Catalyst comprising a metallocene complex and a co-catalyst

Abstract

The invention relates to a metallocene complex according to formula I ##STR00001##
wherein M is a metal selected from lanthanides or transition metals from group 3, 4, 5 or 6 of the Periodic System of the Elements, Q is an anionic ligand to M, k is the number of Q groups and equals the valence of M minus 2, R is a bridging group containing at least one carbon atom bonded to the indenyl moiety at 2-position, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently chosen from the group consisting of H, a halogen atom and a C1-C20 hydrocarbylgroup, and wherein at least one of R.sub.1 and R.sub.2 is not H, and at least one of R.sub.3 and R.sub.4 is not H. The invention also relates to a catalyst comprising the metallocene complex, to a process for making polyolefins and to the use of the polyolefins for making articles.

Claims

1. A metallocene complex according to formula I ##STR00010## wherein M is a metal selected from lanthanides or transition metals from group 3, 4, 5 or 6 of the Periodic System of the Elements, Q is an anionic ligand to M, k is the number of Q groups and equals the valence of M minus 2, R is a bridging group containing at least one carbon atom, selected from a 2,2 biphenylgroup or a substituted 2,2 biphenylgroup, bonded to the indenyl moiety at the 2-position and, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from the group consisting of hydrogen, a halogen atom and a C1-C20 hydrocarbyl group, and wherein at least one of R.sub.1 and R.sub.2 is not hydrogen, and at least one of R.sub.3 and R.sub.4 is not hydrogen.

2. The metallocene complex according to claim 1, wherein M is Ti, Zr or Hf.

3. The metallocene complex according to claim 1, wherein Q is chlorine or a methyl group.

4. The metallocene complex according to claim 1, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from hydrogen, fluorine, chlorine, methyl, ethyl, propyl, or phenyl.

5. A catalyst for polymerizing olefins into polyolefins, wherein the catalyst is formed by reacting a metallocene complex according to claim 1 and a cocatalyst, wherein the cocatalyst is an aluminum or boron containing cocatalyst.

6. The catalyst according to claim 5, wherein the catalyst comprises an inorganic support.

7. A process for polymerizing olefins, which comprises the steps of providing a polymerization reactor, contacting at least one monomer, a metallocene complex as defined in claim 1 and a cocatalyst to prepare a polyolefin under polymerization conditions.

8. The process according to claim 7, wherein at least ethylene and an alfa-olefin are present as monomers to prepare a polyethylene.

9. The catalyst of claim 5, wherein the cocatalyst is an aluminoxane, an aluminum alkyl compound, a trialkylborane, a perfluorophenylborane or a perfluorophenylborate.

10. The catalyst according to claim 9, wherein the catalyst comprises an inorganic support.

11. A process for polymerizing olefins, which comprises the steps of providing a polymerization reactor, contacting at least ethylene and an alfa-olefin as comonomers, a metallocene complex as defined in claim 10 and a cocatalyst to prepare a polyolefin under polymerization conditions.

12. The metallocene complex according to claim 2, wherein Q is chlorine or a methyl group.

13. The metallocene complex according to claim 12, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from hydrogen, fluorine, chlorine, methyl, ethyl, propyl, or phenyl.

14. A catalyst for polymerizing olefins into polyolefins, wherein the catalyst is formed by reacting a metallocene complex according to claim 13 and a cocatalyst, wherein the cocatalyst is an aluminum or boron containing cocatalyst.

15. The catalyst of claim 14, wherein the cocatalyst is an aluminoxane, an aluminum alkyl compound, a trialkylborane, a perfluorophenylborane or a perfluorophenylborate.

16. The catalyst according to claim 14, wherein the catalyst comprises an inorganic support.

17. A process for polymerizing olefins, which comprises the steps of providing a polymerization reactor, contacting at least one monomer, a metallocene complex as defined in claim 14 and a cocatalyst to prepare a polyolefin under polymerization conditions.

18. The process according to claim 7, wherein at least ethylene and an alfa-olefin are present as monomers to prepare a polyethylene.

Description

EXAMPLES

(1) Test Methods

(2) Melt Index

(3) The melt index is measured according to ASTM D-1238-10 Condition F (190 C., 21.6 kg).

(4) Density

(5) The density is determined according to ISO1872-2. The samples were prepared and pressed according to ISO1872-2 and annealed by boiling in water for half an hour, then left to cool for 16 hours in the same water after which the samples were measured.

(6) Molecular Weight Distribution.

(7) Sample Preparation

(8) The polymer samples were dissolved in 1,2,4-trichlorobenzene (TCB) in the concentration range of 0.3-1.3 mg/ml during 4 h at 160 C. and stabilized with 1 g/I di-tertbutylparacresol (DBPC). The solutions were filtered over a 0.45 m filter at high temperature (160 C.) prior to injection.

(9) SEC-DV

(10) The separation of the polymer according to molar mass is performed using an Agilent PL220 Size Exclusion Chromatograph (SEC) equipped with 3 Agilent PL Olexis columns. The SEC system is operated at 160 C. and a flow of 1.0 mL/min. Detectors used are a built-in refractive index detector and a PL BV-400 viscometer

(11) Branches/1000 C

(12) The amount of branches is determined with the aid of FTIR which was calibrated using representative samples that previously have been measured using 13C-NMR.

(13) FTIR of the resulting polymers were measured by converting the PE powder in to a hot-pressed thin film. The film is measured in transmission IR mode. The height of a band corresponding to CH3 bending vibrations (1380-1375 cm-1) is measured and corrected for the film-thickness using 4400-4000 cm-1 spectral region. The obtained value is then compared with a calibration line. The calibration line is established upfront using reference ethylene/1-olefin polymers characterized by 13C NMR.

Synthesis of Metallocene Complexes

(14) 6 different metallocene complexes have been prepared as shown in the next scheme 1:

(15) ##STR00004## ##STR00005##

(16) Catalyst A represents a state of the art catalyst, catalysts B, C, D, E and F represent catalysts according to the present invention.

Example 1: Synthesis of Metallocene Complex D [2,2-Bis(5-4,7-dimethyl-1H-inden-2-yl)biphenyl]zirconium dichloride

Synthesis of 4,7-Dimethylindan-1-one

(17) ##STR00006##

(18) To a stirred suspension of 224 g (1.68 mol) of AlCl.sub.3 in 900 ml of dichloromethane a solution of 186 g (1.5 mol) of 3-chloropropanoyl chloride and 148.4 g (1.4 mol) of p-xylene in 175 ml of dichloromethane was added dropwise over 3 h at room temperature. This mixture was stirred additionally for 2 h at room temperature and then poured on 1000 g of crushed ice. The organic layer was separated, and the aqueous layer was extracted with 3200 ml of dichloromethane. The combined organic extract was washed by aqueous K.sub.2CO.sub.3, dried over K.sub.2CO.sub.3, passed through a short pad of silica gel 60 (40-63 um), and the elute was evaporated to dryness to give 284 g of dark oily liquid. This liquid was added to 2000 ml of 98% sulfuric acid by vigorous stirring at room temperature. Further on, the resulting dark solution was stirred for 1.5 h at 90 C., cooled to room temperature, and then poured on 4000 g of crushed ice in 4000 ml of cold water. Then, 2 liter of dichloromethane was added. The organic layer was separated, and the aqueous layer was extracted with dichloromethane (100 ml per 900 ml of the aqueous phase). The combined organic extract was washed by cold water, aqueous K.sub.2CO.sub.3, dried over K.sub.2CO.sub.3, and finally passed through a pad of silica gel 60 (40-63 um). The obtained elute was evaporated to dryness to give a slightly yellowish solid mass. The obtained crude product was re-crystallized from 500 ml of n-hexane (hot.fwdarw.r.t..fwdarw.0 C., overnight) to give 195 g (87%) of 4,7-dimethylindan-1-one as a white crystalline material. Anal. calc. for C.sub.11H.sub.12O: C, 82.46; H, 7.55. Found: C, 82.77; H, 7.70.

(19) .sup.1H NMR (CDCl.sub.3): 7.22 (d, J=7.5 Hz, 1H), 6.99 (d, J=7.5 Hz, 1H), 2.93 (m, 2H), 2.63 (m, 2H), 2.58 (s, 3H), 2.28 (s, 3H). .sup.13C{.sup.1H} NMR (CDCl.sub.3): 208.18, 154.63, 135.73, 134.23, 134.02, 132.65, 129.05, 36.49, 24.12, 17.81, 17.23.

Synthesis of 2-Bromo-4,7-dimethyl-1H-indene

(20) ##STR00007##

(21) To a solution of 96.1 g (600 mmol) of 4,7-dimethylindan-1-one in 1200 ml of dichloromethane 96 g (601 mmol) of bromine was added dropwise over 1 h. The resulting red solution was stirred overnight at room temperature. The volatiles were removed under vacuum, and the resulting red oily liquid which completely crystallized for a while at room temperature was further used without an additional purification. To a solution of crude 2-bromo-4,7-dimethylindan-1-one in a mixture of 1000 ml of THF and 500 ml of methanol 22.7 g (600 mmol) of NaBH.sub.4 was added portionwise for 3 h at 0-5 C. This mixture was stirred overnight at room temperature and then evaporated to dryness. The residue was acidified by 2 M HCl to pH 5-6, and the formed 2-bromo-4,7-dimethylindan-1-ol was extracted with 3300 ml of dichloromethane. The combined organic extract was dried over Na.sub.2SO.sub.4 and evaporated to dryness. This product was further used without an additional purification. To a solution of thus obtained brown solid in 1400 ml of toluene 15 g of TsOH was added, and the resulting solution was refluxed using Dean-Stark head for 1.5 h. After cooling to room temperature the reaction mixture was washed by 10% aqueous NaHCO.sub.3. The organic layer was separated, and the aqueous layer was additionally extracted with 2100 ml of dichloromethane. The combined organic extract was evaporated to dryness, and the product was isolated by flash-chromatography on silica gel 60 (40-63 um; eluent: hexanes) followed by re-crystallization from n-hexane. This procedure gave 96.7 g (72%) of 2-bromo-4,7-dimethyl-1H-indene as a white crystalline material.

(22) Anal. calc. for C.sub.11H.sub.11Br: C, 59.22; H, 4.97. Found: C, 59.36; H, 5.11.

(23) .sup.1H NMR (CDCl.sub.3): 7.04 (t, J=1.6 Hz, 1H), 6.99 (d, J=7.7 Hz, 1H), 6.91 (d, J=7.7 Hz, 1H), 3.49 (s, 2H), 2.37 (s, 3H), 2.29 (s, 3H). .sup.13C{.sup.1H} NMR (CDCl.sub.3): 142.46, 141.11, 131.61, 129.68, 128.01, 126.94, 126.13, 123.97, 44.75, 18.23, 18.11.

Synthesis of 2,2-Bis(4,7-dimethyl-1H-inden-2-yl)biphenyl

(24) ##STR00008##

(25) A mixture of 17.8 g (80.0 mmol) of 2-bromo-4,7-dimethyl-1H-indene, 9.67 g (43.2 mmol) of dibenzo[c,e][1,2,7]-oxadiborepine-5,7-diol, 18.2 g (172 mmol) of Na.sub.2CO.sub.3, 3.23 g (2.8 mmol, 2.8 mol. %) of Pd[PPh.sub.3].sub.4, 100 ml of water, and 250 ml of 1,2-dimethoxyethane was refluxed for 7 h. The main part of 1,2-dimethoxyethane was distilled off on rotary evaporator. To the residue 400 ml of dichloromethane and 500 ml of water were added. The organic layer was separated, the aqueous layer was additionally extracted with 100 ml of dichloromethane. The combined organic extract was evaporated to dryness, and the residue was partially purified by flash-chromatography on silica gel 60 (40-63 um, 250 g; eluent: hexanes-dichloromethane=1:1). The product-containing fractions were combined and evaporated to dryness to give yellowish mass. It was dissolved in 70 ml of hot chloroform, and 110 ml of n-hexane was added. White needle-like crystals precipitated from this solution for 6 h at room temperature and then overnight at 5 C. were collected, washed with 50 ml of n-hexane, and dried in vacuum. This procedure gave 5.71 g of 2,2-bis(4,7-dimethyl-1H-inden-2-yl)biphenyl. The mother liquor was evaporated to dryness, and the residue was dissolved in 10 ml of hot chloroform followed by an addition of 100 ml of n-hexane. Crystals precipitated from this solution overnight at room temperature were collected and dried in vacuum to give 1.15 g of the title compound. Thus, the total yield of 2,2-bis(4,7-dimethyl-1H-inden-2-yl)biphenyl isolated in this synthesis was 6.86 g (36%).

(26) Anal. calc. for C.sub.34H.sub.30: C, 93.11; H, 6.89. Found: C, 93.04; H, 7.02.

(27) .sup.1H NMR (CDCl.sub.3): 7.44-7.40 (m, 2H), 7.39-7.31 (m, 6H), 6.89 (d, J=7.7 Hz. 2H), 6.79 (d, J=7.7 Hz. 2H), 6.21 (s, 2H), 3.16 (d, J=22.4 Hz. 2H), 2.79 (d, J=22.4 Hz. 2H), 2.10 (s, 6H), 2.07 (s, 6H). .sup.13C{.sup.1H} NMR (CDCl.sub.3): 145.47, 143.58, 141.82, 140.91, 136.45, 130.90, 129.74, 129.05, 128.49, 127.61, 127.47 (two resonances), 127.22, 125.63, 39.91, 18.10, 17.85.

Synthesis of [2,2-Bis(5-4,7-dimethyl-1H-inden-2-yl)biphenyl]zirconium dichloride

(28) ##STR00009##

(29) To a suspension of 11.55 g (26.3 mmol) of 2,2-bis(4,7-dimethyl-1H-inden-2-yl)biphenyl in 450 ml of ether cooled to 60 C. 21.1 ml (52.8 mmol) of 2.5 M.sup.nBuLi in hexanes was added in one portion. This mixture was stirred overnight at room temperature. The resulting slightly yellowish solution with a lot of slightly yellowish precipitate was cooled to 50 C., and 6.14 g (26.4 mmol) of ZrCl.sub.4 was added. The reaction mixture was stirred for 24 h resulting in yellow solution with yellow heavy precipitate. The resulting mixture was evaporated to dryness, and the residue was heated with 900 ml of toluene. This mixture was filtered while hot through glass frit (G4). On the evidence of NMR spectroscopy the filtrate as well as a huge amount of yellow filter cake contained only single organometallic complex, namely [2,2-bis(re-4,7-dimethyl-1H-inden-2-yl)biphenyl]zirconium dichloride, which is hardly soluble in common organic solvents (e.g. ca. 0.5 g per 1000 ml of hot toluene). Crystals precipitated from this filtrate for 12 h at room temperature were collected. The solution separated from the crystals was used in the following repetitive extractions of the desired complex from the filter cake. This procedure was repeated until extraction was complete. The combined yellow crystalline material was dried in vacuum. This procedure gave 12.7 g (81%) of [2,2-bis(re-4,7-dimethyl-1H-inden-2-yl)biphenyl]zirconium dichloride.

(30) Anal. calc. for C.sub.34H.sub.28Cl.sub.2Zr: C, 68.21; H, 4.71. Found: C, 68.40; H, 4.83.

(31) .sup.1H NMR (CDCl.sub.3): 7.86 (dd, J=7.6 Hz, J=1.4 Hz, 2H), 7.57 (m, 4H), 7.45 (dd, J=7.3 Hz, J=1.6 Hz, 2H), 6.95 (d, J=2.8 Hz, 2H), 6.87 (d, J=7.0 Hz, 2H), 6.80 (d, J=7.0 Hz, 2H), 5.38 (d, J=2.8 Hz, 2H), 2.55 (s, 6H), 1.97 (s, 6H).

Example 2: Preparation of the Silica Supported Metallocene Catalyst and its Characterization (I)

(32) The immobilization of the single site catalyst, A-F (Scheme 1) on silica was performed using Incipient Wetness technique and it involves the following steps: 1. MAO (7.6 mL, 30 w %) is added to 0.244 mmol of single site catalyst and the solution is stirred at room temperature for 30 min 2. The MAO/single site catalyst solution is added drop wise to 5.0 g of silica (ES70X, activated at 600 C. for 4 h) while the mixture is stirred mechanically (incipient wetness) 3. The mixture is stirred at 50 C. for 1 h. Volatiles are evaporated in vacuo at 75 C. for 1 h The elemental compositions of the supported catalysts were measured with XRF.

Comparative Experiment A

(33) In order to compare the catalyst performance of the catalysts according to the present invention and a representative state of the art catalysts, Biph (2-Ind).sub.2ZrCl.sub.2 (ref A) was also immobilized on silica using the same protocol mentioned above. Reference patent for state of the art catalyst: U.S. Pat. No. 6,342,622 B1

(34) XRF Results of the Catalysts

(35) TABLE-US-00001 Cat ID Cat Al wt % Si wt % Zr wt % D Biph-(2-IndMe.sub.2).sub.2ZrCl.sub.2 13.5 30.6 0.274 E Biph-(2-IndPh).sub.2ZrCl.sub.2 13.1 30.1 0.292 C Biph-(2-IndCl).sub.2ZrCl.sub.2 12.8 31.0 0.260 B Biph-(2-IndF).sub.2ZrCl.sub.2 13.2 30.9 0.320 Ref A Biph-(2-Ind).sub.2ZrCl.sub.2 12.3 30.1 0.290

(36) All the catalysts have similar elemental compositions.

Example 3: Polymerization and Polymer Characterization

Ethylene/1-Hexene Copolymerization in Suspension (PPR)

(37) PPR Polymerization Protocols

(38) Prior to the execution of a library, the 48 PPR cells (reactors) undergo bake-and-purge cycles overnight (8 h at 90-140 C. with intermittent dry N.sub.2 flow), to remove any contaminants and left-overs from previous experiments. After cooling to glove-box temperature, the stir tops are taken off, and the cells are fitted with disposable 10 mL glass inserts and PEEK stirring paddles (previously hot-dried under vacuum); the stir tops are then set back in place, the cells are loaded with the proper amounts of toluene (in the range 2.0-3.5 mL), 1-hexene (in the range 0.5-2.0 mL) and MAO solution (100 L of 0.1 mol L.sup.1 in toluene), thermostated at 80 C., and brought to the operating pressure of 65 psig with ethylene. At this point, the catalyst injection sequence is started; proper volumes of a toluene chaser, a solution of the precatalyst in toluene (typically in the range 0.01-0.05 mmol L.sup.1), and a toulene buffer are uptaken into the slurry needle, and then injected into the cell of destination. The reaction is left to proceed under stirring (800 rpm) at constant temperature and pressure with continuous feed of ethylene for 30 min, and quenched by over-pressurizing the cell with dry air (preferred to other possible catalyst poisons because in case of cell or quench line leaks oxygen is promptly detected by the dedicated glove-box sensor).

(39) After quenching, the cells are cooled down and vented, the stir-tops are removed, and the glass inserts containing the reaction phase are taken out and transferred to a Genevac EZ2-Plus centrifugal evaporator, where all volatiles are distilled out and the polymers are thoroughly dried overnight. Reaction yields are double-checked against on-line monomer conversion measurements by robotically weighing the dry polymers in a Bohdan Balance Automator while still in the reaction vials (subtracting the pre-recorded tare). Polymer aliquots are then sampled out for the characterizations.

(40) GPC Analysis

(41) GPC curves are recorded with a Freeslate Rapid GPC setup, equipped with a set of 2 mixed-bed Agilent PLgel 10 m columns and a Polymer Char IR4 detector. The upper deck of the setup features a sample dissolution station for up to 48 samples in 10 mL magnetically stirred glass vials, 4 thermostated bays each accommodating 48 polymer solutions in 10 mL glass vials, and a dual arm robot with two heated injection needles. With robotic operation, pre-weighed polymer amounts (typically 1-4 mg) are dissolved in proper volumes of orthodichlorobenzene (ODCB) containing 0.40 mg mL.sup.1 of 4-methyl-2,6-di-tert-butylphenol (BHT) as a stabilizer, so as to obtain solutions at a concentration of 0.5 to 1.0 mg mL.sup.1. After 2 h at 150 C. under gentle stirring to ensure complete dissolution, the samples are transferred to a thermostated bay at 145 C., and sequentially injected into the system at 145 C. and a flow rate of 1.0 mL min.sup.1. In post-trigger delay operation mode, the analysis time is 12.5 min per sample. Calibration is carried out with the universal method, using 10 monodisperse polystyrene samples (Mn between 1.3 and 3700 KDa). Before and after each campaign, samples from a known i-PP batch produced with an ansa-zirconocene catalyst are analyzed for a consistency check.

(42) NMR Characterizations

(43) .sup.13C NMR spectra are recorded with a Bruker Avance 400 III spectrometer equipped with a 5 mm High Temperature Cryoprobe, and a robotic sample changer with pre-heated carousel (24 positions). The samples (20-30 mg) are dissolved at 120 C. in tetrachloroethane-1,2-d.sub.2 (0.6 mL), added with 0.40 mg mL.sup.1 of BHT as a stabilizer, and loaded in the carousel maintained at the same temperature. The spectra are taken sequentially with automated tuning, matching and shimming. Typical operating conditions for routine measurements are: 45 pulse; acquisition time, 2.7 s; relaxation delay, 5.0 s; 400-800 transients (corresponding to an analysis time of 30-60 min). Broad-band proton decoupling is achieved with a modified WALTZ16 sequence (BI_WALTZ16_32 by Bruker).

Ethylene Homopolymerization Procedure in Slurry

(44) The polymerizations were carried out in a 5 L bench scale batch reactor. The reactor operates under slurry conditions using isobutane as diluent. The 5 liter reactor is filled to 65% of its volume with diluent prior to each experiment. Atmer 163 premixed with 2 equivalents of TiBA was used as anti-fouling agent and TiBA was used as scavenger (0.017 mmol/L). The temperature of the reactor was kept as constant as possible by a thermostat bath. About 100 mg of the immobilised catalysts was then injected into the reactor, and constant ethylene pressure was maintained. After 1 hour of reaction time, the polymers were collected and dried in the vacuum oven (60 C., overnight) before the further analysis.

Ethylene/1-Hexene Copolymerization

(45) Copolymerizations were also carried out in the same experimental set up used for homopolymerization. The same polymerization protocols were used except that specific amount of 1-hexene was fed into the reactor prior to the ethylene feed. After 1 hour of reaction time, the polymers were collected and dried in the vacuum oven (60 C., overnight) before the further analysis.

(46) TABLE-US-00002 TABLE 1 Ethylene copolymerization results unsupported catalyst (Solution polymerisation/homogeneous polymerisation) M.sub.w Cat C6 (kg/ C6 ID Catalyst (Vol %) *Rp mol) PDI (mol %) Ref Biph(2-Ind).sub.2ZrCl.sub.2 10 478 386 2.9 1 A Ref Biph(2-Ind).sub.2ZrCl.sub.2 40 160 222 3.0 4.1 A B Biph(2-IndF).sub.2ZrCl.sub.2 10 157 264 2.5 2.1 B Biph(2-IndF).sub.2ZrCl.sub.2 40 34 147 2.2 8.0 C Biph(2-IndCl).sub.2ZrCl.sub.2 10 222 115 2.5 4.4 C Biph(2-IndCl).sub.2ZrCl.sub.2 40 58 124 2.2 8.9 D Biph(2-IndMe.sub.2).sub.2ZrCl.sub.2 10 601 401 2.8 2.0 D Biph(2-IndMe.sub.2).sub.2ZrCl.sub.2 40 136 92 2.2 12.7 *Rp = Productivity in kg mmol.sub.cat.sup.1 [C.sub.2H.sub.4].sup.1 h.sup., Polymerisation time = 30 min, temperature = 80 C., MAO = 2 mM. A = State of the art catalyst
Hexene Incorporation is Higher in the Case of B, C, and D Compared to State of the Art Catalyst A

(47) Ethylene homo and copolymerization results are given in Table 2.

(48) TABLE-US-00003 TABLE 2 Homo and copolymerization results of supported catalysts* 1-hexene Activity MFI Density Branches/ Mw Mn Cat ID (mL) (gPE/gcat) 21.6 Kg/m.sup.3 1000C (kg/mol) (kg/mol) Mw/Mn D 0 1311 2.2 950 240 65 3.8 D 75 2178 2.8 934 1.8 220 67 3.3 E 0 1167 0.92 952 210 59 3.5 E 75 1843 1.6 935 2.3 245 70 3.5 C 75 1104 2.4 933 2.3 190 58 3.3 B 75 1458 3.7 933 2.5 165 48 3.4 Ref A 0 2766 6.6 950 280 63 4.4 Ref A 75 1049 4.6 936 1.6 175 54 3.2 *Polymerization Temperature = 80 C., Polymerization time = 1 hour, isobutane as diluent. Catalyst Ref A represents the comparative example- reference state of the art catalyst.