CATALYST SYSTEM FOR THE POLYMERISATION AND/OR OLIGOMERISATION OF OLEFINS AND PROCESS UTILIZING THE CATALYST SYSTEM

Abstract

The present invention relates to a synergistic dual olefin copolymerization catalyst system comprising a solid support material having, on its surface, two or more catalytic metal complexes wherein the two or more catalytic metal complexes comprise at least one first transition metal complex and a second transition metal complex different from the first transition metal complex; use of such a system as a catalyst; a process for producing a polymer of an olefin utilizing the catalyst system.

Claims

1. A synergistic dual olefin copolymerisation catalyst system comprising a solid support material having, on its surface, two or more catalytic metal complexes wherein the two or more catalytic metal complexes comprise at least one first transition metal complex and a second transition metal complex different from the first transition metal complex.

2. The synergistic dual olefin copolymerisation catalyst system according to claim 1 wherein the first transition metal complex is an olefin polymerisation catalyst and the second transition metal complex is an olefin oligomerisation catalyst.

3. The system according to claim 1, wherein the second transition metal complex is a chromium containing complex.

4. The system according to claim 1, wherein the second transition metal complex is a chromium-permethylpentalene derived complex or a chromium cyclopentadienyl complex.

5. The system according to claim 1, wherein the first transition metal complex is at least one complex of a metal selected from zirconium, iron, chromium, cobalt, nickel, titanium and hafnium containing one or more aromatic or heteroaromatic ligands.

6. The system according to claim 3, wherein first transition metal complex is at least one complex selected from ##STR00005##

7. The system according to claim 1, wherein the second transition metal complex is a complex of chromium and a ligand derived from permethylpentalene having the formula [Pn*(H)CrCl.sub.2].sub.2, where Pn* is a permethylpentalene moiety.

8. The system according to claim 1, wherein the solid support material is selected from a layered double hydroxide activated with an alkylaluminoxane, silica activated with an alkylaluminoxane, and solid alkylaluminoxane.

9. The system according to claim 8, wherein the alkylaluminoxane is methylaluminoxane.

10. The system according to claim 1, wherein the weight or molar ratio of the first transition metal complex to the second transition metal complex is from 95:5 to 50:50.

11. (canceled)

12. A process for producing a polymer of an olefin which comprises contacting the olefin with a synergistic dual solid catalyst system comprising a solid support material having, on its surface, two or more catalytic metal complexes wherein the two or more catalytic metal complexes comprise at least one first transition metal complex and a second transition metal complex different from the first transition metal complex.

13. The process according to claim 12, wherein the olefin is ethylene.

14. The process according to claim 12, wherein the polymer is a copolymer.

15. The process according to claim 13, wherein the polymer is a copolymer.

16. The system according to claim 1, wherein the weight or molar ratio of the first transition metal complex to the second transition metal complex is from 90:10 to 70:30.

17. The system according to claim 1, wherein the weight or molar ratio of the first transition metal complex to the second transition metal complex is from 90:10 to 75:25.

Description

[0032] Further advantages and features of the subject matter of the present invention can be taken from the following detailed examples section illustrating preferred embodiments in conjunction with the attached drawing, wherein

[0033] FIG. 1 illustrates productivity results achieved for different catalyst systems according to the present invention; polymerisation of ethylene using LDH/MAO/[complexes] catalysts with a weight ratio zirconium:chromium complex of 75:25 under the condition: 10mg of catalyst, 2 bar, 1 hour, 60 or 80 C., 150mg of TIBA, Hexane (50 mL), LDH:MgAlCO.sub.3.

[0034] FIG. 2 shows differential scanning calorimetric spectra of polyethylene obtained in the comparative example and according to the present invention; differential scanning calorimetric spectra of polyethylene using bottom, LDH/MAO/[.sup.2-Me,4-PhSBI)ZrCl.sub.2] catalyst and top) LDH/MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 75:25 catalyst under the condition: MgAlCO.sub.3, 10 mg of catalyst, 1 bar, 0.5 hour, 150 mg of TIBA, Hexane (50 mL).

[0035] FIG. 3 illustrates SEM images of polyethylene using a) LDH/MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2] catalyst and b) LDH/MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 75:25 catalyst under the condition: MgAlCO.sub.3, 10 mg of catalyst, 1 bar, 0.5 hour, 150 mg of TIBA, Hexane (50 mL).

[0036] FIG. 4 illustrates the dependency of weight ratio of first and second transition metal catalyst on activity and productivity; polymerisation of ethylene using LDH/MAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalysts with a various weight ratio under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 mL), LDH:MgAlCO.sub.3.

[0037] FIG. 5 illustrates the dependency of weight ratio of first and second transition metal catalyst on activity and productivity; polymerisation of ethylene using LDH/MAO/[(.sup.nBuCp).sub.2ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalysts with a various weight ratio under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 mL), LDH:MgAlCO.sub.3.

[0038] FIG. 6 illustrates .sup.13CNMR spectra for a polyethylene obtained with a catalyst of the present invention; .sup.13C{.sup.1H} NMR spectra in CD.sub.4Cl.sub.2 at 383 K of polyethylene synthesised using LDH/MAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalysts with a various weight ratio under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 mL), LDH:MgAlCO.sub.3.

[0039] FIG. 7 illustrates a .sup.1H NMR spectra for a polyethylene obtained by catalyst system according to the present invention; .sup.1H NMR spectra in CD.sub.4Cl.sub.2 at 383 K of polyethylene synthesised using LDH/MAO/[(EBI)ZrCl.sub.2]:[Pn*(H)Cr Cl.sub.2].sub.2 catalysts with a various weight ratio under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 mL), LDH: MgAlCO.sub.3.

[0040] FIG. 8 illustrates the dependency of molar ratio of first and second transition metal catalyst on activity; polymerisation of ethylene using LDH/MAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalysts with various molar ratios under the condition: 10 mg of catalyst, 2 bar, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL), LDH: MgAlCO.sub.3.

[0041] FIG. 9 illustrates the dependency of molar ratio of first and second transition metal catalyst on activity; polymerisation of ethylene using SMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalysts with various molar ratio under the condition: 10 mg of catalyst, 2 bar, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL), SMAO.

[0042] FIG. 10 illustrates a comparison of molar ratio of [Transition metal 1]/[Transition metal 2] in the tandem system (LDHMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)Cr Cl.sub.2].sub.2 and mixing separate systems (LDHMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 and LDHMAO/[Pn*(H)CrCl.sub.2].sub.2) using LDHMAO under the condition: 10 mg of catalyst, 2 bar, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL), LDH: MgAlCO.sub.3.

[0043] FIG. 11 illustrates a comparison of molar ratio of [Transition metal 1]/[Transition metal 2] in the tandem system (LDHMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)Cr Cl.sub.2].sub.2) and mixing separate systems (LDHMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 and LDHMAO/[Pn*(H)CrCl.sub.2].sub.2 using SMAO under the condition: 10 mg of catalyst, 2 bar, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL), SMAO.

[0044] FIG. 12 illustrates an effect on polymerisation activity when [Zr]:[Cr] ratio is modified. SMAO[Zr][Cr] catalysts with various molar ratios under the conditions: 10 mg of catalyst, 2 bar, 1 h, 60 C., 150 mg TIBA, Hexane (50 mL). [Al].sub.MAO/([Cr]+[M]).sub.0=300.

[0045] FIG. 13 illustrates an effect on polymerisation activity when [Zr]:[Cr] ratio is modified. SMAO[Zr][Cr] catalysts with various molar ratios under the conditions: 10 mg of catalyst, 2 bar, 1 h, 60 C., 150 mg TIBA, Hexane (50 mL). [Al].sub.MAO/([Cr]+[M]).sub.0=300.

[0046] FIG. 14 illustrates an effect on polymerisation activity when LDHMAO[Zr] systems are prepared containing the same molar amount of [Zr] to the tandem catalysts analogue. Conditions: 10 mg of catalyst, 2 bar, 1 h, 60 C., 150 mg TIBA, Hexane (50 mL). [Al].sub.MAO/([Cr]+[M]).sub.0=100, LDH=AMOMgAlCO.sub.3.

[0047] FIG. 15 illustrates molecular weights and distributions recorded by GPC when [Zr]:[Cr] ratio is modified. LDHMAO or SMAO[Zr][Cr] catalysts with various molar ratios under the conditions: 10 mg of catalyst, 2 bar, 1 h, 60 C., 150 mg TIBA, Hexane (50 mL). [Al].sub.MAO/([Cr]+[M]).sub.0=300 for sMAO and 100 for LDHMAO. LDH=AMOMgAlCO.sub.3.

[0048] FIG. 16 illustrates a comparison of sMAO[Zr][Cr] ([Zr]:[Cr]=75:25). 25 mg catalyst, pressure variable (8 barblue line, 6 barpurple line, 4 barred line), 1 h, 80 C., [Al].sub.MAO/([Cr]+[M]).sub.0=300, TEA scavenger.

[0049] FIG. 17 illustrates a gel permeation chromatography data obtained from polymerisation of ethylene using sMAO[Zr][Cr] catalyst under the conditions: 1 hour, 80 C., 2.5 mL TEA, Hexane (1 L), [Al].sub.MAO/([Cr]+[M]).sub.0=300.

[0050] FIG. 18 illustrates a TREF data obtained from polymerisation of ethylene using sMAO[Zr].sub.60[Cr].sub.40 catalyst under the conditions: 1 hour, 80 C., 2.5 mL TEA, Hexane (1 L), [Al].sub.MAO/([Cr]+[M]).sub.0=300.

[0051] FIG. 19 illustrates a TREF data obtained from polymerisation of ethylene using sMAO[Zr].sub.60[Cr].sub.40 catalyst under the conditions: 1 hour, 8 bar, 2.5 mL TEA, Hexane (1 L), [Al].sub.MAO/([Cr]+[M]).sub.0=300.

[0052] FIG. 20 illustrates a .sup.13C{.sup.1H} NMR spectroscopic data from the polymer produced using sMAO[Zr].sub.60[Cr].sub.40 catalyst under the conditions: 1 hour, 8 bar, 80 C., 2.5 mL TEA.

[0053] FIG. 21 illustrates a .sup.13C{.sup.1H} NMR spectroscopic data from the polymer produced using sMAO[Zr].sub.60[Cr].sub.40 catalyst under the conditions: 1 hour, 4 bar, 80 C., 2.5 mL TEA.

[0054] FIG. 22 illustrates a differential scanning calorimetry data from the polymer produced using sMAO catalyst under the general conditions: 1 hour, 2.5 mL TEA.

EXAMPLES

Example 1

[0055] 1.1 Synthesis of Solid Support Material

[0056] Thermally-treated support material (SiO.sub.2 (SS) or an acetone-dispersed Layered Double Hydroxide (LDH)) was weighed and slurried in toluene. Methylaluminoxane (MAO), with a solid support:MAO mole ratio of 2:1, was prepared in toluene solution and added to the thermally-treated solid support slurry. The resulting slurry was heated at 80 C. for 2 h with occasional swirling. The product was then filtered, washed with toluene, and dried under dynamic vacuum to afford the final solid support material (LDHMAO, and SSMAO) in quantitative yield.

[0057] Solid MAO (SMAO) was received from SCG Chemicals, dried to afford colourless free-flowing powder and used as is.

[0058] The solid support materials used in the examples provided below were MAO treated silica (SSMAO);

[0059] MAO treated acetone-dispersed LDH (LDHMAO); and solid MAO (SMAO).

[0060] 1.2 Synthesis of a Synergistic Dual-catalyst

[0061] Solid support material prepared as described above was weighed and slurried in toluene. The solution of at least two complexes (described below) in toluene with support:complexes weight ratio of 0.02 was prepared and added to the support slurry. The resulting slurry was heated at 80 C. for 2 h with occasional swirling or until the solution became colourless. The product was then filtered, washed with toluene and dried under dynamic vacuum to afford the synergistic dual catalyst.

[0062] It is also possible to mix the support and at least two complexes in the same Schlenk and then add the toluene. The reaction conditions and work-up are identical as described above.

[0063] It is also possible to mix at least both complexes with MAO in a toluene solution and to add them into a slurry of the solid support in toluene. The reaction conditions and work-up are identical as described above.

[0064] The first transition metal complex used in the preparation of the dual catalyst system in the Examples was selected from

##STR00004##

[0065] The second transition metal complex used in the preparation of the dual catalyst system was the compound having the formula [Pn*(H)CrCl.sub.2].sub.2. This was prepared according to the following synthetic procedure.

[0066] (A) Synthesis of (Pn*(H)CrCl.sub.2].sub.2

[0067] To a slurry of CrCl.sub.3 (0.0981g, 0.619 mmole) in benzene was added a solution of Pn*(H)SnMe.sub.3 (0.218 g, 0.619 mmole) in benzene. The reaction mixture was heated to 80 C. for 5 days to afford a dark-green solution. The reaction mixture was filtered and the volatiles were removed in vacuo to afford a dark-green powder which was washed with pentane and dried under reduced pressure to yield [Pn*(H)CrCl.sub.2].sub.2 as a dark-green powder. The complex is paramagnetic. The yield was 67%.

[0068] (B) Characterisation of [Pn*(H)CrCl.sub.2].sub.2

[0069] 1H NMR spectrum (C.sub.6D.sub.6:23 C.) range is 36.0 to 18.3 ppm.

[0070] The polymerisation of ethylene was studied using the dual catalyst systems. To demonstrate the different productivities between the various complexes, a weight ratio of first transition metal catalyst:chromium-hydro(permethylpentalene) complex of 75:25 was chosen.

[0071] A. Polymerisation of Ethylene [0072] catalyst: MgAlCO.sub.3 LDH MAO/[complex 1]:[Pn*(H)CrCl.sub.2].sub.2 [0073] solvent: hexane 50 ml [0074] amount of catalyst: 10 mg [0075] ethylene feed: 200 kPa (2 bar) [0076] reaction time: 1 hour [0077] reaction temperatures: 60 C. and 80 C. [0078] Trilsobutylaluminium (TIBA): 150 mg

[0079] The results of the polymerisations are shown in Table 1 and FIG. 1.

TABLE-US-00001 TABLE 1 Temperature Productivity Complex 1 Complex 2 ( C.) kg.sub.PE/g.sub.CAT|h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 60 0.129 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80 0.205 [(EBI*)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80 0.085 [(.sup.MesPDI)FeCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 60 0.545 [(.sup.MesPDI)FeCl.sub.2]LDH [Pn*(H)CrCl.sub.2].sub.2 80 0.404 [(.sup.nBuCp).sub.2ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 60 0.283 [(.sup.nBuCp).sub.2ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80 0.156

[0080] The results shown in Table 1 and FIG. 1 demonstrate that the MgAlCO.sub.3 LDH/[(.sup.MesPDI)FeCl.sub.2] catalyst achieved the highest productivities at 60 C. and 80 C. (0.545 and 0.404 kg.sub.PE/g.sub.CAT/h, respectively). The results for the other complexes varied with the temperature. Productivities increased with increases in temperature, with the exception of the [(EBI)ZrCl.sub.2] based catalyst.

[0081] B. Polymerisation of Ethylene [0082] catalyst: MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-Ph-SBI)ZrCl.sub.2].[Pn*(H)CrCl.sub.2].sub.2 [0083] solvent: hexane (50 ml) [0084] amount of catalyst: 10 mg [0085] ethylene feed: 200 kPa (2 bar) [0086] reaction time: 0.5 hour [0087] reaction temperature: 80 C. [0088] TIBA: 150 mg

[0089] The results of the polymerisations are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Temperature Aluminium Productivity Complex 1 Complex 2 ( C.) scavenger kg.sub.PE/g.sub.CAT|h [(.sup.2-Me,4-Ph-SBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80 TIBA 0.130 [(.sup.2-Me,4-Ph-SBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80 MAO 0.126

[0090] Ethylene polymerisations using MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 with TIBA or MAO as scavenger demonstrated the same productivities (0.130 and 0.126 kg.sub.PE/g.sub.CAT/h respectively).

[0091] FIG. 2 shows the differential scanning calorimetric spectra of polyethylene using, as catalyst, [0092] (1) TopMgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 75:25 [0093] (2) BottomMgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]

[0094] Conditions employed for (1) and (2): [0095] solvent: hexane (50 ml) [0096] amount of catalyst: 10 mg [0097] ethylene feed: 100 kPa (1 bar) [0098] reaction time: 0.5 hour [0099] TIBA: 150 mg

[0100] FIG. 2 demonstrates that there is a broadening of the differential scanning calorimetric spectra when the dual catalyst system was used in comparison with the single catalyst system.

[0101] This broadening is characteristic of ethylene/-olefin co-polymerisations. The polymerisation was, however, carried out using only a single ethylene feed. The scanning electron microscope image in FIG. 3 demonstrates the flower type particles of the polyethylene, this is similar to the LDH starting material.

[0102] C. When the polymerisations were carried out in a 2 L reactor (1000 mL of hexane, 1 h, 80 C. and 8 bar) the productivity using MgAlCO.sub.3 LDM MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 75:25 was 0.55 kg.sub.PE/g.sub.CAT/h, 4 times higher than when 50 mL of solvent is used. The polyethylene possessed very large particle size (70% of 500 m, 17% of 250 m and other smaller ones), comparing to those obtained when MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2] was used as a catalyst (58% of 500 m, 23% of 250 m and other smaller ones).

[0103] The molecular weights were similar, 531505 g/mol for MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 and 567861 g/mol for MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]. However, there is an increase of 3 fold in the bulk CH.sub.3 per 1000 C from 0.665 for MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2] to 1.429 for MgAlCO.sub.3 LDH MAO/[(.sup.2-Me,4-PhSBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2.

[0104] The molecular weights are weight average molecular weight (M.sub.W) and were determined by Gel Permeation Chromatography (GPC).

[0105] D. Variation of the Weight Ratio Using LDHMAO

[0106] To try to understand the effect the weight ratio of zirconium:chromium in the dual catalyst system has on the activities, several different weight ratios were chosen and the results are collated in Tables 3 and 4, and FIGS. 4 and 5.

TABLE-US-00003 TABLE 3 Polymerisation of ethylene using MgAlCO.sub.3 LDH MAO/ [(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 ml). Weight Productivity Activity Complex 1 Complex 2 Ratio kg.sub.PE/g.sub.CAT/h kg.sub.PE/.sub.molZr complex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 100:00 0.147 3076 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 90:10 0.171 3976 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80:20 0.191 4996 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 0.205 5720 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 70:30 0.138 4124 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 50:50 0.081 3389 [(EBI)ZrCl.sub.2] none 0:100 0.003 negligible

[0107] Table 3 and FIG. 4 show that when using MgAlCO.sub.3 LDH MAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2, the weight ratio of 75:25 provided the highest activity (5720 kg.sub.PE/mol.sub.Zr complex/h). Adding the [Pn*(H)CrCl.sub.2].sub.2 complex demonstrated a direct effect on the activities with 25% in weight increased them by 2 fold factor in comparison of the catalyst based on pure [(EBI)ZrCl.sub.2]. The morphology of the polymers changed with the ratio of LDH MAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 as shown in FIGS. 6 and 7. The Figures show that there is a broadening of the NMR spectra with an increase in chromium. This demonstrates the presence of branching in the polymer.

TABLE-US-00004 TABLE 4 Polymerisation of ethylene using MgAlCO.sub.3 LDH MAO/ [(.sup.nBuCp).sub.2ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 ml). Weight Productivity Activity Complex 1 Complex 2 Ratio kg.sub.PE/g.sub.CAT/h kg.sub.PE/.sub.molZr complex/h [(.sup.nBuCp).sub.2ZrCl.sub.2] none 100:00 0.063 1079 [(.sup.nBuCp).sub.2ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 80:20 0.171 4345 [(.sup.nBuCp).sub.2ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 0.155 4194 [(.sup.nBuCp).sub.2ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 70:30 0.148 4262 none [Pn*(H)CrCl.sub.2].sub.2 0:100 0.003 negligible

[0108] Table 4 and FIG. 5 show that when using LDH MAO/[(.sup.nBuCp).sub.2ZrCl.sub.2]:[Pn*(H) CrCl.sub.2].sub.2, the weight ratio of 80:20 provided the highest activity and productivity (4345 kg.sub.PE/mol.sub.Zrcomplex/h and 0.171 kg.sub.PE/g.sub.CAT/h respectively). Adding the [Pn*(H)CrCl.sub.2].sub.2 complex demonstrated a direct effect on the activities with an increase by 4 fold factor in comparison of the catalyst based on pure [(.sup.nBuCp).sub.2ZrCl.sub.2]. The activities remain constant with addition of more [Pn*(H)CrCl.sub.2].sub.2; however, the productivities decrease.

[0109] Similar polymerisations have been carried out using a zirconium complex based on permethylpentalene ligand [Pn*(H)ZrCl.sub.3].sub.2.

TABLE-US-00005 TABLE 5 Polymerisation of ethylene using MgAlCO.sub.3 LDH/MAO/ [Pn*(H)ZrCl.sub.3].sub.2:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 ml). Weight Productivity Activity Complex 1 Complex 2 Ratio kg.sub.PE/g.sub.CAT/h kg.sub.PE/.sub.molZr complex/h [Pn*(H)ZrCl.sub.3].sub.2 none 100:0 0.0055 192 [Pn*(H)ZrCl.sub.3].sub.2 [Pn*(H)CrCl.sub.2].sub.2 75:25 0.0072 335

[0110] Activity increases by 75% when the chromium complex was incorporated (335 kg.sub.PE/mol.sub.Zr complex/h instead of 192 kg.sub.PE/mol.sub.Zr complex/h).

[0111] E. Variation of the Solid Support

[0112] To understand the effect of the support on the productivity, three supports have been tested (MgAlCO.sub.3 LDHMAO, SSMAO and SMAO). The results are collated in Table 6.

TABLE-US-00006 TABLE 6 Polymerisation of ethylene using support/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 ml). Weight Productivity Activity Complex 1 Complex 2 Ratio Support kg.sub.PE/g.sub.CAT/h kg.sub.PE/mol.sub.Zrcomplex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 LDHMAO 0.205 5720 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 SSMAO 0.167 4660 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 SMAO 0.785 21900 LDHMAO = acetone-dispersed MgAlCO.sub.3 LDH treated with MAO; SSMAO = calcined SiO.sub.2 treated with MAO; SMAO = solid methyialuminoxane

[0113] Solid MAO (SMAO) (21900 kg.sub.PE/mol.sub.Zr complex/h) is four to five times faster than LDHMAO (5720 kg.sub.PE/mol.sub.Zr complex/h) and SSMAO (4660 kg.sub.PE/mol.sub.Zrcomplex/h) respectively.

[0114] F. Variation of [Al].sub.0/[M].sub.0 on Solid MAO

[0115] To understand the effect of the amount of complex on the support on the productivity, two amounts have been tested. The results are collated in Table 7.

TABLE-US-00007 TABLE 7 Polymerisation of ethylene using MgAlCO.sub.3 LDH MAO/ [(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar, 1 hour, 80 C., 150 mg of TIBA, Hexane (50 ml). Weight Productivity Activity Complex 1 Complex 2 Ratio [Al].sub.0/[M].sub.0 kg.sub.PE/g.sub.CAT/h kg.sub.PE/mol.sub.Zrcomplex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 300 0.785 21902 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 100 0.699 6078

[0116] Solid MAO with a ratio [Al].sub.0/[M].sub.0 of 300 (21900 kg.sub.PE/mol.sub.Zr complex/h) is 3.5 times faster than with a ratio [Al].sub.0/[M].sub.0 of 100 (6078 kg.sub.P/mol.sub.Zr complex/h).

[0117] G. Variation of Molar Ratio of [Transition Metal 1]/[Transition Metal 2] Using LDHMAO

[0118] To try to understand the effect the molar ratio of transition metal 1/transition metal 2 has on activity, the relative ratio was varied, whilst maintaining a total [Al].sub.0/[M].sub.0 of 100. The results are collated in Table 8 and FIG. 8.

TABLE-US-00008 TABLE 8 Polymerisation of ethylene using support/ [(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar ethylene, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL). Molar Ratio (Complex Activity Complex 1 Complex 2 1:Complex 2) kg.sub.PE/mol.sub.Zrcomplex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 100:0 2381 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 3860 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 50:50 3718 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 40:60 2669 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 0:100 negligible LDHMAO = acetone-dispersed MgAlCO.sub.3 LDH treated with MAO

[0119] Table 8 and FIG. 8 show that when using LDHMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2, the molar ratio of 75:25 provided the highest activity (3860 kg.sub.PE/mol.sub.Zrcomplex/h). All system compositions that include [Pn*(H)CrCl.sub.2].sub.2 demonstrate a higher activity than the 100:0 molar ratio. Negligible activity was observed when the molar ratio was 0:100 (i.e. no [(EBI)ZrCl.sub.2] was present).

[0120] H. Variation of Molar Ratio of [Transition Metal 1]/[Transition Metal 2] Using SMAO

[0121] To try to understand the effect the molar ratio of transition metal 1/transition metal 2 has on activity, the relative ratio was varied, whilst maintaining a total [Al].sub.0/[M].sub.0 of 300. The results are collated in Table 9 and FIG. 9.

TABLE-US-00009 TABLE 9 Polymerisation of ethylene using support/ [(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst under the condition: 10 mg of catalyst, 2 bar ethylene, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL). Molar Ratio (Complex Activity Complex 1 Complex 2 1:Complex 2) kg.sub.PE/mol.sub.Zrcomplex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 100:0 15459 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 17482 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 60:40 23784 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 50:50 20687 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 40:60 19466 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 0:100 negligible SMAO = solid methylaluminoxane

[0122] Table 9 and FIG. 9 show that when using SMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2, the molar ratio of 60:40 provided the highest activity (23784 kg.sub.PE/mol.sub.Zrcomplex/h). All system compositions that include [PN*(H)CrCl.sub.2].sub.2 demonstrate a higher activity than the 100:0 molar ratio. Negligible activity was observed when the molar ratio was 0:100 (i.e. no [(EBI)ZrCl.sub.2] was present).

[0123] I. Comparison of Molar Ratio of [Transition Metal 1]/[Transition Metal 2] in the Tandem System and Mixing Separate Systems Using LDHMAO.

[0124] To try to understand the synergistic effect on activity observed at different molar ratios of transition metal 1/transition metal 2, the relative ratio was varied, whilst maintaining a total [Al].sub.0/[M].sub.0 of 100; these values for activity were then compared to polymerisation runs where the [Al].sub.0/[M].sub.0 of 100 and molar ratios of transition metal 1/transition metal 2 were maintained but the transition metal complexes 1 and 2 were separately supported on LDHMAO and mixed together prior to polymerisation. The results are collated in Table 10 and FIG. 10.

TABLE-US-00010 TABLE 10 Polymerisation of ethylene using support/[(EBI)ZrCl.sub.2]:[Pn*)H)CrCl.sub.2].sub.2 catalyst and mixed support/[(EBI)ZrCl.sub.2] and support/[Pn*(H)CrCl.sub.2].sub.2 catalysts under the condition: 10 mg of catalyst, 2 bar ethylene, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL). Tandem Mixed Molar Ratio Catalyst Catalyst (Complex Activity Activity Complex 1 Complex 2 1:Complex 2) kg.sub.PE/mol.sub.Zrcomplex/h kg.sub.PE/mol.sub.Zrcomplex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 100:0 2381 2381 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 3860 2694 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 50:50 3718 3065 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 40:60 2669 3123 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 0:100 negligible Negligible LDHMAO = acetone-dispersed MgAlCO.sub.3 LDH treated with MAO

[0125] Table 10 and FIG. 10 show that for transition metal 1/transition metal 2 ratios of 75:25 and 50:50, the activity is significantly higher when using LDHMAO/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 than the corresponding mixed catalysts in the same molar ratio. This demonstrates a clear synergistic effect at these ratios. For a transition metal 1/transition metal 2 ratio of 40:60, the values for activity are the same within error. All system compositions that include [Pn*(H)CrCl.sub.2].sub.2 demonstrate a higher activity than the 100:0 molar ratio. Negligible activity was observed when the molar ratio was 0:100 (i.e. no [(EBI)ZrCl.sub.2] was present).

[0126] J. Comparison of Molar Ratio of [Transition metal 1]/[Transition metal 2] in the Tandem System and Mixing Separate Systems Using SMAO.

[0127] To try to understand the synergistic effect on activity observed at different molar ratios of transition metal 1/transition metal 2, the relative ratio was varied, whilst maintaining a total [Al].sub.0/[M].sub.0 of 300; these values for activity were then compared to polymerisation runs where the [Al].sub.0/[M].sub.0 of 300 and molar ratios of transition metal 1/transition metal 2 were maintained but the transition metal complexes 1 and 2 were separately supported on SMAO and mixed together prior to polymerisation. The results are collated in Table 11 and FIG. 10.

TABLE-US-00011 TABLE 11 Polymerisation of ethylene using support/[(EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2 catalyst and mixed support/[(EBI)ZrCl.sub.2] and support/[Pn*(H)CrCl.sub.2].sub.2 catalysts under the condition: 10 mg of catalyst, 2 bar ethylene, 1 hour, 60 C., 150 mg of TIBA, Hexane (50 mL). Tandem Mixed Molar Ratio Catalyst Catalyst (Complex Activity Activity Complex 1 Complex 2 1:Complex 2) kg.sub.PE/mol.sub.Zrcomplex/h kg.sub.PE/mol.sub.Zrcomplex/h [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 100:0 15459 15459 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 75:25 17482 18102 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 60:40 23784 18119 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 50:50 20688 19558 [(EBI)ZrCl.sub.2] [Pn*(H)CrCl.sub.2].sub.2 40:60 19466 17053 0:100 negligible Negligible SMAO = solid methylaluminoxane

[0128] Table 11 and FIG. 10 show that for transition metal 1/transition metal 2 ratios of 60:40 and 50:50, the activity is significantly higher (when using SMAO/[EBI)ZrCl.sub.2]:[Pn*(H)CrCl.sub.2].sub.2) than the corresponding mixed catalysts in the same molar ratio. This demonstrates a clear synergistic effect at these ratios. For a transition metal 1/transition metal 2 ratio of 75:25 and 40:60, the values for activity are the same within error. AU system compositions that include [Pn*(H)CrCl.sub.2].sub.2 demonstrate a higher activity than the 100:0 molar ratio. Negligible activity was observed when the molar ratio was 0:100 (i.e. no [(EBI)ZrCl.sub.2] was present).

[0129] Given both the interesting activity boost of the tandem systems compared to the traditional zirconium-based systems, and the potential to produce higher value copolymers from a single ethylene feed, new chromium components to the tandem systems were first investigated.

[0130] Using the same methodology, 10 new systems were initially prepared from (EBI)ZrCl.sub.2 and [Cp*CrCl.sub.2].sub.2 or [CpCrCl.sub.2].sub.2, immobilised on solid MAO, based on [Zr]:[Cr] ratios of 0:100, 40:60, 50:50, 40:60 and 75:25, where [Al].sub.MAO/([Cr]+[M]).sub.0=300.

[0131] Ethylene polymerisation runs were carried out using all of the systems using the standard conditions of 10 mg of catalyst, 2 bar ethylene, 1 hour, 60 C., 150 mg TIBA, Hexane (50 mL). The SMAO[Zr][[CpCrCl.sub.2].sub.2] system is compared to SMAO[Zr][[Pn*(H)CrCl.sub.2].sub.2] in FIG. 12.

[0132] The [CpCrCl.sub.2].sub.2-based system clearly outperforms the [Pn*(H)CrCl.sub.2].sub.2-based system at almost all [Zr]:[Cr] ratios (apart from 60:40, where they are the same within error), and catalyst activity increases with decreasing [Zr]:[Cr] ratio up to the point of 40:60. The all chromium system with [Zr]:[Cr] of 0:100 produces negligible amounts of polymer.

[0133] Studies carried out on the [Cp*CrCl.sub.2].sub.2-based system found the peak activity to be at a ratio of 75:25. At this point, this catalyst did indeed outperform the [Pn*(H)CrCl.sub.2].sub.2 system but activity declined after this point with decreasing [Zr]:[Cr] ratio. The importance of the stereolectronics of the chromium complex are clearly illustrated by this result (FIG. 13).

[0134] Another key control experiment to ascertain the role of the chromium in the tandem systems prepared was carried out. LDHMAO-based-catalyst systems were prepared that contained a comparable amount of [Zr] to a particular tandem system but with no [Cr] component (For example, if the tandem system composition was [Al]:[Zr]:[Cr]=100:0.75; 0.25, the the Zr-only analogue prepared was [Al]:[Zr]:[Cr]=100:015:0). Ethylene polymerisation studies were then completed. In these systems, it is important to determine whether with increasing polymerisation activity seen with decreasing [Zr]:[Cr] ratio is a result of the synergistic system itself or more simply a result of the concomitant increase in [Al]:[Zr] ratio. The data are presented in FIG. 14 and compare tandem systems, LDHMAO[Zr]:[Cr], with their [Zr]-only analogues, LDHMAO[Zr].

[0135] The data clearly show that the tandem system is better at all ratios (except for [Zr]:[Cr]=40:60) and that despite the increasing [Al]:[Zr] ratio, the LDHMAO[Zr] catalyst system does not result in an increase in activity. The data again clearly points to the importance of both metals in the tandem systems prepared.

[0136] Gel permeation chromatography data for the LDHMAO- and SMAO[Zr][Cr] systems ([Zr]=(EBIZrCl.sub.2), [Cr]=[(Pn*(H)CrCl.sub.2].sub.2) were recorded and the data, as a function of [Zr]:[Cr] ratio is depicted in FIG. 15. There are significant variations in the molecular weights recorded for the samples produced by LDHMAO[Zr][Cr] systems which are much higher than the samples produced by SMAO[Zr][Cr] systems, which show little effect of varying the [Zr]:[Cr] ratio.

[0137] Fresh samples of sMAO[Zr].sub.60[Cr].sub.40 ([Zr]:[Cr]=60:40) and sMAO[Zr].sub.50[Cr].sub.50 ([Zr]:[Cr]50:50), where [Zr]=(EBI)ZrCl.sub.2 and [Cr]=[Pn*(H)CrCl.sub.2].sub.2, were prepared and tested in a 2 L reactor polymerisation. These complexes represented high activity for the tandem systems and they were chosen for this reason. The productivity data of the polymerisations are summarised in Table 12.

[0138] As expected, productivity increased with increasing pressure and temperature. Interestingly, the system with ratio [Zr]:[Cr]=50:50 outperformed the 60:40 system at 6 and 8 bar of ethylene. Catalyst testing in glass ampoules at 2 bar showed the opposite optimum system.

[0139] Fresh samples of sMAO[Zr].sub.60[Cr].sub.40 ([Zr]:[Cr]=60:40) and sMAO[Zr].sub.50[Cr].sub.50 ([Zr]:[Cr]50:50), where [Zr]=(EBI)ZrCl.sub.2 and [Cr]=[Pn*(H)CrCl.sub.2].sub.2, were prepared and tested in a 2 L reactor polymerisation. These complexes represented high activity for the tandem systems and they were chosen for this reason. The productivity data of the polymerisations are summarised in Table 12.

[0140] As expected, productivity increased with increasing pressure and temperature. Interestingly, the system with ratio [Zr]:[Cr]=50:50 outperformed the 60:40 system at 6 and 8 bar of ethylene. Catalyst testing in glass ampoules at 2 bar showed the opposite optimum system.

[0141] Polymerisation ethylene uptake data was recorded for these runs and an example is shown in FIG. 16. Uptake is high at the ethylene pressure increases but it is also important to note that the uptake remains remarkably stable over the course of 1 hour when quenching occurs.

[0142] Gel permeation chromatography data was collected on the polymers produced by sMAO[Zr].sub.60[Cr].sub.40 and sMAO[Zr].sub.50[Cr].sub.50 at 80 C. and 4, 6 and 8 bar. The data show that the molecular weights (M.sub.w) are significantly higher when the catalyst with an increased [Zr]:[Cr] ratio is used (FIG. 17). The molecular weights also displayed a more general trend of increasing with in Temperature Rising Elution Fractionation (TREF) data was collected in order to better understand the nature of the polymers produced by the tandem systems. The effect of changing pressure at a constant temperature of 80 C. for sMAO[Zr].sub.60[Cr].sub.40 is displayed in FIG. 18. As pressure increases, T.sub.m is observed to increase, suggesting that the relative rate of polymerisation to oligomerisation increases.

[0143] The effect of changing temperature at a constant pressure of 8 bar for sMAO[Zr].sub.60[Cr].sub.40 is displayed in FIG. 19. As temperature increases, T.sub.m increases. Further data over a wider temperature range would need to be collected in order to see if this trend is more widely applicable. creasing ethylene pressure.

[0144] .sup.13C{.sup.1H} NMR spectroscopic data was collected in order to further our understanding of the polymer microstructures obtained. Selected spectra are presented in FIGS. 20 and 21. Both spectra indicate the presence of low levels (up to 0.28% total) of octene and butene incorporation. Despite the low levels, this is very encouraging and is more evidence to confirm that the tandem catalysis system is based on the zirconium centre carrying polymerisation in synergy with the chromium centre carrying out oligomerisation.

[0145] Differential scanning calorimetry (DSC) data was collected on the polymer samples produced by the sMAO[Zr][Cr] systems (FIG. 22). The data show pressure dependent peak temperature values; traces of ethylene/1-hexene copolymers are included for reference.

[0146] The features disclosed in the foregoing description, in the claims and in the accompanying drawings may both separately or in any combination thereof be material for realizing the invention in diverse forms thereof.