GB1601418A

GB1601418A - Manufacture of homopolymers and copolymrs of a-monoolefins and catalysts and catalyst components therefor

Info

Publication number: GB1601418A
Application number: GB18635/78A
Authority: GB
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1977-05-11
Filing date: 1978-05-10
Publication date: 1981-10-28
Also published as: DE2721058C2; ATA338278A; IT7822987A0; DE2721058A1; BE866957A; AT360756B; IT1096265B; FR2390456A1

Description

(54) MANUFACTURE OF HOMOPOLYMERS AND COPOLYMERS OF a-MONOOLEFINS AND CATALYSTS AND CATALYST COMPONENTS THEREFOR (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 or copolymer of one or more a-monoolefins of 2 to 6 carbon atoms by polymerizing the monomer or monomers at from 30 to 2000C under a pressure of from 0.1 to 200 bars by means of a Ziegler catalyst system comprising (1) a titanium-containing catalyst component and (2) a metal compound of the general formula Me Am~n X where Me is the metal aluminum. magnesium or zinc, preferably aluminum, A is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms, preferably alkyl of 2 to 8 carbon atoms, X is chlorine, bromine, iodine or hydrogen, preferably chlorine 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, and especially 0, the atomic ratio of titanium from the catalyst component (1) to metal (Me) from the catalyst component (2) being from 1:0.1 to 1:500, preferably from 1:0.2 to 1:200. It also relates to a catalyst and a catalyst component for use therein.

Processes of this type have proved valuable in industry, but still suffer from a number of minor or major shortcomings. For example, the titanium-containing catalyst component (1) employed entails certain disadvantages. This applies even to those titanium-containing catalyst components which are prepared starting from a finely divided carrier. It is known that these supported catalysts are generally to be preferred to other titanium-containing catalyst components. since they both permit satisfactory operation and give a good result.

However, this advantage must be seen against the disadvantage that the conventional supported catalysts of the type in question present certain handling hazards and cause relatively severe pollution of the environment.

The present invention seeks to provide a titanium-containing catalyst component (1) which can be prepared starting from a finelv divided carrier but suffers from the above disadvantages to a substantially lesser extent, if at all, and can in addition confer advantages in operation and in the results obtained. for example can result in the polymer being formed in a specific yield which is not only high but is also constant with time, and can give a polymer which has particularly advantageous morphological properties, eg. a high bulk density and good free-flowing properties.

The present invention is based on the use of a titanium-containing catalyst component (1) which is obtained by bringing a finely divided silicon oxide carrier (I) of a certain type into contact with a solution (II) which is obtained from an alcohol of a certain type, a titanium trihalide and a magnesium compound of a certain type, isolating a solid-phase intermediate (IV) by evaporating the resulting dispersion (III), and bringing this intermediate into contact with a solution of a metal compound (V) of a certain type, so as again to form a dispersion, in which the dispersed solid-phase product (VI) is the novel titanium-containing catalyst component (1).

Accordingly, the present invention provides a process for the manufacture of a homopolymer or copolymer of one or more a-monoolefins of 2 to 6 carbon atoms by polymerizing the monomer or monomers at from 30 to 200"C under a pressure of from 0.1 to 200 bars by means of a Ziegler catalyst system comprising (1) a titanium-containing catalyst component and (2) a metal compound of the general formula Me Am~n Xn where Me is the metal aluminum, magnesium or zinc, preferably aluminum, A is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms, preferably alkyl of 2 to 8 carbon atoms, X is chlorine, bromine, iodine or hydrogen, preferably chlorine 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, and especially 0, the atomic ratio of titanium from the catalyst component (1) to metal (Me) from the catalyst component (2) being from 1:0.1 to 1:500, preferably from 1:0.2 to 1:200, wherein the titanium-containing catalyst component (1) employed is the solid-phase product (VI) which is obtained by (1.1) initially bringing into contact (1.1.1) a finely divided, porous, inorganic oxidic material (I), which has a particle diameter of from 1 to 1,000 Fm, preferably from 1 to 400 llm, a pore volume of from 0.3 to 3 cm3/g, preferably from 1 to 2.5 cm3/g. and a surface area of from 100 to 1,1000 m2/g, preferably from 200 to 400 m2/g. and has the formula SiO2.aAl2O3, where a is a number from 0 to 2, especially from 0 to 0.5, and (1.1.2) a solution (II) obtained by bringing together (IIa) 100 parts by weight of an alcohol of the general formula Z-OH where Z is a saturated hydrocarbon radical of 1 to 8 carbon atoms, especially a saturated hydrocarbon radical of 1 to 6 carbon atoms, and preferably alkyl of 1 to 4 carbon atoms, (IIb) from 0.01 to 6, preferably from 0.04 to 3.5, parts by weight (calculated as titanium) of a titanium trihalide, where halogen is chlorine and/or bromine, preferably a titanium trichloride. and (IIc) from 0.01 to 4, preferably from 0.04 to 2.5, parts by weight (calculated as magnesium) of a magnesium compound which is soluble in the alcohol (IIa), especially a compound which contains halogen and/or carbon and preferably a compound which contains both chlorine and carbon, to form a dispersion (III), the weight ratio of inorganic oxidic material (I) to titanium in the titanium trihalide (IIb) being from 1:0.01 to 1:0.2, preferably from 1:0.03 to 1:0.15, and the weight ratio of inorganic oxidic material (I) to magnesium in the magnesium compound (IIc) being from 1:0.01 to 1:0.25, preferably from 1:0.03 to 1:0.15. the dispersion (III) is evaporated to dryness at below 200, preferably below 1600C, but above the melting point of the alcohol (IIa) employed, to form a solid-phase intermediate (IV), and (1:2) thereafter (1.2.1) the solid-phase intermediate (IV) obtained from stage (1.1) and (1.2.2) a metal compound (V) of the general formula Mt Gs~t Et where Mt is aluminum or silicon, preferably aluminum, G is a hydrocarbon radical of 1 to 12 carbon atoms, especially alkyl of 1 to 12 carbon atoms, preferably alkyl of 2 to 8 carbon atoms, E is chlorine. bromine, iodine, hydrogen or -OD, preferably chlorine or hydrogen, D 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, s is the valency of Mt and t is a number from 0 to s-l, preferably from 1 to 2, it Mt is aluminum, or from 0 to 4, prferably from 1 to 4, if Mt is silicon, dissolved in an organic solvent, are brought into contact to form a dispersion, the weight ratio of solid-phase intermediate (IV) to metal compound (V) being from 1:0.05 to 1:2, preferably from 1:0.1 to 1:1. the solid-phase product (VI) in the resulting dispersion being the titanium-containing catalyst component (1).

A process for the manufacture of a homopolymer or copolymer of an a-monolefin by means of a ziegler catalyst of which the titanium-containing component has been made by a method up to and including stage (1.1) defined above, and the catalyst therefore, are described and claimed in the specification of our copending British patent application no.

4168/77 (Serial No 1,565,572).

The present invention also provides the catalyst component (1) and the Ziegler catalyst system (1) + (2) as defined above as novel compositions.

In relation to comparable conventional processes, a process within the present invention is distinguished by the fact that, for example, it provides technical and economic improvements. Thus, the manufacture of the catalyst component (1) is relatively simple and since it furthermore does not require the use of an excess of the titanium compound, whilst in conventional methods such excess is necessary, there is also a substantial improvement in respect of economy and less pollution of the environment. In addition, the process permits the use of constant production conditions, since the novel catalyst system exhibits a remarkable constancy in specific yield both from batch to batch and over a period of time.

Furthermore, when polymerizing olefins by means of the present catalyst system, a substantial advantage can be derived from the fact that these catalyst systems give a relatively high productivity (calculated as the amount by weight of polymer per unit weight of titanium) and a low halogen content. The polymer then contains so little of the inherently undesirable catalyst constituents (titanium and halogen) that these no longer interfere and their removal, which would require a separate process step, is superfluous. Furthermore, polymers obtainable by a process within the invention exhibit further advantageous properties: for example, their morphology conforms to an important range of requirements. The content of dust-like polymer particles is very low, thereby greatly reducing the dust explosion hazard; in addition, the shape of the particles is such that not only can the material be stirred easily (which is important in the manufacture of the polymer) but is also has a high bulk density and good free-flowing characteristics, both of which are advantages in the handling of the polymers.

The following details may be noted with respect to the process of the invention: The polymerization process as such can, provided due attention is given to the characterizing features, be carried out in virtually all relevant conventional technical embodiments. eg. as a batchwise, cyclic or continuous process, which may be, for example, a suspension polymerization, solution polymerization or dry-phase polymerization process.

The said embodiments, ie. the embodiments of Ziegler olefin polymerization, are well-known from the literature and from industrial practice and do not require more detailed comment here. However, it may be noted that the titanium-containing catalyst component (1), like corresponding conventional catayst components, can, for example, be brought together with the catalyst component (2) either outside or inside the polymerization vessel; in the latter case, this may be done, for example, by spatially. separate introduction of the components, which may be handled in the form of a suspension (catalyst component (1)) or a 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 wax-coated particles; this method can be of adantage in dry-phase polymerization processes.

The following may be noted with respect to the titanium containing catalyst component (l) per se: The component is prepared in two stages, referred to both above and in the remainder of the specification as (1.1) and (1.2).

In stage (1.1), a finely divided inorganic oxidic material (I) of the type defined above and a particular solution (ill) defined above are brought into contact, whereby a dispersion (III) is formed, which is evaporated to dryness, so as to form a solid-phase intermediate (IV). In stage (1.2), the latter is brought into contact with a solution of a particular metal compound (V). defined above, so as again to form a dispersion, in which the dispersed solid-phase product (VI) is the novel catalyst component (1).

Specifically, the following procedure may be employed: Stage (1.1) The inorganic oxidic material (I), undiluted or dispersed in an alcohol (advantageously an alcohol as defined under (IIa), the dispersion having a solids content of not less than 5 per cent by weight), is combined with the solution (II). It is advantageous if, after combination, the batch is kept at from 10 to 160 Cn especially from 20 to 1200C, for from 5 to 120 minutes, especially from 20 to 90 minutes, and the resulting dispersion (III) is only then evaporated.

The solution (II) itself can be prepared by conventional methods and does not entail any special features. An advantageous method has proved to be to prepare the solution (II) by combining a solution of the alcohol (IIa) and the titanium trihalide (IIb) with a solution of the alcohol (IIa) and the magnesium compound (IIc).

As the final measure in stage (1.1), the dispersion (III) is evaporated to dryness, giving the solid-phase intermediate (IV). This can be done by conventional methods of gently evaporating dispersions, provided the above temperature conditions are observed. This means that it is generally advantageous, and in the case of relatively high alcohols (IIa) at times essential, to carry out the evaporation under reduced pressure, the degree of reduction depending on circumstances. As a rule of thumb, the combination of temperature and pressure should be such that the evaporation is complete after from about 1 to 10 hours.

It is also advantageous to carry out the evaporation under conditions which constantly keep the treated material homogeneous; rotary evaporators, for example, have proved suitable for this purpose. Some residual alcohol, for example bound as a complex, is generally not detrimental to the solid-phase intermediate (IV).

Stage (1.2) Suitably, a suspension of from 1 to 20, preferably about 10, per cent strength by weight of the solid-phase intermediate (IV), and a solution of from 5 to 80, preferably about 10, per cent strength by weight of the metal compound (V) are first prepared in separate batches, suitable suspending media or solvents being, in particular, hydrocarbons, especially relatively low-boiling alkane hydrocarbons, eg. hexanes, heptanes or gasolines. The suspension and the solution are then combined in the amounts which give the desired weight ratio. In general, they are combined by introducing the solution into the suspension, whilst stirring, since this procedure is more practical than the converse, though the latter is also feasible. At from -25 to 120 C, especially from 25 to 80 C, the formation of the dispersed solid-phase product (VI) is complete in the course of from 15 to 600 minutes, especially from 60 to 300 minutes. This product can advantageously be used directly in the especiallv from 60 to 300 minutes. This product can advantageously be used directly, in the form of the resulting dispersion, with or without washing by digestion, as the titanium containing catalyst component (1). However, if desired it is also possible to isolate the solid-phase product (VI) and only then to employ it as the catalyst component (1); in that case, a suitable method of isolation is. for example, to separate the product (VI) from the liquid phase by filtration, wash it with pure liquid (for example of the type which has been used as the suspending medium or solvent), and dry it, for example under reduced pressure.

The new titanium-containing catalyst components (1), ie. the solid-phase product (VI), can be employed, within the process defined above, for the manufacture of the polymers mentioned above, in the way in which titanium-containing compounds are conventionally employed in the Ziegler polymerization of olefins. To this extent, the process of the invention exhibits no peculiar features. and reference may be made to the methods of use of the catalvsts which are well-known from literature and from practice. It only remains to be mentioned that the process is particularly suitable for the manufacture of ethylene homopolymers and that in the case of the manufacture of copolymers of ethylene with higher α-monoolefins, or the manufacture of homopolymers of higher α-monoolefins, suitable α-monoolefins are especially propene, 1-butene, 4-methyl-1-pentene and 1 hexene. The molecular weight of the polymers can be regulated in the relevant conventional manner, especially by means of hydrogen as the regulator.

As regards the material concerned in the new titanium-containing catalyst component (1), the following details should be noted: The inorganic oxidic material (1) to be employed in stage (1:1) is in general an alumosilicate or in particular a silica; it is important that the material should have the required properties and should be as dry as possible (no weight loss after 6 hours at 160 C under a pressure of 2 mm hg). Particularly suitable inorganic oxidic materials @r@ th@@ obtained according obtained according to the first stage of the process described in German Laid-Open Application DOS 2,411,735, especially when hydrogels obtained by the process described ny wich hydrogen obtained by the process described in british Patent Specification 1,368,711 are used as starting materials.

Examples of alcohols (IIa) to be employed are methanol, ethanol, propanols and butanols. Particularly suitable alcohols have proved to be methanol, ethanol, isopropanol and n-butanol. The alcohols (IIa) can be employed in the form of individual compounds or of mixtures of two or more such compounds.

The titanium trihalide (IIb) empolyed be a titanium trihalide conventionally used in Ziegler catalyst systems, for examples a reaction product obtained by reducting a titanium tetrahalide with hydrogen, aluminium or a organic-aluminium compound. Particularly suitable compounds have proved to be trichlorides of the formula TiCl3, as obtained on reducing titanium tetrachloride by means of hydrogen, as well as trichlorides of the formula TiCl3.1/3 AlCl3, as obtained on reducing titanium tetrachloride with metallic aluminium. The titanium trihalides can be employed in the form individual compounds or of mixtures of two or more of these.

The magnesium compounds (IIc) also employed in stage (1.1) can advantageously be a compounds from the following categories of magnesium compounds.

(A) Magnesium compounds of the general formula Mg(OR')2 where R' is a hydrogen radical of 1 to 10 carbon atoms, especially alkyl of 1 to 6 carbon atoms.

Examples of very suitable compounds are: magnesium methylate, ethylate, n-propylate, 1-propylate, cyclohexylate and phenol ate.

Magnesium ethylate and magnesium n-propylate are particularly suitable.

(B) Complex alkoxides of magnesium with other metals Examples of very suitable compounds are the complex alkoxides of the formula MgiAl(OC2Hs)4]2, Mg3[Al(OC2H5)6j2, Li2[Mg(OC3H7)4], Mg[Ti(OC3H7)6] and MgLB(OC2Hs)412 (C) Magnesium halides of the general formula MgZ2, where Z is chlorine, bromine or iodine, especially chlorine or bromine.

Examples of very suitable compounds are magnesium chloride and magnesium bromide.

(D) Complexes of the magnesium halides listed under (C) with alcohols of 1 to 6 carbon atoms, especially alkanols of 1 to 6 carbon atoms.

Amongst these, particularly suitable compounds are the complexes of the formulae MgCl2.6C2H5OH and MgCI2.4CH3OH.

(E) Magnesim halide compounds of the general formula MgZ(OR'), where Z is as defined under (C) and R' is as defined under (A).

A particularly suitable compound of this type has the formula MgCl(OC2H5).

(F) The carriers, containing chemically bound magnesium, which characterize the subject matter of British Patent Specification 1,380,949, especially manasseite (formula: Mg6.Al2.(OH)16.CO3.4H2O), which has been brought to a chlorine content of from 50 to 75 per cent by weight by halogenation.

The magnesium compounds (IIc) can be employed in the form of individual compounds or of mixtures of two or more such compounds; these can of course also be compounds which are formed in situ when preparing the solution (II).

For the purposes of the present invention, preferred magnesium compounds are those of classes A. C and D and especially F.

The metal compound (V) to be employed in stage (1.2) can advantageously to a compound from one of the following two classes: Aluminum compounds as represented by the formulae Al(C2H5)3, Al(C2H5)2Cl, Al(C2H5)2Br, Al(C2H5)1 5Cl1 -5, Al(C2H5)1.5Br1 ., Al(C2H5)Cl2, Al(C2H5)Br2, Al(C4H9)3, Al(C4H9)2Cl, Al(C4H9)Cl2, Al(C2H5)2H, Al(C4H9)2H, Al(C3H7)2(OC3H7) and Al(C2H5)1.5(OC2H5)1.5.

Silicon compounds, as represented by the formulae SiCl4, SiBr4, Si(CH3)2Cl2, Si(CH3)3Cl, SiHCl3, Si(C2H5)3H, Si(OC2H5)4 and Si(OC6H5)4.

Particularly suitable aluminium compounds are Al(C2H5)2Cl, Al(C2H5)1.5Cl1.5, Al(C2H5)Cl2 and Al(C2H5)2H.

Particularly suitable silicon compounds are SiCI4, Si(CH3)3CI, Si(C2H5)3CI and Si(C2H5)3H.

The metal compounds (V) can be employed in the form of individual compounds or of mixtures of two or more such compounds.

The relevant conventional compounds may be used as the catalyst component (2); examples of suitable compounds are Al(C2H5)3, Al(i-C4H9)3, Al(n-C4H9)3, Al(C8H17)3 and isoprenylaluminum.

In conclusion, it should be noted that the titanium-containing catalyst components (1) according to the invention, ie. the products (VI), are sensitive to hydrolysis and oxidation.

To this extent. these substances should therefore be handled with the precautionary measures conventionally used for Ziegler catalysts (for example exclusion of moisture, and the use of an inert gas atmosphere).

Example 1 Preparation of the titanium-containing catalyst component (1): Stage (1.1) The starting material is a suspension of 1,000 parts by weight of silica (SiO2, particle diameter 40-150 m, pore volume 2.1 cm /g, surface area 330 m/g) in 3,000 parts by weight of methanol. This suspension is combined with a solution of 163 parts by weight of TiCl3.1/3 AlCl3 and 250 parts by weight of manasseite (Mg6.Al2.(OH)16.CO34H2O), which has been brought to a chlorine content of 72 per cent by weight by halogenation with phosgen, in 4,000 parts by weight of methanol. The resulting suspension is stirred for 60 minutes at 400C and the resulting solid-phase intermediate (IV) is then isolated by removing the volatile constituents in a rotary evaporator which is brought down to an operating pressure of 20 mm Hg, and up to an operating temperature of 85 C. The analysis of the resulting intermediate (IV) indicates a titanium content of of 3.32 per cent by weight and a chlorine content of 11.71 per cent by weight.

Stage (1.2) 10 parts by weight of the solid-phase intermediate (IV) obtained in stage (1.1) are suspended in 50 parts by weight of heptane, a solution of 2.5 parts by weight of diethyl-aluminium chloride in 20 parts by weight of heptane is then added to this suspension at 50 C, and the batch is stirred for 2 hours at 50 C. It is then filtered and the product is washed three times heptane, and dried under reduced pressure. Analysis of the resulting solid-phase product (VI), ie. of the titanium-containing catalyst component (1), indicates a titanium content of 1.84 per cent by weight.

Polymerization: 0.310 part by weight of the titanium-containing catalyst component (1) is suspended in 20 parts by weight of heptane and 2.5 parts by weight of Al (C2H5)3 (2) are added.

The resulting Ziegler catalyst system is introduced into a stirred autoclave which is charged with 8,000 parts bv weight of isobutane (corresponding to about 50cue of the capacity of the autoclave). Polymerization is then carried out for 2 hours whilst stirring, at an ethylene pressure of 20 bars. hydrogen pressure of 5 bars and temperature of 90"C, these parameters being kept constant by a control system. The polymerization is then stopped by letting down the autoclave.

Details of the product obtained may be found in the Table below.

Example 2 The procedure described in Example 1 is followed, except that in preparing the titanium-containing catalyst component (1), the diethyl-aluminum chloride in stage (1.2) is replaced by the same amount by weight of ethyl-aluminum dichloride.

The resulting catalyst component (1) contains 1.2 per cent by weight of titanium: it is employed in the polymerization in an amount of 0.340 part by weight.

Details of the polymer obtained are to be found in the Table below.

Example 3 The procedure described in Example 1 is followed, except that in preparing the titanium-containing catalyst component (1) in stage (1.2), the following method is used: 10 parts by weight of the solid-phase intermediate (IV) obtained in stage (1.1) are suspended in 35 parts by weight of heptane, a solution of 5 parts by weight of tetrachlorosilane in 35 parts by weight of heptane is added to this suspension at 80"C and the batch is stirred for 2 hours at the boil. It is then filtered, washed three times with heptane and dried under reduced pressure.

The resulting catalyst component (1) contains 1.75 per cent by weight of titanium: it is employed in the polymerization in an amount of 0.340 part by weight.

Details of the polymer obtained are to be found in the Table below.

Example 4 The procedure described in Example 1 is followed except that in preparing the titanium-containing catalyst component (1) in stage (1.2), the following method is used: 10 parts by weight of the solid-phase intermediate (IV) obtained in stage (1.1) are suspended in 35 parts by weight of heptane, a solution of 5 parts by weight of trimethylchlorosilane in 35 parts by weight of heptane is added to this suspension at 50"C and the batch is stirred for 2 hours at the boil. It is then filtered, washed three times with heptane and dried under reduced pressure.

The resulting catalyst component (1) contains 1.93 per cent by weight of titanium: it is employed in the polymerization in an amount of 0.335 part by weight.

Details of the polymer obtained are also to be found in the Table below.

Example 5 Preparation of the titanium-containing catalyst component (1): Stage (1.1) The starting material is a suspension of 1,000 parts by weight of silica (SiO. particle diameter 40-150 um, pore volume 2.1 cm3/g, surface area 330 m-/g) in 800 parts by weight of ethanol. This suspension is combined with a solution of 163 parts by weight of Tics3.' AICl3 and 265 parts by weight of manasseite (Mg6.All.(OH)l,.CO.4H.O). which has been brought to a chlorine content of 72 per cent by weight by halogenation with phosgene. in A.()f)() parts by weight of ethanol. The resulting suspension is stirred for 60 minutes at 40'C and the resulting solid-phase intermediate (IV) is then isolated by removing the volatile constituents in a rotary evaporator which is brought down to an operating pressure of 3l) mm Hg, and up to an operating temperature of 8() C. Analysis of the resulting intermediate (IV) indicates a titanium content of 2.46 per cent by weight.

Stage (1.2) 14.4 parts by weight of the solid-phase intermediate (IV) obtained in stage (1.1) are suspended in 340 parts by weight of heptane. a solution of 7 parts by weight of diethvlaluminum chloride in 70 parts bv weight of heptane is then added to this suspension at 30 C. and the batch is stirred for 2 hours at 50 C. It is then filtered and the product is washed three times with heptane, and dried under reduced pressure. Analysis of the resulting solid-phase product (VI), ie. of the titanium-containing catalyst component (1), indicates a titanium content of 2.3 per cent by weight and a content of 16.7 per cent by weight.

Polymerization: 0.51 part by weight of the titanium-containing catalyst component (1) is suspended in 20 parts by weight of heptane and 3.3 parts by weight of Al(C2H5)3 (2) are added.

The resulting Ziegler catalyst system is introduced into a stirred autoclave which is charged with 4,000 parts by weight of isobutane (corresponding to about 50% of the capacity of the autoclave). Polymerization is then carried out for 2 hours whilst stirring, at an ethylene pressure of 15 bars, hydrogen pressure of 5 bars and temperature of 100"C, these parameters being kept constant by a control system. The polymerization is then stopped bv letting down the autoclave.

Details of the product obtained may be found in the Table below.

Example 6 Preparation of the titanium-containing catalyst component (1): Stage (1.1) The starting material is 1.500 parts by weight of silica (SiO2, particle diameter 40-150 iim, pore volume 2.1 cm3/g, surface area 330 m-/g). This silica is combined with a solution of 1,630 parts by weight of TiC13.1/3 AICl3 and 2,500 parts by weight of manasseite (Mg6.Al.(OH)l6.CO3.4H2O), which has been brought to a chlorine content of 70 per cent by weight by halogenation with phosgene, in 4,000 parts by weight of methanol. The resulting suspension is stirred for 90 minutes at 80"C and the resulting solid-phase intermediate (IV) is then isolated by removing the volatile constituents in a rotary evaporator which is brought down to an operating pressure of 18 mm Hg, and up to an operating temperature of 81"C. Analysis of the resulting intermediate (IV) indicates a titanium content of 2.82 per cent by weight.

Stage (1.2) 500 parts by weight of the solid-phase intermediate (IV) obtained in stage (1.1) are suspended in 1.400 parts by weight of heptane. a solution of 138 parts by weight of diethvlaluminum chloride in 700 parts by weight of heptane is then added at 50"C, and the batch is stirred for 2 hours at 50"C. The supernatant heptane is then decanted off the solid and the latter is washed bv twice digesting with heptane and decanting, and is then dried under reduced pressure. Analysis of the resulting solid-phase product (VI), ie. of the titanium-containing catalyst component (1). indicates a titanium content of 2.55 per cent by weight.

Polymerization: 0.388 part by weight of the titanium-containing catalyst component (1) is suspended in 20 parts by weight of heptane and 3.3 parts by weight of Al(QH5)3 (2) are added.

The resulting Ziegler catalyst system is introduced into a stirred autoclave which has been charged with 4,000 parts by weight of isobutane (corresponding to about 50% of the capacity of the autoclave). Polymerization is then carried out for 2 hours whilst stirring, at an ethylene pressure of 15 bars. hydrogen pressure of 5 bars and temperature of 100"C, these parameters being kept constant by a control system. The polymerization is then stopped by letting down the autoclave.

Details of the product obtained may be found in the Table below.

Example 7 Preparation of the titanium-containing catalyst component (1): Stage (1.1) This is carried out as in Example 6.

Stage (1.') 500 parts by weight of the solid-phase intermediate (IV) obtained in stage (1.1) are suspended in 1,400 parts by weight of heptane, a solution of 75 parts by weight of ethylaluminum dichloride in 900 parts by weight of heptane is then added at 50"C, and the batch is stirred for 2 hours at 50"C. The supernatent heptane is then decanted off the solid and the latter is washed by twice digesting with heptane and decanting, and is then dried under reduced pressure. Analysis of the resulting solid-phase product (VI), ie. of the titanium-contaning catalyst component (1), indicates a titanium content of 1.89 per cent by weight.

Polymerization: 0.393 part by weight of the titanium-containing catalyst component (1) is suspended in 20 parts by weight of heptane and 3.3 parts by weight of Al(C2H5)3 (2) are added.

The resulting Ziegler catalyst system is introduced into a stirred autoclave which is charged with 4,000 parts by weight of isobutane (corresponding to about 50% of the capacity of the autoclave). Polymerization is then carried out for 2 hours whilst stirring, at an ethylene pressure of 15 bars, hydrogen pressure of 5 bars and temperature of 100 C, these parameters being kept constant by a control system. The polymerization is then stopped by letting down the autoclave.

Details of the product obtained may also be found in the Table below.

TABLE Example Yield of Grams of polyethylene per Bulk Pourability MI2.16 Cl in the polyethylene g of g of density (sec.) (g/10 min.) polymer (parts by catalyst titanium (gll) ppm by weight) 1 3,320 10,700 582,000 320 7.6 0.25 17 2 3,050 9,000 750,000 310 7.4 0.56 13 3 3,340 9,300 530,000 330 7.5 0.42 25 4 3,100 9,300 480,000 320 7.5 0.51 21 5 1,900 3,700 161,000 310 7.2 9.0 62 6 2,320 6,000 235,000 310 7.6 7.7 43 7 3,050 7,760 411,000 300 7.3 4.7 24 +) Apparent Density Test, ASTM D 1895-67, method A

Claims

WHAT WE CLAIM IS:

1. A process for the manufacture of a polymer of one or more a-monoolefins of 2 to 6 carbon atoms by polymerizing the monomer or monomers at from 30 to 2000C under a pressure of from 0.1 to 200 bars by means of a Ziegler catalyst system comprising (1) a titanium-containing catalyst component and (2) a metal compound of the general formula Me Amn Xn where Me is aluminum. magnesium or zinc, A is a hydrocarbon radical of 1 to 12 carbon atoms. X is chlorine, bromine, iodine or hydrogen, m is the valency of Me and N is a number from 0 to m-1, with the proviso that the atomic ratio of titanium from the catalyst component (1) to metal (Me) from the catalyst component (2) is from 1:0.1 to 1:500, wherein the titanium-containing catalyst component (1) employed is the solid-phase product (VI) which is obtained by (1.1) initially bringing into contact (1.1.1) a finely divided, porous inorganic oxidic material (I), which has a particle diameter of from 1 to 1.000cm. 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) a solution (II) obtained by bringing together (IIa) 100 parts by weight of an alcohol of the general formula Z-OH where Z is a saturated hydrocarbon radical of 1 to 8 carbon atoms, (IIb) from 0.01 to 6 parts by weight (calculated as titanium) of a titanium trihalide, wherein halogen is chlorine and/or bromine, and (IIc) from 0.01 to 4 parts by weight (calculated as magnesium) of a magnesium compound which is soluble in tile alcohol (IIa), to form a dispersion (III), with the proviso that the weight ratio of inorganic oxidic material (I) to titanium in the titanium trihalide (IIb) is from 1:0.01 to 1:0.2 and the weight ratio of inorganic oxidic material (I) to magnesium in the magnesium compound (IIc) is from 1:0.01 to 1:0.25, the dispersion is evaporated to dryness at below 200"C but above the melting point of the alcohol (aha) employed, to form a solid-phase intermediate (IV). and (1.2) thereafter (1.2.1) the solid-phase intermediate (IV) obtained from stage (1.1) and (1.2.2) a metal compound (V) of the general formula Mt Gs-t Et where Mt is aluminum or silicon, G is a hydrocarbon radical of 1 to 12 carbon atoms, E is chlorine, bromine, iodine, hydrogen or -OD, D is a hydrocarbon radical of 1 to 12 carbon atoms, s is the valency of Mt and t is a number from 0 to s-1 if Mt is aluminum or from 0 to 4 if Mt is silicon, dissolved in an organic solvent, are brought into contact to form a dispersion. with the proviso that the weight ratio of solid-phase intermediate (IV) to metal compound (V) is from 1:0.05 to 1:2, the solid-phase product (VI) in the resulting dispersion being the titanium-containing catalyst component (1).

2. A process as claimed in claim 1, wherein the oxidic material (I) has a particle diameter of from 1 to 400Rm, a pore volume of from 1 to 2.5 cm3/g and a surface area of from 200 to 400 m-/g and a in its formula is a number from 0 to 0.5.

3. A process as claimed in claim 1 or 2, wherein the alcohol (IIa) is an alkanol of 1 to 4 carbon atoms, the titanium trihalide (IIb) is a titanium trichloride and the magnesium compound (IIc) contains both chlorine and carbon.

4. A process as claimed in any of claims 1 to 3, wherein the solution (II) contains, per 100 parts by weight of alcohol (IIa), from 0.04 to 3.5 parts by weight of titanium compound (lib), calculated as titanium, and from 0.04 to 2.5 parts by weight of magnesium compound (IIc), calculated as magnesium.

5. A process as claimed in any of claims 1 to 4, wherein the dispersion (III) contains, per part by weight of oxidic material (I), from 0.03 to 0.15 parts by weight of titanium in (lib) and from 0.03 to 0.15 parts by weight of magnesium in (IIc) and the evaporation to dryness is conducted at below 1600C after the dispersion has been kept for from 5 to 120 minutes at from 10 to 1600C.

6. A process as claimed in any of claims 1 to 5, wherein the metal compound (V) is a C2-C,. alkyl aluminum chloride or hydride having 1 or 2 alkyl groups.

7. A process as claimed in any of claims 1 to 6, wherein the weight ratio of solid-phase intermediate (IV) to metal compound (V) is from 1:0.1 to 1:1.

8. A process as claimed in claim 1, wherein the titanium-containing catalyst component (1) has been obtained by a method substantially as described in any of the foregoing Examples 1 to 7.

9. A process as claimed in any of claims 1 to 8, wherein the catalyst component (2) is a C2-C8 trialkyl aluminum or a C2-C8 dialkylaluminum hydride or chloride, and the atomic ratio of titanium from the catalyst component (1) to aluminum from the catalyst component (2) is from 1:0.2 to 1:200.

10. A process as claimed in any of claims 1 to 9, wherein ethylene is homopolymerized.

11. A process for the manufacture of a polymer of one or more -monoolefins of 2 to 6 carbons atoms carried out substantially as described in any of the foregoing Examples.

12. Homopolymers and copolymers of a-monoolefins of 2 to 6 carbon atoms when manufactured by a process as claimed in any of claims 1 to 11.

13. A titanium-containing catalyst component for a Ziegler catalyst system when obtained by a method as defined in any of claims 1 to 8.

14. A Ziegler catalyst system for the polymerization of ot-monoolefins of 2 to 6 carbon atoms and as defined in any of claims 1 to 9.