SE500045C2 - Prodn. method for catalyst precursor for polymerisation of alpha-olefins - involves inorganic oxide carrier, pref. silica, in inert liq. carbohydrate - Google Patents

Abstract

An inorganic oxide carrier is contacted with a magnesium dialkoxide, a solvent for magnesium dialkoxide, which involves a chlorinated alcohol as main constituent, and a titanium alkoxide. The carrier is chlorinated with a chlorinated medium and the chlorinated product is recovered to provide the catalyst precursor. As solvent for magnesium dialkoxide is used an additive to at most 2 mol/mol of magnesium dialkoxide of a chlorinated alcohol with the formula R"OH in which R" is a chlorinated 2-10C alkyl group, whereby the chlorinated alcohol is pref. 2,2,2-trichlorethanol. The magnesium dialkoxide used has the formula Mg(OR')2 in which R' is the same or two different 2-8C alkyl groups. The titanium alkoxide used has the formula Ti(OR''')4 in which R''' is the same or different 2-3C alkyl groups and the used titanium alkoxide is pref. titanium tetrabutoxide.

Description

SCJÛ 10 15 20 25 30 35 0115 2 remove solvents such as hydrocarbons, ethers, esters and alcohols.

An example of a time consuming production of a Ziegler-Natta catalyst is described in US 4,302,565.

Calcined silica is slurried in a hydrocarbon and treated in a first step with an aluminum alkyl, to block the hydroxyl groups on the surface of the silica. The treated silica dried to a fine powder. In the second step is added a complex of magnesium dichloride, titanium tetrachloride and tetrahydrofuran (THF). Slurry medium is THF. The impregnated silica is dried. In the third step, sludge the impregnated silica into a hydrocarbon afterwards the catalyst precursor is pre-activated with an aluminum alkyl.

The catalyst precursor thus prepared is then dried a free-flowing powder.

In the industrial manufacture of catalyst means 'each drying step a significant amount of time. It can further be difficult to remove the last traces of polar solutions solvent, and residual polar solvent residues inside the catalyst precursor may have a negative effect on its activity and properties. Residual solvent also entails a cost and entails that the price of the catalyst becomes high. Consequently, there is a need of a simplified and less time consuming production of Ziegler-Natta catalysts, in addition to which the use of polar solvents is reduced or eliminated row.

Characteristic of Ziegler-Natta catalysts with titanium as active metal is generally that they give a polymer with a relatively narrow molecular weight distribution (MWD). This is a advantage in certain contexts, for example in the production of ethylene homo- or gampolymers having a density above 940 kg / m ° and an enamel flow (Mraz 16) of 1-30 g / 10 min aan which are intended for injection molding purposes and shall have good impact resistance. Such polymers are usually prepared in one single-stage reactor of the so-called loop type or gas phase type. As examples of a suitable process for the preparation of 10 15 20 25 30 35 500 045 3 ethylene (co) polymers, with varying densities and melting flows, can be referred to FI 906 427.

In other contexts, such as in the production of bottles, cable jackets and tubes, is the narrow molecular weight distribution obtained with Ziegler-Natta catalyst with titanium as the active metal, however, a disadvantage of due to the poor flow properties and the poor workability. In these contexts, a medium width or broad molecular weight distribution desirable.

To produce olefin polymers with such a broad molecular weight distribution has long had to resort to so-called chromium catalysts. Such, however, exhibit others disadvantages, in that, for example, the molecular weight distribution is is consistent with the nature of the catalyst and cannot be worth through the reactor conditions. Furthermore, chromium- the poor hydrogen response of the catalysts, i.e. the polymer cooling weight can not be comfortably regulated by means of hydrogen additive in reactor as is the case with Ziegler-Natta catalysts.

Chromium catalysts also do not allow precise regulation of the comonomer distribution in the preparation of polymers.

In cases where polyethylene with a broad molecular weight distribution is desirable has it, to eliminate the problem with it narrow molecular weight distribution obtained with Ziegler-Nat ta catalysts and the disadvantages of chromium catalysts, proposed to carry out the polymerization in several steps using Ziegler-Natta catalysts, and thereby keep the polymerization conditions different in each step or reactor. The polyethylene formed can then be made to constitute a mixture of at least two different qualities with different melt flow / molecular weight distribution, whereby molecular the weight distribution of the mixture becomes wider than that of those the components separately. Is the molecular weight distribution the components of the components are sufficiently different, the molecular weight distribution curve for mixed to show two / several maxima, one has got a so-called bi (poly-) modal polyethylene. Furthermore, comonomer additives 500 Û45 10 15 20 25 30 35 4 as well as catalyst and cocatalyst additives are made different in the different stages, which provides further opportunities.

As an example of this technique can be mentioned Fl_Q§W§§7, describing a multi-step process for producing polyethylene with bimodal and / or wide MWD in a reactor section with a number of steps. The first step consists of po- lymerization in the liquid phase and the second / following step (s) carried out in at least one gas phase reactor. The liquid phase step is performed in a so-called loop reactor using a low-boiling hydrocarbon medium and with a residence time of at least ten minutes.

Preferably 35-90% of the total polymer is formed in it first step, at a temperature of 75-110 ° C and a pressure of 40-90 bar. The hydrogen / ethylene molar ratio varies from 0 to 1.0. This step is followed by at least one gas phase polymer. at a temperature of 50-115 ° C and an ethylene partial pressure of 4-2O bar, the hydrogen concentration being preferred is lower than in the first step. Furthermore, even comonomers during the gas phase polymerization.

Although the reference is not limited to any separate catalyst, Ziegler-Natta catalysts are preferred.

However, the process conditions impose certain requirements on lysator properties to achieve optimal benefits. At the production of relatively low molecular weight material in it The first step requires the addition of significant amounts of hydrogen to regulate the molecular growth of the polymer. This leads to that the activity of the catalyst is reduced, since the presence of hydrogen tends to lower the catalyst activity in polymer risation of ethylene. In the second stage of the polymerization, the The hydrogen is low and further in this step comonomer is added.

Both of these conditions help to provide a rapid catalyst activity, which may then be undesirable high.

Thus, if the catalyst has poor hydrogen sensitivity, it will have too much team activity in the first step.

On the other hand, it has a high level of activity already in the presence of hydrogen, productivity can increase too much in the other 10 15 20 25 30 35 500 045 5 step (gas phase polymerization) and may result in insufficient heat transfer with risk of melting and / or sintering the polymer. It is consequently desirable with a catalyst with balanced properties, i.e. sufficiently high activity in the presence of hydrogen, however not too high activity in the absence or at low hydrogen content and in the presence of comonomer. In addition, must catalyst must be productive from the outset of the polymer because the residence time in the first polymerization step is quite short. Furthermore, the catalyst must maintain their activity for a long time, as the holding time is long in the second (and possibly further the following) gas phase polymerization step.

It is an object of the present invention that provide a catalyst precursor, which, in addition to the is simple and inexpensive to manufacture and can be manufactured in one step without the use of large amounts of polar solution agents, such as THF, ethyl acetate or butanol, as solvents agents for the magnesium compound (usually magnesium dichloro- rid), when used for d-olefin polymerization in at least one step together with cocatalyst and possibly electron donor exhibits the above, sought after the properties, i.e. good hydrogen sensitivity combined with relatively good comonomer sensitivity and which maintains its activity for a long time from that of the polymerization beginning.

The object of the invention is achieved with a titanium-based catalyst precursor, which is prepared by impregnation of an inorganic oxide support, preferably silica, with a magnesium alkoxide dissolved in a chlorinated alcohol and a titanium alkoxide, followed by chlorination of the impregnated support pure, preferably with an alkylaluminum chloride.

The more detailed features of the invention appear from it the following description and of the claims.

As an example of prior art can be mentioned_g§ 5,093,443, which relates to the polymerization of α-olefins. veneer with a catalyst composition containing one ECO 045 10 15 20 25 30 35 6 chlorinated alcohol. According to this patent specification, a catalyst precursor by a solid support, such as silica, tactase with an organomagnesium compound of the formula RMgR ' (where R and R 'are the same or different C4-C12 alkyl groups), wherein the organomagnesium compound is preferably dioctylmagnesium. Then the mixture is contacted with one chlorinated alcohol, such as 2,2,2-trichloroethanol, and so on the resulting mixture is then contacted with at least one soluble metal compound, such as titanium tetrachloride, which is soluble in the non-polar solvent. This reference differs in a non-polar solvent such as hexane, from the present invention in several respects, for example by that a magnesium alkyl compound and titanium tetrachloride are used instead of a magnesium alkoxide and a titanium alkoxide oxide. (us 4,954,470 and us 4,849,389 are further examples of prior art similar to it, as above described U.S. patents.

Another example of prior art is EP 0 264 169, which relates to a procedure for the position of an ethylene-propylene copolymer rubber, and more particularly determined a catalyst composition for this. The catalyst prepared from an inorganic oxide support, such as silica, a dihydrocarbylmagnesium compound (wherein the hydrocarbyl groups are alkyl, cycloalkyl, aryl or aralkyl groups having 1-20 carbon atoms), a hydrocarbyloxy group-containing compound based on silicon, carbon, phosphorus, boron or aluminum, a halogen-containing alcohol and a titanium compound, titanium tetrachloride. Not in this case either a magnesium alkoxide or a titanium alkoxide is used, in the present invention.

The preparation of the catalyst precursor according to the invention and its use in α-olefin polymer sation will now be described in more detail, first a brief as description shall be given of the ingredients used for preparation of the precursor. 10 15 20 25 30 35 500 045 7 The inorganic oxide used as a carrier in the method according to the invention, should be dry and have a low content of hydroxyl groups on the surface. Because commercial products usually have their hydroxyl groups left on surface, they must generally be removed in connection with the method according to the invention. The removal takes place thermally and / or chemically. Typical inorganic oxide supports are silica, aluminum nitrous oxide, mixed oxides of silicon and aluminum, and other mixed silicates.

A preferred inorganic oxide is silica, i.e. silica. The heat treatment of silica takes place at lower temperatures. rations if you want to remove physically adsorbed water and at higher temperatures if you want to remove even mechanically bound water, i.e. surface hydroxyl groups, by calcination. The heat treatment is preferably performed at a temperature between about 130-100 ° C. According to a embodiment of the invention, the silica is first dried at a temperature of about 130-250 ° C to physically remove adsorbed water. The silica is then calcined at 600-1000 ° C to also remove the hydroxyl groups. This method is used especially if the silica is not chemically treated before the impregnation procedure to be described below. Silica, which has been pretreated by calcination in several hours at such a high temperature, contains very few hydroxyl groups on the surface. Chemical removal of surface hydroxyl groups on the silica support can be done using materials which react with hydroxyl groups. Such materials materials include organic silicon, aluminum, zinc, feed and / or fluorine compounds. Suitable hydroxy removal hexamethyldisilazane, triethylaluminum, diethylaluminum chloride, ethylaluminum dichloride and diethyl zinc.

The dried silica support is typically reacted with the hydroxy scavenger in a hydrocarbon slurry to convert the hydroxyl groups of the silica to oxygen bridges between the silica and the removing agent and preferably create a non-reducing surface on the silica support. Before fos- 500 045 10 15 20 25 30 35 8 the silica thus pretreated is impregnated as described below, the hydrocarbon solvent may removed together with any excess hydroxyl group removal agents. The described measures can also be used to remove surface hydroxyl groups from inorganic oxides other than silica.

A distinguishing feature of the present invention is that in the preparation of the catalyst precursor the magnesium compound used consists of a magnesium alkoxide. More specifically, the magnesium dialkoxide has the formula: Mg (OR ') 2 where R 'may represent one and the same or two different alkyl groups, preferably C2-C8 C2-C5 alkyl groups. As examples of particularly preferred alkyl groups, more preferably magnesium dialkoxides may be mentioned magnesium dietoxide (i.e. R '= ethyl group), magnesium diisopropoxide (R' = isopropyl- group) and magnesium di-n-propoxide (R '= propyl group).

A particularly distinctive feature of the invention is the use of a chlorinated alcohol, as a solvent for the solid magnesium dialkoxide. By using a claw- alcohol as a solvent, it has proved possible to reduce the amount of polar solvent very significantly.

The molar ratio of polar solvent / magnesium dialkoxide can then be kept as low as below 2.0, the amount polar solvent includes both the chlorinated alcohol hole and any additional polar solution added that titanium the tetraalkoxide, which is also added to the mixture, also average. In this respect, it deserves to be noted, helps to dissolve the magnesium dialkoxide, but without included in the amount of polar solvent. The obtained the mixture, containing magnesium and titanium alkoxides and chlorinated alcohol (and possibly another minor amount of non-chlorinated cosolvent) is added then silica. This can then either be in dry state, a substantially dry mixture 10 15 20 25 30 35 500 045 9 obtained, or, alternatively, be suspended in an inert hydrocarbon. This means that an impregnation step, with a slurry in a polar solvent, is not necessary. Only one impregnation step, which is performed mainly dry, or in an inert hydrocarbon, is needed.

This is a great advantage of the invention.

In addition to the fact that chlorinated alcohol is an effective active solvent for the magnesium alkoxide, it also has a some effect as a chlorinating agent. Given that it chlorinated alcohol may have a certain negative effect on lysator activity, may, if desired, a certain proportion of the chlorinated alcohol is exchanged for another co-solution agents, which may be selected from oxygen-containing, more or less polar organic solvents, such as THF or ethylene glycol. It should be noted that these co- when used, may not exceed 50 % by weight of the solvent and that the remainder of the solvent the magnesium alkoxide must be chlorinated alcohol. The one used as solvent in the invention, Chlorinated alcohol has the formula: R "0H wherein R "is a chlorinated C 2 -C 10 alkyl group, preferably one chlorinated C2-C4 alkyl group, and most preferably a chlorinated ethyl group. It is especially preferred that the chlorinated al- the carbon is 2,2,2-trichloroethanol. Examples of other suitable chlorinated alcohols are 2-chloroethanol, 2,2-dichloroethanol, 2-chloropropanol, 2,2-dichloropropanol, 2,2,3-trichloropropanol, 2,2,3,3-tetrachloropropanol, 2-chloro-1-butanol, 2,3-dichloro-1- -butanol, 2,3,4-trichloro-1-butanol, 2,3,4,4-tetrachloro-1-butanol tanol and 2,2,3,3,4,4-hexachloro-1-butanol.

Without being bound by any particular theory presumed that the high hydrogen response exhibited by the catalyst according to the invention, depends in whole or in part on the chlorinated alcohol. 500 045 10 15 20 25 30 35 10 Another feature of the invention is the use of the use of a titanium alkoxide as a starting material for catalytic the titanium content of the sator precursor. The titanium oxide may be one partial alkoxide of tetravalent titanium, but is preferably one titanium tetraalkoxide of the formula: Ti (OR ") 4 wherein R "'represents the same or different C 2 -C 8 alkyl groups, preferably C 2 -C 5 alkyl groups and most preferably C 3 -C 4 alkyl groups, such as in titanium tetrabutoxide.

As stated earlier, catalyst preparations are chlorinated. the cursor then with a chlorinating agent. This chlorine agents are selected from chlorine, and compounds thereof with elements of Group III-V of the Periodic Table. Typical claws agents are chlorine, boron trichloride, ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride, silicon tetrachloride and phosphorus trichloride. The most preferred The excipients are alkylaluminum chlorides, wherein the alkyl moiety contains 1-5 carbon atoms, such as dimethylaluminum chloride (DMAC), methylaluminum dichloride (MADC), ethylaluminum dichloride chloride (EADC), diethylaluminum chloride (DEAC), propylaluminum minium dichloride (PADC), etc. EADC is especially preferred. If the chlorinating agent, such as the preferred EADC, is added the carrier before it has been brought into contact with magnesium .oxide and titanium alkoxide, serve the chlorinating agent also to chemically remove silanol groups on the support surface.

The treatment of the support with the catalyst precursor other constituents take place in a manner known per se, dry or in an inert liquid hydrocarbon, preferably an aliphatic hydrocarbon having 4-10 carbon atoms, such as pentane, hexane and / or heptane. The hydrocarbons used are purified according to well-known methods before use in the manufacture of lysators. Pentane is preferred. 10 15 20 25 30 35 500 045 ll In the preparation of the catalyst precursor according to the present invention first selects a desired carrier, preferably silica, and is prepared, by its silanol groups, i.e. surface hydroxyl groups, mainly thing is removed by thermal or chemical treatment, such as described earlier. The carrier thus prepared then slurried in an inert, liquid hydrocarbon, after which treatment takes place with the other constituents of the sator precursor. In this treatment, magnesium the alkoxide, the chlorinated alcohol and the titanium alkoxide, were separately in that order, in admixture with each other, or first the magnesium alkoxide and the chlorinated alcohol and then the titanium oxide. The molar ratio between the the magnesium alkoxide and the added titanium alkoxide may vary, but it is preferred to have a molar ratio Mg: Ti of about 1-3: 1, preferably about 2: 1. The amount of chlorine row of alcohol should be sufficient to other components dissolve the magnesium alkoxide, but at most corresponding to 2.0 mol / mol Mg alkoxide. As mentioned earlier, a certain, smaller part of the chlorinated alcohol can be exchanged against a cosolvent, consisting of, for example, THF or ethylene glycol and in addition the titanium alkoxide can also help to dissolve the magnesium alkoxide. The obtained the slurry is stirred, preferably under heating, to a temperature of at most about 120 ° C, preferably about 60 ° C or less. Then the chlorinating agent is added, which This can be done directly to the slurry or after drying of the slurry and re-slurry in liquid carbon hydrogen (pentane). After completion of the chlorination treatment, the catalyst precursor by removing the slurry solvent, which is conveniently done by bubbling of clean and dry nitrogen gas. The chlorinating agent can also added first to the dried / calcined silica can. In this case, the chlorinating agent reacts with silica existing hydroxyl groups. Any surplus of chlorinating agent is adsorbed on the silica. The temperature is maintained during chlorination at a maximum of 120 ° C, usually below 500 045, 10 15 20 25 30 35 12 80 ° C. After addition of magnesium alkoxide and chlorinated alcohol and titanium alkoxide, wipe off the slurry medium using nitrogen gas. The resulting catalyst precursor is then ready to use with cocatalyst for the polymerization of α-olefins, preferably for the preparation of position of bimodal ethylene homo- or copolymers.

Conventional Ziegler catalysts are used as cocatalyst. Night catalyst activators, such as aluminum alkyls, e.g. aluminum trialkyls, chlorinated aluminum alkyls or aluminum alkyl hydrides. Preferred cocatalysts are e.g. trimethylaluminum (TMA), triethylaluminum (TEA) and dimer tylaluminum chloride (DMAC). Also dichloraluminum alkyls, as methylaluminum dichloride, may be used but is preferred not, as they provide lower activity. For suitable cocatalysts torer may be referred to John Boor Jr., "Ziegler-Natta Catalysts and Polymerizations ", Academic Press, New York (1979), pp. 81-88.

Use of the one prepared according to the invention the catalyst precursor for α-olefin polymerization takes place by conventional polymerization processes under conventional conditions. The polymerization reaction carried out in at least one step as polymerization in the liquid phase or in the gas phase. For the production of polymers with medium wide or wide MWD, it is preferred to perform polymer in two or more steps, the first step may be a liquid phase or gas phase polymerization, while the second and any subsequent steps preferably carried out in the gas phase. In the production of ethylene copolymers are added to the comonomer in any or several steps.

To further illustrate the invention is given below some non-limiting embodiments.

Melt flows (MFR2, MFR5, MFR21) have been determined according to ISO 1133. 10 15 20 25 30 35 500 045 13 Example The polymerizations were carried out according to any of the following general procedures: A. Homopolymerization The prepared catalyst precursors were used for polymerization as follows. A 5-liter autoclave off stainless steel, preheated to 90 ° C during rinsing with dry nitrogen, was filled at room temperature with 3 l of dry pentane. The closed reactor was heated and at 85 ° C TEA was added to a TEA: Ti molar ratio of 60: 1, hydrogen from a container with a pressure of 6.0 bar, and ethylene to a total pressure in the reactor of 12 bar. Reactional the mixture was stirred at a stirrer speed of 700 rpm my. The temperature was raised to 90 ° C and the polymerization continued for 90 min.

B. Copolymerization The prepared catalyst precursors were used for polymerization as follows. A 5-liter autoclave off stainless steel, preheated to 90 ° C during rinsing with dry nitrogen, was filled at room temperature with 3 l of dry pentane. The closed reactor was heated and at 85 ° C TEA was added to a TEA: Ti molar ratio of 60: 1, 120 ml of 1-hexene, hydrogen from a container with a pressure of 6.0 bar, and ethylene to a total pressure in the reactor of 12.0 bar. The reaction mixture was stirred at a stirrer speed . of 700 rpm. The temperature was raised to 90 ° C and the merisation was continued for 90 min.

C. Bimodal polymerization The prepared catalyst precursor was used for polymerization as follows. A 5-liter autoclave off stainless steel, preheated to 90 ° C during rinsing with dry nitrogen, was filled at room temperature with 3 l of dry pentane. The closed reactor was heated and at 70 ° C was added 8.1 ml of 11.2% TEA, hydrogen from a container with a pressure of 25 bar, and ethylene to a total pressure of 11.5 bar in the reactor. After consuming 347 g of ethylene the pressure was reduced to 2 bar and the reactor was pressurized with 500 045 10 15 20 25 30 35 14 nitrogen. Hydrogen was filled into the hydrogen container to a pressure of 1.0 bar hydrogen, the container for the mer was filled with 120 ml of 1-hexene. Hydrogen and comonomer was transported into the reactor using ethylene. Total- the pressure in the reactor was 11.5 bar. Ethylene consumption in it the second step was 358 g.

Example 1 Preparation of catalyst precursor 3.95 g of silica of quality 955 W 2 O, activated at 600 ° C, and 1.01 g (1.8 mmol / g silica) of magnesium diiso- propoxide was added under inert conditions to a 150 ml piston, which was provided with a septum, and to create one slurry was added 20 ml of n-pentane. Then added 0.341 ml (0.9 mmol / g silica) trichloroethanol and 0.198 ml (0.9 mmol / g silica) ethylene glycol at room temperature. Up- the slurry was heated to 50 ° C and stirred for 24 hours. Thereafter 1.21 g (0.9 mmol / g silica) of titanium tetrabutoxide were added the slurry. The slurry was stirred at 50 ° C for 30 minutes and then 9.50 ml of 25% EADC (3.6 mmol / g silica) was added.

The slurry was then stirred for 1 hour at 60 ° C. Final- The catalyst precursor was dried through the nitrogen gas. bubbling. The powder obtained was light brown and the composition of the lysator precursor was 4.4% by weight of Al, 15.9 wt% Cl, 2.0 wt% Mg and 2.0 wt% Ti.

Polymerization was performed according to method B above.

The results are shown in Table 1.

Example 2 Preparation of catalyst precursor 815 g silica of quality ES70X, 600 ° C, and 3.3 l of n-pentane was added to a 16 l of mixed tank. 0.249 l of 24.3% EADC (0.4 mmol / g silica) added was allowed to react with the silica for 2 hours at 35 ° C.

Then a solution of 186.5 magnesium dietoxide was added. 277.1 g of titanium tetrabutoxide and 60.9 g of trichloroethanol the slurry (2.0 mmol magnesium dietoxide / g silica; 1.0 mmol titanium abutoxide / g silica; 0.5 mmol trichloroethanol / g 1870 activated at silica). The slurry was stirred for 2 hours at 35 ° C. 10 15 20 25 30 35 500 045 15 24.3% EADC (3.0 mmol / g silica) was added to the mixture. tank and allowed to react for 2 hours at 50 ° C. Catalyst- the precursor was dried at 50 ° C under nitrogen bubbling.

The composition of the obtained catalyst precursor was: 4.4% by weight of Al; 14.2% by weight of Cl; 2.3 wt% Mg and 2.3 wt% Ti.

Polymerization was carried out according to method A resp. B above. The results are shown in Table 1.

Example 3 (comparative) A catalyst precursor prepared according to US 4 302 565, 2.3 wt% A1: 7.5 weight% Cl; 1.4 wt% Mg and 0.95 wt% Ti, were used for polymerization according to method B above. The result presented goes from table 1.

Example 4 Using the catalyst prepared in Example 2 and which had the composition: lysator precursor, the following polymerization was carried out in a gas phase reactor: The reactor temperature was 104 ° C and that of the reactor total pressure was 17.5 bar. The ethylene pressure in the reactor was 8.7 bar and the H2 / ethylene ratio was 0.85. The resulting poly- the ash content of the lake was 345 ppm. MFR2 was 184 g / 10 min and the ethane content was 0.4 vol%. The sieve analysis of the polymer was jande: 2.0 mm 0.4%: 0.8 mm 0.9%; 0.36 mm 28.5%; 0.25 mm 26.6%; 0.10 mm 33.4%; 0.07 mm 6.0%; grain tail (pan) 4.2%.

The result is also reported in Table 2.

Example 5 (comparative) The catalyst precursor of Example 3 was used for polymerization in a gas phase reactor. The reactor temperature was 104 ° C and the total pressure of the reactor was 17.5 bar. The ethylene pressure in the reactor was 6.7 bar and the H2 / ethylene ratio was 1.50.

The ash content of the resulting polymer was 1993 ppm. MFR2 was 178 g / 10 min and the ethane content was 1.0 vo1%. The polymer sieve lys was as follows: 2.0 mm 0.1%; 0.8 mm 0.9%; 0.36 mm 21.8%: 0.25 mm 44.9%; 0.10 mm 29.1%; 0.07 mm 3.0%; (pan) 0.3%. The result is also reported in Table 2. grain tail 10 15 20 25 30 35 16 Example 6 Preparation of catalyst precursor 25 g silica of quality ES70X, activated at 600 ° C, and 5.72 g (2.0 mmol / g silica) of magnesium ethoxide was added to a 1 L reactor under inert conditions. 100 ml of n-heptane was added to create a slurry. At room temperature was then added 7.20 ml (3.0 mmol / g silica) trichloroethanol and 0.70 ml (0.5 mmol / g silica) ethylene glycol. The slurry was heated to 97 ° C and stirred for 6 hours. Then 8.52 g (1.0 mmol / g silica) was added titanium tetrabutoxide to the slurry and the whole was stirred 1 h. The catalyst precursor was then dried through nitrogen bubbling, whereby a yellow powder was obtained. This pulse was suspended in n-pentane and 66.82 ml of 25% EADC (4.0) mmol / g silica) was added. After 1 hour at 36 ° C it was dried the catalyst precursor by nitrogen gas bubbling. Cataly the composition of the sator precursor was: 4.2% by weight of Al; 23.6 wt% Cl: 1.9 wt% Mg and 1.9 wt% Ti.

Polymerization was carried out according to method B above.

The result is shown in Table 1. 3 Example 7 Preparation of catalyst precursor To a 150 ml flask, fitted with a septum, and containing land 8.36 g silica, of quality '955 W 20, activated at 200 ° C, 8.48 g of 25% (2.0 mmol / g of silica) EADC was added.

This was allowed to react for 1.5 hours at 40 ° C. 7.2 g n-pen- solution containing magnesium diethoxide, titanium tetra- butoxide and trichloroethanol were added dropwise to the traded silica. The molar ratio of magnesium dietoxide to titanium tetrabutoxide to trichloroethanol was 2.0: 1.0: 0, S. 25 ml of n-pentane were added to form a slurry and 6.36 g of 25% EADC (1.5 mmol / g silica) were allowed to react with the impregnated silica. Finally, the catalyst was dried. the precursor under nitrogen. It then had a composition ningen 4.5 vika A1; 14.4 vika cl; 2.3 vika Mg ben 2.3% by weight of Ti. 10 15 20 25 30 35 17 Polgmerisation 500 045 The prepared catalyst precursor was used for polymerization according to process A resp. C, written. The results are shown in Table 1. as above 500 045 IB . _9; ä = a: .._ = w..2_ ° = ° -3 ä ... få å? 3322. ä: m = omwwwæ fl o = o fl â .ä ä 3.55 än? w .ä .mä äà Fšäzswxv fi whmï fi .s ëoâtuuwï 2: 2 N ä .. then so ~ = - ~ S $ §3 ~ ¥ hm fi zaq. .2æmzw> - ~ .__ = 2%; å ä .sm-E .å ~ _ ° ~ _o ~ .H 0.0 @ _mß ~_.H_@_H m_ fi ~ ~ _> H. ° ON. Hmwos fi m N. ~ M æ_ ° H_H m_ @ m_.H ° _.ß m. ~ ~. ° m_ @ ~ H_.M ~ _fi ° ~ ° fi. ° E ° = F. ~ m ° _ ° H_ ° H_ ° m_ ° æ_ ~ m ~ .m @ ° .H @ _ °. ° ~., ~ M. @ H 0.0 ° ~ ß ~ .Ewa w ..u m_ ° @ _ ° O .. ~ _. æ. @ ~ ._H ~ m_ ° @ .Hm ~. @ m _.H cm fi ñ. ° = ° = N. ~ m __ ° @. ° æ_ ~, _ @ fi_ ° m ..- m_ ° m_m. @ ° .m ~ ° .mñ 50.0 _ oßæ fi .Ewa A. ~ “_ M ..u H. ° m.o ° _H, _ ° °. @. ___m ß_ ° ~ _ @ _ ° m_m ~ ~ __>,. ~ ° @ _m .Emm ~ .. ~ N .. H_ß ° _.m @ .w ~ ° .mH ß_ ~ v_ ° ... N ° .M ~., _ ° ° m @ _ -Emm H. ~ M cwm ß °. ° ° fi. ° m ~. ° @ m_ ° @ _ ° °. ~ n. \, ¥ = fi. ° _ \, CM. ° _ \ m; _- x ° \ mm O. =. ~ H ° @. °, _, x @ ~ @ : a: X ä; »IE Éëßšm fi šm fi å aæšzmm: Fa: ma: 35 :. ä .E åšmrßs. Ü fi åm-: wucumå .w .Éuxmuuxcwn xmmuæwmcowummwpmnw fi om: anwa 500 045 Iq .owhwfmmz ovcwcx: w: .Én .Ba ... unga ownmzwzumu w namngav m ~ @ ~ w> - ¥ ° ~. wu = - ~ Hw = - ~ p = - @ w = »um> ~ Mm» - fl hu m.- v fl. »Hmm-ma _.- kw * = ~ w = ° @ u- @ ~ w> _-- wn = ~ = mßwñ mvm .gg wxw fl æß fi ° m._ m @. ° m. ~ m -mä mø_ ° ~ m. ~ v .- = - ° H \ @ = - @ \ ~ = - ~ w>. = ~ ° m. = x ~. @ ~ ° m ~ = ¥ - @ s ... ~ _.._ ~ = ...__ s: ° = - ~ ° -m »- ~ W Mp. ~ ° -m ~ H- ~ = m-m @@ M x @ m ~ m «@ = ° w - @« - ~ ° @. ~ ë fi mpm fi

Claims (10)

SOU 045 10 15 20 25 30 35 20 A process for preparing a catalyst precursor for the polymerization of α-olefins, characterized by the steps a) contacting an inorganic oxide support with (i) a magnesium dialkoxide, (ii) a solvent for the magnesium dialkoxide, which includes a chlorinated alcohol as a main constituent ( iii) a titanium alkoxide b) chlorinating the support with a chlorinating agent; wherein steps (a) and (b) are performed in any order, and c) recovering the chlorinated product to give the catalyst precursor. 2. A process according to claim 1, characterized in that as solvent for the magnesium dialkoxide an additive amounting to not more than 2 mol / mol of magnesium dialkoxide of a chlorinated alcohol of the formula R "OH is used where R" is a chlorinated C2-C10-alkyl group, wherein the chlorinated alcohol is preferably 2,2,2-trichloroethanol. 3. A method according to claim 1 or 2, characterized in that the magnesium dialkoxide used has the formula Mg (OR ') 2 where R' represents the same or two different C2-C8-alkyl groups. 10 15 20 25 30 35 500 G45 21 4. A method according to any one of the preceding claims, characterized in that the titanium alkoxide used has the formula Ti (OR "') 4 wherein R"' represents the same or different C 2 -C 8 alkyl groups, and that the titanium alkoxide used is preferably is titanium tetrabutoxide. 5. A method according to any one of the preceding claims, characterized in that the support is chlorinated with a chlorinated aluminum alkyl compound, wherein each alkyl group has 1-20 carbon atoms, the chlorinated aluminum alkyl compound being preferably ethylaluminum dichloride (EADC) or diethylaluminum chloride (DEAC). 6. A method according to any one of the preceding claims, characterized in that the carrier is silica, which is activated by substantially eliminating its silanol groups, the activation treatment taking place either thermally at 600-110 ° C or chemically carried out by treatment. with a chlorinated aluminum alkyl compound. 7. A method of polymerizing α-olefins, characterized in that the polymerization is carried out in at least one step by means of a catalyst precursor prepared according to any one of claims 1 to 6; a cocatalyst, which is an organometallic compound of a Group I-III metal in the Periodic Table, preferably a trialkylaluminum compound; and optionally a molecular weight regulator, preferably hydrogen. 8. A method according to claim 7, characterized in that the polymerization is carried out in two steps, the first step being carried out as a polymerization in the liquid phase and the second step as a polymerization in the gas phase. 9. A method according to claim 7, characterized in that the polymerization is carried out in two steps, wherein both steps are carried out as gas phase polymerization. SCO 045 22 10. A method according to any one of claims 7 to 9, characterized in that an ethylene copolymer is prepared and that the comonomer is added in the second step. 10 15 20 25 30 35