Uniaxially oriented polyethylene film

Abstract

The present disclosure relates to a uniaxially oriented polyethylene film comprising a polymer blend (I) consisting of: A) from 55% to less than 75% by weight of a first polyethylene component having a density in the range of from 0.948 to 0.960 g / cm3, a melt index MIF in the range of from 35 to 100 g / 10 min, and a melt flow ratio MIF / MIP in the range of from 15 to 30; and B) from greater than 25% to 45% by weight of a second polyethylene component having a density from 0.949 to 0.965 g / cm3 and a melt index MIF from 5 to 30 g / 10 min.

Description

Technical Field

[0001] This disclosure relates to a uniaxially oriented polyethylene film with an unusual balance of special optical and mechanical properties. Background Technology

[0002] Polymer films are widely used in industrial manufacturing processes and non-industrial sectors for delivering goods to consumer markets in both wholesale and retail formats.

[0003] Currently, films composed of vinyl thermoplastic polymers dominate certain market applications, such as the market for household disposable products, garbage bags, and inner lining bags; outer packaging films and bags for laundry and dry cleaning items; and transport and takeaway bags for retail sales of non-perishable goods. In other aspects of the consumer goods delivery market, vinyl polymer films are only marginally competitive (if any) with other more expensive polymer films, such as plasticized PVC films and / or polypropylene films, such as in the heat shrink packaging film market for contour-fitting packaging of various items (especially perishable items such as cuts of meat, poultry, and fish). However, for other applications, such as packaging structures for agricultural products and grains, dry foods, and snacks, vinyl polymer films are competitive in certain cases.

[0004] Due to their valuable mechanical and optical properties, the demand for oriented polymer films in packaging applications is increasing.

[0005] WO9722470 discloses examples of oriented polyethylene films.

[0006] However, to achieve the optimal combination of performance, oriented polymer films (including uniaxial oriented films) typically have a multilayer structure, containing layers of different polymer materials such as polypropylene, polyethylene, polyethylene terephthalate, polyamide, and ethylene polyvinyl alcohol.

[0007] Such complex structures require complex processing in membrane fabrication and are difficult to meet current sustainability and recyclability requirements.

[0008] Polyethylene, particularly high-density polyethylene (HDPE), is an attractive candidate material for the preparation of uniaxially oriented films with reduced complexity in composition and structure.

[0009] In fact, HDPE can achieve high mechanical properties because it can be oriented up to a relatively high draw ratio.

[0010] Furthermore, with proper processing, HDPE can acquire valuable optical properties.

[0011] However, due to processing difficulties, the application of HDPE in the preparation of oriented films is severely limited, often resulting in insufficient final performance.

[0012] The purpose of this disclosure is to provide a uniaxially oriented polyethylene film that at least partially overcomes the deficiencies of the prior art, while being simple and inexpensive to produce. Summary of the Invention

[0013] Therefore, this disclosure provides a uniaxially oriented polyethylene film comprising a polymer blend (I) consisting of the following:

[0014] A) 55% to less than 75% by weight, preferably 55% to 74% by weight, more preferably 60% to 73% by weight, of a first polyethylene component having a density of 0.948 to 0.960 g / cm³. ³ The melt flow index (MIF) is 35 to 100 g / 10 min, and the melt flow ratio (MIF / MIP) is 15 to 30 (specifically, up to 25); and

[0015] B) A second polyethylene component comprising more than 25% to 45% by weight, preferably 26% to 45% by weight, and more preferably 27% to 40% by weight, wherein the density of the second polyethylene component is 0.949 to 0.965 g / cm³. ³ And the melt flow index (MIF) is 5 to 30 g / 10 min;

[0016] The weight percentages of the first polyethylene component and the second polyethylene component are relative to the total weight of the first polyethylene component and the second polyethylene component.

[0017] The uniaxially oriented polyethylene film unexpectedly possesses excellent mechanical properties (especially tensile modulus, tensile strength and elongation at break) and optical properties (especially haze and gloss). Detailed Implementation

[0018] A specific and preferred embodiment of the uniaxially oriented polyethylene film is a longitudinally oriented (MDO) polyethylene film, which is prepared by longitudinally oriented a primary film comprising the above-described polymer blend (I), as explained below.

[0019] In this paper: MIF represents the melt flow index measured at 190°C and 21.6 kg load; MIP represents the melt flow index measured at 190°C and 5 kg load; MIE represents the melt flow index measured at 190°C and 2.16 kg.

[0020] The first polyethylene component A) and the second polyethylene component B) can be selected from ethylene homopolymers and ethylene copolymers, and mixtures thereof, containing α-olefin monomer units (preferably, in amounts up to 10% by weight). Examples of the α-olefin monomer units are monomer units having 3 to 8 carbon atoms, particularly propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene. 1-Butene and 1-hexene are preferred.

[0021] The homopolymers and copolymers can be obtained by polymerization processes in the presence of a coordination catalyst. These processes and the homopolymers and copolymers obtained therefrom are extensively described in the art.

[0022] In particular, polymerization processes can be carried out in the presence of Ziegler-Natta catalysts or single-point catalysts.

[0023] As is well known, Ziegler-Natta catalysts comprise reaction products of organometallic compounds from Groups 1, 2, or 13 of the periodic table with transition metal compounds from Groups 4 to 10 (new numbering system) of the periodic table. Specifically, the transition metal compound can be selected from compounds of Ti, V, Zr, Cr, and Hf, and is preferably supported on MgCl2.

[0024] Particularly preferred catalysts include reaction products of organometallic compounds of Group 1, Group 2 or Group 13 of the periodic table and solid catalyst components including Ti compounds supported on MgCl2.

[0025] The preferred organometallic compound is an organoaluminum compound.

[0026] Single-point catalysts are well known in the art and are typically selected from metallocene single-point catalysts and non-metallocene single-point catalysts.

[0027] Examples of metallocene single-point catalysts are zirconium and hafnium, such as cyclopentadienyl or indene complexes of zirconium or hafnium, like bis(cyclopentadienyl)zirconium dichloride; bis(indene)zirconium dichloride or bis(indene)hafnium dichloride.

[0028] An example of a nonmetallocene single-site catalyst is an iron complex preferably having a tripentate ligand.

[0029] Particularly suitable tridentate ligands are 2,6-bis[1-(phenylimino)ethyl]pyridine, and preferably the corresponding compounds in which both phenyl groups are substituted at the ortho position with halogen or tertiary alkyl substituents.

[0030] Specific examples are 2,6-bis[1-(2-tert-butylphenylimino)ethyl]pyridine iron(II) dichloride; 2,6-bis[1-(2-tert-butyl-6-chlorophenylimino)ethyl]pyridine iron(II) dichloride or 2,6-bis[1-(2,4-dichlorophenylimino)ethyl]pyridine iron(II) dichloride.

[0031] The metallocene single-site catalyst and the non-metallocene single-site catalyst can also be used in combination.

[0032] Preferably, the unit-point catalyst reacts with an activating compound (co-catalyst), a preferred example of which is an aluminum oxane, such as monomethylaluminoxane (MAO).

[0033] The polymerization reaction can be continuous or intermittent, carried out in the presence of the catalyst, according to known techniques, and in the liquid phase, in the presence or absence of an inert diluent, or in the gas phase or by liquid-gas mixing techniques.

[0034] Reaction time, pressure, and temperature are not critical compared to the polymerization step; however, a temperature of 50 to 100°C is optimal. Pressure can be atmospheric pressure or higher.

[0035] Molecular weight adjustment is achieved by using known modifiers, particularly hydrogen.

[0036] Typically, the term "copolymer" is intended to also include polymers containing more than one comonomer, such as terpolymers.

[0037] All of the ethylene homopolymers and copolymers described herein are commercially available. Specific commercial polymers suitable for producing this polymer blend (I) are described in the examples.

[0038] Advantageously, but not necessarily, the tensile modulus of the first polyethylene component on the compression-molded sheet is at least 650 MPa (particularly, at least 800 MPa; more particularly, at least 850 MPa). According to some non-limiting embodiments, the tensile modulus of the first polyethylene component on the compression-molded sheet is at most 1300 MPa (particularly, at most 1200 MPa; more particularly, at most 1100 MPa).

[0039] Advantageously, but not necessarily, the tensile modulus of the second polyethylene component on the compression-molded sheet is up to 2000 MPa (more specifically, up to 1800 MPa).

[0040] According to some non-limiting embodiments, the tensile modulus of the second polyethylene component on the compression molding sheet is at least 500 MPa (specifically, at least 600 MPa; more specifically, at least 800 MPa).

[0041] Advantageously, but not necessarily, the weight-average molecular weight Mw of the second polyethylene component is equal to or less than 170,000 g / mol (in particular, equal to or less than 160,000 g / mol).

[0042] In some non-limiting cases, the Mw of the second polyethylene component is equal to or greater than 90,000 g / mol (in particular, equal to or greater than 100,000 g / mol).

[0043] According to a particularly preferred but non-limiting embodiment, the Mw / Mn ratio of the second polyethylene component is equal to or less than 18.0 (specifically, equal to or less than 15.0).

[0044] In some non-limiting cases, the Mw / Mn ratio of the second polyethylene component is equal to or greater than 5.0 (in particular, equal to or greater than 6.0).

[0045] According to some non-limiting embodiments, the number average molecular weight Mn of the second polyethylene component is equal to or greater than 9000 g / mol (particularly equal to or greater than 10000 g / mol); particularly, equal to or less than 25000 g / mol (more particularly, equal to or less than 22000 g / mol).

[0046] According to some non-limiting embodiments, the Z-average molecular weight Mz of the second polyethylene component is less than 800,000 g / mol (particularly equal to or less than 750,000 g / mol); particularly, equal to or greater than 200,000 g / mol (more particularly, equal to or greater than 250,000 g / mol).

[0047] Advantageously, but not necessarily, the weight-average molecular weight Mw of the first polyethylene component is equal to or greater than 175,000 g / mol (in particular, equal to or greater than 185,000 g / mol).

[0048] In some non-limiting cases, the Mw of the first polyethylene component is equal to or less than 250,000 g / mol (specifically, equal to or less than 210,000 g / mol).

[0049] Advantageously but not necessarily, the Mw / Mn ratio of the first polyethylene component is equal to or greater than 20.0 (in particular, equal to or greater than 22.0; more particularly, equal to or greater than 24.0).

[0050] In some non-limiting cases, the Mw / Mn ratio of the first polyethylene component is equal to or less than 35 (in particular, equal to or less than 30).

[0051] According to some non-limiting embodiments, the Z-average molecular weight Mz of the first polyethylene component is equal to or greater than 800,000 g / mol (particularly equal to or greater than 900,000 g / mol); particularly equal to or less than 150,000 g / mol (more particularly equal to or less than 120,000 g / mol).

[0052] According to some non-limiting embodiments, the number average molecular weight Mn of the first polyethylene component is equal to or less than 9000 g / mol (particularly equal to or less than 8000 g / mol); particularly equal to or greater than 4000 g / mol (more particularly equal to or greater than 6000 g / mol).

[0053] In all cases, Mw, Mn, and Mz were determined by gel permeation chromatography (GPC).

[0054] Experiments have shown that when the second polyethylene component has relatively low Mw (and / or Mz) and / or Mw / Mn (as described above), bidirectional oriented polymer films with particularly excellent optical and mechanical properties can be obtained.

[0055] Advantageously, but not necessarily, the density of the first polyethylene component is 0.950 to 0.960 g / cm³. ³ .

[0056] Advantageously, but not necessarily, the melt index (MIF) of the first polyethylene component is 40 to 80 g / 10 min, more preferably 45 to 80 g / 10 min.

[0057] Advantageously, but not necessarily, the melt index (MIP) of the first polyethylene component is 1.2 to 6.0 g / 10 min.

[0058] Advantageously, but not necessarily, the melt index (MIF) of the second polyethylene component is 5 to 28 g / 10 min, more preferably 10 to 25 g / 10 min.

[0059] Alternatively or additionally, the melt index (MIE) of the second polyethylene component is 0.1 to 3 g / min, more preferably 0.5 to 2 g / 10min.

[0060] Advantageously, but not necessarily, the melt flow ratio (MIF / MIP) of the second polyethylene component is 5 to 14, more preferably 5 to 12.

[0061] This polymer blend (I) may also contain conventional additives.

[0062] Examples of these additives are heat stabilizers, antioxidants, UV absorbers, light stabilizers, metal deactivators, peroxide-degrading compounds, and basic co-stabilizers, typically added in amounts from 0.01% to 10% by weight of the total weight of the polymer blend, preferably from 0.1% to 5% by weight (I).

[0063] The polymer blend (I) of the present invention can be obtained by a process including a combination step, during which a first polyethylene component and a second polyethylene component are combined by melting and mixing components, and the mixing is carried out in a mixing apparatus at a temperature typically between 160 and 250°.

[0064] Any known device and technique can be used for this purpose.

[0065] The melt mixing apparatus useful in this paper is, in particular, an extruder or kneader, with a twin-screw extruder being especially preferred. These components can also be premixed at room temperature in the mixing apparatus.

[0066] The uniaxially oriented polyethylene film of the present invention may be a single layer or multiple layers, wherein at least one layer comprises the polymer blend (I) of the present invention.

[0067] Because it is uniaxially oriented, the membrane is stretched (only) in one direction.

[0068] Preferably, the membrane is a longitudinally oriented (MDO) membrane, and therefore it is stretched in the longitudinal direction.

[0069] The "longitudinal direction" refers to the direction of travel of the film during extrusion.

[0070] In particular, the preferred stretch ratio of the uniaxially oriented polyethylene film of the present invention is 3:1 to 8:1.

[0071] Preferably, the thickness of the uniaxially oriented polyethylene film is equal to or less than 250 μm (specifically, equal to or less than 210 μm).

[0072] In all cases, the preferred lower limit for thickness is 10 μm.

[0073] In another embodiment, a method for producing the uniaxially oriented polyethylene film of the present invention is provided.

[0074] More precisely, but not necessarily, single-layer or multi-layer uniaxially oriented polyethylene films can be prepared using conventional processes in the existing technology.

[0075] The process includes a stretching step of a primary film comprising the polymer blend (I) of the present invention.

[0076] In some non-limiting cases, the thickness of the primary membrane before stretching is at least 0.3 mm (in particular, at least 0.5 mm).

[0077] Typically, the primary membrane is processed by being conveyed by a series of rollers with different rotational speeds.

[0078] Specifically, uniaxially oriented polyethylene films can be prepared using flat die extrusion and cooling roller cooling, or via annular die extrusion and air cooling of the resulting blown film. The resulting primary film is fed to a stretching device through rollers rotating at a speed higher than the extrusion rate to complete the stretching process. This orients the film along the longitudinal direction (MD).

[0079] The membrane extrusion is carried out using known techniques, preferably at a temperature of 180 to 300°C.

[0080] During the orientation stage in this stretching apparatus, the preferred main operating conditions are:

[0081] - Preheating temperature: 120 to 130°C;

[0082] - Warm-up time: 60 to 100 seconds;

[0083] -Tension speed: 15 to 40 mm / second;

[0084] -Stretch rate: 30% to 50% / second;

[0085] - Draw ratio: 3:1 to 8:1.

[0086] After stretching, the film is heat-set to maintain its orientation before being rolled up.

[0087] In all of the aforementioned processes, heating can be achieved by using, for example, an IR lamp or hot air or other heating elements (such as a resistance heater).

[0088] Orientation provides balanced mechanical properties. Membrane orientation significantly improves the tensile strength, flexibility, and toughness of the membrane. Orientation also enables the membrane to be used in heat-shrinkable applications.

[0089] Preferably, the uniaxially oriented polyethylene film of the present invention has one or more of the following properties:

[0090] - Haze level is 2% to 20%, more preferably 3% to 15%;

[0091] - Gloss of the film (at 45°C): 45 to 100 Gu, more preferably 60 to 90 Gu;

[0092] - Tensile modulus MD: 700 to 2200 MPa, more preferably 900 to 2000 MPa;

[0093] - Fracture strength MD: 100 to 280 MPa;

[0094] - Elongation at break (MD): 30% to 150%, more preferably 40% to 120%.

[0095] Example

[0096] The practices and advantages of the various embodiments, compositions, and methods provided herein are disclosed in the following examples. These examples are merely illustrative and are not intended to limit the scope of the appended claims in any way.

[0097] The following analytical methods are used to characterize polymer compositions.

[0098] Melt Flow Index

[0099] The determination was performed at 190°C and under the specified load, according to ISO 1133-1 2012-03.

[0100] density

[0101] Determined by immersion method at 23°C according to ISO 1183-1:2012.

[0102] Tensile modulus, yield strength and breaking strength, as well as yield elongation and breaking elongation

[0103] Determined according to ISO 527-2:2012 (compression-formed sheet test) and ASTM D882-18 (membrane test).

[0104] gloss

[0105] Determined according to ASTM D-2457-13.

[0106] Haze

[0107] Determined according to ASTM D-1003-13.

[0108] Molecular weight distribution determination

[0109] The average values ​​of Mw, Mn, and Mz, and the resulting Mw / Mn ratio, were determined by high-temperature gel permeation chromatography using the methods described in ISO 16014-1, ISO 16014-2, and ISO 16014-4, published in 2003. Details according to the mentioned ISO standards are as follows: solvent 1,2,4-trichlorobenzene (TCB); apparatus and solution temperature 145°C; and a PolymerChar (Valencia, Paterna 46980, Spain IR-4 infrared detector) compatible with TCB as the concentration detector. A WATERS Alliance 2000 system was used, equipped with a pre-column SHODEX UT-G and separation columns SHODEX UT 806 M (3 columns) and SHODEX UT 807 (Showa Denko Europe GmbH, Konrad-Zuse-Platz 4, 81829 Muenchen, Germany) connected in tandem.

[0110] The solvent was vacuum distilled under nitrogen and stabilized with 0.025 wt% 2,6-di-tert-butyl-4-methylphenol. The flow rate used was 1 ml / min, the injection volume was 500 μl, and the polymer concentration was in the range of 0.01% < concentration < 0.05% w / w. Molecular weight calibration was established using monodisperse polystyrene (PS) standards in the range of 580 g / mol to 11,600,000 g / mol from Polymer Laboratories (now Agilent Technologies, Herrenberger Str. 130, 71034 Boeblingen, Germany), with hexadecane also used.

[0111] The calibration curve was then adapted to polyethylene (PE) using a general calibration method (Benoit H., Rempp P., and Grubisic Z., *Journal of Polymer Science, Phys. Ed.*, 5, 753 (1967)). The Mark-Houwing parameters used here are as follows: for PS, k PS = 0.000121 dl / g, α PS = 0.706, and for PE, k PE = 0.000406 dl / g, α PE= 0.725, effective in TCB at 135℃. Data logging, calibration, and calculations were performed using NTGPC_Control_V6.02.03 and NTGPC_V6.4.24 (hs GmbH, Hauptstraße 36, D-55437 Ober-Hilbersheim, Germany), respectively.

[0112] Comonomer content

[0113] According to ASTM D 6248 98, the comonomer content was determined by IR using a Tensor 27 FT-IR spectrometer from Bruker. The Tensor 27 FT-IR spectrometer was calibrated with a stoichiometric model used to determine the ethyl side chain in PE (when 1-butene is used as a comonomer) and the butyl side chain in PE (when 1-hexene is used as a comonomer).

[0114] Example 1

[0115] This embodiment discloses the production of a sample of MDO polyethylene film and the properties of the obtained film.

[0116] The following commercially available starting materials sold by LyondellBasell Industries were used.

[0117] Component A): Hostalen GD 9555 (GD9555)

[0118] -MIP: 3.0 g / 10min;

[0119] -MIF: 63 g / 10min;

[0120] - Density: 0.953 g / cm³ 3 ;

[0121] -Tensive modulus: Compression-formed sheet: 1050 MPa;

[0122] - Yield tensile stress: Compression-formed plate: 25 MPa;

[0123] - Yield tensile strain: Compression-formed plate: 10%.

[0124] Component B): Luflexen hyPE 56P FA (hyPE)

[0125] -MIE: 0.77 g / 10min;

[0126] -MIF: 20.80 g / 10min;

[0127] -MIP: 2.18 g / 10min;

[0128] - Density: 0.955 g / cm³ 3 ;

[0129] -Tensive modulus: Compression-formed sheet: 1220 MPa;

[0130] The molecular weights are shown in Table 1 below.

[0131] Table 1

[0132]

[0133] Samples of MDO polyethylene films having the following polymer blends (I) were produced (percentages are by weight relative to the total weight of the polymer blends).

[0134] Example 1: 80% GD9555 + 30% hyPE;

[0135] Example 2: 80% GD9555 + 30% hyPE;

[0136] -Comparative Example 1: 100% GD9555;

[0137] - Comparative Example 2: 100% GD9555.

[0138] The following process was used to obtain the MDO membrane:

[0139] A primary membrane with a thickness of 1 mm was prepared using the Leonard production line with the following characteristics under the following conditions:

[0140] - Extruder diameter: 40 mm, L / D 27;

[0141] - Fixed displacement gear pump;

[0142] - Flat die, die lip width 200 mm, die lip gap 1 mm;

[0143] - Melting temperature: 240℃;

[0144] - 3 cooling rollers, 160 mm in diameter, roller temperature 45°C;

[0145] - Membrane cutting unit.

[0146] 93x93 mm specimens were cut from the primary membrane. These specimens were then oriented along the longitudinal direction (MD) using a Brueckner KARO IV tensile apparatus under the following conditions:

[0147] - Preheating temperature: 122°C;

[0148] Heating time: 80 seconds;

[0149] -Stretch speed: 28 mm / second;

[0150] -Stretch rate: 40% / second;

[0151] -Stretch area: 70x70mm (outside the fixture);

[0152] -Tension ratio: See Table 2;

[0153] - Final thickness: See Table 2.

[0154] The Brueckner KARO IV stretching equipment is used to reproduce the uniaxial stretching step, which is typically performed on an industrial scale by conveying the film via rollers.

[0155] The produced MDO polyethylene film has the properties shown in Table 2 below.

[0156] Table 2

[0157]

[0158] Table 2 (continued)

[0159]

[0160] As mentioned above, MD stands for "longitudinal direction". In other words, it means that the measurement is performed in the extrusion direction.

Claims

1. A uniaxially oriented polyethylene film, said uniaxially oriented polyethylene film comprising a polymer blend (I) consisting of the following: A) 55% to less than 75% by weight, preferably 55% to 74% by weight, more preferably 60% to 73% by weight of the first polyethylene component, wherein the density of the first polyethylene component is 0.948 to 0.960 g / cm³. ³ The melt flow index (MIF) is 35 to 100 g / 10 min, and the melt flow ratio (MIF / MIP) is 15 to 30 (specifically, up to 25); and B) A second polyethylene component comprising more than 25% to 45% by weight, preferably 26% to 45% by weight, and more preferably 27% to 40% by weight, wherein the density of the second polyethylene component is 0.949 to 0.965 g / cm³. ³ And the melt flow index (MIF) is 5 to 30 g / 10 min; The weight percentages of the first polyethylene component A) and the second polyethylene component B) are relative to the total weight of A) and B); MIF is the melt flow index measured according to ISO 1133-1 2012-03 at 190°C and 21.6 kg load; MIP is the melt flow index measured according to ISO 1133-1 2012-03 at 190°C and 5 kg load.

2. The uniaxially oriented polyethylene membrane according to claim 1, wherein the Mw / Mn ratio of the first polyethylene component A) is equal to or greater than 20.0, preferably equal to or greater than 22.0, more preferably equal to or greater than 24.0, wherein Mw is the weight-average molecular weight and Mn is the number-average molecular weight, both of which are determined by gel permeation chromatography (GPC).

3. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the Mw / Mn ratio of the second polyethylene component (B) is equal to or less than 18.0, preferably equal to or less than 15.

0.

4. The uniaxially oriented polyethylene membrane according to claim 1 or 2, wherein the Z-average molecular weight Mz of the first polyethylene component A) is equal to or greater than 800,000 g / mol, preferably equal to or greater than 900,000 g / mol, and the Z-average molecular weight Mz is determined by gel permeation chromatography (GPC).

5. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the Z-average molecular weight Mz of the second polyethylene component (B) is less than 800,000 g / mol, preferably equal to or less than 750,000 g / mol.

6. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the tensile modulus of the first polyethylene component A) on the compression molding plate is at least 650 MPa.

7. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the melt index (MIE) of the second polyethylene component (B) is 0.1 to 3 g / min, wherein the MIE is the melt index measured according to ISO 1133-1:2012-03 at 190°C and 2.16 kg load.

8. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the melt flow ratio (MIF / MIP) of the second polyethylene component (B) is 5 to 14, preferably 5 to 12.

9. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the thickness of the uniaxially oriented polyethylene film is equal to or less than 250 μm.

10. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the uniaxially oriented polyethylene film is a longitudinally oriented (MDO) film.

11. The uniaxially oriented polyethylene film according to claim 1 or 2, wherein the stretch ratio of the uniaxially oriented polyethylene film is 3:1 to 8:1, preferably stretched in the longitudinal direction (MD).

12. A method for producing a uniaxially oriented polyethylene film according to any one of the preceding claims, the method comprising a stretching step, during which a primary film comprising the polymer blend (I) is stretched in one direction, preferably in the longitudinal direction (MD).

13. The preparation method according to claim 12, wherein the thickness of the primary film is at least 0.3 mm.

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