Ethylene/alpha-olefin copolymer having excellent processability and surface characteristics

Abstract

The present invention relates to an ethylene/alpha-olefin copolymer. The ethylene/alpha-olefin copolymer according to the present invention has excellent processability and surface characteristics and thus can be usefully applied to various products.

Claims

1. An ethylene/alpha-olefin copolymer having: a weight average molecular weight (g/mol) of 50,000 to 150,000, a molecular weight distribution (Mw/Mn) of 3 to 8, a density (g/cm.sup.3) of 0.940 to 0.970, a diameter of spherulite of 20 m or less, and a half crystallization time of 6 minutes or less measured at 123 C.

2. The ethylene/alpha-olefin copolymer according to claim 1, wherein the polymer chains of the ethylene/alpha-copolymer gathered into bundles to form lamellae, and the spherulite is defined by the three-dimensional growth of the lamellae.

3. The ethylene/alpha-olefin copolymer according to claim 1, wherein the half crystallization time measured at 123 C. is 5 minutes or less.

4. The ethylene/alpha-olefin copolymer according to claim 1, wherein MFRR.sub.2.16 (melt flow index measured at 190 C. under a lead of 2.16 kg according to ASTM D 1238) is 0.5 to 10.

5. The ethylene/alpha-olefin copolymer according to claim 1, wherein MFRR.sub.5/2.16 (value where the melt flow index measured at 190 C. under a load of 5 kg is divided by the melt flow index measured at 190 C. under a lead of 2.16 kg according to ASTM D 1238) is 3 to 8.

6. The ethylene/alpha-olefin copolymer according to claim 1, wherein the alpha-olefin is one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene.

7. The ethylene/alpha-olefin copolymer according to claim 1, wherein the ethylene/alpha-olefin copolymer is produced by polymerizing ethylene and alpha-olefin in the presence of one or more of the first metallocene compounds represented by Chemical formula 1 below; and one or more of the second metallocene compounds selected from the compounds represented by Chemical Formulas 3 to 5 below: ##STR00023## in Chemical Formula 1, A is hydrogen, halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, C.sub.6-20 aryl, C.sub.7-20 alkylaryl, C.sub.7-20 arylalkyl, C.sub.1-20 alkoxy, C.sub.2-20 alkoxyalkyl, C.sub.3-20 heterocycloalkyl, or C.sub.5-20 heteroaryl; D is O, S, N(R) or Si(R)(R) wherein R and R are the same as or different from each other and each independently hydrogen, halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, or C.sub.6-20 aryl; L is C.sub.1-10 linear or branched alkylene; B is carbon, silicon or germanium; Q is hydrogen, halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, C.sub.6-20 aryl, C.sub.7-20alkylaryl or C.sub.7-20 arylalkyl; M is a Group 4 transition metal; X.sup.1 and X.sup.2 are the same as or different from each other and are each independently halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, C.sub.6-20 aryl, nitro, amido, C.sub.1-20 alkylsilyl, C.sub.1-20 alkoxy, or C.sub.1-20 sulfonate; C.sup.1 and C.sup.2 are the same as or different from each other and each independently represented by one of the following chemical formulas 2a, 2b or 2c, provided that cases where both C.sup.1 and C.sup.2 are Chemical Formula 2c, are excluded, ##STR00024## in Chemical Formulas 2a, 2b and 2c, R.sub.1 to R.sub.17 and R.sub.1 to R.sub.9 are same as or different from each other, and are each independently hydrogen, halogen, C.sub.1-20 alkyl, C.sub.2-20 alkenyl, C.sub.1-20 alkylsilyl, C.sub.1-20 silylalkyl, C.sub.1-20 alkoxysilyl, C.sub.1-20 alkoxy, C.sub.6-20 aryl, C.sub.7-20 alkylaryl, or C.sub.7-20 arylalkyl, and adjacent two or more of the R.sub.10 to R.sub.17 are connected to each other to form a substituted or unsubstituted aliphatic or aromatic ring;
(Cp.sup.1R.sup.a).sub.n(Cp.sup.2R.sup.b)M.sup.1Z.sup.1.sub.3-n[Chemical Formula 3] in Chemical Formula 3, M.sup.1 is a Group 4 transition metal; Cp.sup.1 and Cp.sup.2 are the same as or different from each other and are each independently any one selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radicals, which may be substituted with a hydrocarbon having 1 to 20 carbon atoms; R.sup.a and R.sup.b are the same as or different from each other and are each independently hydrogen, C.sub.1-20 alkyl, C.sub.1-10 alkoxy, C.sub.2-20 alkoxyalkyl, C.sub.6-20 aryl, C.sub.6-10 aryloxy, C.sub.2-20 alkenyl, C.sub.7-40 alkylaryl, C.sub.7-40 arylalkyl, C.sub.8-40 arylalkenyl, or C.sub.2-10 alkynyl; Z.sub.1 is a halogen atom, C.sub.1-20 alkyl, C.sub.2-10 alkenyl, C.sub.7-40 alkylaryl, C.sub.7-40 arylalkyl, C.sub.6-20 aryl, substituted or unsubstituted C.sub.1-20 alkylidene, substituted or unsubstituted amino, C.sub.2-20 alkylalkoxy, or C.sub.7-40 arylalkoxy; n is 1 or 0;
(Cp.sup.3R.sup.c).sub.mB.sup.1(Cp.sup.4R.sup.d)M.sup.2Z.sup.2.sub.3-m[Chemical Formula 4] in Chemical Formula 4, M.sup.2 is a Group 4 transition metal; Cp.sup.3 and Cp.sup.4 are the same as or different from each other and are each independently any one selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl and fluorenyl radicals, which may be substituted with a hydrocarbon having 1 to 20 carbon atoms; R.sup.c and R.sup.d are the same as or different from each other and are each independently, hydrogen, C.sub.1-20 alkyl, C.sub.1-10 alkoxy, C.sub.2-20 alkoxyalkyl, C.sub.6-20 aryl, C.sub.6-10 aryloxy, C.sub.2-20 alkenyl, C.sub.7-40 alkylaryl, C.sub.7-40 arylalkyl, C.sub.8-40 arylalkenyl, or C.sub.2-10 alkynyl; Z.sup.2 is a halogen atom, C.sub.1-20 alkyl, C.sub.2-10 alkenyl, C.sub.7-40 alkyl aryl, C.sub.7-40 arylalkyl, C.sub.6-20 aryl, substituted or unsubstituted C.sub.1-20 alkylidene, substituted or unsubstituted amino, C.sub.2-20 alkylalkoxy, or C.sub.7-40 arylalkoxy; B.sup.1 is at least one of carbon, germanium, silicon, phosphorus, or nitrogen atom containing radicals, which cross-link Cp.sup.3R.sup.c ring and Cp.sup.4R.sup.d ring or which cross-link one Cp.sup.4R.sup.d ring to M.sup.2, a combination thereof; m is 1 or 0;
(Cp.sup.5R.sup.e)B.sup.2(J)M.sup.3Z.sup.3.sub.2[Chemical Formula 5] in Chemical Formula 5, M.sup.3 is a Group 4 transition metal; Cp.sup.5 is any one selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl and fluorenyl radicals, which may be substituted with a hydrocarbon having 1 to 20 carbon atoms; R.sup.e is hydrogen, C.sub.1-20 alkyl, C.sub.1-10 alkoxy, C.sub.2-20 alkoxyalkyl, C.sub.6-20 aryl, C.sub.6-10 aryloxy, C.sub.2-20 alkenyl, C.sub.7-40 alkylaryl, C.sub.7-40 arylalkyl, C.sub.8-40 arylalkenyl, or C.sub.2-10 alkynyl; Z.sup.3 is a halogen atom, C.sub.1-20 alkyl, C.sub.2-10 alkenyl, C.sub.7-40 alkylaryl, C.sub.7-40 arylalkyl, C.sub.6-20 aryl, substituted or unsubstituted C.sub.1-20 alkylidene, substituted or unsubstituted amino, C.sub.2-20 alkylalkoxy, or C.sub.7-40 arylalkoxy; B.sup.2 is at least one of carbon, germanium, silicon, phosphorus, or nitrogen atom containing radicals, which cross-link Cp.sup.5R.sup.e ring and J, or a combination thereof; J is any one selected from the group consisting of NR.sup.f, O, PR.sup.f and S, and the R.sup.f is C.sub.1-20 alkyl, aryl, substituted alkyl or substituted aryl.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an observed image of the spherulite of the polymer prepared in one example of the present invention.

(2) FIGS. 2 and 3 show observed images of the spherulite of the polymer prepared in a comparative example of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(3) Hereinafter, preferred Examples are provided for better understanding of the present invention. However, these Examples are for illustrative purposes only and the invention are not intended to be limited by these Examples.

Preparation Example 1

(4) Step 1) Preparation of a Ligand Compound

(5) 2 g of fluorene was dissolved in 5 mL of MTBE and 100 mL of hexane, and 5.5 mL of 2.5 M n-BuLi hexane solution was added dropwise in a dry ice/acetone bath and stirred overnight at room temperature. 3.6 g of (6-(tert-butoxy)hexyl)dichloro(methyl)silane was dissolved in 50 mL of hexane, and fluorene-Li slurry was transferred under a dry ice/acetone bath for 30 minutes and stirred overnight at room temperature. At the same time, 5,8-dimethyl-5,10-dihydroindeno[1,2-b]indole (12 mmol, 2.8 g) was dissolved in 60 mL of THF, and 5.5 mL of 2.5 M n-BuLi hexane solution was added dropwise in a dry ice/acetone bath and stirred overnight at room temperature. The reaction solution of fluorene and (6-(tert-butoxy)hexyl)dichloro(methyl)silane was subjected to NMR sampling to confirm the completion of the reaction, and then 5,8-dimethyl-5,10-dihydroindeno[1,2-b]indole-Li solution was transferred under dry ice/acetone bath. The mixture was stirred overnight at room temperature. After reaction, the reaction mixture was extracted with ether/water and the remaining moisture in the organic layer was removed with MgSO.sub.4 to give the ligand compound (Mw 597.90, 12 mmol), and it could be confirmed by 1H-NMR that two isomers were produced.

(6) .sup.1H NMR (500 MHz, d.sub.6-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)

(7) Step 2) Preparation of Metallocene Compound

(8) 7.2 g (12 mmol) of the ligand compound synthesized in the step 1 was dissolved in 50 mL of diethylether, and 11.5 mL of 2.5 M n-BuLi hexane solution was added dropwise in a dry ice/acetone bath and stirred overnight at room temperature. The mixture was dried under vacuum to give sticky oil having a brown color. This oil was dissolved in toluene to give a slurry. ZrCl.sub.4(THF).sub.2 was prepared, and toluene (50 mL) was added thereto to prepare a slurry. The toluene slurry of ZrCl.sub.4(THF).sub.2 (50 mL) was transferred in a dry ice/acetone bath. As the mixture was stirred overnight at room temperature, the color was changed to violet. The reaction solution was filtered to remove LiCl. The filtrate was dried under vacuum to remove toluene, hexane was added thereto, and the mixture was sonicated for 1 hour. The slurry was filtered to give 6 g of metallocene compound (Mw 758.02, 7.92 mmol, yield 66 mol %) having a dark violet color as a filtered solid. Two isomers were observed through .sup.1H-NMR.

(9) .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 2

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

(11) Also, t-Butyl-O(CH.sub.2).sub.6C.sub.5H.sub.5 was dissolved in THF at 78 C., n-BuLi was slowly added thereto, and the mixture was warmed up to room temperature and then reacted for 8 hours. Again at a temperature of 78 C., thus prepared lithium salt solution was slowly added to a suspension solution of ZrCl.sub.4(THF).sub.2 (1.70 g, 4.50 mmol)/THF (30 mL) and the mixture was further reacted at room temperature for 6 hours.

(12) All volatile substances were dried under vacuum and hexane solvent was added to the resulting oily liquid substance, which was then filtered. The filtrate was dried under vacuum, and hexane was added to induce a precipitate at a low temperature (20 C.). The resulting precipitate was filtered at a low temperature to give [tBu-O(CH.sub.2).sub.6C.sub.5H.sub.4].sub.2ZrCl.sub.2 compound (yield 92%) as a white solid.

(13) .sup.1H NMR (300 MHz, CDCl.sub.3): 6.28 (t, J=2.6 Hz, 2H), 6.19 (t, J=2.6 Hz, 2H), 3.31 (t, 6.6 Hz, 2H), 2.62 (t, J=8 Hz), 1.7-1.3 (m, 8H), 1.17 (s, 9H).

(14) .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.

Preparation Example 3

(15) Step 1) Drying of Support

(16) Silica (SYLOPOL 948 manufactured by Grace Davison Co.) was dehydrated at a temperature of 400 C. for 15 hours in a vacuum state.

(17) Step 2) Preparation of Supported Support

(18) 10 g of the dried silica of the step 1 was introduced to a glass reactor to which 100 mL of toluene was additionally added and stirred. 50 mL of 10 wt % methylaluminoxane (MAO)/toluene solution was added thereto, and the mixture was slowly reacted while stirring at 40 C. Thereafter, the reaction solution was washed with a sufficient amount of toluene to remove an unreacted aluminum compound, and the remaining toluene was removed under reduced pressure. 100 mL of toluene was added thereto again, to which 0.25 mmol of the metallocene catalyst prepared in Preparation Example 1 dissolved in toluene was added together and reacted for 1 hour. After completion of the reaction, 0.25 mmol of the metallocene catalyst prepared in Preparation Example 2 dissolved in toluene was added and further reacted for 1 hour. After completion of the reaction, the stirring was stopped and the toluene was removed by layer separation, to which 1.0 mmol of anilinium borate (N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, AB) was added and stirred for 1 hour. Toluene was then removed at 50 C. under reduced pressure to give the supported catalyst.

Example 1: Ethylene/Alpha-Olefin Copolymer

(19) 50 mg of the supported catalyst prepared in Preparation Example 3 was weighed in a dry box and introduced to a 50 mL glass bottle. The bottle was sealed with a rubber diaphragm and taken out of the dry box to prepare a catalyst for injection. The polymerization was performed in a 2 L metal alloy reactor equipped with a mechanical stirrer and capable of controlling temperature and being used under high pressure.

(20) 1 L of hexane containing 1.0 mmol of triethylaluminum, and 1-hexene (5 mL) were introduced to the reactor, and then the prepared supported catalyst was introduced thereto without contact with air. Then, the polymerization was carried out for an hour at 80 C., while continuously providing a gaseous ethylene monomer under a pressure of 9 Kgf/cm.sup.2. The polymerization was terminated by stopping the stirring and then exhausting ethylene. After most of the polymerization solvent thus obtained was filtered off, the resulting polymer was dried at 80 C. vacuum oven for 4 hours.

Example 2: Ethylene/Alpha-Olefin Copolymer

(21) An ethylene/alpha-olefin copolymer was prepared in the same manner as in Example 1, except that the addition amount of 1-hexene was less than 5 mL.

Comparative Example

(22) The following products were used as comparative examples.

(23) Comparative Example 1: 2010 J (Lotte Chemical)

(24) Comparative Example 2: LUTENE-H ME 8000 (LG Chem)

(25) Comparative Example 3: Rigidex HD 6070 UA (INEOS)

Experiment & Example: Evaluation of Physical Properties of Polymer

(26) The polymers prepared in the above Examples and Comparative Examples were evaluated for physical properties in the following manners.

(27) 1) Density: ASTM 1505

(28) 2) Melt Flow index (MFR, 5 kg/2.16 kg): measurement temperature 190 C., ASTM D1238

(29) 3) MFRR (MFR.sub.5/MFR.sub.2.16): the ratio where MFR.sub.5 melt index (MI, load: 5 kg) is divided by MFR.sub.2.16 (MI, load: 2.16 kg).

(30) 4) Mn, Mw, MWD, GPC curve: The sample was melted and pre-treated in 1,2,4-trichlorobenzene containing BHT 0.0125% using PL-SP260 at 160 C. for 10 hours, and the number average molecular weight and the weight average molecular weight were measured at a temperature of 160 C. using PL-GPC220. The molecular weight distribution was indicated by the ratio of the weight average molecular weight and the number average molecular weight.

(31) 5) Size of spherulite: The surface of the sample was observed with a microscope. Specifically, the diameter of the spherulite was measured after the ethylene/alpha-olefin copolymer was completely melted at 190 C. and then reached the crystallization temperature at a speed of 10 C./min. Herein, the diameter of the spherulite is the size when each spherulite overlaps according to the growth of the spherulite.

(32) 6) Half crystallization time (T at 123 C.): The half crystallization time was measured using a differential scanning calorimetry (DSC), and is the time when it is a half of the peak value in the heat quantity that appears after the ethylene/alpha-olefin copolymer is completely melted at 190 C., quenched (80 C./min) up to a crystallization temperature (123 C.).

(33) The results are shown in Table 1 below. In addition, the observation results of the spherulite of each copolymer are shown in FIGS. 1 to 3.

(34) TABLE-US-00001 TABLE 1 Compar- Compar- Compar- ative ative ative Example Example Example Example Example Unit 1 2 1 2 3 Density g/cm.sup.3 0.962 0.957 0.956 0.957 0.955 MI.sub.2.16 5 7.52 6.94 8.04 7.27 MFRR(MI.sub.5/MI.sub.2.16) 3.88 3.58 2.62 2.87 2.89 Molecular weight g/mol 8.6 8.2 6.9 7.3 8.0 (MW, 10.sup.4) Molecular weight 5.14 3.96 2.54 5.18 4.53 distribution(MWD) Presence of LCB X X X Size of spherulite Mm <20 <20 >20 >20 >20 T.sub.1/2 at 123 C. Min 2.5 4.1 1.8 8.9 9.2

(35) As shown in Table 1 above, it was confirmed that the size of the spherulite of Examples according to the present invention was less than 20 m, while the size of the spherulite of Comparative Examples exceeded 20 m. It was also confirmed that the half crystallization speed was significantly faster than that of Comparative Example 3 having a molecular weight and a molecular weight distribution similar to those of Examples of the present invention.