阅读说明：本技术 聚烯烃 (Polyolefins ) 是由 李真营 李承珉 李政圭 李效埈 金世英 朴成镐 林涩琪 金祏焕 洪大植 于 2019-12-20 设计创作，主要内容包括：本发明涉及聚烯烃。更特别地,本发明涉及具有优异的落镖冲击强度并且显示出改善的透明性的聚烯烃。(The present invention relates to polyolefins. More particularly, the present invention relates to a polyolefin having excellent dart impact strength and exhibiting improved transparency.)

1. A polyolefin having a density of 0.915g/cm³To 0.930g/cm³(ii) a And

the ethylene sequence heterogeneity (I) calculated from the following equation 1 is 1.25 to 1.40 when analyzed by SSA (sequential self nucleation and annealing):

[ equation 1]

Heterogeneity of (I) ═ L_w/L_n

In the case of the equation 1, the,

L_wis the weighted average (unit: nm) of the ESL (ethylene sequence length), and L_nIs the arithmetic mean (unit: nm) of ESL (ethylene sequence length).

2. The polyolefin of claim 1, wherein L is_nCalculated by the following equation 2, and L_wCalculated from equation 3 below:

[ equation 2]

[ equation 3]

In the case of the equations 2 and 3,

S_iis the area of each melting peak measured in the SSA thermogram, an

L_iIs the ASL (average ethylene sequence length) corresponding to each melting peak in the SSA thermogram.

3. Polyolefin according to claim 1, wherein SSA is carried out by: the polyolefin is heated to a first heating temperature of 120 to 124 ℃ using differential scanning calorimetry, held for 15 to 30 minutes, then cooled to 28 to 32 ℃, and while the (n +1) th heating temperature is lowered by 3 to 7 ℃ below the nth heating temperature, the heating-annealing-quenching is repeated until the final heating temperature becomes 50 to 54 ℃.

4. The polyolefin of claim 1, wherein the Melt Index (MI) measured at a temperature of 190 ℃ under a load of 2.16kg according to ASTM D1238_2.16) Is 0.5 to 1.5g/10 min.

5. Polyolefin according to claim 1 wherein the polyolefin film prepared using a film maker (BUR 2.3, film thickness 55 to 65 μ ι η) has a haze of 11% or less measured according to ISO 13468.

6. The polyolefin of claim 1, wherein the dart drop impact strength of a polyolefin film prepared using a film maker (BUR 2.3, film thickness 55 to 65 μ ι η) measured according to ASTM D1709[ method a ] is 850g or more.

7. The polyolefin of claim 1, wherein the polyolefin is a copolymer of ethylene and an alpha-olefin.

8. The polyolefin of claim 7, wherein the alpha-olefin comprises 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, 1-eicosene, norbornene, norbornadiene, ethylidene norbornene, phenylnorbornene, vinyl norbornene, dicyclopentadiene, 1, 4-butadiene, 1, 5-pentadiene, 1, 6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, and 3-chloromethylstyrene.

9. The polyolefin of claim 1, wherein the polyolefin is prepared by polymerizing olefin monomers in the presence of a hybrid supported metallocene catalyst comprising one or more first metallocene compounds selected from the group consisting of compounds represented by the following chemical formula 1; one or more second metallocene compounds selected from the group consisting of compounds represented by the following chemical formula 2; and a support supporting the first and second metallocene compounds:

[ chemical formula 1]

In the chemical formula 1, the first and second,

Q₁and Q₂Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkoxyalkyl, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl;

T₁is carbon, silicon or germanium;

M₁is a group 4 transition metal;

X₁and X₂Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, nitro, amino, C1-C20 alkylsilyl, C1-C20 alkoxy, or C1-C20 sulfonate group;

R₁to R₁₄Identical or different from one another and are each independently hydrogen, halogen, C1-C20 alkyl, C1-C20 haloalkyl, C2-C20 alkenyl, C1-C20 alkylsilyl, C1-C20 silylalkyl, C1-C20 alkoxysilyl, C1-C20 alkoxy, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl, or R₁To R₁₄Two or more adjacent groups of (a) are linked to each other to form a substituted or unsubstituted aliphatic or aromatic ring;

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

Q₃and Q₄Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkoxyalkyl, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl;

T₂is carbon, silicon or germanium;

M₂is a group 4 transition metal;

X₃and X₄Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, nitro, amino, C1-C20 alkylsilyl, C1-C20 alkoxy, or C1-C20 sulfonate group;

R₁₅to R₂₈Are identical to or different from one another and are each independently hydrogen, halogen, C1-C20 alkyl, C1-C20 haloalkyl, C2-C20 alkenyl, C2-C20 alkoxyalkyl, C1-C20 alkylsilyl, C1-C20 silylalkyl, C1-C20 alkoxysilyl, C1-C20 alkoxy, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl, with the proviso that R1-C20 alkoxy is hydrogen, halogen, C1-C20 alkyl, C3626-C20 haloalkyl, C1-C7 arylalkyl₂₀And R₂₄Are identical or different from one another and are each independently C1 to C20 alkyl, or R₁₅To R₂₈Two or more adjacent groups in (a) are linked to each other to form a substituted or unsubstituted aliphatic or aromatic ring.

10. The polyolefin of claim 9, wherein the compound represented by chemical formula 1 is one of compounds represented by the following structural formulae:

11. the polyolefin of claim 9, wherein the compound represented by chemical formula 2 is one of compounds represented by the following structural formulae:

12. the polyolefin of claim 9, wherein the molar ratio of the first and second metallocene compounds is from 1:1 to 10: 1.

Technical Field

Cross Reference to Related Applications

This application claims the benefits of korean patent application No. 10-2018-.

The present invention relates to polyolefins. More particularly, the present invention relates to polyolefins having improved mechanical properties (such as excellent dart impact strength) and which can exhibit improved transparency when films are prepared.

Background

Linear Low Density Polyethylene (LLDPE) is produced by copolymerizing ethylene with α -olefins at low pressure using a polymerization catalyst, and it has a narrow molecular weight distribution and a short chain branch of a certain length, and has no long chain branch. Linear low density polyethylene films have high elongation and breaking strength, and excellent tear strength and dart impact strength, as well as general properties of polyethylene, and thus, are increasingly used in stretch films, overlaminate films, and the like, to which existing low density polyethylene or high density polyethylene cannot be applied.

However, linear low density polyethylene has poor blown film processability and low transparency compared to excellent mechanical properties. Blown films are films made by blowing air into molten plastic to expand, also known as expanded films (inflation film).

Meanwhile, as the density of the linear low density polyethylene decreases, the dart drop impact strength increases. However, if many comonomers are used to make low density polyethylene, fouling may often occur during slurry polymerization.

Meanwhile, processability can be improved by introducing LCB (long chain branching) in linear low density polyethylene, but as LCB increases, transparency and dart impact strength decrease.

Therefore, it is required to develop polyethylene having a low density and capable of realizing excellent mechanical properties (such as dart impact strength) and transparency.

Documents of the prior art

Patent document

(patent document 1) Korean patent application publication No. 2010-0102854

Disclosure of Invention

Technical problem

In order to solve the problems of the prior art, it is an object of the present invention to provide a polyolefin having a low density and improved mechanical properties (such as excellent dart impact strength) and which can exhibit improved transparency when a film is produced.

Technical scheme

To achieve this object, the present invention provides a polyolefin having a density of 0.915g/cm³To 0.930g/cm³(ii) a And

the ethylene sequence heterogeneity (I) calculated from the following equation 1 is 1.25 to 1.40 when analyzed by SSA (sequential self nucleation and annealing):

[ equation 1]

Heterogeneity of (I) ═ L_w/L_n

In the case of the equation 1, the,

L_wis a weighted average (unit: nm) of ESL (ethylene sequence length), and Ln is an arithmetic average (unit: nm) of ESL (ethylene sequence length).

Advantageous effects

According to the present invention, in the polymerization process of polyolefin using a metallocene catalyst, the length and distribution of ethylene sequences forming platelets can be properly controlled, thereby providing polyolefin having optimal ethylene sequence heterogeneity.

Therefore, a polyolefin having excellent transparency and high dart impact strength can be provided.

Drawings

Fig. 1 is a graph showing the relationship between the heterogeneity and the dart impact strength of polyolefins according to examples and comparative examples.

Fig. 2 shows a temperature profile of an SSA analysis according to an embodiment of the present invention.

Detailed Description

As used herein, the terms "first," "second," and the like are used to explain various structural elements, and they are used only to distinguish one structural element from other structural elements.

Also, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or the like, are intended to indicate the presence of stated features, integers, steps, structural elements, or combinations thereof, as practiced, and they are not intended to preclude the possibility of one or more other features, integers, steps, structural elements, or combinations thereof being present or added.

While the present invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that these are not intended to limit the invention to the particular disclosure, and that the invention includes all modifications, equivalents, and alternatives thereof without departing from the spirit and technical scope of the invention.

Hereinafter, the polyolefin according to the present invention will be explained in detail.

The polyolefin according to one embodiment of the present invention is characterized by a density of 0.915g/cm³To 0.930g/cm³(ii) a And ethylene sequence heterogeneity (I) calculated from the following equation 1 is 1.25 to 1.40 when analyzed by SSA (sequential self nucleation and annealing):

[ equation 1]

Heterogeneity of (I) ═ L_w/L_n

In the case of the equation 1, the,

L_wis a weighted average (unit: nm) of ESL (ethylene sequence length), and Ln is an arithmetic average (unit: nm) of ESL (ethylene sequence length).

Linear Low Density Polyethylene (LLDPE) is prepared by copolymerizing ethylene with alpha-olefins at low pressure using a polymerization catalyst, having a narrow molecular weight distribution and short chain branches of a certain length. Linear low density polyethylene films have high breaking strength and elongation, excellent tear strength and dart drop impact strength, and general properties of polyethylene, and thus are increasingly used in stretch films, overlaminate films, and the like, to which existing low density polyethylene or high density polyethylene cannot be applied.

Meanwhile, it is known that as the density of linear low density polyethylene decreases, the transparency and dart impact strength increase. However, if a large amount of comonomer is used to prepare low density polyethylene, fouling may frequently occur during slurry polymerization, and the amount of the antiblocking agent may increase due to stickiness when a film comprising the low density polyethylene is prepared. Also, the production process may be unstable, or the morphology of the produced polyethylene may be deteriorated, thereby reducing the bulk density.

Accordingly, the present invention provides a polyolefin having not only a low density but also an optimum ASL (average ethylene sequence length) ratio capable of increasing transparency and dart impact strength by appropriately controlling the length and distribution of ethylene sequences forming platelets.

In particular, the polyolefin according to one embodiment of the invention has 0.915g/cm³Above and 0.930g/cm³The following densities. That is, it may be a density of 0.930g/cm³The following low density polyolefins.

According to one embodiment of the invention, the polyolefin may be, for example, a copolymer of ethylene and an alpha-olefin. Wherein the alpha-olefin may include 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. The polyolefin may be a copolymer of ethylene and 1-butene, a copolymer of ethylene and 1-hexene, or a copolymer of ethylene and 1-octene.

More particularly, according to one embodiment, the polyolefin may have a density of 0.915g/cm³Above, or 0.916g/cm³Above, or 0.917g/cm³Above, or 0.918g/cm³Above, or 0.919g/cm³Above, and 0.930g/cm³Below, or 0.928g/cm³Below, or 0.925g/cm³Below, or 0.922g/cm³Below, or 0.921g/cm³Below, or 0.920g/cm³The following. Wherein density is a value measured according to ASTM D1505.

According to one embodiment of the present invention, the polyolefin is characterized in that the ethylene sequence heterogeneity (I) calculated by the following equation 1 is 1.25 to 1.40 when analyzed by SSA (sequential self nucleation and annealing).

[ equation 1]

Non-uniformity (I) ═ L_w/L_n

In the case of the equation 1, the,

L_wis the weighted average (unit: nm) of the ESL (ethylene sequence length), and L_nIs the arithmetic mean (unit: nm) of ESL (ethylene sequence length).

The polyolefins of the present invention are semi-crystalline polymers and may include crystalline portions and amorphous portions. Specifically, polymer chains comprising ethylene repeating units fold to form bundles, thereby forming crystalline blocks (or segments) in the form of platelets. The ethylene repeating units forming the plate-like crystals are ethylene sequences.

The present invention is based on the following findings: when the ethylene sequence heterogeneity (I) calculated from equation 1 is 1.25 to 1.40 by SSA (sequential self-nucleation and annealing) analysis, the polyolefin may have improved transparency and dart impact strength, compared to the existing polyolefin having the same density.

SSA (sequential self-nucleation and annealing) is a method in which quenching is performed at the end of each stage while the temperature is stepped down using a Differential Scanning Calorimeter (DSC), thereby retaining crystals crystallized at the corresponding temperature at each stage.

Specifically, if the polyolefin is heated to be completely melted, then cooled to a specific temperature (T) and gradually annealed, unstable platelets will still melt and only stable platelets will crystallize at the corresponding temperature (T). Wherein the stability to the respective temperature (T) depends on the thickness of the platelets, which depends on the structure of the chain. Therefore, by performing the heat treatment in stages, the thickness and the degree of distribution of the platelets according to the structure of the polymer chain can be quantitatively measured, and thus the distribution of each melting peak area can be measured.

According to one embodiment of the present invention, SSA may be performed by: the polyolefin is heated to a first heating temperature of 120 to 124 ℃ using DSC, held for 15 to 30 minutes, then cooled to 28 to 32 ℃, and while the (n +1) th heating temperature is made lower than the nth heating temperature by a stepwise decreasing heating temperature of 3 to 7 ℃, the heating-annealing-quenching is repeated until the final heating temperature becomes 50 to 54 ℃.

More specifically, SSA can be performed by the following steps i) to v):

i) the polyolefin was heated to 160 ℃ using DSC and then held for 30 minutes to remove all the thermal history before the measurement;

ii) the temperature is reduced from 160 ℃ to 122 ℃ and then maintained for 20 minutes, the temperature is reduced to 30 ℃ and maintained for 1 minute;

iii) heating to 117 ℃ which is 5 ℃ lower than 122 ℃, then holding for 20 minutes, reducing the temperature to 30 ℃ and holding for 1 minute;

iv) repeating until the heating temperature becomes 52 ℃ while gradually decreasing the heating temperature at the same temperature rising rate, holding time and cooling temperature with the (n +1) th heating temperature being 5 ℃ lower than the nth heating temperature; and

v) finally, the temperature is raised from 30 ℃ to 160 ℃.

Fig. 2 shows a temperature profile of an SSA analysis according to an embodiment of the present invention.

Referring to FIG. 2, the polyolefin was first heated to 160 ℃ using a differential scanning calorimeter (equipment name: DSC8000, manufacturing company: Perkinelmer) and then held for 30 minutes to remove all the heat history before measuring the sample. The temperature was decreased from 160 ℃ to 122 ℃, then held for 20 minutes, then decreased to 30 ℃ and held for 1 minute, and then increased again.

Subsequently, after heating to a temperature (117 ℃) 5 ℃ lower than the first heating temperature of 122 ℃, the temperature was maintained for 20 minutes, lowered to 30 ℃ and maintained for 1 minute, and then raised again. Thus, while gradually decreasing the heating temperature with the same holding time and cooling temperature using the (n +1) th heating temperature 5 ℃ lower than the nth heating temperature, this process was repeated up to 52 ℃.

Wherein the temperature rise speed and the temperature drop speed are respectively controlled at 20 ℃/min. Finally, in order to quantitatively analyze the distribution of crystals formed by repeating the heating-annealing-quenching, while the temperature was increased from 30 ℃ to 160 ℃ at a temperature-increasing rate of 10 ℃/min, the change in heat was observed to measure a thermogram.

Thus, if the heating of the polyolefin of the invention is repeated by the SSA processAnnealing-quenching followed by raising the temperature, with peaks appearing according to the temperature, so as to obtain ethylene sequences of different thicknesses, and thus, a weighted average (L) of the ethylene sequences_w) And arithmetic mean (L)_n) The calculation can be made by the following equations 2 and 3:

[ equation 2]

In the case of the equation 2, the,

[ equation 3]

In the case of the equations 2 and 3,

S_iis the area of each melting peak measured in the SSA thermogram, an

L_iIs the ASL (average ethylene sequence length) corresponding to each melting peak in the SSA thermogram.

Among them, ASL can be calculated from SSA thermograms with reference to Journal of Polymer Science Part B: Polymer Physics.2002, vol.40,813-821, and Journal of the Korea Chemical Society 2011, Vol.55, No. 4.

L calculated by the above method_wAnd L_nRatio (L) of_w/L_n) For ethylene sequence heterogeneity (I), a larger value of I indicates a more non-uniform distribution of platelets in the polymer chain and a higher SCB content.

The polyolefin according to one embodiment of the present invention may have a heterogeneity (I) of 1.25 or more, or 1.26 or more, or 1.27 or more, and 1.40 or less, or 1.38 or less, or 1.35 or less, or 1.32 or less.

The higher the heterogeneity, the more excellent the dart drop impact strength, and therefore, since the polyolefin of the present invention has heterogeneity of the above range, it can exhibit improved transparency and dart drop impact strength as compared with the existing polyolefin having the same density range.

Although the low-density polyolefin can improve dart impact strength, melt strength deteriorates, thus making it difficult to produce a stable blown film. However, the polyolefins of the present invention may achieve improved dart impact strength compared to existing polyolefin products having the same density.

Also, the polyolefin according to one embodiment of the present invention may have a Melt Index (MI) measured according to ASTM D1238 at a temperature of 190 ℃ and a load of 2.16kg of 0.5 to 1.5g/10min_2.16) While satisfying the above properties. More particularly, Melt Index (MI)_2.16) It may be 0.5g/10min or more, or 0.7g/10min or more, or 0.8g/10min or more, or 0.9g/10min or more, and 1.5g/10min or less, or 1.4g/10min or less, or 1.3g/10min or less.

Also, the polyolefin according to an embodiment of the present invention may have a haze of 11% or less of a polyolefin film (BUR 2.3, film thickness of 55 to 65 μm) prepared using a film maker measured according to ISO 13468. More particularly, the haze of the polyolefin according to an embodiment of the present invention may be 11% or less, or 10.5% or less, or 10% or less. The lower limit value is not particularly limited, and may be, for example, 4% or more, 5% or more, 6% or more, or 7% or more.

After preparing a polyolefin film (BUR 2.3, film thickness of 55 to 65 μm) using a film maker, the polyolefin according to one embodiment of the present invention may have a dart impact strength of 850g or more, or 900g or more, or 950g or more measured according to ASTM D1709[ method a ]. The upper limit is not particularly limited, and may be 1500g or less, 1400g or less, 1300g or less, or 1200g or less, for example.

Also, the polyolefin according to one embodiment of the present invention may have a weight average molecular weight (Mw) of 70,000 to 140,000 g/mol. More preferably, the weight average molecular weight may be 80,000g/mol or more, or 90,000g/mol or more, and 130,000g/mol or less, or 120,000g/mol or less.

The weight average molecular weight (Mw) is measured using Gel Permeation Chromatography (GPC), and it means a generally-calibrated value using a polystyrene standard, and may be appropriately controlled in consideration of the use or application field of polyolefin.

Meanwhile, the polyolefin according to one embodiment of the present invention having the above properties may be prepared by a method comprising the step of polymerizing an olefin monomer in the presence of a hybrid supported metallocene compound as a catalytically active component.

More particularly, although not limited thereto, the polyolefin of the present invention may be prepared as follows: polymerizing olefin monomers in the presence of a hybrid supported metallocene catalyst comprising: a first metallocene compound selected from one or more of the compounds represented by the following chemical formula 1; a second metallocene compound selected from one or more of the compounds represented by the following chemical formula 2; and a support supporting the first and second metallocene compounds:

[ chemical formula 1]

In the chemical formula 1, the first and second,

Q₁and Q₂Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkoxyalkyl, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl;

T₁is carbon, silicon or germanium;

M₁is a group 4 transition metal;

X₁and X₂Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, nitro, amino, C1-C20 alkylsilyl, C1-C20 alkoxy, or C1-C20 sulfonate group;

R₁to R₁₄Are identical or different from one another and are each independently hydrogen, halogen, C1-C20 alkyl, C1-C20 haloalkyl, C2-C20 alkenyl, C1-C20 alkylsilyl, C1-C20 silylalkyl, C1-C20 alkoxysilylAlkyl, C1-C20 alkoxy, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl, or R₁To R₁₄Two or more adjacent groups of (a) are linked to each other to form a substituted or unsubstituted aliphatic or aromatic ring;

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

Q₃and Q₄Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkoxyalkyl, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl;

T₂is carbon, silicon or germanium;

M₂is a group 4 transition metal;

X₃and X₄Identical to or different from each other and are each independently halogen, C1-C20 alkyl, C2-C20 alkenyl, C6-C20 aryl, nitro, amino, C1-C20 alkylsilyl, C1-C20 alkoxy, or C1-C20 sulfonate group;

R₁₅to R₂₈Are identical to or different from one another and are each independently hydrogen, halogen, C1-C20 alkyl, C1-C20 haloalkyl, C2-C20 alkenyl, C2-C20 alkoxyalkyl, C1-C20 alkylsilyl, C1-C20 silylalkyl, C1-C20 alkoxysilyl, C1-C20 alkoxy, C6-C20 aryl, C7-C20 alkylaryl, or C7-C20 arylalkyl, with the proviso that R1-C20 alkoxy is hydrogen, halogen, C1-C20 alkyl, C3626-C20 haloalkyl, C1-C7 arylalkyl₂₀And R₂₄Are identical or different from one another and are each independently C1 to C20 alkyl, or R₁₅To R₂₈Two or more adjacent groups in (a) are linked to each other to form a substituted or unsubstituted aliphatic or aromatic ring.

In the hybrid supported metallocene catalyst, the substituents of chemical formulas 1 and 2 will be explained in detail.

The C1 to C20 alkyl group may include a straight chain or branched chain alkyl group, and specifically, may include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl and the like, but is not limited thereto.

The C2 to C20 alkenyl group may include a straight chain or branched alkenyl group, and particularly, may include allyl, vinyl, propenyl, butenyl, pentenyl and the like, but is not limited thereto.

The C6 to C20 aryl group may include a monocyclic or fused ring aryl group, and particularly, it may include a phenyl group, a biphenyl group, a naphthyl group, a phenanthryl group, a fluorenyl group, and the like, but is not limited thereto.

The C1 to C20 alkoxy group may include methoxy, ethoxy, phenoxy, cyclohexyloxy and the like, but is not limited thereto.

The C2 to C20 alkoxyalkyl group is a functional group in which one or more hydrogen atoms of the above alkyl group are substituted with an alkoxy group, and in particular, it may include alkoxyalkyl groups such as methoxymethyl group, methoxyethyl group, ethoxymethyl group, isopropoxymethyl group, isopropoxyethyl group, isopropoxyhexyl group, tert-butoxymethyl group, tert-butoxyethyl group, tert-butoxyhexyl group and the like; or aryloxyalkyl groups such as phenoxyhexyl and the like, but are not limited thereto.

C1 to C20 alkylsilyl or C1 to C20 alkoxysilyl is wherein-SiH₃A functional group in which 1 to 3 hydrogen atoms of (a) are substituted with the above alkyl group or alkoxy group, and in particular, may include an alkylsilyl group such as methylsilyl group, dimethylsilyl group, trimethylsilyl group, dimethylethylsilyl group, diethylmethylsilyl group or dimethylpropylsilyl group; alkoxysilyl groups such as methoxysilyl group, dimethoxysilyl group, alkoxysilyl groups such as trimethoxysilyl group and dimethoxyethoxysilyl group; alkoxyalkyl silyl groups such as methoxydimethylsilyl group, diethoxymethylsilyl group or dimethoxypropylsilyl group, etc., but are not limited thereto.

The C1 to C20 silylalkyl groups are functional groups in which one or more hydrogen atoms of the above alkyl groups are substituted with a silyl group, and in particular, may include-CH₂-SiH₃Methyl silylmethyl, or dimethylethoxysilylpropyl, and the like, but is not limited thereto.

Halogen may be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

The sulfonate group having-O-SO₂-R 'wherein R' may be C1-C20 alkyl. In particular, the C1 to C20 sulfonate group may include a methanesulfonate group or a benzenesulfonate group, etc., but is not limited thereto.

Also, as used herein, the description "two adjacent substituents are linked to each other to form an aliphatic or aromatic ring" means that the atoms of the two substituents and the atoms to which the two substituents are bonded are linked to each other to form a ring. In particular as in which-NR_aR_bor-NR_a'R_b'R of (A) to (B)_aAnd R_bOr R_a'And R_b'As examples of the case where they are linked to each other to form an aliphatic ring, there may be mentioned piperidyl and the like, and as a compound wherein-NR is_aR_bor-NR_a'R_b'R of (A) to (B)_aAnd R_bOr R_a'And R_b'As examples of the case where they are linked to each other to form an aromatic ring, there can be mentioned an azole group and the like.

The above substituents may optionally be selected from hydroxy; halogen; alkyl or alkenyl, aryl, alkoxy; alkyl or alkenyl groups including one or more group 14 to 16 heteroatoms, aryl groups, alkoxy groups; a silane group; an alkylsilyl or alkoxysilyl group; a phosphine group; a phosphorus group; a sulfonate group; and a sulfone group.

As the group 4 transition metal, titanium (Ti), zirconium (Zr), hafnium (Hf), etc. may be mentioned, but not limited thereto.

With the hybrid supported catalyst, excellent dart impact strength can be ensured by the heterogeneity of the sheet-like distribution while maintaining the transparency of the polyolefin, and therefore, a polyolefin having high processability, particularly excellent melt-blown processability, can be produced.

In particular, in the hybrid supported catalyst according to one embodiment of the present invention, the first metallocene compound contains long-chain branches and easily produces a low molecular weight polyolefin, and the second metallocene compound contains a small amount of long-chain branches compared to the first metallocene compound and easily produces a relatively high molecular weight polyolefin. In particular, when the polymer contains many long-chain branches and has a large molecular weight, the melt strength is increased, but the first metallocene compound contains many long-chain branches and has a low molecular weight, there is a limitation in improving the bubble stability.

In the present invention, a first metallocene compound that contains relatively many long chain branches and produces a low molecular weight polymer is supported together with a second metallocene compound that contains relatively many short chain branches and produces a high molecular weight polymer, thereby maintaining excellent transparency and improving melt strength. By supporting both metallocene compounds together, the position of the long-chain branch present in the polymer is relatively oriented to a low molecular weight, and hence transparency is not deteriorated.

In particular, the hybrid supported catalyst of the present invention is characterized in that the long-chain branch generated from the first metallocene compound of chemical formula 1 and the long-chain branch generated from the second metallocene compound of chemical formula 2 are entangled with each other at a molecular level. Due to the entanglement between the long chain branches, a great force is required to release the molten state. Since the melt strength is not improved when the homopolymer produced from each catalyst is melt-blended, the improvement of the melt strength is effective when entanglement occurs from the polymerization step by the hybrid supported catalyst.

More particularly, in the hybrid supported catalyst according to one embodiment of the present invention, the first metallocene compound represented by chemical formula 1 comprises a cyclopentadienyl ligand and a tetrahydroindenyl ligand, wherein the ligands are bonded through-Si (Q)₁)(Q₂) -crosslinking and the presence of M between the ligands₁(X₁)(X₂). By polymerization using a catalyst having such a structure, a polymer containing a small amount of long-chain branches, a relatively narrow molecular weight distribution (PDI, MWD, Mw/Mn), and a Melt Flow Rate Ratio (MFRR) can be obtained.

In particular, in the structure of the metallocene compound represented by chemical formula 1, for example, a cyclopentadienyl ligand may have an influence on olefin polymerization activity.

In particular, R in the cyclopentadienyl ligand₁₁To R₁₄In the case of each independently C1 to C20 alkyl groups, C1 to C20 alkoxy groups, or C2 to C20 alkenyl groups, the catalyst obtained from the metallocene compound of chemical formula 1 may exhibit higher activity in olefin polymerization processes, and at R₁₁To R₁₄Each independently being methyl, ethyl, propyl or butyl, the hybrid supported catalyst may exhibit higher activity during polymerization of olefin monomers.

Also, the metallocene compound represented by chemical formula 1 has an unshared electron pair capable of acting as a lewis base of the tetrahydroindenyl ligand to exhibit stable and high polymerization activity, and the tetrahydroindenyl ligand can control the degree of steric hindrance effect according to the kind of the substituted functional group, and thus easily control the molecular weight of the polyolefin prepared.

In particular, in chemical formula 1, R₁May be hydrogen, C1 to C20 alkyl, C1 to C20 alkoxy, or C2 to C20 alkenyl. More particularly, in chemical formula 1, R₁May be hydrogen or C1 to C20 alkyl, and R₂To R₁₀May each independently be hydrogen. In this case, the hybrid supported catalyst can provide polyolefins having excellent processability.

And, in the structure of the metallocene compound represented by chemical formula 1, the cyclopentadienyl ligand and the tetrahydroindenyl ligand are represented by — Si (Q)₁)(Q₂) -linked, thus exhibiting excellent stability. To ensure the effect more effectively, Q₁And Q₂May each independently be a C1 to C20 alkyl group, or a C6 to C20 aryl group. More particularly, one may use a compound in which Q is₁And Q₂Metallocene compounds which are each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, phenyl, or benzyl.

In the structure of the metallocene compound represented by chemical formula 1, M existing between a cyclopentadienyl ligand and a tetrahydroindenyl ligand₁(X₁)(X₂) May have an effect on the storage stability of the metal complex. To ensure the effect more effectively, X₁And X₂May each independently be halogen, C1 to C20 alkyl, orC1 to C20 alkoxy. More particularly, X₁And X₂May independently be F, Cl, Br or I, and M₁Can be Ti, Zr or Hf; zr or Hf; or Zr.

For example, as the first metallocene compound capable of providing a polyolefin showing more improved dart impact strength and high short chain branch content and having excellent blown film processability, there can be mentioned a compound represented by the following structural formula, but not limited thereto.

The first metallocene compound represented by chemical formula 1 may be synthesized by applying a known reaction. Specifically, it can be prepared by linking a tetrahydroindenyl derivative and a cyclopentadiene derivative with a bridge compound to prepare a ligand compound, and then introducing a metal precursor compound for metallation, but the method is not limited thereto, and for a more detailed synthetic method, reference may be made to examples.

Meanwhile, in the hybrid supported catalyst according to one embodiment of the present invention, the metallocene compound represented by chemical formula 2 has a cyclopentadienyl ligand and a substituent (R) at a specific position₂₀And R₂₄) Wherein said different ligands are through-Si (Q)₃)(Q₄) -crosslinking, and M₂(X₃)(X₄) Between the different ligands. If the metallocene compound having such a specific structure is activated by an appropriate method and used as a catalyst for olefin polymerization, long-chain branches can be generated. Thus, by introducing a substituent (R) at a specific position of the indene derivative of chemical formula 2, as compared with a metallocene compound comprising an unsubstituted indene compound or an indene compound substituted at other positions₂₀And R₂₄) The metallocene compound may have high polymerization activity.

In particular, the second metallocene compound represented by chemical formula 2 has a molecular weight of about 150,000 to 550,000 and has SCB by homopolymerization, and thus, when used in a hybrid catalyst, has a narrow molecular weight distribution and improves processability.

In particular, in the structure of the metallocene compound represented by chemical formula 2, the cyclopentadienyl ligand may have an influence on the olefin polymerization activity.

In particular, R in the cyclopentadienyl ligand₂₅To R₂₈In the case where each is independently hydrogen, a C1 to C20 alkyl group, a C2 to C20 alkoxyalkyl group, or a C6 to C20 aryl group, the catalyst obtained from the metallocene compound of chemical formula 2 may exhibit higher activity in the olefin polymerization process, and at R₂₅And R₂₈Each independently hydrogen, C1 to C20 alkyl, or C2 to C20 alkoxyalkyl, the hybrid supported catalysts can exhibit very high activity during polymerization of olefin monomers.

Also, in the structure of the metallocene compound represented by chemical formula 2, the indenyl ligand can control the degree of steric hindrance effect according to the kind of the substituted functional group, thereby easily controlling the molecular weight of the polyolefin prepared.

In particular, in order to increase the molecular weight, it is preferable to substitute phenyl at the 4-position of indenyl group, R at the para-position of phenyl group₂₀Is C1-C20 alkyl and the substituent R is in the 6-position of the indenyl group₂₄Is a C1 to C20 alkyl group. In particular, R₂₀And R₂₄May each independently be C1 to C4 alkyl, R₂₀Methyl, ethyl, n-propyl, isopropyl, etc. may be preferred, and R₂₄T-butyl may be preferred. In this case, the hybrid supported catalyst can provide polyolefins with excellent comonomer incorporation.

The remaining substituents of indenyl, R₁₅To R₁₉And R₂₁To R₂₃May each independently be hydrogen, halogen, C1 to C20 alkyl, C1 to C20 haloalkyl, C2 to C20 alkenyl, C2 to C20 alkoxyalkyl, C1 to C20 alkylsilyl, C1 to C20 silylalkyl, C1 to C20 alkoxysilyl, C1 to C20 alkoxy, C6 to C20 aryl, C7 to C20 alkylaryl, or C7 to C20 arylalkyl.

And, in the structure of the metallocene compound represented by chemical formula 2, the cyclopentadienyl ligand and the indenyl ligand are represented by-Si (Q)₃)(Q₄) -linked, thus exhibiting excellent stability. To ensure the effect more effectively, Q₃And Q₄May each independently be a C1 to C20 alkyl group or a C2 to C20 alkoxyalkyl group. More specifically, a structure in which Q is₃And Q₄A metallocene compound which is each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, methoxymethyl, methoxyethyl, ethoxymethyl, isopropoxymethyl, isopropoxyethyl, isopropoxyhexyl, tert-butoxymethyl, tert-butoxyethyl or tert-butoxyhexyl.

Particularly, in the metallocene compound represented by chemical formula 2, cyclopentadiene (Cp) or-Si (Q)₃)(Q₄) The substituent or substituents of the silyl group may be an alkoxyalkyl group of C2 to C20, more preferably, an isopropoxyethyl group, an isopropoxyhexyl group, a tert-butoxyethyl group, a tert-butoxyhexyl group and the like.

The C2 to C20 alkoxyalkyl group may affect the comonomer incorporation of an α -olefin comonomer such as 1-butene or 1-hexene, and in the case where the alkoxyalkyl group has a short alkyl chain of C4 or less, the comonomer incorporation of the α -olefin comonomer may be reduced while maintaining the overall polymerization activity, and thus, a polyolefin having a controlled copolymerization degree may be prepared without reducing other properties.

And, in the structure of the metallocene compound represented by chemical formula 2, M existing between the cyclopentadienyl ligand and the tetrahydroindenyl ligand₂(X₃)(X₄) May have an effect on the storage stability of the metal complex. To ensure the effect more effectively, X₃And X₄May each independently be halogen, C1 to C20 alkyl, or C1 to C20 alkoxy. More specifically, X₃And X₄May independently be F, Cl, Br or I, and M₂Can be Ti, Zr or Hf; zr or Hf; or Zr.

Meanwhile, as a specific example of the second metallocene compound represented by chemical formula 2, a compound represented by the following structural formula may be mentioned, but the present invention is not limited thereto.

As explained, since the hybrid supported metallocene catalyst of one embodiment includes the first and second metallocene compounds, it can prepare polyolefins having excellent processability, particularly excellent dart impact strength.

In particular, the molar ratio of the first metallocene compound and the second metallocene compound can be about 1:1 to 10:1, preferably about 1.2:1 to 7.5:1, more preferably 1.5:1 to 7.0:1, or 1.8:1 to 6.5: 1. The mixing molar ratio of the first metallocene compound and the second metallocene compound may be 1:1 or more to control the molecular weight and the amounts of SCB, LCB to satisfy both the performance and the processability, and it may be 10:1 or less to ensure the processability.

Meanwhile, since the first and second metallocene compounds have the above structural features, they can be stably supported in a carrier.

As the support, a support having a hydroxyl group or a siloxane group on the surface can be used. In particular, those which are dried at high temperature to remove moisture on the surface and thus contain highly reactive hydroxyl groups or siloxane groups can be used as the carrier.

More specifically, as the support, silica, alumina, magnesia or a mixture thereof may be used, wherein silica may be more preferable. The support may be dried at elevated temperatures, for example, high temperature dried silica, silica-alumina or silica-magnesia and the like may be used, which may typically comprise an oxide, carbonate, sulphate, nitrate component, for example Na₂O、K₂CO₃、BaSO₄And Mg (NO)₃)₂And the like.

The drying temperature of the support may preferably be about 200 to 800 ℃, more preferably about 300 to 600 ℃, and most preferably about 300 to 400 ℃. If the drying temperature of the support is less than about 200 deg.c, the surface moisture may react with the co-catalyst, and if it is greater than about 800 deg.c, the pores on the surface of the support may be combined to reduce the surface area, and the surface hydroxyl groups may disappear while leaving only the siloxane groups, and thus, the reaction sites with the co-catalyst may be reduced.

The amount of hydroxyl groups on the surface of the support may preferably be about 0.1 to 10mmol/g, and more preferably about 0.5 to 5 mmol/g. The amount of hydroxyl groups on the surface of the support can be controlled by the preparation method and conditions of the support or drying conditions, such as temperature, time, vacuum, spray drying, or the like.

If the amount of hydroxyl groups is less than about 0.1mmol/g, the reaction sites with the cocatalyst may be rare, whereas if it is more than about 10mmol/g, they may be derived from moisture present on the surface of the support particle other than the hydroxyl groups, which is not preferable.

Also, in the hybrid supported metallocene catalyst of one embodiment, the cocatalyst which is supported together on the support to activate the metallocene compound is not particularly limited as long as it is an organometallic compound including a group 13 metal and can be used for olefin polymerization in the presence of a common metallocene catalyst.

In particular, the cocatalyst compound may include one or more of an aluminum-containing first cocatalyst of the following chemical formula 3 and a borate-based second cocatalyst of the following chemical formula 4.

[ chemical formula 3]

R_a-[Al(R_b)-O]_n-R_c

In the chemical formula 3, the first and second,

R_a、R_band R_cAre the same or different from each other and are each independently hydrogen, halogen, C1 to C20 hydrocarbyl, or C1 to C20 hydrocarbyl substituted with halogen;

n is an integer of 2 or more;

[ chemical formula 4]

T⁺[BG₄]^-

In chemical formula 4, T⁺Is +1 valent polyatomic ion, B is boron in oxidation state of +3, and G is independently selected from hydrogen anionsAn ionic group, a dialkylamine group, a halogen anionic group, an alkoxy group, an aryloxy group, a hydrocarbyl group, a halogenated hydrocarbyl group, and a halogen-substituted hydrocarbyl group, and G has 20 carbons or less, with the proviso that G is a halogen anionic group at one or fewer positions.

The first cocatalyst of chemical formula 3 may be an alkylaluminoxane-based compound in which repeating units are combined in a linear, circular or network shape, and specific examples of the first cocatalyst may include Methylaluminoxane (MAO), ethylaluminoxane, isobutylaluminoxane, butylaluminoxane or the like.

And, the second cocatalyst of chemical formula 4 may be a borate-based compound in the form of a tri-substituted ammonium salt or dialkyl ammonium salt or tri-substituted phosphonium salt. As specific examples of the second cocatalyst, mention may be made of borate-based compounds in the form of trisubstituted ammonium salts, such as trimethylammoniumtetraphenylborate, methyldioctadecylammonium tetraphenylborate, triethylammoniumtetraphenylborate, tripropylammoniumtetraphenylborate, tri (N-butyl) ammoniumtetraphenylborate, methyltetradecylacetylammonium tetraphenylborate, N-dimethylaniliniumtetraphenylborate, N-diethylaniliniumtetraphenylborate, N-dimethyl (2,4, 6-trimethylanilinium) tetraphenylborate, trimethylammoniumtetrakis (pentafluorophenyl) borate, methyldietetrakis (tetradecyl) ammoniumtetrakis (pentafluorophenyl) borate, methyldioctadecylammonium tetrakis (pentafluorophenyl) borate, triethylammoniumtetrakis (pentafluorophenyl) borate, tripropylammoniumtetrakis (pentafluorophenyl) borate, Tri (N-butyl) ammonium tetrakis (pentafluorophenyl) borate, tri (sec-butyl) ammonium tetrakis (pentafluorophenyl) borate, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, N-diethylanilinium tetrakis (pentafluorophenyl) borate, N-dimethyl (2,4, 6-trimethylanilinium) tetrakis (pentafluorophenyl) borate, trimethylammonium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, triethylammonium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, tripropylammonium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, tri (N-butyl) ammonium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, dimethyl (tert-butyl) ammonium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, N-dimethylanilinium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, N-diethylanilinium tetrakis (2,3,4, 6-tetrafluorophenyl) borate and N, N-dimethyl- (2,4, 6-trimethylanilinium) tetrakis (2,3,4, 6-tetrafluorophenyl) borate; borate-based compounds in the form of dialkylammonium salts such as dioctadecylammoniumtetrakis (pentafluorophenyl) borate, ditetradecylammonium tetrakis (pentafluorophenyl) borate and dityclohexylammoniumtetrakis (pentafluorophenyl) borate; and borate-based compounds in the form of tri-substituted phosphonium salts such as triphenylphosphonium tetrakis (pentafluorophenyl) borate, methyldioctadecylphosphonium tetrakis (pentafluorophenyl) borate and tris (2, 6-dimethylphenyl) phosphonium tetrakis (pentafluorophenyl) borate.

In the hybrid supported metallocene catalyst of an embodiment, a mass ratio of the total transition metal contained in the first metallocene compound and the second metallocene compound to the support may be 1:10 to 1: 1000. When the support and the metallocene compound are contained in the above mass ratio, an optimum shape can be exhibited.

Also, the mass ratio of the cocatalyst compound to the support may be 1:1 to 1: 100. When the cocatalyst and the support are contained in the above-mentioned mass ratio, the activity and the polymer fine structure can be optimized.

The hybrid supported metallocene catalyst of one embodiment may be used in the polymerization of olefin monomers. Also, the hybrid supported metallocene catalyst may be subjected to a contact reaction with an olefin monomer and prepared as a prepolymerized catalyst, and for example, the catalyst may be separately contacted with an olefin monomer such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, etc. and prepared as a prepolymerized catalyst.

Meanwhile, the hybrid supported metallocene catalyst of one embodiment may be prepared by a method comprising the steps of: the cocatalyst is supported on the support, and the first and second metallocene compounds are supported on the cocatalyst-supporting support.

Wherein the first metallocene and the second metallocene compound may be sequentially supported in sequence, or both may be supported together. The order of the supporting is not limited, but the second metallocene catalyst having a relatively poor morphology may be first supported to improve the shape of the hybrid supported metallocene catalyst, and thus, after the second metallocene catalyst is supported, the first metallocene catalyst may be sequentially supported.

In the above-mentioned method, the loading conditions are not particularly limited and may be carried out under conditions well known to those of ordinary skill in the art. For example, a high temperature load and a low temperature load may be suitably used, and for example, the load temperature may be about-30 ℃ to 150 ℃, preferably room temperature (about 25 ℃) to about 100 ℃, and more preferably room temperature to about 80 ℃. The supporting time may be appropriately controlled according to the amount of the metallocene compound to be supported. The supported catalyst for the reaction may be used as it is after removing the reaction solvent by filtration or vacuum distillation, and subjected to Soxhlet filtration with an aromatic hydrocarbon (e.g., toluene) as required.

Also, the supported catalyst can be prepared in a solvent or without a solvent. As the solvent that can be used, there can be mentioned an aliphatic hydrocarbon solvent (such as hexane or pentane), an aromatic hydrocarbon solvent (such as toluene or benzene), a hydrocarbon solvent substituted with a chlorine atom (such as dichloromethane), an ether-based solvent (such as diethyl ether or THF), acetone, ethyl acetate and the like, and hexane, heptane, toluene or dichloromethane can be preferably used.

Meanwhile, according to another embodiment of the present invention, there is provided a method for preparing a polyolefin, which includes the step of polymerizing an olefin monomer in the presence of the hybrid supported metallocene catalyst.

And, the olefin monomer may be one or more selected from the group consisting of ethylene, 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-eicosenyl, norbornene, norbornadiene, ethylidene norbornene, phenylnorbornene, vinyl norbornene, dicyclopentadiene, 1, 4-butadiene, 1, 5-pentadiene, 1, 6-hexadiene, styrene, α -methylstyrene, divinylbenzene and 3-chloromethylstyrene.

For the polymerization of the olefin monomer, various polymerization methods known as polymerization of olefin monomers, such as continuous solution polymerization, bulk polymerization, suspension polymerization, slurry polymerization, emulsion polymerization, or the like, can be used. The polymerization reaction may be carried out at a pressure of about 1 to 100 bar or about 10 to 80 bar at a temperature of about 25 to 500 ℃, or about 25 to 200 ℃, or about 50 to 150 ℃.

Also, in the polymerization reaction, the hybrid supported metallocene catalyst may be used while being dissolved or diluted in a solvent such as pentane, hexane, heptane, nonane, decane, toluene, benzene, dichloromethane, chlorobenzene, or the like. Wherein the solvent may be treated with a small amount of an aluminum alkyl to remove small amounts of water or air that may adversely affect the catalyst.

Also, the polyolefin prepared by the above method can exhibit high dart impact strength, low density, and excellent transparency.

In particular, the density of the polyolefin may be 0.915g/cm when analyzed by SSA (sequential self-nucleation and annealing)³To 0.930g/cm³And the ethylene sequence heterogeneity (I) is 1.25 to 1.40.

Also, the polyolefin can exhibit a Melt Index (MI) of 0.5 to 1.5g/10min measured according to ASTM D1238 at a temperature of 190 ℃ and a load of 2.16kg_2.16)。

And, after preparing a polyolefin film (BUR 2.3, film thickness of 55 to 65 μm) using a film maker, the polyolefin may exhibit a film haze of 11% or less measured according to ISO 13468.

Also, after a polyolefin film (BUR 2.3, film thickness of 55 to 65 μm) was prepared using a film maker, the polyolefin could exhibit a dart impact strength of 850g or more measured according to ASTM D1709[ method A ].

Also, if the polyolefin is, for example, an ethylene- α -olefin copolymer, preferably a copolymer of ethylene and 1-butene, or a copolymer of ethylene and 1-hexene, the above properties can be more suitably satisfied.

Hereinafter, preferred embodiments are given to better understand the present invention. However, these examples are given only as illustrations of the present invention, and the scope of the present invention is not limited thereto.

< example >

< example for Synthesis of metallocene Compound >

Synthesis example 1: first cyclopentadieneMetal compound

Preparation of 1-1 ligand compounds

Tetramethylcyclopentadiene (TMCP) was lithiated with a solution of n-BuLi (1 equivalent) in THF (0.4M), then filtered and used as the tetramethylcyclopentyl-Li salt (TMCP-Li salt). The indene was lithiated with n-BuLi (1 equivalent) in hexane (0.5M), then filtered and used as the indene-Li salt (Ind-Li salt). 50mmol of tetramethylcyclopentyl-Li salt (TMCP-Li salt) and 100mL of Tetrahydrofuran (THF) were introduced under Ar into a 250mL Schlenk flask. 1 equivalent of dichloromethyl- (isopropyl) silane was added at-20 ℃. After about 6 hours, 3 mol% of CuCN and Ind-Li salt (50mmol, MTBE 1M solution) were added at-20 ℃ and reacted for about 12 hours. The organic layer was separated with water and hexane to obtain the ligand.

1-2 preparation of metallocene compounds

To a dry 250mL Schlenk flask under Ar was introduced 50mmol of the ligand compound synthesized in 1-1 and dissolved in about 100mL of MTBE and 2 equivalents of n-BuLi were added dropwise at-20 ℃. After about 16 hours of reaction, the ligand-Li solution was added to ZrCl₄(THF)₂(50mmol, MTBE 1M solution). After about 16 hours of reaction, the solvent was removed, and the reaction mixture was dissolved in dichloromethane (MC) and filtered to remove LiCl. The solvent of the filtrate was removed, about 50mL of MTBE and about 100mL of hexane were added, and the solution was stirred for about 2 hours and then filtered to obtain a solid metallocene catalyst precursor.

The obtained metallocene catalyst precursor (20mmol), 60mL of DCM and 5 mol% of Pd/C catalyst were introduced into a high pressure stainless steel (sus) reactor under argon atmosphere. The argon gas in the high-pressure reactor was replaced with hydrogen gas 3 times, and the pressure was filled with hydrogen gas so that the pressure became about 20 bar. The reaction was completed by stirring at 35 ℃ for about 24 hours. The interior of the reactor was replaced with argon and the DCM solution was then transferred to a schlenk flask under an argon atmosphere. The solution was passed through celite under argon to remove the Pd/C catalyst, and the solvent was dried to obtain a solid catalyst precursor.

¹H NMR(500MHz,C6D6):0.62(3H,s),0.98(3H,d),1.02(3H,d),1.16(2H,dd),1.32-1.39(3H,m),1.78(3H,s),1.81(3H,s),1.84-1.94(3H,m),2.01(3H,s),2.03(1H,m),2.04(3H,s),2.35(2H,m),2.49-2.55(1H,m),3.13-3.19(1H,m),5.27(1H,d),6.75(1H,d).

Synthesis example 2: a first metallocene compound

Preparation of 2-1 ligand compounds

Tetramethylcyclopentadiene (TMCP) was lithiated with a solution of n-BuLi (1 equivalent) in THF (0.4M), then filtered and used as the tetramethylcyclopentyl-Li salt (TMCP-Li salt). The indene was lithiated with n-BuLi (1 equivalent) in hexane (0.5M), then filtered and used as the indene-Li salt (Ind-Li salt). 50mmol of tetramethylcyclopentyl-Li salt (TMCP-Li salt) and 100mL of Tetrahydrofuran (THF) were introduced into a 250mL Schlenk flask under Ar. 1 equivalent of dichloromethylphenylsilane was added at-20 ℃. After about 6 hours, 3 mol% of CuCN and Ind-Li salt (50mmol, MTBE 1M solution) were added at-20 ℃ and reacted for about 12 hours. The organic layer was separated with water and hexane to obtain the ligand.

2-2 preparation of metallocene compounds

To a dry 250mL Schlenk flask under Ar was introduced 50mmol of the ligand compound synthesized in 2-1 and dissolved in about 100mL of MTBE and 2 equivalents of n-BuLi were added dropwise at-20 ℃. After about 16 hours of reaction, the ligand-Li solution was added to ZrCl₄(THF)₂(50mmol, MTBE 1M solution). After about 16 hours of reaction, the solvent was removed, and the reaction mixture was dissolved in dichloromethane (MC) and filtered to remove LiCl. The solvent of the filtrate was removed, about 50mL of MTBE and about 100mL of hexane were added, and the solution was stirred for about 2 hours and then filtered to obtain a solid metallocene catalyst precursor.

The obtained metallocene catalyst precursor (20mmol), 60mL of DCM and 5 mol% of Pd/C catalyst were introduced into a high pressure stainless steel (sus) reactor under argon atmosphere. The argon gas in the high-pressure reactor was replaced with hydrogen gas 3 times, and the pressure was filled with hydrogen gas so that the pressure became about 20 bar. The reaction was completed by stirring at 35 ℃ for about 24 hours. The interior of the reactor was replaced with argon and the DCM solution was then transferred to a schlenk flask under an argon atmosphere. The solution was passed through celite under argon to remove the Pd/C catalyst and the solvent was dried to obtain different stereoisomers of the metallocene compound (A, B form) in a ratio of 1.3: 1.

¹H NMR(500MHz,CDCl₃):

Form A0.88 (3H, s),1.43-1.50(1H, m),1.52-1.57(1H, m),1.60(3H, s),1.62-1.68(1H, m),1.87-1.95(1H, m),1.95-2.00(1H, m),2.00(3H, s),2.06(3H, s),2.08(3H, s),2.41-2.47(1H, m),2.72-2.78(1H, m),3.04-3.10(1H, m),5.62(1H, d),6.73(1H, d),7.49(3H, m),7.87(2H, m)

B form 0.99(3H, s),1.42(3H, s),1.60-1.67(2H, m),1.90-1.98(1H, m),1.95(3H, s),2.06(3H, s),2.06-2.10(1H, m),2.11(3H, s),2.44-2.49(1H, m),2.66-2.70(1H, m),2.74-2.79(1H, m),3.02-3.11(1H, m),5.53(1H, d),6.74(1H, d),7.48(3H, m),7.88(2H, m).

Synthesis example 3: a first metallocene compound

Preparation of 3-1 ligand compounds

In a dry 250mL Schlenk flask, tetramethylcyclopentadiene (TMCP, 6.0mL, 40mmol) was dissolved in THF (60mL) and the solution was cooled to-78 ℃. Subsequently, n-BuLi (2.5M, 17mL, 42mmol) was slowly added dropwise to the solution, and then the resulting solution was stirred at room temperature overnight.

Meanwhile, dichlorodimethylsilane (4.8mL, 40mmol) was dissolved in n-hexane in a separate 250mL Schlenk flask, and the solution was cooled to-78 ℃. Subsequently, the TMCP lithiation solution prepared above was slowly added to the solution. And, the obtained solution was stirred at room temperature overnight.

After that, the obtained solution was decompressed to remove the solvent. And, the obtained solid was dissolved in toluene and filtered to remove residual LiCl, thereby obtaining an intermediate (yellow liquid, 7.0g, 33mmol, 83% yield).

¹H NMR(500MHz,CDCl₃):0.24(6H,s),1.82(6H,s),1.98(6H,s),3.08(1H,s).

In a dry 250mL schlenk flask, indene (0.93mL, 8.0mmol) was dissolved in THF (30mL) and the solution was then cooled to-78 ℃. Subsequently, n-BuLi (2.5M, 3.4mL, 8.4mmol) was slowly added dropwise to the solution, and then, the resulting solution was stirred at room temperature for about 5 hours.

Meanwhile, the above synthesized intermediate (1.7g, 8.0mmol) was dissolved in THF in a separate 250mL schlenk flask and the solution was cooled to-78 ℃. Subsequently, the indene-lithiation solution prepared above was slowly added to the solution. And, the obtained solution was stirred at room temperature overnight to obtain a magenta solution.

Thereafter, water was poured into the reactor to terminate the reaction (quenching), and the organic layer was extracted from the mixture with diethyl ether. By passing¹H NMR confirmed the inclusion of dimethyl (indenyl) (tetramethylcyclopentadienyl) silane and different kinds of organic compounds in the organic layer. The organic layer was concentrated without purification and used for metallization.

Preparation of 3-2 metallocene compounds

In a 250mL Schlenk flask, the dimethyl (indenyl) (tetramethylcyclopentadienyl) silane (1.7g, 5.7mmol) synthesized above was dissolved in toluene (30mL) and MTBE (3.0 mL). Then, the solution was cooled to-78 ℃ and n-BuLi (2.5M, 4.8mL, 12mmol) was slowly added dropwise to the solution, and the resulting solution was stirred at room temperature overnight. However, a yellow solid was produced in the solution and there was no uniform stirring, so MTBE (50mL) and THF (38mL) were additionally introduced.

Meanwhile, ZrCl was placed in a separate 250mL Schlenk flask₄(THF)₂Dispersed in toluene and the resulting mixture cooled to-78 ℃. Followed byThereafter, the lithiated ligand solution prepared above was slowly introduced into the mixture. Then, the obtained mixture was stirred overnight.

Thereafter, the reaction product was filtered to obtain a yellow solid (1.3g, containing LiCl (0.48g), 1.8mmol), and the solvent was removed from the filtrate, followed by washing with n-hexane to obtain a yellow solid (320mg, 0.70mmol) in addition (total yield 44%).

¹H NMR(500MHz,CDCl₃):0.96(3H,s),1.16(3H,s),1.91(3H,s),1.93(3H,s),1.96(3H,s),1.97(3H,s),5.98(1H,d),7.07(1H,t),7.23(1H,d),7.35(1H,t),7.49(1H,d),7.70(1H,d).

Dimethylsilylene (tetramethylcyclopentadienyl) (indenyl) zirconium dichloride (1.049g, 2.3mmol) synthesized above was placed in a miniature bomb reactor in a glove box. Then, platinum oxide (52.4mg, 0.231mmol) was additionally put into the micro bomb reactor, the micro bomb reactor was assembled, and then anhydrous THF (30mL) was introduced into the micro bomb reactor using a cannula, and hydrogen was filled to a pressure of about 30 bar. Subsequently, the mixture contained in the micro bomb reactor was stirred at about 60 ℃ for about one day, and then the micro bomb reactor was cooled to room temperature, and hydrogen was replaced with argon while gradually reducing the pressure of the micro bomb reactor.

Meanwhile, diatomaceous earth dried in an oven at about 120 ℃ for about 2 hours was placed in a schlenk filter, and the reaction product of the minibomb reactor was filtered under argon using the same. By reacting PtO with diatomaceous earth₂The catalyst is removed from the reaction product. Subsequently, the reaction product from which the catalyst was removed was subjected to reduced pressure to remove the solvent, to obtain a pale yellow solid product (0.601g, 1.31mmol, Mw: 458.65 g/mol).

¹H NMR(500MHz,CDCl₃):0.82(3H,s),0.88(3H,s),1.92(6H,s),1.99(3H,s),2.05(3H,s),2.34(2H,m),2.54(2H,m),2.68(2H,m),3.03(2H,m),5.45(1H,s),6.67(1H,s).

Synthesis example 4: second metallocene Compound

Preparation of 4-1 ligand compounds

To a dry 250mL Schlenk flask was introduced 11.618g (40mmol) of 4- (4- (tert-butyl) phenyl) -2-isopropyl-1H-indene and 100mL of THF under argon. The ether solution was cooled to 0 ℃ and 18.4mL of nBuLi solution (2.5M, 46mmol in hexanes) were then slowly added dropwise. The temperature of the reaction mixture was slowly raised to room temperature, and then the mixture was stirred until the next day. In a separate 250mL schlenk flask, a solution of 12.0586g (40mmol, calculated purity 90%) of dichloromethyl ether silane and 100mL of hexane was prepared, the schlenk flask was cooled to-30 ℃, and then the lithiation solution was added dropwise thereto. After the addition was completed, the temperature of the mixture was slowly raised to room temperature, followed by stirring for one day. The next day, NaCp (2M in THF, 33.6mL) was added slowly and stirred for one day, then 50mL of water was introduced into the flask to quench, and the organic layer was separated and over MgSO₄And (5) drying. As a result, 23.511g (52.9mmol) of oil (purity/weight% based on NMR 92.97%, Mw 412.69) were obtained.

Preparation of 4-2 metallocene compounds

The ligand was introduced into a 250mL schlenk flask dried in an oven and dissolved in 80mL toluene and 19mL MTBE (160mmol, 4 equivalents) and then 2.1 equivalents of nBuLi solution (84mmol, 33.6mL) was added to carry out lithiation until the next day. In a glove box, 1 equivalent of ZrCl was added₄(THF)₂Into a 250mL schlenk flask, and diethyl ether was introduced to prepare a suspension. Both flasks were cooled to-20 ℃ and then the ligand anion was slowly added to the Zr suspension. After the introduction was completed, the temperature of the reaction mixture was slowly raised to room temperature. After stirring for one day, MTBE in the mixture was filtered with a schlenk filter under argon, and the resultant LiCl was removed. The remaining filtrate was removed by vacuum suction and pentane was added to a small amount of dichloromethane in the volume of the reaction solvent. Among them, the reason for adding pentane is that the solubility of the synthesized catalyst precursor in pentane is reduced and crystallization is promoted. The slurry was filtered under argon and the residue on top was analyzed by NMR separatelyFilter cake and filtrate to confirm whether the catalyst was synthesized, and weighed and sampled in a glove box to confirm yield and purity (Mw 715.04).

¹H NMR(500MHz，CDCl₃)：0.60(3H，s)，1.01(2H，m)，1.16(6H，s)，1.22(9H，s)，1.35(4H，m)，1.58(4H，m)，2.11(1H，s)，3.29(2H，m)，5.56(1H，s)，5.56(2H，m)，5.66(2H，m)，7.01(2H，m)，7.40(3H，m)，7.98(2H，m)

Synthesis example 5: second metallocene Compound

Preparation of 5-1 ligand compounds

6-tert-butoxyhexyl chloride and sodium cyclopentadienide (2 eq.) are introduced into THF and stirred. After completion of the reaction, the reaction mixture was quenched with water and the excess cyclopentadiene was distilled off. To 4.45g (20mmol) of 6-t-butoxyhexylcyclopentadiene obtained by the above-mentioned method was added 27mL of toluene. The temperature was lowered to-20 ℃, 8.8mL of n-BuLi solution (2.5M in hexanes, 22mmol) was added dropwise, and the mixture was stirred at room temperature overnight.

To a dry 250mL Schlenk flask, 5.8g (20mmol) of 4- (4- (tert-butyl) phenyl) -2-isopropyl-1H-indene are introduced, and 33mL of MTBE are introduced. The temperature was lowered to-20 ℃ and 8.8mL of n-BuLi solution (2.5M in hexanes, 22mmol) was added dropwise, and the mixture was stirred at room temperature overnight. The temperature was lowered to-20 ℃ and 1.5 equivalents of dichlorodimethylsilane were introduced. The reaction mixture was stirred overnight and distilled to remove excess dichlorodimethylsilane.

The lithiated 6-tert-butoxyhexylcyclopentadiene solution was introduced into the flask and stirred overnight. By subjecting the ligand synthesized by the above-described method to a post-treatment, a ligand compound is obtained.

Preparation of 5-2 metallocene Compounds

11.4g (20mmol) of the ligand compound synthesized in 5-1 was dissolved in 50mL of toluene, and about 16.8mL of n-BuLi solution (2.5M in hexane, 42mmol) and the mixture was stirred overnight. 20mmol of ZrCl was introduced₄(THF)₂And stirred overnight, and after the reaction was complete, the reaction mixture was filtered to remove LiCl. All solvents were removed, then crystallized with hexane and purified to obtain different stereoisomers (A, B form) of the metallocene compound in a ratio of 1.3: 1.

¹H NMR(500MHz，C₆D₆)：

Form A0.58 (3H, s),0.55(3H, s),0.93-0.97(3H, m),1.12(9H, s),1.28(9H, s),1.27(3H, d),1.35-1.42(1H, m),1.45-1.62(4H, m),2.58-2.65(1H, m),2.67-2.85(2H, m),3.20(2H, t),5.42(1H, m),5.57(1H, m),6.60(1H, m),6.97(1H, dd),7.27(1H, d),7.39-7.45(4H, m),8.01(2H, dd)

B form 0.60(3H, s),0.57(3H, s),0.93-0.97(3H, m),1.11(9H, s),1.28(9H, s),1.32(3H, d),1.35-1.42(1H, m),1.45-1.62(4H, m),2.58-2.65(1H, m),2.67-2.85(2H, m),3.23(2H, t),5.24(1H, m),5.67(1H, m),6.49(1H, m),6.97(1H, dd),7.32(1H, d),7.39-7.45(4H, m),8.01(2H, dd)

Comparative synthesis example 1: second metallocene Compound

Preparation of 1-1 ligand compounds

Preparation of tert-butyl-O- (CH-O-) - (CH-O-using 6-chlorohexanol by the method described in the literature (Tetrahedron Lett.2951(1988))₂)₆-Cl and reaction with NaCp to obtain tert-butyl-O- (CH)₂)₆-C₅H₅(yield 60%, boiling point 80 ℃ C./0.1 mmHg).

1-2 preparation of metallocene compounds

Then, tert-butyl-O- (CH) is reacted at-78 deg.C₂)₆-C₅H₅Dissolved in THF and n-BuLi was slowly added thereto, then the temperature was raised to room temperature, and the mixture was allowed to react for 8 hours. The synthesized lithium salt solution was slowly added to ZrCl at-78 deg.C₄(THF)₂(1.70g, 4.50mmol)/THF (30ml) and the solution was allowed to react further at room temperature for 6 hours.

All volatiles were dried in vacuo and hexane was added to the oil obtainedThe liquid is filtered. The filtered solution was dried under vacuum, and then hexane was added to precipitate at low temperature (-20 ℃). The obtained precipitate was filtered at room temperature to obtain the compound [ tBu-O- (CH) as a white solid₂)₆-C₅H₄]₂ZrCl₂](yield 92%).

¹H NMR(300MHz,CDCl3):6.28(t,J＝2.6Hz,2H),6.19(t,J＝2.6Hz,2H),3.31(t,6.6Hz,2H),2.62(t,J＝8Hz),1.7-1.3(m,8H),1.17(s,9H)

Comparative synthesis example 2: second metallocene Compound

Preparation of 2-1 ligand compounds

3.7g (40mmol) of 1-chlorobutane were introduced into a dry 250mL Schlenk flask and dissolved in 40mL of THF. To this was slowly added 20mL of a solution of sodium cyclopentadienide in THF, and the mixture was stirred overnight. To the reaction mixture was added 50mL of water to quench, extracted with ether (50mL × 3), and then the collected organic layer was washed well with brine. The remaining water was removed with MgSO₄Drying and filtration, followed by removal of the solvent by vacuum suction, gave the product 2-butyl-cyclopenta-1, 3-diene as a dark brown viscous product in quantitative yield.

2-2 preparation of metallocene compounds

About 4.3g (23mmol) of the ligand compound synthesized in 2-1 was introduced into a dry 250mL Schlenk flask and dissolved in about 60mL of THF. About 11mL of n-BuLi solution (2.0M in hexane, 28mmol) was added thereto, the mixture was stirred overnight, and then the solution was slowly added to a solution containing 3.83g (10.3mmol) of ZrCl dispersed in about 50mL of diethyl ether at-78 deg.C₄(THF)₂In a flask of (1).

After the temperature of the reaction mixture was raised to room temperature, the light brown suspension became a cloudy yellow suspension. After stirring overnight, all solvents were dried, about 200mL of hexane was added for sonication and sedimentation, and then the hexane solution floating on the upper layer was decanted with a cannula and collected. This process was repeated twice to obtain a hexane solution, which was dried by vacuum suction, and it was confirmed that the compound bis (3-butyl-2, 4-dienyl) zirconium (IV) chloride was produced as a pale yellow solid.

¹H NMR(500MHz,CDCl₃):0.91(6H,m),1.33(4H,m),1.53(4H,m),2.63(4H,t),6.01(1H,s),6.02(1H,s),6.10(2H,s),6.28(2H,s)

< preparation example of hybrid Supported metallocene catalyst >

Preparation example 1

2.0kg of toluene and 1000g of silica (Grace Davison, SP2410) were introduced into a 20L SUS high-pressure reactor, and the temperature of the reactor was increased to 40 ℃ while stirring. 5.4kg of methylaluminoxane (10% by weight in toluene, manufactured by Albemarle Company) was introduced into the reactor, the temperature was raised to 70 ℃, and then, the mixture was stirred at about 200rpm for about 12 hours. Thereafter, the temperature of the reactor was lowered to 40 ℃ and the stirring was stopped. Then, the reaction product was left to stand for about 10 minutes, followed by decantation. 2.0kg of toluene was again added to the reaction product, the mixture was stirred for about 10 minutes, the stirring was stopped, and the mixture was allowed to stand for about 30 minutes and then decanted.

2.0kg of toluene was introduced into the reactor, followed by introduction of the compound prepared in Synthesis example 1 (60mmol), the compound prepared in Synthesis example 4(10mmol) and 1000mL of toluene. The temperature of the reactor was raised to 85 ℃ and the reaction mixture was stirred for about 90 minutes.

Thereafter, the reactor was cooled to room temperature, the stirring was stopped, and the reaction product was allowed to stand for about 30 minutes and then decanted. Subsequently, 3kg of hexane was introduced into the reactor, and the hexane slurry solution was transferred to a 20L filter dryer and filtered, and vacuum-dried at 50 ℃ for about 4 hours to obtain 1.5kg of the supported catalyst.

Preparation example 2

A hybrid supported metallocene catalyst was prepared by the same method as in preparation example 1, except that the metallocene compounds of Synthesis examples 2(60mmol) and 4(10mmol) were used.

Preparation example 3

A hybrid supported metallocene catalyst was prepared by the same method as in preparation example 1, except that the metallocene compounds of Synthesis examples 3(60mmol) and 5(10mmol) were used.

Comparative preparation example 1

A hybrid supported metallocene catalyst was prepared by the same method as in preparation example 1, except that only the metallocene compound (70mmol) of synthesis example 1 was used.

Comparative preparation example 2

A hybrid supported metallocene catalyst was prepared by the same method as in preparation example 1, except that the metallocene compounds of Synthesis example 3(60mmol) and comparative Synthesis example 1(10mmol) were used.

Comparative preparation example 3

A hybrid supported metallocene catalyst was prepared by the same method as in preparation example 1, except that the metallocene compounds of Synthesis example 2(60mmol) and comparative Synthesis example 2(10mmol) were used.

The main constituents of the preparations and comparative preparations are described in the following table 1.

[ TABLE 1]

< preparation example of polyolefin >

Ethylene-1-hexene copolymerization

As the polymerization reactor, a 140L continuous polymerization reactor capable of conducting an isobutylene slurry loop process and driven at a reaction flow rate of about 7m/s was prepared. And, reactants required for olefin polymerization described in table 2 were continuously introduced into the reactor.

As the supported catalyst for each olefin polymerization reaction, those prepared in the preparation examples described in table 1 were used, and the supported catalyst was mixed with the isobutylene slurry and introduced.

The olefin polymerization reaction is carried out at a pressure of about 40 bar and a temperature of about 84 ℃.

The main conditions of the polymerization are shown in table 2 below.

[ TABLE 2]

< Experimental example >

For the polyolefins prepared in examples and comparative examples, properties were measured as follows, and the results are shown in table 3 below.

In order to measure the haze and dart impact strength, the obtained polyolefin was treated with an antioxidant (Irganox 1010+ Igafos168, cibaccompany) and then pelletized using a twin-screw extruder (W & P twin-screw extruder, 75phi, L/D ═ 36) at a temperature of 180 to 210 ℃.

(1) Density: measured according to ASTM D1505 standard.

(2) Melt Index (MI)_2.16): measured according to ASTM D1238 (condition E, 190 ℃, 2.16kg load).

(3) Haze: the blow molding is carried out at an extrusion temperature of 130 to 170 ℃ using a single screw extruder (Yoojin Engineering, single screw extruder, blown film M/C, 50phi) until the thickness is 60 μ M. Wherein the die clearance was set to 2.0mm and the blow-up ratio was set to 2.3. The prepared film was measured according to ISO 13468 standard. In this, one sample was measured 10 times and averaged.

(4) Dart impact strength: polymer films were prepared under the same conditions as in (3), and then each film sample was measured 20 times or more according to ASTM D1709[ method A ], and averaged.

(5) SSA thermogram

The polyolefin was first heated to 160 ℃ for 30 minutes using a differential scanning calorimeter (equipment name: DSC8000, manufacturing company: PerkinElmer), thereby eliminating the heat history before measuring the sample.

The temperature was reduced from 160 ℃ to 122 ℃ and held for 20 minutes, the temperature was reduced to 30 ℃ and held for 1 minute, and then increased again. Next, after heating to a temperature 5 ℃ lower than the initial heating temperature of 122 ℃ (117 ℃), the temperature was maintained for 20 minutes, lowered to 30 ℃ and maintained for 1 minute, and then raised again. In this way, while gradually decreasing the heating temperature in the case where the (n +1) th heating temperature is lower by 5 ℃ than the nth heating temperature with the same holding time and cooling temperature unchanged, the above process is repeated until the final heating temperature becomes 52 ℃. Wherein the temperature rise speed and the temperature drop speed are respectively controlled at 20 ℃/min. Finally, the SSA thermogram was measured by observing the change in heat while increasing the temperature from 30 ℃ to 160 ℃ at a temperature increase rate of 10 ℃/min.

(6) Heterogeneity of ethylene sequence (I)

Ethylene sequence heterogeneity (I) was calculated according to the following equation:

[ equation 1]

Heterogeneity of (I) ═ L_w/L_n

In the case of the equation 1, the,

L_wis a weighted average (unit: nm) of the ESL (ethylene sequence length), L_nIs the arithmetic mean (unit: nm) of ESL (ethylene sequence length).

Weighted average L in equation 1_wAnd the arithmetic mean L_nCalculated by the following equations 2 and 3:

[ equation 2]

In the case of the equation 2, the,

[ equation 3]

In the case of the equations 2 and 3,

S_iis the area of each melting peak measured in the SSA thermogram, an

L_iIs the flat corresponding to each melting peak in the SSA thermogramAverage ethylene sequence length (ASL).

Also, ASL was calculated from the SSA thermogram measured above with reference to Journal of Polymer Science Part B: Polymer Physics.2002, vol.40,813-821, and Journal of the Korea Chemical Society 2011, Vol.55, No. 4.

Fig. 1 shows graphs showing the relationship between the unevenness and the dart impact strength of the polyolefins according to examples and comparative examples.

[ TABLE 3]

Referring to table 3 and fig. 1, the polyolefins of examples 1 to 3 of the present invention showed a haze of 11% or less and had significantly excellent dart impact strength, as compared to comparative examples 1 to 3 having the same density.