Polyethylene composition suitable for hinge component

Abstract

The invention relates to a polyethylene composition, comprising an ethylene polymer comprising or consisting of: a) a low molecular weight component (A); and b) a high molecular weight component (B); wherein the polyethylene composition has: • a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1 :2011 at 190 °C and measured at 21.6 kg; and • a density of ≥ 956.0 and ≤ 965.0 kg / m3, preferably ≥ 957.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and • a complex viscosity (η 100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 °C; The invention further relates to an article comprising the polyethylene composition and the use of the polyethylene composition for manufacturing an hinge component.

Description

23POLY0140-WO-ORD 1 POLYETHYLENE SUITABLE FOR HINGE COMPONENT FIELD OF INVENTION

[0001] The invention relates to a polyethylene composition and to articles, for example a hinge component, that are prepared from such a polyethylene composition. BACKGROUND

[0001] In various consumer products such as bottles and containers, hinges used in caps and closures play an important role in packaging. A living hinge is one such form of a hinge, which is a thin, flexible hinge connecting two relatively rigid parts. Living hinges are usually made from the same material as the rigid parts and is typically used to join rigid parts of a container, allowing them to bend along the line of the hinge.

[0002] A commonly used material for making a hinge is polypropylene. Polypropylene as a material has suitable fatigue performance, good environmental stress crack resistance (ESCR) performance, low cost of manufacturing and excellent processability. However, since bottles or tubes for cosmetic / personal care applications are often made of polyethylene, the difference in material properties between polyethylene and polypropylene polymers, may adversely affect the mechanical performance of the polyethylene recyclates.

[0003] Therefore, from a sustainability point of view, there is often a need to have a mono- material packaging where the bottle and tube is of the same material as that of the hinge or the cap for better recyclability. In addition, an aspect to consider is polymer pollution that is to be addressed when designing a hinge component. Bottle caps are preferred to be hinged to the base and the hinge to be resistant enough in order for the lid not to detached during the bottle use and end up polluting the environment.

[0004] In addition, for any viable commercial use of a hinge, the hinge needs to have desirable fatigue performance, good environmental stress crack resistance (ESCR) while having the desired processability. Accordingly, it is an objective of the present invention to provide a polyethylene composition, which can be used for preparing hinges that has a balance of fatigue performance and environmental stress crack resistance (ESCR) while maintaining a desired processability.23POLY0140-WO-ORD 2 DESCRIPTION

[0005] Accordingly, the one or more objectives of the present invention is achieved by a polyethylene composition, comprising an ethylene polymer comprising or consisting of: a) ≥ 60.0 and ≤ 75.0 wt.%, preferably ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000, preferably wherein the weight average molecular weight (Mw) is determined in accordance with ASTM D6474-12; and b) ≥ 25.0 and ≤ 40.0 wt.%, preferably ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; preferably wherein the low molecular weight component (A) is an ethylene homopolymer or an ethylene copolymer and preferably wherein the high molecular weight component (B) is a copolymer of ethylene and a C3-C20 comonomer, preferably the high molecular weight component (B) is a copolymer of ethylene and a C3-C8 alpha olefin; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and ^ a density of ≥ 954.0 and ≤ 965.0 kg / m3, preferably ≥ 954.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC.

[0002] The high molecular weight component (B) may be measured using any known techniques using ISO and ASTM standards such as deconvolution technique based on ASTM D6474-12.23POLY0140-WO-ORD 3

[0003] Preferably, the polyethylene comprising the ethylene polymer comprises or consists of: a) ≥ 60.0 and ≤ 75.0 wt.%, preferably ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and b) ≥ 25.0 and ≤ 40.0 wt.%, preferably ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 21.6 kg; and ^ a density of ≥ 954.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC.

[0004] Advantageously, the polyethylene composition of the present invention has an excellent balance of processability, environmental stress cracking resistance (ESCR), melt strength, and stiffness.

[0005] In an aspect of the invention, the invention relates to the use of the polyethylene composition of the present invention for improving the properties of stiffness, processability during injection molding, hardness and environmental stress cracking resistance (ESCR), of an article. Preferably wherein the article is a hinge component.

[0006] Preferably, the polyethylene composition has at least one of: (a) a Bell Test resistance F50 of > 50 hours and < 300 hours when determined in accordance with ASTM D1693 Method B at 50 ºC in 10% IGEPAL; and / or23POLY0140-WO-ORD 4 (b) a Yield stress of ≥ 26.0 MPa and ≤ 35.0 preferably ≥ 26.0 MPa and ≤ 32.0 MPa, preferably ≥ 26.5 MPa and ≤ 31.0 MPa as measured according to ISO 527-2 at 23 ºC; and / or (c) a tensile modulus value of ≥ 1350 MPa and ≤ 1550 MPa, preferably ≥ 1380 MPa and ≤ 1450 MPa as measured according to ISO 527-2 at 23 ºC.

[0007] Preferably, the polyethylene composition has: (a) a Bell Test resistance F50 of > 50 hours and < 300 hours when determined in accordance with ASTM D1693 Method B at 50 ºC in 10% IGEPAL; and (b) a Yield stress of ≥ 26.0 MPa and ≤ 35.0 MPa, preferably ≥ 26.0 MPa and ≤ 32.0 MPa, preferably ≥ 26.5 MPa and ≤ 31.0 MPa as measured according to ISO 527-2 at 23 ºC; and (c) a tensile modulus value of ≥ 1350 MPa and ≤ 1550 MPa, preferably ≥ 1380 MPa and ≤ 1450 MPa as measured according to ISO 527-2 at 23 ºC.

[0008] The polyethylene composition of the present invention demonstrates a desired shear thinning behavior when subjected to high stress. The polyethylene composition according to the invention has a relatively low viscosity at a relatively high shear rate, which results in a good processability for injection molding.

[0009] Preferably, the polyethylene composition comprises a melt flow ratio (MF 21.6 / 5.0) of ≥ 10.0 and ≤ 30.0, preferably ≥ 12.0 and ≤ 22.0, preferably ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and 5.0 kg respectively.

[0010] For example, the polyethylene composition has a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 45.0 Pa.s and ≤ 65.0 Pa.s, preferably ≥ 48.0 Pa.s and ≤ 60.0 Pa.s, preferably ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC.23POLY0140-WO-ORD 5

[0011] Preferably, the polyethylene has a Strain Hardening modulus of ≥ 8.0 MPa and ≤ 25.0 MPa, preferably ≥ 12.0 MPa and ≤ 22.0 MPa, preferably ≥ 12.0 MPa and ≤ 20.0 MPa, as measured in accordance with ISO 18488.

[0012] The term ethylene polymer as used in this disclosure means a polymer, the majority by weight, of which is derived from ethylene monomer units. The ethylene polymer may be an ethylene homopolymer or a copolymer of ethylene and a C3-C20comonomer.

[0013] Preferably, the polyethylene composition has a total content of polymeric units derived from C3-C8alpha olefin of ≥ 0.35 and ≤ 0.85 mol.%, preferably ≥ 0.35 and ≤ 0.70 mol.%, with regard to the total moles of the polyethylene composition.

[0014] Preferably, the polyethylene composition has a total content of polymeric units derived from ethylene of ≥ 99.15 and ≤ 99.65 mol.%, preferably ≥ 99.30 and ≤ 99.65 mol.%, with regard to the total moles of the polyethylene composition.

[0015] Preferably, the polyethylene composition has a total content of polymeric units derived from C3-C8 alpha olefin of ≥ 0.35 and ≤ 0.85 mol.%, preferably ≥ 0.35 and ≤ 0.75 mol.%, with regard to the total moles of the polyethylene composition, preferably wherein the mole content of the polymeric units in the polyethylene composition is determined using InfraRed spectroscopy.

[0016] Preferably, the C3-C8 alpha olefin comonomer is 1-hexene, and preferably wherein the total content of polymeric units derived from 1-hexene comonomer is from ≥ 0.35 and ≤ 0.50 mol.%, with regard to the total moles of the polyethylene composition. Preferably, the polyethylene composition has a total content of polymeric units derived from ethylene of ≥ 99.5 and ≤ 99.65 mol.%, with regard to the total moles of the polyethylene composition.

[0017] The comonomer content influences the degree of low chain branching which in turn influences the degree of processability. Preferably, the polyethylene composition has a Long Chain23POLY0140-WO-ORD 6 Branch Index of ≥ 0.3 and ≤ 1.2, preferably ≥ and ≤ 1.0, wherein LCB index is determined by ^^^^^^ ൌఎబ.బభூ^ௗ^௫ ^య.లమవల∙^^^ಾ^^ష^.యరయవ, where η0.01 is the viscosity of the polyethylene composition at 190 ºC and at 0.01 rad / s expressed in Pa*s, and Mw is the weight average molecular weight of the polyethylene composition as expressed in kg / mol.

[0018] Preferably, the polyethylene composition has a weight average molecular weight (Mw) of ≥ 100 kg / mol and ≤ 200 kg / mol, preferably ≥ 100 kg / mol and ≤ 180 kg / mol, preferably ≥ 105 kg / mol and ≤ 130 kg / mol, determined in accordance with ASTM D6474-12.

[0019] Preferably, the polyethylene composition has a Z-average molecular weight (Mz) of ≥ 700 kg / mol and ≤ 1500 kg / mol, preferably ≥ 1000 kg / mol and ≤ 1200 kg / mol determined in accordance with ASTM D6474-12.

[0020] Preferably, the polyethylene composition has a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 25.0, preferably ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12.

[0021] Preferably, the polyethylene composition has a Peak Ratio ranging from ≥ 1.8 and ≤ 10.0, preferably ≥ 1.8 and ≤ 8.0, wherein Peak Ratio is defined as: ^^^^^ / ^^^^^^^^^^^^^^^^^ൈ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^,^^^^^^^^ ^^^^^^^^^^^^^^^^^^ൌ^^^^^ / ^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^,^^^^^^^^ൈ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^wherein: - (dW / dLogMw)at Mwpeak,LMWFis the value of the molecular weight distribution for the low molecular weight component (A) of the ethylene polymer at the maximum value of the molecular weight distribution as measured (Mw peak); - (dW / dLogMw)at Mwpeak,HMWFis the value of the molecular weight distribution for the high molecular weight component (B) of the ethylene polymer at the maximum value of the molecular weight distribution as measured (Mw peak);23POLY0140-WO-ORD 7 - (PolymerSplit)LMWFis the weight of the low molecular weight component (A) of the ethylene polymer with regard to the total weight of the ethylene polymer; - (PolymerSplit)HMWF is the weight fraction of the high molecular weight component (B) of the ethylene polymer with regard to the total weight of the ethylene polymer.

[0022] The PEAK ratio may for example quantify the spread between the low and high molecular weight components of the ethylene polymer and is indicative of the degree of processability of the polyethylene composition.

[0023] The ethylene polymer may be a bimodal or a multi-modal. It is preferred that the ethylene polymer is bimodal comprising the low molecular weight component (A) and the high molecular weight (B). Low molecular weight component (A) of the ethylene polymer

[0024] The low molecular weight component (A) is present in an amount of ≥ 60.0 and ≤ 75.0 wt.%, preferably ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer.

[0025] The low molecular weight component (A) may be an ethylene homopolymer or an ethylene copolymer. Preferably, the low molecular weight component (A) is an ethylene homopolymer.

[0026] Preferably the low molecular weight component (A) is an ethylene homopolymer or an ethylene copolymer having a density of ≥ 962.0 kg / m3and ≤ 978.0 kg / m3, preferably ≥ 964.0 kg / m3and ≤ 972.0 kg / m3, preferably the low molecular weight component is an ethylene homopolymer having a density of ≥ 964.0 kg / m3and ≤ 978.0 kg / m3, preferably ≥ 967.0 kg / m3and ≤ 972.0 kg / m3. The density may be determined in accordance with ISO 1183.

[0027] Preferably, the low molecular weight component (A) has a ratio of Mw / Mn of ≥ 5.0 and ≤ 11.0, preferably ≥ 6.0 and ≤ 10.0.23POLY0140-WO-ORD 8

[0028] Preferably, the low molecular component (A) of the ethylene polymer has a melt flow index (MFI1.2) of ≥ 15.0 and ≤ 70.0 dg / min, preferably ≥ 35.0 and ≤ 60.0 dg / min, preferably ≥ 45.0 and ≤ 55.0 dg / min determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 1.2 kg.

[0029] Preferably, the low molecular weight component (A) of the ethylene polymer has a weight average molecular weight (Mw) of ≥ 10,000 g / mol and ≤ 70,000 g / mol, preferably ≥ 30,000 g / mol and ≤ 65,000 g / mol, preferably ≥ 30,000 g / mol and ≤ 60,000 g / mol. The values of Mw may be determined in accordance with ASTM D6474-12. High molecular weight component (B) of the ethylene polymer

[0030] The high molecular weight component (B) is present in an amount of ≥ 25.0 and ≤ 40.0 wt.%, preferably ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer.

[0031] The weight average molecular weight (Mw) for the high molecular weight component (B) may be measured using any known techniques using ISO and ASTM standards such as deconvolution technique based on ASTM D6474-12.

[0032] Preferably, the high molecular weight component (B) has a ratio of Mw / Mn of ≥ 4.0 and ≤ 8.0. The values of Mw and Mn for high molecular weight component (B) can be determined can for example by using ASTM D6474-12 based on deconvolution technique.

[0033] Preferably, the high molecular weight component (B) has a density of ≥ 920 and ≤ 950 kg / m3, preferably ≥ 920 and ≤ 946 kg / m3. The density may be determined in accordance with ISO 1183.

[0034] Preferably, the high molecular weight component (B) has a melt flow rate as measured according to ISO 1133-1:2011 at 190 ºC and 21.6 kg of ≥ 0.05 and ≤ 2.0 dg / min, preferably ≥ 0.08 and ≤ 1.0 dg / min, preferably ≥ 0.10 and ≤ 0.5 dg / min.

[0035] The high molecular weight component (B) of the ethylene copolymer may be a copolymer of ethylene and a C3-C20 comonomer. The C3-C20 comonomer is preferably selected from the group consisting of C3-C10 preferably C3-C8 alpha-olefins such as propylene, 1-butene, 1-hexene and 1-octene. For example, the high molecular weight component (B) of the ethylene23POLY0140-WO-ORD 9 polymer is a copolymer comprising units derived from ethylene and a C3-C8alpha olefin comonomer.

[0036] The C3-C8alpha olefin may be present in an amount of ≥ 0.35 and ≤ 0.85 mol.%, preferably ≥ 0.35 and ≤ 0.75 mol.%, with regard to the total moles of the polyethylene composition.

[0037] Preferably, the high molecular weight component (B) is a copolymer of ethylene and 1-butene or ethylene and 1-hexene. Most preferably, component (B) is a copolymer of ethylene and 1-hexene.

[0038] Preferably, the high molecular weight component (B) is a copolymer comprising polymeric units derived from of ethylene and a C3-C8comonomer. Preferably the C3-C8comonomer is selected from propylene, 1-butene, 1-hexene and 1-octene. Preferably, the high molecular weight component (B) is a copolymer of ethylene and 1-butene or an ethylene and 1- hexene. Most preferably, the high molecular weight component (B) is a copolymer of ethylene and 1-hexene.

[0039] Preferably the high molecular weight component (B) of the ethylene polymer has a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol, preferably ≥ 100,000 g / mol and ≤ 600,000 g / mol, preferably ≥ 100,000 g / mol and ≤ 400,000 g / mol.

[0040] Preferably wherein the low molecular weight component (A) is an ethylene homopolymer or an ethylene copolymer; and preferably wherein the high molecular weight component (B) is a copolymer of ethylene and a C3-C20 comonomer, preferably a copolymer of ethylene and a C3-C8alpha olefin. Polyethylene composition

[0041] Preferably the polyethylene composition, comprises the ethylene polymer comprising or consisting of: a) ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and23POLY0140-WO-ORD 10 b) ≥ 32.0 and ≤ 38.0 wt.%, with to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and ^ a density of ≥ 954.0 and ≤ 965.0 kg / m3, preferably ≥ 954.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC; and ^ a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 45.0 Pa.s and ≤ 65.0 Pa.s, preferably ≥ 48.0 Pa.s and ≤ 60.0 Pa.s, preferably ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC; and ^ a melt flow ratio (MF 21.6 / 5.0) of ≥ 12.0 and ≤ 22.0, preferably ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and 5.0 kg respectively; and ^ a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 25.0, preferably ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12.

[0006] Preferably polyethylene composition, comprising the ethylene polymer comprising or consisting of: a) ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and23POLY0140-WO-ORD 11 b) ≥ 32.0 and ≤ 38.0 wt.%, with to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and ^ a density of ≥ 956.0 and ≤ 965.0 kg / m3, preferably ≥ 957.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC; and ^ a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12.

[0007] Preferably the polyethylene composition, comprising the ethylene polymer, comprises or consists of: a) ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and b) ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and23POLY0140-WO-ORD 12 ^ a density of ≥ 956.0 and ≤ 965.0 ≥ 957.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC; and ^ a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 45.0 Pa.s and ≤ 65.0 Pa.s, preferably ≥ 48.0 Pa.s and ≤ 60.0 Pa.s, preferably ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC; and ^ a melt flow ratio (MF 21.6 / 5.0) of ≥ 12.0 and ≤ 22.0, preferably ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and 5.0 kg respectively; and ^ a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 25.0, preferably ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12.

[0008] Preferably, the polyethylene composition, comprising the ethylene polymer, comprises or consists of: a) ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and b) ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and23POLY0140-WO-ORD 13 ^ a density of ≥ 956.0 and ≤ 965.0 preferably ≥ 957.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC; and ^ a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 45.0 Pa.s and ≤ 65.0 Pa.s, preferably ≥ 48.0 Pa.s and ≤ 60.0 Pa.s, preferably ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC; and ^ a melt flow ratio of ≥ 12.0 and ≤ 22.0, preferably ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and 5.0 kg respectively; and ^ a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12; and ^ a weight average molecular weight (Mw) of ≥ 100 kg / mol and ≤ 200 kg / mol, preferably ≥ 100 kg / mol and ≤ 180 kg / mol, preferably ≥ 105 kg / mol and ≤ 130 kg / mol, determined in accordance with ASTM D6474-12.

[0042] Preferably the polyethylene composition, comprises the ethylene polymer comprising or consisting of: a) ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and b) ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 21.6 kg; and23POLY0140-WO-ORD 14 ^ a density of preferably ≥ 957.0 and kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC; and ^ a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC; and ^ a melt flow ratio of ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and 5.0 kg respectively; and ^ a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12; and ^ a Z-average molecular weight (Mz) of ≥ 1000 kg / mol and ≤ 1200 kg / mol determined in accordance with ASTM D6474-12; and ^ a total content of polymeric units derived from C3-C8alpha olefin of ≥ 0.35 and ≤ 0.75 mol.%, with regard to the total moles of the polyethylene composition.

[0043] The polyethylene composition may comprise the polyethylene composition comprising the polyethylene composition comprises ≥ 80.0 wt.% and ≤ 100.wt.%, preferably ≥ 90.0 wt.% and ≤ 100.wt.%, preferably ≥ 95.0 wt.% and ≤ 100.wt.%, preferably ≥ 98.0 wt.% and ≤ 100.wt.% of the ethylene polymer with regard to the total weight of the polyethylene composition; and wherein the polyethylene composition comprises ≥ 0.0 wt.% and ≤ 20.0 wt.%, preferably ≥ 0.0 wt.% and ≤ 10.0 wt.%, preferably ≥ 0.0 wt.% and ≤ 5.0 wt.%, preferably ≥ 0.0 wt.% and ≤ 2.0 wt.%, of additives with regard to the total weight of the polyethylene composition, preferably wherein the additives are selected from anti-oxidants, carbon black, fillers, process stabilisers, anti- oxidants, light and / or heat stabilisers, cross-linking agents and combinations thereof.

[0044] Preferably, the additives are selected from the group consisting of anti-oxidants, fillers, process stabilisers, anti-oxidants, light and / or heat stabilisers, and combinations thereof.23POLY0140-WO-ORD 15 Preferably, the polyethylene composition is cross-linking and additives selected from carbon black.

[0045] In an aspect of the invention, it is preferred polyethylene composition comprises ≥ 98.0 wt.% and ≤ 100.wt.% of the ethylene polymer with regard to the total weight of the polyethylene composition; and wherein the polyethylene composition comprises ≥ 0.0 wt.% and ≤ 2.0 wt.% of additives, preferably wherein the additives are selected from anti-oxidants, carbon black, fillers, process stabilisers, anti-oxidants, light and / or heat stabilisers, cross-linking agents and combinations thereof. Preparing the ethylene polymer and the polyethylene composition

[0046] The ethylene polymer according to the invention may be prepared by a process comprising the steps of producing the low molecular weight component and the high molecular weight component as a bimodal ethylene polymer made by polymerizing the low molecular weight component (high molecular weight component) and subsequently polymerizing the high molecular weight component (low molecular weight component) in the presence of the low molecular weight component (high molecular weight component).

[0047] Accordingly, the invention provides a process for the preparation of the ethylene polymer according to the invention, wherein the process comprises a sequential polymerization process comprising at least two reactors connected in series, wherein said process may comprise the steps of: a) preparing the low molecular weight component (high molecular weight component) in a first reactor using the first set of conditions, b) transferring the low molecular weight component (high molecular weight component) and unreacted monomers of the first reactor to a second reactor, c) feeding monomers to the second reactor, d) preparing the high molecular weight component (low molecular weight component) in the second reactor in the presence of the low molecular weight component (high molecular weight component) to obtain the ethylene polymer.23POLY0140-WO-ORD 16

[0048] Each of the ethylene polymer A and B and the optional further ethylene polymer component(s) may be produced in the presence of known catalyst systems such as a Ziegler Natta catalyst system or a metallocene catalyst system, preferably a Ziegler Natta catalyst system. The polymerization can be carried out in the presence of an anti-static agent or anti fouling agent in an amount ranging between for example 1 and 500 ppm related to the total amount of reactor contents.

[0049] The multi-step slurry polymerization process may be carried out using cascaded reactors and in the presence of a Ziegler Natta catalyst system.

[0050] Alternatively, the ethylene polymer according to the invention may be prepared by a process comprising melt-mixing or solution blending the low molecular weight component and the high molecular weight component made in different reactors to obtain the ethylene polymer. The melt-mixing or solution blending may be carried out in any conventional blending apparatus. The low molecular weight component and the high molecular weight component to be melt-mixed or solution blended may be produced by any known process.

[0051] The ethylene polymer once obtained may be compounded with additives such as carbon black, anti-oxidant, masterbatch, color pigments to obtain the polyethylene composition. The amount of additives may not exceed 10.0 wt.% with regard to the total weight of the polyethylene composition, preferably the amount of additive is not greater than 2.0 wt.% with regard to the total weight of the polyethylene composition.

[0052] In an aspect of the invention, the invention relates to an article comprising the polyethylene composition of the present invention. Preferably the article is a hinge component.

[0053] Preferably, the article comprises > 95.0 wt.%, preferably > 98 wt.%, preferably 100 wt.% with regard to the total weight of the article, of the polyethylene composition.

[0054] A hinged component is a component comprising of at least two bodies which are connected to one another through a flexible hinge. The flexible hinge may be a continuous, partial or segmented section, which is typically thinner than the two or more bodies, so as to act as a23POLY0140-WO-ORD 17 fulcrum or pivot point about which the two or bodies may bend. For example the two or more bodies may bend about the flexible hinge from a molded position into a flexed position.

[0055] The hinged component may be a living hinge. A living hinge or integral hinge is a thin flexible hinge (flexure bearing) made from the same material as the two rigid pieces it connects. It is typically thinned or cut to allow the rigid pieces to bend along the line of the hinge.

[0056] The invention will now be demonstrated with the following non-limiting examples. EXAMPLES

[0057] Purpose: To evaluate the properties of sample specimen prepared from the polyethylene composition of the present invention.

[0058] Catalyst preparation:

[0059] Catalyst 1 - Preparation of a hydrocarbon solution comprising an organic oxygen containing magnesium compound and an organic oxygen containing titanium compound. 100 grams of granular Mg(OC2H5)2and 150 millilitres of Ti(OC4H9)4were brought in a 2 litre round bottomed flask equipped with a reflux condensor and stirrer. While gently stirring, the mixture was heated to 180°C and subsequently stirred for 1.5 hours. During this, a clear liquid was obtained. The mixture was cooled down to 120°C and subsequently diluted with 1480 ml of hexane. Upon addition of the hexane, the mixture cooled further down to 67°C. The mixture was kept at this temperature for 2 hours and subsequently cooled down to room temperature. The resulting clear solution was stored under nitrogen atmosphere and was used as obtained. Analyses on the solution showed a titanium concentration of 0.25 mol / l. Preparation of the catalyst

[0060] In a 1.0 liter glass reactor, equipped with baffles, reflux condenser and stirrer, 286 ml hexanes and 170 ml of the complex from obtained above were dosed. The stirrer was set at 1400 rpm. In a separate flask, 75 ml of 50% ethyl aluminium dichloride (EADC) solution was added to 43 ml of hexanes. The resulting EADC solution was dosed into the reactor in 15 minutes using a peristaltic pump. Subsequently, the mixture was refluxed for 2 hours. After cooling down to ambient temperature, the obtained red / brown suspension was transferred to a glass P4 filter and the solids were separated. The solids were washed 4 times using 500 ml of hexanes. The solids were23POLY0140-WO-ORD 18 taken up in 0.3 L of hexanes and the resulting was stored under nitrogen. The solid content was 30 g / l.

[0061] Ti 9.7 wt% Mg 10.4 wt% Al 4.6 wt% Cl 49 wt% OEt 9.0 wt% and OBu 12 wt%.

[0062] Preparation of the ethylene polymer –

[0063] Inventive Example 1 (IE1) - A Continuous Stirred Tank Reactor (CSTR) reactor with 20 liters total volume and 15 liters of operating volume was operated at 88 °C and 7.3 barg total pressure. For producing a first polymer fraction, 750 g / h of ethylene and 0.98 g / h of hydrogen were added to the polymerization reactor, along with 4200 g / h of linear and branched C6 alkanes mixtures. In addition, Catalyst 1 was introduced into the reactor at the rate needed to keep the total pressure of the reactor constant, along with Tri-ethyl-aluminium (TEA) as cocatalyst. No additional comonomer was introduced into the reactor. The conditions in the reactor are shown in table 1.

[0064] The polymer slurry was withdrawn from the reactor and transferred to an adiabatic flash vessel were pressure was manipulated in order to get the desired H2 / C2 gas phase ratio in the second reactor. After this flashing step, the polymer slurry was withdrawn from the flash vessel and transferred to a second CSTR reactor with same total and operating volumes as the first CSTR reactor.

[0065] The second CSTR reactor was operated at 82 °C and 4.9 barg total pressure. Into the reactor were introduced ethylene at a rate of 390 g / h, linear and branched C6 alkanes mixtures at a rate of 4000 g / h, 1- butene at a rate of 90 g / h and nitrogen in order to keep the total pressure constant at 4.8 barg. The conditions in the second CSTR reactor are shown in Table 1. The slurry withdrawn from the second CSTR reactor was transferred into a centrifugal decanter where the polymer and diluent were separated.

[0066] Inventive example 2 (IE2) - Inventive examples 2 was identical to inventive example 1 except that the polymerization conditions and feeds are as shown in Table 1.

[0067]

[0068] Comparative examples 2 to 4 Comparative example 1 is a commercial polypropylene material while comparatives examples 2 to 4 are commercial high density polyethylene for injection molding applications.23POLY0140-WO-ORD 19

[0069] Processing parameters for of ethylene polymer – Table 1 IE1 IE2 Catalyst Cat1 Cat1 Cocatalyst TEA TEA First CSTR reactor Temperature (ºC) 88 88 Pressure (barg) 7.3 8.4 C6 alkane mixture feed 4200 4200 (g / h) Ethylene feed (g / h) 750 750 Hydrogen feed (g / h) 0.98 0.9 1-Hexene feed (g / h) 0 0 Polymer split (wt%) - 65.9 66.0 Low molecular weight component (A) as a % of total ethylene polymer Ethylene gas phase 22.8 24.2 (mol%) Hydrogen gas phase 48.7 49.2 (mol%) Nitrogen gas phase 12.4 13.7 (mol%) Ethane gas phase 0.94 0.86 (mol%) H2 / C2 gas phase ratio 2.14 2.03 (mol / mol) MI1.2 (g / 10min) 48.4 38.1 Density (kg / m3) ~970.1 ~968.2 Second CSTR reactor Temperature (ºC) 82 8223POLY0140-WO-ORD 20 Pressure (barg) 4.9 5.0 C6 alkane mixture feed 4000 4000 (g / h) Ethylene feed (g / h) 390 410 Hydrogen feed (g / h) 0.038 0.075 1-Butene feed (g / h) 90 1-Hexene feed (g / h) 0 320 Polymer split (wt%) 34.1 34.0 Ethylene gas phase 21.2 27.7 (mol%) Hydrogen gas phase 2.94 5.02 (mol%) Nitrogen gas phase 47.1 43.3 (mol%) Ethane gas phase 0.34 0.34 (mol%) 1-Butene gas phase 2.9 0 (mol%) 1-Hexene gas phase 0 - (mol%)

[0070] The resulting ethylene polymer was then dried under vacuum at 60 ºC overnight. The dry polymer was stabilized with 3000 ppm of a mixture of Calcium Stearate, Irgafos 168 and Irganox 1010 in weight ratio 50 / 37.5 / 12.5 respectively and then extruded into pellets in a Coperion ZSK-18 co-rotating twin screw extruder system, so that the extruder throughput was 1.8 kg / h and obtain the pellets of the polyethylene composition.

[0071] The results of the properties of the pellets of the polyethylene composition are shown in Table 3. Various properties of the pellets of the polyethylene composition of IE1 to IE2 and CEx1 to CEx4 were measured as in Table 3.23POLY0140-WO-ORD 21

[0072] The extrusion conditions for the ethylene polymer to obtain the polyethylene composition are as given below – Table 2 Extrusion Zone Temperature ºC Zone 1 85 Zone 2 160 Zone 3 245 Zone 4 265 Zone 5 265 Zone 6 265 Tm ~268-273 RPM 175 rpm Table 3 IE1 IE2 CE1 - CE4 – CE2 - CE3 – QR67 CC860 CC3054 M1053 3K V (HDPE) (HDPE) (PP) (HDPE) MI5 (g / 10min) 10.46 11.73 MI21.6 (g / 10min) 164.8 178.8 642.76 235.62 191.3 Melt Flow Ratio (21.6 / 5.0) 15.76 15.24 Density (kg / m3) 959.1 905 954 953 960 Comonomer 1- 1- 1- 1- 1- Butene Hexene Butene Butene Butene Comonomer content (mol%) 0.65 0.39 1 0.9 0.3 Mn (kg / mol) 10 10 37 10 11 11 Mw (kg / mol) 120 110 215 63 75 79 Mz (kg / mol) 1100 1100 600 1400 670 640 Mw / Mn 12.4 11.6 5.8 6.1 7.1 7.1 η100(Pa s) 704 665 233 159 351 423 η5000(Pa s) 53 56.6 25 51 70 74 LCBIndex0.7 0.31 0.68 0.76 Yield Stress (MPa) 27.6 25 26 26 30 Tensile Modulus (MPa) 1354 1050 1100 1100 130023POLY0140-WO-ORD 22 SH (MPa) 14.1 0 6.2 0.0 Bell Test F50 (h) 88 0.0 4.6 4.8

[0073] Hinged caps (components) of the materials on Table 3 were produced in a Husky injection machine H120-RS35 / 28 with a 4-cavity hinge cap mold. The machine has a clamping force of 120 tons and is equipped with a standard 3-zone screw of 28mm diameter and a L / D of 25.1. The hinge cap was designed based on a PCO-1881 screw cap with a diameter of 28mm but incorporating a typical bi-stable flip-top hinge with middle living hinge of 0.3mm thick and side hinge of 0.4mm thick. The hinge cap tool worked with both PP (polypropylene) and HDPE materials. There was an in-mold-closing unit integrated in the tool, which enabled to close the caps in the tool before the caps was ejected. Table 4 IE1 IE2 CE1 - CE3 – CE4 – QR673K CE2 - CC3054 (MIT085) (MIT083B) (HDPE M1053 CC860V (PP) ) (HDPE) (HDPE) Cycle time [s] 9.24 9.26 10 9.9 9.9 9.9 Processing temperature [°C] 220 220 230 205 205 220 Mold temperature [°C] 13 13 13 13 13 13 Injection speed [cm3 / s] 40 40 39 35 35 40 Injection pressure during cap injection [bar] 1634 1624 660 1099 1715 1787 molding

[0074] The results are provided below: Table 5 Sample IE1 CE1 - CE3 – CE4 – Unit IE2 CE2 - CC3054 Description (MIT085) (MIT083B) QR673K M1053 CC860V (PP) (HDPE) (HDPE) (HDPE)23POLY0140-WO-ORD 23 Open / close cycles without failure after 3 days conditioning [cycle] 120 97 120 0 0 0 @40 °C in 10%Igepal solution. Hinge bending fatigue test More [number of cycles [cycle] 4000 3000 than 2000 4500 1700 before hinge 5000 failure] Hinge twist break torque [N^cm] 39 38 43 30 30 41

[0075] It can be concluded that the polyethylene composition according to the invention (IE1 to IE2) has a combination of excellent processability due to the low viscosity values at both shear rates of, 100 rad / s and 5000 rad / s (η100 and η5000 respectively), a superior hinge resistance, given the high number of cycles without fracture, and very high stiffness, given by the density, yield stress and tensile modulus values. In comparison, samples derived from the high density polyethylene comparative examples (CE2-CE4) do not deliver enough resistance for the hinge cap application.

[0076] The ethylene copolymer according to the invention delivers similar performance to CE1 for hinge caps but with the added benefit of delivering monomaterial solutions for the bottle-cap system, enabling higher efficiency in recyclability.

[0077] Measurement methodology of various parameters:

[0078] MFI was measured according to ISO 1133-1:2011 under a load of 1.2 kg (MI1.2), 2.16 kg (MI5) or 21.6 kg (MI21.6) at 190°C. The term Melt Flow Index and Melt Flow Rate (MFR) may for example be used interchangeably for the purposes of the present invention.

[0079] Density - Density of polymer powder samples (ethylene polymer) was measured by preparing polymer test plaques of 40 x 40 x 1.6 mm, following ISO 17855-2 in a Fontyne press model TP200. The compression cycle has a temperature set at 180 C, with 10 minutes of contact pressure.23POLY0140-WO-ORD 24

[0080] Cooling was performed with time of 30 seconds without pressure increase, followed by pressure increase until 200 kN and maintaining the pressure level during the time needed for the sample to reach 23 C at a cooling rate of 15 ± 2 °C / min. Mass of the test plaque was determined in air (Analytical Balance XS104 Mettler Toledo). Subsequently, the test plaque was immersed in 4 liters of water at 100 °C (Automatic Densimeter D-H100 from Toyo Seiki equipped with a thermostatic bath MX7LR-20 from WMR) for 10 minutes after which the heat was turned off and the sample was cooled down to room temperature. The density was determined as follows: ^^^ೞ,ೌ^^∙ఘ^ೌ^^^^ൌ^ೞ,ೌ^^ି^^ೞశ^^,^ೌ^^^ି^^^,^ೌ^^^^^ 0.0027^^^= Density of the test plaque (g / cm³) ^^^,^^^= Mass of the test plaque in air (g) ^^௪^௧^^= Density of demineralized water (g / cm³) at test temperature (23°C) ^^^ା^^,௪^௧^^= Mass of the test plaque and sinker in water (g) ^^^^,௪^௧^^= Mass of the sinker clamp in water (g) Note: since density of polyethylene is lower than water, a sinker is used to keep the test plaque immersed.

[0081] Density of polymer pellet samples (polyethylene composition) was measured by following ISO 1183 A with the immersion method.

[0082] Comonomer content using Infrared method - Samples were pressed into 70 micron films using a Specac Atlas manual hydraulic press constant thickness film maker. Press temperature is set to 170 °C, preheat time is 1 minute, press time is 1 minute, press pressure was 2 tons and the spacer was an E-ring. Films were pressed in between PTFE foils.

[0083] Samples were subsequently measured via Infrared with a Perkin Elmer Spectrum 100 in transmission measurement mode.9 scans are made in the scan rage 4400-400 cm-1with an spectral resolution of 4 cm-1with CO2 / H20 water correction active.

[0084] The infrared results are transformed into comonomer mol% by the use of 6 calibration (calibration type multivariate), and 3 validation sample standards in the comonomer range 0.25 to 1.75 mol%.POLY0140-WO-ORD 25 Molecular weight (MW) and MWD

[0085] Mw, Mn and Mz were measured in accordance with ASTM D6474-12 (Standard Test Method for Determining molecular weight distribution and molecular weight Averages of Polyolefins by High Temperature Gel Permeation Chromatography). Mw stands for the weight average molecular weight and Mn stands for the number average molecular weight. Mz stands for the z-average molecular weight.

[0086] A high-temperature chromatograph Polymer Char GPC-IR system equipped with IR5 MCT detector and Polymer Char viscometer (Polymer Char S.A., Spain) was used at 160°C to determine the MWD and SCB as function of molecular weight. Three columns of Polymer Laboratories 13µm PLgel Olexis, 300 x 7.5mm, were used in series for GPC separation. 1,2,4-trichlorobenzene stabilized with 1g / L butylhydroxytoluene (also known as 2,6-di-tert-butyl-4-methylphenol or BHT) was used as eluent at a flow rate of 1mL / min. Sample concentration was around 0.7mg / mL and injection volume was 300µL.

[0087] The molar mass was determined based on the Universal GPC-principle using a calibration made with PE narrow and broad standards (in the range of 0.5–2800kg / mol, Mw / Mn - 4 to 15) in combination with known Mark Houwink constants of PE-calibrant (alfa = 0.725 and log K = -3.721).

[0088] Deconvolution technique to calculate Mw / Mn for the high molecular weight polymer component B using ASTM D 6474-12

[0089] The molecular weight distribution moments for the polymer component B (Mn and Mw) can be calculated by using a deconvolution technique employing the data obtained experimentally using the ASTM D 6474-12 standard for the low molecular weight component (Component A) and the final polyethylene composition. Such techniques for example has been described in WO99 / 14271.

[0090] For polymers manufactured using a Ziegler-Natta catalyst system such as the ones employed for the inventive examples of the invention, Cat1 and Cat2, the molecular weight distribution follows a log-normal distribution, defined by Equation [3]:POLY0140-WO-ORD 26Where: wi is the weight component of polymer with molecular weight Mi M0 is the peak molecular weight β is a parameter which characterizes the width of the log-normal distribution

[0091] The MWD deconvolution technique involves a two parameter fit, M0 and β, as per equation [3]. Both parameters values are fitted by minimizing the error defined by Eqn 4.

[0092] This is the error between the experimentally determined molecular weight distribution for the polyethylene composition (final product) obtained using ASTM D 6474- 12, and the fitted distribution obtained by the addition of fractions A and B of the final composition.

[0093] The molecular weight distribution data for fraction A and for the final composition was obtained by using ASTM D 6474-12 on the collected inventive examples of Table 1, and molecular weight distribution data for fraction B was calculated from the molecular weight distribution data from final polyethylene composition and fraction A, as described below.

[0094] The minimization error is expressed as: ^^^^^^^^^^ ൌ ∑^ ൫^^ െ ^ଶ^ୀ^ ^,^௫^^^^^^^௧^^ ^^,^^^^௨^^௧^ௗ൯[4]wi,experimentalis the weight fraction of polymer with a molecular weight Mifor the polymer composition of the invention. It is determined experimentally for the polyethylene composition following ASTM D 6474-12. wi,calculated is the weight fraction of polymer with a molecular weight Mi calculated for the polyethylene composition of the invention.

[0095] It is determined from the addition of the weight fraction of polymer with same molecular weight Mi for the fraction A, determined experimentally following ASTM D 6474- 12, times the weight component of polymer fraction A in the total polyethylene composition and the addition of the weight fraction of polymer with same molecular weight Mifor the fraction B, calculated with Equation [3], times the weight component of polymer fraction B in23POLY0140-WO-ORD 27 the final polyethylene composition. The components of fractions A and B with respect to the total polyethylene composition can be found for each inventive example in Table 1. The error was minimized by using Solver Excel minimization algorithm iterating over the values of M0and β.

[0096] Mn and Mw for the calculated molecular weight distribution of component B are calculated by the formulas described in ASTM D 6474-12.

[0097] Peak ratio: A ratio of the value of the peak of the molecular weight distributions of the low molecular weight component (A) and the value of the peak of the high molecular weight component (B) was calculated as follows: The molecular weight distribution for the high molecular weight component (B) and the low molecular weight component (A) was resolved by deconvolution of the ethylene polymer molecular weight distribution. There after using known split values the value was determined using the equation – ^^^^^ / ^^^^^^^^^^^^^^^^^ ^^^^ ,^^^^^ ൈ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^ ^^^^^^^^^^^^^^^^^^ൌ^^^^^ / ^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^,^^^^^^^^ ൈ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[0098] Then, the ratio value was calculated from the dW / dLogMw value at the peak molecular weight of the low molecular weight component multiplied by the corresponding molecular weight component. Dynamic Mechanical Properties (complex viscosity η):

[0099] The viscosity values at each shear rate are calculated by fitting flow curves generated by oscillatory reometer according to ISO 6721-10 between 0.01 and 100 rad / s at 190 C on parallel plates with 25 mm diameter and 1.2 mm gap with a modified Carreau-Yasuda model, which is represented by the following equation: ^^ ൌ ^^ ^^షభ ^∙ ^1 ^ ^^^ ∙ ^^^ ^ೌ[1]η is the viscosity in Pa.s η0 is the zero shear viscosity (Pa.s)23POLY0140-WO-ORD 28 a is the rheological breadth parameter n is the power law constant, set to 0 in the present case (defines the slope of the high shear rate region) γ is the shear rate (1 / s) λ is the relaxation time (s) η100 is the viscosity value in Pa.s at 190 ºC and a shear rate of 100 rad / s as calculated by equation [1] previously fitted to the flow curve data generated by oscillatory rheometry between 100 and 5000 rad / s at 190 ºC according to ISO 6721-10 on parallel plates with 25 mm diameter and 1.2 mm gap.

[0100] To facilitate model fitting, the power law constant is held at a constant value, in this case zero. Details of the significance and interpretation of the Carreau-Yasuda model and derived parameters may be found in: C.A. Hieber and H.H. Chiang, Rheol Acta, 28, 321 (1989); C.A. Hieber and H.H. Chiang, Polym. Eng. Sci., 32, 931 (1992); and R.B. Bird, R.C. Armstrong and O. Hasseger, Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2ndEdition, John Wiley & Sons (1987). For complex viscosity at 5000 rad / s, the data is obtained by extrapolation using the methodology described in the patent (Carreau Yasuda equation) and the data used for the extrapolation is obtained following ISO 6721-10 at 190 ºC. Determination of Long Chain Branching

[0101] Long Chain Branching in polyethylene can for example be determined through the relationship between low or zero-shear viscosity and molecular weight as shown in J. Janzen, R.H. Colby, Journal of Molecular Structure, 485-489 (1999). The cited reference is included only for the purpose of establishing that that there is a relationship between the long chain branching in polyethylene and low or zero shear viscosity and the molecular weight. One such relationship that can be used for the purpose of the invention is as below [2]:

[0102] Long Chain Branching content of the polyethylene composition of the invention has been characterized by the following relationship: ^^^^^^ூ^ௗ^௫ൌఎబ.బభ^య.లమవల∙^^^ಾ^^ష^.యరయవ [2]23POLY0140-WO-ORD 29 where:

[0103] LCBIndex diagnoses the amount of Long Chain Branching present in the polymer. η0.01is the viscosity of the polymer at 190 ºC and 0.01 rad / s in Pa*s measured according to the procedure described in the document. Mw is the weight average molecular weight of the polymer measured according to the procedure described in the document and expressed in kg / mol.

[0104] Yield stress is measured following ISO 527-1 at 1 mm / min for modulus and at 50 mm / min for the tensile test, on bars of type 1B, with average results from 5 specimens at 23 °C.

[0105] Strain hardening modulus was determined according to ISO18488.

[0106] Impact Resistance: Impact resistance was measured by Charpy method following ISO 179-1 / 1eA, non instrumented test at -10 °C, 0 °C and 23 °C on specimens with dimensions 80 x 10 x 4 mm and a notch of type A. The result obtained was the average of 5 specimens that was tested. The direction of the blow is edgewise. Specimens were prepared by compression molding following ISO17855-2, at a compression molding temperature of 180 °C, with a compression molding cooling rate of 15 °C / min and a plaque thickness of 4 mm. Final specimens were prepared by machining from the compression molded plaque.

[0107] ESCR test for the hinge The ESCR performance of the hinge samples were evaluated in the following way: the samples were immersed in an aqueous solution of 10% Igepal; and thereafter conditioning the samples in an oven at 0°C for 3 days. Thereafter, evaluating the performance of the samples by taking the samples out of the Igepal solution and opening and closing the caps manually until failure or up to 120 cycles. The Table below shows the ESCR test results, with the reported average number of bending cycles until hinge failure or up to 120 cycles.

[0108] Hinge fatigue performance: The fatigue performance of the hinge samples were evaluated by flexing the hinge using a bending tester. The base part and the flip-top part of thePOLY0140-WO-ORD 30 cap were clamped separately by the the base part was bended along the hinge while the flip-top was fixed and not moved. The base part of the hinge samples were bent from 180° (open) to an angle of 30° that is close to the closing position. Each hinge sample was bent until a hinge failure was observed or reached 5000 times of bending. The results are provided in Table 4.

Claims

23POLY0140-WO-ORD 31 CLAIMS 1. A polyethylene composition, comprising an ethylene polymer comprising or consisting of : a) ≥ 60.0 and ≤ 75.0 wt.%, preferably ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000, preferably wherein the weight average molecular weight (Mw) is determined in accordance with ASTM D6474-12; and b) ≥ 25.0 and ≤ 40.0 wt.%, preferably ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; preferably wherein the low molecular weight component (A) is an ethylene homopolymer or an ethylene copolymer and preferably wherein the high molecular weight component (B) is a copolymer of ethylene and a C3-C20comonomer, preferably the high molecular weight component (B) is a copolymer of ethylene and a C3-C8alpha olefin; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and ^ a density of ≥ 954.0 and ≤ 965.0 kg / m3, preferably ≥ 954.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC.

2. The polyethylene composition according to claim 1, wherein the polyethylene composition comprises a melt flow ratio of ≥ 10.0 and ≤ 30.0, preferably ≥ 12.0 and ≤ 22.0, preferably ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and at 5.0 kg respectively.POLY0140-WO-ORD 32 3. The polyethylene composition to any one of claims 1-2, wherein the polyethylene composition has a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 45.0 Pa.s and ≤ 65.0 Pa.s, preferably ≥ 48.0 Pa.s and ≤ 60.0 Pa.s, preferably ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC 4. The polyethylene composition according to any one of claims 1-3, wherein the polyethylene composition has a total content of polymeric units derived from C3-C8alpha olefin of ≥ 0.35 and ≤ 0.85 mol.%, preferably ≥ 0.35 and ≤ 0.75 mol.%, with regard to the total moles of the polyethylene composition, preferably wherein the mole content of the polymeric units in the polyethylene composition is determined using InfraRed spectroscopy.

5. The polyethylene composition according to any one of claims 1-4, wherein the C3-C8 alpha olefin comonomer is 1-hexene, and preferably wherein the total content of polymeric units derived from 1-hexene comonomer is from ≥ 0.35 and ≤ 0.50 mol.%, with regard to the total moles of the polyethylene composition.

6. The polyethylene composition according to any one of claims 1-5, wherein the polyethylene composition has weight average molecular weight (Mw) of ≥ 100 kg / mol and ≤ 200 kg / mol, preferably ≥ 100 kg / mol and ≤ 180 kg / mol, preferably ≥ 105 kg / mol and ≤ 130 kg / mol, determined in accordance with ASTM D6474-12.

7. The polyethylene composition according to any one of claims 1-6, wherein the polyethylene composition has a Z-average molecular weight (Mz) of ≥ 700 kg / mol and ≤ 1500 kg / mol, preferably ≥ 1000 kg / mol and ≤ 1200 kg / mol determined in accordance with ASTM D6474-12.

8. The polyethylene composition according to any one of claims 1-7, wherein the polyethylene composition has a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 25.0, preferably ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight23POLY0140-WO-ORD 33 average molecular weight and Mn is number average molecular weight as determined in accordance with ASTM D6474-12.

9. The polyethylene composition according to any one of claims 1-8, wherein the polyethylene composition has a Strain Hardening modulus of ≥ 8.0 MPa and ≤ 25.0 MPa, preferably ≥ 12.0 MPa and ≤ 22.0 MPa, preferably ≥ 12.0 MPa and ≤ 20.0 MPa, as measured in accordance with ISO 18488.

10. The polyethylene composition according to any one of claims 1-9, wherein polyethylene composition, comprises the ethylene polymer comprising or consisting of : a) ≥ 62.0 and ≤ 68.0 wt.%, with regard to the total weight of the ethylene polymer, of a low molecular weight component (A) having a weight average molecular weight of ≥ 10,000 g / mol and ≤ 70,000; and b) ≥ 32.0 and ≤ 38.0 wt.%, with regard to the total weight of the ethylene polymer, of a high molecular weight component (B) having a weight average molecular weight of ≥ 100,000 g / mol and ≤ 700,000 g / mol; wherein the polyethylene composition has: ^ a melt flow index (MFI21.6) of ≥ 140.0 and ≤ 185.0 dg / min, preferably ≥ 150.0 and ≤180.0 dg / min, preferably ≥ 160.0 and ≤ 180.0 dg / min, determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 21.6 kg; and ^ a density of ≥ 954.0 and ≤ 965.0 kg / m3, preferably ≥ 954.0 and ≤ 962.0 kg / m3, preferably ≥ 957.0 and ≤ 961.0 kg / m3, determined in accordance with ISO 1183; and ^ a complex viscosity (η100) at a shear rate of 100 rad / s of ≥ 580 and ≤ 715 Pa.s, preferably ≥ 580 and ≤ 700 Pa.s, preferably ≥ 585 and ≤ 680 Pa.s determined in accordance with ISO 6721-10 at 190 ºC; and ^ a complex viscosity (η5000) at a shear rate of 5000 rad / s of ≥ 45.0 Pa.s and ≤ 65.0 Pa.s, preferably ≥ 48.0 Pa.s and ≤ 60.0 Pa.s, preferably ≥ 50.0 Pa.s and ≤ 58.0 Pa.s, determined in accordance with ISO 6721-10 at 190 ºC; andPOLY0140-WO-ORD 34 ^ a melt flow ratio of ≥ 12.0 and ≤ 22.0, ≥ 14.0 and ≤ 20.0, where melt flow ratio is the ratio of melt flow index measured according to ISO1133-1:2011 at 190 ºC and at 21.6 and 5.0 kg respectively; and ^ a molecular weight distribution (Mw / Mn) of ≥ 10.0 and ≤ 25.0, preferably ≥ 10.0 and ≤ 20.0, preferably ≥ 10.0 and ≤ 18.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight as determined in accordance with ASTM D6474-12.

11. The polyethylene composition according to any one of claims 1-10, wherein the polyethylene composition has at least one of: (a) a Bell Test resistance F50 of > 50 hours and < 300 hours when determined in accordance with ASTM D1693 Method B at 50 ºC in 10% IGEPAL; and / or (b) a Yield stress of ≥ 26.0 MPa and ≤ 35.0 MPa, preferably ≥ 26.0 MPa and ≤ 32.0 MPa, preferably ≥ 26.5 MPa and ≤ 31.0 MPa as measured according to ISO 527-2 at 23 ºC; and / or (c) a tensile modulus value of ≥ 1350 MPa and ≤ 1550 MPa, preferably ≥ 1380 MPa and ≤ 1450 MPa as measured according to ISO 527-2 at 23 ºC.

12. The polyethylene composition according to any one of claims 1-11, wherein the polyethylene composition comprises ≥ 80.0 wt.% and ≤ 100.wt.%, preferably ≥ 90.0 wt.% and ≤ 100.wt.%, preferably ≥ 95.0 wt.% and ≤ 100.wt.%, preferably ≥ 98.0 wt.% and ≤ 100.wt.% of the ethylene polymer with regard to the total weight of the polyethylene composition; and wherein the polyethylene composition comprises ≥ 0.0 wt.% and ≤ 20.0 wt.%, preferably ≥ 0.0 wt.% and ≤ 10.0 wt.%, preferably ≥ 0.0 wt.% and ≤ 5.0 wt.%, preferably ≥ 0.0 wt.% and ≤ 2.0 wt.%, of additives with regard to the total weight of the polyethylene composition, preferably wherein the additives are selected from anti- oxidants, carbon black, fillers, process stabilisers, anti-oxidants, light and / or heat stabilisers, cross-linking agents and combinations thereof.POLY0140-WO-ORD 35 13. An article comprising the as claimed in claims 1-12.

14. The article of claim 13, wherein the article is a hinge component.

15. Use of the polyethylene composition as claimed in claims 1-13, for improving the properties of stiffness, processability during injection molding, hardness and environmental stress cracking resistance (ESCR), of an article, preferably wherein the article is a hinge component.

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