Polyethylene and composition comprising same

Abstract

The present invention provides polyethylene having improved processability and resistance to environmental stress cracking as well as retaining excellent 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. 10-2024-0133313 filed September 30, 2024 and Korean Patent Application No. 10-2025-0141600 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] The present invention relates to polyethylene that improves processability and environmental stress crack resistance while maintaining excellent mechanical properties when combined with recycled polyethylene, and a polyethylene composition containing the same.

[0004]

[0005] The demand for polyethylene resin is steadily increasing and it is being used in various applications.

[0006] 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.

[0007] 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, methods have been attempted to include a certain level of virgin resin in compositions containing recycled resin. However, this requires an excessive amount of virgin resin to minimize the degradation of mechanical properties, and issues regarding the deterioration of key properties, such as environmental stress cracking resistance (ESCR), remain unresolved. Furthermore, this problem becomes more severe as the number of processing cycles increases.

[0008] In addition, in the case of polyethylene resin products using recycled resin, there is a problem in that it is difficult to satisfy both mechanical properties and processability due to a trade-off relationship.

[0009] Accordingly, there is an urgent need for research and development of polyethylene with improved environmental stress crack resistance and excellent mechanical properties as a virgin resin to be blended with such recycled resin.

[0010]

[0011] The present invention aims to provide polyethylene that improves processability and resistance to environmental stress cracking while maintaining excellent mechanical properties when combined with recycled polyethylene, and a polyethylene composition containing the same.

[0012]

[0013] According to one embodiment of the present invention,

[0014] Provides a polyethylene that satisfies the following conditions (1) to (2):

[0015] (1) Density of 0.940 g / cm³ measured according to ASTM D 1505, 23 ℃ 2 more;

[0016] (2) SCI (Stress Crack Index) represented by Equation 1 is 300 or higher;

[0017] [Equation 1]

[0018] SCI = 1,000 * ESCR / Mw

[0019] In Equation 1,

[0020] ESCR is environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) (unit: hours),

[0021] Mw is the weight-average molecular weight (unit: g / mol) measured by GPC.

[0022]

[0023] In addition, according to one embodiment of the present 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 comprises the polyethylene described above.

[0024]

[0025] According to the present invention, by optimizing the molecular structure along with density, it is possible to provide polyethylene with improved processability and resistance to environmental stress cracking while maintaining excellent mechanical properties when combined with recycled polyethylene.

[0026]

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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%.

[0032]

[0033] 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.

[0034]

[0035] The present invention will be described in more detail below.

[0036]

[0037] According to one embodiment of the invention, polyethylene with an optimized molecular structure and density is provided so that it can improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties even when combined with recycled polyethylene.

[0038]

[0039] Specifically, the polyethylene of the present invention has a density of 0.940 g / cm³ as measured according to ASTM D 1505, 23 ℃. 2 This is the case, and the SCI (Stress Crack Index) represented by Equation 1 is 300 or higher.

[0040] [Equation 1]

[0041] SCI = 1,000 * ESCR / Mw

[0042] In Equation 1,

[0043] ESCR is environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) (unit: hours),

[0044] Mw is the weight-average molecular weight (unit: g / mol) measured by GPC.

[0045]

[0046] The polyethylene of the present invention will be described in more detail below.

[0047]

[0048] Specifically, the polyethylene according to one embodiment of the present invention may be an ethylene homopolymer or an ethylene / alpha-olefin copolymer.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053]

[0054] Polyethylene according to one embodiment of the present invention has a density of 0.940 g / cm³ as measured according to ASTM D 1505, 23 ℃. 3 Satisfies the ideal.

[0055] More specifically, the density of the polyethylene is 0.940 g / cm³ 3 Above, or 0.941 g / cm³ 3 Above, or 0.942 g / cm³ 3 Above, or 0.943 g / cm³ 3 Above, or 0.944 g / cm³ 3 Above, or 0.945 g / cm³ 3 That is all, 0.965 g / cm³ 3 Less than or equal to 0.964 g / cm³ 3 Less than or equal to 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 Less than or equal to 0.959 g / cm³ 3 Less than or equal to 0.958 g / cm³ 3 Less than or equal to 0.957 g / cm³ 3 Less than or equal to 0.956 g / cm³ 3 Less than or equal to 0.955 g / cm³ 3 It is as follows.

[0056] In the present invention, density can be measured according to ASTM D 1505 standards, for example, and may be a value measured at 23°C. As an example, the method for measuring such density is as described in the experimental examples described below.

[0057] When the density of the polyethylene satisfies the aforementioned range, the degradation of mechanical properties can be minimized while improving processability and environmental stress cracking resistance (ESCR) when mixed with recycled polyethylene. In other words, since mechanical properties deteriorate if the density is too low and environmental stress cracking resistance decreases if the density is too high, an optimized density range is required.

[0058]

[0059] In addition, polyethylene according to one embodiment of the present invention satisfies a Stress Crack Index (SCI) represented by Formula 1 of 300 or more:

[0060] [Equation 1]

[0061] SCI = 1,000 * ESCR / Mw

[0062] In Equation 1,

[0063] ESCR is environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) (unit: hours),

[0064] Mw is the weight-average molecular weight measured by GPC (unit: g / mol).

[0065]

[0066] In the present invention, the Stress Crack Index (SCI) of the polyethylene is a factor capable of evaluating mechanical properties. It can be calculated according to the formula of Equation 1 by measuring the environmental stress crack resistance (ESCR) of the polyethylene resin according to ASTM D 1693 (Condition B, F50, Igepal 10%) and measuring the weight-average molecular weight measured by GPC. Specific measurement methods and conditions are as described in the experimental examples below.

[0067] More specifically, the Stress Crack Index (SCI) represented by the above formula 1 may be 300 or more, or 305 or more, or 310 or more, or 320 or more, or 330 or more, or 340 or more, or 350 or more, or 360 or more, and 500 or less, or 490 or less, or 480 or less, or 470 or less, or 460 or less, or 450 or less, or 440 or less, or 430 or less, or 420 or less, or 410 or less, or 400 or less.

[0068] By having the SCI value as described above, when blended with recycled polyethylene, it is possible to improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties and processability, such as drop impact resistance.

[0069]

[0070] In addition, polyethylene according to one embodiment of the present invention may satisfy a Blow Processability Index (BPI) of 2.0 or higher as indicated by Formula 2:

[0071] [Equation 2]

[0072] BPI = Sagging time * Die swell ratio / Melt strength

[0073] In Equation 2,

[0074] Sagging time is the time (in seconds) taken for molten polyethylene to descend from 40 mm below the bottom of the orifice to 400 mm when extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 30 / s.

[0075] The die swell ratio is a value calculated as the ratio of (measured polyethylene diameter - orifice diameter) to the orifice diameter when molten polyethylene is extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 50 / s, and the diameter of the molten polyethylene is measured using a laser detector when the molten polyethylene reaches 240 mm below the orifice.

[0076] Melt strength was measured using a Rheotens 71.97 instrument when molten polyethylene reached 100 mm below the orifice using a capillary rheometer at a temperature of 210°C with an L / D=10 / 2 orifice and a shear rate of 72 mm / s (Rheotens Acceleration: 6 mm / s 2 ) is the measured value (unit: mN).

[0077] In the present invention, the Blow Processability Index (BPI) of the polyethylene is a factor capable of evaluating processability, and can be calculated according to the formula of Equation 2 by measuring the sagging time, die swell ratio, and melt strength using a capillary rheometer on the polyethylene resin. Specific measurement methods and conditions are as described in the experimental examples below.

[0078]

[0079] For reference, in the present invention, the capillary rheometer used to measure sagging time, die swell ratio, and melt strength is the Rheo-Tester 2000 model from GΦTTFERT, and the orifice used is of the standard with an L / D (length / diameter) of 10 / 2 and a diameter of 12 mm.

[0080]

[0081] More specifically, the Blow Processability Index (BPI) represented by the above Equation 2 may be 2.0 or higher, or 2.1 or higher, or 2.2 or higher, or 2.3 or higher, or 2.4 or higher, or 2.5 or higher, or 2.6 or higher, and 3.5 or lower, or 3.4 or lower, or 3.3 or lower, or 3.2 or lower, or 3.1 or lower, or 3.0 or lower.

[0082] By having the BPI value as described above, when blended with recycled polyethylene, it is possible to improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties and processability, such as drop impact resistance.

[0083]

[0084] In the above Equation 2, sagging time is a measurement of the phenomenon where molten resin sags downward due to gravity. It can be measured as the time (unit: seconds) it takes for molten polyethylene to descend from 40 mm below the bottom of the orifice to 400 mm when extruded at a temperature of 210°C with an orifice of L / D=10 / 2 and a diameter=12 mm using a capillary rheometer of the GΦTTFERT Rheo-Tester 2000 model at a shear rate of 30 / s.

[0085] The above-described polyethylene has a sagging time measured as described above that is 60 seconds or more, or 61 seconds or more, or 62 seconds or more, or 63 seconds or more, or 64 seconds or more, or 65 seconds or more, or 66 seconds or more, or 67 seconds or more, or 68 seconds or more, or 69 seconds or more, or 70 seconds or more, or 71 seconds or more, or 72 seconds or more, or 73 seconds or more, or 74 seconds or more, or 75 seconds or more, and is 100 seconds or less, or 99 seconds or less, or 98 seconds or less, or 97 seconds or less, or 96 seconds or less, or 95 seconds or less, or 94 seconds or less, or 93 seconds or less, or 92 seconds or less, or 91 seconds or less, or 90 seconds or less, or 89 seconds or less, or 88 seconds or less, or 87 seconds or less, or 86 seconds or less, or 85 seconds or less, or 89 seconds It may be less than or equal to 83 seconds.

[0086]

[0087] In the above Equation 2, the Die swell ratio is a value calculated as the ratio of (measured polyethylene diameter - orifice diameter) to the orifice diameter, after measuring the diameter of the molten polyethylene using a laser detector when the molten polyethylene is extruded at a temperature of 210°C with an orifice of L / D=10 / 2 and diameter=12 mm and a shear rate of 50 / s using a Capillary rheometer of the GΦTTFERT Rheo-Tester 2000 model and the molten polyethylene reaches 240 mm below the orifice.

[0088] The above polyethylene may have a die swell ratio measured as described above that is 1.3 or higher, or 1.32 or higher, or 1.35 or higher, and 1.6 or lower, or 1.55 or lower, or 1.5 or lower, or 1.45 or lower, or 1.4 or lower.

[0089]

[0090] In Equation 2 above, melt strength is used to measure the toughness of the molten resin; it is measured using a Rheotens 71.97 instrument when molten polyethylene is extruded using a GΦTTFERT Rheo-Tester 2000 model Capillary rheometer at a temperature of 210°C with an orifice of L / D=10 / 2 and diameter=12 mm at a shear rate of 72 mm / s, and the molten polyethylene reaches 100 mm from the bottom of the orifice (Rheotens Acceleration: 6 mm / s 2 ) is the measured value (unit: mN).

[0091] The above polyethylene may have a melt strength measured as described above of 30 mN or more, or 31 mN or more, or 32 mN or more, or 33 mN or more, or 34 mN or more, or 35 mN or more, and 40 mN or less, or 39 mN or less, or 38 mN or less.

[0092]

[0093] Meanwhile, the polyethylene according to the present invention may have a strain hardening modulus, molecular weight distribution, weight average molecular weight, and melt index optimized while optimizing the molecular structure along with the density as described above.

[0094]

[0095] Specifically, the polyethylene may have a Strain Hardening Modulus of 30 MPa or more as measured according to ISO 18488 standards. Preferably, the strain hardening modulus of the polyethylene may be 30 MPa or more, or 31 MPa or more, or 32 MPa or more, or 33 MPa or more, or 34 MPa or more, or 35 MPa or more, and 60 MPa or less, or 59 MPa or less, or 58 MPa or less, or 57 MPa or less, or 56 MPa or less, or 55 MPa or less, or 54 MPa or less, or 53 MPa or less, or 52 MPa or less, or 51 MPa or less, or 50 MPa or less, or 49 MPa or less, or 48 MPa or less, or 47 MPa or less, or 46 MPa or less, or 45 MPa or less, or 44 MPa or less, or 43 MPa or less, or 42 MPa or less, or 41 MPa or less, or 40 MPa or less.

[0096] By having a strain hardening modulus as described above, excellent mechanical properties can be maintained when compounded with recycled polyethylene, and processability and environmental stress crack resistance (ESCR) can be improved.

[0097]

[0098] In addition, the above polyethylene may have a molecular weight distribution (PDI, Mw / Mn) of 20 to 50. Preferably, the molecular weight distribution (Mw / Mn) of the above polyethylene may be 20 or more, or 21 or more, or 22 or more, and may be 50 or less, or 49 or less, or 48 or less, or 47 or less, or 46 or less, or 45 or less, or 44 or less, or 43 or less, or 42 or less, or 41 or less, or 40 or less, or 39 or less, or 38 or less, or 37 or less, or 36 or less, or 35 or less, or 34 or less, or 33 or less, or 32 or less, or 31 or less, or 30 or less.

[0099] By having the above molecular weight distribution, 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 processability and environmental stress crack resistance (ESCR) can be improved.

[0100] The above molecular weight distribution is measured using gel permeation chromatography (GPC). Specifically, it can be measured using the polystyrene conversion assay method with gel permeation chromatography (GPC, manufactured by Water).

[0101] Here, the molecular weight distribution 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.

[0102] Specifically, the Polymer Char GPC-IR instrument can be used as the gel permeation chromatography (GPC) device, and a Polymer Laboratories PLgel MIX-B 300 mm long column can be used. At this time, the measurement temperature is 160 ℃, 1,2,4-trichlorobenzene can be used as the solvent, and the flow rate can be applied at 1 mL / min. The polyethylene sample can be pretreated by dissolving it in trichlorobenzene containing 0.0125% butylated hydroxytoluene (BHT) at 160 ℃ for 10 hours using a GPC analyzer (PL-GP220), prepared to a concentration of 10 mg / 10 mL, and then supplied in an amount of 200 microliters (μL). The 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.

[0103]

[0104] In addition, the polyethylene may have a weight-average molecular weight of 100,000 g / mol to 500,000 g / mol. Preferably, the weight-average molecular weight of the polyethylene may be 100,000 g / mol or more, or 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 121,000 g / mol or more, or 122,000 g / mol or more, or 123,000 g / mol or more, or 124,000 g / mol or more, or 125,000 g / mol or more.However, considering compatibility with recycled polyethylene, the weight average molecular weight is 500,000 g / mol or less, or 490,000 g / mol or less, or 480,000 g / mol or less, or 470,000 g / mol or less, or 460,000 g / mol or less, or 450,000 g / mol or less, or 440,000 g / mol or less, or 430,000 g / mol or less, or 420,000 g / mol or less, or 410,000 g / mol or less, or 400,000 g / mol or less, or 390,000 g / mol or less, or 380,000 g / mol or less, or 370,000 g / mol or less, or 360,000 g / mol or less, or 350,000 g / mol or less. 340,000 g / mol or less, or 330,000 g / mol or less, or 320,000 g / mol or less, or 310,000 g / mol or less, or 300,000 g / mol or less, or 290,000 g / mol or less, or 280,000 g / mol or less, or 270,000 g / mol or less, or 260,000 g / mol or less, or 250,000 g / mol or less, or 240,000 g / mol or less, or 230,000 g / mol or less, or 220,000 g / mol or less, or 210,000 g / mol or less, or 200,000 g / mol or less, or 190,000 g / mol or less, or 180,000 g / mol or less, or 170,000 It may be g / mol or less, or 160,000 g / mol or less, or 150,000 g / mol or less, or 140,000 g / mol or less.

[0105]

[0106] By having the weight average molecular weight as described above, the molecular weight distribution of the polyethylene is optimized, and when combined with recycled polyethylene, processability and environmental stress crack resistance (ESCR) can be improved along with excellent mechanical properties.

[0107]

[0108] In addition, the above polyethylene has a melt index (MI). 2.16 (ASTM D 1238, 190 ℃, 2.16 kg) may be 0.1 g / 10 min to 1.5 g / 10 min. Preferably, the melt index (MI) of the polyethylene 2.16 ) may be 0.1 g / 10min or more, or 0.2 g / 10min or more, or 0.3 g / 10min or more, or 0.4 g / 10min or more, or 0.5 g / 10min or more, and 1.5 g / 10min or less, or 1.4 g / 10min or less, or 1.3 g / 10min or less, or 1.2 g / 10min or less, or 1.1 g / 10min or less, or 1.0 g / 10min or less. As described above, the melt index (MI) of polyethylene 2.16 By having ), it has excellent compatibility with recycled polyethylene, optimizes the molecular weight distribution of polyethylene, and can improve environmental stress crack resistance (ESCR) along with excellent mechanical properties when combined with recycled polyethylene.

[0109]

[0110] 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.

[0111]

[0112] For example, the 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.

[0113] [Chemical Formula 1]

[0114] (Cp 1 R a )n (Cp 2 R b )M 1 Z 1 3-n

[0115] In the above chemical formula 1,

[0116] M 1 It is a Group 4 transition metal;

[0117] Cp 1 and Cp 2 are each cyclopentadiennyl, and these are C 1-20 Substituted with or unsubstituted with hydrocarbons;

[0118] R a and R b are identical or different from each other, and independently hydrogen, C 1-20 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 of, C 7-40 arylalkyl of, C 8-40 of Arylalkenil, 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 is an arylalkyl, and the other one is C 2-20 It is an alkoxyalkyl;

[0119] 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 7-40It is an aryl alkoxy;

[0120] n is 1 or 0 and;

[0121] [Chemical Formula 2]

[0122]

[0123] In the above chemical formula 2,

[0124] C1 is any one of the ligands represented by the following chemical formulas 3 to 6, and

[0125] [Chemical Formula 3]

[0126]

[0127] [Chemical Formula 4]

[0128]

[0129] [Chemical Formula 5]

[0130]

[0131] [Chemical Formula 6]

[0132]

[0133] In the above chemical formulas 3 to 6,

[0134] 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 of, C 8-40 alkenylaryl of, C 8-40 alkynylaryl of, C 7-40 arylalkyl of, C 8-40 aryl alkenyl of, or C 8-40 It is an aryl alkinil of, and

[0135] M is Ti, Zr, or Hf, and

[0136] Z is -O-, -S-, -NR7- or -PR7-, and

[0137] 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 of, C 8-40 alkenylaryl of, C 8-40 alkynylaryl of, C 7-40 arylalkyl of, C 8-40 of Arylalkenil, C 8-40 arylalkinyl of, C 1-30 Alkoxysilyl group, C 6-30 Aryloxysilyl, C 1-30 Alkylsilyl group, or C 1-30 It is a silylalkyl group, and

[0138] X1 and X2 are 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

[0139] T is or And,

[0140] T1 is C, Si, Ge, Sn, or Pb, and

[0141] 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 of, C 8-40 alkenylaryl of, C8-40 alkynylaryl of, C 7-40 arylalkyl of, C 8-40 aryl alkenyl of, 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,

[0142] Y2 is C 2-30 Alkoxyalkyl, or C 7-40 It is an aryloxyalkyl, and

[0143] R9 and R 10 Each independently 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 of, C 8-40 alkenylaryl of, C 8-40 alkynylaryl of, C 7-40 arylalkyl of, C 8-40 aryl alkenyl of, or C 8-40 It is an arylalkynyl, or connected to form an aliphatic or aromatic ring.

[0144]

[0145] Meanwhile, unless otherwise specifically limited in this specification, the following terms may be defined as follows.

[0146]

[0147] Halogens can be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

[0148]

[0149] 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 1-10Straight-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 cyclic alkyl group. More specifically, the C1-20 alkyl group may be a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a neo-pentyl group, or a cyclohexyl group, etc.

[0150]

[0151] 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, C 2-5 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.

[0152]

[0153] 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.

[0154]

[0155] 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 7-40The alkylaryl may be methylphenyl, ethylphenyl, n-propylphenyl, iso-propylphenyl, n-butylphenyl, iso-butylphenyl, tert-butylphenyl, or cyclohexylphenyl, etc.

[0156]

[0157] 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.

[0158]

[0159] 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.

[0160]

[0161] The above C 2-20 The 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.

[0162]

[0163] The above C 1-20 alkylsilyl group or C 1-20The 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.

[0164]

[0165] 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.

[0166]

[0167] 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.

[0168]

[0169] The above heteroaryl comprises one or more of N, O, and S as heteroelements, C 2-20As 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.

[0170]

[0171] 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.

[0172]

[0173] 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 10 Examples of these interconnected groups forming an aliphatic ring include piperidinyl groups, and -NR9R 10 R9 and R 10Examples of groups connected to form an aromatic ring include pyrrolyl groups.

[0174]

[0175] In addition, group 4 transition metals include titanium (Ti), zirconium (Zr), hafnium (Hf), etc., but are not limited to these.

[0176]

[0177] 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 It can be substituted with 1 or more alkyl groups or 1 to 3.

[0178]

[0179] 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 7-40 C 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 7-20C 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 is an arylalkyl, and the rest R a and R b At least one of them is C 2-20 It is an alkoxyalkyl.

[0180]

[0181] 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.

[0182]

[0183] 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 arylalkyl, but R a and R b At least one of them is an alkyl such as methyl or butyl, or an aryl alkyl such as phenylpropyl, and the remainder Ra and R b At least one of them may be a compound having an alkoxyalkyl group such as a t-butoxyhexyl group, more specifically -(CH2)n-OR (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).

[0184]

[0185] 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.

[0186]

[0187]

[0188] In addition, 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.

[0189]

[0190] More specifically, in the above chemical formula 2, M is Ti, Zr, or Hf, and more specifically, may be Ti.

[0191]

[0192] 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.

[0193]

[0194] Also, R5 and R6 each independently C 1-10 It is alkyl, and more specifically, both R5 and R6 can be methyl.

[0195]

[0196] Also, Z is -NR7-, and the above R7 is C 1-10Alkyl, more specifically C such as t-butyl 3-10 It can be a branched alkyl.

[0197]

[0198] 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.

[0199]

[0200] Also, X1 and X2 are each independently halogen or C 1-20 It is an alkyl, and more specifically, it can be chloro or methyl.

[0201]

[0202] 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.

[0203] 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.

[0204] In this way, by mixing and using 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, polyethylene with optimized molecular structure and density can be produced.

[0205] [Chemical Formula 2a]

[0206]

[0207] [Chemical Formula 2b]

[0208]

[0209] [Chemical Formula 2c]

[0210]

[0211] [Chemical Formula 2d]

[0212]

[0213] In the above chemical formulas 2a to 2d, R1 to R7, M, X1, X2, T1, Y1, and Y2 are as previously defined.

[0214]

[0215] 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 7-30 It 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.

[0216]

[0217] More specifically, specific examples of the second metallocene compound may include compounds having the following structures, but are not limited thereto:

[0218]

[0219] .

[0220]

[0221] In addition, 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.

[0222] In addition, the 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.

[0223]

[0224] 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.

[0225]

[0226] 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.

[0227]

[0228] 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.

[0229]

[0230] Meanwhile, in a polyethylene composition according to one embodiment of the present invention, the aforementioned novel polyethylene is prepared by polymerizing ethylene using the aforementioned catalyst composition, and the polymerization process can be carried out as a monomodal (or unimodal) polymerization process in which a polymerization reaction is performed 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 aforementioned hybrid supported catalyst.

[0231]

[0232] At this time, the polymerization temperature may be 25 ℃ to 500 ℃, preferably 25 ℃ to 200 ℃, and more preferably 50 ℃ to 150 ℃. In addition, the polymerization pressure may be 1 Kgf / ㎠ to 100 Kgf / ㎠, preferably 1 Kgf / ㎠ to 50 Kgf / ㎠, and more preferably 5 Kgf / ㎠ to 30 Kgf / ㎠.

[0233]

[0234] 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.

[0235]

[0236] 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.

[0237] In particular, the polyethylene composition according to the present invention uses polyethylene with a molecular structure optimized along with density as described above, thereby improving environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties when combined with recycled polyethylene, so that excellent mechanical properties, processability, and environmental stress cracking resistance close to those of virgin resin can be secured even when combined with recycled polyethylene.

[0238]

[0239] For example, in a polyethylene composition, the virgin polyethylene may be included in an amount of 5 to 20 parts by weight based on 100 parts by weight of the total composition, and the recycled polyethylene may be included in an amount of 15 to 50 parts by weight based on 100 parts by weight of the total composition.

[0240] More specifically, in terms of improving the ESCR of the polyethylene composition, enhancing the effect of suppressing carbon dioxide emissions, and achieving physical properties equivalent to those of virgin resin, the content of the virgin polyethylene may be 5 parts by weight or more, or 10 parts by weight or more, and 20 parts by weight or less, or 18 parts by weight or less, and the content of the recycled polyethylene resin (PCW PE) may be 15 parts by weight or more, or 20 parts by weight or more, or 25 parts by weight or more, and 50 parts by weight or less, or 45 parts by weight or less, or 30 parts by weight or less.

[0241]

[0242] Meanwhile, the above-mentioned recycled polyethylene (PCW PE) has a density of 0.940 to 0.960 g / cm³ as measured according to ASTM D 1505, 23 ℃. 3 It may be. More specifically, the density of the recycled polyethylene (PCW PE) is 0.940 g / cm³. 3 Above, or 0.943 g / cm³ 3 Above, or 0.945 g / cm³3 Above, or 0.948 g / cm³ 3 Above, 0.950 g / cm³ 3 It may be greater than 0.960 g / cm³ 3 Less than or equal to 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.

[0243] In addition, the above recycled polyethylene (PCW PE) has a melt index (MI 2.16 , measured at 190 ℃, under a 2.16 kg load) may be 0.4 g / 10 min to 0.7 g / 10 min.

[0244] In addition, the above recycled polyethylene (PCW PE) may have an environmental stress crack resistance (ESCR) of 40 to 60 hours as measured according to ASTM D 1693 (Condition B, F50, Igepal 10%).

[0245]

[0246] According to one embodiment of the present invention, the polyethylene composition may additionally include polyethylene with different physical properties in addition to the novel polyethylene and recycled polyethylene of the present invention described above. The polyethylene that can be added is not particularly limited as long as it is high-density polyethylene (HDPE) compatible with the novel polyethylene and recycled polyethylene of the present invention, and general-purpose high-density polyethylene and commercially available products may be used. In addition, the content is not particularly limited, but may be used in an amount of 30 to 80 parts by weight based on 100 parts by weight of the total composition.

[0247]

[0248] Meanwhile, the polyethylene composition according to the present invention can secure excellent ESCR close to that of virgin resin while increasing the recycled polyethylene content.

[0249] For example, the above polyethylene composition may have an environmental stress cracking resistance (ESCR) of 200 hours or more as measured according to ASTM D 1693 (Condition B, F50, Igepal 10%).

[0250] More specifically, the polyethylene composition may have an environmental stress crack resistance (ESCR) of 200 hours or more, or 210 hours or more, or 220 hours or more, or 230 hours or more, or 240 hours, and 500 hours or less, or 400 hours or less, or 350 hours or less, or 300 hours or less.

[0251]

[0252] In addition, the above polyethylene composition can satisfy the following conditions (1) and (2).

[0253] (1) SCI (Stress Crack Index) represented by Equation 1 is 1.4 or higher;

[0254] [Equation 1]

[0255] SCI = 1,000 * ESCR / Mw

[0256] In Equation 1,

[0257] ESCR is environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) (unit: hours),

[0258] Mw is the weight-average molecular weight measured by GPC (unit: g / mol),

[0259] (2) The Blow Processability Index (BPI) represented by Equation 2 is 2.0 or higher;

[0260] [Equation 2]

[0261] BPI = Sagging time * Die swell ratio / Melt strength

[0262] In Equation 2,

[0263] Sagging time is the time (in seconds) taken for a molten polyethylene composition to descend from 40 mm below the bottom of the orifice to 400 mm when the molten polyethylene composition is extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 30 / s.

[0264] The die swell ratio is a value calculated as the ratio of (measured polyethylene diameter - orifice diameter) to the orifice diameter when the diameter of the molten polyethylene is measured using a laser detector when the molten polyethylene composition reaches 240 mm below the orifice, after the molten polyethylene composition is extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 50 / s.

[0265] Melt strength was measured using a Rheotens 71.97 instrument when the molten polyethylene composition reached 100 mm below the orifice using a capillary rheometer at a temperature of 210°C through an orifice with L / D = 10 / 2 and a shear rate of 72 mm / s (Rheotens Acceleration: 6 mm / s 2 ) is the measured value (unit: mN).

[0266] The description of the above formulas 1 and 2 is the same as that for polyethylene, except that the subject being measured is a polyethylene composition.

[0267]

[0268] More specifically, the polyethylene composition may have an SCI represented by Formula 1 of 1.4 or higher, or 1.41 or higher, or 1.42 or higher, and 3.0 or lower, or 2.5 or lower, or 2.0 or lower, or 1.8 or lower.

[0269] In addition, the polyethylene composition may have a Blow Processability Index (BPI) represented by Formula 2 that is 2.0 or higher, or 2.1 or higher, or 2.2 or higher, or 2.3 or higher, or 2.4 or higher, or 2.5 or higher, or 2.6 or higher, and 3.5 or lower, or 3.4 or lower, or 3.3 or lower, or 3.2 or lower, or 3.1 or lower, or 3.0 or lower.

[0270] In addition, the polyethylene composition may have a sagging time of 105 seconds or more, or 106 seconds or more, or 107 seconds or more, and 115 seconds or less, or 114 seconds or less, or 113 seconds or less, as measured as described above.

[0271] In addition, the above polyethylene composition may have a die swell ratio measured as described above that is 1.5 or higher, or 1.52 or higher, or 1.53 or higher, or 1.55 or higher, or 1.57 or higher, and 1.7 or lower, or 1.65 or lower, or 1.63 or lower, or 1.62 or lower.

[0272] In addition, the polyethylene composition may have a melt strength measured as described above of 60 mN or more, or 61 mN or more, or 62 mN or more, or 63 mN or more, or 64 mN or more, or 65 mN or more, or 66 mN or more, and 80 mN or less, or 79 mN or less, or 78 mN or less, or 77 mN or less, or 76 mN or less, or 75 mN or less, or 74 mN or less.

[0273]

[0274] In addition, the polyethylene composition has a density of 0.940 g / cm³ as measured according to ASTM D 1505, 23 ℃. 3 The above is true, and more specifically, 0.940 to 0.960 g / cm³ 3 It could be.

[0275] At this time, the method for measuring the physical properties of the polyethylene composition is as described above with respect to polyethylene, and the polyethylene composition can be measured instead of polyethylene using this method, and specific details are omitted.

[0276]

[0277] 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.

[0278]

[0279] <Example>

[0280] Manufacture of Polyethylene

[0281] Example 1-1

[0282] High-density new polyethylene was manufactured through a single slurry polymerization process as follows.

[0283] First, 15 kg / h of isobutane and 33 kg / h of ethylene were injected into a single slurry loop reactor, and hydrogen was injected at a flow rate of 150 ppm, respectively. Then, 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 0.02 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 temperature. Subsequently, high-density virgin polyethylene (HDPE, Virgin polyethylene), a high-density ethylene / 1-hexene copolymer in powder form, was produced by passing it through a solvent removal facility and a dryer.

[0284] (1) (2)

[0285] (3)

[0286]

[0287]

[0288] Examples 1-2

[0289] High-density new polyethylene was prepared in the same manner as in Example 1-1, except that the hydrogen flow rate was changed to 140 ppm and the amount of 1-hexene added was changed to 0.15 wt%.

[0290]

[0291] Examples 1-3

[0292] High-density new polyethylene was prepared in the same manner as in Example 1-1, except that the hydrogen flow rate was changed to 145 ppm and the amount of 1-hexene added was changed to 0.12 wt%.

[0293]

[0294] Comparative Example 1-1

[0295] A commercially available high-density polyethylene (HDPE) product manufactured using a metallocene catalyst (LG Chem product, product name SP4701) was prepared as Comparative Example 1-1.

[0296]

[0297] Comparative Example 1-2

[0298] 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 2.16 A high-density polyethylene product (LG Chem’s ME8000 product) with a density of 8 g / 10 min was dry-blended and prepared as Comparative Example 1-2.

[0299]

[0300] Comparative Examples 1-3

[0301] For a commercially available high-density polyethylene (HDPE) product (LG Chem product, product name SP4701) manufactured using a metallocene catalyst, a density of 0.956 g / cm³ 3 , Melt Index (MI 2.16 A high-density polyethylene product (LG Chem’s CE2080 product) with a density of 0.24 g / 10 min was dry-blended and prepared as Comparative Example 1-3.

[0302]

[0303] <Preparation of Polyethylene Composition>

[0304] Example 2-1

[0305] A polyethylene composition (PCR Compound) was prepared by dry blending 10 wt% of the polyethylene prepared in Example 1-1 using virgin polyethylene, 60 wt% of high-density polyethylene, and 30 wt% of recycled polyethylene (PCW PE, Post consumer waste polyethylene), and then extruding it through a twin screw extruder.

[0306] High-density polyethylene and recycled polyethylene are as follows:

[0307] High-density polyethylene: A commercially available Booster Grade High-density Polyethylene (HDPE) product for PCR manufactured using a Ziegler-Natta catalyst (Z / N catalyst), Lotte Chemical's product name 6200B.

[0308] Recycled Polyethylene: BSN Hakusan Natural Color product from Hakusan Plastics, Melt Index MI 2.16 (Measured under a 2.16 kg load at 190 ℃ according to ASTM D 1238 (Condition E)) 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 (time to F50 (50% destruction) measured under 50°C conditions using 10% Igepal CO-630 Solution according to ASTM D 1693) is 40~50 hours.

[0309]

[0310] Example 2-2

[0311] A polyethylene composition was prepared in the same manner as in Example 2-1, except that the polyethylene prepared in Example 1-2 was used instead of the polyethylene prepared in Example 1-1 using new polyethylene.

[0312]

[0313] Examples 2-3

[0314] A polyethylene composition was prepared in the same manner as in Example 2-1, except that the polyethylene prepared in Example 1-3 was used instead of the polyethylene prepared in Example 1-1 using new polyethylene.

[0315]

[0316] Comparative Example 2-1

[0317] A polyethylene composition was prepared in the same manner as in Example 2-1, except that the polyethylene prepared in Comparative Example 1-1 was used instead of the polyethylene prepared in Example 1-1 using new polyethylene.

[0318]

[0319] Comparative Example 2-2

[0320] A polyethylene composition was prepared in the same manner as in Example 2-1, except that polyethylene prepared in Comparative Example 1-2 was used instead of polyethylene prepared in Example 1-1 using new polyethylene.

[0321]

[0322] Comparative Example 2-3

[0323] A polyethylene composition was prepared in the same manner as in Example 2-1, except that polyethylene prepared in Comparative Example 1-3 was used instead of polyethylene prepared in Example 1-1 using new polyethylene.

[0324]

[0325] <Experimental Example: Evaluation of Physical Properties of Polyethylene>

[0326] The physical properties of the polyethylene or polyethylene composition of the examples and comparative examples were evaluated in the following manner, and the measurement results for polyethylene are shown in Table 1 below, and the measurement results for the polyethylene composition (PCR compound) are shown in Table 2 below.

[0327]

[0328] (1) Density (unit: g / cm³)

[0329] Density of polyethylene at 23°C according to ASTM D 1505 (g / cm³) 3 ) was measured.

[0330]

[0331] (2) Weight-average molecular weight (unit: g / mol) and molecular weight distribution

[0332] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polyethylene were measured using gel permeation chromatography (GPC, manufactured by Water), and the molecular weight distribution (PDI, Mw / Mn) was calculated by dividing the weight-average molecular weight by the number-average molecular weight.

[0333] Specifically, a Waters PL-GPC220 instrument was used for gel permeation chromatography (GPC), 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 the examples and comparative examples were each pretreated by dissolving them in trichlorobenzene (1,2,4-trichlorobenzene) containing 0.0125% butylated hydroxytoluene (BHT) at 160 ℃ for 10 hours using a GPC analyzer (PL-GP220), 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.

[0334]

[0335] (3) Environmental stress cracking resistance (ESCR, unit: hours)

[0336] According to the method of ASTM D 1693-07, the time to F50 (50% destruction) was measured for polyethylene and polyethylene composition (PCR Compound) using 10% Igepal CO-630 Solution at a temperature of 50 ℃ under Condition B.

[0337]

[0338] (4) Sagging time (unit: seconds)

[0339] The time taken for molten polyethylene or a polyethylene composition to descend from 40 mm below the bottom of the orifice to 400 mm using a capillary rheometer (Rheo-Tester 2000 of GΦTTFERT) at a temperature of 210℃ with an orifice of L / D=10 / 2 and a diameter=12 mm and a shear rate of 30 / s was measured (unit: seconds).

[0340]

[0341] (5) Die swell ratio

[0342] When extruding at a temperature of 210°C with a capillary rheometer (Rheo-Tester 2000 of GΦTTFERT) at an orifice with L / D=10 / 2 and a diameter=12 mm and a shear rate of 50 / s, the diameter of the molten polyethylene or polyethylene composition was measured using a laser detector when it reached 240 mm below the orifice, and the value calculated as the ratio of (measured polyethylene diameter - orifice diameter) to the orifice diameter was defined as the Die swell ratio.

[0343]

[0344] (6) Melt strength (unit: mN)

[0345] When extruded at a temperature of 210°C at a shear rate of 72 mm / s using a capillary rheometer (GΦTTFERT’s Rheo-Tester 2000) through an orifice with L / D=10 / 2 and a diameter of 12 mm, measurement was taken with a Rheotens 71.97 instrument when the molten polyethylene reached 100 mm from the bottom of the orifice (Rheotens Acceleration: 6 mm / s 2 ) did.

[0346]

[0347] (7) Strain Hardening Modulus (SH Modulus, unit: MPa)

[0348] SH Modulus was measured in an 80°C oven using a Zwick UTM according to ISO 18488 standards.

[0349] Specifically, a strain / stress curve was measured according to ISO 18488 under conditions of 80 ℃ and 5 mm / min, and a Neo-Hookean constitutive model curve was obtained from it. Then, the slope of the linear fitting value between true strain 8 and 12 was calculated from the Neo-Hookean constitutive model curve to obtain the strain hardening modulus.

[0350]

[0351] (8) Relaxation time (unit: seconds)

[0352] The relaxation time (seconds) was measured using the ARES-G2, a rotary rheometer from TA Instruments.

[0353] More specifically, using ARES-G2, viscosity was measured at 150 ℃, 170 ℃, 190 ℃, 210 ℃, and 230 ℃ at each temperature under conditions of Strain 0.5% and Frequency 0.1 to 500 rad / s, at each frequency (Angular Frequency) 0.05 rad / s to 500 rad / s. From the viscosity values ​​measured at each temperature, the relaxation time (seconds) at each temperature was calculated using the cross model of Equation 3 below.

[0354] [Equation 3]

[0355] η = η ∞ + (η0 - η ∞ ) / (1 + λ × (Shear rate) m )

[0356] In the above Equation 3,

[0357] The above η is the viscosity of polyethylene measured using a rotational rheometer under conditions of each measurement temperature among 150 ℃, 170 ℃, 190 ℃, 210 ℃, and 230 ℃ and each frequency (Angular Frequency) of 0.05 rad / s to 500 rad / s, and

[0358] The above η ∞ is an infinite shear viscosity, and

[0359] The above η0 is the zero-point shear viscosity, and

[0360] The above shear rate is the shear rate applied to polyethylene and is equal to the angular frequency, and

[0361] The above λ and m are parameters obtained by fitting a log-log graph with angular frequency on the x-axis and viscosity measurement η on the y-axis using the cross model of Equation 2,

[0362] The above λ is the relaxation time (seconds) of the polyethylene composition, which is the reciprocal of the angular frequency at which viscosity η begins to decrease, and

[0363] The above m is the slope of viscosity η in the region where viscosity η decreases.

[0364]

[0365] Unit Example 1-1 Example 1-2 Example 1-3 Comparative Example 1-1 Comparative Example 1-2 Comparative Example 1-3 Density g / cm³ 3 0.9453 0.9456 0.9462 0.9458 0.9509 0.9495 Weight-average molecular weight g / mol 148,100 150,800 145,600 156,100 116,800 147,100 ESCR time 55,157 46,145 55,157 26,074 18,250 37,252 SCI 37 2.4 330 637 8.8 316 7.03 156.25 253.24 Sagging time 738 276 78 6081 Die swell ratio 1.38 1.38 1.35 1.4 11.25 1.4 Melt strengthN384037453243BPI2.652.832.772.442.342.64SCI x BPI987.33865.681050.47408.23366.21667.85MI 2.16 g / 10min0.550.470.530.521.080.46PDI22.3924.826.820.123.5125.22SH ModulusMPa37.637.137.635.534.536.5Relaxation time seconds0.80.70.61.40.40.9

[0366] Unit Example 2-1 Example 2-2 Example 2-3 Comparative Example 2-1 Comparative Example 2-2 Comparative Example 2-3 Density g / cm³ 30.95130.95260.95290.95240.95390.9537 Weight-average molecular weight 167200163600162400161300159400161500 ESCR time 300240230155145170 SCI 1.791.471.420.960.911.05 Sagging time sec 11311010710399105 Die swell ratio 1.611.581.581.571.51.57 Melt strength 706867635865 BPI 2.62.562.522.572.562.54 SCI x BPI4.663.753.572.472.332.67MI 2.16 g / 10min 0.25 0.26 0.26 0.28 0.29 0.27PDI 2119.4 20.7 19.7 19.1 8.3Relaxation time sec 10.8 10.4 10.3 7.7 7.1 7.9

[0367] Referring to Tables 1 and 2 above, it can be seen that when using the polyethylene of Examples 1-1 to 1-3, which has a molecular structure optimized along with density according to the present invention, excellent processability is maintained when combined with recycled polyethylene (PCW PE), and at the same time, environmental stress cracking resistance (ESCR) can be significantly improved to over 200 hours.

Claims

1. Polyethylene satisfying the following conditions (1) to (2): (1) Density of 0.940 g / cm³ measured according to ASTM D 1505, 23 ℃ 3 more; (2) SCI (Stress Crack Index) represented by Equation 1 is 300 or higher; [Equation 1] SCI = 1,000 * ESCR / Mw In Equation 1, ESCR is environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) (unit: hours), Mw is the weight-average molecular weight (unit: g / mol) measured by GPC.

2. In Paragraph 1, Polyethylene that further satisfies a Blow Processability Index (BPI) of 2.0 or higher, as indicated by Equation 2: [Equation 2] BPI = Sagging time * Die swell ratio / Melt strength In Equation 2, Sagging time is the time (in seconds) taken for molten polyethylene to descend from 40 mm below the bottom of the orifice to 400 mm when extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 30 / s. The die swell ratio is a value calculated as the ratio of (measured polyethylene diameter - orifice diameter) to the orifice diameter when molten polyethylene is extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 50 / s, and the diameter of the molten polyethylene is measured using a laser detector when the molten polyethylene reaches 240 mm below the orifice. Melt strength was measured using a Rheotens 71.97 instrument when molten polyethylene reached 100 mm below the orifice using a capillary rheometer at a temperature of 210°C with an L / D=10 / 2 orifice and a shear rate of 72 mm / s (Rheotens Acceleration: 6 mm / s 2 ) is the measured value (unit: mN).

3. In Paragraph 1, Sagging time of 60 to 100 seconds, Polyethylene.

4. In Paragraph 1, A die swell ratio of 1.3 to 1.6, Polyethylene.

5. In Paragraph 1, Having a melt strength of 30 to 40 mN, Polyethylene.

6. In Paragraph 1, A strain hardening modulus (condition: 50℃, 5 mm / min; strain: measured under 700 ~ 1,100%) of 30 to 60 MPa, Polyethylene.

7. In Paragraph 1, Density of 0.940 to 0.965 g / cm³ measured according to ASTM D 1505, 23 ℃ 3 person, Polyethylene.

8. In Paragraph 1, molecular weight distribution (PDI, Mw / Mn) of 20 to 50, Polyethylene.

9. In Paragraph 1, Melt Index (MI) measured at 190°C and a 2.16 kg load according to ASTM D 1238 2.16 ) having 0.1 to 1.5 g / 10 min, Polyethylene.

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

11. 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 10, Polyethylene composition.

12. In Paragraph 11, The above-mentioned novel polyethylene is included in an amount of 5 to 20 parts by weight based on 100 parts by weight of the total composition, and The above recycled polyethylene is included in an amount of 15 to 50 parts by weight based on 100 parts by weight of the total composition, Polyethylene composition.

13. In claim 11, the polyethylene composition satisfies the following conditions (1) and (2). (1) SCI (Stress Crack Index) represented by Equation 1 is 1.4 or higher; [Equation 1] SCI = 1,000 * ESCR / Mw In Equation 1, ESCR is environmental stress crack resistance (ESCR) measured according to ASTM D 1693 (Condition B, F50, Igepal 10%) (unit: hours), Mw is the weight-average molecular weight measured by GPC (unit: g / mol), (2) The Blow Processability Index (BPI) represented by Equation 2 is 2.0 or higher; [Equation 2] BPI = Sagging time * Die swell ratio / Melt strength In Equation 2, Sagging time is the time (in seconds) taken for a molten polyethylene composition to descend from 40 mm below the bottom of the orifice to 400 mm when the molten polyethylene composition is extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 30 / s. The die swell ratio is a value calculated as the ratio of (measured polyethylene diameter - orifice diameter) to the orifice diameter when the diameter of the molten polyethylene is measured using a laser detector when the molten polyethylene composition reaches 240 mm below the orifice, after the molten polyethylene composition is extruded using a capillary rheometer at a temperature of 210°C with an orifice of L / D = 10 / 2 and a shear rate of 50 / s. Melt strength was measured using a Rheotens 71.97 instrument when the molten polyethylene composition reached 100 mm below the orifice using a capillary rheometer at a temperature of 210°C through an orifice with L / D = 10 / 2 and a shear rate of 72 mm / s (Rheotens Acceleration: 6 mm / s 2 ) is the measured value (unit: mN).

14. In Paragraph 11, The above polyethylene composition has a sagging time of 105 to 115 seconds, Polyethylene composition.

15. In Paragraph 11, The above polyethylene composition has a die swell ratio of 1.5 to 1.7, Polyethylene composition.

16. In Paragraph 11, The above polyethylene composition has a melt strength of 60 to 80 mN, Polyethylene composition.

17. In Paragraph 11, 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, Polyethylene composition.

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