Polyethylene and composition comprising same

Abstract

The present invention provides polyethylene having improved 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. 10-2024-0133312 filed September 30, 2024 and Korean Patent Application No. 10-2025-0141599 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 resistance to environmental stress cracking 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 resistance to environmental stress cracking while maintaining excellent mechanical properties, such as drop impact strength, when combined with recycled polyethylene, and a polyethylene composition containing the same.

[0012]

[0013] According to one embodiment of the invention, polyethylene is provided that satisfies (1) to (4) below.

[0014] (1) Density of 0.944 g / cm³ measured according to ASTM D 1505, 23 ℃ 3 more;

[0015] (2) 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 greater is 15% or less of the total integral value;

[0016] (3) When analyzed by cross-fractionation chromatography (CFC), the content ratio of the low-crystallinity fraction eluted at a temperature of 60 to 90 ℃ is 60% or more of the total weight of the eluted fraction;

[0017] (4) When analyzed by cross-fractionation chromatography (CFC), the content ratio of the soluble fraction eluted at a temperature of 20 to 30 ℃ is 2.0% or more of the total weight of the eluted fraction.

[0018]

[0019] 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.

[0020]

[0021] According to the present invention, by optimizing the molecular structure along with density to optimize the ratio of the polymer region, the content of low-crystallinity components, and the soluble fraction, it is possible to provide polyethylene that improves resistance to environmental stress cracking while maintaining mechanical properties such as excellent drop impact strength when blended with recycled polyethylene.

[0022] Accordingly, when the above polyethylene is combined with a recycled resin, a recycled polyethylene composition with excellent mechanical properties and improved resistance to environmental stress cracking can be provided.

[0023]

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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%.

[0029] 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.

[0030]

[0031] The present invention will be described in more detail below.

[0032]

[0033] 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 polymer region, the content of the low-crystallinity component, and the content of the soluble fraction, so as to improve environmental stress cracking resistance (ESCR) while maintaining excellent mechanical properties even when combined with recycled polyethylene.

[0034]

[0035] Specifically, the polyethylene of the present invention has a density of 0.944 g / cm³ as measured according to ASTM D 1505, 23 ℃. 3In the above, 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 5.5 or higher is 15% or less of the total integral value, the content ratio of the low-crystallinity fraction eluted at a temperature of 60 to 90 ℃ during cross-fractionation chromatography (CFC) analysis is 60% or more of the total weight of the eluted fraction, and the content ratio of the soluble fraction eluted at a temperature of 20 to 30 ℃ during cross-fractionation chromatography (CFC) analysis is 2.0% or more of the total weight of the eluted fraction.

[0036]

[0037] The polyethylene of the present invention will be described in more detail below.

[0038]

[0039] Specifically, the polyethylene according to one embodiment of the present invention may be an ethylene homopolymer or an ethylene / alpha-olefin copolymer.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044]

[0045] Polyethylene according to one embodiment of the present invention has a density of 0.944 g / cm³ as measured according to ASTM D 1505, 23 ℃. 3 Satisfies the ideal.

[0046] More specifically, the density of the polyethylene is 0.944 g / cm³3 Above, or 0.945 g / cm³ 3 Above, or 0.946 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.

[0047] 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.

[0048] When the density of the above-mentioned polyethylene satisfies the aforementioned range, when mixed with recycled polyethylene, it is possible to improve environmental stress cracking resistance (ESCR) while minimizing the degradation of mechanical properties such as drop impact.

[0049]

[0050] In addition, for 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 in the region where the log Mw value is 5.5 or higher is 15% or less of the total integral value.

[0051] More specifically, the integral value of the region where the log Mw value is 5.5 or higher may be 15% or less, or 14.9% or less, or 14.8% or less, or 14.7% or less, or 14.6% or less, and 10% or more, or 11% or more, or 12% or more, or 13% or more.

[0052] By having an integral value ratio in the region where the log Mw value is 5.5 or higher as described above, when combined with recycled polyethylene, it is possible to improve environmental stress crack resistance (ESCR) while maintaining excellent mechanical properties and processability, such as drop impact.

[0053] The proportion of the region where the above Log Mw value is 5.5 or higher is measured using gel permeation chromatography (GPC). Specifically, it can be measured using the polystyrene conversion test method with gel permeation chromatography (GPC, manufactured by Water), and a more specific measurement method is as described in the experimental examples below.

[0054]

[0055] In addition, the polyethylene has a content ratio of low-crystallinity fraction eluted at a temperature of 60 to 90°C during cross-fractionation chromatography (CFC) analysis of 60% or more of the total weight of the eluted fraction.

[0056] More specifically, the content ratio of the low-crystallinity fraction eluted at a temperature of 60 to 90 ℃ during the cross-fraction chromatography analysis may be 60% or more, or 61% or more, or 62% or more, or 63% or more, or 64% or more, and 80% or less, or 79% or less, or 78% or less, or 77% or less, or 76% or less, or 75% or less, or 74% or less, or 73% or less, or 72% or less, or 71% or less, or 70% or less, or 69% or less, or 68% or less.

[0057] By having the content ratio of the low-crystallinity fraction 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.

[0058]

[0059] In addition, the above polyethylene has a content ratio of the soluble fraction eluted at a temperature of 20 to 30°C during cross-fractionation chromatography (CFC) analysis of 2.0% or more of the total weight of the eluted fraction.

[0060] More specifically, the content ratio of the soluble fraction eluted at a temperature of 20 to 30°C in the cross-fraction chromatography may be 2% or more, or 2.1% or more, or 2.2% or more, or 2.3% or more, and 3.0% or less, or 2.9% or less, or 2.8% or less, or 2.7% or less, or 2.6% or less, or 2.5% or less.

[0061] By having the above-mentioned content ratio of the soluble fraction, 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.

[0062]

[0063] In the present invention, the content of the low-crystallinity fraction or the content or ratio of the soluble fraction is calculated as a percentage (wt%) of the fraction eluted within the corresponding elution temperature range, based on the total weight of the total eluted fraction obtained through cross-fraction chromatography (CFC) analysis. Specific measurement methods and conditions are as described in the experimental examples below.

[0064]

[0065] Meanwhile, the polyethylene according to the present invention may have a molecular weight distribution, weight average molecular weight, and melt index optimized by optimizing the molecular structure along with the density as described above, while enhancing the ratio of the polymer region, the ratio of the low-crystallinity component, and the ratio of the soluble fraction.

[0066]

[0067] Specifically, the polyethylene may have a molecular weight distribution (PDI, Mw / Mn) of 20 to 50. Preferably, the molecular weight distribution (Mw / Mn) of the polyethylene may be 20 or more, or 21 or more, or 22 or more, or 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.

[0068] 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 can be maintained and environmental stress crack resistance (ESCR) can be improved.

[0069] 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).

[0070] 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.

[0071] Specifically, a Waters PL-GPC220 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 (1,2,4-trichlorobenzene) containing 0.0125% butylated hydroxytoluene (BHT) using a GPC analyzer (PL-GP220) at 160 ℃ for 10 hours, 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, including 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.

[0072]

[0073] 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.

[0074] 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, environmental stress crack resistance (ESCR) can be improved along with excellent mechanical properties.

[0075]

[0076] 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.

[0077]

[0078] 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.

[0079]

[0080] 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.

[0081] [Chemical Formula 1]

[0082] (Cp 1 R a ) n (Cp 2R b )M 1 Z 1 3-n

[0083] In the above chemical formula 1,

[0084] M 1 It is a Group 4 transition metal;

[0085] Cp 1 and Cp 2 are respectively cyclopentadiennyl, and these are C 1-20 Substituted with or unsubstituted with hydrocarbons;

[0086] R a and R b are identical or different from each other, and each 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;

[0087] 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;

[0088] n is 1 or 0 and;

[0089] [Chemical Formula 2]

[0090]

[0091] In the above chemical formula 2,

[0092] C1 is any one of the ligands represented by the following chemical formulas 3 to 6, and

[0093] [Chemical Formula 3]

[0094]

[0095] [Chemical Formula 4]

[0096]

[0097] [Chemical Formula 5]

[0098]

[0099] [Chemical Formula 6]

[0100]

[0101] In the above chemical formulas 3 to 6,

[0102] 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

[0103] M is Ti, Zr, or Hf, and

[0104] Z is -O-, -S-, -NR7- or -PR7-, and

[0105] 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

[0106] 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

[0107] T is or And,

[0108] T1 is C, Si, Ge, Sn, or Pb, and

[0109] 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, C 8-40 alkynylaryl of, C 7-40 arylalkyl of, C8-40 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,

[0110] Y2 is C 2-30 Alkoxyalkyl, or C 7-40 It is an aryloxyalkyl, and

[0111] 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.

[0112]

[0113] Meanwhile, unless otherwise specifically limited in this specification, the following terms may be defined as follows.

[0114]

[0115] Halogens can be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

[0116]

[0117] 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 3-20Branched 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.

[0118]

[0119] 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.

[0120]

[0121] 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.

[0122]

[0123] 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.

[0124]

[0125] 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.

[0126]

[0127] 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.

[0128]

[0129] 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.

[0130]

[0131] 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.

[0132]

[0133] 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.

[0134]

[0135] 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.

[0136]

[0137] 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.

[0138]

[0139] 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.

[0140]

[0141] 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 10 Examples of groups connected to form an aromatic ring include pyrrolyl groups.

[0142]

[0143] In addition, group 4 transition metals include titanium (Ti), zirconium (Zr), hafnium (Hf), etc., but are not limited to these.

[0144]

[0145] 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.

[0146]

[0147] 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 7-20 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 is an arylalkyl, and the rest R a and R b At least one of them is C 2-20 It is an alkoxyalkyl.

[0148]

[0149] 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-ncan 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.

[0150]

[0151] 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 R a 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).

[0152]

[0153] 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.

[0154]

[0155]

[0156] 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) exist between the different ligands.

[0157]

[0158] More specifically, in the above chemical formula 2, M is Ti, Zr, or Hf, and more specifically, may be Ti.

[0159]

[0160] 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.

[0161]

[0162] Also, R5 and R6 each independently C 1-10 It is alkyl, and more specifically, both R5 and R6 can be methyl.

[0163]

[0164] 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.

[0165]

[0166] 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 7-30It 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.

[0167]

[0168] 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.

[0169]

[0170] 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.

[0171] 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.

[0172] 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 proportions of the polymer region, content of low-crystallinity components, and soluble fractions.

[0173] [Chemical Formula 2a]

[0174]

[0175] [Chemical Formula 2b]

[0176]

[0177] [Chemical Formula 2c]

[0178]

[0179] [Chemical Formula 2d]

[0180]

[0181] In the above chemical formulas 2a to 2d, R1 to R7, M, X1, X2, T1, Y1, and Y2 are as previously defined.

[0182]

[0183] 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 7-30Alkylaryl, 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.

[0184]

[0185] More specifically, specific examples of the second metallocene compound may include compounds having the following structures, but are not limited thereto:

[0186]

[0187] .

[0188]

[0189] 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.

[0190] 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.

[0191]

[0192] 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.

[0193]

[0194] 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.

[0195]

[0196] 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.

[0197]

[0198] 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.

[0199]

[0200] At this time, the polymerization temperature may be 25 ℃ to 500 ℃, preferably 25 ℃ to 200 ℃, more preferably 50 ℃ to 150 ℃. In addition, the polymerization pressure may be 1 Kgf / ㎠ to 100 Kgf / ㎠, preferably 1 Kgf / ㎠ to 50 Kgf / ㎠, more preferably 5 Kgf / ㎠ to 30 Kgf / ㎠.

[0201]

[0202] 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.

[0203]

[0204] 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.

[0205]

[0206] In particular, the polyethylene composition according to the present invention uses polyethylene in which the ratio of the polymer region, the content of low-crystallinity components, and the content of soluble fractions are all optimized by optimizing the molecular structure along with the density as described above. This improves environmental stress crack resistance (ESCR) while maintaining excellent mechanical properties when blended with recycled polyethylene, thereby ensuring excellent drop impact strength and environmental stress crack resistance comparable to that of virgin resin even when blended with recycled polyethylene.

[0207]

[0208] 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.

[0209] 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.

[0210]

[0211] 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 / cm³ 3 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 It may be less than.

[0212] 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 0.1 g / 10 min to 0.7 g / 10 min.

[0213] 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%).

[0214]

[0215] 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.

[0216]

[0217] 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.

[0218] 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%).

[0219] 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.

[0220] 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.

[0221] At this time, the measurement method for the density, ESCR, etc. 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.

[0222]

[0223] 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.

[0224]

[0225] <Example>

[0226] Manufacture of Polyethylene

[0227] Example 1-1

[0228] High-density new polyethylene was manufactured through a single slurry polymerization process as follows.

[0229] First, 15 kg / h of isobutane and 33 kg / h of ethylene were injected into a single slurry loop reactor, along with hydrogen at a flow rate of 300 g / h. 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 3.2 wt% relative to the ethylene input amount. At this time, the reactor was maintained between 90 and 95 ℃, and the pressure was 42 kg / cm². 3 The copolymerization process was carried out by maintaining the solvent, and then high-density virgin polyethylene (HDPE, Virgin polyethylene) in powder form was produced through a solvent removal facility and a dryer.

[0230] (1) (2)

[0231] (3)

[0232]

[0233]

[0234] Examples 1-2

[0235] High-density new polyethylene was prepared in the same manner as in Example 1-1, except that the hydrogen flow rate was changed to 330 g / h and the amount of 1-hexene added was changed to 2.8 wt%.

[0236]

[0237] Examples 1-3

[0238] High-density new polyethylene was prepared in the same manner as in Example 1-1, except that the hydrogen flow rate was changed to 330 g / h and the amount of 1-hexene added was changed to 4.0 wt%.

[0239]

[0240] Comparative Example 1-1

[0241] High-density new polyethylene was manufactured through a single slurry polymerization process as follows.

[0242] First, 15 kg / h of isobutane and 33 kg / h of ethylene were injected into a single slurry loop reactor, along with hydrogen at a flow rate of 220 g / h. Additionally, a catalyst (molar ratio of the first metallocene compound to the second metallocene compound = 2:1) in which the first metallocene compound (1) and the second metallocene compound (2) 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 1.5 wt% relative to the ethylene input amount. At this time, the reactor was maintained between 90 and 95 ℃, and the pressure was 42 kg / cm². 3 The copolymerization process was carried out by maintaining the solvent, and then high-density virgin polyethylene (HDPE, Virgin polyethylene) in powder form was produced through a solvent removal facility and a dryer.

[0243] (1) (2)

[0244]

[0245] Comparative Example 1-2

[0246] In Comparative Example 1-1, high-density new polyethylene was prepared in the same manner as Comparative Example 1, except that the hydrogen flow rate was changed to 240 g / h and the amount of 1-hexene added was changed to 1.0 wt%.

[0247]

[0248] Comparative Examples 1-3

[0249] In Comparative Example 1-1, high-density new polyethylene was produced in the same manner as Comparative Example 1, except that the hydrogen flow rate was changed to 160 g / h and the amount of 1-hexene added was changed to 0.8 wt%.

[0250]

[0251] Comparative Examples 1-4

[0252] In Comparative Example 1-1, high-density new polyethylene was produced in the same manner as Comparative Example 1, except that the hydrogen flow rate was changed to 300 g / h and the amount of 1-hexene added was changed to 2.2 wt%.

[0253]

[0254] <Preparation of Polyethylene Composition>

[0255] Example 2-1

[0256] 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.

[0257] High-density polyethylene and recycled polyethylene are as follows:

[0258] 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.

[0259] 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 to 50 hours.

[0260]

[0261] Example 2-2

[0262] 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.

[0263]

[0264] Examples 2-3

[0265] 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.

[0266]

[0267] Comparative Example 2-1

[0268] 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.

[0269]

[0270] Comparative Example 2-2

[0271] 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.

[0272]

[0273] Comparative Example 2-3

[0274] 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.

[0275]

[0276] Comparative Example 2-4

[0277] A polyethylene composition was prepared in the same manner as in Example 2-1, except that polyethylene prepared in Comparative Example 1-4 was used instead of polyethylene prepared in Example 1-1 using new polyethylene.

[0278]

[0279] <Experimental Example: Evaluation of Physical Properties of Polyethylene>

[0280] The physical properties of the polyethylene or polyethylene compositions of the examples and comparative examples were evaluated in the following manner, and the measurement results are shown in Tables 1 and 2 below, respectively.

[0281]

[0282] (1) Density

[0283] Density of polyethylene at 23°C according to ASTM D 1505 (g / cm³) 3 ) was measured.

[0284]

[0285] (2) Weight average molecular weight (Mw), molecular weight distribution (PDI, Mw / Mn), and log Mw≥5.5 content

[0286] 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.

[0287] 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.

[0288] In the manner described above, gel permeation chromatography (GPC, manufactured by Water) was used to analyze the y-axis (dw / dlogMw) and x-axis (logMw) curves, and the region where the log Mw value was 5.5 or higher (LogMw≥5.5) was expressed as a percentile.

[0289]

[0290] (3) Content of low-crystallinity fraction and soluble fraction

[0291] Cross-fraction chromatography (CFC) analysis was performed on the polyethylene of the above examples and comparative examples in the following manner.

[0292] - Analysis Equipment: Polymer Char CFC - 7890B (G3440D)

[0293] (Detector: Integrated Detector IR5 MCT)

[0294] - Sample preparation and input: 32 mg of polyethylene from the above example or comparative example was placed in a 10 mL vial and placed in an autosampler. After adding 8 mL of 1,2,4-trichlorobenzene (TCB), the sample was dissolved at 160°C for 90 minutes and stabilized at 140°C for 20 minutes. After nitrogen purge, the sample was extracted and loaded onto a temperature rising elution fractionation column (TREF column).

[0295] - Crystallization: After setting the temperature of the sample loaded into the TREF column to 140℃, it was cooled from 140℃ to 35℃ at a rate of 0.5℃ / min and maintained for 15 minutes.

[0296] The detailed conditions for the above stabilization and crystallization are as follows:

[0297]

[0298]

[0299] - Temperature-Increased Elution Fraction (TREF) Analysis: The previously crystallized sample was heated from 35 ℃ to 120 ℃ at a rate of 20 ℃ / min to the fraction temperature below, then fixed, and the concentrations of the fractions eluted at that temperature were measured for 5 minutes. A TREF graph was derived from these concentration measurements.

[0300] From the TREF graph, based on the total weight of the total elution fraction, the content ratio of the low-crystallinity fraction eluted in the elution temperature range of 60 to 90 ℃ and the content of the soluble fraction eluted in the elution temperature range of 20 to 30 ℃ were each calculated.

[0301] < fraction temperature >

[0302] 35℃ / 40℃ / 43℃ / 46℃ / 49℃ / 52℃ / 55℃ / 58℃ / 61℃ / 64℃ / 67℃ / 70℃ / 73℃ / 76℃ / 79℃ / 82℃ / 85℃ / 88℃ / 91℃ / 94℃ / 97℃ / 100℃ / 105℃ / 120℃

[0303]

[0304] (4) Environmental stress crack resistance (ESCR)

[0305] 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.

[0306]

[0307] (5) Falling impact

[0308] A disc was manufactured based on a polyethylene resin composition (PCR Compound) using the following method.

[0309] More specifically, the disc was manufactured using an injection molding machine, and after setting the temperature gradient to 210–230 ℃, a polyethylene resin composition was injected and injected under conditions of an injection speed of 11 mm / s and a holding pressure of 450 bar to produce a disc with a diameter of 50 mm and a thickness of 2 mm.

[0310] For the manufactured disc, the drop impact strength corresponding to the face impact strength was measured using the ASTM D 3763 method. Specifically, using the Instron 9440 (Impact Drop Tower) product (Impact energy 4.2 J, Impact velocity 4.55 m / s, Temperature 5 ℃), the disc was fixed and a weight was dropped to measure the number of times a crack occurred.

[0311]

[0312] (6) Melt Index (MI) 2.16 )

[0313] It was measured according to ASTM D 1238, 190 ℃, 2.16 kg.

[0314]

[0315] Density (g / cm³) 3 )LogMw≥5.5(%) Low-crystallinity fraction (%) eluted at 60 to 90 ℃ temperature Soluble fraction (%) eluted at 20 to 30 ℃ temperature Molecular weight distribution Mw(g / mol) MI(g / 10min) Example 1-10.9460 14.66 5.02.32 2.4148 1000.55 Example 1-20.9468 13.16 4.52 2.12 3.8143 3000.63 Example 1-30.9445 12.57 1.52 2.72 1.5128 1000.71 Comparative Example 1-10.9463 14.86 4.51.32 0.1156 1000.52 Comparative Example 1-20.946313.555.52.022.81397000.51 Comparative Example 1-30.947417.361.42.018.01865000.18 Comparative Example 1-40.942910.269.12.414.61130001.08

[0316] Density (g / cm³) 3 Drop Impact (Times) ESCR (Time) Example 2-10.95 238 270 Example 2-20.95 249 240 Example 2-30.95 219 250 Comparative Example 2-10.95 237 195 Comparative Example 2-20.95 237 185 Comparative Example 2-30.95 245 220 Comparative Example 2-40.95 2010 180

[0317] Referring to Tables 1 and 2 above, it can be seen that when using the new polyethylene of Examples 1-1 to 1-3, in which the molecular structure along with density is optimized according to the present invention to optimize the ratio of the polymer region, the content of the low-crystallinity component, and the soluble fraction, mechanical properties such as excellent drop impact strength are maintained when combined with recycled polyethylene (PCW PE), and at the same time, the environmental stress crack resistance (ESCR) can be significantly improved to over 200 hours.

Claims

1. Polyethylene satisfying (1) to (4) below: (1) Density of 0.944 g / cm³ measured according to ASTM D 1505, 23 ℃ 3 more; (2) 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 greater is 15% or less of the total integral value; (3) When analyzed by cross-fractionation chromatography (CFC), the content ratio of the low-crystallinity fraction eluted at a temperature of 60 to 90 ℃ is 60% or more of the total weight of the eluted fraction; (4) When analyzed by cross-fractionation chromatography (CFC), the content ratio of the soluble fraction eluted at a temperature of 20 to 30 ℃ is 2.0% or more of the total weight of the eluted fraction.

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 10 to 15% of the total integral value. Polyethylene.

5. In Paragraph 1, The above polyethylene is such that, when analyzed by cross-fractionation chromatography (CFC), the content ratio of the low-crystallinity fraction eluted at a temperature of 60 to 90 ℃ is 60 to 80% of the total weight of the eluted fraction, Polyethylene.

6. In Paragraph 1, The above polyethylene has a content ratio of a soluble fraction eluted at a temperature of 20 to 30 ℃ during cross-fractionation chromatography (CFC) analysis of 2.0 to 3.0% of the total weight of the eluted fraction, Polyethylene.

7. 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 6, Polyethylene composition.

8. In Paragraph 7, 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.

9. In Paragraph 7, The above recycled polyethylene has a density of 0.940 to 0.960 g / cm³ as measured according to ASTM D 1505, 23 ℃. 3 person, Polyethylene composition.

10. In Paragraph 7, The above recycled polyethylene has an environmental stress crack resistance (ESCR) of 40 to 60 hours as measured according to ASTM D 1693 (Condition B, F50, Igepal 10%), Polyethylene composition.

11. In Paragraph 7, 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.

12. In Paragraph 7, The above polyethylene composition has an environmental stress crack resistance (ESCR) of 200 hours or more as measured according to ASTM D 1693 (Condition B, F50, Igepal 10%), Polyethylene composition.

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