High density vinyl polymers using hybrid supported catalysts and methods of making same

Abstract

The present invention relates to a high-density vinyl polymer exhibiting high processability by using a mixed catalyst composition and a method for preparing the same, and provides a high-density polyvinyl polymer having excellent optical properties, excellent mechanical properties such as impact resistance and hardness, and excellent stretchability. The high density vinyl polymer of the present invention provides a polyvinyl polymer capable of biaxially stretching or simultaneous stretching.

Description

Technical Field

[0001] This invention provides a high-density vinyl polymer exhibiting high processability through the use of a mixed catalyst composition and a method for preparing the same. Background Technology

[0002] Polyethylene (PE) is a polymer used in a wide variety of containers, such as shopping bags, vinyl houses, fishing nets, cigarette paper, noodle bags, battery boxes, car bumpers, as well as internal materials, packaging films, fibers, pipes, packaging materials, and paints. The mechanical and thermal properties of PE are affected by its molecular weight and density, thus its applications vary. Generally, lower density PE polymers offer better transparency and impact strength, but physical properties such as heat resistance, hardness, and flexural modulus deteriorate, as does chemical resistance. Conversely, higher density PE polymers offer better physical properties such as heat resistance, hardness, and flexural modulus, and higher chemical resistance, but lower transparency and impact strength.

[0003] Meanwhile, low-density polyethylene (LDPE) possesses excellent tensile properties, making it primarily used as a packaging material. However, its mechanical properties, such as flexural modulus, are relatively low, thus limiting its use as a standalone packaging material. Furthermore, high-density polyethylene (HDPE), while meeting these mechanical properties, lacks tensile strength, making it unsuitable for manufacturing packaging films. Therefore, the current primary method for using polyethylene as packaging material is multilayer packaging materials, obtained by laminating LPE film with PET (polyethylene terephthalate) or PA (polyamide). Because these multilayer packaging materials are not made from a single material but rather are laminates containing PET or PA, they are difficult to recycle, resulting in significant environmental pollution.

[0004] Therefore, there is a need to develop technologies to provide new high-density polyethylene (HDPE) that can be processed into single-component packaging materials for use therein. Furthermore, despite the use of HDPE, there is still a need for polyethylene resins that possess excellent tensile strength while meeting sufficient mechanical properties. In other words, there is a need to investigate the preparation of HDPE that can be processed into food packaging materials and used therein as a new single material with sufficient ductility and excellent impact strength and chemical resistance.

[0005] There is a need to develop high-density polyethylene (HDPE) and its preparation methods to address the aforementioned issues. In other words, to prepare HDPE for the production of single-use packaging materials, research is needed on HDPE and its preparation methods that simultaneously achieve excellent mechanical properties, excellent chemical resistance, high tensile strength, and excellent molding processability using metallocene catalysts. Summary of the Invention

[0006] Technical issues The present invention provides high-density polyethylene, which can be used in packaging films and has excellent optical and mechanical properties, such as impact resistance and hardness, as well as excellent tensile strength as a single polyethylene resin.

[0007] Solution to the problem This invention provides a method for preparing high-density polyethylene, the method comprising: reacting ethylene with C4-C4 in the presence of a mixed metallocene catalyst. 20 α-olefin polymerization, wherein the mixed metallocene catalyst comprises transition metal compounds of formulas 1 to 3, wherein the mixed metallocene catalyst comprises transition metal compounds in a molar ratio of formula 1: formula 2: formula 3 = 1:0.2~3:1~7: [Formula 1]

[0008] [Equation 2]

[0009] [Formula 3]

[0010] (In Equations 1 to 3, R) a It is a C2-C6 alkylene group, R b and R c Each of R1, R2, R3, R4, and R5 is independently a C1-C6 alkylene group; R1, R2, R3, R4, and R5 are independently C1-C5 alkyl groups; X is a halogen; m, m1, and m2 are integers from 0 to 4; n is an integer from 0 to 3; and o is an integer from 1 to 4. In one aspect of the invention, C4-C 20 The α-olefin can be a C5-C8 α-olefin, and specifically, it can be 1-hexene.

[0011] In one aspect of the invention, the mixed metallocene catalyst may be a supported catalyst in which a transition metal compound and a co-catalyst are supported on a support.

[0012] In one aspect of the invention, the co-catalyst is at least one selected from the group consisting of compounds represented by formulas 7 to 9 below: [Formula 7]

[0013] [Formula 8]

[0014] [Formula 9] [LH] + [Z(A)4] - Or [L] + [Z(A)4]- (In Equations 7 to 9, n is an integer greater than or equal to 2, and R6 is a halogen, C1-C 20 Alkyl or halogen-substituted C1-C 20 Alkyl group, D is aluminum (Al) or boron (B), R7, R8 and R9 are each independently halogen, C1-C 20 Straight-chain or branched alkyl groups, halogen-substituted C1-C 20 Alkyl or C1-C 20 Alkyl groups, L is a neutral or cationic Lewis base, [LH] + and [L] + It is a Brønsted acid, Z is a group 13 element, and A is C6-C. 20 Aryl or C1-C 20 alkyl.) In one aspect of the invention, the carrier may be at least one selected from the group consisting of silicon dioxide, aluminum oxide and magnesium oxide.

[0015] This invention provides a method for reacting ethylene with C4-C in the presence of a mixed catalyst. 20 High-density polyethylene resin prepared by α-olefin polymerization, wherein the high-density polyethylene resin has a density of 0.94 g / cm³. 3 Or higher density, 25 or higher PDI, and capable of stretching 4 times or more in the machine direction (MD) at 200% / s at 120°C to 130°C, followed by sequential biaxial stretching 4 times or more in the transverse direction (TD), or capable of simultaneously biaxial stretching 4×4 times or more in both the machine direction (MD) and transverse direction (TD).

[0016] In one aspect of the invention, Formula 1 can be a transition metal compound represented by Formula 4: [Formula 4] .

[0017] In one aspect of the invention, Formula 2 can be a transition metal compound represented by Formula 5: [Formula 5] .

[0018] In one aspect of the invention, Formula 3 can be a transition metal compound represented by Formula 6: [Formula 6] .

[0019] In one aspect of the invention, the high-density polyethylene resin may have a melt flow rate (MFR) of 40 or higher.

[0020] In one aspect of the invention, the high-density polyethylene resin may have a crystallinity of 80% or lower (Xc).

[0021] The present invention provides a high-density polyethylene film comprising the above-mentioned high-density polyethylene resin.

[0022] In one aspect of the invention, the high-density polyethylene film may have a haze of 25% or less as measured according to ASTM D1003.

[0023] In one aspect of the invention, the high-density polyethylene film may have a transparency of 70% or higher as measured according to ASTM D1003.

[0024] In one aspect of the invention, the high-density polyethylene film may have an impact strength of 120 gf or higher as measured according to ASTM D1709.

[0025] Advantages of the present invention The present invention provides a high-density polyethylene-based polymer capable of high-multiplication biaxial stretching or simultaneous biaxial stretching using a mixed metallocene catalyst, and a method thereof for preparation thereof.

[0026] The present invention provides a high-density polyethylene-based polymer and a method for preparing the same, the high-density polyethylene-based polymer having excellent optical properties, excellent mechanical properties (such as impact resistance and hardness) and excellent processability.

[0027] The present invention provides a high-density polyethylene-based polymer using a mixed metallocene catalyst and a method for preparing the same, wherein the high-density polyethylene-based polymer can be biaxially stretched at a high ratio or simultaneously biaxially stretched, for example, it can be stretched at least 4 times simultaneously and sequentially in the MD and TD directions. Detailed Implementation

[0028] Unless otherwise specified in this specification, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this description is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0029] Unless the context clearly specifies otherwise, the singular form used in the specification is intended to cover the plural form as well.

[0030] The expressions “comprising,” “including,” “containing,” “having,” and “characterizing” used in this specification are open-ended descriptions with equivalent meanings and do not exclude additional elements, materials, or processes not listed.

[0031] Unless otherwise specified, the % units used in this specification refer to weight.

[0032] The invention will now be described in detail. However, this is merely exemplary, and the invention is not limited to the specific embodiments described by way of example.

[0033] Polyethylene polymers are used in packaging materials across various industries. When used in packaging, low-density polyethylene (LDPE) is often used in conjunction with other resin films due to its excellent processability and tensile strength. However, LDPE has poor mechanical properties and is therefore often used as a laminating material with resin films such as polyethylene terephthalate (PET) or polyamide (PA). In this case, it is used as a laminating material for different materials, but it cannot be recycled, leading to numerous environmental problems and limiting its use.

[0034] To address these issues, attempts have been made to apply high-density polyethylene (HDPE), with its excellent mechanical properties, to packaging materials. However, while mechanical strength and chemical resistance increase in this case, transparency and tensile properties deteriorate, resulting in insufficient film tensile strength. Therefore, its use as a single packaging material remains problematic.

[0035] To overcome this, various high-density polyethylene polymers have been developed using metallocene catalysts, but it is still not possible to prepare high-density polyethylene with sufficient heat resistance, hardness, flexural modulus and chemical resistance while also satisfying transparency and biaxial tensile properties.

[0036] To address the aforementioned problems, this invention provides packaging materials that possess mechanical strength and tensile properties, and can be prepared using specific mixed metallocene catalysts. For example, high-density polyethylene capable of sequential biaxial stretching and simultaneous biaxial stretching at high ratios, and methods for preparing the same, thus completing the present invention.

[0037] This invention provides a method for preparing high-density polyethylene for packaging materials, the high-density polyethylene having a density of 0.94 g / cm³. 3 Or higher density and excellent ductility and mechanical properties, this method involves reacting ethylene with C4-C in the presence of a mixed metallocene catalyst. 20 The polymerization of α-olefins is carried out using a mixed metallocene catalyst comprising compounds of formulas 1 to 3: [Formula 1]

[0038] [Equation 2]

[0039] [Formula 3]

[0040] (In Equations 1 to 3, R) a It is a C2-C6 alkylene group, R b and Rc Each of R1, R2, R3, R4, and R5 is independently a C1-C6 alkylene group; R1, R2, R3, R4, and R5 are independently C1-C5 alkyl groups; X is a halogen; m, m1, and m2 are integers from 0 to 4; n is an integer from 0 to 3; and o is an integer from 1 to 4. For example, mixed metallocene catalysts may include compounds of formula 1: formula 2: formula 3 in a molar ratio of 1:0.2 to 3:1 to 7, preferably 1:0.2 to 1.5:1 to 6, but the molar ratio is not limited thereto. When these compounds are included, they can exhibit advantageous physical properties when used in polyethylene packaging materials.

[0041] For example, for the ratios of Equations 1 to 3, the molar ratio of Equation 2 to Equation 1 can be 1:0.2 to 3, and the molar ratio of Equation 3 to Equation 1 can be 1:1 to 7.

[0042] In the method for preparing high-density polyethylene according to the present invention, transparent high-density polyethylene with high processability and high mechanical properties (such as sufficient heat resistance, impact strength and hardness) can be prepared, thus providing the effect of providing a method for preparing high-density polyethylene suitable for packaging materials.

[0043] Specifically, when preparing polyethylene using conventional metallocene catalysts, the problem is that when mechanical properties such as heat resistance, impact strength, and hardness are met, the biaxial tensile properties are poor; while when high processability is met due to high tensile properties, the mechanical properties are poor.

[0044] However, using the mixed metallocene of ethylene and C4-C according to the present invention with the above-described compositional ratio 20 High-density polyethylene prepared from α-olefins meets the requirements for mechanical properties and biaxial tensile characteristics.

[0045] Furthermore, the hybrid metallocene catalyst according to the present invention has excellent activity, enabling stable operation in the preparation of high-density polyethylene, thus providing the process advantage of continuous preparation of high-density polyethylene.

[0046] As an example, in mixed metallocene catalysts, the transition metal compound of Formula 1 can be a transition metal compound of Formula 4: [Formula 4]

[0047] The transition metal compound of Formula 4 exhibits very high catalytic activity, and the polyethylene prepared from it is characterized by high biaxial tensile properties.

[0048] As an example, in a mixed metallocene catalyst, the transition metal compound of Formula 2 can be a transition metal compound of Formula 5: [Formula 5]

[0049] The transition metal compounds of Formula 5 can exhibit high comonomer introduction during polymer preparation.

[0050] As an example, in mixed metallocene catalysts, the transition metal compound of Formula 3 can be a transition metal compound of Formula 6: [Formula 6]

[0051] The transition metal compounds of Formula 6 can exhibit high comonomer introduction, can form high molecular weight polymers during polymer preparation, and can improve high mechanical properties, such as impact strength and flexural strength.

[0052] In embodiments, when the mixed metallocene catalyst of the present invention comprises transition metal compounds of formulas 4 to 6, the polyethylene polymer prepared from the metallocene catalyst exhibits mechanical strength and biaxial tensile properties, which is more advantageous for use in the substrate layer included in multilayer packaging materials, and is therefore more preferred.

[0053] In the embodiments, the mixed metallocene catalyst can be a supported catalyst in which a transition metal compound and a co-catalyst are supported on a support.

[0054] Co-catalysts may include compounds of formulas 7 to 9: [Formula 7]

[0055] [Formula 8]

[0056] [Formula 9] [LH] + [Z(A)4] - Or [L] + [Z(A)4] - (In Equations 7 to 9, n is an integer greater than or equal to 2, and R6 is a halogen, C1-C 20 Alkyl or halogen-substituted C1-C 20 Alkyl group, D is aluminum (Al) or boron (B), R7, R8 and R9 are each independently halogen, C1-C 20 Straight-chain or branched alkyl groups, halogen-substituted C1-C 20 Alkyl or C1-C 20 Alkyl groups, L is a neutral or cationic Lewis base, [LH] + and [L] +It is a Brønsted acid, Z is a group 13 element, and A is C6-C. 20 Aryl or C1-C 20 alkyl.) The compound represented by Formula 7 may be at least one selected from the group consisting of methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, and butylaluminoxane, but is not limited thereto.

[0057] The compound represented by Formula 8 may be, for example, at least one selected from the group consisting of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-sec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylmethoxide aluminum, dimethylethoxide aluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, and tributylboron, but is not limited thereto.

[0058] The compound represented by Formula 9 may, for example, be at least one selected from the group consisting of: 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 tetra(pentafluorophenyl)borane, N,N-diethylphenylammonium tetraphenylborane, N,N-diethylphenylammonium tetra(pentafluorophenyl)borane, diethylammonium tetra(pentafluorophenyl)borane, triphenylphosphonium tetraphenylborane, trimethylphosphonium tetraphenylborane, triethylammonium tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, tripropylammonium tetraphenylaluminum, trimethylammonium tetra(p-tolyl)aluminum, triethylammonium tetra(p-tolyl)aluminum, triethylammonium tetraphenyl ...phenylaluminum, triethylammonium tetra(p-tolyl)aluminum, triethylammonium tetraphenylaluminum, Propylammonium tetra(p-tolyl)aluminum, triethylammonium tetra(o,p-dimethylphenyl)aluminum, tributylammonium tetra(p-trifluoromethylphenyl)aluminum, trimethylammonium tetra(p-trifluoromethylphenyl)aluminum, tributylammonium tetra(pentafluorophenyl)aluminum, N,N-diethylphenylammonium tetraphenylaluminum, N,N-diethylphenylammonium tetra(pentafluorophenyl)aluminum, diethylammonium tetra(pentafluorotetraphenyl)aluminum, triphenylphosphonium tetraphenylaluminum, trimethylphosphonium tetraphenylaluminum, tripropylammonium tetra(p-tolyl)boron, triethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, triphenylcarbamonium tetra(p-trifluoromethylphenyl)boron, and triphenylcarbamonium tetra(pentafluorophenyl)boron, but not limited to these.

[0059] The carrier may be at least one selected from the group consisting of silicon dioxide, aluminum oxide and magnesium oxide, but is not limited thereto.

[0060] Based on 1 g of support, the mixed metallocene catalyst may include 0.001 mmol to 10 mmol or 0.001 mmol to 1 mmol of three transition metal compounds of formulas 1 to 3, and based on 1 g of support, may include 1 mmol to 20 mmol or 2 mmol to 15 mmol of co-catalyst, but the invention is not necessarily limited thereto.

[0061] In the embodiments, the average particle size of the carrier may be, but is not limited to, 10 μm to 250 μm, 10 μm to 150 μm, or 20 μm to 100 μm.

[0062] The micropore volume of the carrier can be, but is not limited to, 0.1 ml / g to 10 ml / g, 0.5 ml / g to 5 ml / g, or 1.0 ml / g to 3.0 ml / g.

[0063] In the embodiments, the mixed metallocene catalyst may be injected into the reactor at a rate of 0.1 g / h or higher, 0.5 g / h or higher, 10 g / h or lower, or 5 g / h or lower, for example, 0.1 g / h to 10 g / h or 0.5 g / h to 5 g / h, but the invention is not limited thereto.

[0064] In an embodiment, high-density polyethylene can be prepared by injecting hydrogen gas together with the monomer into a reactor. In an embodiment, hydrogen gas can be injected into the reactor at a rate of 0.1 g / h or higher, 1 g / h or higher, 5 g / h or lower, 100 g / h or lower, or 50 g / h or lower, for example, from 0.1 g / h to 100 g / h or from 1 g / h to 50 g / h, but the invention is not limited thereto.

[0065] In the embodiment, C4-C 20 α-olefins can be C4-C 12 α-olefins, more specifically, C4-C 20 α-Alkenes can be at least one selected from the group consisting of 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-itocene, 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene, and 3,4-dimethyl-1-hexene. As a specific example, C4-C 20 α-Alkenes can be 1-hexene, but are not necessarily limited to this.

[0066] In one embodiment, C4-C 20α-Olefins may be injected into the reactor at rates of 50 g / h or higher, 100 g / h or higher, 150 g / h or higher, 1500 g / h or lower, or 1000 g / h or lower, for example, from 50 g / h to 1500 g / h or from 100 g / h to 1000 g / h, but are not limited thereto.

[0067] In the embodiments, the hydrogen / ethylene molar ratio may be 0.01 or higher, 0.1 or higher, 10 or lower, or 5 or lower, for example, 0.01 to 10, 0.1 to 5, but is not limited thereto.

[0068] In the embodiments, the hexene / ethylene molar ratio may be 0.01 or higher, 0.1 or higher, 10 or lower, or 5 or lower, for example, 0.01 to 10, 0.1 to 5 or any value in between, but is not limited thereto.

[0069] In the examples, ethylene and C4-C 20 The polymerization of α-olefins can be carried out at temperatures of 50°C to 200°C, 60°C to 100°C, or 60°C to 90°C and pressures of 1 bar to 50 bar, 1 bar to 30 bar, or any of the above values ​​and any values ​​in between, but is not limited thereto, and it should be understood that the polymerization temperature and pressure can be appropriately varied depending on the reactants and reaction conditions.

[0070] In the examples, ethylene and C4-C 20 The polymerization of α-olefins can be a slurry-phase polymerization or a gas-phase polymerization, and when polymerization is carried out in a liquid or slurry phase, a solvent may be further included. Specifically, examples of solvents may include propane, butane, pentane, hexane, octane, decane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, dichloromethane, chloroethane, dichloroethane, and chlorobenzene, and these solvents may be mixed and used in certain proportions, but the invention is not limited thereto.

[0071] This invention provides a method for reacting ethylene and C4-C in the presence of a mixed catalyst. 20 High-density polyethylene resin prepared by α-olefin polymerization, wherein the high-density polyethylene resin has a density of 0.94 g / cm3 or higher, a PDI of 25 or higher, and is capable of being stretched 4 times or more in the machine direction (MD) at 200% / s at 120 to 130°C, followed by sequential biaxial stretching 4 times or more in the transverse direction (TD), or simultaneously biaxially stretched 4×4 times or more in both the machine direction (MD) and the transverse direction (TD). Furthermore, the high-density polyethylene according to the invention can provide, under the above conditions, a high-density polyethylene resin capable of being simultaneously biaxially stretched four times or more in both the sequential stretching and the simultaneous biaxial stretching along the MD×TD direction.

[0072] In this embodiment, the density of the high-density polyethylene resin can be 0.94 g / cm³. 3 or higher, 0.96 g / cm 3 Or higher, 0.99 g / cm 3 Or lower, 0.97 g / cm³ 3 Or lower, or 0.96 g / cm³ 3 Or even lower, for example, 0.94 g / cm³ 3 Up to 0.99 g / cm 3 0.94 g / cm 3 Up to 0.96 g / cm 3 , or any of the above values ​​and any values ​​in between.

[0073] Its PDI can be 30 or higher, 40 or higher, 50 or higher, 60 or higher, 70 or lower, 60 or lower, 50 or lower, 55 or lower, 50 or lower, 40 or lower, such as 30 to 70, 30 to 60, or any of the above values ​​and any value in between.

[0074] For example, high-density polyethylene resin may have a weight-average molecular weight of 50,000 g / mol to 20,000 g / mol, 70,000 g / mol to or 90,000 g / mol to 15,000 g / mol, and a number-average molecular weight of 2,000 g / mol to 10,000 g / mol, 3,000 g / mol to 7,000 g / mol, or 3,000 g / mol to 5,000 g / mol.

[0075] As another example, high-density polyethylene resin may have a Z weight-average molecular weight of 200,000 g / mol to 500,000 g / mol, 250,000 g / mol to 500,000 g / mol, or 300,000 g / mol to 500,000 g / mol.

[0076] The high-density polyethylene resin according to the invention can be stretched 4 times or more, 5 times or more, 7 times or more, or 20 times in the machine direction (MD), for example 4 to 20 times, 5 to 15 times, or any of the above values ​​and any values ​​in between.

[0077] In addition, high-density polyethylene resin can be stretched in the machine direction (MD) and then stretched in the transverse direction (TD) by 4 times or more, 7 times or more, 9 times or more, or 20 times or less, for example, 4 to 20 times, 7 to 15 times, or any of the above values ​​and any values ​​in between.

[0078] In the embodiments, as described above, the high-density polyethylene of the present invention can not only undergo sequential biaxial stretching along the MD direction and then along the TD direction, but also simultaneous biaxial stretching. Specifically, the high-density polyethylene resin of the present invention can be simultaneously stretched at 120 to 130°C at a speed of 200% / s along the machine direction (MD) and transverse direction (TD) by 4 times or more, 5 times or more, 9 times or more, 15 times or more, or 20 times or less, for example, 4 to 20 times, or any of the above values ​​and any values ​​in between. Specifically, the fact that the high-density polyethylene resin of the present invention can be stretched within the above range can be considered a significant feature distinguishing it from conventional high-density polyethylene resins.

[0079] Specifically, conventional high-density polyolefin resins prepared using metallocene catalysts tend to fracture or tear during biaxial stretching. However, the high-density polyethylene resin according to the present invention can be sequentially and simultaneously biaxially stretched at the aforementioned multiples and exhibits superior processability and tensile strength compared to conventional high-density polyethylene. Therefore, when applied to polyethylene-based packaging materials, it has the effect of being usable as a single polyethylene packaging material.

[0080] In other words, the high-density polyethylene resin according to the present invention can solve the problem that conventional polyethylene-based packaging materials cannot achieve high mechanical and tensile properties, and therefore cannot be used to manufacture packaging materials made from a single polyethylene component. Therefore, the high-density polyethylene resin according to the present invention has excellent mechanical properties and can easily manufacture packaging materials using a single material, thereby replacing layered packaging materials containing conventional resins and using non-recyclable low-density polyethylene.

[0081] Therefore, the high-density polyethylene resin according to the present invention can be applied to polyethylene packaging materials to provide recyclable packaging materials, thereby having significant economic and environmental benefits.

[0082] In embodiments, the high-density polyethylene resin according to the invention may have a melt flow ratio (MFR) of 40 or higher, 50 or higher, 60 or higher, 70 or higher, 100 or lower, or 80 or lower, for example 60 to 100, 60 to 90, 60 to 80, or any of the above values ​​and any values ​​in between (MI (21.6 kg) / MI (2.16 kg)), as measured and calculated according to ASTM D 1238 at 190°C under loads of 21.6 kg and 2.16 kg respectively.

[0083] In embodiments, the high-density polyethylene resin according to the invention may have a crystallinity (Xc) of 80% or less, 70% or more, 30% or more, 40% or more, or 50% or more, for example, 30% to 80%, 40% to 70%, or any of the above values ​​and any values ​​in between, as measured using a differential scanning calorimeter (DSC, device name: DSC 2920, manufacturer: TAinstrument).

[0084] In other words, since the high-density polyethylene resin according to the present invention satisfies the above-mentioned values ​​of density, PDI, MFR and crystallinity (Xc), it exhibits high optical and tensile properties, and therefore, despite being high-density polyethylene, it still has the effect of being used as a packaging material and a single resin product.

[0085] Although this article is not limited to explanation, it can be interpreted that high-density polyethylene has high hardness, chemical resistance, transparency and biaxial tensile properties by having a high PDI value, low crystallinity and high MFR while simultaneously meeting the above density range.

[0086] The present invention provides a high-density polyethylene film comprising the above-described high-density polyethylene resin.

[0087] Since the high-density polyethylene film of the present invention includes the above-mentioned high-density polyethylene resin, it can be used in products that require high mechanical properties and tensile properties in addition to high density, high PDI, low crystallinity, high MFR and biaxial tensile properties, and in particular, it can be applied to the above-mentioned polyethylene packaging materials to manufacture polyethylene single packaging materials.

[0088] The high-density polyethylene film of the present invention can be manufactured by extruding and stretching the high-density polyethylene resin or by blowing the polyethylene resin, but the manufacturing method is not limited to these, as long as the high-density polyethylene resin can form a film.

[0089] In the embodiments, the high-density polyethylene film may have a haze of 25% or less, 24% or less, 23% or less, 20% or less, 15% or less, 1% or more, 5% or more, or 10% or more, as measured according to ASTM D1003, for example, 1% to 25%, 5% to 25%, or any of the above values ​​and any values ​​in between.

[0090] In an embodiment, the high-density polyethylene film may have a transparency of 50% or higher, 60% or higher, 70% or higher, 99% or lower, 90% or lower, or 85% or lower, as measured according to ASTM D1003, for example 50% to 99%, more particularly 60% to 99%, or any of the above values ​​and any values ​​in between.

[0091] In addition, high-density polyethylene films may have an impact strength of 100 gf or higher, 110 gf or higher, 120 gf or higher, 150 gf or higher, 200 gf or higher, 250 gf or higher, 300 gf or higher, 350 gf or higher, 390 gf or higher, 400 gf or higher, 430 gf or higher, 600 gf or lower, 500 gf or lower, or 450 gf or lower, for example, 120 gf to 600 gf, 250 gf to 500 gf, or any of the above values ​​and any values ​​in between, as measured according to ASTM D1709.

[0092] Since the high-density polyethylene film includes the aforementioned high-density polyethylene resin, high-quality high-density polyethylene films with uniform surface and high strength can be provided by utilizing its high tensile properties. Furthermore, the high-density polyethylene film manufactured as described above exhibits low haze, high transparency, and high impact strength, making it readily applicable to polyethylene products and thus possessing high commercial value. In particular, it can be advantageously used in the manufacture of single-layer polyethylene packaging materials.

[0093] In the following description, embodiments of the present invention will be further described with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are for illustrative purposes only and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments within the scope and technical concept of the present invention, and naturally, such changes and modifications fall within the scope of the appended claims.

[0094] [Preparation Example 1]

[0095] 7.8 g of the composite transition metal compound was mixed with 1.1 kg of a toluene solution containing 10 wt% methylaluminoxane (MAO) to prepare a mixed solution with an Al / Zr ratio of 150. The mixture was stirred at room temperature for 1 hour to prepare a solution of the transition metal compound, wherein the composite transition metal compound included transition metal composition A ((tetramethylcyclopentadienyl)(n-butylcyclopentadienyl)zirconium dichloride), transition metal compound B (diphenylmethylene-(3-butyl-cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)-zirconium dichloride (IV)) and transition metal compound C (diphenylmethylene-(cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)-zirconium dichloride (IV)) (the molar ratio of the transition metal compounds was 1:0.5:1.8).

[0096] 250 g of silica (XP2402) was placed in a reactor, and 30 ml of purified toluene was added to prepare a silica slurry. A transition metal compound solution was injected into the silica slurry and stirred in an oil bath at 75°C for 3 hours to prepare a metallocene catalyst solution. The metallocene catalyst solution was separated into solid and liquid components, and the supernatant was removed to separate only the metallocene catalyst. The metallocene catalyst was washed three times with toluene and then vacuum dried at 60°C for 10 hours to recover 230 g of powdered mixed metallocene catalyst.

[0097] [Preparation Example 2] Except that the 3.5 g composite transition metal compound contains transition metal compound A, transition metal compound B and transition metal compound C in a molar ratio of 1:1.5:6, the powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0098] [Preparation Example 3] Except that the 12.3 g composite transition metal compound contains transition metal compound A, transition metal compound B and transition metal compound C in a molar ratio of 1:0.3:1.4, the powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0099] [Comparative Preparation Example 1] Except that the 5.9 g composite transition metal compound contains transition metal compounds A, B, and C in a molar ratio of 1:0.05:1.8, the powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0100] [Comparative Preparation Example 2] Except that the 4 g composite transition metal compound contains transition metal compound A, transition metal compound B and transition metal compound C in a molar ratio of 1:0.5:0.17, the powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0101] [Comparative Preparation Example 3]

[0102] Except for the preparation of the composite transition metal compound using 1.8 g of transition metal compound D ((n-butylcyclopentadienyl)(tetramethylcyclopentadienyl)zirconia chloride) and 5.0 g of transition metal compound B (diphenylmethylene-(3-butyl-cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)-zirconia dichloride(IV)), the powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0103] [Comparative Preparation Example 4]

[0104] In addition to preparing a composite transition metal compound using 1.2 g of transition metal compound E (bis(n-propylcyclopentadienyl)zirconia chloride), 0.8 g of transition metal compound B (diphenylmethylene-(3-butyl-cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)-zirconia(IV)) and 5 g of transition metal compound F ((dimethylmethylenesilyl)bis(2-methyl-4-phenylindenyl)zirconia), a powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0105] [Comparative Preparation Example 5]

[0106] In addition to preparing the composite transition metal compound using 1.8 g of transition metal compound G (bis(isobutylcyclopentadienyl)zirconia), 0.8 g of transition metal compound B (diphenylmethylene-(3-butyl-cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)-zirconia(IV)) and 3.8 g of transition metal compound ((dimethylmethylenesilyl)bis(2-methyl-4-phenylindenyl)zirconia), the powdered mixed metallocene catalyst was prepared in the same manner as in Preparation Example 1.

[0107] [Example 1] Using the catalyst prepared in Preparation Example 1, ethylene / 1-hexene polymerization was carried out at 90°C in a continuous gas-phase polymerization reactor including a fluidized bed. The reaction conditions are described in Table 2 below.

[0108] [Example 2] Except that the catalyst prepared in Preparation Example 2 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0109] [Example 3] Except that the catalyst prepared in Preparation Example 3 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0110] [Example 4] Except that the polymerization temperature was set at 80°C, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0111] [Comparative Example 1] Except that the catalyst prepared in Comparative Preparation Example 1 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0112] [Comparative Example 2] Except that the catalyst prepared in Comparative Preparation Example 2 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0113] [Comparative Example 3] Except that the catalyst prepared in Comparative Preparation Example 3 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0114] [Comparative Example 4] Except that the catalyst prepared in Comparative Preparation Example 4 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0115] [Comparative Example 5] Except that the catalyst prepared in Comparative Preparation Example 5 was used as the catalyst, the ethylene / 1-hexene polymerization reaction was carried out in the same manner as in Example 1.

[0116] [Table 1]

[0117] The physical properties of the polymers prepared in the above examples and comparative examples were measured as follows, and the results are shown in Table 2.

[0118] (1) Melt Flow Ratio (MFR) 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 ).

[0119] (2) Density Density was measured according to ASTM D 1505.

[0120] (3) Molecular weight Gel permeation chromatography-FTIR (GPC-FTIR) was performed using Polymer Char GPC-6. Molecular weight was measured at 160 °C using trichlorobenzene as the solvent.

[0121] (4) Thermal properties Thermal properties were measured using a differential scanning calorimeter (DSC, device name: DSC 2920, manufacturer: TA instrument). Specifically, the polymer was heated to 200 °C, held at that temperature for 5 minutes, cooled again to 20 °C, and then the temperature was increased again. The rate of temperature increase and decrease was controlled at 20 °C / min.

[0122] [Table 2]

[0123] The polyethylene polymers prepared in the following extrusion examples and comparative examples were used to manufacture films, and the physical properties of the films are listed in Table 3 below.

[0124] (5) Method for manufacturing polyethylene film The polyethylene polymers of Examples 1 to 4 and Comparative Examples 1 to 5 were extruded using a twin-screw extruder with an L / D of 42DML and a diameter of 25 mm at 245°C. The die temperature was maintained at 265°C. The T-DIE was adjusted to a size of 30 to 35 cm and a thickness of 770 to 780 μm to produce films.

[0125] (6) Sequential biaxial stretching process Biaxial stretching was performed using a PS002 machine from SDB Co., Ltd. First, a 10 cm thick sample was prepared using a press at 190°C. × A 10 cm × 1 mm sheet sample was prepared. The sheet was heated in an oven at 120°C to 125°C for 300 seconds, stretched at a speed of 200 % / s along the MD (machine direction), and then stretched along the TD (transverse direction).

[0126] (7) Simultaneous biaxial stretching process Biaxial stretching was performed using a KARO 5.0 machine from Burckner Co., Ltd. Polymer samples were prepared to size 9 cm × 9 cm. The prepared samples were stretched simultaneously in the machine direction (MD) and transverse direction (TD) at a speed of 200 % / s under heating conditions of 120°C to 130°C.

[0127] (8) Haze measurement Each sample was measured five times according to ASTM D 1003, and the average value was recorded.

[0128] (9) Clarity measurement Each sample was measured five times according to ASTM D 1003, and the average value was recorded.

[0129] [Table 3]

[0130] Referring to Tables 1 to 3, the mixed metallocene catalysts of Examples 1 to 4 comprise transition metal compounds of Formulas 1 to 3, thus producing polyolefin resins with a content of 0.94 g / cm³. 3Or even higher densities, and they are all capable of biaxial stretching at high ratios. However, it was confirmed that the high-density polyethylene polymers of Comparative Examples 3 to 5, prepared using catalysts that were not specific to the catalyst mixture of the present invention, cracked and therefore could not be stretched. Comparative Examples 1 and 2 included transition metal compounds of Formulas 1 to 3 of the present invention, but when the ratio of Formula 1:Formula 2:Formula 3 was not satisfied, they also could not be stretched, resulting in breakage or tearing during stretching, thus making them unprocessable. Therefore, it was confirmed that such biaxial stretching characteristics were exhibited when high-density polyethylene polymers were prepared using the mixed metallocene catalysts of the present invention in specific proportions. These results are considered to be attributed to the complex effects of the weight-average molecular weight, number-average molecular weight, molecular weight distribution, MFR characteristics, thermal properties, mechanical properties, crystallinity, etc., of the polymers produced by the mixed metallocene catalysts of the present invention.

[0131] Although the implementation methods have been described in detail above with examples and experimental examples, the scope of the implementation methods is not limited to the specific embodiments and should be interpreted in accordance with the appended patent claims.

Claims

1. A method for preparing high-density polyethylene, the method comprising: In the presence of a mixed metallocene catalyst, ethylene reacts with C4-C 20 α-olefin polymerization, wherein the mixed metallocene catalyst comprises transition metal compounds of formulas 1 to 3 below. The mixed metallocene catalyst comprises transition metal compounds in a molar ratio of Formula 1: Formula 2: Formula 3 = 1:0.2~3:1~7. [Formula 1] [Equation 2] [Formula 3] In equations 1 to 3, R a It is a C2-C6 alkylene group, R b and R c Each is independently a C1-C6 alkylene group. R1, R2, R3, R4, and R5 are each independently a C1-C5 alkyl group. X is a halogen, m, m1 and m2 are integers from 0 to 4, n is an integer from 0 to 3, and o is an integer from 1 to 4.

2. The method according to claim 1, in, The C4-C 20 α-olefins are C5-C8 α-olefins.

3. The method according to claim 1, in, Equation 1 is Equation 4 below, Equation 2 is Equation 5 below, and Equation 3 is Equation 6 below: [Formula 4] [Formula 5] [Formula 6] 。 4. The method according to claim 1, in, The polymerization temperature is between 60°C and 90°C.

5. The method according to claim 1, in, The mixed metallocene catalyst is a supported catalyst in which a transition metal compound and a co-catalyst are supported on a support.

6. The method according to claim 5, in, The co-catalyst is at least one selected from the group consisting of compounds represented by formulas 7 to 9 below: [Formula 7] [Formula 8] [Formula 9] [L-H] + [Z(A)4] - or [L] + [Z(A)4] - Among them, in equations 7 to 9, n is an integer greater than or equal to 2, R6 is a halogen, C1-C 20 Alkyl or halogen-substituted C1-C 20 alkyl, D is aluminum (Al) or boron (B), and R7, R8, and R9 are each independently halogenated, straight-chain, or branched C1-C. 20 Alkyl groups, halogen-substituted C1-C groups 20 Alkyl or C1-C 20 Alkoxy L is a neutral or cationic Lewis base, [LH] + and [L] + It is a Brønsted acid, Z is a group 13 element, and A is C6-C. 20 Aryl or C1-C 20 alkyl.

7. The method according to claim 5, in, The carrier is at least one selected from the group consisting of silicon dioxide, aluminum oxide, and magnesium oxide.

8. A method for reacting ethylene with C4-C in the presence of a mixed catalyst. 20 High-density polyethylene resin prepared from α-olefins, wherein, The high-density polyethylene resin has a content of 0.94 g / cm³. 3 Or higher density, 30 or higher PDI, and capable of stretching 4 times or more along the machine direction (MD) at 200 % / s at 120°C to 130°C, and then sequentially biaxially stretching 4 times or more along the transverse direction (TD), or capable of simultaneously biaxially stretching 4×4 times or more along both MD and TD.

9. The high-density polyethylene resin according to claim 8, in, The mixed metallocene catalyst comprises transition metal compounds of formulas 1 to 3 below: [Formula 1] [Equation 2] [Formula 3] In equations 1 to 3, R a It is a C2-C6 alkylene group, R b and R c Each of them is independently a C1-C6 alkylene group, and R1, R2, R3, R4, and R5 are each independently a C1-C5 alkyl group. X is a halogen, m and m1 are integers from 0 to 4, n is an integer from 0 to 3, and o is an integer from 1 to 4.

10. The high-density polyethylene resin according to claim 9, in, The mixed metallocene catalyst comprises transition metal compounds in a molar ratio of Formula 1: Formula 2: Formula 3 = 1:0.2~3:1~7.

11. The high-density polyethylene resin according to claim 8, in, The C4-C 20 α-olefins are C5-C8 α-olefins.

12. The high-density polyethylene resin according to claim 8, in, The high-density polyethylene resin has a melt flow rate (MFR) of 40 or higher.

13. The high-density polyethylene resin according to claim 8, in, The high-density polyethylene resin has a crystallinity of 80 or lower (Xc).

14. A high-density polyethylene film comprising the high-density polyethylene resin according to claim 8.

15. The high-density polyethylene film according to claim 14, in, The high-density polyethylene film has a haze of 25% or less as measured according to ASTM D1003.

16. The high-density polyethylene film according to claim 14, in, The high-density polyethylene film has a transparency of 70% or higher as measured according to ASTM D1003.

17. The high-density polyethylene film according to claim 14, in, The high-density polyethylene film has an impact strength of 120 gf or higher as measured according to ASTM D1709.

18. A packaging material, said packaging material being manufactured using the film of any one of claims 14 to 17.

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