Olefin-based polymer

Abstract

The present invention relates to an olefin-based polymer, which has (1) a density (d) ranging from 0.850 to 0.865 g/cc, (2) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 0.1 g/10 min to 3.0 g/10 min, and (3) a soluble fraction (SF) of 10 wt % or more at −20° C. in cross-fractionation chromatography (CFC), in which a weight average molecular weight (Mw) of the soluble fraction is in a range of 50,000 g/mol to 500,000 g/mol. The olefin-based polymer according to the present invention exhibits improved anti-blocking properties as a low-density olefin-based polymer.

Claims

1. An olefin-based polymer, which has (1) a density (d) ranging from 0.850 to 0.865 g/cc, (2) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 0.1 g/10 min to 3.0 g/10 min, and (3) a soluble fraction (SF) of 8 wt % or more at −20° C. in cross-fractionation chromatography (CFC), in which a weight average molecular weight (Mw) of the soluble fraction is in a range of 50,000 g/mol to 500,000 g/moL, wherein the soluble fraction is measured by using o-dichlorobenzene as a solvent.

2. The olefin-based polymer according to claim 1, wherein the weight average molecular weight (Mw) of the soluble fraction of the olefin-based polymer at −20° C. in cross-fractionation chromatography is in a range of 50,000 g/mol to 300,000 g/mol.

3. The olefin-based polymer according to claim 1, wherein the weight average molecular weight (Mw) of the soluble fraction of the olefin-based polymer at −20° C. in cross-fractionation chromatography is in a range of 60,000 g/mol to 200,000 g/mol.

4. The olefin-based polymer according to claim 1, wherein the olefin-based polymer has (4) a molecular weight distribution (MWD) in a range of 1.0 to 3.0.

5. The olefin-based polymer according to claim 1, wherein the olefin-based polymer has (5) a weight average molecular weight (Mw) in a range of 10,000 to 500,000.

6. The olefin-based polymer according to claim 1, wherein the olefin-based polymer has the (2) melt index (MI) in a range of 0.2 g/10 min to 2 g/10 min.

7. The olefin-based polymer according to claim 1, wherein the olefin-based polymer is a copolymer of ethylene and an alpha-olefin comonomer having 3 to 12 carbon atoms.

8. The olefin-based polymer according to claim 7, wherein the alpha-olefin comonomer includes any one 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, 1-eicosene, norbornene, norbornadiene, ethylidene norbornene, phenyl norbornene, vinyl norbornene, dicyclopentadiene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, and 3-chloromethylstyrene, or a mixture of at least two thereof.

9. The olefin-based polymer according to claim 1, wherein the olefin-based polymer is a copolymer of ethylene and 1-octene.

10. The olefin-based polymer according to claim 1, wherein the olefin-based polymer has an elution termination temperature of 60° C. or less.

11. The olefin-based polymer according to claim 1, wherein the soluble fraction (SF) at −20° C. in cross-fractionation chromatography (CFC) is 10 wt % or more.

12. The olefin-based polymer according to claim 1, wherein the olefin-based polymer has (4) a molecular weight distribution (MWD) in a range of 1.0 to 3.0, and (6) MI.sub.10/MI.sub.12.16>7.91(MI.sub.12.16).sup.−0.188.

13. The olefin-based polymer according to claim 1, wherein the olefin-based polymer is obtained by a method of preparing an olefin-based polymer including a step of polymerizing an olefin-based monomer in the presence of a catalyst composition for olefin polymerization including a transition metal compound represented by the following Formula 1 and a transition metal compound represented by the following Formula 2 in an equivalent ratio of 1:1 to 1:5: ##STR00009## in Formula 1, R.sub.1s are the same or different, and each independently represent hydrogen, an alkyl having 1 to 20 carbon atoms, an alkenyl having 2 to 20 carbon atoms, an aryl, a silyl, an alkylaryl, an arylalkyl or a metalloid radical of a Group 4 metal substituted with a hydrocarbyl, and the two R.sub.1s are optionally connected together by an alkylidene radical including an alkyl radical having 1 to 20 carbon atoms or an aryl radical having 6 to 20 carbon atoms to form a ring; R.sub.2s are the same or different, and each independently represent hydrogen; a halogen; an alkyl having 1 to 20 carbon atoms; an aryl; an alkoxy; an aryloxy; or amido radical, and two or more of the R.sub.2s are optionally connected to each other to form an aliphatic ring or an aromatic ring; R.sub.3s are the same or different, and each independently represent hydrogen; a halogen; an alkyl having 1 to 20 carbon atoms; or an aliphatic or aromatic ring which contains nitrogen and is substituted with an aryl radical or unsubstituted, and when the number of substituents is plural, the substituents are optionally connected to each other to form an aliphatic or aromatic ring; M.sub.1 is a Group 4 transition metal; and Q.sub.1 and Q.sub.2 each independently represent a halogen; an alkyl having 1 to 20 carbon atoms; an alkenyl; an aryl; an alkylaryl; an arylalkyl; an alkylamido having 1 to 20 carbon atoms; an arylamido; or an alkylidene radical having 1 to 20 carbon atoms; ##STR00010## in Formula 2, R.sub.4s are the same or different, and each independently represent hydrogen, an alkyl having 1 to 20 carbon atoms, an alkenyl having 2 to 20 carbon atoms, an aryl, a silyl, an alkylaryl, an arylalkyl or a metalloid radical of a Group 4 metal substituted with a hydrocarbyl, and the two R.sub.4 are optionally connected together by an alkylidene radical including an alkyl having 1 to 20 carbon atoms or an aryl radical having 6 to 20 carbon atoms to form a ring; R.sub.5s are the same or different, and each independently represent hydrogen; a halogen; an alkyl having 1 to 20 carbon atoms; an aryl; an alkoxy; or an aryloxy; an amido radical, and two or more of the R.sub.5s are optionally connected to each other to form an aliphatic ring or an aromatic ring; R.sub.6s are the same or different, and each independently represent hydrogen; a halogen; an alkyl having 1 to 20 carbon atoms; or an aliphatic or aromatic ring which contains nitrogen and is substituted with an aryl radical or unsubstituted, and when the number of substituents is plural, the substituents are optionally connected to each other to form an aliphatic or aromatic ring; M.sub.2 is a Group 4 transition metal; and Q.sub.3 and Q.sub.4 each independently represent a halogen; an alkyl having 1 to 20 carbon atoms; an alkenyl; an aryl; an alkylaryl; an arylalkyl; an alkylamido having 1 to 20 carbon atoms; an arylamido; or an alkylidene radical having 1 to 20 carbon atoms.

14. The olefin-based polymer according to claim 13, wherein the olefin-based polymer is prepared by a continuous solution polymerization reaction using a continuous stirred tank reactor in the presence of the catalyst composition for olefin polymerization.

15. The olefin-based polymer according to claim 7, wherein the alpha-olefin is in an amount of 90% wt % or less.

16. The olefin-based polymer according to claim 13, wherein the transition metal compound represented by Formula 1 is one or more selected from the group consisting of the following Formulae 1-1 and 1-2, and the transition metal compound represented by Formula 2 has the following Formula 2-1: ##STR00011##

Description

BEST MODE FOR CARRYING OUT THE INVENTION

Examples

(1) Hereinafter, the present invention will be explained in particular with reference to the following examples. However, the following examples are illustrated to assist the understanding of the present invention, and the scope of the present invention is not limited thereto.

Preparation Example 1

Preparation of Transition Metal Compound 1

(2) (1) Preparation of 8-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl)-1,2,3,4-tetrahydroquinoline

(3) ##STR00006##

(4) (i) Preparation of Lithium Carbamate

(5) 1,2,3,4-tetrahydroquinoline (13.08 g, 98.24 mmol) and diethyl ether (150 mL) were put into a Schlenk flask. The above-described Schlenk flask was immersed in a low-temperature bath at −78° C. formed of dry ice and acetone, and stirred for 30 minutes. Subsequently, n-BuLi (39.3 mL, 2.5 M, 98.24 mmol) was added thereto via syringe under a nitrogen atmosphere, and thereby pale yellow slurry was formed. Then, after the flask was stirred for 2 hours, the temperature of the flask was raised to room temperature while removing the produced butane gas. The flask was immersed again in a low-temperature bath at −78° C. to lower a temperature, and then CO.sub.2 gas was introduced thereto. As carbon dioxide gas was introduced, the slurry disappeared and the solution became clear. The flask was connected to a bubbler to remove the carbon dioxide gas, and the temperature was raised to room temperature. Thereafter, an excess amount of CO.sub.2 gas and a solvent were removed under vacuum. The flask was transferred to a dry box, and pentane was added thereto, followed by vigorous stirring and filtration to obtain lithium carbamate which is a white solid compound. The white solid compound is coordinated with diethyl ether. The yield is 100%.

(6) .sup.1H NMR(C.sub.6D6, C.sub.5D.sub.5N): δ 1.90 (t, J=7.2 Hz, 6H, ether), 1.50 (br s, 2H, quin-CH.sub.2), 2.34 (br s, 2H, quin-CH.sub.2), 3.25 (q, J=7.2 Hz, 4H, ether), 3.87 (br s, 2H, quin-CH.sub.2), 6.76 (br d, J=5.6 Hz, 1H, quin-CH) ppm

(7) .sup.13C NMR(C.sub.6D6): δ 24.24, 28.54, 45.37, 65.95, 121.17, 125.34, 125.57, 142.04, 163.09(C═O) ppm

(8) (ii) Preparation of 8-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl)-1,2,3,4-tetrahydroquinoline

(9) The lithium carbamate compound prepared in Step (i) (8.47 g, 42.60 mmol) was put into a Schlenk flask. Then, tetrahydrofuran (4.6 g, 63.9 mmol) and 45 mL of diethyl ether were added in sequence. The Schlenk flask was immersed in a low-temperature bath at −20° C. including acetone and a small amount of dry ice and stirred for 30 minutes, and then t-BuLi (25.1 mL, 1.7 M, 42.60 mmol) was added. At this time, the color of the reaction mixture turned red. The mixture was stirred for 6 hours while a temperature was maintained at −20° C. A CelC.sub.3.2LiCl solution (129 mL, 0.33 M, 42.60 mmol) dissolved in tetrahydrofuran and tetramethylcyclopentinone (5.89 g, 42.60 mmol) were mixed in a syringe, and then introduced into the flask under a nitrogen atmosphere. The temperature of the flask was slowly raised to room temperature. After 1 hour, a thermostat was removed and the temperature was maintained at room temperature. Subsequently, water (15 mL) was added to the flask, and ethyl acetate was added thereto, followed by filtration to obtain a filtrate. The filtrate was transferred to a separatory funnel, followed by the addition of hydrochloric acid (2 N and 80 mL) and shaking for 12 minutes. A saturated aqueous solution of sodium hydrogencarbonate (160 mL) was added for neutralization, and then an organic layer was extracted. Anhydrous magnesium sulfate was added to the organic layer to remove moisture, followed by filtration, and the filtrate was taken to remove the solvent. The obtained filtrate was purified by column chromatography using hexane and ethyl acetate (v/v, 10:1) to obtain yellow oil. The yield was 40%.

(10) .sup.1H NMR(C.sub.6D.sub.6): δ 1.00 (br d, 3H, Cp-CH.sub.3), 1.63-1.73 (m, 2H, quin-CH.sub.2), 1.80 (s, 3H, Cp-CH.sub.3), 1.81 (s, 3H, Cp-CH.sub.3), 1.85 (s, 3H, Cp-CH.sub.3), 2.64 (t, J=6.0 Hz, 2H, quin-CH.sub.2), 2.84-2.90 (br, 2H, quin-CH.sub.2), 3.06 (br s, 1H, Cp-H), 3.76 (br s, 1H, N-H), 6.77 (t, J=7.2 Hz, 1H, quin-CH), 6.92 (d, J=2.4 Hz, 1H, quin-CH), 6.94 (d, J=2.4 Hz, 1H, quin-CH) ppm

(11) (2) Preparation of [(1,2,3,4-tetrahydroquinolin-8-yl)tetramethylcyclopentadienyl-η.sup.5, κ-N]titanium dimethyl)

(12) ##STR00007##

(13) (i) Preparation of [(1,2,3,4-tetrahydroquinolin-8-yl) tetramethylcyclopentadienyl-η.sup.5, κ-N] dilithium compound

(14) After 8-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl)-1,2,3,4-tetrahydroquinoline (8.07 g, 32.0 mmol) prepared by

(15) Step (1) and 140 mL of diethyl ether were put in a round flask in a dry box, a temperature was lowered to −30° C. and n-BuLi (17.7 g, 2.5 M, 64.0 mmol) was slowly added while stirring. The reaction was allowed to proceed for 6 hours while the temperature was raised to room temperature.

(16) Thereafter, the solid was obtained by filtration while washing with diethyl ether several times. A vacuum was applied to remove the remaining solvent to obtain a di-lithium compound (9.83 g) which is a yellow solid. The yield was 95%.

(17) .sup.1H NMR(C.sub.6D6, C.sub.5D.sub.5N): δ 2.38 (br s, 2H, quin-CH.sub.2), 2.53 (br s, 12H, Cp-CH.sub.3), 3.48 (br s, 2H, quin-CH.sub.2), 4.19 (br s, 2H, quin-CH.sub.2), 6.77 (t, J=6.8 Hz, 2H, quin-CH), 7.28 (br s, 1H, quin-CH), 7.75 (brs, 1H, quin-CH) ppm

(18) (ii) Preparation of (1,2,3,4-tetrahydroquinolin-8-yl) tetramethylcyclopentadienyl-η.sup.5, κ-N]titanium dimethyl

(19) In a dry box, TiCl.sub.4.DME (4.41 g, 15.76 mmol) and diethyl ether (150 mL) were put into a round flask and MeLi (21.7 mL, 31.52 mmol and 1.4 M) was slowly added while stirring at −30° C. After stirring for 15 minutes, [(1,2,3,4-tetrahydroquinolin-8-yl)tetramethylcyclopentadienyl-η.sup.5, κ-N] dilithium compound (5.30 g, 15.76 mmol) prepared in Step (i) was put into the flask. The mixture was stirred for 3 hours while the temperature was raised to room temperature. After completion of the reaction, the solvent was removed by vacuum, the mixture was dissolved in pentane and filtered to obtain the filtrate. A vacuum was applied to remove pentane to obtain a dark brown compound (3.70 g). The yield was 71.3%.

(20) .sup.1H NMR(C.sub.6D.sub.6): δ 0.59 (s, 6H, Ti-CH.sub.3), 1.66 (s, 6H, Cp-CH.sub.3), 1.69 (br t, J=6.4 Hz, 2H, quin-CH.sub.2), 2.05 (s, 6H, Cp-CH.sub.3), 2.47 (t, J=6.0 Hz, 2H, quin-CH.sub.2), 4.53 (m, 2H, quin-CH.sub.2), 6.84 (t, J=7.2 Hz, 1H, quin-CH), 6.93 (d, J=7.6 Hz, quin-CH), 7.01 (d, J=6.8 Hz, quin-CH) ppm

(21) .sup.13C NMR(C.sub.6D.sub.6): δ 12.12, 23.08, 27.30, 48.84, 51.01, 119.70, 119.96, 120.95, 126.99, 128.73, 131.67, 136.21 ppm

Preparation Example 2

Preparation of Transition Metal Compound 2

(22) (1) Preparation of 2-methyl-7-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl) indoline

(23) 2-methyl-7-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl) indoline was prepared in the same manner as in (1) of Preparation Example 1 except that 2-methylindoline was used instead of 1,2,3,4-tetrahydroquinoline in (1) (i) of Preparation Example 1. The yield was 19%.

(24) .sup.1H NMR(C.sub.6D.sub.6): δ 6.97(d, J=7.2 Hz, 1H, CH), 5 6.78(d, J=8 Hz, 1H, CH), 5 6.67(t, J=7.4 Hz, 1H, CH), δ 3.94(m, 1H, quinoline-CH), δ 3.51(br s, 1H, NH), δ 3.24-3.08(m, 2H, quinoline-CH.sub.2, Cp-CH), δ 2.65(m, 1H, quinoline-CH.sub.2), δ 1.89(s, 3H, Cp-CH.sub.3), δ 1.84(s, 3H, Cp-CH.sub.3), δ 1.82(s, 3H, Cp-CH.sub.3), δ 1.13(d, J=6 Hz, 3H, quinoline-CH.sub.3), δ 0.93(3H, Cp-CH.sub.3) ppm.

(25) (2) Preparation of [(2-methylindolin-7-yl)tetramethylcyclopentadienyl-eta5,kappa-N]titanium dimethyl)

(26) ##STR00008##

(27) (i) A di-lithium salt compound (4 g) in which 0.58 equivalent of diethyl ether was coordinated was obtained (1.37 g, 50%) in the same manner as in (2) (i) of Preparation Example 1 except that 2-methyl-7-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl)-indoline cyclopentadienyl)-indoline (2.25 g, 8.88 mmol) was used instead of 8-(2,3,4,5-tetramethyl-1,3-cyclopentadienyl)-1,2,3,4-tetrahydroquinoline.

(28) .sup.1H NMR(Pyridine-d8), δ 7.22(br s, 1H, CH), δ 7.18(d, J=6 Hz, 1H, CH), δ 6.32(t, 1H, CH), δ 4.61(brs, 1H, CH), 5 3.54(m, 1H, CH), δ 3.00(m, 1H, CH), δ 2.35-2.12(m,13H, CH, Cp-CH.sub.3), δ 1.39(d, indoline-CH.sub.3) ppm.

(29) (ii) A titanium compound was prepared in the same manner as in (2) (ii) of Preparation Example 1 using the di-lithium salt compound (1.37 g, 4.44 mmol) prepared in the above (i).

(30) .sup.1H NMR(C.sub.6D.sub.6), δ 7.01-6.96(m, 2H, CH), δ 6.82(t, J=7.4 Hz, 1H, CH), 5

(31) 4.96(m, 1H, CH), δ 2.88(m, 1H, CH), δ 2.40(m, 1H, CH), 5 2.02(s, 3H, Cp-CH.sub.3), δ 2.01(s, 3H, Cp-CH.sub.3), δ 1.70(s, 3H, Cp-CH.sub.3), δ 1.69(s, 3H, Cp-CH.sub.3), δ 1.65(d, J=6.4 Hz, 3H, indoline-CH.sub.3), δ 0.71(d, J=10 Hz, 6H, TiMe.sub.2-CH.sub.3) ppm.

Example 1

(32) A 1.5 L-continuous process reactor was filled with a hexane solvent (5 kg/h) and 1-octene (1.5 kg/h), and a temperature at the top of the reactor was preheated to 140.7° C. A triisobutyl aluminum compound (0.05 mmol/min), a mixture (0.5 μmol/min) of a transition metal compound obtained by mixing the transition metal compound 1 obtained in Preparation Example 1 and the transition metal compound 2 obtained in Preparation Example 2 in a molar ratio of 1:3, and a dimethylanilinium tetrakis(pentafluorophenyl) borate cocatalyst (1.5 μmol/min) were simultaneously introduced into the reactor. Subsequently, ethylene (0.87 kg/h) was then fed into the reactor, and the copolymerization reaction was continued at 140.7° C. for 30 minutes or more in a continuous process at a pressure of 89 bar to obtain a copolymer. After drying for more than 12 hours in a vacuum oven, the physical properties were measured.

Examples 2 to 6

(33) The copolymerization reaction was carried out using the two transition metal catalysts as in Example 1. The ratio of the two transition metals, the ratio of the catalyst to the cocatalyst, the reaction temperature and the amount of the comonomer were changed as shown in the following Table 1. The reaction proceeded to obtain a copolymer.

Comparative Example 1

(34) Solumer851L manufactured by SK Global Chemical Co., LTD. was purchased and used.

Comparative Example 2

(35) EG8842 manufactured by the Dow Chemical Company was purchased and used.

Comparative Example 3

(36) The copolymerization reaction was carried out by using the same method as in Example 1 to obtain a copolymer except that only the transition metal compound 1 was used as a catalyst.

Comparative Example 4

(37) The copolymerization reaction was carried out in the same manner as in Example 1 to obtain a copolymer except that only the transition metal compound 2 was used as the catalyst.

Comparative Example 5

(38) The copolymerization reaction was carried out using the two transition metal catalysts as in Example 1. The ratio of the two transition metals, the ratio of the catalyst to the cocatalyst, the reaction temperature and the amount of the comonomer were changed as shown in the following Table 1, and the reaction proceeded to obtain a copolymer.

(39) TABLE-US-00001 TABLE 1 Catalyst ratio (Transition metal Reaction Catalyst compound Cocatalyst TiBAl Ethylene 1-octene temperature (μmol/min) 1:2) (μmol/min) (mmol/min) (kg/h) (kg/h) (° C.) Example 1 0.5 1:3 1.5 0.05 0.87 5 140.7 Example 2 0.55 1:3 1.65 0.6 0.87 5 145.2 Example 3 0.55 1:2 1.65 0.5 0.87 5 144.5 Example 4 0.5 1:3 1.5 0.04 0.87 5 140.7 Example 5 0.28 1:3 1.65 0.5 0.87 5 150.6 Example 6 0.42 1:1 1.2 0.5 0.87 3 148.1 Comparative 0.5 — 1.5 0.05 0.87 5 140.7 Example 1 Comparative 0.55 — 1.65 0.6 0.87 5 145.2 Example 2 Comparative 0.2 — 0.35 0.04 0.87 5 139 Example 3 Comparative 0.38 — 1.14 0.05 0.87 5 135.7 Example 4 Comparative 0.27 1:8 0.81 0.04 0.87 1.3 141.5 Example 5

Experimental Example 1

(40) The physical properties of the copolymers of Examples to 6 and Comparative Examples 1 to 5 were evaluated according to the following methods, and the results are shown in the following Table 2.

(41) 1) Density of Polymer

(42) Measurement was performed in accordance with ASTM D-792.

(43) 2) Melt Index (MI) of Polymer

(44) Measurement was performed in accordance with ASTM D-1238 [condition E, MI.sub.10 (190° C. and a load of 10 kg), MI.sub.2.16 (190° C. and a load of 2.16 kg)].

(45) 3) Weight Average Molecular Weight (Mw, g/mol) and Molecular Weight Distribution (MWD)

(46) The number-average molecular weight (Mn) and the weight-average molecular weight (Mw) each were measured by gel permeation chromatography (GPC), and the molecular weight distribution was calculated by dividing the weight average molecular weight by the number average molecular weight.

(47) Column: PL Olexis

(48) Solvent: Trichlorobenzene (TCB)

(49) Flow rate: 1.0 ml/min

(50) Concentration of specimen: 1.0 mg/ml

(51) Injection amount: 200 μl

(52) Column temperature: 160° C.

(53) Detector: Agilent High Temperature RI detector

(54) Standard: Polystyrene (Calibration using cubic function)

(55) 4) Melting Point (Tm) of Polymer

(56) The melting point was obtained using the differential scanning calorimeter (DSC) 6000 manufactured by PerkinElmer. That is, after the temperature was increased to 200° C., the temperature was maintained at that temperature for 1 minute, then decreased to −100° C., and the temperature was increased again to obtain the top of the DSC curve as the melting point. At this time, the rate of temperature rise and fall is 10° C./min, and the melting point is obtained during the second temperature rise.

(57) 5) Soluble Fraction, Weight Average Molecular Weight (Mw) of Soluble Fraction and Elution Termination Temperature

(58) The measurement equipment was a CFC of Polymer Char. First, a solution of the copolymer was fully dissolved in an oven at 130° C. for 60 minutes in a CFC analyzer using o-dichlorobenzene as a solvent, poured into a TREF column adjusted to 135° C., and then cooled to 95° C. and stabilized for 45 minutes. Subsequently, the temperature of the TREF column was lowered to −20° C. at a rate of 0.5° C./min, and then maintained at −20° C. for 10 minutes. Thereafter, the elution amount (mass %) was measured using an infrared spectrophotometer. Subsequently, the operation of raising the temperature of the TREF column to a predetermined temperature at a rate of 20° C./min and maintaining a temperature reached for a predetermined time (i.e., about 27 minutes) was repeated until the temperature of the TREF column reached 130° C., and the amount of eluted fraction (mass %) was measured during each temperature range. The fraction eluted at each temperature was sent to a GPC column, and the molecular weight Mw was measured in the same manner as in the GPC measurement, except that o-dichlorobenzene was used as a solvent.

(59) The content of the ultra-low crystalline region means the content of the fraction eluted at −20° C. or less, and the molecular weight Mw was measured using a GPC column of CFC.

(60) The elution termination temperature was defined as the final temperature at which no more fractions were eluted in the detector.

(61) TABLE-US-00002 TABLE 2 Elution SF termination Density MI.sub.2.16 Tm (CFC) temperature Mw of (g/mL) (g/10 min) (° C.) Mw MWD (wt %) (° C.) SF Example 1 0.856 1.07 32.5 131K 2.29 27.5 31 104827 Example 2 0.859 0.97 38.7 128K 2.08 16.8 34 82474 (MI.sub.10 7.86) Example 3 0.857 1.10 35.2 122K 2.08 25.3 31 60064 Example 4 0.855 1.74 28.9 112K 2.15 40.7 28 161537 Example 5 0.861 1.02 42.2 126K 2.16 10.7 40 102736 (MI.sub.10 10.4) Example 6 0.860 1.20 41.8 119K 2.22 12.6 38 75326 Comparative 0.859 1.06 44.4 130K 2.36 14.6 34 40675 Example 1 Comparative 0.859 0.95 43.1 132K 2.02 5.3 52 135552 Example 2 Comparative 0.858 1.44 36.3 120K 2.01 5.8 37 191817 Example 3 Comparative 0.861 1.19 38.8 124K 2.03 1.4 40 50581 Example 4 Comparative 0.861 0.59 44.5 154K 2.32 5.5 76.0 43971 Example 5

(62) In Table 2, the elution termination temperature is defined as the final temperature at which the fraction is no longer eluted in the detector, and a low elution termination temperature is a general feature of low-density olefin-based polymers which are distinguished from polymers having high density or high crystallinity such as LDPE, HDPE, LLDPF, etc.

(63) In Table 2, the higher the SF (>8%), the higher the impact strength at compounding, but it is very difficult to increase the SF content at the same density to a certain level or more. Even if the SF content is increased as in

(64) Comparative Example 1, the molecular weight of the fraction is lowered, which is detrimental to the anti-blocking properties. The copolymers of the Examples have excellent impact strength and anti-blocking properties by maintaining the molecular weight of the fraction high while maintaining the SF content high.

Experimental Example 2

(65) 50 g of the pellets of each of the copolymers prepared in Example 2 and Comparative Examples 1 and 2 were taken and put into an 8 cm×10 cm zipper bag. The zipper bag was pierced with a needle to remove air and squeezed. The zipper bag was placed in the center part away from the bottom of the chamber, and the load was applied with two 2 kg weights above. The chamber temperature program was run and allowed to stand at 35° C. for 7 hours, at −5° C. for 5 hours and at 0° C. for 5 hours, and maintained at 0° C. Thereafter, the degree of blocking was confirmed.

(66) Further, 50 g of the pellets of each of the copolymers prepared in Example 2 and Comparative Example 1 were taken, treated with 700 ppm of PDMS (polydimethylsiloxane, XIAMETER® MEM-0039 emulsion, Dow-Corning/PDMS 35 wt %) and 450 ppm of Ca-st (calcium stearate, SC-130, SongWon Industry Co.,Ltd), which are commonly used surface treatment agents, and put into an 8 cm×10 cm zipper bag. The zipper bag was pierced with a needle to remove air and squeezed.

(67) The zipper bag was placed in the center part away from the bottom of the chamber, and the load was applied with two 2 kg weights above. The chamber temperature program was run and allowed to stand at 35° C. for 7 hours, at −5° C. for 5 hours and at 0° C. for 5 hours, and maintained at 0° C. Thereafter, the degree of blocking was confirmed.

(68) Further, 50 g of the pellets of each of the copolymers prepared in Example 2 and Comparative Example 2 were taken, treated with 4,000 ppm of Talc (KCM6300) which is a commonly used surface treatment agent, and put into an 8 cm×10 cm zipper bag. The zipper bag was pierced with a needle to remove air and squeezed.

(69) The zipper bag was placed in the center part away from the bottom of the chamber, and the load was applied with two 2 kg weights above. The chamber temperature program was run and allowed to stand at 35° C. for 7 hours, at −5° C. for 5 hours and at 0° C. for 5 hours, and maintained at 0° C. Thereafter, the degree of blocking was confirmed.

(70) The evaluation criteria are shown in the following Table 3, and the experimental results are shown in the following Table 4.

(71) TABLE-US-00003 TABLE 3 Grade Status 0 Spilled when the zipper bag was open and turned 1 Released during removal of zipper bag 2 Lump from which the zipper bag was removed disintegrates within 20 seconds 3 Disintegrates when pressed by hand 4 Disintegrates when pressed with a strong force 5 Not disintegrated when pressed by hand

(72) TABLE-US-00004 TABLE 4 Type of surface treatment agent Type of (amount used, ppm) Blocking copolymer PDMS Ca-St Talc evaluation Example 2 — — — 4 700 450 1 4,000 1 Comparative — — — 5 Example 1 700 450 — 3 Comparative —  4000 5 Example 2

(73) Referring to Table 4, it was confirmed that when the copolymers of Example 2 and Comparative Example 1 were not treated with a separate surface treatment agent, the copolymer of Example 2 had better anti-blocking properties. Further, when the PDMS and the Ca-st, which are surface treatment agents commonly used as anti-blocking agents, were used for the copolymers of Example 2 and Comparative Example 1, the copolymer of Example 2 was also superior in anti-blocking properties. This was also the case when talc was used as a surface treating agent.

(74) Thus, it was confirmed that the copolymer of Example 2 exhibited excellent blocking resistance as compared with the copolymer of Comparative Example 1, under both of the condition of not using the surface treatment agent and the condition of using the same surface treatment agent.