Polyethylene composition and articles made therefrom

Abstract

The present invention relates to a polyethylene composition comprising polyethylene having excellent balance between processability and mechanical property. Said polyethylene composition has significantly improved polymer melt strength and also shows good shear sensitivity behavior while also providing improved mechanical property. These are the results of the polymer which is characterized in the molecular weight distribution and the short chain branching distribution, as shown in this present invention, due to synergistic behavior of the dual catalyst system in which said polyethylene can be prepared using single polymerization reactor.

Description

[0001] Polyethylene composition and articles made therefrom

[0002] Technical Field

[0003] The present invention relates to the field of science, in particular, to the polyethylene composition and the articles comprising polyethylene composition.

[0004] Background Art

[0005] The olefin-based polymer especially the ethylene-based polymer or polyethylene can be utilized in many products. The characters and properties of said polyethylene can be adjusted or differentiated to be suitable to different uses with important factors in polymerization process and catalyst used in said polymerization process.

[0006] At present, the development of polyethylene to be suitable in several uses focuses on the development of several characters and properties of polyethylene together. This can be done by cascade polymerization process such as solution polymerization process that uses a cascade of 2 reactors by Dow Chemical, or slurry polymerization process that uses loop reactor followed by gas phase polymerization process by Borealis. Optionally, this can be done by the selection of catalyst system in several aspects such as a multisite catalyst system or a mixed catalyst system comprising two or more of different polymerization catalysts, which might be Ziegler-Natta catalyst or metallocene catalyst, in which each catalyst or each site would produce polyethylene having average molar mass that is different from polyethylene produced by the other catalyst or the other site.

[0007] The development of polyethylene that focuses on the development of several properties of polyethylene by the selection of catalyst system has been disclosed in the following documents.

[0008] Patent document US20210147661A1 discloses polyethylene having low molecular weight fraction having low concentration of comonomer short chain branches (SCBs) while having high molecular weight fraction having high concentration of comonomer short chain branches. The ratio of a number of short chains branches at Z average molecular weight (Mz) to at numberaverage molecular weight (Mn) is in a range from 11.5 to 22. Said polyethylene is prepared by a dual catalyst system comprising a unbridged metallocene compound with an indenyl group having at least one halogen-substituted hydrocarbyl substituent with at least two halogen atoms and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group. Said polyethylene has an improved environmental stress crack resistance (ESCR), an improved slow crack growth resistance, and an improved draw ratio.

[0009] Patent document W02007008361A1 discloses polyethylene comprising low molecular weight polyethylene component and high molecular weight polyethylene component. Said low molecular weight polyethylene component has higher concentration of long chain branches (LCBs) than high molecular weight polyethylene component. The low molecular weight polyethylene component is selected from polyethylene prepared by bridged indenoindolyl ligandcontaining single-site catalyst. The high molecular weight polyethylene component is selected from polyethylene prepared by non-bridged indenoindolyl ligand-containing single-site catalyst. Said polyethylene has good mechanical property and processability.

[0010] Patent document W02002074816A2 discloses polyethylene comprising low molecular weight component and high molecular weight component that have substantially equal amounts of comonomer incorporation. Said polyethylene is prepared using at least 2 catalysts in polymerization process. It has been found that said polyethylene has good polymer melt strength and processability, as well as optical property that is similar to low density polyethylene (LDPE), and good mechanical property when comparing with low density polyethylene. Patent document US20210309841A1 discloses polyethylene comprising low molecular weight component having significant amount of long chain branches and high molecular weight component having substantially no long chain branch. Said polyethylene is prepared by a dual catalyst system comprising a single atom bridged metallocene compound with an indenyl group and a cyclopentadienyl group, and an unbridged hafnium metallocene compound with two cyclopentadienyl groups. Said polyethylene has good strength, good toughness, and good tear strength, while maintaining polymer melt strength and film bubble stability.

[0011] Patent document US20170145123A1 discloses polyethylene having low density, high molecular weight, and broad molecular weight distribution, as well as having the majority of the long chain branches in the low molecular weight component and the majority of the short chain branches in the high molecular weight component. Said polyethylene is prepared by a dual metallocene catalyst system. The film prepared from said polyethylene has improved impact resistance and puncture resistance.

[0012] Patent document US20190233551A1 discloses polyethylene having a reverse short chain branching distribution that has a number of short chain branches at Z average molecular weight (Mz) greater than at number-average molecular weight (Mn). Said polyethylene is prepared by the catalyst system comprising half-metallocene titanium compound, bridged metallocene compound, activator, and co-catalyst. Said polyethylene has good strength and toughness as well as good processability and shear thinning. Especially, the blown film prepared from said polyethylene has good dart impact, tear strength, and optical properties, as well as can be processed more easily and has better polymer melt strength than traditional metallocene catalyst-prepared linear low density polyethylene resin. It can be seen that, the selection of catalyst system has an impact in the difference of the comonomer incorporation, resulting in difference in a number of side chains formed from the monomer incorporation and the distribution of side chains that is called short chain branching distribution (SCBD). These affect the crystallization behavior of polyethylene, especially mechanical property. While the flow property, which affects the processability, although mainly rely on the molar mass and the molar mass distribution, the short chain branching distribution also affects the flow property and the processability. However, the balanced combination between good processability and good mechanical property is rarely found from the view point of the possible combination, in which the previously disclosed inventions are a part only.

[0013] Therefore, the present invention provides the polyethylene composition comprising polyethylene having excellent balance between processability and mechanical property. In another aspect, said polyethylene is characterized in the molecular weight distribution and short chain branching distribution and is prepared by the polymerization process using single reactor with a dual catalyst system comprising an unbridged Group IV transition metal based metallocene compound and a bridged Group IV transition metal based metallocene compound.

[0014] Summary of Invention

[0015] The present invention aims to provide a polyethylene composition comprising polyethylene having excellent balance between processability and mechanical property, wherein said polyethylene comprises ethylene monomer and C3-C20 a-olefin comonomer in an amount from 0.1 to 35 % by weight, and wherein said polyethylene has the following properties:

[0016] - a density in a range from 0.910 to 0.935 g / cm3;

[0017] - a melt flow rate (MFR) in a range from 0.1 to 100 g / 10 min (as measured according to

[0018] ASTM D1238 at temperature of 190 °C and load of 2.16 kg); - a molecular weight distribution (Mw / Mn) from 3 to 50;

[0019] - a gpcBR index of equal to or greater than 0.3;

[0020] - a multimodality characteristic showing in a chromatogram of gel permeation chromatography (GPC), wherein said chromatogram is subjected to a deconvolution using Schulz- Flory distribution and comprises: a) 30 to 55 %, comparing to total area of the chromatogram, for a first component having the weight-average molecular weight (Mw) from 20,000 to 75,000 g / mol; b) 35 to 55 %, comparing to total area of the chromatogram, for a second component having the weight-average molecular weight from 80,000 to 200,000 g / mol; and c) 5 to 20 %, comparing to total area of the chromatogram, for a third component having the weight-average molecular weight from 300,000 to 800,000 g / mol; and

[0021] - a SCBiogM2 / SCBiogMi of equal to or less than 1, SCBiogMi of greater than 10, and SCBiogM3 / SCBiogM2 of greater than or equal to 1, wherein SCBiogMi is a number of short chain branches (SCB) per 1,000 total carbon atoms of the polyethylene measured at logMl, SCBiogM2 is the number of short chain branches per 1 ,000 total carbon atoms of the polyethylene measured at logM2, and SCBiogM3 is the number of short chain branches per 1,000 total carbon atoms of the polyethylene measured at logM3, and wherein logMl, logM2, and logM3 is the logarithm of the molecular weight in the gel permeation chromatography analysis equipped with infrared detector (GPC-IR) at 4, 5, and 5.5, respectively.

[0022] Brief Description of the Drawings

[0023] Figure 1 shows the chromatogram of the gel permeation chromatography (GPC) of the sample according to the invention 1 compared to the comparative samples 1 and 2, wherein the relation between differential weight fraction with respect to logarithm of molecular weight (dWf / dLogM) and logarithm of molecular weight (LogM), and the relation between number of short chain branches per 1,000 total carbon atoms (SCB / 10000TC) and logarithm of molecular weight (LogM) are shown.

[0024] Figure 2 shows the chromatogram of the gel permeation chromatography (GPC) of the sample according to the invention 1 compared to the comparative samples 3, 4, 5, and 6, wherein the relation between differential weight fraction with respect to logarithm of molecular weight (dWf / dLogM) and logarithm of molecular weight (LogM), and the relation between number of the short chain branches pre 1,000 total carbon atoms (SCB / 10000TC) and logarithm of molecular weight (LogM) are shown.

[0025] Figure 3 shows the chromatogram of the gel permeation chromatography (GPC) of the sample according to the invention 1, wherein said chromatogram is subjected to the deconvolution using Schulz-Flory distribution, in which the x-axis of said subjected chromatogram represents logarithm of molecular weight (LogMW) and the y-axis of said subjected chromatogram represents the proportion of logarithm of molecular weight (W ogMw).

[0026] Figure 4 shows the chromatogram of the cross-fractionation chromatography (CFC) of the sample according to the invention 1, wherein the graph with solid line represents the relation between differential weight with respect to temperature (dW / dT) and fractionation temperature in unit of degree Celsius (°C), the graph with dot line represents the relation between logarithm of molecular weight (LogM) and fractionation temperature in unit of degree Celsius (°C), and the graph with dash line represents the relation between cumulative weight percentage (sum weight) and fractionation temperature in unit of degree Celsius (°C).

[0027] Figure 5 shows the chromatogram of the cross-fractionation chromatography (CFC) of the comparative sample 5, wherein the graph with solid line represents the relation between differential weight with respect to temperature (dW / dT) and fractionation temperature in unit of degree Celsius (°C), the graph with dot line represents the relation between logarithm of molecular weight (LogM) and fractionation temperature in unit of degree Celsius (°C), and the graph with dash line represents the relation between cumulative weight percentage (sum weight) and fractionation temperature in unit of degree Celsius (°C).

[0028] Figure 6 shows the chromatogram of the cross-fractionation chromatography (CFC) of the comparative sample 6, wherein the graph with solid line represents the relation between differential weight with respect to temperature (dW / dT) and fractionation temperature in unit of degree Celsius (°C), the graph with dot line represents the relation between logarithm of molecular weight (LogM) and fractionation temperature in unit of degree Celsius (°C), and the graph with dash line represents the relation between cumulative weight percentage (sum weight) and fractionation temperature in unit of degree Celsius (°C).

[0029] Figure 7 shows the shear viscosity at the temperature of 190 °C, that is a function of shear rate, of the sample according to the invention 1 compared with the comparative samples 5 and 6.

[0030] Description of the Invention

[0031] The present invention relates to the polyethylene composition comprising polyethylene having excellent balance between processability and mechanical property, wherein said polyethylene is characterized in the molecular weight distribution and short chain branching distribution and is prepared by the polymerization process using single reactor with the dual catalyst system comprising the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound, which will be described in the following aspects of the invention. Any aspect being demonstrated herein also means to include the application to other aspects of this invention unless stated otherwise.

[0032] Technical terms or scientific terms used herein have definitions as understood by an ordinary person skilled in the art unless stated otherwise.

[0033] Any tools, equipment, methods, or chemicals named herein mean tools, equipment, methods, or chemicals being operated or used commonly by those person skilled in the art unless stated otherwise that they are tools, equipment, methods, or chemicals specific only in this invention.

[0034] Use of singular noun or singular pronoun with “comprising” in claims or specification means “one” and also including “one or more”, “at least one”, and “one or more than one”.

[0035] All compositions and / or methods disclosed and claims in this application are intended to cover embodiments from any operation, performance, modification, or adjustment any factors without any experiment that significantly different from this invention, and obtain with object with utility and resulted as same as the present embodiment according to person ordinary skilled in the art although without specifically stated in claims. Therefore, substitutable or similar object to the present embodiment, including any minor modification or adjustment that can be apparent to person skilled in the art should be construed as remains in spirit, scope, and concept of invention as appeared in appended claims.

[0036] Throughout this application, term “about” means any number that appeared or expressed herein that could be varied or deviated from any error of equipment, method, or personal using said equipment or method, including variations or deviations occurred from changes in reaction conditions of uncontrollable factors such as humidity and temperature. Definitions

[0037] “Polyethylene” or “ethylene-based polymer” means the polymer comprising more than 50 % by mole of units derived from ethylene monomer. This includes homopolymer or copolymer of polyethylene. The common forms of polyethylene known in the art include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), single-site catalyzed linear low density polyethylene including both linear and substantially linear low density resins (m-LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

[0038] “Catalyst system” means one or more polymerization catalysts and may further comprise an activator, a support / a carrier, or any combination thereof. The term “catalyst” and “catalyst system” can be used interchangeably herein.

[0039] “Dual catalyst system” means the catalyst system comprising 2 types or 2 polymerization catalysts, wherein the polymerization catalysts may be same or different type, and may further comprise activator, support / carrier, or any combination thereof.

[0040] “Support” means the support or carrier that supports, has a deposit of, has an attachment of, has a contact of, bonds with, has an incorporation within of, or has an adsorption or absorption of one or more compounds, wherein one or more compounds are supported by, are supported on, are deposited on, are attached on or with, contact with, bond with, are incorporated within, are adsorbed or absorbed in, or on, the support or carrier. This may be called as “on the co-support”.

[0041] Hereafter, invention embodiments are shown without any purpose to limit any scope of the invention. The present invention relates to the polyethylene composition comprising polyethylene comprising ethylene monomer and C3-C20 a-olefin comonomer in the amount from 0.1 to 35 % by weight, wherein said polyethylene has the following properties:

[0042] - the density in the range from 0.910 to 0.935 g / cm3;

[0043] - the melt flow rate (MFR) in the range from 0.1 to 100 g / 10 min (as measured according to ASTM D 1238 at temperature of 190 °C and load of 2.16 kg);

[0044] - the molecular weight distribution (Mw / Mn) from 3 to 50;

[0045] - the gpcBR index of equal to or greater than 0.3;

[0046] - the multimodality characteristic showing in the chromatogram of gel permeation chromatography (GPC) wherein said chromatogram is subjected to the deconvolution using Schulz-Flory distribution and comprises: a) 30 to 55 %, comparing to total area of the chromatogram, for the first component having the weight-average molecular weight (Mw) from 20,000 to 75,000 g / mol; b) 35 to 55 %, comparing to total area of the chromatogram, for the second component having the weight-average molecular weight from 80,000 to 200,000 g / mol; and c) 5 to 20 %, comparing to total area of the chromatogram, for the third component having the weight-average molecular weight from 300,000 to 800,000 g / mol; and

[0047] - the SCBiogM2 / SCBiogMi of equal to or less than 1, SCBiogMi of greater than 10, and SCBiogM3 / SCBiogM2 of greater than or equal to 1, wherein SCBiogMi is the number of short chain branches (SCB) per 1,000 total carbon atoms of the polyethylene measured at logMl, SCBiogM2 is the number of short chain branches per 1 ,000 total carbon atoms of the polyethylene measured at logM2, and SCBiogM3 is the number of short chain branches per 1,000 total carbon atoms of the polyethylene measured at logM3, and wherein logMl, logM2, and logM3 is the logarithm of the molecular weight in the gel permeation chromatography analysis equipped with infrared detector (GPC-IR) at 4, 5, and 5.5, respectively.

[0048] In one aspect of the invention, said polyethylene has the density in the range from 0.910 to 0.930 g / cm3, preferably in the range from 0.915 to 0.925 g / cm3, most preferably in the range from 0.915 to 0.920 g / cm3.

[0049] In one aspect of the invention, said polyethylene has the melt flow rate in the range from 0.1 to 50 g / 10 min (as measured according to ASTM D1238 at temperature of 190 °C and load of 2.16 kg), preferably from 0.1 to 20 g / 10 min, most preferably from 0.1 to 10 g / 10 min.

[0050] In one aspect of the invention, said polyethylene has the multimodality characteristic showing in the chromatogram of gel permeation chromatography, wherein said chromatogram is subjected to the deconvolution using Schulz-Flory distribution and comprises: a) 30 to 55 %, comparing to total area of the chromatogram, for the first component having the weight-average molecular weight (Mw) from 35,000 to 70,000 g / mol, preferably from 40,000 to 65,000 g / mol; b) 35 to 55 %, comparing to total area of the chromatogram, for the second component having the weight-average molecular weight from 80,000 to 180,000 g / mol, preferably from 100,000 to 150,000 g / mol; and c) 5 to 20 %, comparing to total area of the chromatogram, for the third component having the weight-average molecular weight from 350,000 to 600,000 g / mol, preferably from 400,000 to 550,000 g / mol.

[0051] In one aspect of the invention, said polyethylene has the gpcBR index of equal to or greater than 0.3 but less than 1, preferably the gpcBR index of equal to or greater than 0.3 but less than or equal to 0.7. In one aspect of the invention, said polyethylene has SCBiogM2 / SCBiogMi of greater than or equal to 0.7 but less than or equal to 1, preferably SCBiogM2 / SCBiogMi of greater than or equal to 0.7 but less than 1, most preferably greater than 0.7 but less than 1.

[0052] In one aspect of the invention, said polyethylene has SCBiogMi of greater than 10 but less than 30, preferably SCBiogMi of greater than 10 but less than 25, most preferably SCBiogMi of greater than 10 but less than 20.

[0053] In one aspect of the invention, said polyethylene has SCBiogM3 / SCBiogM2 of greater than 1, preferably SCBiogM3 / SCBiogM2 of greater than 1 but less than or equal to 1.3.

[0054] In one aspect of the invention, said polyethylene has Mwl / Mw2 of less than 1, wherein Mwl / Mw2 is the ratio of the weight-average molecular weight (Mw) for the first half of the temperature rising elution fractionation (TREF) curve from the cross-fractionation chromatography (CFC) to the weight-average molecular weight for the second half of the temperature rising elution fractionation curve, preferably Mwl / Mw2 of greater than or equal to 0.5 but less than 1, most preferably Mwl / Mw2 of greater than or equal to 0.7 but less than or equal to 0.95.

[0055] In one aspect of the invention, said polyethylene has Twl-Tw2 of from -16 to -38, wherein Twl-Tw2 is the difference between the weight average elution temperature (Tw) for the first half of the temperature rising elution fractionation curve and the weight average elution temperature for the second half of the temperature rising elution fractionation curve, preferably Twl-Tw2 of from -20 to -35, most preferably Twl-Tw2 of from -20 to -30.

[0056] In one aspect of the invention, said polyethylene has the multimodality characteristic showing in the elution profile from the cross-fractionation chromatography (CFC), comprising: a) 10 to 30 % by weight of the fraction eluted in the temperature range of lower than 60 °C has the weight-average molecular weight from 40,000 to 120,000 g / mol, preferably the weightaverage molecular weight from 60,000 to 100,000 g / mol; b) 50 to 80 % by weight of the fraction eluted in the temperature range of from 60 to 90 °C has the weight- average molecular weight from 100,000 to 200,000 g / mol, preferably the weightaverage molecular weight from 120,000 to 160,000 g / mol; and c) 5 to 25 % by weight of the fraction eluted in the temperature range of higher than 90 °C has the weight- average molecular weight from 100,000 to 200,000 g / mol, preferably the weightaverage molecular weight from 120,000 to 160,000 g / mol.

[0057] In one aspect of the invention, said polyethylene has the multimodality characteristic showing in the elution profile from the cross-fractionation chromatography (CFC), comprising: a) 15 to 25 % by weight of the fraction eluted in the temperature range of lower than 60 °C has the weight-average molecular weight from 40,000 to 120,000 g / mol, preferably the weightaverage molecular weight from 60,000 to 100,000 g / mol; b) 60 to 75 % by weight of the fraction eluted in the temperature range of from 60 to 90 °C has the weight- average molecular weight from 100,000 to 200,000 g / mol, preferably the weightaverage molecular weight from 120,000 to 160,000 g / mol; and c) 10 to 25 % by weight of the fraction eluted in the temperature range of higher than 90 °C has the weight-average molecular weight from 100,000 to 200,000 g / mol, preferably the weight-average molecular weight from 120,000 to 160,000 g / mol.

[0058] In one aspect of the invention, said polyethylene has T75-T25 of from 20 to 30, wherein the T75 and T25 are the temperatures at which 75 % and 25 %, respectively, of the polymer is eluted from the temperature rising elution fractionation (TREF) analysis. In one aspect of the invention, said polyethylene has the composition distribution breadth index (CDBI) in the range from 35 to 55 %, preferably from 40 to 50 %.

[0059] In one aspect of the invention, said polyethylene has the weight-average molecular weight (Mw) analyzed by gel permeation chromatography (GPC) of from 80,000 to 300,000 g / mol, preferably from 80,000 to 200,000 g / mol, most preferably from 100,000 to 200,000 g / mol.

[0060] In one aspect of the invention, said polyethylene has the number-average molecular weight (Mn) analyzed by gel permeation chromatography (GPC) of from 15,000 to 35,000 g / mol, preferably from 20,000 to 35,000 g / mol.

[0061] In one aspect of the invention, said polyethylene has the Z average molecular weight (Mz) analyzed by gel permeation chromatography (GPC) of from 300,000 to 600,000 g / mol, preferably from 300,000 to 550,000 g / mol, most preferably from 350,000 to 500,000 g / mol.

[0062] In one aspect of the invention, said polyethylene has the molecular weight distribution (Mw / Mn) or Mw / Mn of from 3 to 30, preferably from 3 to 20, more preferably from 3 to 15, and most preferably from 3 to 10.

[0063] In one aspect of the invention, said polyethylene has the Z average molecular weight to the number-average molecular weight (Mz / Mn) of from 5 to 40, preferably from 5 to 30, most preferably from 10 to 20.

[0064] In one aspect of the invention, said polyethylene has the Z average molecular weight to the weight-average molecular weight (Mz / Mw) of from 2 to 10, preferably from 2 to 5.

[0065] In one aspect of the invention, said polyethylene had the bulk number of short chain branches per 1,000 total carbon atoms (bulk SCB / 1000TC) in the range from 5 to 25, preferably from 10 to 20. In one aspect of the invention, said polyethylene has the polymer melt strength of equal to or greater than 10 cN, preferably the polymer melt strength of greater than 10 cN but less than 50 cN, more preferably the polymer melt strength of greater than 10 but less than 30 cN, most preferably the polymer melt strength of greater than 10 but less than 25 cN.

[0066] In one aspect of the invention, C3-C20 a-olefin comonomer is C3-C10 a-olefin comonomer. Preferably, it is selected from 1 -hexene, 1 -octene, 1 -decene, or mixture of said a- olefin comonomers. Most preferably, C3-C20 a-olefin comonomer is 1-hexene.

[0067] In one aspect of the invention, the amount of C3-C20 a-olefin comonomer is from 0.1 to 30 % by weight, preferably from 1 to 20 % by weight, most preferably from 1 to 15 % by weight.

[0068] In one aspect of the invention, said polyethylene is prepared by polymerization process using single reactor with the dual catalyst system comprising the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound.

[0069] In one aspect of the invention, said dual catalyst system comprising the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound is supported on the co-support, wherein said co-support is selected from inorganic oxides including oxides of Group 2, 3, 4, 5, 13, or 14 metals or magnesium chloride. Preferably, said inorganic oxide may be selected from but not limited to silica, alumina, magnesia, titania, zirconia, montmorillonite, zeolite, silica-chromium, silica-alumina, silica-titania, silica- magnesia, or mixture thereof.

[0070] In one aspect of the invention, the Group IV transition metal is selected from hafnium, titanium, or zirconium, preferably titanium or zirconium. In one aspect of the invention, the weight proportion of the bridged Group IV transition metal based metallocene compound is in the range from 20 to 80 % comparing to the total weight of the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound, preferably in the range from 40 to 80 % comparing to the total weight of the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound.

[0071] In one aspect of the invention, said unbridged Group IV transition metal based metallocene compound is the unbridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand as shown in structure 1 :

[0072] Structure 1 wherein said cyclopentadienyl ligand may have substituent or may not have substituent, wherein Rl, R2, R3, R4, R5, R'l, R'2, R'3, R'4, and R'5 substituents are independently selected from, but not limited to, hydrogen or alkyl group; or any two adjacent groups selected from said Rl, R2, R3, R4, R5, R'l, R'2, R'3, R'4, and R'5 substituents may be joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, optionally wherein said aromatic ring may be substituted by one or more groups, whereas if there are remaining Rl, R2, R3, R4, R5, R'l, R'2, R'3, R'4, or R'5 substituents that are not joined together, said remaining substituents that are not joined together are independently selected from hydrogen or alkyl group; preferably said Rl, R2, R3, R4, R5, R'l, R'2, R'3, R'4, and R'5 substituents are independently selected from hydrogen or alkyl group selected from methyl group, ethyl group, propyl group, and butyl group, and wherein M is the Group IV transition metal selected from hafnium, titanium, or zirconium, preferably titanium or zirconium.

[0073] In one aspect of the invention, said bridged Group IV transition metal based metallocene compound is selected from, but not limited to, the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand, or the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and nitrogen.

[0074] In one aspect of the invention, said bridged Group IV transition metal based metallocene compound is the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand as shown in structure 2:

[0075] Structure 2 wherein said cyclopentadienyl ligand may have substituent or may not have substituent, wherein Rl, R2, R3, and R4 substituents are independently selected from, but not limited to, hydrogen or alkyl group; or any two adjacent groups selected from said Rl, R2, R3, and R4 substituents may be joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, optionally wherein said aromatic ring may be substituted by one or more groups, whereas if there are remaining Rl, R2, R3, or R4 substituents that are not joined together, said remaining substituents that are not joined together are independently selected from hydrogen or alkyl group; preferably said Rl, R2, R3, and R4 substituents are independently selected from hydrogen or alkyl group selected from methyl group, ethyl group, propyl group, and butyl group, wherein R’ l, R’2, R’3, and R’4 substituents are independently selected from, but not limited to, hydrogen or alkyl group; or any two adjacent groups selected from said R’ l, R’2, R’3, and R’4 substituents may be joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, optionally wherein said aromatic ring may be substituted by one or more groups selected from hydrogen, alkyl group, cycloalkyl group, aryl group, or arylalkyl group, whereas if there are remaining R’l, R’2, R’3, or R’4 substituents that are not joined together, said remaining substituents that are not joined together are independently selected from hydrogen or alkyl group; preferably any two adjacent groups of substituents selected from R’l, R’2, R’3, and R’4 are joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, wherein said aromatic ring is substituted by one or more groups selected from hydrogen, alkyl group, cycloalkyl group, aryl group, or arylalkyl group, most preferably said aromatic ring is substituted by arylalkyl group, whereas remaining R’l, R’2, R’3, or R’4 substituents that are not joined together are independently selected from hydrogen or alkyl group, wherein M is the Group IV transition metal selected from hafnium, titanium, or zirconium, preferably titanium or zirconium, wherein X-bridging position is selected from, but not limited to, carbon or silicon, preferably silicon, and wherein the bridging position has R5 and R6 substituents selected from, but not limited to, hydrogen or alkyl group, preferably alkyl group selected from methyl group, ethyl group, propyl group, or butyl group.

[0076] In one aspect of the invention, said bridged Group IV transition metal based metallocene compound is the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and nitrogen as shown in structure 3:

[0077] Structure 3 wherein said cyclopentadienyl ligand may have substituent or may not have substituent, wherein Rl, R2, R3, and R4 substituents are independently selected from, but not limited to, hydrogen or alkyl group; or any two adjacent groups selected from said Rl, R2,

[0078] R3, and R4 substituents may be joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, optionally wherein said aromatic ring may be substituted by one or more groups, whereas if there are remaining Rl, R2, R3, or R4 substituents that are not joined together, said remaining substituents that are not joined together are independently selected from hydrogen or alkyl group; preferably said Rl, R2, R3, and R4 substituents are independently selected from hydrogen or alkyl group selected from methyl group, ethyl group, propyl group, or butyl group, wherein said nitrogen may have substituent or may not have substituent, wherein R’ substituent is selected from, but not limited to, hydrogen, alkyl group, cycloalkyl group, aryl group, or arylalkyl group, preferably alkyl group selected from methyl group, ethyl group, propyl group, or butyl group, wherein M is the Group IV transition metal selected from hafnium, titanium, or zirconium, preferably titanium or zirconium, wherein X-bridging position is selected from, but not limited to, carbon or silicon, preferably silicon, and wherein the bridging position has R5 and R6 substituents selected from, but not limited to, hydrogen or alkyl group, preferably alkyl group selected from methyl group, ethyl group, propyl group, or butyl group.

[0079] In one aspect of the invention, the dual catalyst system may further comprise an activator. For example, the catalyst system contains an activator-support, an aluminoxane compound, an organoboron compound or an organoborate compound, an ionizing ionic compound, and the like, or any combination thereof. The catalyst system may further comprise one or more than one activator.

[0080] In one aspect of the invention, said polymerization process is operated as gas phase polymerization. In one aspect of the invention, said polymerization process is operated at the temperature in the range from 60 to 100 °C and the total pressure in the range from 15 to 30 bars.

[0081] In one aspect of the invention, said polyethylene composition may further comprise the additives selected from primary antioxidants, secondary antioxidants, processing aids, nucleating agents, acid scavengers, plasticizers, stabilizers, anticorrosion agents, blowing agents, ultraviolet light absorbers, quenchers, antistatic agents, slip agents, pigments, dyes and fillers, cure agents or any combination thereof. These and other general additives in the polyolefin industry may be present in the polyethylene composition from 0.01 to 50 % by weight, preferably 0.1 to 20 % by weight, most preferably 1 to 5 % by weight.

[0082] In particular, the primary antioxidants, secondary antioxidants, processing aids, or mixture thereof may be present in the polyethylene composition from 0.001 to 5 % by weight, preferably from 0.02 to 5 % by weight.

[0083] In one aspect of the invention, said polyethylene composition may be further processed by any suitable methods selected from, but not limited to, calendering, casting, coating, compounding, extrusion, foaming; all forms of molding including compression molding, injection molding, blow molding, rotational molding, and transfer molding; film blowing or casting and all methods to form film, such as uniaxial or biaxial orientation; thermoforming, including by lamination, pultrusion, protrusion, draw reduction, spinbonding, melt spinning, melt blowing, and other forms of fiber and nonwoven fabric formation, and combinations thereof.

[0084] In one aspect of the invention, said polyethylene composition and mixture or blend thereof are useful in forming operations, such as extrusion and co-extrusion of film, sheet, and fiber, including blow molding, injection molding, and rotary molding. Film includes blown film or cast film formed by co-extrusion or by lamination that is useful as shrink film, cling film, stretch film, sealing film, oriented film, snack packaging, heavy duty bag, grocery sack, baked and frozen food packaging, medical packaging, industrial liner, membrane, and others in the food-contact and non- food-contact applications. Fiber includes melt spinning, solution spinning and the operation of melt blown fiber for use in woven or non-woven form to prepare filter, diaper, medical garment, geotextile, and others. The extruded article includes medical tube, wire and cable coating, pipe, geomembrane, and pond liner. The molded article includes single and multi-layered structure in the form of bottle, tank, large hollow article, rigid food container and toy, and others.

[0085] In another embodiment, this invention relates to the article prepared from the polyethylene composition as described above. Preferably, said article is film.

[0086] In one aspect of the invention, film has tensile modulus in the machine direction of 200 MPa or more, preferably 250 MPa or more. Film has tensile modulus in the transverse direction of 200 MPa or more, preferably 250 MPa or more.

[0087] In one aspect of the invention, film has tensile strength in the machine direction of 25 MPa or more, preferably 30 MPa or more. Film has tensile strength in the transverse direction of 20 MPa or more, preferably 25 MPa or more.

[0088] In one aspect of the invention, film has elongation at break in the machine direction of 700 % or more, preferably 800 % or more, most preferably 900 % or more. Film has elongation at break in the transverse direction of 600 % or more, preferably 700 % or more.

[0089] In one aspect of the invention, film has Elmendorf tear in the machine direction of 400 grams-force (gf) or more, preferably 500 grams-force or more. Film has Elmendorf tear in the transverse direction of 600 grams-force or more, preferably 650 grams-force or more.

[0090] In one aspect of the invention, film has puncture resistance of 60 N or more, preferably 70

[0091] N or more, most preferably 80 N or more. Definition and measuring method

[0092] - Density

[0093] The density in this invention means the density of polyethylene which was measured using water displacement method according to ASTM D792 (Method A) at the temperature of 23 °C.

[0094] - Melt flow rate (MFR or MI)

[0095] The melt flow rate in this invention means the melt flow rate of polyethylene which is used to identify the melt flowability of polymer under testing condition at 190 °C with load of 2.16 kg. Said melt flow rate was measured with a melt flow indexer (MI-4, GOTTFERT) according to ASTM D1238.

[0096] - Co-monomer content

[0097] The co-monomer content in this invention is the co-monomer content analyzed by high resolution13C nuclear magnetic resonance (13C-NMR) spectroscopy.13C-NMR spectra were recorded by Bruker 500 Hz NMR spectrometer (A VANCE III HD) with Broad Band Observation probe. The sample was prepared by subjecting polymer sample to dissolve with deuterated 1, 1,2,2- tetrachroloethane-d2 as solvent in order to dissolve the sample at the temperature of 130 °C.

[0098] - Gel Permeation Chromatography (GPC)

[0099] The gel permeation chromatography was operated by preparing about 1 mg / mL of polymer solution with dissolving the sample in 1,2,4-trichlorobenzene (TCB) containing 300 ppm of butylated hydroxytoluene (BHT) at the temperature of 160 °C for 60 min. Then 200 mg of sample solution was injected into the high temperature gel permeation chromatography equipped with 3 detectors (3D-GPC, Polymer Char, S.A., Valencia, Spain), which are an infrared detector (IR5), a viscometer, and a multi-angle light scattering detector (Wyatt technology), and using a 3 PLgel Olexis column (Agilent) with a flow rate of 1 mL / min at the column temperature of 160 °C and the detector temperature of 160 °C. The data was processed by GPC One® Software (Polymer Char).

[0100] - Molecular weight and Molecular weight distribution (MWD)

[0101] The number-average molecular weight (Mn), weight-average molecular weight (Mw), and Z average molecular weight (Mz) were analyzed by gel permeation chromatography (GPC) as described in the part of gel permeation chromatography (GPC).

[0102] The molecular weight distribution (MWD) according to this invention means the molecular weight distribution calculated by dividing the weight-average molecular weight (Mw) by the number-average molecular weight (Mn).

[0103] - Deconvolution method of chromatogram of gel permeation chromatography

[0104] The chromatogram obtained from gel permeation chromatography was subjected to deconvolute using Schulz-Flory distribution in the molecular weight distribution deconvolution. Said method might identify the catalyst behavior during polymerization. However, it might not identify the actual number of active sites of the catalyst.

[0105] Said deconvolution method has been described in the research document of Abdulaziz A. Alghyamah et., al. (Macromolecular Rapid Communications, 2009, 30(4-5), 384-393) for determination of the correlated percentage by weight (wt%) for each component of polyethylene using weight proportion of each component of polyethylene, and the correlated weight-average molecular weight (Mw) and number-average molecular weight (Mn) using mathematical calculation of the molecular weight distribution in the form of Schulz-Flory distribution. Said method fixes the polydispersity index (PDI) which indicates the width of the molecular weight distribution in theory of 2 for single-site catalyst and fixes the average molar mass of repeating unit (MaVg) of polyethylene of 28. - Short chain branches (SCB) and Short chain branching distribution (SCBD)

[0106] The determination of the number of short chain branches per 1 ,000 total carbon atoms is shown in the form of bulk SCB / 1000TC across the molecular weight distribution. In said determination, the number of short chain branches was corrected by deducting the methyl group at chain end under the assumption that each chain is linear and terminated by a methyl group at each chain end. The number of short chain branches was analyzed by gel permeation chromatography (GPC) equipped with the infrared detector (IR5, Polymer Char, S.A., Valencia, Spain). The analysis method of the number of short chain branches has been disclosed in the research document of A. Ortin et., al. (Macromolecular Symposia, 2013, 330, 63-80).

[0107] - gpcBR index

[0108] The gpcBR index in this invention means the gpcBR index being used to identify the branching level of polymer with a high precision. The gpcBR index of linear polymer would be close to zero, while the branched polymer would have the gpcBR index greater than zero. In fact, the gpcBR index shows the fractional change of intrinsic viscosity ([r|]) because of molecular size contraction effect as the result of polymer branching. The gpcBR index is the measurement of branching level of polymer by combining the measurements of intrinsic viscosity and absolute MW from viscometer and light scattering (LS) detector. The analysis of the gpcBR index has been disclosed in patent document EP3176213A1. The gpcBR index could be calculated from the following equation: where Mw.cc, Mv.cc, and [r|]cc are the weight-average molecular weight, viscosity average molecular weight, and intrinsic viscosity, respectively, from the calculation by conventional gel permeation chromatography (GPC) on the assumption that the polymer is linear with no long chain branch (LCB), [r|] is the actual intrinsic viscosity that is the value measured from the online viscometer calculated by viscometer peak area method, Mw is the weight average of absolute molecular weight obtained from light scattering (LS) detector and calculated by LS peak area method. The Mark-Hou wink-Sakurada coefficients for a and K are 0.725 and 0.0004416, respectively, for polyethylene in 1,2,4-trichlorobenzene (TCB) at the temperature of 160 °C.

[0109] - Cross-fractionation chromatography (CFC)

[0110] The cross-fractionation chromatography was operated by cross-fractionation chromatography instrument (S.A., Valencia, Spain). Said technique was the use of gel permeation chromatography (GPC) technique combined with temperature rising elution fractionation (TREF) technique. The analysis method has been disclosed in the research document of Alberto Ortin et., al. (Macromolecular Symposia, 2007, 257, 13-28).

[0111] Said analysis could be performed by preparing the polymer solution having concentration about 4 mg / mL with dissolving the sample in 1,2,4-trichlorobenzene (TCB) containing 300 ppm of butylated hydroxytoluene (BHT) at the temperature of 160 °C for 60 min. The 0.5 mL of solution containing 2 mg of polymer was loaded into the center of the TREF column. The temperature of TREF column was reduced and maintained at about 100 °C for 45 min. Then, the temperature of TREF column was slowly cooled with the reduction rate of the temperature of 0.2 °C / min until the temperature reached 30 °C. Then, the temperature was kept at 30 °C for 30 min before injecting the soluble fraction into high temperature gel permeation chromatography column equipped with an infrared detector (IR5, Polymer Char, S.A., Valencia, Spain) and using a 3 PLgel Olexis column (Agilent) with a flow rate of 1 mL / min at the column temperature of 160 °C and the detector temperature of 160 °C. Then, the temperature of TREF column was increased to the fraction set-points in a stepwise manner to analyze the molecular weight of each fraction having temperature raising to 120 °C. The data was processed by GPC One® Software (Polymer Char).

[0112] The weight- average elution temperature and weight-average molecular weight of the aggregates of fractions divided into 3 temperature ranges, as shown in table 4, which are temperature less than 60 °C, temperature from 60 to 90 °C, and temperature more than 90 °C, were calculated according to the conventional definition of weight-average, wherein the fraction with less than 0.5 % by weight was not included for the calculation.

[0113] The calculation of the weight-average elution temperature (Tw) of polymer of the individual fractions or of aggregates of fractions could be done using the following equation: where Ti is the elution temperature of each eluted fraction and Wi is the normalized % by weight of each eluted fraction.

[0114] The calculation of the weight-average molecular weight (Mw) of polymer of the individual fractions or of aggregates of fractions could be done using the following equation: where MWiis the weight-average molecular weight of each eluted fraction and Wi is the normalized % by weight of each eluted fraction.

[0115] - Twl, Tw2, Mwl, and Mw2

[0116] The Twl, Tw2, Mwl, and Mw2 were calculated from the analysis result of the crossfractionation chromatography. The calculation method of Twl, Tw2, Mwl, and Mw2 has been disclosed in the patent document W02019108314A1. The Mwl / Mw2 is the ratio of weight- average molecular weight (Mw) for a first half of the temperature rising elution fractionation (TREF) curve from the cross-fractionation chromatography (CFC) analysis to the weight-average molecular weight for a second half of the temperature rising elution fractionation curve.

[0117] The Twl-Tw2 is the difference between the weight-average elution temperature (Tw) for a first half of the temperature rising elution fractionation curve and the weight-average elution temperature for a second half of the temperature rising elution fractionation curve.

[0118] - Composition distribution breadth index (CDBI)

[0119] The composition distribution breadth index was analyzed using temperature rising elution fractionation (TREF) instrument in which the analysis method of CDBI value is known by a person skilled in the art, for example, as disclosed in patent document W01993003093A1.

[0120] - T75, T50, and T25

[0121] T75, T50, and T25 are temperatures at which 75 %, 50 %, and 25 %, respectively, of the polymer is eluted, that are analyzed using temperature rising elution fractionation (TREF) technique. T75-T25 represents a homogeneity of the composition distribution analyzed using the above technique. Said analysis and calculation methods have been disclosed in patent document W02009109367A1.

[0122] - Polymer melt strength

[0123] The polymer melt strength at the temperature of 190 °C was determined using capillary rheometer (Rosand RH7, NETZSCH) in which the molten polymer was extruded through a capillary die having a die dimension of 2 mm x 20 mm x 180 degree at a constant speed of 10 mm / min. - Shear viscosity

[0124] The shear viscosity was measured as a function of shear rate at the temperature of 190 °C using capillary rheometer (Rosand RH7, NETZSCH) in which the molten polymer was extruded through a capillary die having a die dimension of 1 mm x 16 mm x 180 degree.

[0125] - Monolayer film preparation

[0126] The preparation of the monolayer film or single layer film having a thickness of 50 pm was performed using film blowing machine (COLLIN) with a ratio between bubble diameter and die diameter or a blow-up ratio of 2.5: 1 and an output of 1.62 kg / hr.

[0127] - Tensile modulus

[0128] The tensile modulus of the blown film in machine direction (MD) and in transverse direction (TD) were tested according to ASTM D882-12 using universal testing machine (UTM).

[0129] - Tensile strength at break

[0130] The tensile strength at break of the blown film in machine direction (MD) and in transverse direction (TD) were tested according to ASTM D882-12 using universal testing machine (UTM) at a crosshead speed of 500 mm / min with a gauge length of 50 mm at 23 ± 2 °C and a relative humidity percentage of 50 ± 5 %.

[0131] - Elongation at break

[0132] The elongation at break of the blown film in machine direction (MD) and in transverse direction (TD) were tested according to ASTM D882-12 using universal testing machine (UTM).

[0133] - Elmendorf tear

[0134] The Elmendorf tear of the blown film in machine direction (MD) and in transverse direction (TD) were tested according to ASTM D1922 (83-76-10, TMI).

[0135] - Puncture resistance The puncture resistance of the blown film was tested according to ASTM D5748 using universal testing machine (UTM) with a speed of 250 mm / min at the temperature of 23 ± 2 °C and a relative humidity percentage of 50 ± 5 %.

[0136] The following examples are only for demonstrating one aspect of this invention, not for limiting the scope of this invention in any way.

[0137] Sample according to the invention 1

[0138] The sample according to the invention 1 was the polyethylene composition comprising the polyethylene prepared by gas phase polymerization process using single reactor with the dual catalyst system comprising the unbridged Group IV transition metal based metallocene compound as shown in structure 1 and the bridged Group IV transition metal based metallocene compound as shown in structure 2, wherein said both metallocene compounds were supported on the cosupport which was silica. The polymerization conditions were operated at a temperature of 60 to 100 °C, a total pressure in the range of 18 to 27 bars, a weight ratio between 1-hexene to ethylene (C6 / C2) of about 0.1 (g / g), a weight ratio between hydrogen to ethylene (H2 / C2) of about 0.000006 (g / g), and a reaction time of 60 to 120 min.

[0139] Sample according to the invention 2

[0140] The sample according to the invention 2 was the polyethylene composition comprising the polyethylene prepared by the same gas phase polymerization process using single reactor with the dual catalyst system and the polymerization conditions as sample according to the invention 1, except for a weight ratio between 1-hexene to ethylene (C6 / C2) of about 0.1 (g / g) and a weight ratio between hydrogen to ethylene (H2 / C2) of about 0.000008 (g / g).

[0141] Sample according to the invention 3 The sample according to the invention 3 was the polyethylene composition comprising the polyethylene prepared by the same gas phase polymerization process using single reactor with the dual catalyst system and the polymerization conditions as sample according to the invention 1, except for a weight ratio between 1 -hexene to ethylene (C6 / C2) of about 0.08 (g / g) and a weight ratio between hydrogen to ethylene (H2 / C2) of about 0.00002 (g / g).

[0142] Comparative sample 1

[0143] The comparative sample 1 was the polyethylene composition comprising the polyethylene prepared by gas phase polymerization process using single reactor with the unbridged Group IV transition metal based metallocene compound as shown in structure 1 which is supported on silica support. The polymerization conditions were operated using the same polymerization conditions as sample according to the invention 1.

[0144] Comparative sample 2

[0145] The comparative sample 2 was the polyethylene composition comprising the polyethylene prepared by gas phase polymerization process using single reactor with the bridged Group IV transition metal based metallocene compound as shown in structure 2 which is supported on silica support. The polymerization conditions were operated using the same polymerization conditions as sample according to the invention 1.

[0146] Comparative samples 3 to 6

[0147] The comparative samples 3 to 6 were the commercial polyethylene compositions which are known in the art of film production and are commercially available. Said polyethylene was prepared by gas phase polymerization process technology using 1 -hexene as co-monomer. These samples could be used for polymer comparison in terms of characteristic, property, and application with this invention. Table 1 : Polymer properties of the samples according to the invention and comparative samples

[0148]

[0149] Table 2: Number of short chain branches to 1,000 total carbon atoms and ratio of short chain branches at each molecular weight range of the samples according to the invention and comparative samples, wherein the number of short chain branches to 1,000 total carbon atoms was determined at logMl, logM2, and logM3, where logMl, logM2, and logM3 were logarithm of molecular weight in gel permeation chromatography analysis equipped with an infrared detector (GPC-IR) at 4, 5, and 5.5, respectively.

[0150] Table 3: Deconvolution results of chromatogram of gel permeation chromatography using Schulz-Flory distribution of the samples according to the invention

[0151] Table 4: Deconvolution results of chromatogram of gel permeation chromatography using Schulz-Flory distribution of comparative

[0152] 5 samples

[0153] Table 5: Cross-fractionation chromatography (CFC) analysis of the sample according to the invention and comparative samples

[0154] Table 6: Properties of blown film prepared from polymer of the sample according to the invention and comparative samples

[0155] As shown in Table 1, the samples according to the invention have higher gpcBR index than the comparative samples, demonstrating higher branching level. Considering Twl-Tw2 value, it is found that there is the broad chemical composition distribution (CCD). When considering the chromatogram of gel permeation chromatography and short chain branching distribution in figures 1 to 3 and tables 2 to 4, it is found that the samples according to the invention have high molecular weight component having higher comonomer incorporation and high proportion of short chain branches in high molecular weight component. Comparing with the comparative samples 1 and 2 prepared by the catalyst system comprising the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound, respectively, including the comparative samples 3 and 4, it is found that the samples according to the invention clearly demonstrate the high molecular weight component having higher comonomer incorporation than the comparative samples 1 to 4. When comparing with the comparative samples 5 and 6, it is found that the characteristics of short chain branching distribution are different. The samples according to the invention show a unique short chain branching distribution in which the low molecular weight component has higher comonomer incorporation and the number of short chain branches in the range of logarithm of molecular weight in the analysis by gel permeation chromatography equipped with an infrared detector (GPC-IR) at 5 tends to decrease, while the comparative samples 5 and 6 show the low molecular weight component having low comonomer incorporation. From the cross-fractionation chromatography (CFC) analysis as shown in figures 4 to 6 and table 5, the differences of characteristics of the polymer composition eluted in each temperature range are shown.

[0156] As shown in table 1 and figures 3 and 7, the samples according to the invention have significantly improved polymer melt strength and also show better shear sensitivity behavior when comparing to the comparative samples. This indicates improved processibility of polyethylene.

[0157] From table 6 that shows the properties of article which is film prepared from the sample according to the invention and the comparative samples, it is found that film prepared from the sample according to the invention shows significantly higher puncture resistance and elongation at break in machine direction than the comparative samples. This also includes higher tensile modulus in machine direction than the comparative samples. That is, the samples according to the invention also show improved mechanical properties. This indicates that the samples according to the invention have excellent balance between processibility and mechanical property. These are the results of the polymer which is characterized in the molecular weight distribution and short chain branching distribution, as shown in this present invention, due to synergistic behavior of the dual catalyst system that can be used to prepare such polymer using only single polymerization reactor.

[0158] Best Mode or Preferred Embodiment of the Invention

[0159] Best mode or preferred embodiment of the invention is as provided in the description of the invention.

Claims

Claims1. A polyethylene composition comprising polyethylene comprising ethylene monomer and C3-C20 a-olefin comonomer in an amount from 0.1 to 35 % by weight, wherein said polyethylene has the following properties:- a density in a range from 0.910 to 0.935 g / cm3;- a melt flow rate (MFR) in a range from 0.1 to 100 g / 10 min (as measured according to ASTM D 1238 at a temperature of 190 °C and load of 2.16 kg);- a molecular weight distribution (Mw / Mn) from 3 to 50;- a gpcBR index of equal to or greater than 0.3;- a multimodality characteristic showing in the chromatogram of gel permeation chromatography (GPC) wherein said chromatogram is subjected to the deconvolution using Schulz-Flory distribution and comprises: a) 30 to 55 %, comparing to total area of the chromatogram, for the first component having a weight-average molecular weight (Mw) from 20,000 to 75,000 g / mol; b) 35 to 55 %, comparing to total area of the chromatogram, for the second component having a weight-average molecular weight from 80,000 to 200,000 g / mol; and c) 5 to 20 %, comparing to total area of the chromatogram, for the third component having a weight-average molecular weight from 300,000 to 800,000 g / mol; and- SCBiogM2 / SCBiogMi of equal to or less than 1, SCBiogMi of greater than 10, and SCBiogM3 / SCBiogM2 of greater than or equal to 1, wherein SCBiogMi is the number of short chain branches (SCB) per 1,000 total carbon atoms of the polyethylene measured at logMl, SCBiogM2 is the number of short chain branches per 1 ,000 total carbon atoms of the polyethylene measured at logM2, and SCBiogM3 is the number of short chain branches per 1,000 total carbon atoms of thepolyethylene measured at logM3, and wherein logMl, logM2, and logM3 is the logarithm of the molecular weight in the gel permeation chromatography analysis equipped with an infrared detector (GPC-IR) at 4, 5, and 5.5, respectively.

2. The polyethylene composition according to claim 1 , wherein said polyethylene has the melt flow rate in the range from 0.1 to 50 g / 10 min.

3. The polyethylene composition according to claim 1, wherein said polyethylene has the molecular weight distribution from 3 to 30.

4. The polyethylene composition according to claim 1 , wherein said polyethylene has the gpcBR index of equal to or greater than 0.3 but less than 1.

5. The polyethylene composition according to claim 4, wherein said polyethylene has the gpcBR index of equal to or greater than 0.3 but less than or equal to 0.7.

6. The polyethylene composition according to claim 1, wherein said polyethylene hasSCBiogM2 / SCB logMi of greater than or equal to 0.7 but less than or equal to 1.

7. The polyethylene composition according to claim 6, wherein said polyethylene hasSCBiogM2 / SCB logMi of greater than or equal to 0.7 but less than 1.

8. The polyethylene composition according to claim 1, wherein said polyethylene hasSCBiogMi of greater than 10 but less than 30.

9. The polyethylene composition according to claim 1, wherein said polyethylene hasSCBiogM3 / SCBiogM2 of greater than 1.

10. The polyethylene composition according to claim 9, wherein said polyethylene hasSCBiogM3 / SCBiogM2 of greater than 1 but less than or equal to 1.3.

11. The polyethylene composition according to claim 1 , wherein said polyethylene hasMwl / Mw2 of less than 1, wherein Mwl / Mw2 is the ratio of the weight-average molecular weight(Mw) for the first half of the temperature rising elution fractionation (TREF) curve from the crossfractionation chromatography (CFC) analysis to the weight-average molecular weight for the second half of the temperature rising elution fractionation curve.

12. The polyethylene composition according to claim 1, wherein said polyethylene has Twl-Tw2 of from -16 to -38, wherein Twl-Tw2 is the difference between the weight-average elution temperature (Tw) for the first half of the temperature rising elution fractionation curve and the weight- average elution temperature for the second half of the temperature rising elution fractionation curve.

13. The polyethylene composition according to claim 1, wherein said polyethylene has the multimodality characteristic showing in the elution profile from the cross-fractionation chromatography (CFC) analysis, comprising: a) 10 to 30 % by weight of the fraction eluted in the temperature range of lower than 60 °C has the weight-average molecular weight from 40,000 to 120,000 g / mol; b) 50 to 80 % by weight of the fraction eluted in the temperature range of from 60 to 90 °C has the weight-average molecular weight from 100,000 to 200,000 g / mol; and c) 5 to 25 % by weight of the fraction eluted in the temperature range of higher than 90 °C has the weight-average molecular weight from 100,000 to 200,000 g / mol.

14. The polyethylene composition according to claim 1, wherein said polyethylene has T75- T25 of from 20 to 30, wherein T75 and T25 are temperatures at which 75 % and 25 %, respectively, of the polymer is eluted from the temperature rising elution fractionation (TREF) analysis.

15. The polyethylene composition according to claim 1, wherein said polyethylene has the composition distribution breadth index (CDBI) in the range from 35 to 55 %.

16. The polyethylene composition according to claim 1, wherein said polyethylene has theZ average molecular weight (Mz) analyzed by the gel permeation chromatography (GPC) of from 300,000 to 600,000 g / mol.

17. The polyethylene composition according to claim 1, wherein said polyethylene has the Z average molecular weight to the number-average molecular weight (Mz / Mn) in the range from 5 to 40.

18. The polyethylene composition according to claim 1, wherein said polyethylene has the Z average molecular weight to the weight- average molecular weight (Mz / Mw) in the range from 2 to 10.

19. The polyethylene composition according to claim 1, wherein said polyethylene has the polymer melt strength of equal to or greater than 10 cN.

20. The polyethylene composition according to claim 1, wherein the C3-C20 a-olefin comonomer is selected from 1 -hexene, 1 -octene, 1 -decene, or mixture of said a-olefin comonomers.

21. The polyethylene composition according to claim 20, wherein the C3-C20 a-olefin comonomer is 1 -hexene.

22. The polyethylene composition according to claim 1, wherein said polyethylene is prepared by polymerization process using single reactor with a dual catalyst system comprising the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound.

23. The polyethylene composition according to claim 22, wherein said dual catalyst system comprising the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound is supported on a co-support.

24. The polyethylene composition according to claim 23, wherein said co-support is selected from magnesium chloride, silica, alumina, magnesia, titania, zirconia, montmorillonite, zeolite, silica-chromium, silica-alumina, silica-titania, silica-magnesia, or mixture thereof.

25. The polyethylene composition according to claim 22, wherein the Group IV transition metal is selected from hafnium, titanium, or zirconium.

26. The polyethylene composition according to claim 22, wherein the weight proportion of the bridged Group IV transition metal based metallocene compound is in the range from 20 to 80 % comparing to the total weight of the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound.

27. The polyethylene composition according to claim 26, wherein the weight proportion of the bridged Group IV transition metal based metallocene compound is in the range from 40 to 80 % comparing to the total weight of the unbridged Group IV transition metal based metallocene compound and the bridged Group IV transition metal based metallocene compound.

28. The polyethylene composition according to claim 22, wherein said unbridged Group IV transition metal based metallocene compound is the unbridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand.

29. The polyethylene composition according to claim 28, wherein said cyclopentadienyl ligand has substituent that is independently selected from hydrogen or alkyl group.

30. The polyethylene composition according to claim 22, wherein said bridged Group IV transition metal based metallocene compound is selected from the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand, or the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and nitrogen.

31. The polyethylene composition according to claim 30, wherein said bridged Group IV transition metal based metallocene compound is selected from the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand.

32. The polyethylene composition according to claim 31 , wherein said bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand is the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand, wherein said cyclopentadienyl ligand has substituent that is independently selected from hydrogen or alkyl group; and cyclopentadienyl ligand, wherein said cyclopentadienyl ligand has substituents in which any two adjacent groups of said substituents are joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, optionally wherein said aromatic ring is substituted by one or more groups.

33. The polyethylene composition according to claim 31 or 32, wherein said bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand and cyclopentadienyl ligand is the bridged Group IV transition metal based metallocene compound between cyclopentadienyl ligand, wherein said cyclopentadienyl ligand has substituent that is independently selected from hydrogen or alkyl group; and cyclopentadienyl ligand, wherein said cyclopentadienyl ligand has substituents in which any two adjacent groups of said substituents are joined in such a way that when linking with the atom to which they are bound, the aromatic ring having 6 carbon atoms would be formed, wherein said aromatic ring is substituted by one or more groups selected from hydrogen, alkyl group, cycloalkyl group, aryl group, or arylalkyl group, whereas remaining substituent that are not joined together is independently selected from hydrogen or alkyl group.

34. The polyethylene composition according to any one of claim 30 to 33, wherein said bridged Group IV transition metal based metallocene compound has the bridging position selected from carbon or silicon, and the bridging position has substituent selected from hydrogen or alkyl group.

35. The polyethylene composition according to claim 22, wherein said polymerization process is operated as gas phase polymerization.

36. An article prepared from the polyethylene composition according to any one of the preceding claims is film.

37. The article according to claim 36, wherein film has tensile modulus in machine direction of 200 MPa or more.

38. The article according to claim 36, wherein film has elongation at break in machine direction of 700 % or more.

39. The article according to claim 36, wherein film has puncture resistance of 60 N or more.

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