GB1582287A

GB1582287A - Process catalyst and catalyst component for the manufacture of homopolymers and copolymers of a-monoolefins

Info

Publication number: GB1582287A
Application number: GB3083277A
Authority: GB
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1976-07-23
Filing date: 1977-07-22
Publication date: 1981-01-07
Also published as: DE2633109C2; ATA535377A; JPS5313690A; FR2359156A1; ES460960A1; AT354726B; IT1076790B; BE857100A; DE2633109A1; FR2359156B1

Description

(54) PROCESS, CATALYST AND CATALYST COMPONENT FOR THE MANUFACTURE OF HOMOPOLYMERS AND COPOLYMERS OF xx-MONOOLEFINS (71) We, BASF AKTIENGESELLSCHAFT, a German Joint Stock Company of 6700 Ludwigshafen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement: The present invention relates to a process for the manufacture of a homopolymer of an a-monoolefin of 2 to 6.carbon atoms or a copolymer of two or more such a-monoolefins by polymerizing the monomer or monomers at from 30 to 200"C and from 0.1 to 200 bars by means of a Ziegler catalyst system comprising 1 a vanadium-containing catalyst component, 2 a metal compound of the general formula MeRm-nXn where Me is aluminum, magnesium or zinc, preferably aluminum, R is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms and preferably alkyl of 2 to 8 carbon atoms, X is chlorine, bromine and/or hydrogen, preferably chlorine and/or hydrogen, m is the valency of the metal Me and n is a number from 0 to m- 1, preferably from 0 to 1, with or without (3) a halohydrocarbon of 1 to 12 carbon atoms, with the provisos that the atomic ratio of vanadium from catalyst component (1) to metal (Me) from catalyst component (2) is from 1 : 0.1 to 1 : 400, preferably from 1 : 4 to 1 : 200 and, where component (3) is present, the molar ratio of catalyst component (3) to metal (Me) from catalyst component (2) is from 1: 0.1 to 1: 60, preferably from 1: 1 to 1: 25.

Processes of this nature have proved successful in industrial operation but still suffer from a number of minor or major shortcomings. For example, the vanadium-containing catalyst component (1) to be employed is in many cases unsatisfactory. This is also true of those vanadium-containing catalyst components which are manufactured starting from a finely divided carrier, i.e. supported catalysts which, as is known, are generally to be preferred, in industrial practice, to other vanadium-containing catalyst components, since they result in satisfactory operation and satisfactory results.

The present invention seeks to provide vanadium-containing catalyst components (1) which are manufactured starting from a finely divided carrier and which prove advantageous in operation and in the result obtained, for example which make it possible, even when using only relatively small amounts of hydrogen as a regulator, to reduce the molecular weight of the polymers relatively substantially (which is above all of importance in dry-phase polymerization processes) and which, for example, have the result of giving polymers which possess particularly advantageous morphological properties.

We have found that this good results may be achieved by providing a vanadium-containing catalyst component (1) which is obtained by first bringing a specific finely divided silicon oxide carrier into contact with a solution of a specific aluminum compound, then bringing the resulting solid-phase product into contact with a specific solution obtained from a specific alcohol and a vanadium trihalide, and finally isolating a solid product from the resulting dispersion by evaporation.

According to the present invention there is provided a process for the manufacture of a homopolymers of an a-monoolefin of 2 to 6 carbon atoms or a copolymer of two or more such a-monoolefins by polymerizing the monomer or monomers at from 30 to 2000C and from 0.1 to 200 bars by means of a Ziegler catalyst System comprising (1) a vanadium-containing catalyst component, (2) a metal compound of the general formula Me Rm-nXn where Me is aluminium, magnesium or zinc, preferably aluminum, R is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms and preferably alkyl of 2 to 8 carbon atoms, X is chlorine, bromine and/or hydrogen, preferably chlorine and/or hydrogen, mis the valency of the metal Me and n is a number from 0 to m- 1, preferably from 0 to 1, with or without (3) a halohydrocarbon of 1 to 12 carbon atoms, with the provisos that the atomic ratio of vanadium from catalyst component (1) to metal (Me) from catalyst component (2) is from 1: 0.1 to 1: 400, preferably from 1: 4 to 1: 200 and, where component (3) is present, the molar ratio of catalyst component (3) to metal (Me) from catalyst component (2) is from 1: 0.1 to 1 : 60, preferably from 1 : 1 to 1 : 25, in which process the vanadium-containing catalyst component (1) employed is the solid-phase product (VI) which has been obtained by first (1.1) bringing into contact with one another (1.1.1) a finely divided, porous, inorganic oxidic material (I), which has a particle diameter of from 1 to 1,000, preferably from 1 to 400, 1lem, a pore volume of from 0.3 to 3, preferably from 1 to 2.5, cm /g and a surface area of from 100 to 1,000, preferably from 200 to 500, m2/g and has the formula sio2 .aAl203, where a is a number from 0 to 2, especially from 0 to 0.5 and (1.1.2) an aluminium compound (II) of the general formula AlR'3.pYp where R' is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms and preferably alkyl of 1 to 8 carbon atoms, Y is chlorine, bromine, hydrogen and1or OR", preferably chlorine, hydrogen and/or OR", R" is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms and preferably alkyl of 1 to 8 carbon atoms, and p is a number from 0 to 3, preferably from 0 to 2, the aluminum compound being dissolved in an organic solvent, so as to form a solid-phase product (III), with the proviso that the weight ratio of inorganic oxidic material (I) employed to aluminum compound (II) employed is from 1: 0.05 to 1:10, preferably from 1: 0.2 to 1: 3, and then (1.2) bringing into contact with one another 1.2.1 the solid-phase product (III) obtained in stage (1.1) and 1.2.2 a solution (IV) obtained on bringing together 100 parts by weight of an alcohol (IVa) of the general formula Z-OH, where Z is a saturated hydrocarbon radical of 1 to 8 carbon atoms, especially of 1 to 6 carbon atoms, and preferably alkyl of 1 to 4 carbon atoms, and from 0.02 to 5, preferably from 0.05 to 3.5, parts by weight (calculated as vanadium) of a vanadium trihalide (IVb), where halogen is chlorine and/or bromine, preferably a vanadium trichloride, to form a dispersion (V), with the proviso that the weight ratio of solid-phase product (III, calculated as inorganic oxidic material I) to vanadium in the vanadium trihalide (IVb)isfrom 1: 0.01 to 1: 0.2,preferablyfrom 1: 0.03to1 :0.15,andthenevaporatingthe dispersion (V) at below 200"C, preferably below 1200C, and above the melting point of the alcohol (IVa) employed, until a dry consistency is reached, i.e. the solid product (VI) is formed.

In relation to comparable conventional processes, the process of the invention is distinguished by the fact that it provides technical and economic improvements. Thus, even the manufacture of the vanadium-containing catalyst component is simpler because it can be carried out in two stages only; since furthermore it is not necessary - as is the case in other processes - to use an excess of the vanadium compound, the process also provides a substantial advance in respect of economy and of pollution of the environment. In the actual polymerization it is a great advantage that the molecular weight of the polymers can be lowered by a relatively substantial amount even with relatively small amounts of hydrogen as the regulator; this is an effect which is particularly marked when a halohydrocarbon (3) is also present as a promoter, above all in dry-phase polymerization processes. Furthermore, when carrying out the polymerization by means of the new catalyst system, a substantial advantage is achievable due to the fact that the polymerization has a relatively high productivity (expressed as amount by weight of polymer per unit by weight of catalyst) and hence polymers having a low halogen content and low vanadium content can also be obtained. The inherently undesirable catalyst constituents remaining in the polymer (i.e. vanadium and halogen) are in such small amounts that they are no longer objectionable and their removal, which would require a separate process step, can be dispensed with. In addition, the polymers obtainable by the process of the invention exhibit further improvements in properties; for example, their morphology conforms to an important number of requirements, namely: the content of dust-like polymer particles is very low, i.e. the dust explosion hazard is greatly reduced, and furthermore the particle shape is such that the material can not only be stirred easily (which is of importance during manufacture of the polymer) but also has a high tap density and good particle flow characteristics, both being advantages in respect of the handling of the polymers.

The following are further details of the process according to the invention.

The polymerization process as such can, providing the special aspects characterized above are adhered to, be carried but in virtually all relevant conventional technological embodiments, i.e. as a batchwise cyclic or continuous process, which processes may be, for example, suspension polymerizations, solution polymerizations or dry-phase polymerizations. The technological embodiments mentioned, i.e. the technological variants of the Ziegler polymerization of olefins are well-known from the literature and from practical experience, so that they do not require more detailed comments here. However it may be noted that the new vanadium-containing catalyst component (1), like similar conventional catalyst components, can, for example, be brought together with the catalyst component (2) outside or inside the polymerization vessel; in the latter case this may be effected by, for example, spatially separate introduction of the components, which may furthermore be handled in the form of a suspension (catalyst component (1)) or solution (catalyst component (2)). It is also possible, for example, to employ the catalyst component (1) or the combined catalyst components (1) and (2) in the form of particles provided with a wax coating, this being a method which can be of advantage in the dry-phase polymerization process.

As has been found, the advantageous properties of the process according to the invention manifest themselves particularly if the process is carried out as a dry-phase polymerization.

As regards the new vanadium-containing catalyst component (1) itself, the following may be noted: The component is prepared in two stages which are referred to in both the preceding and following text by (1.1) and (1.2). (1.1) In this first stage, a finely divided inorganic oxidic material (I) of the type defined above and dissolved aluminum compound (II) of the type defined above are brought into contact with one another, whereupon a solid-phase product (III) forms.

Specifically, an advantageous procedure is the following: a suspension of from 1 to 50 per cent strength by weight, preferably of about 20 per cent strength by weight, of the inorganic oxidic material (I), and a solution of from 5 to 80 per cent strength by weight, preferably of about 30 per cent strength by weight, of the aluminum compound (II) are first prepared in separate batches, suitable suspension media and solvents being, in particular, hydrocarbons, above all relatively low-boiling alkane hydrocarbons, e.g. hexanes, heptanes or gasolines.

Thereafter the suspension and the solution are combined in such ratios as to give the desired weight ratio. To combine them, the solution is in general introduced into the suspension whilst stirring, since this procedure is preferable from a practical point of view to the converse procedure, though the latter is also feasible. At from -10 to 140 , especially at about 20"C, the formation of the solid-phase product (III) takes place within a period of from 5 to 300 minutes, especially from 15 to 120 minutes. This product can advantageously be purified before being processed further. For this, two methods are available, inter alia: according to the first method the product (III) is separated from the liquid phase by filtration and is washed with pure liquid (which may be of the type also used as the suspension medium or solvent) after which it is dried, if appropriate under reduced pressure. Alternatively, the product is digested and decanted repeatedly, using as the liquid, for example, the alcohol (IVa) employed as the solvent for the second stage (1.2). It has been found that in a number of cases it suffices to isolate the product (III) in a simple manner by driving off the volatile constituents from stage (1.1), i.e. the suspension medium or solvent, under reduced pressure at from 0 to 100"C.

(1.2) In this second stage, the solid-phase product (III) obtained according to (1.1) and a specific solution (IV), defined above, are brought into contact with one another, resulting in the formation of a dispersion (V), which is then evaporated until it assumes a dry consistency.

Specifically, the procedure which may be followed is to combine the product (III), undiluted or dispersed in an alcohol (advantageously an alcohol as defined under (IVa), the solids content of the dispersion being not less than 5 per cent by weight) with the solution (IV). It is advantageous if after the combination the batch is kept at from 10 to 1600C, especially from 20 to 1200C, for a period of from 5 to 120 minutes, especially from 20 to 90 minutes, and the dispersion (V) formed is only then evaporated.

The solution (IV) itself can be prepared by the conventional methods and to this extent presents no peculiarities.

As the final measure in the manufacture of the vanadium-containing catalyst component (1), the dispersion (V) is evaporated until it assumes a dry consistency, the dry solid-phase product (VI) thus obtained being the new catalyst component (1) according to the invention.

Specifically, the procedure which may be followed is that which is conventionally used for evaporating dispersions gently, provided the above temperature conditions are observed.

This means that it is generally advantageous - and in the case of relatively high alcohols (IVa) at times essential - to effect the evaporation under reduced pressure. A rule of thumb is that the temperature/pressure combination should be so chosen that the evaporation process has ended after from about 1 to 10 hours. It is also advantageous to carry out the evaporation under conditions such that the treated material always remains homogeneous; rotary evaporators, for example, are suitable for this purpose. A residual amount of alcohol, for example an amount bonded by complex formation, is in general not detrimental to the solid-phase product (VI).

The new vanadium-containing catalyst components (1), i.e. the solid-phase product (VI), can be employed, within the scope of the process defined at the outset, to manufacture the polymers also referred to there, by the methods conventionally employed for vanadiumcontaining compounds in the Ziegler polymerization of olefins. To this extent, the process according to the invention thus exhibits no peculiarities, and reference may be made to the methods well-known from the literature and from practical experience. It merely remains to record that the process is particularly suitable for the preparation of homopolymers of ethylene and that where it is used to prepare copolymers of ethylene with higher a-monoolefins or to prepare homopolymers of higher a-monoolefins, the monoolefins are above all propene, 1-butene, 4-methyl-1-pentene and 1-hexene. The molecular weights of the polymers can be regulated in the relevant conventional manner, especially by means of hydrogen as the regulator.

As regards the composition aspect of the new vanadium-containing catalyst component (1), the following may be noted specifically: (1.1) The inorganic oxidic material (I) to be employed is in general an alumosilicate or especially a silicon dioxide; it is important that the material should have the requisite properties and should be as dry as possible (no further weight loss after 6 hours at 1600C under a pressure of 2 mm Hg). Particularly suitable inorganic oxidic materials are those which are obtained in accordance with the first stage (1) of the process described in German Laid-Open Application DOS 2,411,735, especially if the starting materials used are hydrogels obtained by the process described in German Laid Open Application DOS 2,103,243.

Examples of suitable aluminum compounds (II) to be employed are aluminum trialkyls, aluminum dialkyl-hydrides, aluminum dialkyl chlorides, aluminum alkyl-dichlorides, aluminum trichloride, aluminum trialkoxide, aluminum dialkoxy-chloride, aluminum alkoxy-dichloride, alkyl-dialkoxy-aluminum and dialkyl-alkoxy-aluminum. Aluminum compounds to be singled out as being particularly suitable are those of the formulae Al(i C4H9)2H, Al(C2H5)2Cl, Al(C2H5)1.5Cl1.5, Al(C2H5)Cl2, Al(OC2H5)2C2H5 and Al(OC2H5)(C2H5)2.

The aluminum compounds (II) can be employed as individual compounds, mixtures of two or more individual compounds, and sesqui-compounds.

(1.2) The alcohols (IVa) to be employed may be, for example: methanol, ethanol, the propanols, the butanols and cyclohexanol. Methanol, ethanol, isopropanol and cyclohexanol, for example, have proved particularly suitable.

The alcohols (IVa) can be employed in the form of individual compounds or of mixtures of two or more individual compounds.

The vanadium trihalide (IVb) to be employed may be a trihalide conventionally used in Ziegler catalyst systems.

Regarding the catalyst compound (2) it is to be noted that the relevant conventional compounds are suitable; examples of suitable compounds are Al(C2H5)3, Al(C2H5)2Cl, Al(C2H5)2H, Al(i-C4H9)3, Al(n-C4H9)3, Al(C8Hl7)3 and isoprenyl-aluminum.

The catalyst component (3), i.e. the promoter, may also be, for example, one of the relevant conventional halohydrocarbons; alkyl-aromatics chlorinated in the alkyl radical, e.g. sidechain-chlorinated alkylbenzenes, are particularly suitable. Benzyl chloride and benzal chloride are to be preferred - and amongst these benzyl chloride is exceptionally suitable.

In conclusion, it should be noted that the vanadium-containing catalyst component (1) according to the invention, i.e. the product (VI), and its precursors and intermediates, mentioned above, are sensitive to hydrolysis and oxidation. To this extent, the substances should thus be handled with the relevant conventional precautionary measures for Ziegler catalysts (e.g. exclusion of moisture and use of an inert gas atmosphere.

EXAMPLE 1 Manufacture of the vanadium-containing catalyst component (1): (1.1)First stage of manufacture The starting material is a suspension of 10 parts by weight of silicon dioxide (SiO2, particle diameter 2-40 m, pore volume 2.1 cm3/g, surface area 420 m2/g) in 100 parts by weight of n-heptane and a solution of 4.3 parts by weight of diethyl-aluminum chloride in 10 parts by weight of n-heptane.

The above solution is introduced into the above suspension at 250C in the course of 30 minutes, whilst stirring, and the batch is then kept at 250C for a further 60 minutes, whilst stirring.

The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing with n-heptane and drying under reduced pressure; it is employed in the second stage (1.2).

(1.2) Second stage of manufacture The solid-phase product obtained in stage (1.1) is suspended in 120 parts by weight of methanol whilst stirring and cooling to -10 C.

This suspension is combined with a solution of 2.55 parts by weight of VCl3 in 95 parts by weight of methanol. The resulting suspension is stirred for 30 minutes at 30"C and the solid-phase reaction product formed is then isolated by driving off the volatile constituents in a rotary evaporator which is brought to an operating pressure of 20 mm Hg and an operating temperature of 20"C. The analysis of the resulting product, i.e. of the vanadium-containing catalyst component (1), gives a vandium content of 4.4 per cent by weight and a chlorine content of 14.1 per cent by weight.

Polymerization: 0.044 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.24 part by weight of isoprenyl-aluminum (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 34).

The Ziegler catalyst system thus obtained is introduced into a stirred autoclave which is charged with 300 parts by weight (corresponding to about 40% of its capacity) of heptane.

The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant value: ethylene pressure = 30.5 bars, hydrogen pressure = 1 bar, temperature = 95"C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 2 The vanadium-containing catalyst component (1) is manufactured as described in Example 1.

Polymerization: 0.1 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.26 part by weight of A1(CsH17)3 (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1 : 8).

The Ziegler catalyst system thus obtained is introduced into a stirred autoclave which is charged with 80 parts by weight (corresponding to about 20% of its capacity) of finely divided polyethylene. The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant value: ethylene pressure = 30.5 bars, hydrogen pressure = 2 bars, temperature = 100"C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 3 Manufacture of the vanadium-containing catalyst component (1): (1.1) First stage of manufacture The starting material is a suspension of 30 parts by weight of silicon dioxide (SiO2, particle diameter 2-40 clam, pore volume 1.9 cm3/g, surface area 460 m2/g) in 170 parts by weight of n-heptane and a solution of 12 parts by weight of diethyl-aluminum chloride in 10 parts by weight of n-heptane.

The above solution is introduced into the above suspension at 15"C in the course of 15 minutes, whilst stirring, and the batch then kept at 250C for a further 60 minutes, whilst stirring.

The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing with n-heptane and drying under reduced pressure; it is employed in the second stage (1.2) Second stage of manufacture The solid-phase product obtained in stage (1.1) is suspended in 160 parts by weight of methanol whilst stirring and cooling to -100C.

This suspension is combined with a solution of 7.65 parts by weight of VCl3 in 160 parts by weight of methanol. The resulting suspension is stirred for 10 minutes at 250C and the solid-phase reaction product formed is then isolated by driving off the volatile constituents in a rotary evaporator which is brought to an operating pressure of 30 mm Hg and an operating temperature of 20"(The analysis of the resulting product, i.e. of the vanadium-containing catalyst component (1), gives a vanadium content of 4.5 per cent by weight and a chlorine content of 15.0 per cent by weight.

Polymerization: 0.055 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.2 part by weight of Al(C4H9)3 (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 21).

The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant Value: ethylene pressure = 29.5 bars, hydrogen pressure = 2 bars, temperature = 950 C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 4 Manufacture of the vanadium-containing catalyst component (1): (1.1) First stage of manufacture The starting material is a suspension of 10 parts by weight of silicon dioxide (SiO2, particle diameter 2-40,um, pore volume 2.0 cm3/g, surface area 410 m2/g) in 100 parts by weight of n-heptane and a solution of 4.3 parts by weight of diethyl-aluminum chloride in 10 parts by weight of n-heptane.

The above solution is introduced into the above suspension at - 100 C in the course of 15 minutes, whilst stirring, and the batch is then kept at 250C for a further 60minutes, whilst stirring.

The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing with n-heptane and drying under reduced pressure; it is employed in the second state t1.28 } 2 Second stage of manufacture The solid-phase product obtained in stage (1.1) is suspended in 120 parts by weight of methanol whilst stirring and cooling to -200C.

This suspension is combined with a solution of 2.55 parts by weight of VCl3 in 95 parts by weight of methanol. The resulting suspension is stirred for 15 minutes at 600C and the solid-phase reaction product formed is then isolated by driving off the volatile constituents in a rotary evaporator which is brought to an operating pressure of 20 mm Hg and an operating temperature of 60"C. The analysis of the resulting product, i.e. of the vanadium-containing catalyst component (1), gives a vanadium content of 4.2 per cent by weight and a chlorine content of 14;0 per cent by weight.

Polymerization: 0.1 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.16 part by weight of Al(i-C4Hg)3 (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about1: 10).

The Ziegler catalyst system thus obtained is introduced into a stirred autoclave which is charged with 80 parts by weight (corresponding to about 20 % of its capacity) of finely divided polyethylene. The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant value: ethylene pressure = 30.5 bars, hydrogen pressure = 2 bars, temperature = 100"C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 5 Manufacture of the vanadium-containing catalyst component (1): (1.1) First stage of manufacture The starting material is a suspension of 10 parts by weight of silicon dioxide (SiO2, particle diameter 2-40,am, pore volume 2.1 cm3/g, surface area 390 m2/g) in 100 parts by weight of n-heptane and a solution of 4.3 parts by weight of diethyl-aluminum chloride in 10 parts by weight of n-heptane.

The above solution is introduced into the above suspension at -10 C in the course of 30 minutes, whilst stirring, and the batch is then kept at 25"C for a further 50 minutes, whilst stirring.

The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing with n-heptane and drying under reduced pressure; it is employed in the second stage 1.2) Second stage of manufacture The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing wit

(1.2) Second stage of manufacture The solid-phase product obtained in stage (1.1) is suspended in 110 parts by weight of isopropanol whilst stirring and cooling to -100C.

This suspension is combined with a solution of 2.55 parts by weight of VC13 in 95 parts by weight of isopropanol. The resulting suspension is stirred for 30 minutes at 250C and the solid-phase reaction product formed is then isolated by driving off the volatile constituents in a rotary evaporator which is brought to an operating pressure of 20 mm Hg and an operating temperature of 25"C. The analysis of the resulting product, i.e. of the vanadium-containing catalyst component (1), gives a vanadium content of 3.58 per cent by weight and a chlorine content of 13.0 per cent by weight.

Polymerization: 0.085 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.09 part by weight of Al(C2H5)3 (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminium) from catalyst component (2) of about 1: 13).

The Ziegler catalyst system thus obtained is introduced into a stirred autoclave which is charged with 80 parts by weight (corresponding to about 20%of its capacity) of finely divided polyethylene. The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant value: ethylene pressure = 29.5 bars, hydrogen pressure = 3 bars, temperature = 100"C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 6 Manufacture of the vanadium-containing catalyst component (1): (1.1) First stage of manufacture The starting material is a suspension of 200 parts by weight of silicon dioxide (SiO2, particle diameter 40-100 ,um, pore volume 1.8 cm3/g, surface area 350 m2/g) in 1,700 parts by weight of n-heptane and a solution of 86 parts by weight of diethyl-aluminum chloride in 70 parts by weight of n-heptane.

The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing with n-heptane and drying under reduced pressure; it is employed in the second stage (1.2) Second stage of manufacture The solid-phase product obtained in stage (1.1) is suspended in 1,900 parts by weight of methanol whilst stirring and cooling to -20 C.

This suspension is combined with a solution of 51 parts by weight of VC13 in 2,000 parts by weight of methanol. The resulting suspension is stirred for 40 minutes at 250C and the solid-phase reaction product formed is then isolated by driving off the volatile constituents in a rotary evaporator which is brought to an operating pressure of 20 mm Hg and an operating temperature of 30"C. The analysis of the resulting product, i.e. of the vanadium-containing catalyst component (1), gives a vanadium content of 4.6 per cent by weight and a chlorine content of 13.5 per cent by weight.

Polymerization: 0.1 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.16 part by weight of isoprenyl-aluminum (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 9.5).

The Ziegler catalyst system thus obtained is introduced into a stirred autoclave which is charged with 80 parts by weight (cori:esponding to about 20 % of its capacity) of finely divided polyethylene. The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant value: ethylene pressure = 39.5 bars, hydrogen pressure = 2 bars, temperature = 100"C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 7 Manufacture of the vanadium-containing catalyst component (1): (1.1) First stage of manufacture The starting material is a suspension of 200 parts by weight of silicon dioxide (SiO2, particle diameter 40-148 jim pore volume 2.3 cm3/g, surface area 480 m2/g) in 1,700 parts by weight of n-heptane and a solution of 86 parts by weight of diethyl-aluminum chloride in 70 parts by weight of n-heptane.

The above solution is introduced into the above suspension at 20"C in the course of 60 minutes, whilst stirring, and the batch is then kept at 250C for a further 60 minutes, whilst stirring.

The solid-phase product is isolated from its suspension, obtained as above, by filtering off, washing with n-heptane and drying under reduced pressure; if it is employed in the second stage (1.2).

(1.2) Second stage of manufacture The solid-phase product obtained in stage (1.1) is suspended in 1,900 parts by weight of methanol whilst stirring and cooling to -20 C.

This suspension is combined with a solution of 55 parts by weight of VC13 in 1,800 parts by weight of methanol. The resulting suspension is stirred for 30 minutes at 250C and the solid-phase reaction product formed is then isolated by driving off the volatile constituents in a rotary evaporator which is brought to an operating pressure of 20 mm Hg and an operating temperature of 30"C. The analysis of the resulting product, i.e. of the vanadium-containing catalyst component (1), gives a vanadium content of 4.7 per cent by weight and a chlorine content of 12.4 per cent by weight.

Polymerization: 0.06 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.24 part by weight of isoprenyl-aluminum (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1:23).

The polymerization is then carried out for a period of 2 hours whilst stirring, with the following parameters, each of which is regulated to a constant value: ethylene pressure = 29.5 bars, hydrogen pressure = 2 bars, temperature = 95"C; the polymerization is then stopped by letting down the autoclave.

Further details of the product are to be found in the Table below.

EXAMPLE 8 The vanadium-containing catalyst component (1) is manufactured as described in Example 7.

Polymerization: 0.019 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.24 part by weight of isoprenyl-aluminum (2) as well as 0.025 part by weight of benzyl chloride (C7H7CI) (3) are added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 74 and a molar ratio of catalyst component (3) to metal Me (Me = aluminum) from catalyst component (2) of about 1: 6.5).

Further details of the product are to be found in the Table below.

EXAMPLE 9 The vanadium-containing catalyst component (1) is manufactured as described in Example 7.

Polymerization: 0.059 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.2 part by weight of Al(C2H5)3 (2) is added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 32).

Further details of the product are to be found in the Table below.

EXAMPLE 10 The vanadium-containing catalyst component (1) is manufactured as described in Example 7.

Polymerization: 0.033 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.2 part by weight of Al(C2H5)3 (2) as well as 0.025 part by weight of benzal chloride (C7H6C12) (3) are added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 58 and a molar ratio of catalyst component (3) to metal Me (Me = aluminum) from catalyst component (2) of about 1: 11).

Further details of the product are to be found in the Table below.

EXAMPLE 11 The vanadium-containing catalyst component (1) is manufactured as described in Example 7.

Polymerization: 0.023 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.2 part by weight of Al(C2H5)3 (2) as well as 0.025 part by weight of benzyl chloride (C7H7C1) (3) are added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1: 83 and a molar ratio of catalyst component (3) to metal Me (Me = aluminum) from catalyst component (2) of about 1 : 8.9).

Further details of the product are to be found in the Table below.

EXAMPLE 12 The vanadium-containing catalyst component (1) is manufactured as described in Example 7.

Polymerization: 0.017 part by weight of the vanadium-containing catalyst component (1) is suspended in 10 parts by weight of heptane and 0.2 part by weight of Al(C2H5)3 (2) as well as 0.038 part by weight of benzyl chloride (C7H7C1) (3) are added (the amounts correspond to an atomic ratio of vanadium from catalyst component (1) to metal (Me = aluminum) from catalyst component (2) of about 1:112 and a molar ratio of catalyst component (3) to metal Me (Me = aluminum) from catalyst component (2) of about 1: 5.8).

Further details of the product are to be found in the Table below.

Example Yield of Grams of polyethylene per Tap density Melt index Residual polyethylene gram of gram of g/1 MI2-16 chlorine parts by weight catalyst vanadium g/10 min. in the component (1) polymer ppm*) 1 235 5,340 121,000 300 1.4 26 2 290 2,900 66,000 500 7.1 49 3 215 3,900 87,000 310 4.8 38 4 280 2,800 67,000 510 7.5 50 5 300 3,500 99,000 470 19 37 6 310 3,100 67,000 515 8.3 44 7 280 4,700 99,000 300 5.5 26 8 180 9,470 201,000 280 9.5 13 9 170 2,880 61,000 280 5.7 43 10 150 4,550 97,000 290 8.3 27 11 180 7,800 167,000 350 13.1 16 12 180 10,600 225,000 330 14.2 12 *) calculated from the productivity and the chlorine content of the catalyst.

Claims

WHAT WE CLAIM IS:

1. A process for the manufacture of a homopolymer of an a-monoolefin of 2 to 6 carbon atoms of a copolymer of two or more such a-monoolefins by polymerizing the monomer or monomers at from 30 to 2000C and from 0.1 to 200 bars by means of a Ziegler catalyst system comprising (1) a vanadium-containing catalyst component, (2) a metal compound of the general formula MeRm-nXn where Me is aluminum, magnesium or zinc, R is a hydrocarbon radical of 1 to 12 carbon atoms, X is chlorine, bromine and/or hydrogen, m is the valency of the metal Me and n is a number from 0 to m-1, with or without (3) a halohydrocarbon of 1 to 12 carbon atoms, with the provisos that the atomic ratio of vanadium from catalyst component (1) to metal (Me) from catalyst component (2) is from 1: 0.1 to 1: 400 and, where component (3) is present, the molar ratio of catalyst component (3) to metal (Me) from catalyst component (2) is from 1: 0.1 to 1: 60, in which process the vanadium-containing catalyst component (1) employed is the solid-phase product (VI) which has been obtained by first (1.1) bringing into contact with one another (1.1.1) a finely divided, porous, inorganic oxidic material (I), which has a particle diameter of from 1 to 1,000 jim, a pore volume of from 0.3 to 3 cm3/g and a surface area of from 100 to 1,000 m2/g and has the formula SiO2.aAl203, where a is a number from 0 to 2, and (1.1.2) an aluminum compound (II) of the general formula AlR'3-pYp where R' is a hydrocarbon radical of 1 to 12 carbon atoms, Y is chlorine, bromine, hydrogen and/or OR", R" is a hydrocarbon radical of 1 to 12 carbon atoms, and p is a number from 0 to 3, the aluminum compound being dissolved in an organic solvent, so as to form a solid-phase product (III), with proviso that the weight ratio of inorganic oxidic material (I) employed to aluminum compound (II) employed is from 1: 0.05 to 1: 10, and then (1.2) bringing into contact with one another (1.2.1) the solid-phase product (III) obtained in stage (1.1) and (1.2.2) a solution (IV) obtained on bringing together 100 parts by weight of an alcohol (IVa) of the general formula Z-OH, where Z is a saturated hydrocarbon radical of 1 to 8 carbon atoms, and from 0.02 to 5 parts by weight (calculated as vanadium) of a vanadium trihalide (IVb), where halogen is chlorine and/or bromine, to form a dispersion (V), with the proviso that the weight ratio of solid-phase product (III, calculated as inorganic oxidic material I) to vanadium in the vanadium trihalide (IVb) is from 1: 0.01 to 1: 0.2, and then evaporating the dispersion (V) at below 200"C and above the melting point of the alcohol (IVa) employed, until a dry consistency is reached, i.e. the solid product (VI) is formed.

2. A process as claimed in claim 1, wherein the inorganic oxidic material (I) has a particle diameter of from 1 to 400,am, a pore volume of from 1 to 2.5 cm3/g and a surface area of from 200 to 500 m2/g.

3. A process as claimed in claim 1 or 2, wherein the inorganic oxidic material (I) has the formula SiO2.aAl203 where a is a number from 0 to 0.5.

4. A process as claimed in any of claims 1 to 3, wherein the aluminum compound (II) has the formula AlR'3-pYp, wherein R' is alkyl of 1 to 8 carbon atoms, Y is chlorine, hydrogen or OR", R" being alkyl of 1 to 8 carbon atoms, and p is a number from 0 to 2.

5. A process as claimed in any of claims 1 to 4, wherein the weight ratio of inorganic oxidic material (I) to aluminum compound (II) in stage (1.1) is from 1: 0.2 to 1: 3.

6. A process as claimed in any of claims 1 to 5, wherein the alcohol (IVa) is an alkanol of 1 to 4 carbon atoms and the vanadium trihalide( IVb) is a vanadium trichloride.

7. A process as claimed in any of claims 1 to 6, wherein the weight ratio of solid-phase product (III, calculated as inorganic oxidic material I) to vanadium in the vanadium trihalide (IVb) is from 1: 0.03 to 1: 0.15.

8. A process as claimed in any of claims 1 to 7, wherein the evaporation of the dispersion (V) is conducted at below 1200C.

9. A process as claimed in any of claims 1 to 8, wherein the metal compound (2) has the formula AlR3-mXn, where R is alkyl of 2 to 8 carbon atoms, X is chlorine or hydrogen and n is 0 or 1, and the atomic ratio of vanadium from catalyst component (1) to aluminum from catalyst component (2) is from 1: 4 to 1: 200.

10. A process as claimed in any of claims 1 to 9, wherein a halohydrocarbon (3) is present and the molar ratio of the halohydrocarbon to metal (Me) from catalyst component (2) is from 1:1 to 1: 25.

11. A process as claimed in any of claims 1 to 10, carried out as a dry-phase polymerization process.

12. A process as claimed in any of claims 1 to 11, wherein polymerization is carried out in the presence of hydrogen as molecular weight regulator.

13. A process as claimed in any of claims 1 to 12, wherein ethylene is homopolymerized.

14. A process as claimed in claim 1 carried out with a Ziegler catalyst system produced by a process substantially as described in any of the foregoing Examples.

15. A Ziegler catalyst system for use in the polymerization a-monoolefins and as defined in any of claims 1 to 10.

16. A vanadium-containing catalyst component for a Ziegler catalyst system as defined in any of claims 1 to 8.