DE2352154C3 - Process for the low pressure polymerization of ethylene - Google Patents

Description

a) an aluminum trialkyl, alkyl aluminum hydride or Ai ^ ylaluiniaiamhalogenid, their alkyl radicals are straight or branched and contain 1 to 20 carbon atoms, or one Reaction product of the aluminum trialkyls mentioned or alkyl aluminum hydrides with isoprene and

b) a solid catalyst complex, which by reaction of a halide, oxyhalide or Alkoxyhalide one of the metals titanium, vanadium, zirconium or chromium with a porous alumina or a porous complex oxide of the formula

as a carrier whose internal porosity is above 0.3 cmVg and whose specific surface area is above 100m ² / g, which can optionally be halogenated and on which a magnesium compound is fixed

as well as in the presence of hydrogen as a molecular weight regulator,

characterized in that polymerisation is carried out in the presence of catalysts, during the production of which the magnesium compound is a magnesium halide, a hydrated magnesium chloride or a magnesium phenoxide br.w. alkoxide, the organic radicals of which have 1 to 6 carbon atoms, was used in such an amount that the amount of the magnesium compound deposited on the porous support was between 1 · 10 'and 5 · iO ^! mg-Alomen magnesium per m ^{2 of} the specific surface area of the porous support.

2. The method according to claim 1, characterized in that the magnesium compound on the porous support in the form of a mixture with an oxygen-containing, organic titanium compound general formula

[TiO ₁ (OR) ₁ ] ,,,,

where R is an organic radical with I to 20 carbon atoms, γ and y are any numbers from χ > 0 and y> 0 that take the valency of titanium into account, and / ;; tine is an integer. has been deposited.

JO

4-,

6i nhimoxiden (see laid out documents of the Belgian patent 7 73 227) to bind.

The catalysts obtained in this way are very active when compared with those at which the transition metal compound is used as such. They lead to polymers, which are characterized by a broad molecular weight distribution and are free from long-chain branches which makes them particularly suitable for further processing by blow molding.

However, these previously known catalysts have a significant disadvantage. You will namely mostly used in polymerization processes of olefins which, in the presence of a molecular weight regulator, which is almost exclusively hydrogen. It was also found that these systems catalyze the hydrogenation of olefins. A non-negligible part of that to be polymerized Olefins are therefore converted into the corresponding, saturated hydrocarbon, whereby the economic viability of the process is jeopardized. On the other hand, these catalysts produce polymers with a very high average molecular weight. To reduce this average molecular weight is one therefore forced to increase the hydrogen concentration in the polymerization medium and / or the Carry out polymerization at a higher temperature. However, these two measures have the harmful one The result is that the degree of hydrogenation of the olefin to be polymerized is further increased.

In the process of DE-OS 2109 273, ethylene is polymerized in the presence of hydrogen and catalysts from organoaluminum compounds and a catalyst component which has been produced from porous aluminum oxide, on which ethylmagnesium chloride has been fixed, and titanium tetrachloride. Polymers with a narrow molecular weight distribution and a relatively low average molecular weight are obtained. In the process of DE-AS 17 70 726 one obtains with the Äthylenpolymeris; <lion i- .. presence of hydrogen and catalysts from an organoaluminum compound and a solid catalyst _{component based on aluminum oxide Mg (OH) 2} and TiCU also with polymers very narrow molecular weight distribution, which are suitable for injection molding processing. If the polymerization of hydrogen-containing ethylene mixtures according to DF.-OS 21 37 872 is carried out in the presence of catalysts made from organoaluminum compounds and a catalyst component made from a magnesium chloride-aluminum oxide mixture and JTiCIi AICIi, polymers with a relatively low molecular weight suitable for injection molding are also formed.

The invention now relates to a process for the low-pressure polymerization of ethylene or for the low-pressure copolymerization of ethylene and olefins having 1 to 6 carbon atoms in the presence of catalysts

a) an aluminum trialkyl. Aluminum hydride cider Aikylaluminiumhalogenid, whose alkylresle straight-chain or are branched and contain 1 to 20 carbon atoms, or a reaction product of the aluminum alkyls or alkylaluminum hydrides mentioned with isoprene and

b) a solid catalyst complex, which is produced by the reaction of a halide. Oxyhalide or

Alkoxy halide one of the metals titanium, vanadium, Zirconium or chromium with a porous alumina or a porous complex Oxide of the formula

or

MgO · AhOj ₁ SiO ₃ - AJiO ₁
MgO • SiO ₂ • Al ₃ Oj

as a carrier whose internal porosity is above 0.3 cmVg and whose specific surface area is above 100mVg, which can optionally be halogenated and on which a magnesium compound is fixed
as well as in the presence of hydrogen as a molecular weight regulator,

in which the disadvantages of the known processes mentioned above are avoided and polymers with a broad molecular weight distribution and with a relatively high average molecular weight are obtained, which are suitable for extrusion and blow molding when polymerizing in the presence of catalysts in their production as a magnesium compound a magnesium halide, a hydrated magnesium chloride or a magnesium phenoxide or alkoxide, whose organic radicals having from 1 to 6 carbon atoms, was used in an amount such that the amount of the deposited on the porous support of magnesium compound is between 1 × 10 ^"J and 5 x 10 " ^J mg-atoms of magnesium per nv ^{2 of} the specific surface area of the porous support.

The internal porosity of the catalysts used to produce the catalysts used in accordance with the invention Carrier oxides, measured according to the procedure known under the designation BET method - see S. Brunauer, P. Emmelt and E. T e 11 e r in J. Am. Chem. Soc, 60: 309-319 (1938) above 03 cmVg and preferably above 0.7 cm Vg. Excellent results are obtained with porous oxides whose internal porosity is above 1 cm Vg.

The porous oxides used have a specific surface area above 100 m ² / g, more often in the range of 200 to 400 mVg. These specific surface areas are measured by the BET method described above, using the standardized method described in British Standards BS 4359, Part 1 (1969).

The grain size of the porous oxides used does not affect the productivity of the catalyst. the end For reasons of easier handling, however, the use of particles is preferred, their medium Diameter is between 1 and 500 microns and preferably between 40 and 200 microns. the The morphology of the polymer and its flowability are, however, improved when using porous oxides regular particle shape and narrow grain size distribution. Excellent results will be obtained with porous oxides, the mean diameter of the particles of which is close to 100 microns and whose diameter distribution is narrow.

The exact chemical structure and the method of manufacture of the porous oxides used are not critical provided that they conform to the above.

The aluminum oxides can be produced by all known methods, examples are:

- by pyrolysis of aluminum oxide hydnites, aluminum hydroxides or aluminum salts at elevated temperature;

- by precipitation of soluble, dissolved in water Aluminum salts such as nitrate and chloride in the presence of an alkaline compound such as Ammonia and pyrolysis of the gel obtained in this way.

Particularly suitable aluminum oxides are the active

lu fourth aluminum oxides obtained by pyrolysis of Aluminum oxide hydrates were produced at elevated temperature (see laid-out documents of Belgian patent 7 68 271). Excellent results are obtained with activated aluminum oxides,

ι? having an internal porosity greater than 1 cmVg and were prepared from the a-monohydrate by heating at 700-800 ⁰ C for 4 to 24 hours.

Suitable complex oxides include sillimanite Al ₂ O ₃ · SiO ₂ and spinel MgO _{· Ai 2} Oj.

The synthetic complexes O '.' ^ E can after known methods are produced, for example, results in the working technique referred to as mixed precipitation always satisfactory results. It consists in the soluble salts of aluminum and the dissolve other metals in solution in water in such quantities that the desired ratio for the complex oxide is achieved in the solution. The nitrates are usually used as soluble salts,

jo chlorides and acetates. Then you go to the Dissolving progressively an alkaline substance such as ammonia or sodium carbonate in aqueous solution added. In this way, the formation of a solid precipitate is brought about, which after the pyro-

j5 lysis, finally, those which can be used according to the invention complex oxides.

Excellent results are obtained with complex oxides of aluminum and magnesium with a internal porosity above 1 cm Vg obtained, which correspond to the general formula MgO · A ^ Oj.

All of the above-described porous oxides can be subjected to a halogenation treatment before the deposition of the magnesium halogen compound under the individual in the laid down documents of the

4j Belgian patent 7 73 227. This halogenation treatment improves the productivity of the catalysts produced from the porous oxides. It consists in that porous aluminum oxides of the action of a halogen

-) 0 nating agent to submit. This latter is preferably a fluorinating agent. It is preferred to choose it from solid and volatile with no residue Products ^ replaceable compounds, such as B. Ammnii'imfluorid. This treatment can be done like this that the halogenated aluminum oxides obtained are egg aluminum oxide complexes Have an atomic ratio of halogen / aluminum between 0.01 and 1. The best results are obtained when this ratio / is between 0.06 and 0.30 and in particular between 0.10 and 0.15.

The porous aluminum oxides can advantageously be subjected to a thermal treatment before they are brought into contact with the magnesium compound, in particular if their production has not been completed by pyrolysis. Such treatment is preferably carried out at a temperature between 100 and 1000 ⁰ C, between 300 and 800 ° C. In the case of porous oxides,

which have been subjected to a halogenation treatment, such a thermal treatment with the halogenation treatment or follow it. It is therefore carried out under such conditions that porous oxides are obtained obtained, which have the above-specified atomic ratio halogen / aluminum. The pressure under which such treatment is carried out and the atmosphere in which one works are not critical. However, for the sake of simplicity, it is preferred under atmospheric pressure and in an inert atmosphere to work. The duration of the thermal treatment is also not critical and is in the generally between 1 and 24 hours.

The above-described porous aluminas must be treated with the magnesium compound in this way that a deposit of this compound is produced on the surface of the porous oxide.

AIc \ AatTnaciitma \\ tr \ viAt * cinH 7 R. / iac \ At * th \ ililt / iac

Magnesium compound deposited on the porous oxide:

- in the form of solids, e.g. B. in suspension in one inert diluents;

- in the form of steam or gas;

- in a liquid medium, be it in the form of a solution in Water or ih an organic solvent which dissolves the magnesium compound in the Is able, be it in the presence of an oxygen-containing, organic compound (M), as it is in the the following is defined in more detail.

The temperature at which the magnesium compound is deposited on the porous aluminum oxide is not critical. Preference is given to working at a temperature below the decomposition temperature of the magnesium compound. In the case of the use of the magnesium compound in the form of pinpr I r \ ciincr arHoitit man mpiclfinc in Af * r Mäh «» Aar

Ethylate, and the isopropylate usable.

Among the magnesium halides the following can be mentioned:

Commercially available magnesium dihalides, which are commonly referred to as "anhydrous", but which are actually hydrated dihalides containing one mole or less of water per molecule of the dihalide;
"Anhydrous, commercially available" magnesium dichlorides are a typical example of such compounds;

- hydrated magnesium dihalides, which contain more than one molecule of water per molecule of the dihalide included, such as B.

MgCl ₂ · 6H ₂ O, MgCl ₂ · 4 H ₂ O and MgCl ₂ · 2 H ₂ O.

Of these, the dihalides are preferred, with the best results using the hydrated magnesium dichlorides can be obtained. The use of two or more different compounds from the The compounds given above are also within the scope of the invention.

The amount of magnesium compound to be deposited on the porous alumina is an essential feature of the invention. Expressed in the weight of the magnesium, based on the surface of the porous oxide, it must be between 1 - 10 ^-3 and 5 · 10 ^-3 mg-atoms of this metal per m ² specific surface (BET) of the porous oxide.

The results are optimal within the limits given above. However, it was observed that the optimum amount of the magnesium compound varies slightly depending on the kind of the compound

The best results are obtained with porous oxides, which have a specific surface area between 200 and 400 m ² / g and on which have been deposited:

- 1 x 10 ^{-3 to} 2.5 x 10 ^-3 mg-atoms Mg / m ^{2 of} the specific surface area of a magnesium phenoxide or alkoxide

- 2 · 10 ~ ³ to 4 - 10- ³ mg-AtomsMg / m ² on the specific surface of a magnesium halide.

The deposition of the magnesium compound on the surface aes porous alumina can be carried out by any known method. In particular, the required amount of temperature, which corresponds to the maximum solubility of the magnesium compound. The pressure is also not essential; generally one works in the vicinity of atmospheric pressure.

It is preferred to use the magnesium compound in a liquid medium. It has surprisingly been found that when the magnesium compound is deposited on the porous oxide according to this method, part of this compound always remains chemically irreversibly bound to the porous aluminum oxide. This bond is practically quantitative if the amount of magnesium compound used, expressed as the weight of this metal, is below 5 · 10 ^-3 mg-atom Mg / m ² on the specific surface of the porous oxide.

The magnesium compound can be used in a liquid medium by several methods, further details are described below.

A first mode of operation consists in taking the magnesium compound in the form of a solution in a solvent to use the water or an organic diluent capable of dissolving the magnesium compound is. All diluents customarily used in organic chemistry can be used will. However, preference is given to using the alkanes and cycloalkanes whose molecules are 4 to 20 Contains carbon atoms, e.g. B. isobutane, n-pentane, pentamethylpentane, η-hexane, n-heptane, cyclohexane, Methylcyclohexane and the dodecanes. It is also possible to use alcohols whose molecule is 1 to 12 Has carbon atoms per hydroxyl radical, * like methanol, ethanol, butanol, decanol and cyclohexanol, likewise mixtures of the aforementioned alcohols, alkanes and cycloalkanes.

It is also possible to use solvents which have a strong ability to form complexes, such as B. tetrahydrofuran. The magnesium dihalides are used in the form of an aqueous solution preferred

A particularly simple way of causing the deposition of the magnesium compound on the porous alumina according to this procedure consists in the oxide with the help of a volume to treat the solution so that the mixture retains the properties of a powder, this Volume contains an amount of magnesium compound, which is at least equal to the amount that can be chemically fixed or bonded to the oxide that of the

Contact preferably at ambient temperature and with stirring for a period of time which generally varies between about 1 minute and 1 hour. The possibly Any excess can be removed with the aid of a solvent for the magnesium compound to be removed. As such a solvent is preferably a Solution selected that the person to carry out four impregnation or impregnation of the porous aluminum oxide used solvent is identical.

After the magnesium compound has been deposited on the porous alumina by this procedure the solid thus obtained is generally subjected to an activation treatment, whereby the Removal of the solvent is easily possible. Such activation treatment is general essential if the solvent used was water

Preferably it is used at a temperature below the decomposition temperature of the magnesium compound carried out, however, this condition is by no means essential, and decomposition of the magnesium compound is harmless for the catalyst properties as long as the magnesium content of the porous Oxides remains within the limits given above. The other operating conditions of the activation treatments are selected depending on the type of solvent used, and they are generally the same in which the thermal treatment described above is carried out.

For certain insoluble in water or one of the above-mentioned organic diluents Magnesium compounds can also be used in a liquid medium according to a second mode of operation use, where they with an oxygen-containing, organic compound (M) of a metal of Groups Ia. lib. IHb, IVa. IVb. Va, Via, Vila and VIII des Periodic table, optionally in the presence of a diluent, are mixed. Under this Definition of an oxygen-containing, organic compound (M) are to be understood as meaning all compounds in which an organic residue is bound to the metal via oxygen. Connections that also binds Contain metal-oxygen as well as condensed compounds, which bond sequences metal-oxygen-metal can also be used provided they also have at least one bond sequence Have metal-oxygen-organic radical per molecule.

The organic radicals bonded to the metal via the oxygen can be any radicals. They are preferably selected from the same radicals that were used in the composition of the oxygen-containing, organic magnesium compounds are possible, and preferably from hydrocarbon residues and particularly preferably from straight-chain or branched alkyl radicals, cycloalkyl radicals, arylalkyl radicals, Aryl radicals and alkylaryl radicals.

As metals the aforementioned. Groups can e.g. B. are mentioned: lithium, sodium, potassium, zinc, Boron, aluminum, silicon, tin, titanium, zirconium, vanadium, chromium, manganese, iron, cobalt and nickel, however, the use of oxygen-containing organic compounds of aluminum, silicon, Titanium, zirconium, vanadium and chromium are preferred The best results are obtained with oxygenated, organic titanium compounds.

These oxygen-containing organic compounds (M) can be represented by the general formula

[MeO ₁ (OR) Jm

are reproduced, in which (Me) is a metal from the above-mentioned groups, R is an organic radical as defined above, χ and y any numbers from a '> 0 and y> 0, which are compatible with the valence of the metal (Me), and m are an integer. The use of oxygen-containing organic compounds (M). in which xO <χ <1 and m \ <n) <6 is preferred. As oxygen-containing organic compounds (M), which are intended to be brought into contact with the magnesium compound, can

be called lä:

- alkoxides such as Li (OiC ₃ H ₇ ), AI (OiC ₃ H ₇ ) J,
B (OiC ₃ H ₇ J ₃ , Si (OC ₂ H ₅ J _4. Ti (OiC ₃ H ₇ J ₄ ,
Ti (OiC ₄ Hq) ₄ , V (OiC ₃ H ₇ J ₄ and Zr (OiC ₃ H ₇ J ₄ ;

- phenoxides such as Ti (OC ₆ Hs) ₄ ;

- Oxyalkoxides such as VO (OiC ₃ H ₇ ) ₃ ;

- condensed alkoxides such as TIzO (OiC ₃ H ₇ Je;

- enolates such as titanium acetylacetonate.

The use of oxygenated, organic compounds (M), which are several different organic Revealing remains is also possible. The same applies to the use of several different, oxygen-containing organic compounds of one and the same metal and the use of several oxygen-containing, organic compounds of different metals.

The working conditions for the mixture of the magnesium compound with the oxygenated, orgarüschen Connection (M) must depend on the physical state of each of these connections are selected such that a liquid mixture or a solution is formed, whose Magnesium concentration is sufficient to produce the desired amount of magnesium on the surface of the porous To deposit aluminum oxide. When working in the absence of a thinner, the temperature and pressure conditions selected such that at least one of the compounds and preferably

the oxygen-containing organic compound (M) is liquid is. Often such a compound, which is kept in the liquid state, can be the magnesium compound dissolve. A second oxygen-containing organic compound (M) can also be used.

which is liquid and able to dissolve the magnesium compound.

However, it can happen that the oxygen-containing, Organic compound (M) decomposes by heating that the mixture of this compound and the Magnesium compound becomes solid by cooling or that none of these compounds are in the liquid State can set. In this case, however, the magnesium compound can be deposited on accomplish the porous oxide in liquid medium using a diluent, which is preferably selected from the aforementioned organic diluents and for at least partial dissolution of the oxygen-containing, organic compound (M) or the product of its mixture with the magnesium compound in the Location is.

The use of such a diluent for this purpose is the preferred embodiment

the use of the magnesium compound according to this second procedure. It should be pointed out that this second procedure, and in particular the variant described above, can be applied quite generally to the majority of water-soluble magnesium compounds and in particular to the dihalides of this metal. It has the essential advantage that in this case the level of activation mentioned in the description of the first mode of operation is suppressed. When producing the deposition of the magnesium compound on the surface of the porous aluminum oxide according to this second embodiment or mode of operation, the amount of oxygen-containing organic compound (M), which is liquid or dissolved in the diluent, must at least ensure the dissolution of the required amount Magnesium compound is sufficient. In general, the respective amounts of these compounds to be used are such that the atomic ratio · iiii between the Meiül! (ivie) the acidity, in organic compounds, and of magnesium varies between 0.5 and 100 at-g / at-g and preferably between 0.5 and 2 at-g / at-g. When using the variant of this second procedure, which consists in adding a diluent to the oxygen-containing, organic compound (M) or to the mixture of this compound with the magnesium compound, it is preferred if the total concentration of the dissolved compound or compounds is above 5% by weight and preferably above 20% by weight, based on the diluent. The other conditions for the preparation of the solution or the liquid mixture are not critical. For the sake of simplicity, it is preferred to operate between 20 and 300 ° C. and preferably between 50 and 200 ° C. and at about atmospheric pressure Stir homogenized.

A very simple way to deposit the magnesium compound on the porous aluminum -to To get oxide according to this second embodiment, is first a solution of the

Cipmicrhp? ur \ n MiicrnpciiirrvvprHinrliincT nnrl caiiprQtnff-

OO

containing organic compound (M) in the diluent and the porous oxide with a fixed volume of this solution according to that mentioned in the description of the first embodiment Method to treat. You can also convert the porous oxide in this solution into suspension, the Maintaining contact between the oxide and the solution under the conditions mentioned above, the Excess of the solution z. B. by filtration or decanting and remove the solid thus obtained win, which is then used as such in the continuation of the preparation of the catalyst complexes (b) will.

As one of the essential characteristics of the porous aluminum oxides, soft for the production of the catalyst complexes (b) used in their surface magnesium content, must be chemical Reactions, the mechanism of which is not yet known, are ignored, soft between the Magnesium compound and the oxygen-containing organic compound (M) in the production of the molten mixture or the solution, with the help of which the deposition of the magnesium compound occurs on the porous oxide.

The last step in the preparation of the solid catalyst complexes (b) consists in the porous alumina, on which the magnesium compound is deposited - velche in the following as "solid" is referred to -, with one of the mentioned compounds of titanium, zirconium, vanadium or chromium to implement. When the solid is produced with the help of an oxygen-containing organic compound (M) whose metal (Me) is one of these metals, preferably becomes a transition metal compound selected whose metal is identical to the metal (Me). The best results will be with titanium compounds obtain.

When using halogenated compounds, brominated and chlorinated compounds are used Connections like

TiCU ₁ TiBr ₄ , VCl ₄ , VOCl ₃ . VOBr ₃ .
CrO ₂ CI ₂ , Ti (OC ₂ H ₅ J ₃ CI, Ti (OiC ₃ H ₇ ) 3CI,
Ti (OC ₂ Hs) ₂ CI ₂₁ Ti (OiC ₃ H ₇ ) Cl ₃ and ZrOCl ₂

preferred. If compounds containing alkoxide radicals are used, these are preferably selected from compounds whose straight-chain or branched alkoxide radicals each have 1 to 20 carbon atoms and particularly preferably 1 to 10 carbon atoms each, such as Ti (OiC ₃ H7) ₃ CI.

The use of several different transition metal compounds is also possible.

Preferably, the transition metal compound is selected so that it is in the form of steam or Gas, optionally diluted with an inert gas, used in liquid form or in the form of a solution will. The solvents used are generally those customarily used in low-pressure polymerization diluents used by olefins. However, it is preferred to direct the solid with a large Bringing the amount of pure, liquid transition metal compound into contact, z. B. by simply transferring it into suspension. The reaction can also be brought about by the solid with the transition metal compound, if this is L'Issig under the reaction conditions, wäirht nrlpr nnrh inrlpm rfpr Fpuctnff with aiifpinnnrler the following, fresh batches of the transition metal compound in a continuous extraction apparatus of the Soxhlet or Kumayawa type in Contact is brought. This latter working technique is particularly recommended when the Solid according to the preferred variant of the second embodiment or mode of operation described above has been made.

The temperature at which the reaction is carried out is not critical. Generally one works between 0 and 300 ° C. When working at atmospheric Pressure is the temperature between ambient temperature and normal boiling temperature of the transition metal compound selected. Therefore, preferably between 20 and 140 ° C is used.

Contact with the transition metal compound is maintained for a sufficient period of time thus a chemical bond or fixation of the transition metal compound on the Solid takes place. In general, such bonding or fixation is achieved after 30 minutes to 1 hour achieved

After the reaction, the catalyst complex obtained can (b) Washed with the same transition metal compound that was used for the reaction

was, in general he will then with help washed with an inert hydrocarbon solvent, such as B. isobutane, n-pentane, η-hexane, cyclonetane and the dodecanes to avoid the chemically on the Remove carrier-fixed excess of transition metal compound. When performing the elemental analysis of the catalyst complex (b) treated in this way, a transition metal content is measured which is in the is generally above 10 g / kg and very often above 15 g / kg as well as a magnesium content, which is equal to or slightly below the magnesium content of the solid used to produce the Catalyst complex (b) was used.

The catalytic systems according to the invention include remote »e ^! ne organometallic compound of a metal from groups Ia, Ha, lib, IUb and IVb of the periodic table such as organometallic compounds of lithium, magnesium, zinc, aluminum or tin. The best results are obtained with organoaluminum compounds.

As aluminum trialkyls whose alkyl chains are 1 to 20 Contain carbon atoms and are straight-chain or branched, Tnmethylaluminium, Triäthyl- • luminiurn, Triisobutyl aluminum, tri-n-butyl aluminum and tri-n-decyl aluminum can be used. the Use of trialkylaluminum compounds whose alkyl chains contain 1 to 10 carbon atoms and straight or branched chain is preferred.

It is also possible to use alkylaluminum hydrides whose alkyl radicals also have 1 to 20 carbon atoms such as diisobutylaluminium hydride. Also suitable are aluminum alkyl halides in which the Alkyl radicals also contain 1 to 20 carbon atoms, such as ethyl aluminum sesquichloride, diethyl aluminum chloride and diisobutyl aluminum chloride.

Finally, one can also use organoaluminum compounds obtained by that trialkylaluminum compounds or dialkylaluminum hydrides whose radicals have 1 to 20 carbon atoms have been allowed to react with isoprene ("isoprenylaluminum compounds").

As comonomers are propylene, butene- (l), 4-methyl-

A-. / t \ III / i \ l UI

fvllH.ll ^ i; UIIU l lvAt.ll ^ t / Ul UUVItt / UI.

The process according to the invention is particularly good for the production of ethylene homopolymers and copolymers which contain at least 90 mol% and preferably 95 mol% ethylene are suitable.

The polymerization can be carried out in solution or in suspension by any known technique carried out in a hydrocarbon solvent or diluent or in the gas phase will. In the solution or in suspension procedures, solvents or are used Diluents which are analogous to those used for washing the catalyst complex (b): these are preferably alkanes or cycloalkanes such as butane, pentane, hexane, heptane, cyclohexane, methylcyclohexane or their mixtures. You can also do the polymerization in the monomer or one of the Monomers, which is kept in the liquid state, perform.

The polymerization pressure is generally between atmospheric pressure and 100 kg / cm ² , preferably 50 kg / cm ² . The temperature is generally selected between 20 and 200 ⁰ C and preferably between 60 and 120 ⁰ C. The polymerization can be carried out continuously or batchwise.

The organoaluminum compound (a) and the catalyst complex (b) can be added separately to the polymerization medium. They can also be brought into contact at a temperature between -40 and 80 ^° C. before being introduced into the polymerization reaction vessel for a period of time which lasts up to 2 hours. Furthermore, they can be brought into contact with one another in several stages, or part of the organoaluminum compound (a) can be added before the reaction or several different organoaluminum compounds (a) can be added.

The total amount of the organoaluminum compound (a) used is not critical. It is generally between 0.02 and 50 mmol / dm ³ of solvent, diluent or volume of the reaction vessel, and preferably between 0.2 and 5 mmol / dm ³ . The amount of the catalyst complex (b) used is determined as a function of the transition metal content of the complex. In general, it is selected such that the concentration is between 0.001 and 2.5 and preferably between 0.01 and 0.25 mat-g of the metal per dm ^{3 of} the solvent, diluent or the volume of the reaction vessel

The ratio of the amounts of organoaluminum compound (a) and catalyst complex (b) is also not critical. In general, it is selected so that the ratio of organoaluminum compound / Transition metal, expressed in moles / g-atom, above of 1 and preferably above 10.

The average molecular weight and in particular the melt index of the process according to the invention Polymers produced is by adding hydrogen and optionally one or more other molecular weight regulators, such as zinc or cadmium diethyl, alcohols or carbon dioxide, to the Polymerization medium regulated.

The specific weight of the homopolymers produced by the process according to the invention can also be obtained by adding an alkoxide of a metal from groups IVa and Va of the periodic table

I * J

^ " ¹

In this way one can use polyethylene with specifics Produce weights that are between those of the polyethylene produced by a high pressure process and those of classic high density polyethylenes.

Among the alkoxides particularly suitable for such a regulation are those of titanium and Vanadium, the radicals of which each contain 1 to 20 carbon atoms, are particularly effective. Be below called:

Ti (OCH ₃ K Ti (OC ₂ Hs) ₄ , Ti [OCH ₂ CH (CH
Ti (OC ₈ H ₁ T) ₄ and Ti (OC ₁₆ H ₃₃ ) ^

The inventive method enables the production of ethylene polymers with productivities which are comparable or also very often superior to those with known catalysts were achieved in which the transition metal compound is based on an activated alumina or halogenated alumina is fixed so it exceeds productivity, expressed in grams of polyethylene per gram of the catalyst complex (b), during homopolymerization of ethylene regularly 1000 and it can even exceed 2000 in the case of catalyst complexes that made of porous Oxidea, the one

OQ

have received prior fluorination treatment. There is also the transition metal content of the catalyst complexes (b) is very low, the concentration of disruptive catalyst residues is in the use of the polymers negligible. Therefore the polymers do not have to be cleaned any further. To this Way becomes the most difficult and costly operation to perform for the final preparation of the polymers avoided.

In addition, the catalyst complexes (b) used according to the invention have a number of completely surprising properties on:

First of all, they enable the production of polymers with melt indices, measured below normal load according to the ASTM D 1238-57 T standard, with - compared to the state of the art - a lot less high concentrations of hydrogen as a regulator or modifier, which is particularly advantageous is there so the hydrogenation of the monomer or monomers to be polymerized is reduced what the yield of the process is improved

They also enable the production of polymers with a factor L / », which is much higher than is that of polymers obtained in the presence of known catalysts.

The factor U _n is calculated using the following formula:

^u "= ik.- ^x

wherein:

- M " the average molecular weight in weight, defined by the ratio

1 PIA

M =

"'Σ / ν, ΜΓ

is where N is the number of molecules of molecular weight / W;

- ~ M _{Z is} the average molecular weight "z" defined by the ratio

² - Σ>, Μΐ

wherein N ₁ and M _{1 have} the meaning given above.

The ratio M _z / M » is determined from the fractionation values by gel permeation chromatography of a solution of 1 g / kg of the polymer in 1,2,4-trichlorobenzene at 130 ° C.

Table I.

A high factor U _n is representative of a broad molecular weight distribution in the zone of very high molecular weights.

It is therefore possible with the catalysts of the invention under particularly advantageous polymerization conditions Polymers with very low melt indices and a very high factor £ / », like him previously defined. The combination of these properties enables the production of Polymers, their use in shaping processing methods by extrusion or blow molding is particularly simple. In particular, the deformed objects have no surface defects and the phenomenon of deformation cracking, commonly referred to as "melt cracking", occurs on its own high extrusion speeds.

Examples 1 to 8 and Comparative Experiment A

A - Preparation of the catalyst complexes

Under a nitrogen atmosphere keeping a Aluminiumoxidrnonohydrat from α-type (boehmite) during 5 hours at 700 ⁰ C. An activated aluminum oxide is obtained, whose pore volume is 1.1 cmVg and whose specific surface area is 360 m ^; / g.

Fixed amounts of this activated aluminum oxide are treated at ambient temperature (25 ° C.) with fixed volumes of aqueous solutions of increasing concentrations of hydrated magnesium chloride. The hydrated magnesium chloride used is a commercially available product which corresponds to the formula MgCb · 4 H2O. The treatment is carried out in such a way that the reaction mixture retains its powdery properties. The solids obtained are then kept under a nitrogen atmosphere at 250 ° C. for 16 hours. Then 5 g of each of the solids obtained are ^{suspended in 25 cm 1 of} TiCU, and the mixture is brought to 120 ° C. for 30 minutes with vigorous stirring. The solid reaction product is separated off and washed with hexane until the chlorine ions disappear It is then dried in a stream of dry nitrogen. The particular conditions of each of these preparations, the analyzes of each catalyst complex and the magnesium content of each solid are listed in Table I. In comparative experiment A, activated aluminum oxide which had not been subjected to any MgClr treatment was summarized , used.

Used amount of activated
Aluminum oxide (g)

Applied volume of the solution of
MgCl ₂ · 4 H ₂ O (ml)

Concentration of the MgCl ₂ 4 H ₂ O solution (g / l)

Amount of magnesium used
(g / kg of aluminum oxide)

Mg content of the solid obtained
(mg atoms / m ² ) *)

13th
26th

54 15th

1.6-10 ³ 2-10

14th 12th 12th 28 24 24 72 90 108 20th 25th 30th

-3

3 x 10 "

3,3-ΙΟ ' ³

OQ

1 KA

continuation

example 1

Ti content of the catalyst complex (mg / g) 18

Cl content of the catalyst complex (mg / g) 80

Mg content of the catalyst complex (mg / g) 8.7

Table I (continued)

Example 6

18th 8th 19th 18th 96 101 111 17th 25th 28 Comparison attempt A

Amount of activated aluminum oxide used (g)

Applied volume of solution 40 of MgCl ₂ -4 H ₂ O (ml)

Concentration of the MgCl ₂ · 4 H ₂ O solution (g / l) 126

Amount of magnesium used 35 (g / kg of aluminum oxide)

Mg content of the solid obtained 3.3-10 ³ 3.5-10 (mg atoms / m ² ) *)

Ti content of the catalyst complex (.mg / g) 22

CI content of the catalyst complex (mg / g) 123

Mg content of the catalyst complex (mg / g) 28

25th
50

180
50

4.4-10 "

149

17 78

*) Content, expressed per m ^{2 of} the specific surface of the aluminum oxide before treatment at 250 C.

Interestingly, it is the fixation or binding of the magnesium on the surface of the aluminum oxide practically quantitative, taking into account the amount of magnesium used.

B - Polymerization experiments

There were two series of polymerization experiments with the catalyst complexes described above carried out under the following common conditions:

It was a certain amount (see Tables II and III) of the catalyst complex in 500 ml of hexane in a 1500 ml stainless steel autoclave, the was equipped with a paddle stirrer, transferred into suspension. To this end, 100 mg of triisobutylaluminum were added added. The temperature was brought to 85 ° C and ethylene and hydrogen under the im introduced the following specified partial pressures. the

Table II *)

The polymerization was carried out for 1 hour while maintaining a constant ethylene pressure continuous addition of ethylene carried out. After blowing off the autoclave, the values in the tables II and III specified amounts of polyethylene obtained.

The first series of polymerization experiments (Examples 1 to 8 and Comparative Experiment A) was carried out under

identical partial pressures of ethylene and hydrogen carried out. The results of these trials are compiled in Table II.

The second series of polymerization experiments (Examples 9-16 and Comparative Experiment B) was carried out with same series of catalyst complexes under different partial pressures of ethylene and hydrogen carried out, the ratio of these partial pressures being selected within the limits that a Polymer obtained whose melting index was between about 0.15 and about 0.20. The results of this Experiments are listed in Table III.

Analyzer complex prepared in Example 12 3 4 5

Comparative experiment A

Weight of the used
Complex (mg)
Weight gained
Polyethylene (PÄ), (g)
Catalytic productivity
(g PA / g catalyst complex)

Specific activity

(g PÄ / hXgTiXkg / cm ² C ₂ H ₄ )

Melt index (MI)
(g / 10 min) ***)

UiO 125 125 100 75 50 41 37 75

78 89 89 97 63 70 70 78 51

500 700 700 950 850 1400 1700 2100 680

2900 3900 3900 '5100 4600 6400 7700 10000 3990

**) **) **) 0.04 0.06 0.26 0.28 0.53 ♦ *)

90S 647/202

continuation

Catalyst complex, produced in example!
3 4 5

Comparative experiment A.

Melt index below a strong 0.27

Load (HLMI) (g / 10 min) ****)
HLMI / MI ratio

2.14 3.2

4.36
109

5.44 15.95 13.67 23.2

0.65

91 61 49 44

*) Partial pressures of ethylene (10 kg / cm ² ) and hydrogen (4 kg / cm ² ), which were the same in all tests.

**) Not measurable.

***) Measured under normal load, 2.16 kg according to the ASTM 1238-57T standard.

****) Measured under heavy load, 21.6 kg according to ASTM 1238-57T.

Table II clearly shows that the specific activity and the catalytic productivity of the Catalysts used according to the invention are better than under identical polymerization conditions those of catalysts of the prior art based on activated alumina (the comparative experiment A was carried out with a catalyst complex made in the same manner as the catalyst complexes of Examples 1 to 8 have been prepared

Table III

was, however, without treating the activated aluminum oxide with magnesium chloride) as soon as the miignesium content of the solid exceeds 2 · 10 ^-3 mg-atom / m ² on specific surface. It was also found that the melt index was the same as that obtained

Polymers with all other polymerization conditions kept constant proportional to the magnesium content the catalyst complexes grew.

270 550

550

Weight of the used
Catalyst complex (mg)

Partial pressure of ethylene
(kg / cm ² ) (1)

Partial pressure of hydrogen
(kg / cm ² ) (2)

Ratio (2) / (l)

Weight of the gained
Polyethylene (g)

Catalytic productivity
(g PA / g catalyst complex)

Melt index (g / 10 min) (3)
Melt index under strong
Load (g / 10 min) (4)
Ratio (4) / (3)
Factor £ / "

The tests compiled in Table ÜI show that the production of polyethylene is possible according to the invention. Melt indices that are in the of the same order of magnitude as the melt indexes of using catalysts of the prior art Technique produced polyethylenes, with much less molecular weight regulator (hydrogen) used and the catalytic productivity is nevertheless increased.

The F i g. 1 of the drawing shows that the catalyst complexes obtained from solids, deiren magnesium content varies from about 1 · 10 ^-3 to 5 <K) ^-3 mg / atom / m ² on specific surface, the lowering of the ratio of the partial pressures of hydrogen and ethylene by a factor of about 10, with polyethylenes with comparable melt indices being obtained. Also show the

example
9 10 11th 12th 159 157 105 13th 14th 15th 16 Comparison
attempt B Catalyst complex, prepared according to
12 3 4 10 10 10 example
5 6th 7th 8th Comparison
attempt A 250 10 10 8th 108 50 39 36 210 1
88 1
83 0.8
110 10 10 10 10 8th 15th 5 3 3 2 15th 1.9
67 0.5
111 0.3
94 OJ
78 52
98 1.9
96

700

1000 1900 2000 2700 720

0.10 0.15 0.20 0.18 0.20 0.28 0.25 0.14 0.17
9.02 14.42 18.67 16.27 12.01 10.93 9.28 8.22 14.8

90 96 94 90 60 61 62 59 87 15th 13th 21 28 26th 16 11th 13th 11th

Examples 9 to 16 and FIGS. 2 of the drawing that with the same change in the magnesium content, the factor U _{w of} the polyethylene obtained is always higher

than the factor U _n . of polyethylene, which was obtained in the presence of the Katälysatorkomplexes according to Comparative Experiment A, and that an optimum for the magnesium content of the solids is present, which is a maximum of the values for the factor U _w

is equivalent to.

Examples 17 and 18
and comparative experiment C

A - Preparation of the catalyst complexes

65

Alumittium oxide monohydrate of the Λ-type (boehmite) is mixed with about 4% by weight of NH ₄ F, the mixture is brought to a temperature of 700 ° C. and is maintained at this temperature

Maintain temperature for 1 hour. The fluorinated aluminum oxide obtained in this way is subjected to a thermal treatment which is carried out at 700 ^° C. for 5 hours under a nitrogen atmosphere. Its specific surface is 250 m ² / g and its pore volume is 1 cm ³ / g.

Fixed amounts of this fluorinated alumina are treated with aqueous solutions of MgC ^ 4 H2O in the same manner as for the preparation of the catalyst complexes of Examples 1-8. The solids obtained are then kept for 6 hours at 250 ^° C. under a nitrogen atmosphere. Finally, they are treated with TiCl in the same manner as in Examples 1 to 8 except that the treatment temperature is 130 ⁰ C and the reaction product is subjected to five extractions with boiling TiCLt.

Table IV

B - Polymerization experiments
The washed and dried products are used as catalyst complexes in Polymerisationsversuchun which were carried out under the same conditions that are detailed in paragraph B of Examples 1 to 8. The particular conditions for the preparation of these catalyst complexes, the results of their analysis, the particular conditions and results of the polymerization and the properties of the polyethylenes obtained are summarized in Table IV, in which the results are also listed which were obtained with a comparative complex described in in the same way as the catalyst complexes described above, but omitting the treatment step of the fluorinated aluminum oxide with magnesium chloride (Comparative Experiment C).

Special conditions

Example 17

BeisDiel 18

Comparative experiment C

Amount of magnesium used
(g Mg / kg fluorinated aluminum oxide)

Mg content (mg atoms of the solid obtained / m ² ) (before treatment at 250 ° C)

Ti content of the catalyst complex (mg / g)
F content of the catalyst complex (mg / g)
CI content of the catalyst complex (mg / g)
Mg content of the catalyst complex (mg / g)

Weight of the catalyst complex used (mg) Amount of triisobutylaluminum used (mg)

Partial pressure of ethylene (1) (kg / cm ² )

Partial pressure of hydrogen (2) (kg / cm ² )

Ratio (2) / (l)

Weight of polyethylene recovered (PÄ) (g)

Catalytic productivity (g PA / g catalyst complex) Melt index (g / 10 min) (3)

Melt index under heavy load (g / 10 min) (4) Ratio (4) / (3)

Factor U _x

15th 25th - 2.3 x 10 " ³ 3.7-10 " ³ - 13th 14th 7.7 23 22nd 35 61 87 24 14th 23 - 107 51 140 100 100 200 10 10 8th 10 5 15th 1 0.5 1.9 80 99 103 750 2000 736 0.10 0.11 0.23 7.98 10.15 11.5 80 92 50 12th 13th 10

From Table IV it can again be seen that there is an optimum for the magnesium content of the solids with the aid of which the KalPlysatorkompIexe are prepared according to the process of the invention, which corresponds to a maximum of the Kalalytic productivity and the production of a polyethylene at a much lower ratio of Partial pressures of hydrogen and ethylene made possible, which has a comparable melt index and a higher factor U _w compared to polyethylene, which was obtained in the presence of the comparative catalytic complex according to comparative experiment C.

Example 19

A complex oxide of the general formula MgO * Al2O3 (spinel) was subjected to a study carried out under a stream of dry nitrogen at 900 ⁰ C for 5 hours thermal treatment. A complex oxide was obtained which was distinguished by a specific surface area of 290 mVg and an internal porosity of 1.5 cm ³ / g. This complex oxide was treated with an aqueous solution of MgO 2 · 4 H2O in the same manner as in Examples 1 to 8, the amount of magnesium used being equal to 15 g of magnesium / kg of complex oxide. The magnesium content of the solid obtained, which can only be ascribed to a fixation of the magnesium chloride, was therefore 4.6 ³ mg atoms Mg / m ² on the specific surface area Reaction with TiCU, which was carried out as indicated in Examples 2 to 8, the catalyst complex obtained contains 19 mg of titanium and 111 mg of chlorine per g. A polymerization verse carried out with 41 mg of this complex under the same conditions specified in paragraph B of Examples 1 to 8 and under partial pressures of ethylene and hydrogen of 10 and 2 kg / cm ^2, respectively, resulted in 68 g of polyethylene, the melt index of which was 0.16 g / 10 min and its melt index under heavy load was 8.07 g / 10 min. The catalytic productivity was 1650 g PA / g catalyst

gate complex, and the specific activity 870Og PA / h χ g Ti χ kg / cm ² C ₂ H ₄ . The factor L ^ of the polyethylene was 6.

Comparative experiment D

For comparison, it should be stated that one under the conditions given in Example 19 was prepared with 60 mg of a catalyst complex, which had been prepared in the same way, but without treating the complex oxide with a magnesium halogen compound (Ti content = 13 mg / g). The polymerization test carried out made it possible to obtain 25 g of polyethylene with a non-measurable melt index and a melt index under heavy loads of 0.61 g / l 0 min. The catalytic activity and the specific activity were 420 g PA / g catalyst complex and 3200 g PA / h χ g Ti kg / cm ² C ₂ H _4, respectively.

Example 20

To prepare the catalyst complex used in this experiment, 12.4 g of magnesium ethylate Mg (OC ₂ Hs) _{2 were added} to 17 g of titanium tetrabutylate Ti (OC ₄ H ₉ I ₄ , and the mixture was ^{heated to 130 °} C. for 6 hours while stirring In the mixture the atomic ratio Ti / Mg was 0.5at-g / at-g with ± 10% error as a result of impurities contained in the compounds used ° C., 60 cm ^{3 of} hexane were added to the cooled mixture, and the whole was stirred at this temperature for 1 hour. The solution thus obtained was brought to a volume of 120 cm ^{3 by adding hexane}

18.5 cm ^{3 of} this solution, ie a volume containing about 0.4 g of magnesium, was gradually introduced into 100 cm ^{3 of} a suspension containing 21 g of a fluorinated alumina prepared according to paragraph A of Examples 17 and 18 that so formed mixture for 15 minutes at ambient temperature was stirred, then decant was left and anschliebend the supernatant removed the analysis showed a content of on the so obtained solid, fixed or bound magnesium of 2.2 ■ IO ³ mat-g / m ² of specific Surface. The solid thus obtained was ³ TiCl ₄ first converted into 140 cm under stirring for 2 hours at ambient temperature in the suspension followed by removal of the first TiCl batch in the same volume of TiCl ₄ for 30 minutes at 120 ⁰ C. Finally, the catalyst complex was collected , washed with hexane until chlorine ions disappeared in the washing liquid, and dried under a stream of dry nitrogen. It contained 18 g of titanium. 21 g fluorine, 65 g chlorine and 14 g magnesium per kg. A polymerization test carried out under the same conditions as the first series of polymerization tests (Examples 1 to 8) with 55 mg of the catalyst complex made it possible to produce 117 g of polyethylene, its melt index 0.14 g / 10 min and its melt index under heavy loads 11.03 g / 10 min. Their ratio was therefore about 79, and the U _x factor of the polyethylene was 11. The catalytic productivity was 2100 g PA / g catalyst complex and the specific activity 11 700 g PA / h g Ti χ kg / cm ² C ₂ H _4th

If the results of this experiment are compared with those of comparative experiment C, it is again evident that in the presence of the catalyst complexes used according to the invention it is possible to obtain a polyethylene with a comparable melt index and a higher factor U _w at a much lower ratio of the partial pressures of hydrogen and ethylene.

Example 21

To prepare the catalyst complex used in this experiment, the hydrated magnesium chloride used in Examples 1 to 8 was first heated to 185 ° C. until the monohydrate was obtained. 15.5 g of magnesium chloride monohydrate obtained in this way were added to 85 g of titanium tetrabutoxide, and the mixture was heated at 130 ° C. for 6 hours with stirring Atomic ratio Ti / Mg 2at-g / at-g with ± 10% error as a result of impurities contained in the compounds used. To the cooled mixture were added 300 cm ³ of hexane were added, and the whole was stirred at 90 ⁰ C for 1 hour, heated The soluble fraction of the cooled mixture was gewonrren; it was analyzed to contain 6.5 g Mg / l

20 g of a fluorinated aluminum oxide prepared according to paragraph A of Examples 17 and 18 were suspended in 100 cm ^{3 of} hexane and then ^{treated with 56 cm 3 of} the soluble fraction of the mixture described above 21 was described. The solid obtained contained 23 × 10 ^-3 mg atoms of Mg / m ² on a specific surface. The catalyst complex contained 24 g titanium, 23 g fluorine and 73 g chlorine as well as 11 g magnesium per kg. A polymerization experiment carried out under the same conditions as in Example 21 with 52 mg of the catalyst complex made it possible to produce 69 g of polyethylene with a melt index (1) of 0.18 g / 10 min and a melt index under heavy loads (2) of 10.67 g / 10 min and a factor U _w of 19. The ratio (2) / (l) is therefore approximately equal to 59. The catalytic productivity is 1350 g PA / g catalyst complex and the specific activity is 5600 g PA / h χ g Ti χ kg / cm ² C ₂ H ₄ .

Example 22

12 g of an activated aluminum oxide prepared as in paragraph A of Examples 1'λ ^{8 was treated with 24 cm 3 of} a solution which contained 18 g / l magnesium methylate, Mg (OCHs) ₂ , in methanol. that the reaction mixture retained its pulverulent character the resulting solid was dried in vacuo at 50 ° C for 1 hour his magnesium content was 1.1 - IO ³ mat-g / m ² of specific surface area. This solid was then treated with TiCl ₄ , as described in paragraph A of Examples 1 to 8. According to the analysis, the catalyst complex obtained contained 20 g of titanium, 90 g of chlorine and 9.7 g of magnesium per kg.

One under the general conditions mentioned in paragraph B of Examples i to S, but with 102 mg of the catalyst complex and under partial pressures of ethylene and hydrogen of 10 kg / cm ² and 6 kg / cm ^{2, respectively}

24

A polymerization test carried out enabled the recovery of 71 g of polyethylene with a melt index (I) of 0.19 g / 10 min, a melt index under heavy load (2) of 12.65 g / 10 min and a factor U * of 16. The ratio (2) / (l) is therefore about 67. The catalytic productivity is 700 g PA / g catalyst complex and the specific activity is 3500 g PA / h χ gTi χ kg / cm ² C ₂ H ₄ .

Example 23

This example relates to the copolymerization of ethylene with propylene and butene- (I).

It became a catalyst complex according to the working method of Examples 1 to 8A, but with a fluorinated aluminum oxide as the activated aluminum oxide was used as described in Examples 17 and 18.

The catalyst complex obtained in this way contained 17 g of titanium, 81 g of chlorine, 23 g of fluorine and 20 g of magnesium per kg. The content of the obtained solid of magnesium prior to the treatment at 250 ⁰ C was 3.5 χ ΙΟ- ³ mg-atom / m ^2.

There were two attempts to copolymerize ethylene with propylene on the one hand and n-butene- (l) on the other hand carried out under the following conditions:

- 1.5 l stainless steel autoclave,

- diluent: 0.5 1 hexane,

- temperature: 85 ° C,

- Duration: 1 hour,

- Activator: 100 mg triisobutyl aluminum,

- Ethylene partial pressure: 10 kg / cm ² .

The particular conditions for these experiments and the results obtained are given in Table V. compiled:

Table V

Comonomer

Propylene n-butene- (l)

Amount of comonomer introduced (mmol) Amount of catalyst complex used (mg) Hydrogen partial pressure (kg / cm ² )

Hourly production of copolymer (g) Practical activity (g copolymer / hXg catalyst complex χ kg / cm ² C ₂ H ₄ ) Specific activity (g copolymer / hXgTi X kg / cm ² C ₂ H ₄ )
Melt index (MI) of the obtained copolymer (g / 10 min)

Melt index under heavy load (HLMI) of the copolymer obtained (g / 10 min)

HLMI / MI ratio

Specific weight of the copolymer obtained (kg / dm ³ )

60 530 76 56 4th 2 67 36 880 640 5150 3770 0.50 0.36 29.4 16.62 59 46 0.957 0.934

For this purpose 2 sheets of drawings

Claims (1)

It is already known to use catalysts which contain a transition metal compound and an organometallic compound for the low-pressure polymerization of olefins. It is also known to use the transition metal compound on oxide supports with a large pore volume, such as aluminum oxides (cf. the documents laid out in Belgian patent 7 68271) and halogenated aluminum. 1. Process for the low pressure polymerization of Ethylene or for the low pressure copolymerization of ϊ Ethylene and ". -Olefins having 3 to 6 carbon atoms in the presence of catalysts