Catalyst composition for polymerization of olefins and method for preparing the same

Abstract

The present invention relates to a catalyst composition for polymerization of olefins comprising: (a) a solid catalyst pre cursor comprising at least one vanadium compound, at least one magnesium compound and a polymeric material or a solid catalyst precursor comprising at least one vanadium compound, at least one further transition metal compound and/or at least one alcohol, at least one magnesium compound and a polymeric material; and (b) a cocatalyst comprising at least one aluminum compound; and to a method for preparing a catalyst composition according to the present invention, comprising the steps of: (a) combining the components of the solid catalyst precursor; and (b) activating the catalyst precursor with aluminum compound.

Description

FIELD OF THE INVENTION

[0001] This invention relates to catalyst compositions for polymerization of olefins and methods of preparing such catalyst compositions.

DESCRIPTION OF THE PRIOR ART

[0002] Several publications are referenced in this application. These references describe the state of the art to which this invention pertains, and are incorporated herein by reference.

[0003] The application of vanadium based Ziegler-Natta catalysts for industrial use has been limited to vanadium trichloride and vanadium oxytrichloride as homogenous catalysts in solution polymerization for the production of ethylene-propylene copolymers. To attain suitable activity for polymerization these catalysts require the use of halogenated organic molecules such as chloroform and trichlorofluoromethane as a promoter. In the absence of the promoter the catalyst activity is low. Further, the kinetic behavior of these catalysts during polymerization display high initial rates of polymerization followed by a sharp decrease with time, decay type rate-time kinetics, and as result produce resin of poor morphology.

[0004] The application of vanadium based catalysts for ethylene polymerization, high density and linear low density polyethylene production, has been comparatively very limited. Attempts have been made to support vanadium based catalysts on silica or magnesium chloride to produce catalysts for ethylene polymerization. U.S. Pat. No. 4,508,842 describes a catalyst preparation in which a complex of VCl3 and tetrahyrofuran (THF) is treated with silica, the solvent is then removed from the solid by distillation and a boron trihalide or alkylaluminum halide modifier is added to the solid. In addition, chloroform is used as a promoter with the catalyst for ethylene polymerization. However, the productivity and stability of this catalyst system is relatively poor.

[0005] U.S. Pat. Nos. 5,534,472 and 5,670,439 describe a silica supported vanadium catalyst prepared by the prior contacting of silica with an organomagnesium compound and a trialkylaluminum compound. The catalysts are suitable for the production of ethylene-hexene copolymer. However, the polymerizations are conducted with trichlorofluoromethane or dibromomethane promoters.

[0006] Further, procedures typically used for the preparation of suitable magnesium chloride and silica supports such as spray drying or re-crystallization processes are complicated and expensive. Also, the inorganic supports remain in the product, which can affect the product properties, such as optical properties, or processing.

[0007] It is an object of the present invention to provide a catalyst composition which overcomes the drawbacks of the prior art, especially providing a catalyst composition which is cheap in preparation and which exhibits an enhanced productivity, stability and activity without using halogenated organic molecules as a promoter. Moreover, it is a further object to provide a method for preparing such a catalyst composition.

SUMMARU OF THE INVENTION

[0008] The present invention provides a catalyst composition for polymerization of olefins comprising: (a) a solid catalyst precursor comprising at least one vanadium compound, at least one magnesium compound and a polymeric material; and (b) a cocatalyst comprising at least one aluminum compound for activating the catalyst precursor.

[0009] Most preferably, the component (a) further comprises at least one further transition metal compound and/or at least one alcohol.

[0010] The polymer particles used in catalyst preparation have a mean particle diameter of about 5 to 1 000 microns and a pore volume of at least about 0.05 cm3/g and a pore diameter of about 20 to 10 000 angstroms, preferably from about 500 to 10 000 angstroms, and a surface area of about 0.1 m2/g to 100 m2/g, preferably from about 0.2 m2/g to 30 m2/g.

[0011] The catalyst composition of the present invention may be used for polymerization of olefins, such as ethylene forming polyethylene homopolymer, and ethylene with higher olefins forming copolymers.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The solid catalyst precursor used in the present invention comprises preferably at least one vanadium compound, at least one transition metal compound and/or at least one alcohol, at least one magnesium compound and a polymeric material having a mean particle diameter of about 5 to 1 000 microns and a pore volume of at least about 0.05 cm3/g and a pore diameter of about 20 to 10 000 angstroms, preferably from about 500 to 10 000 angstroms, and a surface area of about 0.1 m2/g to 100 m2/g, preferably from about 0.2 m2/g to 30 m2/g.

[0013] The vanadium compound used for the synthesis of the solid catalyst precursor in the present invention is represented by the general formulas V(OR1)nX4−n, V(R2)nX4−n, VX3 and VOX3, wherein R1 and R2 represent an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms, X represents a halogen and n represents a number satisfying 0≦n≦4. Examples of R1 and R2 include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl and the like

[0014] Preferred examples of the above mentioned vanadium compounds are selected from the group comprising vanadium tetraethoxide, vanadium tetrapropoxide, vanadium tetrabutoxide, vanadium trichloride, vanadium tetrachloride, vanadium oxytrichloride, vanadium dichlorodiethoxide and/or the like. Vanadium tetrachloride and/or vanadium oxytrichloride are most preferred.

[0015] The transition metal compound which may be used for the synthesis of the solid catalyst precursor in the present invention is represented by the general formulas Tm(OR3)nX4−n, TmOX3 and Tm(R4)nX4−n, wherein Tm represents a transition metal of Group IVB, VB, or VIB, wherein R3 and R4 represent an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms, X represents a halogen atom and n represents a number satisfying 0≦n≦4. Non-limiting examples of the transition metal are titanium and vanadium, examples of R3 and R4 include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl and the like.

[0016] Preferred examples of the above mentioned transition metal compounds are selected from the group comprising titanium trichloromethoxide, titanium dichlorodimethoxide, titanium tetramethoxide, titanium trichloroethoxide, titanium dichlorodiethoxide, titanium tetraethoxide, titanium trichloropropoxide, titanium dichlorodipropoxide, titanium chlorotripropoxide, titanium tetrapropoxide, titanium trichlorobutoxide, titanium dichlorodibutoxide, titanium tetrabutoxide, vanadium tetrachloride, vanadium tetraethoxide, vanadium tetrapropoxide, vanadium tetrabutoxide, vanadium oxytrichloride, vanadium dichlorodiethoxide and/or the like. Titanium tetraethoxide, titanium tetrapropoxide and/or titanium tetrabutoxide are most preferred.

[0017] The alcohol compound which may be used for the synthesis of the solid catalyst precursor in the present invention includes compounds represented by the general formula R5OH, wherein R5 is an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms. Examples of R5 include groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, phenyl, methylphenyl, ethylphenyl and the like.

[0018] Preferred examples of the above mentioned alcohols are selected from the group comprising methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, cyclohexanol, phenol, methylphenol, ethylphenol and/or the like.

[0019] The magnesium compound used for the synthesis of the solid catalyst precursor in the present invention include Grignard compounds represented by the general formula R6MgX, wherein R6 is a hydrocarbon group having 1 to 20 carbon atoms and X is a halogen atom, preferably chlorine. Other preferred magnesium compounds are represented by the general formula R7R8Mg, wherein R7 and R8 are each a hydrocarbon group having 1 to 20 carbon atoms.

[0020] Preferred examples of the above mentioned magnesium compounds are selected from the group comprising dialkylmagnesium such as diethylmagnesium, di-n-propylmagnesium, di-isopropylmagnesium, di-nbutylmagnesium, di-isobutylmagnesium butylethylmagnesium, dihexylmagnesium, dioctylmagnesium, butyloctylmagnesium; alkylmagnesium chloride such as ethylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride and/or mixtures thereof.

[0021] The polymer particles used for the synthesis of the solid catalyst precursor in the present invention have a spherical shape with a mean particle diameter of about 5 to 1 000 microns and a pore volume of at least about 0.05 cm3/g and a pore diameter of about 20 to 10 000 angstroms, preferably from about 500 to 10 000 angstroms, and a surface area of about 0.1 m2/g to 100 m2/g, preferably from about 0.2 m2/g to 30 m2/g.

[0022] Examples of the above polymeric supports used in the catalyst preparation of the present invention are selected from the group comprising polymer particles of polyvinylchloride, polyvinylalcohol, polyketone, hydrolyzed polyketone, ethylene-vinylalcohol copolymer, polycarbonate and the like. Among these polymeric materials polyvinylchloride is more preferred and non-crosslinked polyvinylchloride particles are most preferred. Polyvinylchloride having a molecular weight in the range of about 5 000 to 500 000 g/mole is most preferred.

[0023] The use of the polymer particles mentioned in the present invention, in catalyst preparation offers significant advantages over traditional olefin polymerization catalysts using supports such as silica or magnesium chloride. In comparison to the silica supported catalyst, the polymer particles described in catalyst preparation of the present invention do not require high temperature and prolonged dehydration steps prior to their use in catalyst synthesis, thereby simplifying the synthesis process and thus reducing the overall cost of catalyst preparation. Further the cost of the polymeric support used in the present invention is substantially cheaper than silica or magnesium chloride supports. In addition, the cataiyst of the present invention uses significantly lower levels of catalyst components for catalyst preparation than silica or magnesium chloride supported catalysts. Also, the catalyst in the present invention is more active than conventional silica or magnesium chloride supported catalysts.

[0024] According to one embodiment of the present invention, a polyvinylchloride support is used. The synthesis of the solid catalyst precursor of the present invention involves introducing the polymeric material described above into a vessel and then adding: a diluent. Suitable diluents include isopentane, hexane, cyclohexane, heptane, isooctane and pentamethylheptane. The polymeric material is then treated with a magnesium compound described above at a temperature in the range of about 10° C. to 130° C. The ratio of magnesium compound to the polymer support may be in the range of about 0.05 mmol to 20 mmol per gram polymer, preferably 0.1 to 10 mmol per gram polymer. The solvent is then vaporized using a nitrogen purge at a temperature in the range of about 20° C. to 100° C.

[0025] The resulting free-flowing solid product is then slurried. Suitable solvents for slurring include isopentane, hexane, cyclohexane, heptane, isooctane and pentamethylheptane. The magnesium modified polymeric material is then treated with a transition metal compound and/or an alcohol described above at a temperature in the range of about 10° C. to 130° C. According to the present invention titanium tetramethoxide, titanium tetraethoxide, titanium tetraprbpoxide, titanium tetrabutoxide are preferred transition metal compounds and methanol, ethanol, n-propanol, isopropanol, n-butanol are preferred alcohols. The resulting material is then treated with a vanadium compound described above at a temperature in the range of about 10° C. to 130° C. According to the present invention vanadium tetrachloride and/or vanadium oxytrichloride are preferred vanadium compounds.

[0026] The produced solid catalyst precursor is then washed several times with a suitable solvent such as isopentane, hexane, cyclohexane, heptane, and isooctane. The solid catalyst precursor is then dried using a nitrogen purge at a temperature in the range of 20° C. to 100° C. In the final dried solid catalyst precursor, the molar ratio of vanadium to magnesium is in the range of about 0.01 to 50. In the case where the transition metal compound is used in catalyst preparation the molar ratio of vanadium to transition metal in the catalyst precursor is in the range of about 0.01 to 50, and in the case where alcohol is used in catalyst preparation the molar ratio of vanadium to OH groups in the catalyst precursor is in the range of about 0.01 to 50.

[0027] The catalyst compositions of the present invention are not subjected to halogenation treatments, for example chlorination treatments. The thus-formed catalyst precursor of the present invention is suitably activated by aluminum compounds, also known as cocatalysts, and unlike catalyst compositions described in the prior art the catalyst compositions of the present invention do not require promoters such as chloroform, trichlorofluoromethane or dibromomethane during polymerization.

[0028] The aluminum compounds, also known as cocatalyst, used in the present invention are represented by the general formula R9nAlX3−n, wherein R9 represents a hydrocarbon group having 1 to 10 carbon atoms; X represents a halogen and n represents. a number satisfying 0≦n≦3. Illustrative but not limiting examples include trialkylaluminums such as trimethylaluminum, triethylaluminum, tri-isobutylaluminum or tri-n-hexylaluminum; dialkylaluminum chloride such as dimethylaluminum chloride, diethylaluminum chloride. The preferred activators of the above general formula are trimethylaluminum, triethylaluminum, tri-isobutylaluminum and tri-n-hexylaluminum.

[0029] Examples of other suitable aluminum compounds of the present invention are represented by the general formula R10R11Al—O—AlR12R13, wherein R10, R11, R12 and R13 are either different linear, branched or cyclic alkyl group having 1 to 12 carbons, such as methyl, ethyl, propyl or isobutyl. The preferred examples are methylaluminoxane (MAO) and modified methylaluminoxane (MMAO). Further, mixtures of alkylaluminum compounds and aluminoxane compounds described above can also be conveniently used in the present invention.

[0030] The cocatalyst in the present invention can be used in an amount of about 10 to 5 000 in terms moles of aluminum in the cocatalyst to moles of transition metal in the catalyst precursor, and is preferably in the range of 20 to 3 000.

[0031] According to another object of the present invention there is provided a method for preparing a catalyst composition according to the present invention, comprising the steps of:

[0032] (i) combining the components of the solid catalyst precursor; and

[0033] (ii) activating the catalyst precursor with aluminum compound.

[0034] The catalyst precursor may be activated with the aluminum compound in part or in whole prior to or during polymerization.

EXAMPLES

[0035] The following examples are intended to be illustrative of this invention. They are, of course, not be taken in any way limiting on the scope of this invention. Numerous changes and modifications can be made with respect to the invention.

Example 1

Synthesis of Solid Catalyst Precursor (A)

[0036] To a three-necked round bottom flask, equipped with a condenser and stirrer, was placed 10.0 g of polyvinylchloride spheres with an average particle size of 36 microns. The flask containing the polyvinylchloride was heated up to 70° C. using an oil bath and then evacuated at 30 mm Hg pressure for 30 minutes. The flask and its contents were then purged with dried nitrogen and the polyvinylchloride was slurried using 30 cm3 of isopentane. Then 1.5 cm3 of butylmagnesium chloride (2.0 molar in diethylether) was added to the slurry and the resultant mixture was stirred for 60 minutes at an oil bath temperature of 35° C., under reflux conditions. The isopentane was then evaporated to obtain a free-flowing powder by using a nitrogen purge at 35° C.

[0037] Then the magnesium-modified polyvinylchloride was slurried using 30 cm3 of isopentane and 8.0 cm3 of vanadium tetrachloride (1.0 molar in n-hexane) was added to the slurryand the resulting mixture was stirred at 35° C. for 20 minutes. The supematant liquid was decanted and the resulting solid product was washed by stirring with 80 cm3 of isopentane and then removing the isopentane, then washed again twice with 80 cm3 of isoperiatne in each wash. Finally, the solid catalyst was dried using a nitrogen purge at 35° C. to yield a free-flowing brown colored solid product. The solid catalyst precursor was analyzed by atomic adsorption spectroscopy and was found to contain 0.59% by weight magnesium and 0.27% by weight vanadium.

Example 2

Ethylene Polymerization

[0038] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then 5.0 cm3 of tri-isobutylaluminum, TIBAL (1.0 molar in n-hexane) was injected into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “A” described in Example 1 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. 110 grams of polyethylene were recovered with a resin bulk density of 0.240 g/cm3 and a catalyst productivity of 1100 gPE/g catalyst.

Example 3

Synthesis of Solid Catalyst Precursor (B)

[0039] To a three-necked round bottom flask, equipped with a condenser and stirrer, was placed 10.0 g of polyvinylchloride spheres with an average particle size of 36 microns. The flask containing the polyvinylchloride was heated up to 70° C. using an oil bath and then evacuated at 30 mm Hg pressure for 30 minutes. The flask and its contents Were then purged with dried nitrogen and the polyvinylchloride was slurried using 30 cm3 of isopentane. Then 1.5 cm3 of butylmagnesium chloride (2.0 molar in diethylether) was added to the slurry and the resultant mixture was stirred for 60 minutes at an oil bath temperature of 35° C., under reflux conditions. The isopentane was then evaporated to obtain a free-flowing powder by using a nitrogen purge at 35° C.

[0040] Then the magnesium-modified polyvinylchloride was slurried using 30 cm3 of isopentane and 2.0 cm3 of ethanol (1.0 molar in n-hexane) was added to the slurry and the resulting mixture was stirred at 35° C. for 40 minutes. Then 8.0 cm3 of vanadium tetrachloride (1.0 molar in n-hexane) was added to contents of the flask and the resulting mixture was stirred at 35° C. for 20 minutes. The supernatant liquid was decanted and the resulting solid product was washed by stirring with 80 cm3 of isopentane and then removing the isopentane, then washed again twice with 80 cm3 of isopenatne in each wash. Finally, the solid catalyst was dried using a nitrogen purge at 35° C. to yield a free-flowing brown colored solid product. The solid catalyst precursor was analyzed by atomic adsorption spectroscopy and was found to contain 0.78% by weight magnesium and 1.03% by weight vanadium.

Example 4

Ethylene Polymerization

[0041] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then 5.0 cm of tri-isobutylaluminum, TIBAL (1.0 molar in n-hexane) was injected3 into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “B” described in Example 3 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. 150 grams of polyethylene were recovered with a resin bulk density of 0.243 g/cm3 and a catalyst productivity of 1500 gPE/g catalyst.

Example 5

Synthesis of Solid Catalyst Precursor (C)

[0042] To a three-necked round bottom flask, equipped with a condenser and stirrer, was placed 10.0 g of polyvinylchloride spheres with an average particle size of 36 microns. The flask containing the polyvinylchloride was heated up to 70° C. using an oil bath and then evacuated at 30 mm Hg pressure for 30 minutes. The flask and its contents were then purged with dried nitrogen and the polyvinylchloride was slurried using 30 cm3 of isopentane. Then 1.5 cm3 of butylmagnesium chloride (2.0 molar in diethylether) was added to the slurry and the resultant mixture was stirred for 60 minutes at an oil bath temperature of 35° C., under reflux conditions. The isopentane was then evaporated to obtain a free-flowing powder by using a nitrogen purge at 35° C.

[0043] Then the magnesium-modified polyvinylchloride was slurried using 30 cm3 of isopentane and 2.0 cm3 of titanium tetraethoxide (1.0 molar in n-hexane) was added to the slurry and the resulting mixture was stirred at 35° C. for 40 minutes. A dark green/brown colored solid was produced. Then 8.0 cm3 of vanadium tetrachloride (1.0 molar in n-hexane) was added to contents of the flask and the resulting mixture was stirred at 35° C. for 20 minutes. The supematant liquid was decanted and the resulting solid product was washed by stirring with 80 cm3 of isopentane and then removing the isopentane, then washed again twice with 80 cm3 of isopenatne in each wash. Finally, the solid catalyst was dried using a nitrogen purge at 35° C. to yield a free-flowing brown colored solid product. The solid catalyst precursor was analyzed by atomic adsorption spectroscopy and was found to contain 0.57% by weight magnesium, 0.54% by weight titanium and 1.77% by weight vanadium.

Example 6

Ethylene Polymerization

[0044] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then 5.0 cm3 of tri-isobutylaluminum, TIBAL (1.0 molar in n-hexane) was injected into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “C” described in Example 5 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. 390 grams of polyethylene were recovered with a resin bulk density of 0.290 g/cm3 and a catalyst productivity of 3900 gPE/g catalyst.

Examples 7-9

Ethylene Polymerization

[0045] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then the desired quantity of triethylaluminum, TEAL (1.0 molar in n-hexane), described in Table 1 below, was injected into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “C” described in Example 5 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. Results are described in Table 1.

TABLE 1
Influence of TEAL Concentration
	TEAL/	Yield/	Productivity/	Bulk Density/
Example	(mmol)	(g PE)	(g PE/g catalyst)	(g/cm3)
7	2	340	3400	0.272
8	4	500	5000	0.310
9	6	455	4550	0.303

Example 10, 11

Ethylene Polymerization

[0046] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. The reactor was then pressurized tthe desired hydrogen pressure, described in Table 2 below. Then 4.0 cm3 of triethylaluminum, TEAL (1.0 molar in n-hexane) was injected into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “C” described in Example 5 after being slurried in 20 cm3 of n-he xane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. Results are described in Table 2.

TABLE 2
Influence of Hydrogen Pressure
	Hydrogen
	Pressure/	Yield/	Productivity/	Bulk Density/
Example	(barg)	(g PE)	(g PE/g catalyst)	(g/cm3)
10	2	490	4900	0.290
8	3	500	5000	0.310
11	4	305	3050	0.260

Example 12

Ethylene-Butene Copolymerization

[0047] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. Then the desired quantity of butene, described in Table 3 below, was added to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then 4.0 cm3 of triethylaluminum, TEAL (1.0 molar in n-hexane). was injected into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “C” described in Example 5 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. Results are described in Table 3.

TABLE 3
Influence of Butene
	Butene/	Yield/	Productivity/	Bulk Density/
Example	(cm3)	(g PE)	(g PE/g catalyst)	(g/cm3)
8	0	500	5000	0.310
12	10	502	5020	0.300

Example 13

Ethylene-Hexene Copolymerization

[0048] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooline the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. Then the desired quantity of hexene, described in Table 4 below, was added to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then 4.0 cm3 of triethylaluminum, TEAL (1.0 molar in n-hexane) was injected into to the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “C” described in Example 5 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. Results are described in Table 4.

TABLE 4
Influence of Hexene
	Hexene/	Yield/	Productivity/	Bulk Density/
Example	(cm3)	(g PE)	(g PE/g catalyst)	(g/cm3)
8	0	500	5000	0.310
13	10	476	4760	0.302

Example 14

Svnthesis of Solid Catalyst Precursor (D)

[0049] To a three-necked round bottom flask, equipped with a condenser and stirrer, was placed 10.0 g of polyvinylchloride spheres with an average particle size of 36 microns. The flask containing the polyvinylchloride was heated up to 70° C. using an oil bath and then evacuated at 30 mm Hg pressure for 30 minutes. The flask and its contents were then purged with dried nitrogen and the polyvinylchloride was slurried using 30 cm3 of isopentane. Then 1.5 cm3 of butylmagnesium chloride (2.0 molar in diethylether) was added to the slurry and the resultant mixture was stirred for 60 minutes at an oil bath temperature of 35° C., under reflux conditions. The isopentane was then evaporated to obtain a free-flowing powder by using a nitrogen purge at 35° C.

[0050] Then the magnesium-modified polyvinylchloride was slurried using 30 cm3 of isopentane and 2.0 cm3 of titanium tetraethoxide (1.0 molar in n-hexane) was added to the slurry and the resulting mixture was stirred at 35° C. for 40 minutes. A dark green/brown colored solid was produced. Then 8.0 cm3 of vanadium oxytrichloride (1.0 molar in n-hexane) was added to contents of the flask and the resulting mixture was stirred at 35° C. for 20 minutes. The supernatant liquid was decanted and the resulting solid product was washed by stirring with 80 cm3 of isopentane and then removing the isopentane, then washed again twice with 80 cm3 of isopenatne in each wash. Finally, the solid catalyst was dried using a nitrogen purge at 35° C. to yield a free-flowing brown colored solid product. The solid catalyst precursor was analyzed by atomic adsorption spectroscopy and was found to contain 0.74% by weight magnesium, 0.56% by weight titanium and 1.50% by weight vanadium.

Example 15

Ethylene Polymerization

[0051] An autoclave with a volume of 3 liters was purged with nitrogen at 130° C. for 30 minutes. After cooling the autoclave to 85° C. the reactor was purged with hydrogen and then 1.5 liters of n-hexane were introduced to the reactor. The reactor was then pressurized to 3 barg hydrogen pressure. Then 4.0 cm3 of triethylaluminum, TEAL (1.0 molar in. n-hexane) was injected into the reactor. Ethylene was introduced to the reactor such as to raise the reactor pressure to 15 barg. This was followed by injection of 0.1 g of the solid catalyst precursor “D” described in Example 14 after being slurried in 20 cm3 of n-hexane solvent. Polymerization was carried out for 1 hour; with ethylene supplied on demand to maintain the total reactor pressure at 15 barg. 200 grams of polyethylene were recovered with a resin bulk density of 0.260 g/cm3 and a catalyst productivity of 2000 gPE/g catalyst.

[0052] The features disclosed in the foregoing description and/or in the claims may, both separately and in any combination thereof, be material for realising the invention in diverse forms thereof.

Claims

1. Catalyst composition for polymerization of olefins comprising: (a) a solid catalyst precursor comprising at least one vanadium compound, at least one magnesium compound and a polymeric material; and (b) a cocatalyst comprising at least one aluminum compound.

2. Catalyst composition according to claim 1 further comprising in component (a) at least one further transition metal compound and/or at least one alcohol.

3. Catalyst composition according to claim 1 or 2 wherein the vanadium compound is represented by the general formulas V(OR1)nX4−n, V(R2)nX4−n, VX3 and VOX3 wherein R1 and R2 represent an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl, X represents a halogen and n represents a number satisfying 0≦n≦4.

4. Catalyst composition according to claim 3 wherein the vanadium compound is selected from the group comprising vanadium tetraethoxide, vanadium tetrapropoxide, vanadium tetrabutoxide, vanadium trichloride, vanadium tetrachloride, vanadium oxytrichloride, vanadium dichlorodiethoxide and/or the like.

5. Catalyst composition according to claim 4 wherein the vanadium compound is vanadium tetrachloride and/or vanadium oxytrichloride.

6. Catalyst composition according to any of claims 2 to 5 wherein the transition metal compound is represented by the general formulas Tm(OR3)nX4−n, TmOX3 and Tm(R4)nX4−n wherein Tm is titanium or vanadium, R3 and R4 represent an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl, X represents a halogen atom and n represents a number satisfying 0≦n≦4.

7. Catalyst composition according to claim 6 wherein the transition metal compound is selected from the group comprising titanium trichloromethoxide, titanium dichlorodimethoxide, titanium tetramethoxide, titanium trichloroethoxide, titanium dichlorodiethoxide, titanium tetraethoxide, titanium trichloropropoxide, titanium dichlorodipropoxide, titanium chlorotripropoxide, titanium tetrapropoxide, titanium trichlorobutoxide, titanium dichlorodibutoxide, titanium tetrabutoxide, vanadium tetrachloride, vanadium tetraethoxide, vanadium tetrapropoxide, vanadium tetrabutoxide, vanadium oxytrichloride, vanadium dichlorodiethoxide and/or the like.

8. Catalyst composition according to claim 7 wherein the transition metal compound is titanium tetraethoxide, titanium tetrapropoxide and/or titanium tetrabutoxide.

9. Catalyst composition according to any of claims 2 to 8 wherein the alcohol is represented by the general formula R5OH, wherein R5 is an alkyl group, aryl group or cycloalkyl group having 1 to 20 carbon atoms.

10. Catalyst composition according to claim 9 wherein the alcohol is selected from the group comprising methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, cyclohexanol, phenol, methylphenol, ethylphenol and/or mixtures thereof.

11. Catalyst composition according to any of the preceding claims wherein the magnesium compound is a Grignard compound represented by the general formula R6MgX wherein R6 is a hydrocarbon group having 1 to 20 carbon atoms and X is a halogen atom, and/or a dialkyl magnesium compound represented by the general formula R7R8Mg wherein R7 and R8 are each a hydrocarbon group having 1 to 20 carbon atoms.

12. Catalyst composition according to claim 11 wherein the magnesium compound is diethylmagnesium, di-n-propylmagnesium, di-isopropylmagnesium, di-n-butylmagnesium, di-isobutylmagnesium butylethylmagnesium, dihexylmagnesium, dioctylmagnesium, butyloctylmagnesium, ethylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride and/or mixtures thereof.

13. Catalyst composition according to any of the preceding claims wherein the polymeric material is in the form of particles having a mean particle diameter of about 5 to 1 000 microns and a pore volume of at least about 0.05 cm3/g and a pore diameter of about 20 to 10 000 angstroms and a surface area of about 0.1 m2/g to 100 m2/g.

14. Catalyst composition according to claim 13 wherein the pore diameter is from about 500 to 10 000 angstroms and the surface area is from about 0.2 m2/g to 30 m2/g.

15. Catalyst composition according to any of the preceding claims wherein the polymeric material is selected from the group comprising polyvinylchloride, polyvinylalcohol, polyketone, hydrolyzed polyketone, ethylene-vinylalcohol copolymer, polycarbonate and the like.

16. Catalyst composition according to claim 15 wherein the polymeric material is polyvinylchloride.

17. Catalyst composition according to claim 16 wherein the polyvinylchloride has a molecular weight in the range of about 5 000 to 500 000 g/mole.

18. Catalyst composition according to any of the preceding claims wherein the magnesium compound is used in the range of about 0.05 mmol to 20 mmol per gram of polymeric material.

19. Catalyst composition according to any of the preceding claims wherein the molar ratio of vanadium to magnesium in the catalyst precursor is in the range of about 0.01 to 50.

20. Catalyst composition according to any of claims 2 to 19 wherein the molar ratio of vanadium to transition metal compound in the catalyst precursor is in the range of about 0.01 to 50.

21. Catalyst composition according to any of the preceding claims 2 to 20 wherein the molar ratio of vanadium to OH groups in the catalyst precursor when alcohol is used is in the range of about 0.01 to 50.

22. Catalyst composition according to any of the preceding claims wherein the aluminum compound is represented by the general formula R9nAlX3−n wherein R9 represents a hydrocarbon group having 1 to 10 carbon atoms, X represents a halogen and n represents a number satisfying 0≦n≦3.

23. Catalyst composition according to claim 22 wherein the aluminum compound is trimethylaluminum, triethylaluminum, tri-isobutylaluminum or tri-n-hexylaluminum.

24. Catalyst composition according to any of the preceding claims 1 to 21 wherein the aluminum compound is represented by the general formula R10R11Al—O—AlR12R13 wherein R10, R11, R12 and R13 are either the same or different linear, branched or cyclic alkyl group having 1 to 12 carbons, such as methyl, ethyl, propyl or isobutyl.

25. Catalyst composition according to claim 24 wherein the aluminum compound is methyl aluminoxane (MAO) or modified methyl aluminoxane (MMAO).

26. Catalyst composition according to any of the preceding claims wherein the aluminum compound is a mixture of an alkylaluminum and an aluminoxane.

27. Catalyst composition according to any of the preceding claims wherein the cocatalyst is used in an amount of about 10 to 5 000 in terms moles of aluminum in the cocatalyst to moles of transition metal in the catalyst precursor.

28. Method for preparing a catalyst composition according to any of the claims 1 to 27 comprising the steps of: (a) combining the components of the solid catalyst precursor; and (b) activating the catalyst precursor with aluminum compound.

29. Method according to claim 28 wherein the catalyst precursor is activated with the aluminum compound in part or in whole prior to or during polymerization.