for each mole of titanium and preferably lower than 0.3. Throughout this application, the term magnesium chloride means a magnesium compound having at least Mg-Cl bond, the term aluminum chloride means aluminum compound containing at least Al-Cl bond, and the term aluminum halide means aluminum compound containing, at least an Al — X bond, where X is Cl, Br or I.

In the catalyst component according to the invention, the average pore size for porosity due to pores up to 1 μm is in the range from 650 to 1200 Ǻ.

The particles of the solid component have a substantially spherical morphology and an average diameter of between 5 and 150 microns, preferably from 20 to 100 microns, and more preferably from 30 to 90 microns. Particles having essentially spherical morphology are those particles in which the ratio between the major axis and the smaller axis is equal to or lower than 1.5 and preferably lower than 1.3.

Magnesium chloride is preferably magnesium dichloride and is more preferably in active form, which means that it is characterized by an X-ray spectrum in which the most intense diffraction line that appears in the spectrum of inactive chloride (lattice constant equal to 2.56 Ǻ) decreases in intensity and expands to such an extent that it completely or partially merges with the profile of reflected waves incident on the lattice constant (d) of 2.95 Ǻ. When the merger is completed, the generated single wide peak has a maximum of intensity, which moves towards the corners lower than the corners of the most intense line.

The components of the invention may also include an electron-donor compound (internal donor) selected, for example, from ethers, esters, amines and ketones. Said compound is necessary when a component is used in the stereoregular (co) polymerization of olefins such as propylene, 1-butene, 4-methyl-pentene-1. In particular, the internal electron-donor compound can be selected from alkyl, cycloalkyl and aryl ethers and polycarboxylic acid esters, such as, for example, phthalic and maleic acid esters, in particular n-butyl phthalate, di-isobutyl phthalate, di-n- octyl phthalate.

Other predominantly used electron-donor compounds are simple 1,3-diesters, disclosed, in particular, in EP 361494, EP 361493 and EP 728769.

If an electron-donor compound is present, it is in a molar ratio relative to magnesium of between 1: 4 and 1:20.

Preferred titanium compounds have the formula Ti (OR ^I ) _n X _yn in which n is a number between 0 and 0.5 inclusive, y is the valency of titanium, R ^I has the meaning given above, and is preferably an alkyl, cycloalkyl radical or aryl containing 1-8 carbon atoms, and X is halogen. In particular, R ^I may be methyl, ethyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl, n-octyl and phenyl; X is preferably chlorine.

Aluminum halide can be selected from halides of the formula AlXL ₂ , where X is halogen, as previously defined, and L may independently represent OR ^I groups, as defined above, or halogen.

Preferably, the aluminum halide is aluminum chloride of the formula AlClL ₂ , where L may independently represent OR ^I groups, as defined above, or chlorine. Preferably L is chlorine. However, as mentioned above, it is also possible the presence of cyclic types containing a repeating unit of the formula - [ML _v-2 -O] _p -, in which M is independently Al or Ti, v is a valency of M, p is at least 2 and L has the meaning set forth above, and is preferably chlorine, and the presence of linear types of the formula ML _v-1 -O- [ML _v-2 O-] _n -ML _v-1 , in which M, L and v have the meaning, set forth above, and n is from 0 to 10. Preferably in the last formula, M is Al and L is Cl. Also preferred are the types of formula ROAlCl- [AlClO-] AlCl ₂ .

The catalyst according to the invention can be obtained in accordance with several methods. One of the preferred methods includes step (a) in which the compound MgCl ₂ · mR ^II OH tH ₂ O, in which 0.3 ≤ m ≤ 1.7, t is from 0.01 to 0.6 and R ^II represents an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, interacts with a titanium compound of the formula Ti (OR ^I ) _n X _yn , in which n is between 0 and 0.5, y is the valence of titanium, X is a halogen and R ^I has the meaning given above and preferably represents an alkyl radical containing 1-8 carbon atoms in the presence of aluminum compounds formula AlL _3, where L groups can be independently OR ^I, as defined above, or halogen. Preferably, at least one L is chlorine, more preferably two L is chlorine, and most preferably all L is chlorine.

In this case, MgCl ₂ · mR ^II OH tH ₂ O is the starting material for Mg dihalide. This type of compounds can usually be obtained by mixing alcohol and magnesium chloride in the presence of an inert hydrocarbon immiscible with the adduct, performing the action under stirring conditions at the melting point of the adduct (100-130 ° C). The emulsion is then rapidly cooled, thereby causing crystallization of the adduct in the form of spherical particles. Presents methods for producing these spherical adducts are reported, for example, in USP 4469648, USP 4399054 and WO 98/44009. Another suitable method for the formation of spherulites is by irrigation cooling, as described, for example, in USP 5100849 and 4829034. Adducts having the desired final alcohol content can be obtained by directly applying the selected amount of alcohol directly during the preparation of the adduct. However, if you want to obtain adducts with increased porosity, it is convenient to first prepare the adducts with more than 1.7 moles of alcohol per mole of MgCl ₂ and then subject them to a process of thermal and / or chemical dealcoholization. The process of thermal dealcoholization is carried out in a stream of nitrogen at temperatures between 50 and 150 ° C, until the alcohol content drops to a value ranging from 0.3 to 1.7. A process of this type is described in EP 395083.

Typically, these dealcoholized adducts are also characterized by porosity (measured by the mercury method), due to pores with a radius of up to 0.1 μm, ranging from 0.15 to 2.5 cm ³ / g, preferably from 0.25 to 1.5 cm ³ / g.

In the interaction of step (a), the Ti / Mg molar ratio is stoichiometric or higher; preferably this ratio is higher than 3. Even more preferably, a large excess of the titanium compound is used. Preferred titanium compounds are titanium tetrahalides, in particular TiCl ₄ . The reaction with the Ti compound can be carried out by suspending the adduct in cold TiCl ₄ (typically 0 ° C); the mixture is heated to 80-140 ° and maintained at this temperature for 0.5-5 hours. Preferably, the interaction times at the upper end of the interval are suitable in accordance with the temperature of the interaction at the lower end of the interval. Excess titanium compounds can be separated at high temperatures by filtration or precipitation and siphoning. As mentioned above, the interaction is carried out in the presence of an aluminum compound mentioned above, preferably AlCl ₃ , which is used in amounts such that the Mg / Al molar ratio can range from 1 to 35, preferably from 3 to 30, more preferably from 4 to 20 and most preferably in the range of 4-16. Reconstituted and washed in accordance with traditional technologies, the catalytic component is already capable of exhibiting the satisfactory characteristics disclosed above. However, it was found that nevertheless improved characteristics can be obtained when, in the second step (b) of the process, the solid product obtained in step (a) is subjected to a heat treatment carried out at temperatures higher than 50 ° C, preferably higher than 70 ° C, more preferably higher than 100 ° C, especially higher than 120 ° C and most preferably higher than 130 ° C. Temperatures at the lower end of the range are particularly preferred when using AlCl ₂ OR compounds in which R is a branched alkyl group.

Heat treatment can be carried out in several ways. According to one of them, the solid obtained in step (a) is suspended in an inert solvent such as a hydrocarbon and then subjected to heating, while maintaining the mixing of the system.

According to an alternative technology, the solid can be heated in the dry state by placing it in a device having heating walls with a jacket. While stirring can be provided by means of mechanical stirrers located inside said device, it is preferable to cause stirring through the use of rotating devices.

According to another different embodiment, the solid obtained in (a) can be heated by exposing it to a stream of hot inert gas such as nitrogen, preferably keeping the solid under fluidization conditions.

According to a further embodiment, heating is provided by further reacting with an excess of the titanium compound conducted at said high temperatures.

The heating time is not fixed, but may also vary depending on other conditions, such as the maximum temperature reached. As a rule, it ranges from 0.1 to 10 hours, more specifically from 0.5 to 6 hours. Usually, higher temperatures make it possible to shorten the heating time, while, conversely, lower temperatures may require longer reaction times.

In accordance with another embodiment, the catalyst of the invention can be obtained through the first step (a), in which the compound MgCl ₂ · mR ^II OH tH ₂ O, in which 0.3 ≤ m ≤ 1.7, t is from 0.01 to 0.6 and R ^II represents an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, interacts with a titanium compound of the formula Ti (OR ^I ) _n X _yn , in which n is between 0 and 0.5, y is a valency titanium, X is halogen and R ^I has the same meaning as above and the second step (b), in which the solid product obtained in (a) interacts again with the titanium compound in the presence of an aluminum compound of the formula AlL ₃ , where L can independently be OR ^I groups as defined above, or halogen or chlorine, preferably AlClL ₂ .

If desired, after this step (b), the solid product can be subjected to heat treatment in accordance with any one of the methods and conditions described above.

In conclusion, in accordance with yet another different process, solid catalyst components are prepared by a process comprising the step of (a), wherein a MgCl ₂ · mR ^II OH tH ₂ O compound in which 0.3 ≤ m ≤ 1.7, t is from 0.01 to 0.6 and R ^II represents an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, interacts with a titanium compound of the formula Ti (OR ^I ) _n X _yn , in which n is between 0 and 0, 5, y is the valence of titanium, X is halogen, and R ^I has the meaning given above; and the second stage (b), in which the solid product obtained in stage (a) is subjected to heat treatment in the presence of an aluminum compound of the formula AlL ₃ , where L may independently be OR ^I groups, as defined above, or halogen. Preferably, at least one L is chlorine according to the formula, preferably AlClL ₂ . The specified heat treatment should be carried out in accordance with any one of the methods or conditions described above.

Whatever method is used to produce the solid catalyst component of the invention, it has been found advantageous to carry out a final catalyst treatment comprising contacting said solid catalyst component with an electron-donor compound, preferably selected from ethers, ketones, esters and silicon compounds. Preferably, said electron-donor compound is selected from diesters and diketones, and more preferably from 1,3-diesters.

Preferred diesters are 9,9-dimethoxyfluorene and 1,3-diesters mentioned in EP 728769, of which 9.9-bis (methoxymethyl) fluorene is preferred. Of the ketones, aliphatic diketones are preferred, and of these, acetylacetone is most preferred. The contact is preferably carried out in an inert hydrocarbon as solvent at a temperature ranging from room temperature to the boiling point of the donor, usually from 40 to 150 ° C and preferably from 50 to 140 ° C. The electron donor compound can be used in a molar ratio with the Ti compound in the solid catalyst component obtained in stage (b), ranging from 5 to 0.01, preferably from 1 to 0.1, and more preferably from 0.8 to 0 ,one. The donor becomes fixed on the catalyst in variable amounts, which, as it turned out, do not correlate with the effect on morphological stability, i.e. with the ability of the catalyst to produce polymers with high bulk density even under the required test conditions applied by the applicant. In fact, a positive effect on morphological stability is always present, even when the amount of fixed donor is very low or possibly absent. In particular, donor treatment allows the catalyst to have even greater morphological stability, confirmed by the fact that a polymer with a high bulk density is also obtained by polymerizing ethylene in the presence of a large amount of hydrogen and using triethyl aluminum as a joint catalyst, which are known as extremely demanding conditions.

The catalyst components of the invention, whatever their preparation method, form catalysts for the polymerization of alpha-olefins CH ₂ = CHR ^III , where R ^III is hydrogen or a hydrocarbon radical containing 1-12 carbon atoms, by reaction with Al-alkyl compounds. Particularly preferred are Al-trialkyl compounds, for example Al-trimethyl, Al-triethyl, Al-tri-n-butyl, Al-triisobutyl. The Al / Ti ratio is higher than 1 and is typically between 5 and 800.

In the case of stereoregular polymerization of α-olefins, such as, for example, propylene and 1-butene, the preparation of the catalyst also typically uses an electron-donor compound (external donor), which may be the same or different from the compound used as internal donor.

When the internal donor is a polycarboxylic acid ester, in particular phthalate, the external donor is preferably selected from silane compounds containing at least a Si-OR bond having the formula R ^IX _4-n Si (OR ^X ) _n in which R ^IX is an alkyl, cycloalkyl, aryl radical having 1-18 carbon atoms, R ^X is an alkyl radical containing 1-4 carbon atoms and n is a number comprised between 1 and 3. Examples of these silanes are methyl cyclohexyl dimethoxysilane, difenildimetoksisila Methyl-t-butyl-dimethoxysilane, dicyclopentyldimethoxysilane.

Perhaps the predominant use of simple 1,3-diesters having the previously described formula. In the case in which one of these diesters is the internal donor, the use of an external donor can be avoided, since the stereoregularity of the catalyst is already quite high.

The spherical components of the invention and the catalysts obtained from them are used in methods for producing certain types of olefin polymers.

As mentioned above, the catalyst of the invention is endowed with particularly high morphological stability at a high hydrogen concentration to produce a low molecular weight ethylene (co) polymer. Thus, they are especially suitable for use in cascade or sequential polymerization processes, in the production of ethylene polymers with a wide molecular weight distribution both in suspension and in the gas phase. Typically, the catalyst can be used to produce: high density ethylene copolymers (HDPE having a density higher than 0.940 g / cm ³ ), including ethylene homopolymers and ethylene copolymers with alpha-olefins containing 3-12 carbon atoms; linear low density polyethylene (LLDPE having a density lower than 0.940 g / cm ³ ) and very low density and ultra low density polymers (VLDPE and ULDPE having a density lower than 0.942 g / cm ³ to 0.880 g / cm ³ ) consisting of copolymers ethylene with one or more alpha olefins containing from 3 to 12 carbon atoms, having a molar content of units derived from ethylene, higher than 80%; elastomeric copolymers of ethylene and propylene and elastomeric terpolymers of ethylene and propylene with small amounts of diene having a mass content of units derived from ethylene, comprising between about 30 and 70%, isotactic polypropylenes and crystalline copolymers of propylene and ethylene and / or other alpha-olefins having the content of units derived from propylene is higher than 85% wt .; impact resistant polymers of propylene obtained by sequential polymerization of propylene and mixtures of propylene with ethylene containing up to 30% wt. ethylene; copolymers of propylene and 1-butene having a number of units derived from 1-butene, comprising between 10 and 40% wt.

However, as previously indicated, they are particularly suitable for the production of polymers with a wide MMP and, in particular, homopolymers and copolymers of ethylene with a wide MMP containing up to 20% moles of higher α-olefins, such as propylene, 1-butene, 1-hexene , 1-octene.

One additional advantage of the catalyst described in this application is that it can be used as such in the polymerization process by introducing it directly into the reactor without the need for preliminary polymerization. This simplifies the design of the plant and provides an easier way to obtain a catalyst.

The main polymerization process in the presence of catalysts obtained from the catalytic components of the invention can be carried out in accordance with known technologies in either the liquid or gas phase, using, for example, the known fluidized bed technology or under conditions in which the polymer is mechanically mixed. However, the preferred method is carried out in a gas phase fluidized bed reactor. Whatever method is used, the catalyst described above, from the point of view of satisfactory morphological stability of its particles, can withstand polymerization temperatures higher than standard temperatures that are higher than 80 ° C and, in particular, in the range of 85-100 ° C. Since higher polymerization temperatures make it possible to simultaneously achieve a higher yield and more efficient heat removal due to the higher difference between the polymerization temperature and the cooling fluid, this leads to a significant increase in the productivity of the polymerization plant in the case of the catalyst according to the invention.

Examples of gas phase processes in which the use of the spherical components of the invention is possible are described in WO 92/21706, USP 5733987 and WO 93/03078. In these methods, the preliminary contact stage of the catalytic components, the preliminary polymerization stage and the gas phase polymerization stage in one or more reactors in series of fluidized or mechanically mixed bed are included, even if, as mentioned above, they do not strictly require the catalysts of the invention.

Therefore, in the case where the polymerization proceeds in the gas phase, the method of the invention is preferably carried out in accordance with the following steps:

(a) contacting the catalyst components in the absence of a polymerizable olefin or optionally in the presence of said olefin in an amount of not more than 20 g per gram of solid component (A);

(b) gas phase polymerization of ethylene or its mixtures with α-olefins CH ₂ = CHR, in which R is a hydrocarbon radical containing 1-10 carbon atoms in one or more fluidized or mechanically stirred bed reactors using a catalyst system obtained in (a).

As mentioned above, to further expand the MMP of the product, the method of the invention can be carried out in two or more reactors operating under different conditions and optionally by recycling at least partially the polymer that forms in the second reactor to the first reactor. Typically, two or more reactors operate with different concentrations of the molecular weight regulator or at different polymerization temperatures, or with both. Preferably, the polymerization is carried out in one or more stages, operating with various concentrations of the molecular weight regulator.

As already explained, one of the most interesting features of the catalysts described above is the ability to produce ethylene polymers with a low molecular weight, expressed by a high value of the melting index "E", and satisfactory morphological properties, expressed by high values of bulk density. In particular, these ethylene polymers have a melting index E higher than 50 and bulk densities higher than 0.35. Particularly preferred are those which have MI ”E” higher than 70 and bulk density higher than 0.37, and most preferred are those that have MI ”E” in the range of 80-400 and bulk density in the range of 0.4-0 , 6. When this type of polymers is obtained in the low molecular weight polymerization step of a multi-stage process, they make it possible to obtain ethylene polymers having at the same time a wide MMP, usually a pronounced melt flow ratio (F / P) of more than 20, preferably more than 25, and more preferably over 35, which is the ratio between the melt index measured with a load of 21.6 kg (melt index F) and the melt index measured with a load of 5 kg (melt index P), determined at 190 ° C in accordance with ASTM D-1238, bulk density greater than 0.44, preferably greater than 0.46, and preferably satisfactory homogeneity, expressed as the number of gels (determined by the method described below) having a diameter greater than 0.2 mm, lower than 70, and preferably lower than 60. In addition, preferably the films do not contain gels with a diameter higher than 0.5 mm. Once applied in the production of films or pipes, the polymers undoubtedly showed very good processability, while the extruded products showed a very low amount of gel. The polymer is obtained in the form of spherical particles, meaning that the ratio between the major axis and the smaller axis is equal to or lower than 1.5 and preferably lower than 1.3.

The following examples are provided for further description, and do not limit the present invention.

Properties are defined in accordance with the following methods.

Porosity and surface area using nitrogen are determined by the BET method (used SORPTOMATIC 1900 instrument from Carlo Erba).

Mercury porosity and surface area

Measurement is performed using the “2000 Series Porosimeter” from Carlo Erba.

Porosity is determined by absorption of mercury under pressure. For this determination, a calibrated dilatometer (3 mm diameter) CD ₃ (Carlo Erba) is used, connected to a mercury tank and to a high-vacuum pump (1 · 10 ^-2 mbar). A weighted amount of sample is placed in the dilatometer. Then the device is placed under high vacuum (<0.1 mm Hg) and incubated under these conditions for 20 minutes. The dilatometer is then connected to the mercury tank and the mercury is allowed to slowly flow into it until it reaches the level noted on the dilatometer at a height of 10 cm. The valve that connects the dilatometer and the vacuum pump closes, and then the mercury pressure gradually increases using nitrogen up to 140 kg / cm ² . Under the influence of pressure, mercury enters the pores, and the level decreases in accordance with the porosity of the material.

Porosity (cm ³ / g), both total and porosity due to pores up to 1 μm, pore distribution curve and average pore size are directly calculated from the integrated pore distribution curve, which is a function of reducing the volume of mercury and the applied pressure (all these data are provided and produced by a computer connected to the porosimeter that is equipped with the “MILESTONE 200 / 2.04” program from C. Erba).

MIE Flow Rate: ASTM D-1238 State E MIF Flow Rate: ASTM D-1238 State F MIP Flow Rate: ASTM D-1238 State P Bulk Density: DIN-53194

Ti definition ^(red)

0.5 g of the sample in powder form is dissolved in 100 ml of 2.7 M HCl in the presence of solid CO ₂ . The solution thus obtained is then subjected to volumetric titration with a solution of 0.1 N FeNH ₄ (SO ₄ ) ₂ · 12H ₂ O in the presence of solid CO ₂ used as an indicator of the equivalent point of NH ₄ SCN (25% aqueous solution). Stoichiometric calculations based on the volume of spent titratable agent give a mass amount of Ti ³⁺ in the sample.

The determination of Mg, Ti _(tot) and Al was carried out by plasma-induced emission spectroscopy (ICP) on an “ICP SPECTROMETER ARL Accuris”.

The sample was obtained by analytical weighing in a "flowing" platinum crucible "0.1-0.3 g of catalyst and 3 g of a mixture of lithium metaborate and tetraborate in a ratio of 1/1. The crucible is placed on a Bunsen burner with a low flame for the burning stage, and then after adding a few drops of KI solution, they are inserted into a special Claisse Fluxy device for complete combustion. The precipitate was collected using 5% v / v. HNO ₃ solution and then analyzed by ICP at the following wavelength:

Magnesium, 279.08 nm; titanium, 368.52 nm; aluminum, 394.40 nm.

Cl was determined by potentiometric titration.

Determination of OR groups : by gas chromatographic analysis.

Determination of the amount of gel : an additive was made from Irganox 168 (0.15 wt.%), ZnO (0.15 wt.%), Zinc stearate (0.05 wt.%), PPA-VITOW Z100 (0.03 wt.%) ), mixed with 45 kg of polymer and granulated using an extruder with two screws (WP (Werner & Pfliderer) ZSK 40 with a gear pump with a water granulator, maintaining the temperature at 230 ° C in all areas at a production rate of 38 kg / h. Then the product is extruded into blown film using an extruder Dolci KRC 40 based on a grooved loading device with an accumulation temperature curve of 220-225-225-220 ° C and 230-230 ° C in the areas of the mold. is 28 kg / h at 50 rpm The film is extruded with a blow-up ratio (BUR) of 4: 1 and a neck length of 7.5: 1 at a thickness of 20 microns. The gel amount per m ² is determined by visual determination of the gel having a size of a longer axis higher than 0.2 mm, on a piece of extruded film (size 25 × 7.5 cm), which is projected by the projector on a wall chart with an enlarged scale. Counting is done on 5 different pieces of the same film, and the final amount is given by the expression No = A / S, where No is the amount of gel per m ² , A is the amount of gel counted on 5 pieces of film, and S represents the total surface in m ² 5 examined pieces of film.

Ethylene Polymerization: General Procedure A.

A stainless steel autoclave with a capacity of 4.5 l was used, equipped with a magnetic stirrer, a measuring device for temperature and pressure, a loading line for hexane, ethylene and hydrogen, and purified with fluxing pure nitrogen at 70 ° C for 60 minutes. Then, at a temperature of 30 ° C, a solution of 1550 cm ^{3 of} hexane containing 7.7 cm ^{3 of} 10% w / v was introduced in a stream of nitrogen. TiBAL / Hexane. 50 cm ^{3 of} anhydrous hexane, 1 cm ³ 10% w / v were gradually introduced into a separate round-bottom glass flask with a capacity of 200 cm ³ . a solution of TiBAL / hexane and 0.040-0.070 g of the solid catalyst from table 1. They were mixed together, aged 10 minutes at room temperature and introduced into the reactor in a stream of nitrogen. The autoclave was closed, then the temperature was raised to 85 ° C, hydrogen (partial pressure 9 bar) and ethylene (partial pressure 3.0 bar) were added.

With constant stirring, the total pressure was maintained at 85 ° C for 120 minutes by feeding ethylene. At the end, the pressure was released in the reactor, and the temperature dropped to 30 ° C. The recovered polymer was dried at 70 ° C in a stream of nitrogen and analyzed. The results are presented in table 2.

Basic Ethylene Polymerization Procedure (Procedure B)

The procedure is carried out under the same conditions disclosed for procedure (A), with one difference that triethylaluminum is used instead of triisobutylaluminum.

EXAMPLES

OBTAINING A SPHERICAL SUBSTRATE (MgCl ₂ / EtOH ADDUCT)

Magnesium chloride and alcohol adduct were prepared following the method described in Example 2 of USP 4399054, but operating at 2000 rpm instead of 10000 rpm. The adduct contained approximately 3 moles of alcohol and 3.1 wt.% H ₂ O and had an average size of approximately 70 μm. The adduct was subjected to heat treatment in a stream of nitrogen in excess of the temperature range of 50-150 ° C until then, until it reached the mass content of alcohol 25%.

EXAMPLE 1

Obtaining a solid component

Into a 450-ml four-necked round flask flushed with nitrogen, 300 ml of TiCl ₄ and 1.34 g of anhydrous AlCl ₃ were introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 20.9 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Was added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C. in 100 minutes and maintained for 120 minutes. Then the temperature was reduced to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. Then the solid precipitate was washed five times with hexane at 60 ° C, once at room temperature and then dried under vacuum at 30 ° C.

Into a four-necked round flask with a capacity of 250 cm ³ purged with nitrogen, 120 cm ^{3 of} Isopar-L and 12.0 g of the previously obtained solid component were introduced at 25 ° C. With stirring, the temperature was raised to 130 ° C in 45 minutes and maintained for 5 hours. Then the temperature was lowered to 80 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed each twice with 100 cm ^{3 of} anhydrous hexane at 25 ° C. Finally, the solid was dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 2

a) In a four-necked round flask with a capacity of 1 l, purged with nitrogen, 715 ml of TiCl ₄ and 6.30 g of anhydrous AlCl ₃ were introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 56.5 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Was added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C. in 120 minutes and maintained for 120 minutes. Then the temperature was lowered to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. Then the solid precipitate was washed five times with hexane at 60 ° C, once at room temperature and then dried under vacuum at 30 ° C.

b) 100 cm ^{3 of} anhydrous heptane and 10.9 g of the previously obtained solid component were introduced into a four-necked round flask with a capacity of 300 cm ³ purged with nitrogen at 25 ° C. With stirring, the temperature was raised to 98 ° C in 20 minutes and maintained for 3 hours. Then the temperature was lowered to 90 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed once with 100 cm ^{3 of} anhydrous hexane at 25 ° C and finally dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 3

Into a four-necked round flask with a capacity of 250 cm ³ purged with nitrogen, 92 cm ^{3 of} anhydrous heptane and 9.2 g of the solid component of Example 2a) were introduced at 25 ° C. With stirring, the temperature was raised to 90 ° C in 20 minutes and maintained for 5 hours. Then the stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed once with 100 cm ^{3 of} anhydrous hexane at 25 ° C and finally dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 4

Into a 450-ml four-necked round flask flushed with nitrogen, 310 ml of TiCl ₄ and 2.35 g of anhydrous AlCl ₃ were introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 21.7 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Was added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C. in 100 minutes and maintained for 120 minutes. Then the temperature was lowered to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. Then the solid precipitate was washed five times with hexane at 60 ° C, once at room temperature and then dried under vacuum at 30 ° C.

Into a four-necked round flask with a capacity of 250 cm ³ flushed with nitrogen, 135 cm ^{3 of} Isopar-L and 13.5 g of the previously obtained solid component were introduced at 25 ° C. With stirring, the temperature was raised to 170 ° C in 45 minutes and maintained for 1 hour. Then the temperature was lowered to 80 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed twice every 100 cm ^{3 of} anhydrous hexane at 25 ° C and finally dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 5

a) In a four-necked glass reactor with a capacity of 1.5 l, purged with nitrogen, 950 ml of TiCl ₄ and 7.07 g of anhydrous AlCl ₃ were introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 66.8 g of a spherical MgCl ₂ / EtOH adduct containing 25% wt. Was added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C. in 100 minutes and maintained for 120 minutes. Then the temperature was lowered to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. Then the solid precipitate was washed five times with hexane at 60 ° C, once at room temperature and then dried under vacuum at 30 ° C.

b) Into a four-necked round flask with a capacity of 200 cm ³ purged with nitrogen, 110 cm ^{3 of} anhydrous Isopar-L and 11.1 g of the solid component a) obtained previously were introduced at 25 ° C. With stirring, the temperature was raised to 130 ° C in 30 minutes and maintained for 5 hours. Then the temperature was lowered to 80 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed three times with each 100 cm ^{3 of} anhydrous hexane at 25 ° C and finally dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 6

a) In a four-necked glass reactor with a capacity of 1.5 l, purged with nitrogen, 1 l of TiCl ₄ was introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 12.5 g of anhydrous AlCl ₃ and 100 g of a spherical adduct MgCl ₂ / EtOH containing 25 wt% were added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C. in 120 minutes and maintained for 120 minutes. Then the temperature was lowered to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 60 minutes, and the supernatant was siphoned. Then, the solid precipitate was washed seven times with hexane at 60 ° C and then dried under vacuum at 30 ° C.

b) The solid product thus obtained was introduced into a 1000 cm ³ four-necked round flask flushed with nitrogen and connected to a “rotary vacuum evaporator” system maintained in a nitrogen atmosphere. The temperature of the oil bath was set at 145 ° C and the rotational speed of the rotary vacuum evaporator was set at 70 rpm. Then, supporting the rotation of the flask, it was immersed in an oil bath. After approximately 20 minutes, the internal temperature was raised to 140 ° C and maintained for 2 hours. At the end, the temperature was lowered to 25 ° C. and the solid was analyzed. The results are presented in table 1.

EXAMPLE 7

In a four-necked glass reactor with a capacity of 1.5 l, purged with nitrogen, 1 l of TiCl ₄ was introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 100 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Was added with stirring. ethanol and obtained as described above. The temperature was raised to 130 ° C in 90 minutes and then lowered to 80 ° C. Maintaining the temperature at 80 ° C., 12.5 g of anhydrous AlCl _{3 was} added with stirring. Again, the temperature was raised to 135 ° C in 40 minutes and maintained with constant stirring for 5 hours. Then the temperature was lowered to 90 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. Then the solid precipitate was washed seven times with hexane at 60 ° C, then dried under vacuum at 30 ° C and analyzed. The results are presented in table 1.

EXAMPLE 8

In a four-necked glass reactor with a capacity of 500 cm ³ , purged with nitrogen, 300 cm ³ TiCl ₄ was introduced at 25 ° C and cooled to 0 ° C. At the same temperature, 2.6 g of anhydrous AlCl ₃ and 20.8 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Were added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C in 110 minutes and maintained with constant stirring for 2 hours. Then the temperature was lowered to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, the supernatant was siphoned and the solid was washed four times with heptane at 90 ° C. At the end, 200 cm ^{3 of} heptane was introduced, the temperature was raised to 97 ° C and maintained with constant stirring for 5 hours. Then the stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed four times with hexane at 60 ° C and then dried under vacuum at 30 ° C and analyzed. The results are presented in table 1.

EXAMPLE 9

a) In a four-necked round flask with a capacity of 2 l, purged with nitrogen, 1 l of TiCl ₄ was introduced at 0 ° C. Then, at the same temperature, 70 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Was added with stirring. ethanol and obtained as described above. The temperature was raised to 140 ° C. in 2 hours and maintained for 60 minutes. Then the stirring was stopped, the solid product was allowed to precipitate, and the supernatant was siphoned. The solid precipitate was washed once with heptane at 80 ° C and five times with hexane at 25 ° C and dried under vacuum at 30 ° C.

b) Into a four-necked round flask with a capacity of 350 cm ³ flushed with nitrogen, 220 cm ^{3 of} TiCl ₄ and 2.29 g of anhydrous AlCl ₃ were introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 21.5 g of the solid component a) obtained previously was introduced with stirring. The temperature was raised to 135 ° C in 45 minutes and maintained for 5 hours. Then the temperature was lowered to 80 ° C, stirring was stopped, the solid product was allowed to precipitate for 30 minutes, and the supernatant was siphoned. The solid precipitate was washed five times with hexane at 60 ° C and once at 25 ° C. Finally, the solid was dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 10

75 cm ^{3 of} anhydrous Isopar-L, 1.9 g of anhydrous AlCl ₃ and 15.0 g of the solid component of Example 9 a) obtained previously were introduced into a 200 cm ³ four-necked round flask flushed with nitrogen at 25 ° C. With stirring, the temperature was raised to 150 ° C in 30 minutes and maintained for 1 hour. Then the solid product was allowed to precipitate for 30 minutes and the supernatant siphoned. The solid precipitate was washed with 100 cm ^{3 of} heptane at 90 ° C and three times with anhydrous hexane at 25 ° C, finally dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 11

a) In a four-necked glass reactor with a capacity of 1.5 l, purged with nitrogen, 1 l of TiCl ₄ was introduced at 25 ° C and cooled to 0 ° C. Then, at the same temperature, 10.9 g of anhydrous AlCl ₃ and 100 g of a spherical adduct MgCl ₂ / EtOH containing 25% wt. Were added with stirring. ethanol and obtained as described above. The temperature was raised to 135 ° C. in 120 minutes and maintained for 120 minutes. Then the temperature was lowered to 130 ° C, stirring was stopped, the solid product was allowed to precipitate for 60 minutes, and the supernatant was siphoned. Then, the solid precipitate was washed seven times with hexane at 60 ° C and then dried under vacuum at 30 ° C.

b) 10 g of the solid product thus obtained and 100 ml of hexane were introduced at room temperature into a 250 cm ³ four-necked glass autoclave, purged with nitrogen. Then the autoclave was closed and the internal temperature was raised to 100 ° C and maintained for 5.5 hours. At the end, the temperature was lowered to 55 ° C, stirring was stopped, the solid product was allowed to precipitate for 10 minutes, and the supernatant was siphoned. The solid precipitate was washed with hexane at 25 ° C, then dried under vacuum at 30 ° C and analyzed. The results are presented in table 1.

EXAMPLE 12

Into a four-necked round flask with a capacity of 200 cm ³ , purged with nitrogen, 75 cm ^{3 of} anhydrous heptane, 17.2 ml of a heptane solution containing 14.2 mmoles of anhydrous AlCi ₂ OiPr, and 15.2 g of the solid component of Example 9 a were introduced at 25 ° C. ) received earlier. With stirring, the temperature was raised to 80 ° C in 20 minutes and maintained for 3 hours. Then the solid product was allowed to precipitate for 30 minutes and the supernatant siphoned. The solid precipitate was washed with 100 cm ^{3 of} heptane at 80 ° C and three times with anhydrous hexane at 25 ° C, finally dried under vacuum and analyzed. The results are presented in table 1.

EXAMPLE 13

The catalytic component was obtained in accordance with the same procedure disclosed in Example 7, with the difference that instead of AlCl ₃ , AlI ₃ was used in a molar ratio Mg / Al of 7.3. Characteristic results are presented in table 1.

EXAMPLE 14

A 500 ml four-necked round flask equipped with a mechanical stirrer and purged with nitrogen was charged at room temperature with 200 ml of anhydrous heptane and 2 g of the solid catalyst component obtained as described in Example 7. At the same temperature, an amount of acetylacetone was added dropwise with stirring to achieve a molar ratio of ED / Ti of 0.5. The temperature was raised to 50 ° C and the mixture was stirred for 3 hours. Then the stirring was stopped, the solid product was allowed to precipitate, and the supernatant was siphoned.

The solid precipitate was washed 3 times with anhydrous hexane (3 × 100 ml) at 25 ° C, recovered, dried under vacuum and analyzed. The final donor content was 0.1%. The polymerization results obtained by using it in the polymerization procedures of ethylene A and B described above are presented in table 2.

EXAMPLE 15

The catalyst component was obtained as described in example 14, with the difference that the processing temperature was 100 ° C. No donor was found in the final solid catalyst component. The polymerization results obtained by applying it to the ethylene B polymerization procedure described above are presented in Table 2.

EXAMPLE 16

The catalyst component was prepared as described in Example 14, with the difference that 9.9-bis (methoxymethyl) fluorene was used instead of acetylacetone. The final donor content was 1.2%. The polymerization results obtained by using it in the polymerization procedures of ethylene A and B described above are presented in table 2.

EXAMPLE 17

The catalyst component was obtained as described in example 16, with the difference that the processing temperature was 100 ° C. The final donor content was 1.2%. The polymerization results obtained by using it in the polymerization procedures of ethylene A and B described above are presented in table 2.

EXAMPLE 18

The catalyst component was prepared as described in Example 14, with the difference that 9.9-dimethoxyfluorene was used instead of acetylacetone. The final donor content was 0.1%. The polymerization results obtained by applying it to the ethylene A polymerization procedure described above are presented in Table 2.

COMPARATIVE EXAMPLE 1

The catalyst was prepared as described in Example 1 without the use of AlCl ₃ . The results are presented in table 1.

EXAMPLE 19

Obtaining PE with a wide MWD in a cascade polymerization process

The polymerization process was carried out at a plant operating continuously and essentially equipped with a small reactor (pre-contact boiler), in which the catalytic components are mixed to form a catalytic system, a second vessel collecting the catalytic system formed in the previous stage, also equipped with a mixing means, and two reactors with a fluidized bed ( polymerization reactors) , which are maintained under conditions of fluidization using propane.

The following reagents are loaded into the precontact boiler:

- solid catalytic component obtained as described in example 7,

- liquid propane as a solvent,

- a solution of alkylaluminum compounds.

The temperature is in the range of 10-60 ° C, and the residence time (in the first and second vessel) ranges from 15 minutes to 2 hours. The catalyst system thus obtained was directly fed from the precontact section (first and second vessel) to the first gas phase fluidized bed reactor operating under the conditions shown in Table 1. The polymer obtained in the first gas phase reactor was then transferred in the second gas phase reactor, operating under the conditions shown in table 3.

The polymer discharged from the final reactor was first transferred to a stripping section and then dried at 70 ° C. in a stream of nitrogen and weighed. The polymer properties are presented in table 4.

EXAMPLE 20

The polymerization was carried out as described in example 19, with the difference that the catalyst obtained in accordance with the disclosure of example 17 was used. The results and conditions are presented in tables 3 and 4.

Table 1 Example Porosity (Hg method) Mg Ti Al Cl OR ¹ LA factor LA / (Al + Ti) P _f wt.% wt.% wt.% wt.% wt.% cm ³ / g one 18.5 5.2 1.3 67.1 0.3 1.84 1.28 0.611 2 17.5 5.7 2.1 65.8 1.4 2.21 1.33 0.534 3 17.7 5.7 2.2 67.1 1.8 2.08 1.23 0.559 four 18.3 4.7 2.1 65.9 <0.1 2.77 1,53 0.566 5 17.7 5,0 2.0 65.3 0.3 2.41 1.41 0.558 6 17.4 6.4 2,3 65.0 0.4 2.83 1.72 0.555 7 17.4 6.2 2.2 66.3 0.5 2.45 1.49 0.544 8 17.1 5.5 2.5 65.5 0.9 2,37 1.31 0.526 9 18,4 4.2 2.1 68.9 <0.1 1.77 0.94 0.515 10 17.7 4.0 2.5 63.0 1,0 3.27 1,63 0.502 eleven 18.2 4.9 2.1 65,4 2.5 2,39 1.35 0.532 12 17.9 5.1 2.1 64.7 - 0.530 13 16.6 5,4 2,8 66.9 - 1.79 0.94 0.526 Comparative one 19.0 6.4 66.7- 1.43 0.643

table 2 Example Polymerization procedure Exit Mie Bdp Polymer morphology kg PE / g rolled. dg / min g / cm ³ one A 5.5 114 0.378 Spherical 2 A 9.2 0.355 Spherical 3 A 7.6 0.342 Spherical four A 5,0 70 0.405 Spherical 5 A 5.2 70 0.392 Spherical 6 A 4.1 41 0.406 Spherical 7 A 5.7 162 0.376 Spherical 8 A 7.6 0.380 Spherical 9 A 5.1 106 0.346 Spherical 10 A 4.3 0.364 Spherical eleven A 6.8 139 0.347 Spherical 12 A 4.1 84 0.356 Spherical 13 A 8.8 110 0.365 Spherical fourteen A
B 4.1
3.2 74
95 0.402
0.3 Spherical
Spherical / shattered fifteen B 2.9 95 0.34 Spherical with some destruction 16 A
B 5.2
3.6 122
122 0.4
0.26 Spherical
Spherical / shattered 17 A
B 4.4
5,4 115
135 0.399
0.345 Spherical
Spherical eighteen A 5.8 108 0.393 Spherical Comparative. one A 13.6 113 0.269 Shattered

Table 3 Preliminary contact ^1st vessel ^2nd vessel Cat. (g / h) Type AlR ₃ AlR ₃ / Cat. (g / g) Time (min) T (° C) Time (min) T ° (° C) 10 Tiba 5 fourteen fifty 60 fifty 10 Tiba four fourteen fifty 60 fifty

Table 3 continued The first fluidized bed reactor C ₂ ^- (mol.%) H ₂ / C ₂ ^- (mol.) Time (hour) P, bar, etc. T (° C) Yield (kg / h) 9.3 3.8 1,6 24 75 70 7.8 3.9 2.0 24 75 66

Table 3 continued The second fluidized bed reactor Time (min) T (° C) P, bar, etc. C ₂ H ₄ (mol.%) H ₂ / C ₂ ^- (mol.) C6- / C2 + C6- (mol.) Yield (kg / h) 1,6 75 24 4.4 0,061 0,070 153 1.8 85 24 6.0 0,065 0,068 145

Table 4
Final polymer 19 twenty MIP (g / 10 ') 0.29 0.28 MIF / MIP 37.9 29.7 Bulk density (kg / dm ³ ) 0.463 0.487 Gel amount <0.2 170 120 0.5-0.7 3 8 0.7-1.5 0 0 > 1.5 0 0

Claims (15)

1. Catalytic components for the polymerization of olefins, including Ti, Mg, Al, Cl and optionally OR ¹ groups in which R ¹ is a C1-C20 hydrocarbon group optionally containing heteroatoms, up to the amount such as to obtain an OR ¹ / molar ratio Ti lower than 0.5, characterized in that essentially all of the titanium atoms are in a valency state of 4, that the porosity (P _F ), measured by the mercury method and due to pores with a radius equal to or lower than 1 μm, It is at least 0.30 cm ³ / g, and the molar e ratio Cl / Ti is lower than 29. 2. The solid catalyst component according to claim 1, wherein the porosity (P _F ) is higher than 0.40 cm ³ / g. 3. The solid catalyst component according to claim 1, wherein the Cl / Ti molar ratio is lower than 28. 4. The solid catalyst component according to claim 1, wherein the amount of Al is lower than the amount of Ti. 5. The solid catalyst component according to claim 1, further characterized by an "LA factor" higher than 0.5, where the "LA factor" is the molar equivalent of anions lacking to bind all molar equivalents of cations present in the solid catalyst component, which were not bound by the total molar equivalent of the anions present in the solid catalyst component, all molar equivalents of anions and cations being calculated with respect to the molar amount of Ti. 6. The solid catalyst component according to claim 1, further characterized by the ratio LA / (Al + Ti), where Al and Ti are presented in a molar amount with respect to the molar amount of Ti higher than 0.4. 7. The solid catalyst component according to claim 1, containing aluminum chloride, selected from the groups consisting of aluminum compounds of the formula AlClL ₂ , where L may independently represent OR ¹ groups, as defined in claim 1, or chlorine. 8. The method of producing the catalytic component according to claim 1, comprising stage (a), in which the compound MgCl ₂ · mR ^II OH tH ₂ O, in which 0,3≤m≤1,7, t is from 0.01 to 0 , 6 and R ^II represents an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, interacts with a titanium compound of the formula Ti (OR ^I ) _n X _yn , in which n is between 0 and 0.5, y is the valency of titanium , X is halogen and R is as defined in claim 1, in the presence of an aluminum compound of the formula AlL ₃ , where L may independently be OR ¹ groups in which R ^{1 is} constitutes a C1-C20 hydrocarbon group or halogen. 9. The method of claim 8, further comprising a second stage (b), in which the solid product obtained in stage (a) is subjected to heat treatment carried out at temperatures higher than 50 ° C, 10. The method of producing the catalytic component according to claim 1, comprising stage (a), in which the compound MgCl ₂ · mR ^II OH tH ₂ O, in which 0,3≤m≤1,7, t is from 0.01 to 0 , 6 and R ^II represents an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, interacts with a titanium compound of the formula Ti (OR ^I ) _n X _yn , in which n is between 0 and 0.5, y is the valence of titanium , X is halogen and R ^I has the same meaning given above, and the second stage (b), in which the solid product obtained in (a), interacts again with the specified a titanium compound in the presence of an aluminum compound of the formula AlL ₃ , where L may independently be OR ^I groups in which R ^I represents a C1-C20 hydrocarbon group or halogen. 11. The method for producing the catalytic component according to claim 1, comprising stage (a), in which the compound MgCl ₂ · mR ^II OH tH ₂ O, in which 0,3≤m≤1,7, t is from 0.01 to 0 , 6 and R ^II represents an alkyl, cycloalkyl or aryl radical containing 1-12 carbon atoms, interacts with a titanium compound of the formula Ti (OR ^I ) _n X _yn , in which n is between 0 and 0.5, y is the valence of titanium , X is halogen and R ¹ has the same meaning given above, and a second step (b), in which the solid product obtained in (a) is subjected to a thermal treatment the presence of the aluminum compound of the formula AlL _3, where L groups can be independently OR ^I, wherein R ^I is a C1-C20 hydrocarbon group or halogen. 12. The method according to any one of claims 8 to 11, characterized in that the catalyst comprising contacting said solid catalyst component with an electron-donor compound is preferably selected from ethers, ketones, esters and silicon compounds. 13. The method of polymerization of olefins, carried out in the presence of a catalytic system, comprising the product of the interaction of the solid catalytic component according to any one of claims 1 to 4 and an aluminum alkyl compound. 14. The method according to p. 13, characterized in that it is carried out in the gas phase. 15. The method according to 14, carried out in two or more reactors operating at different concentrations of the molecular weight regulator.