SE500046C2 - Prodn. of catalyst precursor - for polymerisation of alpha-olefin(s), catalyst precursor being produced using an inorganic oxide carrier, pref. silica, in inert, liq. carbohydrate - Google Patents

Abstract

An inorganic oxide carrier is contacted with a magnesium dialkoxide and a solvent for magnesium dialkoxide, which includes a chlorinated alcohol. In a second stage, it is contacted with an aluminium alkyl cpd., and in a third stage with titanium tetrachloride. In a fourth stage, the product is recovered to provide the catalyst precursor. As solvent for magnesium dialkoxide, a chlorinated alcohol is used with the formula R''OH in which R'' is a chlorinated 2-10C alkyl group, and 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 carrier is treaded with an aluminium alkyl cpd. with the formula (R'''nALX3-n)m in which each R''' is the same or different and selected from hydrogen and alkyl groups with 1-20 carbon atoms, pref. 1-4, X is halogen, pref. chlorine, n is 1,1.5, 2 or 3 and m is 1 or 2.

Description

500 G46, 10 15 20 25 30 35 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 U.S. 4,302,565. silica is slurried in a hydrocarbon and treated in one first step with an aluminum alkyl, to block hydrogen the roxyl 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 im- impregnated silica is dried. In the third step, it is sludged impregnated the silica into a hydrocarbon after which the the croft precursor is pre-activated with an aluminum alkyl. It saw prepared catalyst precursor is then dried to 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 can have a negative impact on its activity and properties. Residual solvent also involves 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 nerad.

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 copolymers having a density above 940 kg / m ° and a melt flow (MFR2,16) of 1-30 g / 10 min and 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 3 ethylene (co) polymers, with varying densities and melting flows, can be referred to FI 906 427. as in the manufacture of is the narrow mole- In other contexts, films, bottles, cable jackets and tubes, cooling weight distribution obtained with Ziegler-Natta lysates with titanium as the active metal, however, a partly due to the poor flow properties and the poor processability. In these contexts is 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. However, they have other drawbacks. parts, by, for example, the molecular weight distribution being determined by the nature of the catalyst and cannot be significantly regulated by the reactor conditions. Furthermore, the chromium catalysts show poor hydrogen response, i.e. the molecular weight of the polymer can not is conveniently controlled by hydrogen addition to the reactor as is the case of Ziegler-Natta catalysts. Chromium catalysts also does not allow for precise regulation of comonomer the distribution in the preparation of copolymers.

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 Night catalysts and the disadvantages of chromium catalyst proposed to carry out the polymerization in several steps using Ziegler-Natta catalysts, and thereby keeping the polymerization conditions different in each stage or reactor. The polyethylene formed can then be obtained to constitute a mixture of at least two different qualities with different melt flow / molecular weight distribution, whereby molecular the cooling weight distribution of the mixture becomes wider than before the constituent components separately. Is molecular weight the distributions of the constituent components are sufficient separated, 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 as well as catalyst and cocatalyst additives are made 10 15 20 25 30 35 4 different in the different stages, which provides further opportunities.

An example of this technique is FI 86 867, 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 poly- merisation 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 pair pressure of 4-20 bar, the hydrogen concentration being is lower than in the first step. Further introduced any 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 catalyst properties to achieve optimal benefits.

In the production of relatively low molecular weight material in 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, because occurrence of hydrogen tends to lower the catalyst activity at polymerization of ethylene. In the second stage of polymerization the hydrogen content is low and further added in this step monomer. Both of these conditions help to provide one rapid increase in catalyst activity, which can thereby become undesirably high.

Thus, if the catalyst has poor hydrogen sensitivity, it will have too little 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 step (gas phase polymerization) and can result in 10 15 20 25 30 35 5 adequate heat transfer with risk of melting and / or sintering of the polymer. Consequently, it is desirable to have one catalyst with balanced properties, i.e. sufficient high activity in the presence of hydrogen, but not too high activity in the absence or at low levels of hydrogen and in presence of comonomer. In addition, the catalyst must be productive from the very beginning of the polymerization, because the residence time in the first polymerization step is pretty short. Furthermore, the catalyst must maintain its activity for a long time, because the residence time is long in the second (and possibly further 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 α-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 an organic technical oxide support, preferably silica, is contacted with a magnesium alkoxide, a chlorinated alcohol, an aluminum alkyl compound and with titanium tetrachloride.

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

An example of prior art is the US 5,093,443, which relates to the polymerization of α-olefins. veneer with a catalyst composition containing one chlorinated alcohol. According to this patent specification, a catalyst precursor by a solid support, such as 500 D46 10 15 20 25 30 35 EP 0 264 169, 6 silica, in a non-polar solvent, 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 such as hexane, con- soluble metal compound, such as titanium tetrachloride, which is soluble in the non-polar solvent. This reference differs from the present invention in several respects, for example by that a magnesium alkyl compound is used instead of one magnesium alkoxide.

US 4,954,470 and US 4,849,389 are further examples. prior art similar to that described above U.S. Patent.

As another example of prior art can be mentioned relating to a procedure for preparation of an ethylene-propylene copolymer rubber, and more specifically, a catalyst composition for this. Kata- the lysator is prepared from an inorganic oxide support, such as silica, a dihydrocarbylmagnesium compound (wherein the hydrocarbyl the byl groups are alkyl, cycloalkyl, aryl or aralkyl groups having 1 to 20 carbon atoms), a hydrocarbyloxy group holding compound based on silicon, carbon, phosphorus, boron or aluminum, a halogen-containing alcohol and a titanium compound, preferably titanium tetrachloride. Not in either in this case a magnesium alkoxide is used as in the present case current invention.

The preparation of the catalyst precursor according to the invention and its use in α-olefin polymerization will now be described in more detail, with a brief shall be provided by the ingredients used for the position of the precursor.

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 10 15 20 25 30 35 500 046 7 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 minium oxide, mixed oxides of silicon and aluminum, 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 130-1000 ° C. According to an form 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 600-100 ° 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 made using and 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 the silica thus pretreated is impregnated, described below, the hydrocarbon solvent may removed together with any excess hydroxyl group removal agents. The described measures can also fos- such as (TT CD 046 10 15 20 25 30 35 8 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 C 2 -C 8 alkyl groups, more preferably C2-C5 alkyl groups. As examples of particularly preferred magnesium dialkoxides may be mentioned magnesium dietoxide (i.e. R '= ethyl group), magnesium diisopropoxide (R'-iso- propyl 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 chlorinated alcohol as a solvent, it has been shown that to reduce the amount of polar solvent very significantly late. The molar ratio of polar solvent / magnesium dialkoxide can then be kept as low as below 2.0, whereby the amount of polar solvent includes both the chlorine alcohol and possibly further added polar solvent. The resulting mixture, containing magnesium dialkoxide and chlorinated alcohol (and possibly a further small amount of non-chlorinated co-solution agent) is then added to the silica. This can then either being in a dry state, one being substantially dry mixture is obtained, or, alternatively, be suspended in an inert hydrocarbon. This means that an impregnation step, with a slurry in a polar solvent, not is 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. 10 15 20 25 30 35 500 046 9 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 agent must be a chlorinated one alcohol. The one used as solvent in the invention, Chlorinated alcohol has the formula: R "OH wherein R "is a chlorinated C 2 -C 10 alkyl group, preferably one chlorinated C 2 -C 4 alkyl group, and most preferably a chlorinated ethyl group. It is especially preferred that it be chlorinated the alcohol is 2,2,2-trichloroethanol. Examples of other suitable chlorinated alcohols are 2-chloroethanol, 2,2-dichloro- ethanol, 2-chloropropanol, 2,2-dichloropropanol, 2,2,3-tri- chloropropanol, 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 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.

Finally, the carrier is contacted with the titanium-containing the compound of the present invention titanium tetrachloride.

As stated earlier, the carrier is treated with a aluminum alkyl compound. This is intended to react with hydroxyl groups, such as blocking silanol groups the silica support and react with excess alcohol. Alu- 500 046 10 15 20 25 30 35 10 the minium alkyl compound is usually added after the magnesium alkoxide and the chlorinated alcohol were added contact with the wearer, but can alternatively be added before.

The aluminum alkyl compound may be a trialkylallo- minium compound or of an aluminum alkyl compound, the alkyl groups are partially exchanged for halogen, The aluminum alkyl compounds can be represented by it such as chlorine. general formula ) (R '' 'nA1x3_n m where each R "'is the same or different and is selected from hydrogen and alkyl groups having 1-20 carbon atoms, X is a halogen, such as chlorine, bromine or iodine, n is 1, 1.5, 2 or 3, and m is 1 or 2 (the latter if n = 1.5). Preferably R "' a lower alkyl group having 1-4 carbon atoms, such as methyl, ethyl, propyl or butyl; X is preferably chlorine; and m is preferably 1. Particularly preferred aluminum alkyl compounds are triethylaluminum (TEA), diethylaluminum chloride (DEAC) and ethylaluminum dichloride (EADC).

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 currently preferred the most.

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 lysator precursor. In this treatment, gastric the magnesium alkoxide and the chlorinated alcohol first and 10 15 20 25 30 35 500 046 ll then the aluminum alkyl compound. As mentioned earlier, however, the aluminum alkyl compound may alternatively is added first, in connection with the pretreatment of the carrier for blocking its silanol groups. Then the wearer thus contacted with magnesium alkoxide, chlorinated alcohol and aluminum alkyl compound, titanium tetra- rachloride. The molar ratio of the added magneto the alumina and the added titanium tetrachloride can vary, but it is preferred to have a molar ratio Mg: Ti of about 1-3: 1, preferably about 2: 1. The amount chlorinated alcohol must be sufficient to together with other components dissolve the magnesium alkoxide, but not more than 2 mol / mol magnesium alkoxide. As mentioned earlier, a certain, smaller part of the chlorinated may the alcohol is exchanged for a co-solvent, consisting of for example THF or ethylene glycol. The resulting dry the mixture / slurry is stirred, preferably during heating, to a temperature of not more than about 100 ° C, drawn about 60 ° C or below. After the addition of titanium tetrachloride, the catalyst precursor is recovered by removal of slurry / solvent, as appropriate This is done by bubbling clean and dry nitrogen gas.

The resulting catalyst precursor is then ready to can be used together with cocatalyst for polymerization of α-olefins, preferably for the preparation 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 di- methylaluminum chloride (DMAC). Also dichloraluminum alkyls, as methylaluminum dichloride, may be used but is preferred not, as they provide lower activity. For suitable cocatalysts torer can be referred to John Boor Jr., “ziegler-Natta Catalysts and Polymerizations ", Academic Press, New York (1979), pp. 81-88. 500 046 10 15 20 25 30 35 12 Use of the one prepared according to the invention the catalyst precursor for d-olefin polymerization takes place by conventional polymerization processes under conventional conditions. The polymerization reaction carried out in at least one step as liquid phase polymerization 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. u To further illustrate the invention is given below some non-limiting embodiments.

Melt flows (MFR2, MFR5, MFR21) have been determined according to ISO 1133.

Example The polymerizations were carried out according to one 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 molar ratio of TEA: Ti 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. Reactive The mixture was stirred at a stirrer speed of 700 ° C rpm The temperature was raised to 90 ° C and the polymerization the tion was 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 10 15 20 25 30 35 500 046 13 pentane. The closed reactor was heated and at 85 ° C TEA was added to a TEA: Ti molar ratio of 60: 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 75 ° C 8.1 ml of 11.2% TEA, hydrogen from a container was added with a pressure of 25 bar, and ethylene to a total pressure of 11.5 bar in the reactor. After consuming 343 g of ethylene the pressure was reduced to 2 bar and the reactor was pressurized with nitrogen. hydrogen gas was filled into the hydrogen gas container to a pressure of 0.5 bar hydrogen, the container for the comonomer was charged with 120 ml of 1-hexene. Hydrogen and comonomer was transported into the reactor using ethylene. The total pressure in the reactor was 10.5 bar. Food consumption the second step was 346 g. 500 046 10 15 20 25 30 35 14 Example 1 Preparation of catalyst precursor 3.118 g of silica of quality 955 W 20, which was activated at 600 ° C, and 0.714 g (2.0 mmol / g silica) of magnesium diethoxide was slurried under nitrogen at room temperature for 15 h ml of dry n-pentane in a 150 ml flask equipped with a septum. Then 1.397 g (3.0 mmol / g silica) was added trichloroethanol to the slurry. This was stirred at 45 ° C for 3 hours and then 0.192 g (0.54 mmol / g) was added silica) TEA. The slurry was then further stirred 10 min at 45 ° C, then finally 0.592 g (1.0 mmol / g silica) TiCl 4 was added. by nitrogen gas bubbling with the catalyst precursor was obtained as an orange-brown powder. Its composition was 0.76 wt% Al, 23.9 wt% Cl, 2.52 wt% Mg and 2.5 weight% Ti.

Pole merization was performed according to method B above.

The results are shown in Table 1.

Example 2 Preparation of catalyst precursor 8.39 g of silica of quality 955 W 20, which was activated at 600 ° C, and 2.39 g (2.0 mmol / g silica) of magnesium propoxide was slurried under nitrogen in 25 ml of dry n-pentane The solvent was then evaporated at room temperature in a 150 ml flask equipped with a septum. Then 3.72 g (3.0 mmol / g silica) was added _trichloroethanol to the slurry. This was stirred for 3 hours at 40 ° C and then 2.56 g (0.60) was added mmol / g silica) 25% EADC. The slurry was stirred during another 45 minutes at 40 ° C, then finally 1.592 g (1.0 mmol / g silica) TiCl 4 was added. The solvent was then removed by nitrogen gas bubbling the catalyst precursor was obtained as a yellow-gray powder.

The composition of the catalyst precursor was: 0.81% by weight of Al; 25.1% by weight of Cl; 2.4 wt% Mg and 2.4 wt% Ti.

Pole merization was carried out according to procedure A resp. C above. The results are shown in Table 1. 10 15 20 25 30 35 500 G46 15 Example 3 Preparation of catalyst precursor 8.66 g of silica of quality 955 W 20, which was activated at 600 ° C, and 2.47 g (2.0 mmol / g silica) of magnesium dipropoxide was suspended under nitrogen in 25 ml of dry n-pentane at room temperature. temperature in a 150 ml flask equipped with a septum. Then 3.84 g (3.0 mmol / g silica) of tri- chloroethanol to the slurry. This was stirred for 4 hours at 40 ° C and then 6.6 g (1.5 mmol / g silica) were added 25% EADC. The slurry was stirred for another 120 minutes at 40 ° C, then finally 1.64 g (1.0 mmol / g silica) TiCl 4 was added. The catalyst precursor was then dried by bubbling nitrogen gas, leaving a yellow-gray powder was obtained. Its composition was: 1.9% by weight of Al; 26.7% by weight Cl; 2.3 wt% Mg and 2.3 wt% Ti.

Polzmerization was carried out according to procedures A and B. above. The results are shown in Table 1.

Example 4 Preparation of catalyst precursor 25 g of silica 955 W 20, activated at 600 ° C, and 5.72 g (2.0 mmol / g silica) of magnesium diethoxide was slurried under nitrogen in 75 ml of dry heptane at room temperature in a 2 1 reactor. Then 13.1 g (3.5 mmol / g silica) were added trichloroethanol. The slurry was stirred for 5 hours at 97 ° C.

The slurry was dried and a powder was obtained. The dry powder was slurried in the pentane. Then 13.8 g (0.54) was added mmol / g silica) 11.2% TEA. The slurry was stirred during another 1 hour at 36 ° C, then finally 4.74 g (1.0 mmol / g silica) TiCl 4 was added. The solvent is removed was then bubbled through with nitrogen gas, whereby the lysator precursor was obtained as a gray powder. Its composition was 0.73% by weight Al; 25.7% by weight of Cl; 2.4% by weight Mg and 2.4 v1kc% Ti.

Polymerization was performed according to Method A above.

The result is reported in Table 1. ' 500 046. 16 Example 5 A catalyst precursor prepared according to US 4 302,565, and which had the composition: 2.3% by weight of Al; 7.5 weight% Cl; 1.4 wt% Mg and 0.95 wt% Ti, were used for Copolymerization according to method B above. The result is shown in Table 1. 10 15 20 25 30 35 500 046 / 7 .m.nu uu = muwmnm @ »uu: mmm: vw cm øcomuuuuumb Qhaywn = ° H-uH - H ° @. ~ M v fi> M nuø fi.- = W ~ «~ = - ~ ° -u ~ H- ~ x -m fi> mm =. ~ = ~ @ ~ M> .- = vhmms »v> ~ hmm-mha .øm H. ° @ _ ° @. ~ @. @ ~. @ M «_> ~ m. ° @ _m ~ ° _m_ ~ @ .H ~ @ _ ° QFQH .. ~ m _ ~ u fi. m. ~ m H. ° m_ ° «.m ~ _ @ @. ° m ~. @ ~ ~. °“ N Qm ° .m ° _ ~ °° m ~ .. ~ m m .- m. ° m. ° «.H @. ~ ~. ° m>. @ m m_ @ @ _ ° ~ m. ° ~ ° _m °° _ ° 00.» . °. ° = v. ~ M @ _ ~ M_E @ _- @_m_ @ .æm ~ _ ~ m. ° FN _. ~ H @ .H _ @. ° ° fifi ~. ° = ° = M. ~ M M .. 0 .. @_m_ ° .vH °. @ M @. ~ ~ _ ° @_> ~ ° ._ ~ _ ° @ °. ° °°° H -@°.fi m ~ .- ~ .fi @_m ..mH @ _ ° _ @ _ @@ _. @ ~. ° ñ_ ° ~ ~. @ ~ ~ _ ~ ß_ ° Qmß fi. °. ° = ~. ~ u ~ _- °. ~ _ 5 .. @__ Qmmw .gwm H .- ä: .ä s ... s ... m ... a ... 2 3 s. s: a. a: .i å ... ... ax å .. m .så små; .. = Nwm. ~>, “~ X«> _ u- ~ = - ¥ @ m -m = \ H ~,. = _- ~ = m ~. = ~ =. = - ~ Q ~ => ~ @ ~ h. ~ °. ~ m-- ~. .houxmøuxcwn w xmwuæwunowumm fi homw fl om. ~ fifi onmh

Claims (10)

500 046 10 15 20 25 30 35 18 A process for preparing a catalyst precursor for the polymerization of α-olefins, characterized by the steps of contacting an inorganic oxide support with a) a magnesium dialkoxide and a solvent for the magnesium dialkoxide, which includes a chlorinated alcohol, b) an aluminum alkyl compound; wherein steps (a) and (b) are performed in any order c) titanium tetrachloride, and d) the product is recovered to give the catalyst precursor. 2. A process according to claim 1, characterized in that a chlorinated alcohol of the formula R "OH is used as solvent for the magnesium dialk, where R" is a chlorinated C2-C10 alkyl group, the chlorinated alcohol preferably being 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' 4. A method according to any one of the preceding claims, characterized in that the carrier to be treated represents the same or two different C2-C8-alkyl groups. with an aluminum alkyl compound of the formula (R "'nAlX3-n) m wherein each R"' is the same or different and is selected from hydrogen and alkyl groups having 1-20 carbon atoms, preferably 1-4 carbon atoms, X is halogen, preferably chlorine, n is 1, 1.5, 2 or 3, and m is 1 or 2. 5. A method according to claim 4, characterized in that the support is treated with a trialkylaluminum compound, preferably triethylaluminum. 6. A method according to claim 4, characterized in that the carrier is treated with a chlorinated aluminum-alkyl compound, preferably diethylaluminum chloride or ethylaluminum dichloride. 7. A process for the polymerization of 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, Group I-III metal of 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 liquid phase polymerization and the second step as a gas phase polymerization. 9. A method according to claim 7, characterized in that the polymerization is carried out in two steps, both steps being carried out as gas phase polymerization. 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 fed in the second step. which consists of an organometallic compound of a