Olefin-based polymers and methods for making the same

Abstract

The present invention relates to olefin-based polymers and methods for making the same. In particular, according to one embodiment of the present invention, there are provided olefin-based polymers and methods for making the same, the olefin-based polymers having excellent heat sealing properties due to a high proportion of copolymers having many branches and derived from comonomers.

Description

Technical Field

[0001] This invention relates to olefin-based polymers and methods for their preparation. Specifically, this invention relates to olefin-based polymers with excellent heat-sealing properties and methods for their preparation. Background Technology

[0002] Metallocene catalysts have a sandwich structure as their basic form. The metallocene catalyst is one of the catalysts used for olefin polymerization. The metallocene catalyst is a compound in which ligands such as cyclopentadienyl, indenyl, or cycloheptadienyl are coordinated with transition metals or transition metal halide compounds.

[0003] Ziegler-Natta catalysts, another type of catalyst used for olefin polymerization, exhibit non-uniform active sites due to the dispersion of the metal components as active sites on an inert solid surface; however, metallocene catalysts are considered mono-site catalysts with uniform polymerization properties across all active sites because they are compounds with a defined structure. Polymers polymerized using such metallocene catalysts exhibit narrow molecular weight distributions, uniform comonomer distributions, and higher copolymerization activity than Ziegler-Natta catalysts.

[0004] Meanwhile, linear low-density polyethylene (LLDPE) is prepared by copolymerizing ethylene and α-olefins under low pressure using a polymerization catalyst. It has a narrow molecular weight distribution and short chain branches (SCB) of a certain length, and usually does not have long chain branches (LCB). Films made from linear low-density polyethylene have high tensile strength and elongation, as well as excellent tear strength, impact strength, and other general properties of polyethylene. Therefore, it is widely used in stretch films, overlap films, etc., where conventional low-density polyethylene or high-density polyethylene is difficult to apply.

[0005] However, linear low-density polyethylene prepared by metallocene catalysts has poor processability due to its narrow molecular weight distribution, and the films prepared from it often have reduced heat-sealing properties.

[0006] Therefore, there is a need for olefin-based polymers with excellent heat-sealing properties. Summary of the Invention

[0007] Technical issues

[0008] One object of the present invention is to provide olefin-based polymers with excellent heat-sealing properties.

[0009] Another object of the present invention is to provide a method for preparing olefin-based polymers.

[0010] Technical solution

[0011] In one general aspect, an olefin-based polymer is provided having (1) 0.915 g / cm³. 3 Up to 0.950 g / cm 3 (1) density; (2) melt index (I) of 0.5 g / 10 min to 1.5 g / 10 min as measured at 190 °C under a load of 2.16 kg. 2.16 (3) Polydispersity indices (Mw / Mn) of 2 to 6; and (4) satisfying the following relation 1 in temperature rising elution fractionation (TREF) with multimodal distribution:

[0012] [Relation 1]

[0013] C 65 -C 45 >15%

[0014] Where C 45 The percentage by weight of the polymer eluted at 45°C, and C 65 (%) represents the weight of the polymer eluted at 65°C.

[0015] In one specific embodiment of the invention, olefin-based polymers can be prepared by polymerizing olefin-based monomers in the presence of a mixed catalyst comprising: at least one first transition metal compound represented by Chemical Formula 1; and at least one second transition metal compound selected from compounds represented by Chemical Formula 2 and compounds represented by Chemical Formula 3.

[0016] [Chemical Formula 1]

[0017]

[0018] [Chemical Formula 2]

[0019]

[0020] [Chemical Formula 3]

[0021]

[0022] M1 and M2 are different from each other and are independently titanium (Ti), zirconium (Zr), or hafnium (Hf).

[0023] X is a halogen, C is a halogen, and C is a halogen. 1-20 Alkyl, C 2-20 alkenyl, C 2-20 alkynyl group, C 6-20 Aryl, C 1-20 Alkyl C6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 alkylamide group, or C 6-20 aryl amide group, and

[0024] R1 to R 10 Each of the following is independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 alkenyl, substituted or unsubstituted C 6-20 aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 heteroaryl, substituted or unsubstituted C 1-20 Alkylamide group, substituted or unsubstituted C 6-20 Aryl amide group, substituted or unsubstituted C 1-20 Alkyl groups, or substituted or unsubstituted C-16 groups 1-20 Silyl groups, but R1 to R 10 They can independently attach to adjacent groups to form substituted or unsubstituted saturated or unsaturated C2O3. 4-20 ring.

[0025] In a specific embodiment of the present invention, M1 and M2 may be different from each other and may be zirconium or hafnium, respectively, and X may be halogen or C. 1-20 Alkyl groups, and R1 to R 10 They can be hydrogen, substituted or unsubstituted C, independently of each other. 1-20 Alkyl, substituted or unsubstituted C 1-20 alkenyl, or substituted or unsubstituted C 6-20 Aryl.

[0026] In a preferred embodiment of the present invention, M1 can be hafnium, M2 can be zirconium, and X can be chlorine or methyl.

[0027] In a preferred embodiment of the invention, the first transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 1-1 and 1-2, and the second transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 2-1, 2-2, and 3-1:

[0028] [Chemical Formula 1-1][Chemical Formula 1-2]

[0029]

[0030] [Chemical Formula 2-1][Chemical Formula 2-2][Chemical Formula 3-1]

[0031]

[0032] Me stands for methyl group.

[0033] In one specific embodiment of the present invention, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 100:1 to 1:100.

[0034] In one specific embodiment of the invention, the catalyst may comprise at least one co-catalyst selected from the following: a compound represented by chemical formula 4, a compound represented by chemical formula 5, and a compound represented by chemical formula 6:

[0035] [Chemical Formula 4]

[0036]

[0037] [Chemical Formula 5]

[0038]

[0039] [Chemical Formula 6]

[0040] [LH] + [Z(A)4] - Or [L] + [Z(A)4] -

[0041] Where n is an integer of 2 or greater, R a Halogen atoms, C 1-20 Hydrocarbon group, or C substituted with halogen 1-20 hydrocarbon group,

[0042] D is aluminum (Al) or boron (B), R b R c and R d Each is an independent halogen atom, C 1-20 Hydrocarbon groups, halogenated C 1-20 hydrocarbon group, or C 1-20 Alkoxy

[0043] L is a neutral Lewis base or a cationic Lewis base, [LH] + and [L] + Z is a Brønsted acid, Z is a Group 13 element, and A is independently either substituted or unsubstituted C. 6-20 aryl or substituted or unsubstituted C 1-20 alkyl.

[0044] In one specific embodiment of the present invention, the catalyst may further comprise a support for a transition metal compound, a co-catalyst compound, or both.

[0045] In a preferred embodiment of the present invention, the carrier may include at least one selected from silicon dioxide, aluminum oxide and magnesium oxide.

[0046] In this paper, the total amount of mixed transition metal compounds supported on the support can be from 0.001 mmol to 1 mmol based on 1 g of support, and the total amount of cocatalytic compounds supported on the support can be from 2 mmol to 15 mmol based on 1 g of support.

[0047] In one specific embodiment of the invention, the olefin-based polymer can be a copolymer of an olefin-based monomer and an olefin-based comonomer. Specifically, the olefin-based monomer can be ethylene, and the olefin-based comonomer can be at least 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, and 1-hexadecene. Preferably, the olefin-based polymer can be linear low-density polyethylene in which the olefin-based polymer is ethylene and the olefin-based monomer is 1-hexene.

[0048] In another general aspect, a method for preparing an olefin-based polymer includes: polymerizing an olefin-based monomer in the presence of a mixed catalyst to obtain an olefin-based polymer, said mixed catalyst comprising: at least one first transition metal compound represented by chemical formula 1; and at least one second transition metal compound selected from compounds represented by chemical formula 2 and compounds represented by chemical formula 3, wherein the olefin-based polymer has (1) 0.915 g / cm³. 3 Up to 0.950 g / cm 3 (1) density; (2) melt index (I) of 0.5 g / 10 min to 1.5 g / 10 min as measured at 190 °C under a 2.16 kg load. 2.16 (3) Polydispersity indices (Mw / Mn) of 2 to 6; and (4) satisfying the following relation 1 in the multimodal temperature elution fraction (TREF):

[0049] [Relation 1]

[0050] C 65 -C 45 >15%

[0051] Where C 45 The percentage by weight of the polymer eluted at 45°C, and C 65(%) represents the weight of the polymer eluted at 65°C.

[0052] In one specific embodiment of the invention, the polymerization of olefin-based monomers can be carried out by gas-phase polymerization, and specifically, the polymerization of olefin-based monomers can be carried out in a gas-phase fluidized bed reactor.

[0053] Beneficial effects

[0054] An olefin-based polymer according to an exemplary embodiment of the present invention has a high proportion of highly branched copolymers derived from comonomers, and therefore has excellent heat-sealing properties. Attached Figure Description

[0055] Figure 1 This is the temperature rise rinsing stage (TREF) diagram used to describe Relationship 1.

[0056] Figures 2 to 4 The figures are the temperature rinse fractionation (TREF) diagrams for the olefin-based polymers in Examples 1 to 3, respectively.

[0057] Figure 5 and 6 The above are temperature rinse fractionation (TREF) diagrams of the olefin-based polymers of Comparative Examples 1 and 2, respectively. Detailed Implementation

[0058] The invention will be described in more detail below.

[0059] Olefin-based polymers

[0060] According to an exemplary embodiment of the present invention, an olefin-based polymer is provided having (1) 0.915 g / cm³. 3 Up to 0.950 g / cm 3 (1) density; (2) melt index (I) of 0.5 g / 10 min to 1.5 g / 10 min as measured at 190 °C under a 2.16 kg load. 2.16 (3) Polydispersity indices (Mw / Mn) of 2 to 6; and (4) satisfying the following relation 1 in the multimodal temperature elution fraction (TREF):

[0061] [Relation 1]

[0062] C 65 -C 45 >15%

[0063] Where C 45 The percentage by weight of the polymer eluted at 45°C, and C 65 (%) represents the weight of the polymer eluted at 65°C.

[0064] In one specific embodiment of the invention, the density of the olefin-based polymer is 0.915 g / cm³. 3 Up to 0.950 g / cm 3 Preferably, the density of the olefin-based polymer can be 0.915 g / cm³. 3 Up to 0.940 g / cm 3 .

[0065] In one specific embodiment of the invention, the melt index (I0.05) of the olefin-based polymer, as measured at 190°C under a 2.16 kg load, is... 2.16 The melt index can be from 0.5 g / 10 min to 1.5 g / 10 min. Preferably, the melt index of the olefin-based polymer, as measured at 190 °C under a 2.16 kg load, can be from 0.6 g / 10 min to 1.2 g / 10 min.

[0066] In one specific embodiment of the invention, the polydispersity index (Mw / Mn) of the olefin-based polymer can be from 2 to 6. Preferably, the polydispersity index of the olefin-based polymer can be from 4 to 6.

[0067] In a specific embodiment of the present invention, in a multi-peak distribution temperature elution fractionation, the C of the polymer based on olefins in Equation 1 is... 65 -C 45 The value can be greater than 15 (%).

[0068] In a multi-peak TREF curve, the area of ​​the TREF peak between 45°C and 65°C indicates the amount of highly branched copolymer derived from the comonomer, and a high proportion of this indicates a polymer with high heat-sealing properties.

[0069] According to an exemplary embodiment of the present invention, an olefin-based polymer is prepared by polymerizing an olefin-based monomer in the presence of a mixed catalyst comprising: at least one first transition metal compound represented by Chemical Formula 1; and at least one second transition metal compound selected from compounds represented by Chemical Formula 2 and compounds represented by Chemical Formula 3.

[0070] [Chemical Formula 1]

[0071]

[0072] [Chemical Formula 2]

[0073]

[0074] [Chemical Formula 3]

[0075]

[0076] M1 and M2 are different from each other and are independently titanium (Ti), zirconium (Zr), or hafnium (Hf), respectively. Specifically, M1 and M2 can be different from each other and are zirconium or hafnium, and preferably, M1 can be hafnium and M2 can be zirconium.

[0077] X is a halogen, C is a halogen, and C is a halogen. 1-20 Alkyl, C 2-20 alkenyl, C 2-20 alkynyl group, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 alkylamide group, or C 6-20 Aryl amide group, specifically, X can be a halogen or a carbon. 1-20 Alkyl group, and preferably, X can be chloro or methyl, and

[0078] R1 to R 10 Each of the following is independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 alkenyl, substituted or unsubstituted C 6-20 aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 heteroaryl, substituted or unsubstituted C 1-20 Alkylamide group, substituted or unsubstituted C 6-20 Aryl amide group, substituted or unsubstituted C 1-20 Alkyl groups, or substituted or unsubstituted C-16 groups 1-20 Silyl groups, wherein R1 to R 10 They can independently attach to adjacent groups to form substituted or unsubstituted saturated or unsaturated C2O3. 4-20 The ring, and specifically, R1 to R 10 They can be hydrogen, substituted or unsubstituted C, respectively. 1-20 Alkyl, substituted or unsubstituted C 1-20 alkenyl, or substituted or unsubstituted C 6-20 Aryl.

[0079] In a specific embodiment of the present invention, M1 and M2 may be different from each other and may be zirconium or hafnium, respectively, and X may be halogen or C. 1-20Alkyl groups, and R1 to R 10 They can be hydrogen, substituted or unsubstituted C, independently of each other. 1-20 Alkyl, substituted or unsubstituted C 1-20 alkenyl, or substituted or unsubstituted C 6-20 Aryl.

[0080] In a preferred embodiment of the present invention, M1 can be hafnium, M2 can be zirconium, and X can be chlorine or methyl.

[0081] In a preferred embodiment of the present invention, the first transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 1-1 and 1-2, and the second transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 2-1, 2-2, and 3-1:

[0082] [Chemical Formula 1-1][Chemical Formula 1-2]

[0083]

[0084] [Chemical Formula 2-1][Chemical Formula 2-2][Chemical Formula 3-1]

[0085]

[0086] Me stands for methyl group.

[0087] In one specific embodiment of the present invention, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 100:1 to 1:100. Preferably, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 50:1 to 1:50. Preferably, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 10:1 to 1:10.

[0088] In one specific embodiment of the invention, the catalyst may comprise at least one co-catalyst compound selected from the following: a compound represented by chemical formula 4, a compound represented by chemical formula 5, and a compound represented by chemical formula 6:

[0089] [Chemical Formula 4]

[0090]

[0091] Where n is an integer of 2 or greater, R a Halogen atoms, C 1-20 Hydrocarbons, or halogenated C 1-20 Hydrocarbons, and specifically, R a It can be methyl, ethyl, n-butyl, or isobutyl.

[0092] [Chemical Formula 5]

[0093]

[0094] Where D is aluminum (Al) or boron (B), and R b R c and R d Each is an independent halogen atom, C 1-20 Hydrocarbon groups, halogenated C 1-20 hydrocarbon group, or C 1-20 Alkoxy, and specifically, when D is aluminum (Al), R b R c and R d They can be methyl or isobutyl independently of each other, and when D is boron (B), R b R c and R d They can be pentafluorophenyl,

[0095] [Chemical Formula 6]

[0096] [LH] + [Z(A)4] - Or [L] + [Z(A)4] -

[0097] Where L is a neutral Lewis base or a cationic Lewis base, [LH] + and [L] + Z is a Brønsted acid, Z is a Group 13 element, and A is independently either substituted or unsubstituted C. 6-20 aryl or substituted or unsubstituted C 1-20 Alkyl groups, and specifically, [LH] + It can be dimethylaniline Cation, [Z(A)4] - It can be [B(C6F5)4] - , and [L] + It can be [(C6H5)3C] + .

[0098] Specifically, examples of compounds represented by chemical formula 4 include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc., and methylaluminoxane is preferred, but not limited thereto.

[0099] Examples of compounds represented by Formula 5 include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylmethoxide aluminum, dimethylethoxide aluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, etc., with trimethylaluminum, triethylaluminum, and triisobutylaluminum being preferred, but not limited thereto.

[0100] Examples of compounds represented by Formula 6 include triethylammonium tetraphenylborane, tributylammonium tetraphenylborane, trimethylammonium tetraphenylborane, tripropylammonium tetraphenylborane, trimethylammonium tetra(p-tolyl)borane, trimethylammonium tetra(o,p-dimethylphenyl)borane, tributylammonium tetra(p-trifluoromethylphenyl)borane, trimethylammonium tetra(p-trifluoromethylphenyl)borane, tributylammonium tetrapentafluorophenylborane, and N,N-diethylaniline. Tetraphenylborone, N,N-diethylaniline Tetrafluorophenylboron, diethylammonium tetrafluorophenylboron, triphenyl Tetraphenylborone, trimethyl Tetraphenylboron, triethylammonium tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, tripropylammonium tetraphenylaluminum, trimethylammonium tetra(p-tolyl)aluminum, tripropylammonium tetra(p-tolyl)aluminum, triethylammonium tetra(o,p-dimethylphenyl)aluminum, tributylammonium tetra(p-trifluoromethylphenyl)aluminum, trimethylammonium tetra(p-trifluoromethylphenyl)aluminum, tributylammonium tetrapentafluorophenylaluminum, N,N-diethylaniline Tetraphenylaluminum, N,N-diethylaniline Tetrafluorophenylaluminum, diethylammonium tetraphenylaluminum, triphenyl Tetraphenylaluminum, Trimethyl Tetraphenylaluminum, tripropylammonium tetra(p-tolyl)boron, triethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, triphenylcarbon Tetra(p-trifluoromethylphenyl)boron, triphenylcarbon Tetrafluorophenylboron, etc.

[0101] In one specific embodiment of the present invention, the catalyst may further comprise a support for a transition metal compound, a cocatalyst compound, or both. Specifically, the support may support both the transition metal compound and the cocatalyst compound.

[0102] In this document, the support may comprise a material containing hydroxyl groups on its surface, and preferably, a material with highly reactive hydroxyl and siloxane groups that has been dried to remove moisture from its surface can be used. For example, the support may comprise at least one selected from silica, alumina, and magnesium oxide. Specifically, silica, silica-alumina, silica-magnesium oxide, etc., dried at high temperatures can be used as supports, and these typically contain oxide, carbonate, sulfate, and nitrate components, such as Na₂O, K₂CO₃, BaSO₄, and Mg(NO₃)₂. Furthermore, these may include carbon, zeolites, magnesium chloride, etc. However, the support is not limited to these and is not particularly restricted, as long as it can support transition metal compounds and co-catalyst compounds.

[0103] The average particle size of the carrier can be from 10 μm to 250 μm, preferably from 10 μm to 150 μm, and more preferably from 20 μm to 100 μm.

[0104] The micropore volume of the carrier can be from 0.1 cc / g to 10 cc / g, preferably from 0.5 cc / g to 5 cc / g, and more preferably from 1.0 cc / g to 3.0 cc / g.

[0105] The specific surface area of ​​the carrier can be 1m². 2 / g to 1,000m 2 / g, preferably 100m 2 / g to 800m 2 / g, and more preferably 200m 2 / g to 600m 2 / g.

[0106] In a preferred embodiment of the invention, the support may be silica. Herein, the drying temperature of the silica may be from 200°C to 900°C. The drying temperature may be from 300°C to 800°C, and more preferably from 400°C to 700°C. When the drying temperature is below 200°C, the silica contains too much moisture, causing the moisture on the surface to react with the co-catalyst compound; when the drying temperature is above 900°C, the structure of the support may collapse.

[0107] The concentration of hydroxyl groups in the dried silica can be from 0.1 mmol / g to 5 mmol / g, preferably from 0.7 mmol / g to 4 mmol / g, and more preferably from 1.0 mmol / g to 2 mmol / g. When the concentration of hydroxyl groups is less than 0.1 mmol / g, the loading of the first cocatalyst compound decreases, and when the concentration is greater than 5 mmol / g, the catalyst component becomes inactive.

[0108] Based on 1g of support, the total amount of transition metal compounds supported on the support can range from 0.001 mmol to 1 mmol. When the ratio of transition metal compounds to support meets the above range, appropriate supported catalyst activity is observed, which is advantageous in terms of catalyst activity retention and economic feasibility.

[0109] Based on 1g of support, the total amount of cocatalytic compound supported on the support can be from 2mmol to 15mmol. When the ratio of cocatalytic compound to support meets the above range, it is advantageous in terms of maintaining catalyst activity and economic feasibility.

[0110] The support can be one, two, or more. For example, both the transition metal compound and the cocatalyst compound can be supported on one support, or each of the transition metal compound and the cocatalyst compound can be supported on two or more supports. Alternatively, only one of the transition metal compound and the cocatalyst compound can be supported on the support.

[0111] As a method for supporting transition metal compounds and / or co-catalyst compounds in catalysts that can be used for olefin polymerization, physical adsorption or chemisorption can be used.

[0112] For example, physical adsorption methods may include methods that involve contacting a solution in which a transition metal compound is dissolved with a support and then drying it; methods that involve contacting a solution in which a transition metal compound and a cocatalyst compound are dissolved with a support and then drying it; methods that involve contacting a solution in which a transition metal compound is dissolved with a support and then drying it to prepare a support on which a transition metal compound is loaded, contacting a solution in which a cocatalyst compound is dissolved with a support separately and then drying it to prepare a support on which a cocatalyst compound is loaded, and then mixing them; and so on.

[0113] Chemisorption methods can include first loading a cocatalyst compound onto a support surface, and then loading a transition metal compound onto the cocatalyst compound; or methods that covalently bond functional groups on the support surface (e.g., hydroxyl groups (-OH) on the silica surface in the case of silica) to the catalyst compound.

[0114] In one specific embodiment of the invention, the olefin-based polymer can be a homopolymer of an olefin-based monomer or a copolymer of an olefin-based monomer and a comonomer. Preferably, the olefin-based polymer is a copolymer of an olefin-based monomer and an olefin-based comonomer.

[0115] In this paper, olefin-based monomers can be selected from C 2-20 α-olefins, C 1-20 Diene, C 3-20 Cycloolefins and C3-20 At least one of the cyclodienes.

[0116] For example, the olefin-based monomers may be ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, or 1-hexadecene, and the olefin-based polymers may be homopolymers containing only one of the olefin-based monomers exemplified above or copolymers containing two or more of the olefin-based monomers.

[0117] In one exemplary embodiment, the olefin-based polymer can be ethylene and C 3-20 A copolymer of α-olefins. Preferably, the olefin-based polymer can be linear low-density polyethylene in which the olefin-based monomer is ethylene and the olefin-based comonomer is 1-hexene.

[0118] In this case, the ethylene content is preferably from 55% to 99.9% by weight, and more preferably from 90% to 99.9% by weight. The content of the α-olefin-based comonomer is preferably from 0.1% to 45% by weight, and more preferably from 0.1% to 10% by weight.

[0119] Methods for preparing olefin-based polymers

[0120] According to an exemplary embodiment of the present invention, a method for preparing an olefin-based polymer is provided, comprising: polymerizing an olefin-based monomer in the presence of a mixed catalyst to obtain an olefin-based polymer, said mixed catalyst comprising: at least one first transition metal compound represented by the following chemical formula 1; and at least one second transition metal compound selected from compounds represented by the following chemical formula 2 and compounds represented by the following chemical formulas:

[0121] [Chemical Formula 1]

[0122]

[0123] [Chemical Formula 2]

[0124]

[0125] [Chemical Formula 3]

[0126]

[0127] Among them, M1, M2, X and R1 to R 10 As defined above in the project "Olefin-based Polymers".

[0128] As described above, the olefin-based polymer prepared by the preparation method according to an exemplary embodiment of the present invention has (1) 0.915 g / cm³. 3 Up to 0.950 g / cm 3 (1) density; (2) melt index (I) of 0.5 g / 10 min to 1.5 g / 10 min as measured at 190 °C under a 2.16 kg load. 2.16 (3) a polydispersity index (Mw / Mn) of 2 to 5; and (4) satisfying the following relation 1 in the multimodal temperature elution fraction (TREF):

[0129] [Relation 1]

[0130] C 65 -C 45 >15%

[0131] Where C 45 The percentage by weight of the polymer eluted at 45°C, and C 65 (%) represents the weight of the polymer eluted at 65°C.

[0132] In one specific example of the invention, olefin-based polymers can be polymerized by polymerization reactions such as free radical polymerization, cationic polymerization, coordination polymerization, condensation polymerization, and addition polymerization, but are not limited thereto.

[0133] In one exemplary embodiment of the present invention, olefin-based polymers can be prepared by gas-phase polymerization, solution polymerization, slurry polymerization, etc. Preferably, the polymerization of olefin-based monomers can be carried out by gas-phase polymerization, and specifically, the polymerization of olefin-based monomers can be carried out in a gas-phase fluidized bed reactor.

[0134] When preparing olefin-based polymers via solution polymerization or slurry polymerization, examples of solvents to be used may include C 5-12 Aliphatic hydrocarbon solvents, such as pentane, hexane, heptane, nonane, decane and their isomers; aromatic hydrocarbon solvents, such as toluene and benzene; chlorine-substituted hydrocarbon solvents, such as dichloromethane and chlorobenzene; and mixtures thereof, but not limited thereto.

[0135] Invention Embodiments

[0136] Example

[0137] The present invention will be described in more detail below through the following embodiments. However, the following embodiments are merely illustrative and do not limit the scope of the invention.

[0138] Preparation Example

[0139] The transition metal compounds of formula 1-2 (dimethylbis(n-propylcyclopentadienyl)hafnium dichloride) and formula 3-1 ((pentamethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconia dichloride) were purchased from MCN and used without further purification.

[0140] A 10% toluene solution of methylaluminoxane was added to 4.07 g of transition metal compounds of formula 1-2 and 1.68 g of transition metal compounds of formula 3-1, and the solution was stirred at room temperature for 1 hour. The resulting solution was then added to 200 g of silica (XPO-24O2), followed by 1.5 L of toluene, and stirred at 70 °C for 2 hours. The resulting catalyst was washed with 500 mL of toluene and dried under vacuum at 60 °C overnight to obtain 280 g of the supported catalyst in powder form.

[0141] Examples 1 to 3

[0142] Ethylene / 1-hexene copolymers were prepared separately using a gas-phase fluidized bed reactor in the presence of the supported catalyst obtained in the preparation example. The ethylene partial pressure in the reactor was maintained at approximately 15 kg / cm³. 2 And maintain the polymerization temperature between 70°C and 90°C.

[0143] The polymerization conditions of the embodiments are shown in Table 1 below.

[0144] [Table 1]

[0145] Example 1 Example 2 Example 3 Polymerization temperature (°C) 74.8 80.4 83.6 Catalyst injection rate (g / hour) 1.97 1.31 1.35 Hydrogen injection rate (g / hour) 2.28 2.13 2.15 1-Hexene injection rate (kg / hour) 1.53 1.54 1.77 Hydrogen / ethylene concentration (%) ratio 0.045 0.049 0.047 1-Hexene / Ethylene Concentration (%) Ratio 1.45 1.39 1.44 Production per hour (kg / hour) 6.91 6.22 6.52

[0146] Comparison of Examples 1 and 2

[0147] For comparison, linear low-density polyethylene, namely M1810HN (Comparative Example 1) and M2010EN (Comparative Example 2), which are available from Hanwha Solutions, were used.

[0148] Test case

[0149] The physical properties of the olefin-based polymers of the above embodiments were measured using the following methods and standards. The results are shown in Table 2.

[0150] (1) Density

[0151] Measured according to ASTM D1505.

[0152] (2) Melt Flow Index and Melt Flow Rate (MFR)

[0153] According to ASTM D 1238, the melt flow index was measured at 190°C under loads of 21.6 kg and 2.16 kg, and the ratio (MI) was calculated. 21.6 / MI 2.16 ).

[0154] (3) Polydispersion index

[0155] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) were measured by gel permeation chromatography (GPC), and the polydispersity index was determined by the ratio.

[0156] (4) TREF

[0157] The TREF plot shows the difference between the weight % values ​​at 65°C and at 45°C, which is a temperature-dependent cumulative weight percentage of elution (total weight %) using a cross-fractional chromatography (CFC) apparatus.

[0158] [Table 2]

[0159] unit Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 <![CDATA[MI 2.1 6]]> g / 10 minutes 1.11 0.87 0.99 1.02 1.04 <![CDATA[MI 21.16 ]]> g / 10 minutes 27.8 18.4 20.8 16.23 33.25 MFR - 25 21.2 21.0 15.9 35.9 density <![CDATA[g / cm 3 ]]> 0.9210 0.9174 0.9197 0.9179 0.9186 polydispersity index - 4.65 4.74 5.29 4.1 5.7 <![CDATA[C 65 -C 45 ]]> ％ 17.69 15.19 19.64 9.28 9.30

[0160] Industrial applicability

[0161] As shown in Table 2 and Figures 1 to 3 Indeed, since the olefin-based polymers according to specific examples of the present invention are highly branched copolymers derived from comonomers, they have excellent heat-sealing properties.

Claims

1. An olefin-based polymer having (1) a density from 0.915 g / cm 3 to 0.950 g / cm 3 ; (2) a melt index, as measured at 190 °C under a 2.16 kg load, from 0.5 g / 10 min to 1.5 g / 10 min; and (3) a polydispersity index M w / M n from 2 to 6; and (4) satisfies the following relationship 1 in a temperature rising elution fractionation of a multimodal distribution, 0.5 < Mz / Mw < 2.5 (1) wherein the olefin-based polymer is prepared by copolymerizing an olefin-based monomer and an olefin-based comonomer in the presence of a mixed catalyst comprising: a first transition metal compound that is at least one of transition metal compounds represented by the following Chemical Formulas 1-1 and 1-2; and a second transition metal compound represented by the following Chemical Formula 3-1, wherein the olefin-based monomer is ethylene and the olefin-based comonomer is 1-hexene: [Relationship Formula 1] C 65 -C 45 >15% where C 45 is the weight percent of polymer eluted at 45°C, and C 65 is the weight percent of polymer eluted at 65°C, [Chemical Formula 1-1][Chemical Formula 1-2] wherein Me is a methyl group, [Chemical Formula 3-1] 2. The olefin-based polymer of claim 1, wherein the olefin-based polymer has (1) a density from 0.915 g / cm 3 to 0.940 g / cm 3 ; (2) a melt index, as measured at 190 °C under a 2.16 kg load, from 0.5 g / 10 min to 1.5 g / 10 min; and (3) a polydispersity index from 4 to 6.

3. The olefin-based polymer of claim 1, wherein a molar ratio of the first transition metal compound to the second transition metal compound is in a range of 100:1 to 1:

100.

4. The olefin-based polymer of claim 1, wherein the catalyst comprises at least one cocatalyst compound selected from the group consisting of methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, a compound represented by the following Chemical Formula 5, and a compound represented by the following Chemical Formula 6: [Chemical Formula 5] [Chemical Formula 6] [L-H] + [Z(A)4] - or [L] + [Z(A)4] - wherein D is aluminum or boron, R b , R c , and R d are each independently a halogen atom, a C 1-20 hydrocarbon group, a halogen-substituted C 1-20 hydrocarbon group, or a C 1-20 alkoxy group, L is a neutral Lewis base or a cationic Lewis base, [L-H] + and [L] + is a Bronsted acid, Z is a group 13 element, and A is independently of the other C 6-20 aryl or C 1-20 alkyl.

5. The olefin-based polymer of claim 4, wherein the catalyst further comprises a support on which the transition metal compound, the cocatalyst compound, or both are supported.

6. The olefin-based polymer of claim 5, wherein the support includes at least one selected from the group consisting of silicon dioxide, aluminum oxide, and magnesium oxide.

7. The olefin-based polymer of claim 5, wherein a total amount of the mixed transition metal compound supported on the support is 0.001 mmol to 1 mmol based on 1 g of the support, and a total amount of the cocatalyst compound supported on the support is 2 mmol to 15 mmol based on 1 g of the support.

8. The olefin-based polymer of claim 1, wherein the olefin-based polymer is a linear low density polyethylene in which the olefin-based monomer is ethylene and the olefin-based comonomer is 1-hexene.

9. A process for the preparation of an olefin-based polymer, the process comprising: polymerizing an olefin-based monomer and an olefin-based comonomer in the presence of a mixed catalyst comprising: a first transition metal compound that is at least one of transition metal compounds represented by the following Chemical Formulas 1-1 and 1-2; and a second transition metal compound represented by the following Chemical Formula 3-1, wherein the olefin-based monomer is ethylene and the olefin-based comonomer is 1-hexene, wherein the olefin-based polymer has (1) a density from 0.915 g / cm 3 to 0.950 g / cm 3 ; (2) a melt index, as measured at 190 °C under a 2.16 kg load, from 0.5 g / 10 min to 1.5 g / 10 min; and (3) a polydispersity index M w / M n from 2 to 6; and (4) satisfies the following relationship 1 in a temperature rising elution fractionation of the multimodal distribution: [Relationship Formula 1] C 65 -C 45 >15% where C 45 is the weight percent of polymer eluted at 45°C, and C 65 is the weight percent of polymer eluted at 65°C, [Chemical Formula 1-1][Chemical Formula 1-2] wherein Me is a methyl group, [Chemical Formula 3-1] 10. The method for preparing an olefin-based polymer of claim 9, wherein the polymerization of the olefin-based monomer is performed by gas phase polymerization.

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