Polyethylene and composition comprising same

Abstract

The present invention provides polyethylene having improved resistance to environmental stress cracking as well as retaining excellent processability and mechanical properties when combined with recycled polyethylene, and a polyethylene composition comprising same.

Description

Polyethylene and compositions containing the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0133319 filed September 30, 2024 and Korean Patent Application No. 10-2025-0141620 filed September 29, 2025, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0003]

[0004] The present invention relates to polyethylene that improves resistance to environmental stress cracking while maintaining excellent mechanical properties and processability when combined with recycled polyethylene, and to a polyethylene composition containing the same.

[0005]

[0006] The demand for polyethylene resin is steadily increasing and it is being used in various applications.

[0007]

[0008] Recently, as environmental concerns have intensified, regulations aimed at curbing carbon dioxide emissions have been strengthened. In particular, as environmental pollution caused by the increased use of plastics has emerged as a serious issue, regulations at the manufacturing stage are being tightened, such as mandating the use of recycled resins, primarily in the United States. Consequently, manufacturers are required to add a certain amount of recycled resin when producing resin molded products, and eco-friendliness ratings are assigned based on the recycled resin content.

[0009]

[0010] However, since recycled resin is already processed, its properties have already changed during the high-temperature processing, resulting in significantly lower impact strength, tensile strength, chemical resistance, and thermal stability compared to conventional virgin resin. To address this problem, a method has been attempted to include a certain level of virgin resin in a composition containing recycled resin.

[0011]

[0012] Accordingly, there is an urgent need for research and development of polyethylene with improved resistance to environmental stress cracking, along with excellent mechanical properties and processability, as a virgin resin to be blended with such recycled resin.

[0013]

[0014] The present invention aims to provide polyethylene that improves resistance to environmental stress cracking while maintaining excellent mechanical properties and processability when combined with recycled polyethylene, and a polyethylene composition containing the same.

[0015]

[0016] According to one embodiment of the invention,

[0017] Density is 0.935 g / cm³ 3 That is all,

[0018] In a GPC curve graph where the x-axis is log MW and the y-axis is dw / dlogMw, the integral value in the region where the Log MW value is 4.5 or less is between 30% and 70% of the total integral value, and

[0019] The SCB content is 2.0 (pieces / 1000C) or more and 8.0 (pieces / 1000C) or less, and

[0020] The BOCD (Broad Orthogonal Co-monomer Distribution Index) is 2.2 or higher, and

[0021] Those with a BMI (bimodality index) of 2.0 or higher

[0022] Polyethylene is provided.

[0023]

[0024] In addition, the present invention provides a polyethylene composition comprising virgin polyethylene (or Booster PE) and recycled polyethylene (PCW PE, Post consumer waste polyethylene), wherein the virgin polyethylene comprises the polyethylene described above.

[0025]

[0026] According to the present invention, by optimizing the molecular structure along with density to improve the ratio of the low molecular weight region, SCB content, BOCD index, and BMI index, it is possible to provide polyethylene that improves resistance to environmental stress cracking while maintaining excellent mechanical properties and processability when combined with recycled polyethylene.

[0027]

[0028] In the present invention, terms such as first, second, etc. are used to describe various components, and these terms are used solely for the purpose of distinguishing one component from another component.

[0029]

[0030] Furthermore, the terms used herein are used merely to describe exemplary embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0031]

[0032] Additionally, terms such as "approximately" and "substantially" used throughout this specification are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the stated meaning, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding the invention.

[0033]

[0034] In addition, in this specification, "part by weight" refers to a relative concept in which the weight of one substance is expressed as a ratio to the weight of another substance. For example, in a mixture containing 50 g of substance A, 20 g of substance B, and 30 g of substance C, the amounts of substance B and substance C are 40 parts by weight and 60 parts by weight, respectively, based on 100 parts by weight of substance A.

[0035]

[0036] In addition, "weight % (% by weight)" refers to an absolute concept in which the weight of a substance is expressed as a percentage of the total weight. In the mixture given as an example above, the content of substance A, substance B, and substance C is 50 weight%, 20 weight%, and 30 weight%, respectively, out of 100% of the total weight of the mixture. At this time, the total content of each component does not exceed 100 weight%.

[0037]

[0038] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0039]

[0040] The present invention will be described in more detail below.

[0041]

[0042] According to one embodiment of the invention, polyethylene is provided in which the molecular structure is optimized along with the density to improve the ratio of the low molecular weight region, SCB content, BOCD index, and BMI index, so as to improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties and processability even when combined with recycled polyethylene.

[0043]

[0044] Specifically, the polyethylene of the present invention has a density of 0.935 g / cm³ 3 In the GPC curve graph where the x-axis is log MW and the y-axis is dw / dlogMw, the integral value of the region where the Log MW value is 4.5 or less is 30% or more and 70% or less of the total integral value, the SCB content is 2.0 (pieces / 1000C) or more and 8.0 (pieces / 1000C) or less, the BOCD index (Broad Orthogonal Co-monomer Distribution Index) is 2.2 or more, and the BMI index (bimodality index) is 2.0 or more.

[0045]

[0046] In particular, the above polyethylene can effectively improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties and processability, such as flexural modulus and drop impact strength, when blended with recycled polyethylene by optimizing the molecular structure along with density to optimize the ratio of the low molecular weight region, SCB content, BOCD index, and BMI index to a predetermined range.

[0047]

[0048] The polyethylene of the present invention will be described in more detail below.

[0049]

[0050] Specifically, the polyethylene according to one embodiment of the present invention may be an ethylene homopolymer or an ethylene / alpha-olefin copolymer.

[0051]

[0052] The above alpha-olefin may be one or more selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and mixtures thereof.

[0053]

[0054] For example, the polyethylene according to the present invention may not contain the aforementioned alpha-olefin or may contain it in an amount of 10 weight% or less. That is, the alpha-olefin may be contained in an amount of 0 to 10 weight% or less. Specifically, the alpha-olefin may be 8 weight% or less, or 6.5 weight% or less, or 5 weight% or less, or 4.5 weight% or less, or 4 weight% or less, or 3.5 weight% or less, or 3 weight% or less, or 2.5 weight% or less, or 2.2 weight% or less, or 2 weight% or less, or 1.8 weight% or less, or 1.5 weight% or less, but is not limited thereto. In addition, when the polyethylene is an ethylene / alpha-olefin copolymer, the alpha-olefin may be 0.1 wt% or more, or 0.3 wt% or more, or 0.5 wt% or more, or 0.7 wt% or more, or 0.85 wt% or more, or 0.9 wt% or more, or 1.0 wt% or more, or 1.2 wt% or more, but is not limited thereto.

[0055]

[0056] For example, when the polyethylene according to the present invention is a copolymer, 1-hexene or 1-butene can be used as the alpha-olefin copolymerized with ethylene, and more specifically, 1-hexene can be used.

[0057]

[0058] In addition, the polyethylene may be a dry blend of one or more or two or more ethylene homopolymers as described above, or a dry blend of one or more or two or more ethylene / alpha-olefin copolymers.

[0059]

[0060] Meanwhile, the polyethylene according to one embodiment of the present invention has a density (ASTM D 1505, 23 °C) of 0.935 g / cm³ 3 Above or 0.935 g / cm³ 3 From 0.960 g / cm³ 3 It may be high-density polyethylene (HDPE) satisfying the following.

[0061]

[0062] More specifically, the density of the polyethylene is 0.938 g / cm³ 3 Above, 0.940 g / cm³ 3 Above, 0.942 g / cm³ 3 Above, 0.945 g / cm³ 3 Above, or 0.946 g / cm³ 3 It may be greater than 0.958 g / cm³ 3 Below, 0.956 g / cm³ 3 Below, 0.955 g / cm³ 3 Less than or equal to 0.952 g / cm³ 3 It may be less than.

[0063]

[0064] In the present invention, density (g / cm³) 3) can be measured according to ASTM D 1505 standards, and, for example, may be a value measured at 23 ℃. For example, such density (g / cm³) 3 The method for measuring ) is as described in the experimental examples below.

[0065]

[0066] When the density of the polyethylene satisfies the range described above, it is possible to improve environmental stress cracking resistance (ESCR) even when mixed with recycled polyethylene, while minimizing the degradation of mechanical properties such as flexural modulus.

[0067]

[0068] Meanwhile, in the above polyethylene, in a GPC curve graph where the x-axis is log MW and the y-axis is dw / dlogMw, the integral value of the region where the Log MW value is 4.5 or less is 30% or more to 70% or less of the total integral value.

[0069]

[0070] Specifically, the integral value of the region where the Log Mw is 4.5 or less may be 32% or more, 35% or more, 38% or more, 40% or more, 45% or more, 48% or more, 49% or more, or 50% or more, in order to simultaneously secure excellent mechanical properties and processability with high load strength along with excellent environmental stress crack resistance when mixing the polyethylene and recycled polyethylene. In addition, in terms of securing excellent environmental stress cracking resistance (ESCR) at the same density after mixing with recycled polyethylene, the integral value of the region where Log Mw is 4.5 or less may be 68% or less, 65% or less, 62% or less, 60% or less, 58% or less, 57.5% or less, 57% or less, 56.5% or less, 56% or less, 55.5% or less, 55% or less, 54.7% or less, or 54.4% or less.

[0071]

[0072] By having an integral value in the region where Log Mw is 4.5 or less as described above, the proportion of the low molecular weight region within the molecular structure of polyethylene can be increased, and when combined with recycled polyethylene, environmental stress cracking resistance (ESCR) can be improved while maintaining excellent processability along with excellent mechanical properties such as high load strength.

[0073]

[0074] In addition, for the polyethylene, in a GPC curve graph where the x-axis is log Mw and the y-axis is dw / dlogMw, the integral value of the region where Log Mw is 5.5 or higher is 5% or more to 20% or less of the total integral value.

[0075]

[0076] Specifically, the integral value of the region where the Log Mw is 5.5 or higher may be 7% or more, 8% or more, 9% or more, 10% or more, 10.5% or more, 11% or more, 11.5% or more, 12% or more, 12.5% ​​or more, 12.9% or more, 13% or more, or 13.2% or higher, so as to improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties when mixing the polyethylene in the low molecular weight region described above with recycled polyethylene. Additionally, considering excellent mechanical properties with high density after mixing with recycled polyethylene, it may be 18% or less, 17.8% or less, 17.5% or less, 17.3% or less, 17% or less, 16.9% or less, or 16.8% or less.

[0077]

[0078] By having an integral value in the region where Log Mw is 5.5 or higher as described above, the ratio of the polymer region within the molecular structure of the new polyethylene can be strengthened, and the environmental stress cracking resistance (ESCR) can be simultaneously improved to an excellent degree along with the excellent mechanical properties of recycled polyethylene.

[0079]

[0080] Meanwhile, the polyethylene according to the present invention may have an optimized molecular weight distribution (PDI, Mw / Mn) by optimizing the molecular structure along with the density as described above, thereby strengthening the proportion of the low molecular weight region and maintaining the proportion of the high molecular weight region.

[0081]

[0082] Specifically, the polyethylene may have a molecular weight distribution (Mw / Mn) of 20 or more, or 20 to 50. Preferably, the molecular weight distribution (Mw / Mn) of the polyethylene may be 20.5 or more, 21.0 or more, 21.5 or more, 22.0 or more, 22.5 or more, 23.0 or more, 23.5 or more, or 24.0 or more, and may also be 45 or less, 40 or less, 38 or less, 35 or less, 32 or less, 30 or less, 28 or less, 26.5 or less, 26.0 or less, or 25.5 or less.

[0083]

[0084] By having the molecular weight distribution (Mw / Mn) as described above, the ratio of the low molecular weight region within the molecular structure of the polyethylene is strengthened while the ratio of the high molecular weight region is maintained, and when combined with recycled polyethylene, excellent mechanical properties are maintained and environmental stress cracking resistance (ESCR) can be improved.

[0085]

[0086] For example, the ratio of the region where the Log MW value is 4.5 or less or 5.5 or more in the above GPC curve graph and the molecular weight distribution (PDI, polydispersity index) are measured using gel permeation chromatography (GPC). Specifically, it can be measured using the polystyrene conversion test method with gel permeation chromatography (GPC, manufactured by Polymer Char).

[0087]

[0088] Here, the polydispersity index (PDI) can be calculated by measuring the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polyethylene and dividing the weight-average molecular weight by the number-average molecular weight.

[0089]

[0090] Specifically, the Polymer Char GPC-IR instrument is used as the gel permeation chromatography (GPC) device, and a Polymer Laboratories PLgel MIX-B 300 mm long column can be used. In this case, the measurement temperature is 160 o C, and 1,2,4-trichlorobenzene can be used as a solvent, and a flow rate of 1 mL / min can be applied. Each of the above polyethylene samples was analyzed using a GPC analyzer (GPC-IR) in 1,2,4-trichlorobenzene containing 0.0125% butylated hydroxytoluene (BHT) at 160 o C, pre-treated by dissolving for 2 hours, prepared at a concentration of 10 mg / 10 mL, and supplied in an amount of 200 microliters (μL). Values ​​of Mw and Mn can be derived using a calibration curve formed using a polystyrene standard specimen. Nine types of polystyrene standard specimens with weight-average molecular weights can be used: 2000 g / mol, 10000 g / mol, 30000 g / mol, 70000 g / mol, 200000 g / mol, 700000 g / mol, 2000000 g / mol, 4000000 g / mol, and 10000000 g / mol.

[0091]

[0092] In addition, the polyethylene may have a weight-average molecular weight of 100,000 g / mol or more, or between 100,000 g / mol and 500,000 g / mol. Preferably, the weight-average molecular weight of the polyethylene may be 105,000 g / mol or more, or 110,000 g / mol or more, or 115,000 g / mol or more, or 120,000 g / mol or more, or 122,000 g / mol or more, or 125,000 g / mol or more. However, considering compatibility with recycled polyethylene, the weight-average molecular weight may be 480,000 g / mol or less, or 450,000 g / mol or less, or 400,000 g / mol or less, or 350,000 g / mol or less, or 300,000 g / mol or less, or 250,000 g / mol or less, or 200,000 g / mol or less, or 180,000 g / mol or less, or 150,000 g / mol or less, or 140,000 g / mol or less.

[0093]

[0094] By having the weight average molecular weight (Mw) as described above, the molecular weight distribution of the polyethylene is optimized, and when combined with recycled polyethylene, the environmental stress cracking resistance (ESCR) can be improved along with excellent mechanical properties.

[0095]

[0096] Meanwhile, the SCB content derived from GPC-IR analysis relative to the total moles of the polyethylene is 2.0 (units / 1000C) or more and 8.0 (units / 1000C) or less, as the number of short chain branches per 1000 carbon atoms, i.e., the number of short branch chains with 2 to 7 carbon atoms ( / 1000C).

[0097]

[0098] The SCB content of the above polyethylene is 2.3 (pieces / 1000C) or more, 2.5 (pieces / 1000C) or more, 2.6 (pieces / 1000C) or more, 2.7 (pieces / 1000C) or more, 2.8 (pieces / 1000C) or more, 2.9 (pieces / 1000C) or more, 3.0 (pieces / 1000C) or more, 3.2 (pieces / 1000C) or more, 3.5 (pieces / 1000C) or more, 3.7 (pieces / 1000C) or more, 4.0 (pieces / 1000C) or more, 4.1 (pieces / 1000C) or more, 4.2 (pieces / 1000C) or more, in order to improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties when mixed with recycled polyethylene. 4.3 (pieces / 1000C) or higher, 4.5 (pieces / 1000C) or higher, or 4.6 (pieces / 1000C) or higher, and also 8.0 (pieces / 1000C) or lower, 7.8 (pieces / 1000C) or lower, 7.5 (pieces / 1000C) or lower, 7.3 (pieces / 1000C) or lower, 7.0 (pieces / 1000C) or lower, 6.8 (pieces / 1000C) or lower, 6.5 (pieces / 1000C) or lower, 6.3 (pieces / 1000C) or lower, 6.2 (pieces / 1000C) or lower, 6.0 (pieces / 1000C) or lower, 5.8 (pieces / 1000C) or lower, 5.5 (pieces / 1000C) or lower, or 5.2 (pieces / 1000C) or lower there is.

[0099]

[0100] In the present invention, SCB (Short Chain Branch) refers to a short chain bonded to the polymer main chain in a branch-like form in polyethylene, specifically a short branched chain having 2 to 7 carbon atoms bonded to the main chain of polyethylene. It is a short branched chain formed when an alpha-olefin having 4 or more carbon atoms, such as 1-butene, 1-hexene, or 1-octene, is used as a comonomer, and its content may be proportional to the content of the α-olefin monomer included in the polymer chains. SCB content refers to the number of branched chains having 2 to 7 carbon atoms per 1,000 carbon atoms (unit: number / 1,000 C), and Proton Nuclear Magnetic Resonance (PNR, 1 It can be calculated through analysis using H-NMR or gel chromatography (GPC-IR). In the present invention, it was calculated by measuring at 160°C using GPC-IR equipment, and the specific analysis method is explained in detail in the experimental examples below.

[0101]

[0102] Meanwhile, the above polyethylene has a BOCD index (Broad Orthogonal Co-monomer Distribution Index) of 2.2 or higher, or from 2.2 to 10.0 or lower.

[0103]

[0104] The BOCD structure used in this specification refers to a structure in which the content of short chain branches (SCB) in polyethylene is concentrated in the high molecular weight main chain, for example, a structure in which the content of comonomers such as alpha olefins is concentrated in the high molecular weight main chain, that is, a structure in which the content of short chain branches (SCB) increases as it goes toward the high molecular weight.

[0105]

[0106] The BOCD index can be obtained by using a GPC-IR device to continuously and simultaneously measure the weight-average molecular weight, molecular weight distribution, and SCB content, plotting a molecular weight distribution curve with the logarithm of the weight-average molecular weight (M) (log M) as the x-axis and the molecular weight distribution (dwt / dlog M) corresponding to the logarithm as the y-axis, measuring the SCB (Short Chain Branch) content (content of branches with 2 to 7 carbon atoms per 1,000 carbon atoms, unit: number / 1,000C) at the left and right boundaries of the middle 60% excluding the left and right ends relative to the total area, and then calculating according to the following Equation 1 using the measured values. In this case, the SCB content on the high molecular weight side and the SCB content on the low molecular weight side refer to the SCB content values ​​at the right boundary and the left boundary, respectively, within the middle 60% range excluding the left and right ends.

[0107] [Equation 1]

[0108]

[0109] In the above Equation 1, the SCB content in the high molecular weight region and the SCB content in the low molecular weight region represent the SCB content value at logMw corresponding to 20% of the high molecular weight region and the low molecular weight region, respectively. The high molecular weight log Mw and low molecular weight log Mw values ​​are the logMw values ​​corresponding to 20% of the high molecular weight region and the low molecular weight region, respectively, relative to the total area of ​​the y-axis (dw / dlogMw) and x-axis (logMw) curves obtained through GPC analysis.

[0110]

[0111] In this case, if the BOCD index is 0 or less, it is not a polymer with a BOCD structure, and if it is greater than 0, it is considered to be a polymer with a BOCD structure; the larger the value, the more it has a structure with a high SCB (Short Chain Branch) content in the high molecular weight region.

[0112]

[0113] The polyethylene according to one embodiment of the invention has a high BOCD index of 2.2 or higher, thereby having a high comonomer content in the high molecular weight portion, and as a result, can exhibit high environmental stress crack resistance along with excellent mechanical properties.

[0114]

[0115] Specifically, the BOCD index of the polyethylene may be 2.22 or higher, 2.25 or higher, 2.28 or higher, or 2.30 or higher, and may also be 9.0 or lower, 8.5 or lower, 8.0 or lower, 7.5 or lower, 7.0 or lower, or 6.5 or lower.

[0116]

[0117] Meanwhile, the above polyethylene has a BMI (bimodality index) of 2.0 or higher, or 2.0 or higher to 5.0 or lower.

[0118]

[0119] The BMI index used in this specification, namely the bimodality index (BMI), refers to the distance between peaks in a molecular weight distribution curve derived with the logarithm of the weight-average molecular weight (M) (log M) as the x-axis and the molecular weight distribution (dwt / dlog M) for said logarithm as the y-axis. As the molecular weight distribution curve is unimodal with one peak, the BMI converges to 0, whereas in a bimodal molecular weight distribution curve with two peaks, the BMI increases as the distance between peaks increases.

[0120]

[0121] The BMI (bimodality index) can be obtained by measuring the weight-average molecular weight using a GPC-IR device, plotting a molecular weight distribution curve with the logarithm of the weight-average molecular weight (Mw) (log Mw) on the x-axis and the molecular weight distribution (dwt / dlog M) for the logarithm on the y-axis, separating the peaks (peak A, peak B) forming the low molecular weight fraction and the high molecular weight fraction, measuring each peak, and then calculating according to Equation 2 below using the measured values.

[0122] [Equation 2]

[0123]

[0124] In the above Equation 2,

[0125] Peaks A and B are the peaks (peak A, peak B) of the low molecular weight fraction and the high molecular weight fraction, respectively, when the peaks (peak A, peak B) forming the low molecular weight fraction and the high molecular weight fraction are separated using peak deconvolution (Gaussian Probability Function) on a GPC curve graph for polyethylene where the x-axis is log MW and the y-axis is dw / dlogMw.

[0126] logMw(peak A) and logMw(peak B) are the logMw values ​​at the maximum dw / dlogMw for each peak, and

[0127] AR(peak A) and AR(peak B) are the area ratio (AR) of each peak relative to the total area of ​​the derived peaks A and B.

[0128]

[0129] Specifically, the BMI (bimodality index) of the polyethylene may be 2.2 or higher, 2.35 or higher, 2.5 or higher, or 2.55 or higher, and may also be 4.8 or lower, 4.5 or lower, 4.0 or lower, 3.5 or lower, 3.0 or lower, or 2.8 or lower.

[0130]

[0131] In the present invention, the BMI (bimodality index) refers to the distribution pattern of polyethylene according to molecular weight. In the present invention, the area was calculated by deconvolving each peak in the GPC curve graph derived through GPC-IR and integrating the result, and the specific analysis method is explained in detail in the experimental examples below.

[0132]

[0133] Meanwhile, the polyethylene according to the present invention can optimize the molecular structure along with the density as described above, thereby enhancing the ratio of the low molecular weight region, SCB content, BOCD index, and BMI index, while simultaneously optimizing the melt index.

[0134]

[0135] The above polyethylene has a melt index (MI). 2.16 (ASTM D 1238, 190 ℃, 2.16 kg) may be 0.10 g / 10 min to 1.2 g / 10 min. Preferably, the melt index (MI) of the polyethylene 2.16 (ASTM D 1238, 190 ℃, 2.16 kg) may be 0.15 g / 10 min or more, 0.18 g / 10 min or more, 0.2 g / 10 min or more, or 0.22 g / 10 min or more, and 1.18 g / 10 min or less, 1.15 g / 10 min or less, 1.12 g / 10 min or less, or 1.10 g / 10 min or less. As described above, the melt index (MI) of polyethylene 2.16 By having ), the molecular weight distribution of polyethylene is optimized, and when combined with recycled polyethylene, environmental stress cracking resistance (ESCR) can be improved along with excellent mechanical properties.

[0136]

[0137] By possessing the melt index described above, the molecular weight of polyethylene is optimized, and when blended with recycled polyethylene, environmental stress cracking resistance (ESCR) can be improved along with excellent mechanical properties. In particular, considering compatibility with recycled polyethylene, the melt index (MI) of polyethylene 2.16 , ASTM D 1238, 190 ℃, 2.16 kg) is preferably 0.2 g / 10 min to 1.2 g / 10 min.

[0138]

[0139] In addition, the above polyethylene has a flexural modulus of 10,000 kgf / cm² as measured by the ASTM D 790 method. 2 or more than 10,000 kgf / cm² 2 Up to 17,000 kgf / cm² 2 It may be. Preferably, the flexural modulus of the polyethylene is 10,500 kg / cm² 2 Above, or 11,000 kg / cm² 2 Above, or 11,500 kg / cm² 2 or more than 12,000 kg / cm² 2 Above, or 12,100 kg / cm² 2 It could be more than that.

[0140]

[0141] For example, the method for measuring the physical properties of the polyethylene, namely density, low molecular weight ratio, SCB content, BOCD index, and BMI index, etc., is as described in Test Example 1 below. However, the method for measuring the physical properties of the polyethylene, namely density, low molecular weight ratio, SCB content, BOCD index, and BMI index, etc., is not limited thereto and may be measured by other methods known in the technical field to which the present invention belongs.

[0142]

[0143] Meanwhile, the polyethylene of the present invention can be produced by homopolymerizing ethylene in the presence of a metallocene catalyst in a slurry loop process, or by copolymerizing ethylene with a comonomer such as an alpha-olefin, and a more detailed synthesis method can be referenced in the examples.

[0144]

[0145] For example, the polyethylene may be a dry blend of one or more ethylene homopolymers or two or more ethylene copolymers prepared in the presence of a metallocene catalyst as described above, or a dry blend of one or more ethylene / alpha-olefin copolymers or two or more ethylene / alpha-olefin copolymers.

[0146]

[0147] In addition, the above-mentioned novel polyethylene may be manufactured by introducing hydrogen gas in the presence of a catalyst composition comprising one first metallocene compound represented by the following chemical formula 1 and two or more second metallocene compounds represented by the following chemical formula 2.

[0148] [Chemical Formula 1]

[0149] (Cp 1 R a ) n (Cp 2 R b )M 1 Z 1 3-n

[0150] In the above chemical formula 1,

[0151] M 1 It is a Group 4 transition metal;

[0152] Cp 1 and Cp 2 are respectively cyclopentadiennyl, and these are C 1-20 Substituted with or unsubstituted with hydrocarbons;

[0153] R a and R b are identical or different from each other, and each independently hydrogen, C1-20 Alkyl, C 1-20 Alkoxy, C 2-20 Alkoxyalkyl, C 6-20 Aril, C 6-20 Aryloxy, C 2-20 Alkenyl, C 7-40 Alkylaryl, C 7-40 Arylalkyl, C 8-40 Aryl alkenil, C 2-20 C comprising alkynyl, or one or more heteroatoms selected from the group consisting of N, O, and S. 2-20 It is heteroaryl, provided that R a and R b At least one of them is C 1-20 alkyl or C 7-20 It is an arylalkyl, and one of the others is C 2-20 It is an alkoxyalkyl;

[0154] Z 1 Silver is a halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 7-40 Alkylaryl, C 7-40 Arylalkyl, C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkylidene, substituted or unsubstituted amino group, C 2-20 Alkylalkoxy, or C 7-40 It is an aryl alkoxy;

[0155] n is 1 or 0 and;

[0156] [Chemical Formula 2]

[0157]

[0158] In the above chemical formula 2,

[0159] C1 is any one of the ligands represented by the following chemical formulas 3 to 6, and

[0160] [Chemical Formula 3]

[0161]

[0162] [Chemical Formula 4]

[0163]

[0164] [Chemical Formula 5]

[0165]

[0166] [Chemical Formula 6]

[0167]

[0168] In the above chemical formulas 3 to 6,

[0169] R1 to R6 are identical or different from one another, and each independently contains hydrogen, C 1-30 Alkyl, C 1-30 Alkoxy, C 2-30 Alkoxyalkyl, C 6-30 Aril, C 6-30 Aryloxy, C 2-30 Alkenyl, C 2-30 Alkinyl, C 3-30 Cycloalkyl, C 7-40 Alkylaryl, C 8-40 Alkenylaryl, C 8-40 Alkynylaryl, C 7-40 Arylalkyl, C 8-40 Aryl alkenyl, or C 8-40 It is Arylalkinil, and

[0170] M is Ti, Zr, or Hf, and

[0171] Z is -O-, -S-, -NR7- or -PR7-, and

[0172] R7 is hydrogen, C 1-30 Alkyl, C 6-30 Aril, C 2-30 Alkenyl, C 2-30 Alkinyl, C 3-30 Cycloalkyl, C 7-40 Alkylaryl, C 8-40 Alkenylaryl, C 8-40 Alkynylaryl, C 7-40 Arylalkyl, C 8-40 Aryl alkenil, C 8-40 Arylalkinyl, C 1-30 Alkoxysilyl group, C 6-30 Aryloxysilyl, C 1-30 Alkylsilyl group, or C 1-30 It is a silylalkyl group, and

[0173] X1 and X2 may be identical or different from each other and each independently halogen, C 1-30 Alkyl, C 2-30 Alkenyl, C 7-30 Alkylaryl, C 7-30 Arylalkyl, C 6-20 Aryl, substituted or unsubstituted C 1-30 Alkylidene, substituted or unsubstituted amino group, C 2-30 Alkylalkoxy, or C 7-30 It is an aryl alkoxy, and

[0174] T is or And,

[0175] T1 is C, Si, Ge, Sn, or Pb, and

[0176] Y1 is hydrogen, hydrogen, C 1-30 Alkyl, C 1-30 Alkoxy, C 2-30 Alkoxyalkyl, C 6-30 Aril, C 6-30 Aryloxy, C 2-30 Alkenyl, C 2-30 Alkinyl, C 3-30 Cycloalkyl, C 7-40 Alkylaryl, C 8-40 Alkenylaryl, C 8-40 Alkynylaryl, C 7-40 Arylalkyl, C 8-40 Aryl alkenyl, or C 8-40 Arylalkinyl, silyl group (-SiH3), C 1-30 Alkoxysilyl group, C 2-30 Alkoxyalkylsilyl group, C 6-30 Aryloxysilyl, C 1-30 Haloalkyl, C 6-30 Haloaryl, or -NR9R 10 And,

[0177] Y2 is C 2-30 Alkoxyalkyl, or C 7-40 It is an aryloxyalkyl, and

[0178] R9 and R 10 Each independently hydrogen, C 1-30 Alkyl, C 6-30 Aril, C 2-30 Alkenyl, C2-30 Alkinyl, C 3-30 Cycloalkyl, C 7-40 Alkylaryl, C 8-40 Alkenylaryl, C 8-40 Alkynylaryl, C 7-40 Arylalkyl, C 8-40 Aryl alkenyl, or C 8-40 They are arylalkynyl, or linked together to form aliphatic or aromatic rings.

[0179]

[0180] Meanwhile, unless otherwise specifically limited in this specification, the following terms may be defined as follows.

[0181]

[0182] Halogens can be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

[0183]

[0184] C 1-30 The alkyl group may be a straight-chain, branched-chain, or cyclic alkyl group. Specifically, C 1-20 The alkyl group is C 1-15 Straight-chain alkyl group; C 1-10 Straight-chain alkyl group; C 1-5 Straight-chain alkyl group; C 3-20 Branched or cyclic alkyl group; C 3-15 Branched or cyclic alkyl group; or C 3-10 It may be a branched chain or a cyclic alkyl group. More specifically, C 1-20 The alkyl group of may be a methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, neo-pentyl group, or cyclohexyl group, etc.

[0185]

[0186] C 2-30 The alkenyl group can be a straight-chain, branched-chain, or cyclic alkenyl group. Specifically, C 2-30 The alkenyl group is C 2-20 Straight-chain alkenyl group, C 2-10 Straight-chain alkenyl group, C2-5 Straight-chain alkenyl group, C 3-20 Branched-chain alkenyl group, C 3-15 Branched-chain alkenyl group, C 3-10 Branched-chain alkenyl group, C 5-20 The cyclic alkenyl group or C 5-10 It may be a cyclic alkenyl group. More specifically, C 2-20 The alkenyl group of may be an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, or a cyclohexanyl group, etc.

[0187]

[0188] C 6-30 Aryl can refer to monocyclic, bicyclic, or tricyclic aromatic hydrocarbons. Specifically, C 6-30 The aryl group can be a phenyl group, a naphthyl group, or anthracenyl group, etc.

[0189]

[0190] C 7-40 Alkylaryl may refer to a substituent in which one or more hydrogens of an aryl are substituted by an alkyl group. Specifically, C 7-40 The alkylaryl may be methylphenyl, ethylphenyl, n-propylphenyl, iso-propylphenyl, n-butylphenyl, iso-butylphenyl, tert-butylphenyl, or cyclohexylphenyl, etc.

[0191]

[0192] C 7-40 Arylalkyl may refer to a substituent in which one or more hydrogens of an alkyl group are substituted by an aryl group. Specifically, C 7-40 The arylalkyl group may be a benzyl group, phenylpropyl or phenylhexyl, etc.

[0193]

[0194] The above C 1-20 Examples of alkoxy groups include methoxy groups, ethoxy groups, phenyloxy groups, cyclohexyloxy groups, etc., but are not limited to these.

[0195]

[0196] The above C 2-20The alkoxyalkyl group is a functional group in which one or more hydrogens of the alkyl group described above are substituted with an alkoxy group, specifically, alkoxyalkyl groups such as methoxymethyl group, methoxyethyl group, ethoxymethyl group, iso-propoxymethyl group, iso-propoxyethyl group, iso-propoxyhexyl group, tert-butoxymethyl group, tert-butoxyethyl group, tert-butoxyhexyl group; or aryloxyalkyl groups such as phenoxyhexyl group, but is not limited thereto.

[0197]

[0198] The above C 1-20 alkylsilyl group or C 1-20 The alkoxysilyl group is a functional group in which 1 to 3 hydrogens of -SiH3 are substituted with 1 to 3 alkyl groups or alkoxy groups as described above, and specifically, examples include alkylsilyl groups such as methylsilyl, dimethylsilyl, trimethylsilyl, dimethylethylsilyl, diethylmethylsilyl, or dimethylpropylsilyl; alkoxysilyl groups such as methoxysilyl, dimethoxysilyl, trimethoxysilyl, or dimethoxyethoxysilyl; and alkoxyalkylsilyl groups such as methoxydimethylsilyl, diethoxymethylsilyl, or dimethoxypropylsilyl, but are not limited thereto.

[0199]

[0200] The above C 1-20 The silylalkyl group is a functional group in which one or more hydrogens of the alkyl group described above are substituted with a silyl group, and specifically, examples include -CH2-SiH3, methylsilylmethyl group or dimethylethoxysilylpropyl group, but are not limited thereto.

[0201]

[0202] The above sulfonate group has the structure -O-SO2-R', where R' is C 1-20 It may be an alkyl group. Specifically, C 1-20 Sulfonate groups include methanesulfonate groups or phenylsulfonate groups, but are not limited to these.

[0203]

[0204] The above heteroaryl comprises one or more of N, O, and S as heteroelements, C 2-20 As heteroaryls, specific examples include xanthene, thioxanthen, thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, acridyl group, pyridazine group, pyrazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, phthalazinyl group, pyridopyrimidinyl group, pyridopyrazinyl group, pyrazinopyrazinyl group, isoquinoline group, indole group, carbazole group, benzoxazole group, benzimidazole group, benzothiazole group, benzocarbazole group, benzothiophen group, dibenzothiophen group, benzofuranyl group, phenanthroline, There are isooxazolyl groups, thiadiazolyl groups, phenothiazinyl groups and dibenzofuranyl groups, but are not limited to these.

[0205]

[0206] The substituents described above may be optionally substituted with one or more substituents selected from the group consisting of hydroxyl groups; halogens; alkyl groups or alkenyl groups, aryl groups, alkoxy groups; alkyl groups or alkenyl groups, aryl groups, alkoxy groups comprising one or more heteroatoms of groups 14 to 16; silyl groups; alkylsilyl groups or alkoxysilyl groups; phosphine groups; phosphide groups; sulfonate groups; and sulfone groups, within the range of producing the same or similar effects as the desired effect.

[0207]

[0208] Furthermore, the fact that two adjacent substituents are connected to form an aliphatic or aromatic ring means that the atom(s) of the two substituents and the valence (atoms) to which the two substituents are bonded are connected to form a ring. Specifically, -NR9R 10 R9 and R 10Examples of these interconnected groups forming an aliphatic ring include piperidinyl groups, and -NR9R 10 R9 and R 10 Examples of groups connected to form an aromatic ring include pyrrolyl groups.

[0209]

[0210] In addition, group 4 transition metals include titanium (Ti), zirconium (Zr), hafnium (Hf), etc., but are not limited to these.

[0211]

[0212] For example, the first metallocene compound represented by the above chemical formula 1 is Cp 1 and Cp 2 As a non-crosslinked compound containing a ligand of, Cp 1 and Cp 2 The ligands of may be identical or different from each other, and are each cyclopentadiennyl, and C 1-10 One or more alkyl groups or one to three can be substituted.

[0213]

[0214] Also, the above Cp 1 and Cp 2 The ligand of can easily control characteristics such as the chemical structure, molecular weight, molecular weight distribution, mechanical properties, and transparency of the olefin polymer produced by adjusting the degree of steric hindrance effect according to, for example, the type of substituted functional group. Specifically, the above Cp 1 and Cp 2 The ligands of are R, respectively. a and R b It is replaced with, at this time, the above R a and R b are identical or different from each other, and independently, hydrogen, C 1-20 Alkyl, C 2-20 Alkoxyalkyl, C 7-40C comprising an arylalkyl, or one or more heteroatoms selected from the group consisting of N, O, and S. 2-12 It can be heteroaryl, and more specifically, C 1-10 Alkyl, C 2-10 Alkoxyalkyl, C 7-20 C comprising an arylalkyl, or one or more heteroatoms selected from the group consisting of N, O, and S. 4-12 It can be heteroaryl. However, R a and R b At least one of them is C 1-20 alkyl or C 7-20 It is an arylalkyl, and one of the others is C 2-20 It is an alkoxyalkyl. For example, R a One or more of them are C 1-20 alkyl or C 7-20 It is an arylalkyl of, and R a The remainder is hydrogen, and R b One of them is C 2-20 It is an alkoxyalkyl, and R b The remainder is hydrogen, or C 1-20 alkyl or C 7-20 It can be an arylalkyl.

[0215]

[0216] Also, the above Cp 1 and Cp 2 Between the ligands of M 1 Z 1 3-n This exists, M 1 Z 1 3-n can affect the storage stability of metal complexes. To ensure this effect more effectively, Z 1 Each independently is a halogen or C 1-20 It may be an alkyl group, and more specifically, it may be F, Cl, Br, or I independently. Also, the above M 1 It may be Ti, Zr or Hf; Zr or Hf; or Zr.

[0217]

[0218] Among the first transition metal compounds above, Cp in Chemical Formula 1 1 and Cp 2 are each an unsubstituted or substituted cyclopentadienyl group, and R a and R b Each independently hydrogen, C 1-10 Alkyl, C 2-10 Alkoxyalkyl, or C 7-20 It is an arylalkyl, but R a and R b At least one of them may be an alkyl group such as methyl or butyl, or an arylalkyl group such as phenylpropyl, and the remainder may be an alkoxyalkyl group such as a t-butoxyhexyl group, more specifically a -(CH2)n-OR substituent (wherein R is a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, and n is an integer from 2 to 4).

[0219]

[0220] The first metallocene compound represented by the above chemical formula 1 may be, for example, a compound represented by one of the following structural formulas, but is not limited thereto.

[0221]

[0222]

[0223] Meanwhile, the second metallocene compound comprises an aromatic ring compound containing thiophene as a different ligand and a base compound containing a group 14 or 15 atom, the different ligands are cross-linked by -T-, and has a structure in which M(X1)(X2) exists between the different ligands.

[0224]

[0225] More specifically, in the above chemical formula 2, M is Ti, Zr, or Hf, and more specifically, may be Ti.

[0226]

[0227] Also, R1 to R4 are each independently hydrogen, or C 1-20 It is an alkyl, and more specifically, it can be hydrogen or methyl.

[0228]

[0229] Also, R5 and R6 each independently C 1-10 It is alkyl, and more specifically, both R5 and R6 can be methyl.

[0230]

[0231] Also, Z is -NR7-, and the above R7 is C 1-10 Alkyl, more specifically C such as t-butyl 3-10 It can be a branched alkyl.

[0232]

[0233] Also, T is And, the above T1 is C or Si, and Y1 is C 1-20 Alkyl, C 1-20 Alkoxy, C 2-20 Alkoxyalkyl, C 6-20 Aril, C 7-30 Alkylaryl, C 7-30 Arylalkyl, C 6-20 Aryloxy, or C 7-30 It is aryloxyalkyl, and Y2 is C 2-20 Alkoxyalkyl, or C 7-30 It is an aryloxyalkyl, and more specifically, Y1 can be any one of a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, and Y2 is C 2-20 Alkoxyalkyl, or C 7-30 It is an aryloxyalkyl, and more specifically, Y2 may be any one of a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an iso-propoxymethyl group, an iso-propoxyethyl group, an iso-propoxyhexyl group, a tert-butoxymethyl group, a tert-butoxyethyl group, a tert-butoxyhexyl group, and a phenoxyhexyl group.

[0234]

[0235] Also, X1 and X2 are each independently halogen or C 1-20It is an alkyl, and more specifically, it can be chloro or methyl.

[0236]

[0237] For example, as the second metallocene compound, compounds represented by the following chemical formulas 2a to 2d may be exemplified, and among the compounds represented by the following chemical formulas 2a to 2d, two or more compounds of different structures are included.

[0238]

[0239] According to one embodiment of the present invention, as the second metallocene compound, a combination of two compounds represented by the following formula 2a and two compounds represented by the following formula 2b, or a combination of two compounds represented by the following formula 2a and two compounds represented by the following formula 2c, or a combination of two compounds represented by the following formula 2a and two compounds represented by the following formula 2d, or a combination of two compounds represented by the following formula 2b and two compounds represented by the following formula 2c, or a combination of two compounds represented by the following formula 2b and two compounds represented by the following formula 2d, or a combination of two compounds represented by the following formula 2c and two compounds represented by the following formula 2d may be used.

[0240]

[0241] In this way, by using a mixture of two or more compounds with different structures among the compounds represented by the following chemical formulas 2a to 2d as the second metallocene compound together with one first metallocene compound, it is possible to produce polyethylene with optimized density, low molecular weight ratio, SCB content, BOCD index, and BMI index.

[0242] [Chemical Formula 2a]

[0243]

[0244] [Chemical Formula 2b]

[0245]

[0246] [Chemical Formula 2c]

[0247]

[0248] [Chemical Formula 2d]

[0249]

[0250] In the above chemical formulas 2a to 2d, R1 to R7, M, X1, X2, T1, Y1, and Y2 are as previously defined.

[0251]

[0252] More specifically, in the second metallocene compound of the above formulas 2a to 2d, M is Ti, Zr, or Hf, more specifically Ti; and R1 to R4 are each independently hydrogen, or C 1-20 It is alkyl, more specifically hydrogen or methyl; R5 and R6 are each independently C 1-10 It is alkyl, more specifically, both R5 and R6 are methyl; and the above R7 is C 1-10 It is an alkyl, and more specifically, C such as t-butyl. 3-10 It is a branched alkyl; above, T1 is C or Si, and Y1 is C 1-20 Alkyl, C 1-20 Alkoxy, C 2-20 Alkoxyalkyl, C 6-20 Aril, C 7-30 Alkylaryl, C 7-30 Arylalkyl, C 6-20 Aryloxy, or C 7-30 It is aryloxyalkyl, and Y2 is C 2-20 Alkoxyalkyl, or C 7-30 It is an aryloxyalkyl, more specifically, Y1 is any one of a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, and Y2 is C 2-20 Alkoxyalkyl, or C 7-30It is an aryloxyalkyl, more specifically, Y2 is any one of a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an iso-propoxymethyl group, an iso-propoxyethyl group, an iso-propoxyhexyl group, a tert-butoxymethyl group, a tert-butoxyethyl group, a tert-butoxyhexyl group, and a phenoxyhexyl group, and X1 and X2 are each independently a halogen or C 1-20 It may be a compound that is alkyl, and more specifically, chloro or methyl.

[0253]

[0254] More specifically, specific examples of the second metallocene compound may include compounds having the following structures, but are not limited thereto:

[0255] , ,

[0256] , ,

[0257] , .

[0258]

[0259] Meanwhile, the first and second metallocene compounds in the catalyst composition may be included in a molar ratio of 1:0.3 to 1:3, and more specifically, in a molar ratio of 1:0.3 or higher, or 1:0.4 or higher, or 1:0.5 or higher, and in a molar ratio of 1:3 or lower, or 1:2 or lower.

[0260]

[0261] In addition, two types of second metallocene compounds of different structures in the catalyst composition may be included in a molar ratio of 1:0.1 to 1:1, and more specifically, in a molar ratio of 1:0.1 or higher, or 1:0.2 or higher, or 1:0.4 or higher, and in a molar ratio of 1:1 or lower, or 1:0.8 or lower.

[0262]

[0263] Meanwhile, the catalyst composition may further include a carrier, in which case the first and second metallocene compounds are used in a state supported on the carrier.

[0264]

[0265] Specific examples of the above carriers include silica, alumina, magnesia, silica-alumina, silica-magnesia, etc., and these may further include oxide, carbonate, sulfate, and nitrate components such as Na2O, K2CO3, BaSO4, and Mg(NO3)2.

[0266]

[0267] In addition, the catalyst composition may further include a co-catalyst to improve high activity and process stability, and the co-catalyst may be, more specifically, an alkylaluminoxan-based co-catalyst such as methylaluminoxan, ethylaluminoxan, isobutylaluminoxan, or butylaluminoxan.

[0268]

[0269] Meanwhile, polyethylene according to one embodiment of the present invention is produced by polymerizing ethylene using the catalyst composition described above, and the polymerization process can be carried out as a monomodal (or unimodal) polymerization process in which a polymerization reaction is carried out under single polymerization reaction conditions using a single catalyst in a single reactor, and more specifically, it can be carried out in a single loop-type slurry reactor in the presence of the hybrid supported catalyst described above.

[0270]

[0271] For example, the polymerization process described above can be carried out by additionally adding an alpha-olefin copolymer along with ethylene.

[0272]

[0273] The above alpha-olefin may be one or more selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and mixtures thereof. Preferably, 1-hexene or 1-butene may be used as the alpha-olefin, and more specifically, 1-hexene may be used.

[0274]

[0275] For example, in the polymerization process described above, the alpha-olefin described above may be introduced in an amount of 12% by weight or less relative to the amount of ethylene introduced. Specifically, the alpha-olefin may be introduced in an amount of 10% by weight or less, or 8% by weight or less, or 7.5% by weight or less, or 7% by weight or less, or 6.5% by weight or less, or 6% by weight or less, or 5.8% by weight or less, or 5.5% by weight or less, but is not limited thereto. In addition, the alpha-olefin may be introduced in an amount of 0.1% by weight or more, or 0.3% by weight or more, or 0.5% by weight or more, or 0.7% by weight or more, or 0.85% by weight or more, or 0.9% by weight or more, or 1.0% by weight or more, or 1.2% by weight or more, or 1.4% by weight or more, or 1.6% by weight or more, but is not limited thereto.

[0276]

[0277] In addition, the polyethylene in the present invention can be manufactured by introducing hydrogen gas in the presence of the catalyst composition described above.

[0278]

[0279] Specifically, the polymerization step can be performed by introducing hydrogen gas at a concentration of about 150 ppm to about 480 ppm based on ethylene content. More specifically, hydrogen gas can be introduced at a concentration of about 160 ppm or more, or about 180 ppm or more, or about 200 ppm or more, and at the same time, at a concentration of about 460 ppm or less, or about 450 ppm or less, or about 445 ppm or less, or about 440 ppm or less, or about 435 ppm or less, or about 430 ppm or less.

[0280]

[0281] At this time, the polymerization temperature may be 25 ℃ to 500 ℃, and preferably 25 ℃ to 200 ℃, or 60 ℃ to 120 ℃, or 70 ℃ to 100 ℃, or 72 ℃ to 95 ℃, or 75 ℃ to 90 ℃, or 78 ℃ to 88 ℃, or 80 ℃ to 85 ℃.

[0282]

[0283] In addition, the polymerization pressure may be 1 Kgf / ㎠ to 100 Kgf / ㎠, preferably 1 Kgf / ㎠ to 70 Kgf / ㎠, or 2 Kgf / ㎠ to 50 Kgf / ㎠, or 5 Kgf / ㎠ to 50 Kgf / ㎠, or 8 Kgf / ㎠ to 45 Kgf / ㎠, or 10 Kgf / ㎠ to 42 Kgf / ㎠.

[0284]

[0285] Meanwhile, according to another embodiment of the invention, a polyethylene composition is provided comprising virgin polyethylene (or Booster PE) and recycled polyethylene (PCW PE, Post consumer waste polyethylene), wherein the virgin polyethylene is the polyethylene of the above-described embodiment or a mixture thereof.

[0286]

[0287] In particular, the polyethylene composition according to the present invention uses polyethylene in which the ratio of the low molecular weight region, SCB content, BOCD index, and BMI index are all optimized by optimizing the molecular structure along with the density as described above. This improves environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties when combined with recycled polyethylene, thereby ensuring excellent flexural modulus and drop impact strength comparable to that of virgin resin even when combined with recycled polyethylene.

[0288]

[0289] Accordingly, the polyethylene composition of the present invention can produce a molded article having high mechanical properties along with excellent environmental stress cracking resistance (ESCR) even when combined with recycled polyethylene resin by using the polyethylene of the above-described embodiment.

[0290]

[0291] For example, in a polyethylene composition, the virgin polyethylene may be included in an amount of 5% or more by weight or from 5% to 85% by weight based on the total weight of the composition, and the recycled polyethylene may be included in an amount of 15% or more by weight or from 15% to 95% by weight based on the total weight of the composition. In particular, to enhance the carbon dioxide emission suppression effect of the polyethylene composition and to reduce costs, the content of the virgin polyethylene may be 85% or less by weight, or 50% or less by weight, or 30% or less by weight, and the content of the recycled polyethylene resin (PCW PE) may be 15% or more by weight, or 20% or more by weight, or 30% or more by weight. In addition, in terms of improving the flexural modulus and drop impact strength of the polyethylene composition and achieving physical properties equivalent to those of virgin resin, the content of the virgin polyethylene (Booster PE) may be 5 weight% or more, or 7 weight% or more, or 10 weight% or more, and the content of the recycled polyethylene resin (PCW PE) may be 95 weight% or less, or 80 weight% or less, or 60 weight% or less.

[0292]

[0293] Here, the total sum of the new polyethylene content and the recycled polyethylene content does not exceed 100%.

[0294]

[0295] Meanwhile, the above-described novel polyethylene may additionally include high-density polyethylene together with the polyethylene of the above-described embodiment.

[0296]

[0297] For example, the high-density polyethylene among the above-mentioned new polyethylene may be included in an amount of 80% by weight or less, or 0 to 80% by weight or less, based on the total weight of the entire composition. In particular, to enhance the carbon dioxide emission suppression effect of the polyethylene composition and to reduce costs, the content of high-density polyethylene among the above-mentioned new polyethylene may be 80% by weight or less, 70% by weight or less, or 60% by weight or less. The content of high-density polyethylene among the above-mentioned new polyethylene may be 5% by weight or more, 20% by weight or more, or 40% by weight or more.

[0298]

[0299] Specifically, the high-density polyethylene additionally included as the novel polyethylene has a density (ASTM D 1505, 23 °C) of 0.955 g / cm³ 3 Above or 0.955 g / cm³ 3 Up to 0.965 g / cm³ 3 It may be. More specifically, the density of the high-density polyethylene is 0.956 g / cm³ 3 Above, or 0.957 g / cm³ 3 Above, or 0.958 g / cm³ 3 It may be greater than 0.963 g / cm³ 3 Less than or equal to 0.962 g / cm³ 3 Less than or equal to 0.961 g / cm³ 3 Less than or equal to 0.960 g / cm³ 3 It may be less than.

[0300]

[0301] In addition, the above high-density polyethylene has a melt index (MI 2.16 , 190 o C (measured under a 2.16 kg load) may be 0.1 g / 10 min to 0.5 g / 10 min.

[0302]

[0303] In addition, the above high-density polyethylene may have an environmental stress cracking resistance (ESCR) of 200 hours or more or 200 to 400 hours as measured according to ASTM D 1693 (Condition B, F50, Igepal 10%).

[0304]

[0305] Meanwhile, the above recycled polyethylene (PCW PE) has a density (ASTM D 1505, 23 ℃) of 0.940 g / cm³ 3 Up to 0.960 g / cm³ 3 It can be represented by such characteristics. More specifically, the density of the recycled polyethylene (PCW PE) (ASTM D 1505, 23 ℃) is 0.943 g / cm³. 3 Above, or 0.945 g / cm³ 3 Above, or 0.948 g / cm³ 3 Above, 0.950 g / cm³ 3 It may be greater than 0.958 g / cm³ 3 Less than or equal to 0.956 g / cm³ 3 Less than or equal to 0.955 g / cm³ 3 Less than or equal to 0.953 g / cm³ 3 It may be less than.

[0306]

[0307] In addition, the above recycled polyethylene (PCW PE) has a melt index (MI 2.16 , 190 o C (measured under a 2.16 kg load) may be 0.1 g / 10 min to 0.7 g / 10 min.

[0308]

[0309] In addition, the above recycled polyethylene (PCW PE) may have an environmental stress cracking resistance (ESCR) of 20 to 60 hours as measured according to ASTM D 1693 (Condition B, F50, Igepal 10%).

[0310]

[0311] Meanwhile, the polyethylene composition according to the present invention can secure excellent flexural modulus and drop impact strength comparable to that of virgin resin while increasing the recycled polyethylene content.

[0312]

[0313] Specifically, the polyethylene composition has an environmental stress cracking resistance (ESCR) of 200 hours or more, measured according to ASTM D 1693 (Condition B, F50, Igepal 10%), and a density (ASTM D 1505, 23 ℃) of 0.945 g / cm³ 3 Above or 0.945 to 0.960 g / cm³ 3 It could be.

[0314]

[0315] For example, the method for measuring the environmental stress cracking resistance (ESCR) of the above polyethylene composition is as described in Test Example 2 below. However, the method for measuring the environmental stress cracking resistance (ESCR) of the above polyethylene composition is not limited thereto and may be measured by other methods known in the art to which the present invention belongs.

[0316]

[0317] In addition, the polyethylene composition may have an SCB content of 1.8 (pieces / 1000C) or more or 1.8 to 5 (pieces / 1000C), a BOCD index (Broad Orthogonal Co-monomer Distribution Index) of 0.7 or more or 0.7 to 1.8, and a BMI index (bimodality index) of 1.5 or more or 1.5 to 2.5.

[0318]

[0319] In addition, the above polyethylene composition has a melt index (MI) measured at 190°C and a 2.16 kg load according to ASTM D 1238. 2.16 ) may be 0.2 g / 10min to 0.5 g / 10min, or 0.25 g / 10min to 0.33 g / 10min.

[0320]

[0321] In addition, the polyethylene composition may have a weight-average molecular weight of 144,000 g / mol to 151,500 g / mol and a molecular weight distribution (Mw / Mn) of 15.1 to 16.5.

[0322]

[0323] At this time, the density, ESCR time, SCB content, BOCD index, BMI index, and melt index (MI) of the polyethylene composition 2.16 The measurement methods for weight-average molecular weight, molecular weight distribution (Mw / Mn), etc., are as described above with respect to polyethylene, and can be used to measure polyethylene compositions instead of polyethylene using these methods, and specific details are omitted.

[0324]

[0325] In addition, the above polyethylene composition has a flexural modulus of 13,500 kgf / cm² as measured by the ASTM D 790 method. 2 or greater than or equal to 13,500 kgf / cm² 2 Up to 17,000 kgf / cm² 2It may be. Preferably, the flexural modulus of the polyethylene composition is 13,700 kg / cm² 2 Above, or 13,800 kg / cm² 2 Above, or 13,900 kg / cm² 2 Above, or 14,000 kg / cm² 2 or more than 14,200 kg / cm² 2 The above may be the case. For example, the method for measuring the flexural modulus is as described in Test Example 2 below. However, the method for measuring the flexural modulus is not limited thereto and may be measured by other methods known in the technical field to which the present invention belongs.

[0326]

[0327] Preferred embodiments are presented below to aid in understanding the present invention. However, the following embodiments are provided merely to facilitate a better understanding of the invention and do not limit the scope of the invention.

[0328]

[0329] [Example]

[0330] Manufacture of Polyethylene

[0331] Example 1-1

[0332] High-density new polyethylene was manufactured through a single slurry polymerization process as follows.

[0333]

[0334] First, 25 kg / h of isobutane and 30 kg / h of ethylene were injected into a single slurry loop reactor, along with hydrogen at a flow rate of 390 ppm. Subsequently, a catalyst (molar ratio of first metallocene compound (1), second metallocene compound (2), and second metallocene compound (3) = 1:0.41:0.2) in which the first metallocene compound (1), second metallocene compound (2), and second metallocene compound (3) were hybrid-supported on a silica carrier (Grace Davison, SP2212) and a comonomer (1-hexene) were injected. The comonomer used here was 1-hexene, and the input amount was 2.7 wt% relative to the ethylene input amount. At this time, the reactor was maintained between 80 and 85 ℃, and the pressure was 42 kg / cm². 3 The copolymerization process was carried out by maintaining the solvent, and subsequently, the high-density virgin polyethylene (HDPE, Virgin polyethylene) of Example 1-1 was produced in powder form through a solvent removal facility and a dryer.

[0335] (1)

[0336] (2) (3).

[0337]

[0338] Examples 1-2

[0339] The same polymerization process as in Example 1-1 was performed, but with hydrogen changed to 415 ppm and coconomer(1-hexene) to 2.4 wt% to homopolymerize, thereby producing the high-density new polyethylene of Example 1-2.

[0340]

[0341] Examples 1-3

[0342] The same polymerization process as in Example 1-1 was performed, but with the hydrogen content changed to 200 ppm and the amount of Commonomer (1-hexene) to 3.1 wt% to homopolymerize, thereby producing the high-density new polyethylene of Example 1-3.

[0343]

[0344] Examples 1-4

[0345] The same polymerization process as in Example 1-1 was performed, but with hydrogen changed to 245 ppm and coconomer(1-hexene) to 5.4 wt% to homopolymerize, thereby producing the high-density new polyethylene of Example 1-4.

[0346]

[0347] Examples 1-5

[0348] The same polymerization process as in Example 1-1 was performed, but with hydrogen changed to 430 ppm and coconomer(1-hexene) to 2.3 wt% to homopolymerize, thereby producing the high-density new polyethylene of Example 1-5.

[0349]

[0350] Examples 1-6

[0351] The same polymerization process as in Example 1-1 was performed, but with hydrogen changed to 270 ppm and coconomer(1-hexene) to 1.6 wt% to homopolymerize, thereby producing the high-density new polyethylene of Example 1-6.

[0352]

[0353] Comparative Example 1-1

[0354] A commercially available high-density polyethylene (HDPE) product manufactured using a metallocene catalyst (LG Chem product, product name SP4701) was prepared as the high-density new polyethylene of Comparative Example 1-1.

[0355]

[0356] Comparative Example 1-2

[0357] For a commercially available high-density polyethylene (HDPE) product (LG Chem product, product name SP4701) manufactured using a metallocene catalyst, a density of 0.957 g / cm³ 3 , Melt Index (MI 2.16A high-density polyethylene product (LG Chem’s ME8000 product) with a density of 8 g / 10 min was dry-blended to prepare the high-density new polyethylene of Comparative Example 1-2.

[0358]

[0359] Comparative Examples 1-3

[0360] The same polymerization process as in Example 1-1 was performed, except that a catalyst (molar ratio of the first metallocene compound to the second metallocene compound = 2:1) in which the following first metallocene compound (1) and second metallocene compound (2) were hybridized and supported on a silica carrier (Grace Davison, SP2212) was added, and after homopolymerization was performed by changing the hydrogen content to 200 ppm and the coonomer(1-hexene) content to 2.2 wt%, a density of 0.957 g / cm³ was obtained. 3 , Melt Index (MI 2.16 A high-density polyethylene product (LG Chem’s ME8000 product) with a density of 8 g / 10 min was dry-blended to prepare the high-density new polyethylene of Comparative Examples 1-3.

[0361] (1) (2).

[0362]

[0363] Comparative Examples 1-4

[0364] The same polymerization process as in Comparative Example 1-3 was performed, but with the hydrogen content changed to 220 ppm and the coconomer (1-hexene) content to 1.5 wt% to homopolymerize, thereby producing the high-density new polyethylene of Comparative Example 1-4.

[0365]

[0366] Comparative Examples 1-5

[0367] A commercially available high-density polyethylene (HDPE) product (product of Q Chem, product name TR571) was prepared as the high-density new polyethylene of Comparative Example 1-5.

[0368]

[0369] Comparative Examples 1-6

[0370] The same polymerization process as in Comparative Example 1-3 was performed, but with the hydrogen content changed to 700 ppm and the coconomer (1-hexene) content to 1.8 wt% to homopolymerize, thereby producing the high-density new polyethylene of Comparative Example 1-6.

[0371]

[0372] Comparative Examples 1-7

[0373] A polyolefin elastomer product (LG Chem product, product name LC170) was prepared as the high-density new polyethylene of Comparative Example 1-7.

[0374]

[0375] <Test Example 1: Evaluation of Physical Properties of Polyethylene>

[0376] The physical properties of the polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7 were evaluated in the following manner, and the measurement results are shown in Table 1 below.

[0377]

[0378] (1) Melt index

[0379] 190 according to the American Society for Testing Materials standard ASTM D 1238 (Condition E) o Each melt index (MI) under C with loads of 2.16 kg and 21.6 kg 2.16 ) and Melt Index (MI 21.6 ) was measured and expressed as the weight (g) of the polymer that melted out over 10 minutes.

[0380]

[0381] Specifically, for the polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-4, 1-6, and 1-7, the respective melt index (MI) measured under a load of 2.16 kg 2.16 The respective melt indices (MI) measured under a load of 21.6 kg for the polyethylene of Comparative Examples 1-5 are shown in Table 1 below. 21.6) is shown in Table 1 below.

[0382]

[0383] (2) Density

[0384] Density of polyethylene (g / cm³) according to the American Society for Testing and Materials (ASTM) D 1505 standard 3 ) was measured.

[0385]

[0386] (3) Weight-average molecular weight (Mw, g / mol) and molecular weight distribution (PDI, polydispersity index, Mw / Mn)

[0387] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polyethylene were measured using gel permeation chromatography (GPC, manufactured by Polymer Char), and the molecular weight distribution (PDI, Mw / Mn) was calculated by dividing the weight-average molecular weight by the number-average molecular weight.

[0388]

[0389] Specifically, a Polymer Char GPC-IR instrument was used as the gel permeation chromatography (GPC) device, and a Polymer Laboratories PLgel MIX-B 300 mm long column was used. The measurement temperature was 160 ℃, 1,2,4-trichlorobenzene was used as the solvent, and the flow rate was 1 mL / min. Polyethylene samples according to Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7 were each pretreated by dissolving them in trichlorobenzene (1,2,4-trichlorobenzene) containing 0.0125% butylated hydroxytoluene (BHT) at 160 ℃ for 2 hours using a GPC analyzer (GPC-IR), prepared to a concentration of 10 mg / 10 mL, and supplied in an amount of 200 μL. The values ​​of Mw and Mn were derived using a calibration curve formed using polystyrene standard specimens. Nine types of polystyrene standard specimens with weight-average molecular weights were used: 2000 g / mol, 10000 g / mol, 30000 g / mol, 70000 g / mol, 200000 g / mol, 700000 g / mol, 2000000 g / mol, 4000000 g / mol, and 10000000 g / mol.

[0390]

[0391] (4) LogMw≤4.5 (low molecular weight region) and LogMw≥5.5 (high molecular weight region) content

[0392] For the polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7, gel permeation chromatography (GPC, manufactured by Polymer Char) was used in the manner described above to analyze the y-axis (dw / dlogMw) and x-axis (logMw) curves. The regions where the Log MW value was 4.5 or less (LogMw≤4.5) and the regions where the Log MW value was 5.5 or more (LogMw≥5.5) were expressed as percentiles.

[0393]

[0394] (5) SCB content

[0395] SCB (units / 1000C) was measured for the polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7 at 160 ℃ using GPC-IR equipment.

[0396]

[0397] Specifically, the sample was pretreated by melting it in 1,2,4-Trichlorobenzene containing 0.0125% BHT at 160 ℃ for 2 hours, and then measured at 160 ℃ using IR4 and IR6 connected to a high-temperature GPC (GPC-IR).

[0398]

[0399] (6) BOCD index

[0400] As described above, the SCB (Short Chain branch) content was measured at the left and right boundaries of the middle 60% excluding the left and right ends relative to the total area of ​​the GPC curve graph, which is a GPC curve graph with the weight-average molecular weight (Mw) of the polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7 measured through GPC analysis, i.e., with the x-axis being log MW and the y-axis being dw / dlogMw, and the BOCD was measured as shown in Equation 1 below.

[0401] [Equation 1]

[0402] .

[0403] At this time, the SCB content in the high molecular weight region and the SCB content in the low molecular weight region refer to the SCB content value at logMw corresponding to 20% of the high molecular weight region and the low molecular weight region, respectively, and the high molecular weight log Mw and low molecular weight log Mw values ​​are the logMw values ​​corresponding to 20% of the high molecular weight region and the low molecular weight region, respectively, relative to the total area of ​​the y-axis (dw / dlogMw) and x-axis (logMw) curves through GPC analysis.

[0404]

[0405] (7) BMI index

[0406] As described above, the BOCD was measured by separating the peaks (peak A, peak B) forming the low molecular weight fraction and the high molecular weight fraction from the GPC curve graph of the weight-average molecular weight (Mw) of the polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7 measured through GPC analysis, i.e., the GPC curve graph where the x-axis is log MW and the y-axis is dw / dlogMw, and measuring each peak as shown in Equation 2 below.

[0407] [Equation 2]

[0408]

[0409] In the above Equation 2,

[0410] Peaks A and B are the peaks (peak A, peak B) of the low molecular weight fraction and the high molecular weight fraction, respectively, when the peaks (peak A, peak B) forming the low molecular weight fraction and the high molecular weight fraction are separated using peak deconvolution (Gaussian Probability Function) on a GPC curve graph for polyethylene where the x-axis is log MW and the y-axis is dw / dlogMw.

[0411] logMw(peak A) and logMw(peak B) are the logMw values ​​at the maximum dw / dlogMw for each peak, and

[0412] AR(peak A) and AR(peak B) are the area ratio (AR) of each peak relative to the total area of ​​the derived peaks A and B.

[0413]

[0414] (8) Flexural modulus

[0415] Flexural modulus (kgf / cm²) for polyethylene of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-7 according to the ASTM D 790 method 2 ) was measured and shown in Table 1 below.

[0416]

[0417] MI (g / 10 min) Density (g / cm²) 3 )Mw(g / mol)PDI(Mw / Mn)LogMw≥5.5(%)LogMw≤4.5(%)SCB(pcs / 1000C)BOCDBMIFlexural Modulus(kgf / cm 2Example 1-10.51 (2.16 kg load) 0.94613230024.912.954.74.64.292.7312,000 Example 1-20.55 (2.16 kg load) 0.94813070024.913.254.73.73.332.7312,200 Example 1-30.56 (2.16 kg load) 0.94613680024.31354.44.54.502.7611,000 Example 1-40.55 (2.16 kg load) 0.94614930024.314.657.35.26.172.5510,900 Example 1-5 1.08 (2.16 kg load) 0.95 0 116 800 23.5 10.65 64.13.27 2.7 12,200 Example 1-6 0.22 (2.16 kg load) 0.95 0 17 8300 24.6 16.85 0.53 2.30 2.67 12,100 Comparative Example 1-10.16 (2.16 kg load) 0.94 7 210 300 21.3 18.83 9.12.30 90 1.88 12,300 Comparative Example 1-20.29 (2.16 kg load) 0.94 8 16 7 800 15.0 14.74 1.21.8 0.86 1.66 12,400 Comparative Example 1-30.55 (2.16 kg Load) 0.946 137 800 15.1 11.8 48.3 4.1 2.1 52.0 8 11,700 Comparative Example 1-4 0.5 1 (2.16 kg Load) 0.947 143 600 16.8 13 47.4 2.5 1.6 82.0 7 11,800 Comparative Example 1-5 2.6 (21.6 kg Load) 0.95 131 3500 29.0 22.3 29.7 0.7 0.4 0 1.6 12,500 Comparative Example 1-6 21 0 (2.16 kg Load) 0.95 228 300 3.0 0.1 72.2 3.0 2.2 0 1.5 4 12,500 Comparative Example 1-7 1.0 (2.16 kg Load)0.870989003.73.318.845.61.701.56140

[0418]

[0419] In Table 1 above, the melt index measurements are the respective melt index (MI) measured under a load of 2.16 kg for the polyethylenes of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-4, 1-6, and 1-7. 2.16) was shown, and for the polyethylene of Comparative Examples 1-5, the melt index (MI) measured under a load of 21.6 kg was 21.6 It represented ).

[0420]

[0421] <Preparation of Polyethylene Compound (PCR Compound) Mixed with Recycled Polyethylene (PCW PE)>

[0422] Example 2-1

[0423] 10 wt% of the polyethylene prepared in Example 1-1 and 60 wt% of high-density polyethylene (product of Lotte Chemical, product name 6200B) were used as virgin polyethylene, and after dry blending with 30 wt% of recycled polyethylene (PCW PE, Post consumer waste polyethylene), the polyethylene composition (PCR Compound) of Example 2-1 was prepared by extruding through a twin screw extruder.

[0424]

[0425] Specifically, the high-density polyethylene is a commercially available Booster Grade high-density polyethylene (HDPE) product for PCR manufactured using a Ziegler-Natta catalyst (Z / N, Zeigier-Natta catalyst) (product of Lotte Chemical, product name 6200B).

[0426]

[0427] In addition, the above-mentioned recycled polyethylene (BSN Baeksan natural color product of Baeksan Plastic Co., Ltd.) has a melt index MI 2.16 (190 according to ASTM D 1238 (Condition E) o (Measured under a 2.16 kg load at C) is at the level of 0.15–0.2 g / 10 min, and the density (measured according to ASTM D 1505 standard) is 0.951–0.953 g / cm³ 3, ESCR (measured the time to F50 (50% destruction) under 50°C conditions using 10% Igepal CO-630 Solution according to ASTM D 1693) is at the 40–50 hour level.

[0428]

[0429] Examples 2-2 to 2-6

[0430] Polyethylene resin compositions (PCR Compounds) were prepared in the same manner as in Example 2-1, but using the polyethylene of Examples 1-2 to 1-6 instead of the polyethylene of Example 1-1, and mixing recycled polyethylene (PCW PE) in the same manner as in Example 2-1 to prepare the polyethylene compositions (PCR Compounds) of Examples 2-2 to 2-6.

[0431]

[0432] Comparative Examples 2-1 to 2-7

[0433] Polyethylene resin compositions (PCR Compounds) were prepared in the same manner as in Example 2-1, but using the polyethylene of Comparative Examples 1-1 to 1-7 instead of the polyethylene of Example 1-1, and mixing recycled polyethylene (PCW PE) in the same manner as in Example 2-1 to prepare the polyethylene compositions (PCR Compounds) of Comparative Examples 2-1 to 2-7.

[0434]

[0435] <Test Example 2: Evaluation of Physical Properties of Polyethylene Composition>

[0436] For the polyethylene compositions (PCR Compound) of Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-7 prepared as described above, the physical properties of the polyethylene compositions were evaluated in the same manner as described above, except that ESCR measurements were performed as follows without evaluating the region where the Log MW value was 4.5 or lower (LogMw≤4.5) and the region where the Log MW value was 5.5 or higher (LogMw≥5.5) in the previous evaluation of the physical properties of polyethylene, and the measurement results are shown in Table 2 below.

[0437]

[0438] (9) ESCR measurement

[0439] According to the method of ASTM D 1693-07, the time to F50 (50% destruction) for a polyethylene composition (PCR Compound) was measured using 10% Igepal CO-630 Solution at a temperature of 50 ℃ under Condition B, and is expressed as ESCR (hr) in Table 2 below.

[0440]

[0441] Polyethylene content (wt%) High-density polyethylene content (wt%) Recycled polyethylene resin (PCW PE) content (wt%) MI (2.16 kg load, g / 10 min) Density (g / cm²) 3 )SCB(unit / 1000C)BOCDBMIESCR(hr)Flexural Modulus(kgf / cm) 2Example 2-1 1060300.270.9522.90.91.5624013,900 Example 2-2 1060300.280.9532.60.721.5623014,000 Example 2-3 1060300.280.9533.20.971.7324013,900 Example 2-4 1060300.250.9523.51.11.6630013,900 Example 2-5 1060300.290.9532.40.961.6921014,200 Example 2-61060300.250.9541.80.891.6924014,300 Comparative Example 2-11060300.260.9521.80.461.3914013,800 Comparative Example 2-21060300.250.9531.30.411.3615013,800 Comparative Example 2-31060300.260.9522.30.71.4219013,700 Comparative Example 2-41060300.270.95320.561.418013,700 Comparative Example 2-51060300.210.9540.80.381.518013,500 Comparative Example 2-61060301.040.9541.90.661.446013,900 Comparative Example 2-71060300.290.9509.61.31.4225012,900

[0442]

[0443] Referring to Table 2 above, it can be seen that when using the polyethylene of Examples 1-1 to 1-6, in which the molecular structure along with density is optimized according to the present invention to optimize the ratio of the low molecular weight region, SCB content, BOCD index, and BMI index, excellent mechanical properties are maintained and a high flexural modulus is approximated by that of virgin polyethylene even when combined with recycled polyethylene (PCW PE), while at the same time, environmental stress cracking resistance (ESCR) can be significantly improved.

Claims

1. Density is 0.935 g / cm³ 3 That is all, In a GPC curve graph where the x-axis is log MW and the y-axis is dw / dlogMw, the integral value in the region where the Log MW value is 4.5 or less is between 30% and 70% of the total integral value, and The SCB content is 2.0 (pieces / 1000C) or more and 8.0 (pieces / 1000C) or less, and The BOCD (Broad Orthogonal Co-monomer Distribution Index) is 2.2 or higher, and Those with a BMI (bimodality index) of 2.0 or higher Polyethylene.

2. In Paragraph 1, The above polyethylene is an ethylene homopolymer or an ethylene / alpha-olefin copolymer, Polyethylene.

3. In Paragraph 2, The above alpha-olefin is one or more selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, and mixtures thereof. Polyethylene.

4. In Paragraph 1, The above polyethylene is such that, in a GPC curve graph where the x-axis is log MW and the y-axis is dw / dlogMw, the integral value in the region where the Log MW value is 5.5 or higher is 5% to 20% of the total integral value. Polyethylene.

5. In Paragraph 1, The above polyethylene has a molecular weight distribution (Mw / Mn) of 20 or more, Polyethylene.

6. In Paragraph 1, The above polyethylene has a weight-average molecular weight of 100,000 g / mol or more, Polyethylene.

7. In Paragraph 1, The above polyethylene has a melt index (MI) measured at 190°C and a 2.16 kg load according to ASTM D 1238. 2.16 ) having 0.1 g / 10 min to 1.2 g / 10 min, Polyethylene.

8. A polyethylene composition comprising virgin polyethylene and recycled polyethylene (PCW PE, Post consumer waste polyethylene), The above-mentioned novel polyethylene is polyethylene or a mixture thereof according to any one of claims 1 to 7, Polyethylene composition.

9. In Paragraph 8, The above-mentioned novel polyethylene is included in an amount of 5% by weight or more based on the total weight of the entire composition, and The above recycled polyethylene is included in an amount of 15 weight percent or more based on the total weight of the entire composition, Polyethylene composition.

10. In Paragraph 8, The above-mentioned novel polyethylene further comprises high-density polyethylene, Polyethylene composition.

11. In Paragraph 8, The above recycled polyethylene has a density of 0.940 g / cm³ 3 Up to 0.960 g / cm³ 3 person, Polyethylene composition.

12. In Paragraph 8, The above recycled polyethylene has a melt index (MI) measured at 190°C and a 2.16 kg load according to ASTM D 1238. 2.16 ) having 0.1 g / 10 min to 0.7 g / 10 min, Polyethylene composition.

13. In Paragraph 8, The above polyethylene composition is, Environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) is 200 hours or more, and Density is 0.945 g / cm³ 3 Lee Sang-in, Polyethylene composition.

14. In Paragraph 8, The above polyethylene composition is, The SCB content is 1.8 (pieces / 1000C) or higher, and The BOCD (Broad Orthogonal Co-monomer Distribution Index) is 0.7 or higher, and Those with a BMI (bimodality index) of 1.5 or higher Polyethylene composition.

15. In Paragraph 8, The above polyethylene composition has a melt index (MI) measured at 190°C and a 2.16 kg load according to ASTM D 1238. 2.16 ) having 0.2 g / 10 min to 0.5 g / 10 min, Polyethylene composition.

16. In Paragraph 8, The flexural modulus measured by the ASTM D 790 method is 13,500 kg / cm 2 Lee Sang-in, Polyethylene composition.

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