Supported hybrid catalyst system for ethylene slurry polymerization and method for preparing ethylene polymer with the catalyst system

Abstract

The present invention relates to a supported hybrid catalyst system for ethylene slurry polymerization and a method for preparing ethylene polymer therewith. The supported hybrid catalyst system according to the present invention may exhibit high activity during ethylene slurry polymerization, and enables preparation of an ethylene polymer having a narrow molecular weight distribution but excellent processability.

Claims

1. A supported hybrid catalyst system for ethylene slurry polymerization, comprising a carrier and three or more kinds of metallocene compounds supported on the carrier, wherein the three or more kinds of metallocene compounds comprise at least one metallocene compound having the following structural formula: ##STR00027## at least one metallocene compound represented by the following structural formula: ##STR00028## and at least one metallocene compound selected from the group consisting of compounds represented by the following structural formulas: ##STR00029##

2. The supported hybrid catalyst system for ethylene slurry polymerization according to claim 1, wherein the supported hybrid catalyst system further comprises one or more cocatalysts selected from the group consisting of compounds represented by the following Chemical Formulas 7 to 9:
[Al(R.sup.71)O].sub.c[Chemical Formula 7] wherein, in Chemical Formula 7, c is an integer of 2 or more; and each R.sup.71 is each independently a halogen, or a C1-20 hydrocarbyl or C1-20 hydrocarbyl substituted with a halogen,
D(R.sup.81).sub.3[Chemical Formula 8] wherein, in Chemical Formula 8, D is aluminum or boron; and each R.sup.81 is independently a halogen, or a C1-20 hydrocarbyl or C1-20 hydrocarbyl group substituted with a halogen,
[L-H].sup.+[Q(E).sub.4].sup.[Chemical Formula 9] wherein, in Chemical Formula 9, L is a neutral Lewis base; [L-H].sup.+ is a Bronsted acid; Q is boron or aluminum in an oxidation state of +3; and each E is independently a halogen having a hydrogen valence of one or more, or a C6-20 aryl or C1-20 alkyl unsubstituted or substituted with a C1-20 hydrocarbyl, alkoxy, or phenoxy functional group.

3. The supported hybrid catalyst system for ethylene slurry polymerization according to claim 2, wherein the cocatalyst is one or more selected from the group consisting of trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, triisobutyl aluminum, ethylaluminum sesquichloride, diethylaluminum chloride, ethyl aluminum dichloride, methylaluminoxane, and modified methylaluminoxane.

4. A method for preparing an ethylene polymer, comprising the step of slurry polymerization of olefin monomers including ethylene in the presence of the supported hybrid catalyst system according to claim 1.

5. The method for preparing an ethylene polymer according to claim 4, wherein the ethylene polymer has a weight average molecular weight (Mw) of 50,000 to 150,000, a polydispersity index of 2.5 to 3.5, a melt index of 7.0 to 8.5 g/10 min (190 C., 2.16 kg), and a spiral flow of 20 to 30 cm measured according to ASTM D 3123-09.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Hereinafter, preferable examples will be presented for better understanding of the present invention. However, these examples are presented only as illustrations of the invention, and the present invention is not limited thereby.

Preparation Example 1

(2) ##STR00023##

(3) A metallocene compound of the above structural formula, dichloro[rac-ethylene bis(indenyl)]zirconium(IV), was prepared (purchased from Sigma-Aldrich, CAS Number 100080-82-8).

Preparation Example 2

(4) ##STR00024##

(5) t-butyl-O(CH.sub.2).sub.6Cl was prepared using 6-chlorohexanol by a method described in the document Tetrahedron Lett. 2951 (1988), and NaCp was reacted therewith to obtain t-butyl-O(CH.sub.2).sub.6C.sub.6H.sub.6 (yield 60%, b.p. 80 C./0.1 mmHg).

(6) Further, at 78 C., t-butyl-O(CH.sub.2).sub.6C.sub.6H.sub.6 was dissolved in THF, and n-BuLi was slowly added thereto, followed by a temperature rise to room temperature and reaction for 8 hours. The synthesized lithium salt solution was slowly added to a suspension of ZrCl.sub.4(THF).sub.2 (1.70 g, 4.50 mmol)/THF (30 ml) at 78 C., and the solution was additionally reacted at room temperature for 6 hours.

(7) All the volatile materials were vacuum dried, and a hexane solvent was added to the obtained oily liquid to filter it. The filtered solution was vacuum dried, and then hexane was added to induce precipitation at a low temperature (20 C.). The obtained precipitate was filtered at a low temperature to obtain a compound [tBu-O(CH.sub.2).sub.6C.sub.6H.sub.4].sub.2ZrCl.sub.2 in the form of a white solid (yield 92%).

(8) .sup.1H NMR (300 MHz, CDCl.sub.3): 6.28 (t, J=2.6 Hz, 2H), 6.19 (t, J=2.6 Hz, 2H), 3.21 (t, 6.6 Hz, 2H), 2.62 (t, J=8 Hz), 1.7-1.3 (m, 8H), 1.17 (s, 9H).

(9) .sup.13C NMR (CDCl.sub.3): 135.09, 116.66, 112.28, 72.42, 61.52, 30.66, 30.61, 30.14, 29.18, 27.58, 26.00.

Precipitation Example 3

(10) ##STR00025##

(11) (Preparation of a Ligand Compound)

(12) 2 g of fluorene was dissolved in 5 mL MTBE and 100 mL of hexane, 5.5 mL of a 2.5M n-BuLi solution in hexane was added dropwise in a dry ice/acetone bath, and the solution was stirred at room temperature overnight. 3.6 g of (6-(tert-butoxy)hexyl)dichloro(methyl)silane was dissolved in 50 mL of hexane, the fluorene-Li slurry was transferred thereto under a dry ice/acetone bath for 30 minutes, and the solution was stirred at room temperature overnight.

(13) Simultaneously, 5,8-dimethyl-5,10-dihydroindeno[1,2-b]indole (12 mmol, 2.8 g) was also dissolved in 60 mL of THF, 5.5 mL of a 2.5M n-BuLi solution in hexane was added dropwise in a dry ice/acetone bath, and the solution was stirred at room temperature overnight. By NMR sampling of the reaction solution of fluorene and (6-(tert-butoxy)hexyl)dichloro(methyl)silane, the completion of the reaction was confirmed, and then the dimethyl-5,10-dihydroindeno[1,2-b]indole-Li solution was transferred thereto under a dry ice/acetone bath. The solution was stirred at room temperature overnight.

(14) After the reaction, the solution was extracted with ether/water, and the remaining moisture in the organic layer was removed with MgSO.sub.4, thus obtaining a ligand compound (Mw 597.90, 12 mmol). Two isomers were observed in .sup.1H-NMR.

(15) .sup.1H NMR (500 MHz, d6-benzene): 0.300.18 (3H, d), 0.40 (2H, m), 0.651.45 (8H, m), 1.12 (9H, d), 2.362.40 (3H, d), 3.17 (2H, m), 3.413.43 (3H, d), 4.174.21 (1H, d), 4.344.38 (1H, d), 6.907.80 (15H, m).

(16) (Preparation of a Metallocene Compound)

(17) 7.2 g (12 mmol) of the above-prepared ligand compound was dissolved in 50 mL of diethylether, 11.5 mL of a 2.5 M n-BuLi solution in hexane was added dropwise in a dry ice/acetone bath, and the solution was stirred at room temperature overnight. The solution was vacuum dried to obtain a sticky oil of a brown color. It was dissolved in toluene to obtain a slurry.

(18) ZrCl.sub.4(THF).sub.2 was prepared, and 50 mL of toluene was added to prepare a slurry. The 50 mL toluene slurry of ZrCl.sub.4(THF).sub.2 was transferred in a dry ice/acetone bath. As the solution was stirred at room temperature overnight, it was turned into a violet color. The reaction solution was filtered to remove LiCl. Toluene in the filtrate was removed by vacuum drying, and then hexane was added, and the solution was sonicated for 1 hour.

(19) The slurry was filtered to obtain 6 g of filtered solid, a dark violet metallocene compound (Mw 758.02, 7.92 mmol, yield 66 mol %). Two isomers were observed in .sup.1H-NMR.

(20) .sup.1H NMR (500 MHz, CDCl.sub.3): 1.19 (9H, d), 1.71 (3H, d), 1.501.70 (4H, m), 1.79 (2H, m), 1.982.19 (4H, m), 2.58 (3H, s), 3.38 (2H, m), 3.91 (3H, d), 6.667.88 (15H, m).

Preparation Example 4

(21) ##STR00026##

(22) A metallocene compound of the above chemical formula was prepared.

Example 1

(23) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(24) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(25) Again, 100 mL of toluene was introduced, and then 0.25 mmol of the metallocene compound prepared in Preparation Example 1 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour. After the reaction was finished, 0.25 mmol of the metallocene compound prepared in Preparation Example 2 was dissolved in toluene and introduced, and the solution was additionally reacted for 1 hour.

(26) After the reaction was finished, stirring was stopped, and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced, the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Example 2

(27) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(28) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(29) Again, 100 mL of toluene was introduced, and then 0.25 mmol of the metallocene compound prepared in Preparation Example 1 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour. After the reaction was finished, 0.125 mmol of the metallocene compound prepared in Preparation Example 2 was dissolved in toluene and introduced, and then the solution was additionally reacted for 1 hour. After the reaction was finished, 0.125 mmol of the metallocene compound prepared in Preparation Example 3 was dissolved in toluene and introduced, and the solution was additionally reacted for 1 hour.

(30) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Example 3

(31) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(32) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(33) Again, 100 mL of toluene was introduced, and then, 0.25 mmol of the metallocene compound prepared in Preparation Example 1 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour. After the reaction was finished, 0.25 mmol of the metallocene compound prepared in Preparation Example 3 was dissolved in toluene and introduced, and the solution was additionally reacted for 1 hour.

(34) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Comparative Example 1

(35) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(36) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(37) Again, 100 mL of toluene was introduced, 0.25 mmol of the metallocene compound prepared in Preparation Example 4 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour. After the reaction was finished, 0.25 mmol of the metallocene compound prepared in Preparation Example 2 was dissolved in toluene and introduced, and then the solution was additionally reacted for 1 hour.

(38) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Comparative Example 2

(39) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(40) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(41) Again, 100 mL of toluene was introduced, 0.25 mmol of the metallocene compound prepared in Preparation Example 4 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour. After the reaction was finished, 0.125 mmol of the metallocene compound prepared in Preparation Example 2 was dissolved in toluene and introduced, and the solution was additionally reacted for 1 hour. After the reaction was finished, 0.125 mmol of the metallocene compound prepared in Preparation Example 3 was dissolved in toluene and introduced, and then the solution was additionally reacted for 1 hour.

(42) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Comparative Example 3

(43) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(44) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(45) Again, 100 mL of toluene was introduced, 0.25 mmol of the metallocene compound prepared in Preparation Example 2 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour. After the reaction was finished, 0.25 mmol of the metallocene compound prepared in Preparation Example 3 was dissolved in toluene and introduced, and the solution was additionally reacted for 1 hour.

(46) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Comparative Example 4

(47) A Ziegler-Natta catalyst (Sigma-Aldrich) was prepared.

Comparative Example 5

(48) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(49) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(50) Again, 100 mL of toluene was introduced, 0.5 mmol of the metallocene compound prepared in Preparation Example 1 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour.

(51) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Comparative Example 6

(52) Silica (manufactured by Grace Davison, SYLOPOL 948) was dehydrated at 400 C. for 15 hours under vacuum.

(53) 10 g of dried silica was put in a glass reactor, 100 mL of toluene was additionally put therein, and the solution was stirred. 50 mL of a 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the solution was slowly reacted at 40 C. while stirring. Thereafter, it was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed by pressure reduction.

(54) Again, 100 mL of toluene was introduced, 0.5 mmol of the metallocene compound prepared in Preparation Example 4 was dissolved in toluene and introduced together, and the solution was reacted for 1 hour.

(55) After the reaction was finished, stirring was stopped and the toluene layer was separated and removed, 1.0 mmol of anilinium borate (N, N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was introduced and the solution was stirred for 1 hour, and toluene was removed by pressure reduction at 50 C., thus preparing a supported catalyst.

Experimental Example 1

(56) The slurry polymerization of ethylene was conducted in the presence of each supported catalyst prepared in the examples and comparative examples, thus obtaining an ethylene homopolymer.

(57) Specifically, 50 mg of each supported catalyst prepared in Examples 1 to 3 and Comparative Examples 1 to 6 was quantified in a dry box and each was put in a 50 mL glass bottle, which was then sealed with a rubber septum and taken out of the dry box, thus preparing a catalyst to be introduced. Polymerization was conducted in a 2 L metal alloy reactor equipped with a mechanical stirrer and used under high pressure, of which temperature could be controlled.

(58) Into the reactor, 1 L of hexane containing 1.0 mmol triethylaluminum was introduced, and each supported catalyst prepared above was introduced into the reactor without air contact, and then, at 80 C., gaseous ethylene monomers were continuously added at a pressure of 9 kgf/cm.sup.2 and polymerized for 1 hour. After stirring was stopped, ethylene was exhausted and removed, thus finishing polymerization.

(59) After removing most of the polymerization solvents by filtration, the obtained polymer was dried in a vacuum oven at 80 C. for 4 hours.

Experimental Example 2

(60) For the ethylene polymers prepared according to Experimental Example 1, the properties were measured as follows, and the results are shown in the following Table 1.

(61) (1) Catalytic Activity (Kg PE/g SiO.sub.2)

(62) The catalytic activity was calculated as a ratio of the weight (kg PE) of the polymer produced per catalyst content (g SiO.sub.2) used per unit time (h).

(63) (2) Molecular Weight (Mw), Polydispersity Index (PDI), and Density (D) of Polymer

(64) Using nGPC, the weight average molecular weight (Mw), number average molecular weight (Mn), and density of the polymer were measured. The polydispersity index (PDI) was calculated by dividing the obtained Mw by Mn.

(65) (3) Melt Index (MI) of Polymer

(66) The melt index (MI2.16) was measured at 190 C. under a load of 2.16 kg according to ASTM D 1238, and it was indicated as the weight (g) of the polymer melted in 10 minutes. Further, the melt index (MI10) was measured at 190 C. under a load of 10 kg according to ASTM D 1238, and it was indicated as the weight (g) of the polymer melted in 10 minutes. The obtained MI10 was divided by MI2.16, thus showing the ratio (MFRR).

(67) (4) Spiral Flow (SF, Cm)

(68) Spiral flow of the polymer was measured according to ASTM D 2123-09.

(69) TABLE-US-00001 TABLE 1 Precursor Activity MI2.16 D (Preparation (kg PE/g Mw (g/10 (g/ SF Example) SiO.sub.2) (g/mol) PDI min) MFRR cm.sup.3) (cm) Example 1 1 + 2 33 74000 2.8 8.0 3.5 0.956 24 Example 2 1 + 2 + 3 31 83000 3.1 7.7 3.3 0.955 23 Example 3 1 + 3 27 79000 3.0 7.7 3.4 0.956 23 Comparative 4 + 2 20 78000 3.2 5.6 3.1 0.957 21 Example 1 Comparative 4 + 2 + 3 19 83000 3.2 4.9 3.1 0.956 21 Example 2 Comparative 2 + 3 20 82000 3.4 7.5 3.0 0.957 20 Example 3 Comparative Z/N 18 72000 4.8 7.5 1.6 0.957 18 Example 4 Comparative 1 10 10000 1.0 20.1 2.5 0.955 38 Example 5 Comparative 4 7 15000 1.4 15.0 3.1 0.955 34 Example 6

(70) Referring to Table 1, it was confirmed that the supported hybrid catalyst systems of Examples 1 to 3 exhibit remarkably higher polymerization activities, compared to the catalyst systems of Comparative Examples 1 to 6.

(71) Particularly, the supported hybrid catalyst systems of Examples 1 to 3 can provide an ethylene polymer that has a high molecular weight and a narrow molecular weight distribution but has excellent processability.