Polyolefin
The present invention relates to polyolefin. More specifically, the present invention relates to polyolefin having excellent dart drop impact strength, and exhibiting improved transparency, and such polyolefin has a density of 0.915 g/cm 3 to 0.930 g/cm 3 measured according to ASTM D1505; and has an ethylene sequence inhomogeneity (I) calculated by the following Equation 1 of 1.25 to 1.40, when analyzed by SSA (Successive Self-nucleation and Annealing): Inhomogeneity ( I )= L w /L n [Equation 1] in the Equation 1, L w is weighted average (unit: nm) of ESL (Ethylene sequence length), and L n is arithmetic mean (unit: nm) of ESL (Ethylene sequence length).
1. A polyolefin having a density of 0.915 g/cm 3 to 0.920 g/cm 3 measured according to ASTM D1505; and
an ethylene sequence inhomogeneity (I) calculated by Equation 1 of 1.26 to 1.29, when analyzed by a Successive Self-nucleation and Annealing (SSA) thermogram:
Inhomogeneity ( I )= L w /L n [Equation 1]
in Equation 1,
the L n is calculated by Equation 2, and the L w is calculated by Equation 3:
L
n
=
S
1
L
1
2
+
S
2
L
2
2
+
S
3
L
3
2
+
…
+
S
i
L
i
2
S
1
+
S
2
+
S
3
+
…
+
S
i
=
∑
f
i
L
i
[
Equation
2
]
L
w
=
S
1
L
1
2
+
S
2
L
2
2
+
S
3
L
3
2
+
…
+
S
i
L
i
2
S
1
L
1
+
S
2
L
2
+
S
3
L
3
+
…
+
S
i
L
i
=
∑
f
i
L
i
2
∑
f
i
L
i
[
Equation
3
]
in Equations 2 and 3,
S i is an area of a melting peak measured by the SSA thermogram, and
L i is an average ethylene sequence length corresponding to the melting peak in the SSA thermogram,
wherein the SSA thermogram is obtained by heating the polyolefin to a first heating temperature of 120 to 124° C. using differential scanning calorimetry, maintaining for 15 to 30 minutes for annealing, and then cooling to 28 to 32° C. for quenching; and while gradually decreasing a subsequent heating temperature by stages with (n+1)th heating temperature being 3 to 7° C. lower than nth heating temperature, repeating the heating, the annealing and the quenching until a final heating temperature becomes 50 to 54° C., and
which has a haze measured according to ISO 13468, of 11% or less, by a polyolefin film having a thickness of 55 to 65 μm, prepared from the polyolefin using a single screw extruder at an extrusion temperature of 130˜170° C., a die gap of 2.0 mm, and a blown-up ratio of 2.3, and
a dart drop impact strength measured according to ASTM D 1709 [Method A], of 1210 g or more, by a polyolefin film having a thickness of 55 to 65 μm, prepared from the polyolefin using a single screw extruder at an extrusion temperature of 130˜170° C., a die gap of 2.0 mm, and a blown-up ratio of 2.3.
2. The polyolefin according to claim 1 , which has a melt index (MI 2.16 ) measured under load of 2.16 kg at a temperature of 190° C. according to ASTM D1238 of 0.5 to 1.5 g/10 min.
3. The polyolefin according to claim 1 , wherein the polyolefin is copolymer of ethylene and alpha olefin.
4. The polyolefin according to claim 3 , wherein the alpha olefin includes one or more 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-methyl styrene, divinylbenzene, or 3-chloromethyl styrene.
5. The polyolefin according to claim 1 , wherein the polyolefin is prepared by polymerizing olefin monomers, in the presence of a hybrid supported metallocene catalyst comprising a first metallocene compound selected from a compound represented by Chemical Formula 1; a second metallocene compound selected from a compound represented by Chemical Formula 2; and a carrier supporting the first and second metallocene compounds:
in Chemical Formula 1,
Q 1 and Q 2 are identical to or different from each other, and each independently, halogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkoxyalkyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, or a C7-C20 arylalkyl group;
T 1 is carbon, silicon or germanium;
M 1 is a Group 4 transition metal;
X 1 and X 2 are identical to or different from each other, and each independently, halogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C6-C20 aryl group, a nitro group, an amido group, a C1-C20 alkylsilyl group, a C1-C20 alkoxy group, or a C1-C20 sulfonate group; and
R 1 to R 14 are identical to or different from each other, and each independently, hydrogen, halogen, a C1-C20 alkyl group, a C1-C20 haloalkyl group, a C2-C20 alkenyl group, a C1-C20 alkylsilyl group, a C1-C20 silylalkyl group, a C1-C20 alkoxysilyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C7-C20 alkylaryl group, or a C7-C20 arylalkyl group, or two or more neighboring groups of R 1 to R 14 are connected with each other to form a substituted or unsubstituted aliphatic or aromatic ring;
in Chemical Formula 2,
Q 3 and Q 4 are identical to or different from each other, and each independently, halogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkoxyalkyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, or a C7-C20 arylalkyl group;
T2 is carbon, silicon or germanium;
M2 is a Group 4 transition metal;
X 3 and X 4 are identical to or different from each other, and each independently, halogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C6-C20 aryl group, a nitro group, an amido group, a C1-C20 alkylsilyl group, a C1-C20 alkoxy group, or a C1-C20 sulfonate group; and
R 15 to R 19 , R 21 to R 23 , and R 25 to R 28 are identical to or different from each other, and each independently, hydrogen, halogen, a C1-C20 alkyl group, a C1-C20 haloalkyl group, a C2-C20 alkenyl group, a C2-C20 alkoxyalkyl group, a C1-C20 alkylsilyl group, a C1-C20 silylalkyl group, a C1-C20 alkoxysilyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C7-C20 alkylaryl group, or a C7-C20 arylalkyl group, or two or more neighboring groups of R 15 to R 19 , R 21 to R 23 , and R 25 to R 28 are connected with each other to form a substituted or unsubstituted aliphatic or aromatic ring, and R 20 and R 24 are identical to or different from each other, and each independently a C1 to C20 alkyl group.
6. The polyolefin according to claim 5 , wherein the compound represented by Chemical Formula 1 is any one represented by the following Structural Formulas:
7. The polyolefin according to claim 5 , wherein the compound represented by Chemical Formula 2 is any one represented by the following Structural Formulas:
8. The polyolefin according to claim 5 , wherein a mole ratio of the first and second metallocene compounds is 1:1 to 10:1.
9. The polyolefin according to claim 5 , wherein in the Chemical Formula 1, R 11 to R 14 are each independently a C1 to C20 alkyl group, R 1 is hydrogen or a C1 to C20 alkyl group, R 2 to R 10 are each hydrogen, Q 1 and Q 2 are each independently a C1 to C20 alkyl group or a C6 to C20 aryl group, X 1 and X 2 are each independently halogen, and M 1 is Ti, Zr or Hf.
10. The polyolefin according to claim 5 , wherein in the Chemical Formula 2, R 25 and R 28 are each independently hydrogen, a C1 to C20 alkyl group, or a C2 to C20 alkoxyalkyl group, Q 3 and Q 4 are independently a C1 to C20 alkyl group or a C2 to C20 alkoxyalkyl group, X 3 and X 4 are each independently halogen, and M2 is Ti, Zr or Hf.