Method for preparing supported metallocene catalyst, supported metallocene catalyst, and method for preparing polyolefin using the same

Abstract

A supported metallocene catalyst can include a silica-based carrier and an aluminum alkyl halide, a cocatalyst compound, and a metallocene compound supported in the silica-based carrier. The aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than inside the pores, and the cocatalyst compound is supported at higher rate inside the pores of the silica-based carrier than on the surface of the silica-based carrier. Such a supported metallocene catalyst can be prepared by: (i) supporting an aluminum alkyl halide in a silica-based carrier; (ii) supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported; and (iii) supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported. Such a supported metallocene catalyst can be used to polymerize polyolefins with excellent activity and polyolefin with a uniform powder morphology.

Claims

1. A method for preparing a supported metallocene catalyst, comprising steps of: (i) supporting aluminum alkyl halide of the following Chemical Formula 1 in a silica-based carrier; (ii) supporting a cocatalyst compound in the silica-based carrier in which the aluminum alkyl halide is supported; and (iii) supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported, ##STR00009## in the Chemical Formula 1, R.sup.11, R.sup.12, and R.sup.13 are each independently C.sub.1-5 alkyl or halogen, and one or two of the R.sup.11 to R.sup.13 are halogen.

2. The method for preparing a supported metallocene catalyst according to claim 1, wherein the aluminum alkyl halide is one or more compounds selected from the group consisting of dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, and isobutylaluminum dichloride.

3. The method for preparing a supported metallocene catalyst according to claim 1, wherein the step (i) comprises introducing the aluminum alkyl halide in an amount of 0.1 mmol to 20 mmol per unit weight (g) of the silica-based carrier and stirring.

4. The method for preparing a supported metallocene catalyst according to claim 1, wherein the silica-based carrier is one or more compounds selected from the group consisting of silica, silica-alumina, silica-titania, and silica-zirconia.

5. The method for preparing a supported metallocene catalyst according to claim 1, wherein the cocatalyst compound is a compound of the following Chemical Formula 2: ##STR00010## in the Chemical Formula 2, R.sup.21, R.sup.22, and R.sup.23 are each independently hydrogen, halogen, a C.sub.1-20 hydrocarbyl group or a C.sub.1-20 hydrocarbyl group substituted with halogen.

6. The method for preparing a supported metallocene catalyst according to claim 1, wherein the cocatalyst compound is one or more compounds selected from the group consisting of methylaluminoxane, ethylaluminoxane, n-butylaluminoxane, and isobutylaluminoxane.

7. The method for preparing a supported metallocene catalyst according to claim 1, wherein the metallocene compound is one or more compounds selected from the group consisting of a compound of the following Chemical Formula 3 and a compound of the following Chemical Formula 4: ##STR00011## in the Chemical Formulas 3 and 4, R.sup.31, R.sup.32, R.sup.41, and R.sup.42 are each independently hydrogen, halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, C.sub.1-20 alkoxy, or C.sub.2-20 alkoxyalkyl, and X.sup.31, X.sup.32, X.sup.41, and X.sup.42 are each independently halogen or C.sub.1-20 alkyl.

8. The method for preparing a supported metallocene catalyst according to claim 7, wherein the metallocene compound comprises a first metallocene compound of the Chemical Formula 3 and a second metallocene compound of the Chemical Formula 4, and the first metallocene compound and the second metallocene compound are sequentially supported in the silica-based carrier in which the aluminum alkyl halide and the cocatalyst compound are supported.

9. The method for preparing a supported metallocene catalyst according to claim 8, wherein the metallocene compound comprises the first metallocene compound and the second metallocene compound at a mole ratio of 1:0.3 to 1:3.5.

10. A supported metallocene catalyst comprising a silica-based carrier; and aluminum alkyl halide of the following Chemical Formula 1, a cocatalyst compound, and a metallocene compound supported in the silica-based carrier, wherein the aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than inside the pores of the silica-based carrier, and the cocatalyst compound is supported at higher rate inside the pores of the silica-based carrier than on the surface of the silica-based carrier: ##STR00012## in the Chemical Formula 1, R.sup.11, R.sup.12, and R.sup.13 are each independently C.sub.1-5 alkyl or halogen, and one or two of the R.sup.11 to R.sup.13 is halogen.

11. The supported metallocene catalyst according to claim 10, wherein the aluminum alkyl halide is one or more selected from the group consisting of dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, and isobutylaluminum dichloride.

12. The supported metallocene catalyst according to claim 10, wherein the cocatalyst compound is a compound of the following Chemical Formula 2: ##STR00013## in the Chemical Formula 2, R.sup.21, R.sup.22, and R.sup.23 are each independently hydrogen, halogen, a C.sub.1-20 hydrocarbyl group or a C.sub.1-20 hydrocarbyl group substituted with halogen.

13. The supported metallocene catalyst according to claim 10, wherein the metallocene compound is one or more compounds selected from the group consisting of a compound of the following Chemical Formula 3 and a compound of the following Chemical Formula 4: ##STR00014## in the Chemical Formulas 3 and 4, R.sup.31, R.sup.32, R.sup.41, and R.sup.42 are each independently hydrogen, halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, C.sub.1-20 alkoxy, or C.sub.2-20 alkoxyalkyl, and X.sup.31, X.sup.32, X.sup.41, and X.sup.42 are each independently halogen or C.sub.1-20 alkyl.

14. The supported metallocene catalyst according to claim 13, wherein the metallocene compound comprises a first metallocene compound of the Chemical Formula 3 and a second metallocene compound of the Chemical Formula 4.

15. A method for preparing polyolefin comprising a step of polymerizing olefin monomers in the presence of the supported metallocene catalyst according to claim 10 to obtain polyolefin, wherein the polyolefin comprises polyolefin fine with a particle size less than 125 m and polyolefin chunk with a particle size greater than 2.0 mm, respectively in the content of 2 wt % or less.

Description

BRIEF DESCRIPTION OF DRAWING

(1) FIG. 1 is an image of the polyolefin obtained according to Example 7 of the invention taken by a camera and enlarged.

(2) FIG. 2 is an image of the polyolefin obtained according to Comparative Example 3 taken by a camera and enlarged.

DETAILED DESCRIPTION OF THE EMBODIMENTS

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

(4) [Preparation of Supported Metallocene Catalyst]

Example 1

(5) Silica (Grace Davison, SP952) was dehydrated and dried at 200 C. under vacuum for 12 hours.

(6) Into a 2 L SUS high pressure reactor, 50 ml of toluene and 10 g of the silica were introduced, and then, stirred while raising the temperature of the reactor to 40 C. A solution of dimethylaluminum chloride (5 mmol/g-SiO.sub.2)/toluene was introduced thereto, and stirred for 12 hours, and then, decanted.

(7) Subsequently, 53.1 ml of solution of 10 wt % methylaluminoxane (MAO)/toluene (10 mmol/g-SiO.sub.2) was introduced, and stirred for 12 hours.

(8) The temperature of the reactor was raised to 60 C., a solution of the first metallocene compound of the following Chemical Formula 3b (0.01 mmol/g-SiO.sub.2)/toluene was introduced and stirred for 2 hours. Subsequently, a solution of the second metallocene compound of the following Chemical Formula 4a (0.01 mmol/g-SiO.sub.2)/toluene was introduced, and stirred for 2 hours, and then, decanted.

(9) 1 kg of hexane was introduced the reactor and transferred to a filter dry, and the hexane solution was filtered. It was dried at 50 C. for 4 hours to obtain a supported metallocene catalyst.

(10) ##STR00008##

Example 2

(11) A supported metallocene catalyst was obtained by the same method as Example 1, except that a diethylaluminum chloride ((5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Example 3

(12) A supported metallocene catalyst was obtained by the same method as Example 1, except that a diisobutylaluminum chloride ((5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Example 4

(13) A supported metallocene catalyst was obtained by the same method as Example 1, except that a methylaluminum dichloride ((5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Example 5

(14) A supported metallocene catalyst was obtained by the same method as Example 1, except that an ethylaluminum dichloride ((5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Example 6

(15) A supported metallocene catalyst was obtained by the same method as Example 1, except that an isobutylaluminum dichloride ((5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Comparative Example 1

(16) A supported metallocene catalyst was obtained by the same method as Example 1, except that the dimethylaluminum chloride/toluene solution was not used.

(17) Specifically, into a 2 L SUS high pressure reactor, 50 ml of toluene and 10 g of the silica were introduced, and then, stirred while raising the temperature of the reactor to 40 C. Subsequently, 53.1 ml of solution of 10 wt % methylaluminoxane (MAO)/toluene (10 mmol/g-SiO.sub.2) was introduced, and stirred for 12 hours. The temperature of the reactor was raised to 60 C., a solution of the first metallocene compound of the Chemical Formula 3b (0.01 mmol/g-SiO.sub.2)/toluene was introduced and stirred for 2 hours. Subsequently, a solution of the second metallocene compound of the Chemical Formula 4a (0.01 mmol/g-SiO.sub.2)/toluene was introduced, and stirred for 2 hours, and then, decanted. 1 kg of hexane was introduced in the reactor and transferred to a filter dry, and the hexane solution was filtered. It was dried at 50 C. for 4 hours to obtain a supported metallocene catalyst.

Comparative Example 2

(18) The supported metallocene catalyst was obtained by the same method as Example 1, except that the introduction sequence of the dimethylaluminum chloride/toluene solution and the methylaluminoxane (MAO)/toluene solution was inversed.

(19) Specifically, into a 2 L SUS high pressure reactor, 50 ml of toluene and 10 g of the silica were introduced, and then, stirred while raising the temperature of the reactor to 40 C. 53.1 ml of a solution of 10 wt % methylaluminoxane (MAO)/toluene (10 mmol/g-SiO.sub.2) was introduced thereto, and stirred for 12 hours, and then, decanted. Subsequently, a solution of dimethylaluminum chloride (5 mmol/g-SiO.sub.2)/toluene was introduced and stirred for 12 hours. The temperature of the reactor was raised to 60 C., a solution of the first metallocene compound of the Chemical Formula 3b (0.01 mmol/g-SiO.sub.2)/toluene was introduced and stirred for 2 hours. Subsequently, a solution of the second metallocene compound of the Chemical Formula 4a (0.01 mmol/g-SiO.sub.2)/toluene was introduced, and stirred for 2 hours, and then, decanted. 1 kg of hexane was introduced in the reactor and transferred to a filter dry, and the hexane solution was filtered. It was dried at 50 C. for 4 hours to obtain a supported metallocene catalyst.

Comparative Example A

(20) A supported metallocene catalyst was obtained by the same method as Example 1, except that a trimethylaluminum (5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Comparative Example B

(21) A supported metallocene catalyst was obtained by the same method as Example 1, except that a triethylaluminum (5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Comparative Example C

(22) A supported metallocene catalyst was obtained by the same method as Example 1, except that a triisobutylaluminum (5 mmol/g-SiO.sub.2)/toluene solution was used instead of the dimethylaluminum chloride/toluene solution.

Preparation of polyolefin

Example 7

(23) In the presence of the supported metallocene catalyst obtained in Example 1, ethylene was polymerized to prepare polyethylene.

(24) Specifically, 600 ml of an autoclave was vacuum dried, and then, 400 ml of hexane and 10 mg of the supported metallocene catalyst of Example 1 were introduced therein. After raising the temperature of the reactor to 80 C., while introducing ethylene so as to maintain a pressure of 14 kgf/cm.sup.2, the reaction solution was stirred and subjected to a polymerization reaction for 1 hour. After the reaction was completed, it was filtered and dried to obtain polyethylene powder.

Example 8

(25) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Example 2 was used instead of the supported metallocene catalyst of Example 1.

Example 9

(26) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Example 3 was used instead of the supported metallocene catalyst of Example 1.

Example 10

(27) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Example 4 was used instead of the supported metallocene catalyst of Example 1.

Example 11

(28) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Example 5 was used instead of the supported metallocene catalyst of Example 1.

Example 12

(29) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Example 6 was used instead of the supported metallocene catalyst of Example 1.

Comparative Example 3

(30) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Comparative Example 1 was used instead of the supported metallocene catalyst of Example 1.

Comparative Example 4

(31) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Comparative Example 2 was used instead of the supported metallocene catalyst of Example 1.

Comparative Example 5

(32) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Comparative Example 1 was used instead of the supported metallocene catalyst of Example 1, and that dimethylaluminum chloride was added in the polymerization reaction.

(33) Specifically, 600 ml of an autoclave was vacuum dried, and then, 400 ml of hexane, 10 mg of the supported metallocene catalyst of Comparative Example 1 and dimethylaluminum chloride (5 mmol/g-SiO.sub.2)/toluene solution were introduced. After raising the temperature of the reactor to 80 C., while introducing ethylene so as to maintain a pressure of 14 kgf/cm.sup.2, the reaction solution was stirred and subjected to a polymerization reaction for 1 hour. After the reaction was completed, it was filtered and dried to obtain polyethylene powder.

Comparative Example A-1

(34) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Comparative Example A was used instead of the supported metallocene catalyst of Example 1.

Comparative Example B-1

(35) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Comparative Example B was used instead of the supported metallocene catalyst of Example 1.

Comparative Example C-1

(36) Polyethylene powder was obtained by the same method as Example 7, except that the supported metallocene catalyst obtained in Comparative Example C was used instead of the supported metallocene catalyst of Example 1.

Experimental Example

(37) (1) Observation of Polyethylene Powder

(38) The images of polyethylene powders obtained according to Example 7 and Comparative Example 3 taken by a camera and enlarged were shown in FIG. 1 (Example 7) and FIG. 2 (Comparative Example 3).

(39) Referring to FIG. 1, it is confirmed that the polyethylene powder obtained in Example 7 has relatively uniform particle size distribution and most of the particles have smooth shapes.

(40) To the contrary, referring to FIG. 2, it is confirmed that the polyethylene powder obtained in Comparative Example 3 does not have uniform particle size distribution and the particle shape is not smooth. And, in the polyethylene powder obtained in Comparative Example 3, many chunks each having a particle size of 2 mm or more that are not broken by hand were included.

(41) (2) Catalytic Activity (Kg-PE/g-SiO.sub.2)

(42) The weight of the catalyst used in the polymerization reaction and the weight of polyethylene powder obtained from the polymerization reaction were measured to calculate catalytic activity.

(43) (3) Contents of Fine and Chunk in Polymer (Wt %)

(44) Using a sieves (size 850 m, 500 m, 300 m, 125 m), polyethylene powders were separated according to particle size.

(45) Specifically, using the sieves, polyethylene powders were divided into a group having a particle size of 850 m or more; a group of 500 m or more and less than 850 m; a group of 300 m or more and less than 500 m; a group of 125 m or more and less than 300 m; and a group less than 125 m. After measuring the weight of each group, the weight of each group was represented as percentage (wt %) based on the total weight of polyethylene. Among the groups, a group having a particle size less than 125 m was classified as fine.

(46) Additionally, among the group having a particle size of 850 m or more, a group having a particle size greater than 2.0 mm was classified as chunk, and the weight of the chunk was represented as percentage (wt %) based on the total weight of polyethylene.

(47) (4) Particle Size Distribution (PSD)

(48) Using a particle size analyzer (HELOS/KF, Sympatec GmbH), particle sizes of polyethylene powders obtained in Examples and Comparative Examples were analyzed according to the standard measurement method of ISO 13320-1 (Particle size analysis-laser diffraction methods). From the analysis result, a D50 value (m) and a Span value[=(D90D10)/D50] were obtained.

(49) TABLE-US-00001 TABLE 1 Activity (kg-PE/ Chunk Fine D50 PE Catalyst g-SiO.sub.2) (wt %) (wt %) (m) Span Example 7 Example 1 6.3 1.32 0.62 701 0.82 Example 8 Example 2 7.2 1.43 0.92 769 0.84 Example 9 Example 3 6.3 1.61 1.09 722 0.88 Example 10 Example 4 6.4 1.68 0.68 742 0.87 Example 11 Example 5 6.9 1.59 1.10 750 0.90 Example 12 Example 6 6.6 1.67 1.21 745 0.90 Comparative Comparative 7.2 5.50 2.35 787 1.12 Example 3 Example 1 Comparative Comparative 7.1 5.40 2.41 770 1.19 Example 4 Example 2 Comparative Comparative 7.5 6.65 2.91 790 1.37 Example 5 Example 1 + DMAC* Comparative Comparative 6.8 5.75 2.30 780 1.07 Example A-1 Example A Comparative Comparative 7.2 4.77 2.09 798 1.06 Example B-1 Example B Comparative Comparative 7.0 4.94 2.21 774 1.10 Example C-1 Example C DMAC*: dimethylaluminum chloride

(50) Referring to Table 1, it is confirmed hat the supported metallocene catalysts according to Examples exhibit excellent polymerization activities of 6.3 kg-PE/g-SiO.sub.2 or more, and simultaneously, provide polyethylene having remarkably low contents of chunk and fine and a uniform powder morphology.

(51) Meanwhile, it is confirmed that in Comparative Example 3, polymerization activity of the supported metallocene catalyst is excellent, but the contents of chunks and fines are remarkably higher than Examples and powder morphology is inferior.

(52) In Comparative Example 4, like Comparative Example 3, the contents of chunks and fines were high and powder morphology was inferior. Thus, it can be seen that in case the support sequence of aluminum alkyl halide and a cocatalyst compound is inversed, there is little difference from a case wherein aluminum alkyl halide is not introduced.

(53) In Comparative Example 5, polymerization activity was slightly higher than Examples, but powder morphology was very inferior and the contents of chunks and fines were very high. Thus, it can be seen that although introduction of aluminum alkyl halide during the process of polymerization may assist in increasing polymerization activity, it has a bad influence on powder morphology.

(54) In Comparative Examples A-1, B-1, and C-1, polymerization activities were slightly higher than Examples, but powder morphology was deteriorated and the contents of chunks and fines were high. Thus, it can be seen that introduction of a trialkyl aluminum compound instead of aluminum alkyl halide has a bad influence on powder morphology.