Process for producing polyethylene composition for oriented polyethylene film, polyethylene composition and film thereof

Abstract

A process for producing a polyethylene composition oriented film comprising: providing from 60 to 90 wt% of a linear low density polyethylene resin; the linear low density polyethylene resin has an MI2 in the range of from 0.9 to 4.0 g / 10 min; a density ranging from 0.910 to 0.930 g / cm3; an Mw / Mn of at least 2.5; a z average molecular weight (Mz) of up to 310, 000 g / mol; and the linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers wherein the one or more comonomers are present in a content ranging from 7.0 to 11.0 wt% based on the linear low density polyethylene resin; providing from 10 to 40 wt% of a high density polyethylene resin; the high density polyethylene resin has an MI2 in the range of from 0.5 to 1.6 g / 10 min; a density ranging from 0.950 to 0.965 g / cm3; and melt blending the linear low density polyethylene resin with the high density polyethylene resin to produce a polyethylene composition.

Description

Technical Field

[0001] The present disclosure relates to polyethylene compositions and articles made from such polyethylene compositions, such as oriented films (ie, biaxially oriented polyethylene films or mono-oriented polyethylene films). The present disclosure also relates to processes for producing the polyethylene compositions. Background Art

[0002] Polyethylene compositions comprising linear low-density polyethylene (LLDPE) are known from the prior art for producing oriented films.

[0003] For example, US8247065 discloses blends of linear low density polyethylene (LLDPE) copolymers with very low density, low density, medium density, high density (HDPE) and differentiated polyethylene and other polymers. The document discloses the use of metallocene-catalyzed LLDPE in such blends, wherein the LLDPE preferably has a comonomer content of up to about 5 mol%; MI2 ranging from 0.1 to 300 g / 10 min; melt index ratio from 15 to 45, Mw from 20,000 to 200,000 g / mol, Mw / Mn ranging from 2.0 to 4.5, Mz / Mw ranging from 1.7 to 3.5 and Mz / Mw ranging from 0.910 to 0.955 g / cm 3 Density. LLDPE-HDPE blends are also disclosed, wherein HDPE may be present in a content ranging from 0.1 to 99.9 wt %. In Examples 63-84 of US8247065, the content of HDPE is 10 wt %. The HDPE resin used is produced by a conventional metallocene catalyst, has a narrow MWD, and is a homopolymer with a melt index ranging from 1 up to 200 g / 10 min. Films produced from these blends are also produced. It exhibits an interesting balance of properties, but there is still a need to improve the balance of properties. For example, optical properties or impact resistance may be improved. In addition, the document does not mention sealing properties such as hot tack.

[0004] The present disclosure aims to provide solutions to one or more of the above-mentioned shortcomings and problems. In particular, the present disclosure provides polyethylene compositions for oriented films and processes for producing such polyethylene compositions, which allow obtaining an improved balance of properties including mechanical properties (such as stiffness or impact resistance), processability, optical properties and sealing properties (such as hot tack properties) compared to non-oriented PE films. Summary of the invention

[0005] Surprisingly, it has been found that the above mentioned objects can be achieved individually or in any combination by using specific polyethylene compositions in biaxially oriented polyethylene (BOPE) films or monooriented polyethylene (MDO) films.

[0006] According to a first aspect, the present disclosure provides a process for producing a polyethylene composition for a biaxially oriented polyethylene film or a monooriented polyethylene film, which is notable in that it comprises:

[0007] - providing from 60 to 90 wt% of a linear low density polyethylene resin, based on the total weight of the polyethylene composition; wherein the linear low density polyethylene resin has: an MI2 ranging from 0.9 to 4.0 g / 10 min when measured at 190°C under a load of 2.16 kg according to ISO 1133-2005; and a MI2 ranging from 0.910 to 0.930 g / cm when measured at 23°C according to ISO 1183-1:2012. 3 a density of at least 2.5 when measured by gel permeation chromatography; a z-average molecular weight (Mz) of at most 310,000 g / mol when measured by gel permeation chromatography; and the linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers, wherein the one or more comonomers are present in an amount ranging from 7.0 to 11.0 weight percent based on the linear low density polyethylene resin.

[0008] - providing from 10 to 40 wt% of a high density polyethylene resin, based on the total weight of the polyethylene composition; wherein the high density polyethylene resin has: an MI2 ranging from 0.5 to 1.6 g / 10 min when measured at 190°C under a load of 2.16 kg according to ISO 1133-2005; and a MI2 ranging from 0.950 to 0.965 g / cm when measured at 23°C according to ISO 1183-1:2012. 3 wherein the high density polyethylene resin is selected to have an MI2 that is lower than (below, below...) or equal to the MI2 of the linear low density polyethylene resin; and

[0009] - melt blending the linear low density polyethylene resin with the high density polyethylene resin to produce a polyethylene composition.

[0010] In one embodiment, the process includes providing from 65 to 85 wt % of the linear low density polyethylene resin, based on the total weight of the polyethylene composition.

[0011] In one embodiment, the process includes providing from 15 to 35 wt % of a high density polyethylene resin, based on the total weight of the polyethylene composition.

[0012] One or more of the following may be used to further define the linear low density polyethylene resin (LLDPE).

[0013] For example, the LLDPE is a copolymer of ethylene and one or more comonomers selected from propylene, 1-butene, 1-hexene, and 1-octene; preferably selected from 1-butene, 1-hexene, and 1-octene.

[0014] For example, the LLDPE is a copolymer of ethylene and one or more comonomers, wherein the one or more comonomers are present in a content ranging from 7.5 to 9.5 wt % based on the linear low density polyethylene resin.

[0015] For example, the LLDPE has a MI2 ranging from 1.0 to 3.5 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0016] For example, when measured at 23°C according to ISO 1183-1:2012, the LLDPE has a range of from 0.912 to 0.928 g / cm 3 density.

[0017] For example, the LLDPE has a Mw / Mn ranging from 3.5 to 6.0 when determined by gel permeation chromatography.

[0018] For example, the LLDPE has a z-average molecular weight (Mz) ranging from 180,000 to 280,000 g / mol when determined by gel permeation chromatography.

[0019] For example, the LLDPE is metallocene-catalyzed.

[0020] For example, the LLDPE has a bimodal molecular weight distribution.

[0021] One or more of the following may be used to further define the high density polyethylene resin (HDPE).

[0022] For example, the HDPE has a MI2 ranging from 0.6 to 1.5 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0023] For example, when measured at 23°C according to ISO 1183-1:2012, the HDPE has a range of from 0.952 to 0.964 g / cm 3 density.

[0024] According to a second aspect, the present disclosure provides a polyethylene composition, notably produced by a process according to the first aspect.

[0025] According to a third aspect, the present disclosure provides a polyethylene composition, notable in that it has:

[0026] - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg;

[0027] - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density;

[0028] - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography;

[0029] - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography;

[0030] - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and

[0031] - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

[0032] According to a third aspect, the present disclosure provides a film, which is a monolayer film or a multilayer film, which is notable in that at least one of the one or more layers is made of a polyethylene composition according to the second aspect or according to the third aspect; and the film is a biaxially oriented polyethylene film or a uniaxially oriented polyethylene film.

[0033] The following may be used to further define the polyethylene composition according to the first, second or third aspect or for use in a film according to the fourth aspect.

[0034] Preferably, the polyethylene composition has

[0035] - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg;

[0036] - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density;

[0037] - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography;

[0038] - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography;

[0039] - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and

[0040] - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

[0041] For example, the polyethylene composition has a MI2 ranging from 1.0 to 2.6 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0042] For example, the polyethylene composition has a molecular weight ranging from 0.920 to 0.935 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 density.

[0043] For example, when passing 13 The polyethylene composition has a comonomer content ranging from 4.9 to 8.5 wt %, based on the total weight of the polyethylene composition, as determined by C-NMR analysis.

[0044] For example, the polyethylene composition has a main melting temperature peak Tm of at least 120°C when measured according to ISO 11357-3:2018.

[0045] For example, in the TREF curve, the polyethylene composition has two elution peaks from 60 to 120°C.

[0046] For example, in the TREF curve, the polyethylene composition has a main elution peak below 85°C and a secondary elution peak above 95°C.

[0047] For example, the polyethylene composition has from 60 to 90 wt % polymer eluting at temperatures ranging from 50 to 95°C, and from 10 to 40 wt % polymer eluting at temperatures ranging from above 95 to 120°C, based on the total weight of the polymer.

[0048] For example, the polyethylene composition has a Mw / Mn ranging from 3.2 to 5.8 when determined by gel permeation chromatography.

[0049] For example, the polyethylene composition has a Mz / Mw ranging from 2.0 to 5.0 when measured by gel permeation chromatography.

[0050] For example, the polyethylene composition has a z-average molecular weight (Mz) of up to 350,000 g / mol when determined by gel permeation chromatography.

[0051] According to a fifth aspect, the present disclosure provides a process for producing a biaxially oriented polyethylene film according to the fourth aspect, comprising:

[0052] a) producing a polyethylene composition having:

[0053] - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg;

[0054] - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density;

[0055] - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography;

[0056] - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography;

[0057] - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and

[0058] - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

[0059] b) extruding or casting a film comprising the polyethylene composition

[0060] c) stretching the film in the machine direction and in the transverse direction to produce a biaxially oriented polyethylene film, wherein the stretch ratio in the machine direction is from 4.5 to 7.0 and the stretch ratio in the transverse direction is in the range of from 6.0 to 10.0; preferably, the stretch ratio in the machine direction is from 5.0 to 6.0 and / or the stretch ratio in the transverse direction is in the range of from 7.5 to 9.5.

[0061] In one embodiment, step b) comprises extruding or casting a film having a thickness ranging from 500 μm to 1.5 mm when measured by DIN ISO 4593: 1993.

[0062] In one embodiment, stretching the film in the machine and transverse directions is performed by sequential stretching, wherein stretching is performed in the machine direction followed by stretching in the transverse direction.

[0063] In one embodiment, stretching the film in the machine direction and the transverse direction is performed by stretching in both directions simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 Shown is a graph plotting the TREF (Temperature Rising Elution Fractionation) of polyethylene compositions according to the present disclosure.

[0065] Figure 2 Indicates hot tack sealing properties. DETAILED DESCRIPTION

[0066] When describing the polymers, uses and processes of the present disclosure, the terms employed are to be understood by the following definitions unless the context indicates otherwise. For the present disclosure, the following definitions are provided:

[0067] As used herein, the singular forms "a", "an", and "the" include singular and plural referents unless the context dictates otherwise. As an example, "a resin" means one resin or more than one resin.

[0068] As used herein, the terms "comprising" and "consisting of" are synonymous with "including" or "containing", and are inclusive or open-ended and do not exclude additional unrecited members, elements, or method steps. It will be understood that as used herein, the terms "comprising" and "consisting of" include the term "consisting of".

[0069] Numerical ranges expressed by endpoints include all integers and, where appropriate, fractions contained within the range (e.g., 1 to 5 may include 1, 2, 3, 4, 5 when referring to, for example, the number of elements, and may also include 1.5, 2, 2.75, and 3.80 when referring to, for example, measured values). The description of endpoints also includes the endpoint values ​​themselves (e.g., from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all subranges contained therein.

[0070] All references cited in this specification are incorporated herein by reference in their entirety. In particular, the teachings of all references specifically mentioned herein are incorporated by reference.

[0071] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of the present disclosure. Thus, the phrases "in one embodiment" or "in an embodiment" appearing in multiple places throughout this specification do not necessarily all refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, as will be apparent to those skilled in the art from this disclosure, the particular features, structures, or characteristics may be combined in any suitable manner. Furthermore, although some embodiments described herein include some other features that are not included in other embodiments, the combination of features of different embodiments is intended to be within the scope of the present disclosure and to form different embodiments, as will be understood by those skilled in the art.

[0072] The terms "polyethylene" (PE) and "ethylene polymer" may be used synonymously. The term "polyethylene" encompasses ethylene homopolymers as well as ethylene copolymer resins, which may be derived from ethylene and one or more comonomers selected from C3-C 20 α-Olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene.

[0073] The term "high density polyethylene", which may be abbreviated as "HDPE", is generally used to refer to polyethylene having a density of at least 0.940 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 Density polyethylene.

[0074] The term "polyethylene resin", "ethylene homopolymer resin" or "ethylene copolymer resin" refers to polyethylene fluff or powder, which is extruded and / or melted and / or pelletized and can be produced by compounding and homogenizing the polyethylene resin as taught herein, for example with a mixing and / or extruder device. As used herein, the term "polyethylene" can be used as an abbreviation for "polyethylene resin". The term "fluff" or "powder" refers to a polyethylene material having hard catalyst particles at the core of each grain, and is defined as the polymer material after it leaves a polymerization reactor (or the final polymerization reactor in the case of multiple reactors connected in series).

[0075] Under normal production conditions in a production facility, it is expected that the melt index (MI2, HLMI, MI5) of the fluff will be different from that of the polyethylene resin. Under normal production conditions in a production facility, it is expected that the density of the fluff will be slightly different from that of the polyethylene resin. Unless otherwise indicated, the density and melt index of the polyethylene resin refer to the density and melt index measured on the polyethylene resin as defined above.

[0076] The present disclosure provides a process for producing a polyethylene film for biaxial orientation or a monooriented polyethylene film, which is notable in that it comprises:

[0077] - providing from 60 to 90 wt% of a linear low density polyethylene resin, based on the total weight of the polyethylene composition; wherein the linear low density polyethylene resin has: an MI2 ranging from 0.9 to 4.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg; a density ranging from 0.910 to 0.930 g / cm3 when measured according to ISO 1183-1:2012 at 23°C; an Mw / Mn of at least 2.5 when measured by gel permeation chromatography; a z-average molecular weight (Mz) of up to 310,000 g / mol when measured by gel permeation chromatography; and the linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers, wherein the one or more comonomers are present in an amount ranging from 7.0 to 11.0 wt% based on the linear low density polyethylene resin.

[0078] - providing from 10 to 40 wt% of a high density polyethylene resin, based on the total weight of the polyethylene composition; wherein the high density polyethylene resin has: an MI2 ranging from 0.5 to 1.6 g / 10 min when measured at 190°C under a load of 2.16 kg according to ISO 1133-2005; and a MI2 ranging from 0.950 to 0.965 g / cm when measured at 23°C according to ISO 1183-1:2012.3 wherein the high density polyethylene resin is selected to have an MI2 less than or equal to the MI2 of the linear low density polyethylene resin; and

[0079] - melt blending the linear low density polyethylene resin with the high density polyethylene resin to produce a polyethylene composition.

[0080] In a preferred embodiment, the process comprises providing from 62 to 88 wt%, preferably from 65 to 85 wt%, more preferably from 68 to 82 wt%, and even more preferably from 70 to 80 wt% of the linear low density polyethylene resin, based on the total weight of the polyethylene composition.

[0081] In a preferred embodiment, the process comprises providing from 12 to 38 wt%; preferably from 15 to 35 wt%; more preferably from 18 to 32 wt%; and even more preferably from 20 to 30 wt% of the linear low density polyethylene resin, based on the total weight of the polyethylene composition.

[0082] The present disclosure also provides a process for producing a biaxially oriented polyethylene film comprising:

[0083] a) producing a polyethylene composition having:

[0084] - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg;

[0085] - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density;

[0086] - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography;

[0087] - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography;

[0088] - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and

[0089] - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

[0090] b) extruding or casting a film comprising the polyethylene composition

[0091] c) stretching the film in the machine direction and in the transverse direction to produce a biaxially oriented polyethylene film, wherein the stretch ratio in the machine direction is from 4.5 to 7.0 and the stretch ratio in the transverse direction is in the range of from 6.0 to 10.0; preferably, the stretch ratio in the machine direction is from 5.0 to 6.0 and / or the stretch ratio in the transverse direction is in the range of from 7.5 to 9.5.

[0092] In one embodiment, step b) comprises extruding or casting a film having a thickness ranging from 500 μm to 1.5 mm when measured by DIN ISO 4593.

[0093] In one embodiment, stretching the film in the machine and transverse directions is performed by sequential stretching, wherein stretching is performed in the machine direction followed by stretching in the transverse direction.

[0094] In one embodiment, stretching the film in the machine direction and in the transverse direction is performed by stretching in both directions simultaneously.

[0095] Selection of linear low density polyethylene resin

[0096] According to the present disclosure, the linear low density polyethylene resin (LLDPE) is selected to have an MI2 ranging from 0.9 to 4.0 g / 10 min when measured at 190° C. under a load of 2.16 kg according to ISO 1133-2005; and ranging from 0.910 to 0.930 g / cm when measured at 23° C. according to ISO 1183-1:2012. 3 a density of at least 2.5 when measured by gel permeation chromatography; a z-average molecular weight (Mz) of at most 310,000 g / mol when measured by gel permeation chromatography; and the linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers, wherein the one or more comonomers are present in an amount ranging from 7.0 to 11.0 weight percent based on the linear low density polyethylene resin.

[0097] For example, the linear low density polyethylene resin is selected to have an MI2 of at least 0.9 g / 10 min; preferably at least 1.0 g / 10 min; more preferably at least 1.1 g / 10 min; even more preferably at least 1.2 g / 10 min; most preferably at least 1.3 g / 10 min; and even most preferably at least 1.4 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0098] For example, the linear low density polyethylene resin is selected to have an MI2 of at most 4.0 g / 10 min; preferably at most 3.8 g / 10 min; more preferably at most 3.5 g / 10 min; even more preferably at most 3.2 g / 10 min; most preferably at most 3.0 g / 10 min and even most preferably at most 2.8 g / 10 min or at most 2.5 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0099] Preferably, the linear low density polyethylene resin is selected to have an MI2, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg, ranging from 0.9 to 4.0 g / 10 min; preferably from 0.9 to 3.8 g / 10 min; more preferably from 1.0 to 3.5 g / 10 min; even more preferably from 1.1 to 3.2 g / 10 min; most preferably from 1.2 to 3.0 g / 10 min and even most preferably from 1.3 to 2.8 g / 10 min or from 1.4 to 2.5 g / 10 min.

[0100] For example, the linear low density polyethylene resin is selected to have a carbon content of at least 0.910 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 ; preferably, at least 0.912 g / cm 3 More preferably, at least 0.914 g / cm 3 ; Even more preferably, at least 0.915 g / cm 3 ; and most preferably at least 0.916 g / cm 3 density.

[0101] For example, the linear low density polyethylene resin is selected to have a molecular weight of at most 0.930 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3; preferably, at most 0.928 g / cm3; more preferably, at most 0.925 g / cm 3 ; even more preferably, at most 0.923 g / cm 3 ; and most preferably, at most 0.920 g / cm 3 density.

[0102] Preferably, the linear low density polyethylene resin is selected to have a molecular weight in the range of from 0.910 to 0.930 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 ; preferably, from 0.912 to 0.928 g / cm 3 More preferably, from 0.914 to 0.925 g / cm 3 ; Even more preferably, from 0.915 to 0.923 g / cm 3 ; and most preferably from 0.916 to 0.920 g / cm 3 density.

[0103] The linear low density polyethylene resin is preferably a copolymer of ethylene and one or more comonomers. Suitable comonomers include but are not limited to aliphatic C3-C 20 α-olefins. Suitable aliphatic C3-C 20 Examples of α-olefins include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene. Preferably, the one or more comonomers are selected from propylene, 1-butene, 1-hexene and 1-octene. Preferably, the one or more comonomers are selected from propylene, 1-butene and 1-hexene. More preferably, the comonomer is 1-butene and / or 1-hexene.

[0104] The term "copolymer" refers to polymers made by linking ethylene and at least one comonomer in the same polymer chain.

[0105] Preferably, when 13 The linear low density polyethylene is an ethylene copolymer and comprises at least 7.0 wt %; preferably at least 7.2 wt %; more preferably at least 7.5 wt %; even more preferably at least 7.8 wt %; most preferably at least 8.0 wt %; even most preferably at least 8.2 wt % of one or more comonomers, based on the total weight of the linear low density polyethylene resin, as determined by C-NMR analysis.

[0106] Preferably, when 13The linear low density polyethylene is an ethylene copolymer and contains up to 11.0 wt %; preferably up to 10.0 wt %; preferably up to 9.5 wt %; more preferably up to 9.0 wt %; and even more preferably up to 8.8 wt % of one or more comonomers, based on the total weight of the linear low density polyethylene resin, when determined by C-NMR analysis.

[0107] In a preferred embodiment, when 13 The one or more comonomers are present in the linear low density polyethylene resin in an amount ranging from 7.0 to 11.0 wt %; preferably from 7.2 to 10.0 wt %; more preferably from 7.5 to 9.5 wt %; and even more preferably from 8.0 to 9.0 wt % based on the total weight of the linear low density polyethylene resin, when determined by C-NMR analysis.

[0108] In one embodiment, the linear low density polyethylene is metallocene catalyzed.

[0109] In one embodiment, the linear low density polyethylene resin has a multimodal or bimodal molecular weight distribution.

[0110] For example, the linear low density polyethylene resin has a Mw / Mn of at least 2.5, preferably at least 2.7, preferably at least 3.0, preferably at least 3.2, preferably at least 3.5, preferably at least 3.6, more preferably at least 3.8, even more preferably at least 4.0, and most preferably at least 4.2, as determined by gel permeation chromatography.

[0111] For example, the linear low density polyethylene resin has a Mw / Mn of at most 6.0; preferably, at most 5.8; more preferably, at most 5.5; even more preferably at most 5.2; most preferably at most 5.0, when measured by gel permeation chromatography.

[0112] For example, when measured by gel permeation chromatography, the linear low density polyethylene resin has a Mw / Mn ranging from 2.7 to 6.0; preferably ranging from 3.5 to 6.0; more preferably ranging from 4.0 to 5.0.

[0113] For example, the linear low density polyethylene resin has a z-average molecular weight (Mz) of at most 310,000 g / mol; preferably at most 300,000 g / mol; more preferably at most 280,000 g / mol; and even more preferably at most 260,000 g / mol, as determined by gel permeation chromatography.

[0114] For example, the linear low density polyethylene resin has a z-average molecular weight (Mz) of at least 160,000 g / mol; preferably at least 180,000 g / mol; more preferably at least 200,000 g / mol; and even more preferably at least 220,000 g / mol, as determined by gel permeation chromatography.

[0115] For example, when measured by gel permeation chromatography, the linear low density polyethylene resin has a z-average molecular weight (Mz) ranging from 160,000 to 310,000 g / mol; preferably, from 180,000 to 280,000 g / mol.

[0116] For example, the linear low density polyethylene resin has an Mw of at most 110,000 g / mol; preferably, at most 100,000 g / mol; more preferably, at most 95,000 g / mol; and even more preferably, at most 90,000 g / mol, when measured by gel permeation chromatography.

[0117] For example, the linear low density polyethylene resin has an Mw of at least 60,000 g / mol; preferably, at least 65,000 g / mol; more preferably, at least 70,000 g / mol; and even more preferably, at least 75,000 g / mol, as determined by gel permeation chromatography.

[0118] Selection of high density polyethylene resin

[0119] The high density polyethylene resin has an MI2 ranging from 0.5 to 1.6 g / 10 min when measured at 190° C. under a load of 2.16 kg according to ISO 1133-2005, and ranging from 0.950 to 0.965 g / cm2 when measured at 23° C. according to ISO 1183-1:2012. 3 density.

[0120] For example, the high density polyethylene resin is selected to have an MI2 of at least 0.5 g / 10 min; preferably at least 0.6 g / 10 min; more preferably at least 0.7 g / 10 min; even more preferably at least 0.8 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0121] For example, the high density polyethylene resin is selected to have an MI2 of at most 1.6 g / 10 min; preferably at most 1.5 g / 10 min; more preferably at most 1.4 g / 10 min; even more preferably at most 1.3 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0122] Preferably, the high density polyethylene resin is selected to have an MI2 in the range of from 0.5 to 1.6 g / 10 min; preferably from 0.6 to 1.5 g / 10 min; more preferably from 0.7 to 1.4 g / 10 min; even more preferably from 0.8 to 1.3 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0123] For example, the high density polyethylene resin is selected to have a density of at least 0.950 g / cm 3 ; preferably, at least 0.952 g / cm 3 More preferably, at least 0.954 g / cm 3 ; and even more preferably, at least 0.955 g / cm 3 density.

[0124] For example, the high density polyethylene resin is selected to have a density of at most 0.965 g / cm 3 ; preferably, at most 0.964 g / cm 3 More preferably, at most 0.962 g / cm 3 ; and even more preferably, at most 0.960 g / cm 3 density.

[0125] Preferably, the high density polyethylene resin is selected to have a molecular weight in the range of from 0.950 to 0.965 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 ; preferably, from 0.952 to 0.964 g / cm 3 ; More preferably, from 0.954 to 0.962 g / cm 3 ; and even more preferably, from 0.955 to 0.960 g / cm 3 density.

[0126] The high density polyethylene resin is selected from homopolymers and copolymers of ethylene and one or more comonomers; preferably a homopolymer.

[0127] Suitable comonomers include, but are not limited to, aliphatic C3-C 20 α-olefins. Suitable aliphatic C3-C 20 Examples of α-olefins include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene. Preferably, the one or more comonomers are selected from propylene, 1-butene, 1-hexene and 1-octene. Preferably, the one or more comonomers are selected from propylene, 1-butene and 1-hexene. More preferably, the comonomer is 1-butene and / or 1-hexene.

[0128] The term "copolymer" refers to a polymer made by linking ethylene and at least one comonomer in the same polymer chain. The term "homopolymer" refers to a polymer made in the absence of a comonomer or with less than 0.1 wt%, more preferably less than 0.05 wt% of a comonomer.

[0129] Preferably, the high density polyethylene is an ethylene copolymer and when 13 When measured by C-NMR analysis, the high density polyethylene contains at least 0.1 wt.%, preferably at least 0.5 wt.%, more preferably at least 0.8 wt.%, even more preferably at least 1.0 wt.%, most preferably at least 1.2 wt.%, and even most preferably at least 1.5 wt.% of one or more comonomers, based on the total weight of the high density polyethylene.

[0130] Preferably, the high density polyethylene is an ethylene copolymer and when 13 The high density polyethylene comprises at most 2.5 wt %; preferably at most 2.2 wt %; more preferably at most 2.0 wt %; and even more preferably at most 1.8 wt % of one or more comonomers, based on the total weight of the high density polyethylene, when determined by C-NMR analysis.

[0131] In a preferred embodiment, when 13 When measured by C-NMR analysis, the one or more comonomers are present in the high density polyethylene in an amount ranging from 0.1 to 2.5 weight percent; preferably from 0.5 to 2.5 weight percent; more preferably from 0.8 to 2.2 weight percent; and even more preferably from 1.0 to 2.2 weight percent, based on the total weight of the high density polyethylene.

[0132] For example, HDPE is chromium-catalyzed, Ziegler-Natta-catalyzed, or metallocene-catalyzed.

[0133] Polyethylene composition

[0134] Preferably, the linear low density polyethylene resin and the high density polyethylene resin and their respective contents are selected so that the polyethylene composition has an MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190° C. under a load of 2.16 kg, and a MI2 ranging from 0.915 to 0.935 g / cm2 when measured according to ISO 1183-1:2012 at 23° C. 3 a density of 3.0 to 6.0 when measured by gel permeation chromatography; a z-average molecular weight (Mz) of up to 370,000 g / mol when measured by gel permeation chromatography; and a molecular weight of 1.5 to 1.5 g / mol when measured by gel permeation chromatography. 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

[0135] For example, the polyethylene composition has a MI2 of at least 0.9 g / 10 min; preferably at least 1.0 g / 10 min; and more preferably at least 1.1 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0136] For example, the polyethylene composition has an MI2 of at most 3.0 g / 10 min; preferably at most 2.8 g / 10 min; more preferably at most 2.6 g / 10 min; even more preferably at most 2.4 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0137] Preferably, the polyethylene composition has a MI2 in the range of from 0.9 to 3.0 g / 10 min; preferably from 0.9 to 2.8 g / 10 min; more preferably from 1.0 to 2.6 g / 10 min; even more preferably from 1.1 to 2.4 g / 10 min, when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0138] For example, the polyethylene composition has a hardness of at least 0.920 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 ; preferably, at least 0.922 g / cm 3 More preferably, at least 0.924 g / cm 3 ; and even more preferably, at least 0.925 g / cm 3 density.

[0139] For example, the polyethylene composition has a molecular weight of at most 0.935 g / cm 3 ; preferably, at most 0.934 g / cm 3 More preferably, at most 0.932 g / cm 3 ; and even more preferably, at most 0.930 g / cm 3 density.

[0140] Preferably, the polyethylene composition has a molecular weight in the range of from 0.915 to 0.935 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 ; preferably, from 0.920 to 0.934 g / cm 3 ; More preferably, from 0.924 to 0.932 g / cm 3 ; and even more preferably, from 0.925 to 0.930 g / cm 3 density.

[0141] Preferably, when 13 When determined by C-NMR analysis, the polyethylene composition comprises at least 4.2 wt%, preferably at least 4.5 wt%, more preferably at least 4.9 wt%, even more preferably at least 5.0 wt%, most preferably at least 5.2 wt%, even most preferably at least 5.5 wt% or at least 5.7 wt% of one or more comonomers, based on the total weight of the polyethylene composition.

[0142] Preferably, when 13 The polyethylene composition comprises at most 9.1 wt%; preferably at most 8.5 wt%; more preferably at most 7.5 wt%; and even more preferably at most 6.5 wt% of one or more comonomers, based on the total weight of the polyethylene composition, when determined by C-NMR analysis.

[0143] In a preferred embodiment, when 13 When measured by C-NMR analysis, the one or more comonomers are present in the polyethylene composition in an amount ranging from 4.2 to 9.1 wt%; preferably from 4.5 to 9.2 wt%; more preferably from 4.9 to 8.5 wt%; even more preferably from 5.0 to 7.5 wt% and most preferably from 5.2 to 6.5 wt% based on the total weight of the polyethylene composition.

[0144] For example, in the TREF curve, the polyethylene composition has two elution peaks from 60 to 120° C., excluding a purge peak.

[0145] For example, in the TREF curve, the polyethylene composition has a main elution peak below 85° C. Preferably, in the TREF curve, the polyethylene composition has a main elution peak below 82° C., preferably below 80° C.

[0146] For example, in the TREF curve, the polyethylene composition has a secondary elution peak above 95° C. Preferably, in the TREF curve, the polyethylene composition has a main elution peak above 98° C., preferably above 100° C.

[0147] For example, based on the total weight, the polyethylene composition has from 60 to 90 wt% of polymer eluted at a temperature ranging from 50 to 95°C, and from 10 to 40 wt% of polymer eluted at a temperature ranging from above 95 to 120°C; preferably, based on the total weight, from 65 to 85 wt% of polymer eluted at a temperature ranging from 50 to 95°C, and from 15 to 35 wt% of polymer eluted at a temperature ranging from above 95 to 120°C.

[0148] For example, the polyethylene composition has a Mw / Mn of at least 3.0; preferably, at least 3.2; more preferably, at least 3.5; even more preferably, at least 3.8; most preferably at least 4.0, when determined by gel permeation chromatography.

[0149] For example, the polyethylene composition has a Mw / Mn, when determined by gel permeation chromatography, of at most 6.0; preferably, at most 5.8; more preferably, at most 5.5; even more preferably at most 5.2; most preferably at most 5.0.

[0150] For example, the polyethylene composition has a Mw / Mn ranging from 3.0 to 6.0; preferably ranging from 4.0 to 5.0, when determined by gel permeation chromatography.

[0151] For example, the polyethylene composition has a z-average molecular weight (Mz) of at most 370,000 g / mol; preferably at most 360,000 g / mol, more preferably at most 350,000 g / mol; even more preferably at most 320,000 g / mol; and most preferably at most 300,000 g / mol, when determined by gel permeation chromatography.

[0152] For example, the polyethylene composition has a z-average molecular weight (Mz) ranging from 180,000 to 370,000 g / mol, preferably ranging from 200,000 to 350,000 g / mol, when determined by gel permeation chromatography.

[0153] For example, the polyethylene composition has an Mz / Mw of at least 2.0, preferably at least 2.2, more preferably at least 2.5, when measured by gel permeation chromatography. For example, the polyethylene composition has an Mz / Mw of at most 5.0, preferably at most 4.5, most preferably at most 4.0, and even most preferably at most 3.5, when measured by gel permeation chromatography. For example, the polyethylene composition has an Mz / Mw ranging from 2.0 to 5.0, preferably ranging from 2.2 to 4.0, when measured by gel permeation chromatography.

[0154] For example, the polyethylene composition has a main melting temperature peak Tm of at least 120°C; preferably at least 122°C, more preferably at least 124°C, when measured according to ISO 11357-3:2018.

[0155] The polyethylene composition according to the present disclosure may contain one or more additives, such as, for example, antioxidants, light stabilizers, acid scavengers, flame retardants, lubricants, antistatic additives, nucleating agents / clarifiers, colorants, slip agents, antiblocking agents, processing aids, and any mixtures thereof. Such that producing the polyethylene composition may include blending polyethylene with one or more additives to obtain the polyethylene composition.

[0156] For example, the polyethylene composition according to the present disclosure may contain one or more antioxidants, such as a primary antioxidant and / or a secondary antioxidant. It is believed that the one or more antioxidants do not affect the tensile behavior nor the final film mechanical properties.

[0157] Typical commercial primary antioxidants are hindered phenols and secondary aromatic amines. The most common secondary antioxidants are trivalent phosphorus compounds (phosphites).

[0158] In a preferred embodiment, the polyethylene composition comprises from 100 to 5000 ppm of one or more antioxidants based on the total weight of the polyethylene composition. Preferably, the one or more antioxidants comprise at least one phenolic antioxidant and / or at least one organic phosphite or phosphite (salt) antioxidant.

[0159] Preferably, the polyethylene composition comprises at least 100 ppm; preferably at least 150 ppm, more preferably at least 200 ppm; even more preferably at least 250 ppm and most preferably at least 300 ppm of one or more antioxidants, based on the total weight of the polyethylene composition.

[0160] Preferably, the polyethylene composition comprises at most 5000 ppm; preferably at most 4000 ppm; more preferably at most 3000 ppm; even more preferably at most 2500 ppm and most preferably at most 2000 ppm of one or more antioxidants, based on the total weight of the polyethylene composition.

[0161] Preferably, the polyethylene composition comprises from 100 to 5000 ppm; preferably from 150 to 4000 ppm; more preferably from 200 to 3000 ppm; even more preferably from 250 to 2500 ppm; and most preferably from 300 to 2000 ppm of one or more antioxidants, based on the total weight of the polyethylene composition.

[0162] In a preferred embodiment, the one or more antioxidants are or comprise one or more phenolic antioxidants, and the one or more phenolic antioxidants are selected from octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (CAS No. 2082-79-3, Irganox® 1076) and / or pentaerythritol-tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl) propionate) (CAS 6683-19-8, Irganox® 1010).

[0163] Preferably, the polyethylene composition comprises at least 100 ppm; preferably at least 150 ppm, more preferably at least 200 ppm; even more preferably at least 250 ppm and most preferably at least 300 ppm of one or more phenolic antioxidants, based on the total weight of the polyethylene composition.

[0164] Preferably, the polyethylene composition comprises at most 5000 ppm; preferably at most 4000 ppm, more preferably at most 3000 ppm; even more preferably at most 2500 ppm and most preferably at most 2000 ppm of one or more phenolic antioxidants, based on the total weight of the polyethylene composition.

[0165] The polyethylene composition comprises from 100 to 5000 ppm, preferably from 150 to 4000 ppm, more preferably from 200 to 3000 ppm, even more preferably from 250 to 2500 ppm, and most preferably from 300 to 2000 ppm of one or more phenolic antioxidants selected from octadecyl 3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate and / or pentaerythritol-tetrakis(3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate), based on the total weight of the polyethylene composition.

[0166] In a preferred embodiment, the one or more antioxidants are or comprise at least one organic phosphite or phosphonite antioxidant selected from tris(2,4-di-tert-butylphenyl)phosphite (CAS No. 31570-04-4, Irgafos® 168), bis(2,4-di-tert-butyl-6-methylphenyl)-ethyl-phosphite (CAS No. 145650-60-8, Irgafos® 38), trisnonylphenyl phosphite (CAS No. 26523-78-4), tetrakis-(2,4-di-tert-butylphenyl)-4,4'-biphenyl-diphosphonite (CAS No. 119345-01-6, Irgafos® P-EPQ), 2,4,6-tri-tert-butylphenyl 2-butyl-2-ethyl-1,3-propanediol phosphite (CAS No. 161717-32-4, Ultranox® 641), and any mixture thereof.

[0167] Preferably, the polyethylene composition comprises at least 100 ppm; preferably at least 150 ppm, more preferably at least 200 ppm; even more preferably at least 250 ppm and most preferably at least 300 ppm of one or more organophosphite or phosphonite antioxidants, based on the total weight of the polyethylene composition.

[0168] Preferably, the polyethylene composition comprises at most 5000 ppm; preferably at most 4000 ppm, more preferably at most 3000 ppm; even more preferably at most 2500 ppm and most preferably at most 2000 ppm of one or more organophosphite or phosphonite antioxidants, based on the total weight of the polyethylene composition.

[0169] Based on the total weight of the polyethylene composition, the polyethylene composition comprises from 100 to 5000 ppm; preferably from 150 to 4000 ppm; more preferably from 200 to 3000 ppm; even more preferably from 250 to 2500 ppm; and most preferably from 300 to 2000 ppm. ppm of one or more organic phosphites or phosphonite antioxidants selected from tris(2,4-di-tert-butylphenyl)phosphite (CAS No. 31570-04-4, Irgafos® 168), bis(2,4-di-tert-butyl-6-methylphenyl)-ethyl-phosphite (CAS No. 145650-60-8, Irgafos® 38), trisnonylphenylphosphite (CAS No. 26523-78-4), tetrakis-(2,4-di-tert-butylphenyl)-4,4'-biphenyl-diphosphonite (CAS No. 119345-01-6, Irgafos® P-EPQ), 2,4,6-tri-tert-butylphenyl 2-butyl-2-ethyl-1,3-propanediol phosphite (CAS No. 161717-32-4, Ultranox® 641), or a mixture thereof.

[0170] In one embodiment, the one or more antioxidants include one or more selected from pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]; tris(2,4-di-tert-butylphenyl)phosphite and / or octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0171] In one embodiment, the one or more antioxidants include at least two selected from pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl)phosphite and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0172] Pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate] is commercially available as Irganox® 1010 from BASF. Tris(2,4-di-tert-butylphenyl)phosphite is commercially available as Irgafos® 168 from BASF. Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is commercially available as Irganox® 1076 from BASF.

[0173] For example, the polyethylene composition according to the present disclosure may contain one or more acid scavengers. It is believed that the one or more acid scavengers do not affect the tensile behavior nor the mechanical properties of the final film.

[0174] Preferably, the polyethylene composition comprises from 10 to 5000 ppm; preferably from 50 to 4000 ppm; more preferably from 100 to 3000 ppm; even more preferably from 200 to 2500 ppm; and most preferably from 300 to 2000 ppm of one or more acid scavengers, based on the total weight of the polyethylene composition.

[0175] Preferably, the one or more acid scavengers are selected from calcium oxide, zinc oxide, calcium stearate, magnesium stearate, zinc stearate, sodium stearate, potassium stearate, hydrotalcite, and mixtures thereof, preferably selected from calcium stearate, magnesium stearate, zinc stearate, sodium stearate, potassium stearate, and mixtures thereof, more preferably selected from calcium stearate, calcium oxide, zinc oxide, and any mixtures thereof. Preferably, the one or more acid scavengers are or comprise calcium stearate.

[0176] For example, the polyethylene composition may contain one or more slip agents. Any slip agent known to those skilled in the art may be added. Non-limiting examples of slip agents include primary amides having from about 12 to about 40 carbon atoms (e.g., erucamide, oleamide, stearamide, and behenamide); secondary amides having from about 18 to about 80 carbon atoms (e.g., stearyl erucamide, behenyl erucamide, methyl erucamide, and ethyl erucamide); secondary-bis-amides having from about 18 to about 80 carbon atoms (e.g., ethylene-bis-stearamide and ethylene-bis-oleamide); and combinations thereof. For example, the one or more slip agents are selected from polymethylsiloxane, erucamide, oleamide, stearamide, behenamide, stearyl erucamide, behenyl erucamide, methyl erucamide, ethyl erucamide, ethylene-bis-stearamide, ethylene-bis-oleamide, and any combination thereof. Non-limiting examples of commercially available slip agents have trade names such as ATMER from Uniqema, Everberg, Belgium. ™ SA; ARMOSLIP® from Akzo Nobel Polymer Chemicals, Chicago, IL; KEMAMIDE® from Witco, Greenwich, CT; and CRODAMIDE® from Croda, Edison, NJ.

[0177] Preferably, the polyethylene composition comprises from 10 to 5000 ppm, preferably from 50 to 4000 ppm; more preferably from 100 to 3000 ppm; even more preferably from 200 to 2500 ppm; and most preferably from 300 to 2000 ppm of one or more slip agents, based on the total weight of the polyethylene composition.

[0178] For example, the polyethylene composition may contain one or more antiblocking agents. The antiblocking agent can be used to prevent undesirable adhesion between contact layers of an article made of the polymer composition, particularly under moderate pressure and heat during storage, manufacture or use. Any antiblocking agent known to those of ordinary skill in the art can be added to the polyethylene composition disclosed herein. Non-limiting examples of antiblocking agents include minerals (e.g., clay, chalk, and calcium carbonate), synthetic silica gels (e.g., SYLOBLOC® from Grace Davison, Columbia, MD), natural silicas (e.g., SUPER FLOSS® from Celite Corporation, Santa Barbara, CA), talc (e.g., OPTIBLOC® from Luzenac, Centennial, CO), zeolites (e.g., SIPERNAT® from Degussa, Parsippany, NJ), aluminosilicates (e.g., SILTON® from Mizusawa Industrial Chemicals, Tokyo, Japan), limestone (e.g., CARBOREX® from Omya, Atlanta, GA), spherical polymer particles (e.g., EPOSTAR® poly(methyl methacrylate) particles from Nippon Shokubai, Tokyo, Japan, and TETRAPOL® from GE Silicones, Wilton, TN), and poly(methacrylate) particles from GE Silicones, Wilton, TN). CT's TOSPEARL® silicone particles), waxes, amides (e.g., erucamide, oleamide, stearamide, behenamide, ethylene-bis-stearamide, ethylene-bis-oleamide, stearyl erucamide and other slip agents), molecular sieves, and combinations thereof.

[0179] Preferably, the polyethylene composition comprises from 10 to 5000 ppm; preferably from 50 to 4000 ppm; more preferably from 100 to 3000 ppm; even more preferably from 200 to 2500 ppm; and most preferably from 300 to 2000 ppm of one or more antiblocking agents, based on the total weight of the polyethylene composition.

[0180] For example, the polyethylene composition may contain one or more processing aids. For example, the one or more processing aids are selected from fluoroelastomers, waxes, tristearin, zinc stearate, calcium stearate, magnesium stearate, erucamide, oleamide, ethylene-acrylic acid copolymer, ethylene vinyl acetate copolymer, cetyltrimethylammonium bromide, polyethylene oxide, polysiloxane, oleamide, stearamide, behenamide, oleyl palmitamide, ethylenebis-oleamide, ethylenebis(stearamide) (EBS), and any mixture thereof.

[0181] Preferably, the polyethylene composition comprises from 10 to 5000 ppm; preferably from 50 to 4000 ppm; more preferably from 100 to 3000 ppm; even more preferably from 200 to 2500 ppm; and most preferably from 300 to 2000 ppm of one or more processing aids, based on the total weight of the polyethylene composition.

[0182] Test Method

[0183] Polyethylene resin Melt flow index MI2 Determined according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

[0184] Polyethylene resin HLMI Determined according to ISO 1133-2005 at 190°C under a load of 21.6 kg.

[0185] Mn, Mw, Mz, Mw / Mn and Mz / Mw: Molecular weight n (number average molecular weight), M w (weight average molecular weight) and molecular weight distribution D (Mw / Mn) are determined by size exclusion chromatography (SEC) and in particular by gel permeation chromatography (GPC). Briefly, a GPC-IR5 from Polymer Char is used: 10 mg of polyethylene sample is dissolved in 10 mL of trichlorobenzene at 160°C for 1 hour. Injection volume: about 400 µl, automatic sample preparation and injection temperature: 160°C. Column temperature: 145°C. Detector temperature: 160°C. Two Shodex AT-806MS (Showa Denko) and one Styragel HT6E (Waters) columns are used with a flow rate of 1 ml / min. Detector: Infrared detector (2800-3000 cm -1 Calibration: narrow standard of polystyrene (PS) (commercially available). The molecular weight Mi of each fraction i of the eluted polyethylene was calculated based on the Mark-Houwink relationship (log 10 (M PE)=0.965909 × log 10 (M PS ) - 0.28264)(at the low molecular weight end in M PE =1000).

[0186] The average molecular weight used to establish molecular weight / property relationships is the number average molecular weight (M n ), weight average molecular weight (M w ) and z-average molecular weight (M z ). These averages are defined by the following expressions and are calculated by M i Sure:

[0187]

[0188]

[0189]

[0190] Here N i and W i are the number and weight of molecules with molecular weight Mi, respectively. The third representation (rightmost) in each case defines how these averages were obtained from the SEC chromatogram. i is the height of the SEC curve at the i-th elution fraction (from the baseline), and M i is the molecular weight of the substance eluting in that increment.

[0191] Then Molecular weight distribution (MWD) Calculated as Mw / Mn.

[0192] 13 C-NMR analysisUse 400 MHz or 500 MHz Bruker NMR spectrometer to carry out under the condition that the signal intensity in the spectrum is directly proportional to the total number of contributing carbon atoms in the sample. Such conditions are well known to those skilled in the art, and include, for example, sufficient relaxation times, etc. In practice, the intensity of the signal is obtained from its integration (i.e., corresponding area). Data are obtained as follows: use proton decoupling, use 10 mm room temperature probe (10 mm room temperaturethrough) each spectrum 2000 to 4000 scans or use 10 mm cryoprobe each spectrum 240 scans, 11 seconds of pulse repetition delay and 25000 Hz (+ / -3000 Hz) of the spectrum width. The samples were prepared by dissolving a sufficient amount of the polymer in 1,2,4-trichlorobenzene (TCB, 99%, spectroscopic grade) at 130°C with occasional stirring to homogenize the sample, followed by the addition of hexadeuterated benzene (C6D6, spectroscopic grade) and a small amount of hexamethyldisiloxane (HMDS, 99.5+%), where HMDS was used as an internal standard. To give an example, approximately 200 mg to 600 mg of the polymer was dissolved in 2.0 mL of TCB, followed by the addition of 0.5 mL of C6D6 and 2 to 3 drops of HMDS.

[0193] After data acquisition, chemical shifts were referenced to the signal of the internal standard HMDS, which was assigned a value of 2.03 ppm.

[0194] The comonomer content in the polyethylene was determined by the method described by GJ Ray et al. (Macromolecules, 1977, 10, (4), 773-778) by precipitating the pellets. 13 The content of MgCl2O3 was determined by C-NMR analysis.

[0195] Crystallization temperature (Tc) and melting temperature (Tm) is measured on a DSCQ2000 instrument of TA Instruments according to ISO 11357-3:2018. In order to eliminate the thermal history, the sample is first heated to 220°C and kept at 220°C for 3 minutes. The polymer is then cooled to a maximum of 20°C at -20°C / min and kept at 20°C for 3 minutes. The crystallization temperature is determined during this cooling step. The crystallization temperature Tc corresponds to the temperature of the extreme value of the spectrogram, which presents the heat flux associated with the polymer as a function of the temperature during its cooling. The polymer is then melted to a maximum of 220°C at 20°C / min, and the melting temperature is determined during this heating step. The melting temperature corresponds to the temperature of the extreme value of the spectrogram, which presents the heat flux associated with the polymer as a function of the temperature during its melting.

[0196] Measured according to the method of standard ISO 1183-1:2012 (immersion method) at a temperature of 23°C density .

[0197] Determined according to DIN ISO 4593:1993 Film thickness .

[0198] The film properties were determined according to ASTM D 882. Mechanical properties , such as tensile strength at break, elongation at break and E modulus.

[0199] Falling dart impact resistance was determined according to ASTM D1709, Method A.

[0200] The heat shrinkage was measured at a temperature of 100°C during 5 minutes with a sample size of 100 mm x 100 mm.

[0201] Determined according to ASTM D 1003 Haze Haze was measured on the final BOPE films: The thickness of these films is reported in Table 6.

[0202] Hot tack seal properties were determined according to ASTM F1921 / Method B under the following conditions:

[0203] Sample width: 15 mm

[0204] Sealing time: 3 s

[0205] Sealing pressure: 0.3 N / mm²

[0206] Pulling speed: 200 mm / s

[0207] TREF

[0208] Temperature rising elution fractionation analysis (TREF analysis) was performed using a method similar to that described in Soares and Hamielec, Polymer, 36 (10), 1995 1639-1654 (which is incorporated herein by reference in its entirety). TREF analysis was performed on a TREF model 200 TF series instrument equipped with an infrared detector from Polymer Char (Valencia, Spain). The sample was dissolved in 1,2-dichlorobenzene at 150° C. for 1 h. The following parameters were used as shown in the following table.

[0209]

[0210]

[0211] Example

[0212] The following non-limiting examples illustrate the present disclosure.

[0213] Selection of blend components

[0214] - LLDPE1 was prepared according to the process disclosed in WO2020078932 for use in the examples of the present invention. LLDPE1 was metallocene catalyzed. The comonomer was hexene and was present at about 8 wt%.

[0215] - HDPE1 is lumicene® M5510EP (batch S106319328), commercially available from TotalEnergies.

[0216] - HDPE2 is HD6207CC (batch H008E00380), commercially available from TotalEnergies.

[0217] - HDPE3 is an experimental resin and is Ziegler-Natta catalyzed.

[0218] - HDPE4 is an experimental resin and is Ziegler-Natta catalyzed.

[0219] The properties of the components of the blend are provided in Table 1 below.

[0220] Table 1

[0221]

[0222] The compositions of the blends and the properties of the blends are provided in Tables 2-4.

[0223] Table 2

[0224]

[0225] Blend 01 and Blend 02 blends were extruded / compounded prior to a BOPE pilot trial to ensure optimal homogeneity of the mixture.

[0226] Table 3:

[0227]

[0228] (1) The blends have multiple temperature peaks, and the main melting temperature peak is reported here.

[0229] Table 4: TREF results

[0230]

[0231] Multilayer film

[0232] A 5-layer BOPE film has been produced according to a sequential stretching process (tenter frame technology). All layers contain the same polyethylene composition.

[0233] In the first step, cast sheets were extruded using several extruders feeding 5 layers ("DBABC") according to Table 5 below.

[0234] Table 5:

[0235]

[0236] At the exit of the die, the coextruded sheet (about 1 mm thickness) was cooled on a cooling roll partially immersed in a water bath.

[0237] In the second step, the cast sheet passes through an MDO unit (machine direction orientation) where it is stretched in the machine direction by a system of heated rollers. The MD stretched film then enters a tenter frame (or "TDO oven"), which is an oven-like device that uses chains on turning rails to clamp and stretch the film in the transverse direction.

[0238] At the exit of the TD oven, the film reached its final thickness (ie, about 20 microns).

[0239] The properties of the BOPE films are reported in Table 6 as stretch ratios in the machine direction (MDx) and in the transverse direction (TDx).

[0240] Compared to thicker, non-oriented PE blown films, these thin BOPE films feature an improved balance of properties:

[0241] - Higher film stiffness and tensile strength at break despite lower thickness (tensile strength at break is typically in the range of 50 to 60 MPa for 40 micron blown film based on standard mPE with a density of 0.923-0.927);

[0242] - Similar to higher dart impact resistance despite lower thickness (based on standard mPE with density of 0.923-0.927, dart is typically in the range of 200 to 310 grams for 40 micron blown film);

[0243] - Clarity is similar to better (based on standard mPE with a density of 0.923-0.927, haze is typically in the range of 5% to 8% for 40 micron blown film).

[0244] The sealing properties of some BOPE films have been evaluated by means of a hot tack seal test, in comparison with a 40 micron thick PE blown film reference (either based on a commercial metallocene LLDPE with a density of 0.923, or based on a commercial LDPE with a density of 0.924). With regard to the seal initiation temperature (i.e. the lowest temperature at which a given seal strength is reached): considering a threshold of 0.2 to 0.5 N / 15 mm, the BOPE films of the invention show a higher or at least similar sealing force compared to the reference blown films. It can also be seen that the BOPE films allow to reach a higher maximum seal strength than the reference blown films (about 120°C above 2.0 N / 15 mm), despite their lower thickness, but with a relatively wide sealing window.

[0245] Hot-tack sealing properties provide Figure 2 middle.

[0246] In summary, it can be said that the BOPE films of the present invention exhibit an improved balance of properties (mechanical, optical and sealing) compared to thicker, non-oriented PE blown films.

[0247]

Claims

1. A process for producing a polyethylene composition for biaxially oriented polyethylene film or monoaxially oriented polyethylene film, characterized in that It includes: - providing from 60 to 90 wt% of a linear low density polyethylene resin, based on the total weight of the polyethylene composition; wherein the linear low density polyethylene resin has: an MI2 ranging from 0.9 to 4.0 g / 10 min when measured at 190°C under a load of 2.16 kg according to ISO 1133-2005; and a MI2 ranging from 0.910 to 0.930 g / cm when measured at 23°C according to ISO 1183-1:2012. 3 a density of at least 2.5 when measured by gel permeation chromatography; a z-average molecular weight (Mz) of at most 310,000 g / mol when measured by gel permeation chromatography; and the linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers, wherein the one or more comonomers are present in an amount ranging from 7.0 to 11.0 weight percent based on the linear low density polyethylene resin; - providing from 10 to 40 wt% of a high density polyethylene resin, based on the total weight of the polyethylene composition; wherein the high density polyethylene resin has: an MI2 ranging from 0.5 to 1.6 g / 10 min when measured at 190°C under a load of 2.16 kg according to ISO 1133-2005; and a MI2 ranging from 0.950 to 0.965 g / cm when measured at 23°C according to ISO 1183-1:2012. 3 wherein the high density polyethylene resin is selected to have an MI2 less than or equal to the MI2 of the linear low density polyethylene resin; and - melt blending the linear low density polyethylene resin with the high density polyethylene resin to produce a polyethylene composition.

2. The process according to claim 1, characterized in that The polyethylene composition has: - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg; - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density; - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography; - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography; - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

3. The process according to claim 2, characterized in that The polyethylene composition has a MI2 ranging from 1.0 to 2.6 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg.

4. The process according to claim 2 or 3, characterized in that The polyethylene composition has a molecular weight ranging from 0.920 to 0.935 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 density.

5. The process according to any one of claims 2 to 4, characterized in that When passing 13 The polyethylene composition has a comonomer content ranging from 4.9 to 8.5 wt %, based on the total weight of the polyethylene composition, as determined by C-NMR analysis.

6. The process according to any one of claims 2 to 5, characterized in that The polyethylene composition has a Mw / Mn ranging from 3.2 to 5.8 when measured by gel permeation chromatography.

7. The process according to any one of claims 2 to 6, characterized in that The polyethylene composition has a Mz / Mw ranging from 2.0 to 5.0 when measured by gel permeation chromatography.

8. The process according to any one of claims 2 to 7, characterized in that The polyethylene composition has a z-average molecular weight (Mz) of up to 350,000 g / mol when determined by gel permeation chromatography.

9. The process according to any one of claims 2 to 8, characterized in that The polyethylene composition has a main melting temperature peak Tm of at least 120°C when measured according to ISO 11357-3:2018.

10. The process according to any one of claims 1 to 9, characterized in that The process comprises: - providing from 65 to 85 wt% of a linear low density polyethylene resin, based on the total weight of the polyethylene composition; and / or - Based on the total weight of the polyethylene composition, providing from 15 to 35 wt% of a high density polyethylene resin.

11. The process according to any one of claims 1 to 10, characterized in that The linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers selected from 1-butene, 1-hexene, and 1-octene.

12. The process according to any one of claims 1 to 11, characterized in that The linear low density polyethylene resin is a copolymer of ethylene and one or more comonomers, wherein the one or more comonomers are present in a content ranging from 7.5 to 9.5 wt % based on the linear low density polyethylene resin.

13. The process according to any one of claims 1 to 12, characterized in that The linear low density polyethylene resin has an MI2 ranging from 1.0 to 3.5 g / 10 min when measured at 190° C. under a load of 2.16 kg according to ISO 1133-2005.

14. The process according to any one of claims 1 to 13, characterized in that The linear low density polyethylene resin has a molecular weight ranging from 0.912 to 0.928 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 density.

15. The process according to any one of claims 1 to 14, characterized in that The linear low density polyethylene resin has a Mw / Mn ranging from 3.5 to 6.0 when measured by gel permeation chromatography.

16. The process according to any one of claims 1 to 15, characterized in that The linear low density polyethylene resin has a z-average molecular weight (Mz) ranging from 180,000 to 280,000 g / mol when measured by gel permeation chromatography.

17. The process according to any one of claims 1 to 16, characterized in that The linear low density polyethylene resin has a Mw of up to 110,000 g / mol when measured by gel permeation chromatography.

18. The process according to any one of claims 1 to 17, characterized in that The linear low density polyethylene resin is metallocene catalyzed; and / or has a bimodal molecular weight distribution.

19. The process according to any one of claims 1 to 18, characterized in that The high density polyethylene resin has an MI2 ranging from 0.6 to 1.5 g / 10 min when measured at 190° C. under a load of 2.16 kg according to ISO 1133-2005.

20. The process according to any one of claims 1 to 19, characterized in that The high density polyethylene resin has a molecular weight ranging from 0.952 to 0.964 g / cm2 when measured at 23°C according to ISO 1183-1:2012. 3 density.

21. A polyethylene composition, characterized in that It is produced by a process according to any one of claims 1 to 20.

22. A polyethylene composition, characterized in that It has: - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg; - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density; - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography; - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography; - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt% based on the total weight of the polyethylene composition as determined by C-NMR analysis.

23. The polyethylene composition according to claim 22, characterized in that It has: - an MI2 ranging from 1.0 to 2.6 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg; and / or - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.920 to 0.935 g / cm 3 density; and / or - When passing 13 A comonomer content ranging from 4.9 to 8.5 wt. %, based on the total weight of the polyethylene composition, as determined by C-NMR analysis; and / or - A main melting temperature peak, Tm, of at least 120°C when measured according to ISO 11357-3:2018.

24. The polyethylene composition according to claim 22 or 23, characterized in that It has: - a Mw / Mn in the range of from 3.2 to 5.8 when determined by gel permeation chromatography; and / or - a Mz / Mw range of from 2.0 to 5.0 when measured by gel permeation chromatography; and / or - a z-average molecular weight (Mz) of up to 350,000 g / mol when determined by gel permeation chromatography.

25. A film, which is a single-layer film or a multi-layer film, characterized in that One or at least one of the layers is made of the polyethylene composition according to any one of claims 11 to 24; and the film is a biaxially oriented polyethylene film or a monooriented polyethylene film.

26. A process for producing a biaxially oriented polyethylene film, characterized in that It includes: a) producing a polyethylene composition having: - MI2 ranging from 0.9 to 3.0 g / 10 min when measured according to ISO 1133-2005 at 190°C under a load of 2.16 kg; - When measured according to ISO 1183-1:2012 at 23°C, the range is from 0.915 to 0.935 g / cm 3 density; - a Mw / Mn ranging from 3.0 to 6.0 when determined by gel permeation chromatography; - a z-average molecular weight (Mz) of up to 370,000 g / mol when determined by gel permeation chromatography; - In the TREF curve, a major elution peak below 85°C and a minor elution peak above 95°C; and - When passing 13 The comonomer content ranges from 4.2 to 9.1 wt % based on the total weight of the polyethylene composition when measured by C-NMR analysis. b) extruding or casting a film comprising the polyethylene composition c) stretching the film in the machine direction and in the transverse direction to produce a biaxially oriented polyethylene film, wherein the stretch ratio in the machine direction is from 4.5 to 7.0 and the stretch ratio in the transverse direction is in the range of from 6.0 to 10.0; preferably, the stretch ratio in the machine direction is from 5.0 to 6.0 and / or the stretch ratio in the transverse direction is in the range of from 7.5 to 9.5.

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