Method for producing single-layer or multi-layer film, single-layer or multi-layer extruded film that is biaxially stretched simultaneously and heat-set, and corresponding use

Abstract

The invention relates to a single-layer or multi-layer, extruded, simultaneously biaxially stretched and heat-set film having a first polyethylene (PE1) having a thickness of greater than 0.940 g / cm3, which film can be used, for example, as a packaging material, in particular for food products, for example, as a packaging material for packaging food products. The invention also relates to a method for producing the film and to the use of the film, preferably for packaging food products.

Description

Technical Field

[0001] The present invention relates to a single-layer or multi-layer, extruded, biaxially stretched and heat-set film, a method for manufacturing the film, and the use of the film, preferably for packaging food, which can be used, for example, as a packaging material, especially for food packaging. Background Technology

[0002] In improving the reusability or recyclability of plastic-based packaging materials, the ideal approach is to use so-called single-material packaging, i.e., a pure material composed of only one type of plastic. However, in more demanding and complex applications, such as food packaging, the available materials often face technological limitations. Therefore, no single plastic can meet all the overall performance requirements for achieving ideal packaging performance. Typically, each plastic can only meet one or two of the following properties: barrier properties against water, water vapor, aromatic components, or gases such as oxygen; sufficient stiffness; puncture resistance; delamination resistance and other mechanical properties; good heat resistance; good sealing performance; and desirable optical properties such as low turbidity and good printability.

[0003] This sometimes results in complex multilayered structures with up to 13 layers and a large number of functional polymers, making the recycling of packaging materials made from them difficult or even impossible.

[0004] Therefore, to date, there is still a lack of solutions for plastic-based recyclable packaging materials, especially for food, that preferably fully meet all of the following requirements: stiffness, heat resistance, oxygen, gas and aroma barrier, and minimal to no shrinkage. Summary of the Invention

[0005] Therefore, an object of the present invention is to provide a method for manufacturing single-layer or multi-layer films and a single-layer or multi-layer, extruded, biaxially stretched and heat-set film that can be manufactured using this method, the film being suitable as a packaging material for food or being processable into suitable packaging materials and having improved recyclability. Another object is to provide corresponding uses.

[0006] Definition and measurement method of the present invention

[0007] "Extrusion": passing at least one type of molten thermoplastic material through a nozzle to form a thin film (a planar body with a small thickness of <3 mm) when the thermoplastic material exits the nozzle again, wherein the nozzle is preferably an annular or slit nozzle.

[0008] "After extrusion" means, within the technically feasible range, immediately following in time and / or space after the film exits the nozzle.

[0009] "Before stretching" refers to the time and / or space before forces are simultaneously applied to the film in the machine direction and in the transverse direction for the purpose of biaxial stretching.

[0010] "The point at which stretching begins" refers to the first point in time when forces along the machine direction and forces along the transverse direction are simultaneously applied to the film for the purpose of biaxial stretching.

[0011] "After stretching" means, within the technically feasible range for the purpose of biaxial stretching, immediately following the application of force simultaneously in the machine direction and in the transverse direction to the film at the end.

[0012] "Before heat setting" means in time and / or space before the film is heated to the temperature for heat setting (the third temperature (T3)).

[0013] Within the scope of this invention, “relaxation” can be understood as controlled shrinkage of the film along the machine direction (MD) and / or the transverse direction (TD). Controlled shrinkage along the MD can be achieved by varying the stretching speed, i.e., the downstream film stretching in the relaxation process operates or travels at a lower rotational speed than the upstream film stretching. Controlled shrinkage along the TD is achieved by reducing the film width between two film stretches. As is known to those skilled in the art, an example of a relaxation process for extruded and stretched single-layer or multi-layer films comes from Savic, Z., Savic. I, “Sausage Casings,” VICTUS Lebensmittelindustriebedarf Vertriebsgesellschaft mbH, Vienna, 1st edition, June 2002, Chapter 7, Section 4.2, pp. 267-270, particularly Figures 7-13a and 7-13b.

[0014] Density: Measured according to DIN ENISO 1183-1:2019-09

[0015] The temperature of the film (e.g. during stretching, heat setting, or relaxation): is the temperature of the film surface, preferably measured in a non-contact manner using an IR temperature sensor.

[0016] Shrinkage (or heat shrinkage): Measured in water at 90°C, preferably within 1 second of immersion, but at least within 10 seconds of immersion. According to the invention, to determine shrinkage (or heat shrinkage), the sample is immersed in water at 90°C for a predetermined, particularly as described above, duration, and immediately cooled to room temperature after removal. The length of the pre-marked segment after treatment is measured and correlated with the length of the same segment of the sample before treatment. The resulting length ratio (“shrinked” vs. “unshrinked”) defines the shrinkage. Depending on the direction of the length measurement, shrinkage is generated in the longitudinal direction (MD) and the transverse direction (TD). Total shrinkage is calculated by adding the shrinkage in the longitudinal direction and the shrinkage in the transverse direction. Multiple determinations of the length measurement, such as triple or quintuple determinations, and the resulting corresponding average values, advantageously improve the accuracy of the determination. According to the invention, shrinkage and total shrinkage can be determined, particularly according to ASTM D2732-14, 2020 edition, April 14, 2020.

[0017] Heat deflection temperature: This is the temperature at which the material is deformed, and it is measured according to ASTM D648-18.

[0018] Strength: Tensile properties (DIN EN ISO 527-1:2019-12, 2019-12 edition, and DIN EN ISO 527-2:2012-06, 2012-06 edition), flexural properties (3-point method) (ASTM D0790-17, July 24, 2017 edition), or flexural properties (4-point method) (ASTM D6272-17el, July 14, 2020 edition).

[0019] Stiffness: Measured according to DIN ENISO 527-1:2019-12, 2019-12 edition and DIN ENISO 527-2:2012-06, 2012-06 edition.

[0020] Transparency / turbidity / clarity: Measured according to ASTM D1003-21; June 7, 2021.

[0021] Printability: Measured according to DIN 16500-2:2018-09, 2018-09 edition, or defined as polarity in the form of surface tension, in units of Dyn / cm (=10 -3 (N / m) indicates the number of meters.

[0022] Sealing performance: e.g., the sealing / welding performance of the membrane / thermal tack test of the membrane: measured according to DIN 55571-2:2021-07.

[0023] Sealing joint strength: Measured according to DIN 55529:2012-09.

[0024] Sealing temperature: This refers to the temperature of the material to be sealed during the sealing process, measured as the temperature of the film, as previously defined.

[0025] Sealing / heat sealing: This involves attaching a thermoplastic coating to a carrier or to pure thermoplastic plastic under the influence of time, pressure, and temperature, while the carrier does not melt.

[0026] Within the scope of this invention, the following length definitions apply (each relating to the machine orientation or lateral direction):

[0027] L0: = The length of a predetermined section of the film before stretching;

[0028] L1: = The length of the same segment of the film after stretching and before relaxation;

[0029] L2: = The length of the same segment of the film after stretching and after relaxation.

[0030] Tensile Factor: Tensile factor V = the length L1 of a predetermined segment of the film after stretching and before relaxation, divided by the length L0 of the same segment of the film before stretching; (V = L1 / L0). According to the present invention, the tensile factor V, determined by the lengths L0 and L1 along the machine direction MD, is also referred to as the tensile factor V. MD According to the present invention, the tensile coefficient V, which is determined by the lengths L0 and L1 of TD in the transverse direction, is also referred to as the tensile coefficient V. TD .

[0031] Relaxation coefficient: Relaxation coefficient R = 1 - (the length L2 of a predetermined segment of the film after stretching and after relaxation divided by the length L1 of the same segment of the film after stretching and before relaxation); (R = 1 - (L2 / L1)). According to the present invention, the relaxation coefficient R calculated as described above and determined by the lengths L2 and L1 along the machine direction MD is also referred to as the relaxation coefficient R along the machine direction MD. MD According to the present invention, the relaxation coefficient R calculated as described above and used to determine lengths L2 and L1 along the transverse direction TD is also referred to as the relaxation coefficient R along the transverse direction TD. TD .

[0032] After performing the stretching and heat-setting steps, residual elongation or residual stretching occurs in the film following relaxation. Here, the residual stretching factor RV can be determined, which is defined in detail below, and is based on the ratio of the length L2 of a segment of the film after stretching, heat-setting, and relaxation to the length L0 of the same segment of the film before stretching and relaxation.

[0033] Residual tensile coefficient: Residual tensile coefficient RV = the length L2 of a predetermined segment of the film after stretching and relaxation, divided by the length L0 of the same segment of the film before stretching and relaxation; RV = L2 / L0. According to the present invention, the residual tensile coefficient RV, determined by the lengths L2 and L0 along the machine direction MD, is also referred to as the residual tensile coefficient RV. MD According to the present invention, the residual tensile coefficient RV, determined by the lengths L2 and L0 of TD in the transverse direction, is also referred to as the residual tensile coefficient RV. TD .

[0034] "Simultaneously biaxially stretched film": refers to a film that is stretched simultaneously not only in the machine direction but also in the transverse direction.

[0035] "Stable method" or "stable process": A method or process that allows for continuous operation (the execution of a method or process) and can produce thin films suitable for a specified application. "Unstable," correspondingly, means not "stable" in the above sense.

[0036] Further definitions, applicable within the scope of this invention and particularly to the subject matter and embodiments of the invention as defined in the claims and description, are set forth below. Here, in the sense of the invention, the numerical terms “first,” “second,” “third,” etc., used in the names of polymers, such as “second polyethylene” or “second polyethylene PE2,” represent only the name of the corresponding polymer as defined below and do not imply disclosure of any particular quantity or sequence of polymers. Thus, for example, according to the invention, stating “the film contains third polyethylene PE3” does not mean that the film also contains or must contain first polyethylene PE1 and second polyethylene PE2. More precisely, it simply means that the film contains third polyethylene PE3 as defined below, independently of other components, if any. Therefore, “third polyethylene” can also have any other name, such as “polyethylene C.” This applies accordingly to “first polyethylene,” “second polyethylene,” “first polypropylene,” “second polypropylene,” “third polypropylene,” “second polymer,” and “third polymer” as defined below. The following limitations, as defined, on the polymers mentioned also apply, regardless of whether the corresponding polymer is used with an indefinite or definite article in the description and / or claims.

[0037] Polyethylene (PE): A thermoplastic polymer that can be manufactured by chain polymerization of ethylene. Its repeating unit is [C2H4] (molecular formula) and its structural formula is:

[0038]

[0039] First type of polyethylene (PE1) (= High-density polyethylene (HDPE)): a type of polyethylene with a density greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density of the polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09. According to the invention, the first polyethylene (PE1) comprises one or more polymers of the polyethylene type (e.g., mixtures with different chain lengths). If the first polyethylene (PE1) consists of a mixture of multiple polymers of the polyethylene type, the aforementioned density range applies to the mixture after homogenization.

[0040] Secondary polyethylene (PE2): a material with a content of less than 0.940 g / cm³ 3 Preferred concentration is less than 0.920 g / cm³. 3 and greater than 0.870 g / cm 3 The density of the polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09, preferably a sealable polyethylene or a polyethylene suitable for forming a sealable layer. According to the invention, the second polyethylene (PE2) comprises one or more polymers of the polyethylene type (e.g., mixtures with different chain lengths). If the second polyethylene (PE2) consists of a mixture of multiple polymers of the polyethylene type, the aforementioned density range applies to the mixture after homogenization. The second polyethylene (PE2) is not the same as the first polyethylene (PE1).

[0041] Third polyethylene (PE3): A polyethylene (PE) having a density less than that of first polyethylene (PE1) and greater than that of second polyethylene (PE2), each of which is measured according to DIN EN ISO 1183-1:2019-09. According to the invention, third polyethylene (PE3) comprises one or more polymers of the polyethylene type (e.g., mixtures with different chain lengths). If third polyethylene (PE3) is composed of a mixture of multiple polymers of the polyethylene type, the aforementioned density range applies to the mixture after homogenization. Third polyethylene (PE3) is not the same as second polyethylene (PE2) and is not the same as first polyethylene (PE1).

[0042] Polypropylene (PP): A thermoplastic polymer that can be manufactured by chain polymerization of propylene. Its repeating unit is [C6H6] (molecular formula) and its structural formula is:

[0043]

[0044] First type of polypropylene (PP1): a polypropylene (PP) having a heat deflection temperature greater than 75°C, preferably greater than 85°C, and especially greater than 95°C, measured according to ASTM D648-18; and preferably greater than 0.895 g / cm³. 3 And less than 0.920 g / cm 3 Preferably greater than 0.899 g / cm³ 3 and less than 0.910 g / cm 3 The density is measured according to DIN EN ISO 1183-1:2019-09. According to the invention, the first polypropylene (PP1) comprises one or more polymers of the polypropylene type (e.g., mixtures with different chain lengths). If the first polypropylene (PP1) consists of a mixture of multiple polymers of the polypropylene type, the above range applies to the heat distortion temperature of the mixture after homogenization, and preferably also to the density of the mixture.

[0045] The second polypropylene (PP2) is a polypropylene (PP) having a heat deflection temperature of less than 75°C, preferably less than 65°C, and especially less than 55°C, as measured according to ASTM D648-18; preferably a sealable polypropylene or a polypropylene suitable for forming a sealable layer. According to the invention, the second polypropylene (PP2) comprises one or more polymers of the polypropylene type (e.g., mixtures with different chain lengths). If the second polypropylene (PP2) consists of a mixture of multiple polymers of the polypropylene type, the above range applies to the heat deflection temperature of the mixture after homogenization.

[0046] Third polypropylene (PP3): A polypropylene (PP) having a heat distortion temperature lower than that of first polypropylene (PP1) and higher than that of second polypropylene (PP2), each of which is measured according to ASTM D648-18. According to the present invention, third polypropylene (PP3) comprises one or more polymers of the polypropylene type (e.g., mixtures with different chain lengths). If third polypropylene (PP3) consists of a mixture of multiple polymers of the polypropylene type, the above ranges apply to the heat distortion temperatures of that mixture after homogenization.

[0047] The second polymer (PM2) is a polymer (preferably a polyolefin), which is preferably sealable, especially heat-sealable, and is preferably polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), or ethylene-methacrylic acid copolymer (EMA). When the second polymer (PM2) is a polyolefin, this is preferred, and according to the invention, it is referred to as the second polyolefin (PO2).

[0048] The third polymer (PM3) is a polymer (preferably a polyolefin) that is preferably non-sealable, even more preferably non-heat-sealable, particularly having a sealing temperature higher than that of the second polymer (PM2) (preferably the second polyolefin (PO2)), and preferably comprises polyethylene (PE) and / or polypropylene (PP) or any mixture thereof, or is composed of polyethylene (PE) and / or polypropylene (PP) or any mixture thereof. When the third polymer (PM3) is a polyolefin, this is preferred; according to the invention, it is referred to as the third polyolefin (PO3).

[0049] Polyethylene terephthalate (PET): Polyethylene terephthalate is obtained by polycondensation of terephthalic acid (1,4-phthalic acid) and ethylene glycol (1,2-dihydroxyethane).

[0050] Polyvinylidene chloride (PVDC): A thermoplastic similar to PVC, formed from dichloroethylene (1,1-dichloroethylene). PVDC decomposes near its melting point of approximately 200°C.

[0051] Polyamide (PA): is a substance selected from the group consisting of: PA composed of ε-caprolactam or poly(ε-caprolactam) (PA6), PA composed of hexamethylenediamine and adipic acid or polyhexamethylenediaminoamide (PA6.6), PA composed of ε-caprolactam and hexamethylenediamine / adipic acid (PA6.66), PA composed of hexamethylenediamine and dodecanoic acid or polyhexamethylenedodecanoamide (PA6.12), PA composed of 11-aminododecanoic acid or polydodecanoamide (PA11), PA composed of 12-laurolactam or poly(ω-laurolactam) (PA12), or mixtures of these PAs or mixtures of these PAs with amorphous PAs or with other polymers. Common spellings PAx.y are synonymous with PAx / y or PAxy.

[0052] Ethylene-vinyl alcohol copolymer (EVOH): is a fully saponifiable copolymer composed of ethylene and vinyl acetate, with repeating units of [C2H4O] and [C2H4] (molecular formula) and its structural formula is:

[0053]

[0054] Polyvinyl alcohol (PVOH): a polymer that can be produced by the complete saponification (hydrolysis) of polyvinyl acetate (PVAC). Its repeating unit is [C2H4O] (molecular formula) and its structural formula is:

[0055]

[0056] Tackifier (HV): This can be used as an intermediate layer and represents an adhesive layer in the film according to the invention, ensuring good composite adhesion between the individual layers. Here, HV is based on a raw material selected from the group consisting of PE, PP, ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-acrylic acid copolymer (EAA), and ionomers, or mixtures thereof. According to the invention, ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMA), or ethylene-methyl methacrylate copolymer (EMMA), each having a purity of >99%, preferably >99.9%, is particularly suitable as a tackifier. Unless defined above, those skilled in the art will understand that abbreviations used to denote general definitions common in the field of this invention are applicable.

[0057] In the context of this invention, referring to a material as a "layer component" means that a layer of a film according to the invention has at least partially that material. Here, in the context of this invention, the term "layer component" may specifically include a layer that is wholly or exclusively composed of that material.

[0058] In the context of this invention, "inner layer" refers to a layer of film that is the surface of the film facing or in contact with the article to be packaged, in accordance with the prescribed use of the film according to the invention as packaging material or as part of packaging material. Thus, the inner layer is the interface between the film and the article to be packaged when the film is used as packaging material, or, if another layer or layer of packaging is to be laminated onto the film according to the invention during further processing, it represents the interface between the film and another layer or layer of packaging.

[0059] In the context of this invention, "outer layer" refers to a layer of the film that constitutes the outward-facing surface of the film and does not directly contact the product to be packaged in the prescribed use of the film according to the invention as packaging material or as part of packaging material. Therefore, the outer layer is the interface between the film and the external environment. The outer and inner layers are two layers that enclose the film to the outside and are almost opposite each other.

[0060] In the context of this invention, an "intermediate" or "central" layer refers to a layer of the film disposed between the outer and inner layers of the film.

[0061] All mass fractions (in %), temperatures (in °C), and durations (in seconds) given within the scope of this application are precisely specified and determined to one decimal place (e.g., "50%" means "50.0%"; "120 °C" means "120.0 °C"; "2 seconds" means "2.0 seconds"; "1.5 seconds" means "1.5 seconds"), unless otherwise specified (e.g., "0.05 seconds" means "0.05 seconds").

[0062] Disclosure of the subject matter of the present invention

[0063] The above objectives are achieved by the subject matter defined in the claims and / or disclosed below.

[0064] The method according to the invention can be performed or implemented using a variety of methods and techniques known to those skilled in the art. In particular, this includes the so-called triple bubble method, the double bubble method with downstream thermoforming, and the tenter frame method with simultaneous, biaxial stretching. During heat setting, the film is guided through a furnace and subjected to temperature treatment, in most cases, as in the tenter frame method, by means of hot air. Alternatively, in the triple bubble method, heat setting of the film using infrared light or also using hot water steam is employed to reduce shrinkage caused during stretching. Alternatively, in the double bubble method, downstream heat setting can be performed using tempering rollers or a horizontal hot air furnace. Therefore, films according to the invention can be manufactured using these methods or other suitable methods and techniques known to those skilled in the art. This method and technique are known to those skilled in the art from relevant literature, such as Savic, Z., Savic. I's "Sausage Casings", ed. VICTUS Lebensmittelindustriebedarf Vertriebsgesellschaftm.bH, Vienna, 1st edition, June 2002, Chapter 7, especially Chapter 4.2, pp. 244-301, or from their practical experience.

[0065] In particular, the method and film according to the invention can preferably be performed or implemented using a double-bubble method and especially a triple-bubble method, for which the applicant provides suitable equipment. Here, the film can be, for example, produced by a blow molding head with a nozzle having a single layer or a composite film having two, three, or more layers, preferably by thermal separation of the layers, co-extruded from the corresponding resin melt, cooled by the applicant's water cooling, reheated, stretched simultaneously biaxially (in the machine direction (MD) and in the transverse direction (TD)) by means of closed compressed air bubbles, and finally heat-set within a defined temperature range in another step, and optionally relaxed in this case. Here, relaxation can be performed in both directions, i.e., not only in the machine direction (MD) but also in the transverse direction (TD). Crucially for the method according to the invention, relaxation is not performed in both directions (MD and TD) simultaneously, but the relaxation coefficient in the transverse direction TD is always greater than the relaxation coefficient in the machine direction MD. Furthermore, relaxation in only one direction, i.e., relaxation only in the TD, is also possible.

[0066] The choice of relaxation direction can always be made independently of each other. Within the scope of this invention, the quantitative expression of relaxation is represented by the so-called relaxation coefficient, which is defined in more detail below.

[0067] Another feasible method for manufacturing the film according to the invention is to stretch (co)extrude a flat film according to a strut frame method known to those skilled in the art.

[0068] The film of the present invention can be advantageously obtained by nozzle blow molding using the applicant's apparatus or equipment for manufacturing flexible food films, such as shrink films or shrink bags, for food packaging. In this case, the apparatus for rapidly cooling the thin thermoplastic tube after extrusion, disclosed in the same applicant's patent specification DE19916428B4, can be used additionally. For this purpose, a corresponding improvement according to patent specification DE10048178B4 can also be considered.

[0069] Here, a tubular film produced from the plastic melt in the blow molding head undergoes concentrated cooling, in which the amorphous structure of the thermoplastic from the plastic melt is preserved.

[0070] The tubular film, vertically extruded from the molten plastic in the blow molding head, initially migrates to a cooling device for cooling without wall contact, as detailed in documents DE19916428B4 and DE10048178B4. For details regarding the process, construction, and function of this cooling device, also known as a calibration device, please refer to the contents of documents DE19916428B4 and DE10048178B4 in their entirety to avoid repetition.

[0071] The tubular diaphragm then passes through supports in the cooling device. The diaphragm is supported against these supports due to the pressure difference between the inside of the tubular diaphragm and the coolant. A liquid film is retained between the diaphragm and the supports, thereby preventing adhesion of the tubular diaphragm. Here, the diameter of the supports affects the diameter of the tubular diaphragm; therefore, this cooling device from the same applicant is also referred to as a calibration device.

[0072] Using the method according to the invention, it is for the first time possible to manufacture single-layer or multi-layer films based on high-density polyethylene (HDPE) that meet the high requirements for packaging materials used in food. Crucially, according to the invention, the film is based on HDPE. The film according to the invention comprises HDPE (hereinafter referred to as "first polyethylene PE1" and its composition is as defined above as "first polyethylene PE1"). Within the scope of the invention, the first polyethylene PE1 has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³3 The density. In the film according to the invention, the mass fraction of the first polyethylene PE1 relative to the total mass of the film is greater than 30% to 100%.

[0073] The resulting film shrinks very little to no (0 to 3%, preferably 0 to 2%, especially 0 to 1%, shrinkage in the machine direction (MD) and transverse direction (TD), respectively, as measured at 90°C according to ASTM D2732-14, as described above). Here, the inventors have surprisingly discovered that empirically based manufacturing processes can only be stably operated when the stretch in the machine direction during simultaneous biaxial stretching is greater than the stretch in the transverse direction, and the resulting film exhibits satisfactory properties, particularly in its mechanical properties. This is a unique feature of the method according to the invention, because in simultaneous biaxial stretching, particularly in double-bubble and triple-bubble methods, the stretch in the machine direction is conventionally always set to be less than the stretch in the transverse direction.

[0074] Furthermore, the inventors have surprisingly discovered that, contrary to the expectations of any person skilled in the art, the following relationship applies in the method according to the invention: the greater the stretching of the film according to the invention at the stretching temperature set according to the invention, the less shrinkage occurs, and the lower the turbidity (greater clarity) and the more rigid the film becomes. Therefore, in the method according to the invention, small shrinkage or even complete elimination of such shrinkage can be achieved by selecting high stretching coefficients in both directions. However, according to the invention, the stretching coefficient in the machine direction must not exceed 8.0, preferably 7.5, and the stretching coefficient in the transverse direction must not exceed 7.0, preferably 6.5, because otherwise the stability of the film stretching process and therefore the stability of the film manufacturing process cannot be ensured.

[0075] The inventors have also discovered that the higher the density of the raw materials used, the higher the strength (hardness) and stiffness of the resulting film. Furthermore, the inventors have found that the higher the stretching (total stretch = the sum of stretching in both directions; or stretching only in the machine direction), the higher the strength and stiffness of the resulting film. This is because with increasing stretching, the crystallinity of the stretched polymer also increases, and therefore the arrangement of molecules in the polymer also increases. With the increase in molecular arrangement, the stiffness of the resulting film increases and its shrinkage decreases. During stretching, the temperature and duration of stretching also play a role: the higher the temperature the film is exposed to during stretching, and the longer the stretching continues at that temperature, the greater the crystallinity of the stretched polymer, and therefore the greater the stiffness of the stretched polymer.

[0076] Furthermore, the inventors have recognized that simultaneous biaxial stretching, achieved, for example, by known double-bubble and triple-bubble methods, offers a particular advantage associated with this invention: polymers with the highest densities, which achieve very high elongation coefficients due to their high density, can thus be processed. Due to the rapid cooling of the newly formed extruded hose, the polymer hose is maximally amorphous before stretching. Because of the simultaneous biaxial stretching—that is, stretching both along the machine direction and the transverse direction—the polymer material is maximally amorphous at the start of each stretch, thus allowing for stretching with a high elongation coefficient. In contrast, polymer materials subjected to uniaxial stretching via rollers or two-stage stretching using a tensioning frame method are already semi-crystalline or even crystalline after the first stretch, thus prohibiting the use of high-density polymer materials in these techniques, and making further stretching impossible, or only possible for materials with relatively low densities.

[0077] Therefore, according to the inventors' understanding, the triple bubble method using simultaneous biaxial stretching is ideal, more specifically because the amorphous state of the polymer is maximally preserved until stretching due to the rapid cooling of the newly formed polymer hose after co-extrusion. Due to the subsequent simultaneous stretching, the polymer material is thus maximally amorphous at the start of stretching in both directions (MD and TD). Even though it is theoretically impossible to achieve the high stretching coefficients of uniaxial stretching using rollers or the stretching frame method in the triple bubble method, it is the only method that allows the processing of the highest density polymer materials. Therefore, the triple bubble method allows for high stretching coefficients in both directions in high-density polymer materials, thereby ultimately achieving highly clear, very stable, and rigid films with minimal or no shrinkage. As the inventors have also discovered, the density of the processed polymer material is a more decisive factor than the achievable stretching coefficient; therefore, the triple bubble method in its current form achieves the best overall results compared to uniaxial stretching and stretching frame methods.

[0078] The inventors further understand that the longer the heat setting of the film (the dwell time during heat setting = the duration of setting at the setting temperature specified according to the invention) continues in the method according to the invention, the more transparent the resulting film becomes. It has also been observed that the higher the temperature during heat setting, the more transparent or less cloudy the resulting film becomes.

[0079] Furthermore, it is surprisingly found, within the scope of the improved method according to the invention, that the higher the temperature during heat setting, the clearer the resulting film and the higher its stiffness and mechanical stability. Also, the less relaxation during heat setting, the clearer and stiffer the resulting film. This is likely because the greater the stretching, the more crystalline and therefore more transparent the resulting film. This also accompanies less shrinkage of the film. If relaxation is completely omitted in the method according to the invention, the resulting film becomes even clearer in the sense of greater transparency.

[0080] In summary, the inventors of this invention have recognized that increasing the elongation coefficient during stretching, combined with an elongation coefficient greater along the machine direction than along the transverse direction, and higher temperatures and lower relaxation coefficients (or no relaxation) during heat setting, results in high transparency or clarity, high stiffness, and minimal shrinkage in the films obtained according to the invention. The inventors speculate that the reason for this surprising improvement in performance is the higher crystallinity of the main component of the film according to the invention, namely the first polyethylene PE1, compared to conventional methods or films. In the film according to the invention, the residual elongation coefficient (RV) along the transverse direction (TD) is... TD Preferably, the coefficient of thermal expansion is greater than 2.8 and less than 4.4, more preferably greater than 3.6 and less than 4.4, and particularly greater than 4.1 and less than 4.4. Furthermore, the residual tensile coefficient (RV) of the film along the machine direction (MD) is... MD Preferably, the content is greater than 3.6 and less than 5.4, more preferably greater than 4.1 and less than 5.4, and particularly greater than 5.0 and less than 5.4. When the film according to the invention contains a content greater than 0.960 g / cm³... 3 When the density of the first polyethylene PE1 is [not specified], for RV [not specified] TD and RV MD The above-mentioned range is particularly suitable. According to the invention, the content includes a value greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 In the case of a first polyethylene PE1 film with a certain density, the residual tensile coefficient (RV) of the film in the transverse direction (TD) is... TD Preferably, the content is greater than 4.0 and less than 6.0, more preferably greater than 4.5 and less than 6.0, and particularly greater than 5.0 and less than 6.0. Furthermore, it contains a content greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The residual tensile coefficient (RV) of the first polyethylene PE1 film along the machine direction (MD) of the density MDPreferably, the residual tensile coefficient (RV) is greater than 5.0 and less than 7.0, more preferably greater than 5.5 and less than 7.0, and particularly greater than 6.0 and less than 7.0. However, in any case, in the case of the film according to the invention, the residual tensile coefficient (RV) of the film along the machine direction (MD) is... MD Preferably, the residual tensile coefficient (RV) of the film is greater than that in the transverse direction (TD). TD ).

[0081] Furthermore, the inventors have surprisingly discovered the following correlations with the method according to the invention and the film according to the invention:

[0082] • The greater the corresponding stretching coefficient or stretching degree during biaxial stretching, the less shrinkage the resulting film will shrink.

[0083] • The greater the corresponding stretching coefficient or stretching degree during biaxial stretching, the lower the turbidity and the higher the clarity or transparency of the resulting film.

[0084] • The greater the corresponding stretching coefficient or stretching degree during biaxial stretching, the greater the stiffness of the resulting film.

[0085] • The higher the temperature during heat setting of the film, the higher the clarity or transparency and stability of the resulting film.

[0086] • The longer the heat setting of the film lasts, the higher the clarity or transparency and stability of the resulting film.

[0087] The smaller the relaxation coefficient during heat setting, the higher the clarity or transparency of the resulting film.

[0088] The smaller the relaxation coefficient during heat setting, the higher the stiffness of the resulting film.

[0089] The method according to the invention completely eliminates the need for lamination or extrusion coating of the film or individual layers or layers of packaging. On the one hand, this saves additional process steps, simplifying the implementation and equipment costs of the method according to the invention. On the other hand, the resulting film is mechanically more stable because the lamination interface of a laminated film always represents a mechanically weak point and increases the risk of delamination of one or more layers of the film. Since the film according to the invention is extruded or co-extruded in a single step, the resulting film can be up to 50% thinner than films made by separate extrusion of layers and subsequent lamination of the separately extruded layers, and having a thickness of, for example, 40 μm to 60 μm. This is also related to the fact that the method according to the invention allows the use of HDPE (=PE1) as a high-density layer component for producing the film according to the invention. In any case, the film according to the invention, with a thickness of, for example, 20 μm to 30 μm, up to 50% thinner, saves material and therefore energy compared to comparable films with similar layer structures made by lamination.

[0090] However, it is not excluded that the film according to the invention may be laminated with one or more other layers in a separate working step to form a spare film.

[0091] Another important aspect of the method according to the invention is that the film is cooled very rapidly to 20°C or lower after extrusion. Thus, the film's heat is almost immediately dissipated after it is formed by extrusion or co-extrusion, thereby preventing or at least avoiding the progression of polymer molecule crystallization. Therefore, it is equally important that the film is heated to the stretching temperature within seconds before stretching, and preferably stretched immediately after reaching the stretching temperature, i.e., with as little time delay as possible. Furthermore, in this respect, it is advantageous, but not necessarily necessary, that the film is cooled as quickly as possible to a temperature below 50°C after stretching.

[0092] By limiting the duration of the film's exposure to high temperatures, for example, before or during stretching, as provided by the invention, crystallization of HDPE (=PE1) is prevented as much as possible. Technically, this is ensured by extremely short heating and cooling times and minimizing the period during which the film is exposed to high temperatures, i.e., the time from the moment the stretching temperature is reached to the time after stretching begins. Therefore, the film according to the invention should be heated to the stretching temperature from the temperature to which the film is cooled after extrusion within a time period of 1 to 18 seconds, preferably 1.5 to 12 seconds, and especially 2 to 9 seconds. In other words, heating must be carried out over a distance of about 5 cm to 50 cm at the film's normal operating speed. According to the current state of development, such heating is technically impossible to achieve within a time period of less than 1 second. On the other hand, when the heating duration is too long, especially longer than 18 seconds, there is a risk that the crystallization of the polyolefin material begins or progresses too rapidly. To minimize the time the film is exposed to high temperatures and thus to a heat load that risks crystallization progression, the measure of immediately cooling the film after extrusion, as provided by the method according to the invention, is also used for this purpose.

[0093] In principle, it is important in the method according to the invention that the film does not crystallize or does not crystallize to a large extent before stretching. On the other hand, if the film crystallizes after stretching, this is in principle neither a problem nor even desirable, as it is advantageous. There may be a risk that air bubbles trapped in the film during stretching can cause the film to rupture and thus lead to an unstable process (particularly applicable to triple-bubble and double-bubble methods).

[0094] Therefore, in order to avoid crystallization of the polyolefin material in the film, the method according to the invention may also specify that the film be cooled very rapidly to a temperature below 50°C after stretching and before heat setting. Depending on the method technique used, this cooling step may be mandatory, for example in a triple bubble method or a double bubble method, or it may be optional, for example in a tenter frame method. Thus, the inventors have found that, for example, when manufacturing the film according to the invention using a triple bubble method, cooling the film to below 50°C after stretching, more preferably below 40°C, and even more preferably below 30°C, is crucial because otherwise the manufacturing process is unstable.

[0095] Furthermore, adhering to the temperature range set for heat setting according to the present invention is crucial. Therefore, the inventors have discovered that during the heat setting of a film, when the film temperature measured on the film surface is below 60°C, and according to the polymer material used, it is already below 100°C, the film becomes too cloudy and is therefore unusable for most intended applications, particularly as a food film. On the other hand, if the film temperature exceeds 200°C during heat setting, the film will suffer heat damage and may, for example, crack. On the other hand, the temperature windows set according to the present invention, particularly those greater than 60°C and less than 200°C, preferably greater than 80°C and less than 180°C, and especially greater than 100°C and less than 160°C, provide a very transparent film with good stability. When the first polyethylene PE1 contained in the film according to the present invention has a value greater than 0.960 g / cm³, the film becomes more transparent. 3 These temperature windows are particularly suitable when the density is [specific value]. The same temperature windows are also preferably suitable when the film according to the invention comprises a first polypropylene PP1 in the outer layer or when the outer layer is composed of a first polypropylene PP1.

[0096] On the other hand, if the first polyethylene PE1 contained in the film according to the invention has a content greater than 0.950 g / cm³, 3 And less than 0.960 g / cm 3 If the density is such that the film temperature measured on the surface of the film during heat setting is preferably greater than 80°C and less than 180°C, then the film temperature is preferably greater than 0.940 g / cm³. On the other hand, if the first polyethylene PE1 contained in the film according to the invention has a density greater than 0.940 g / cm³, then the film temperature is preferably greater than 0.940 g / cm³. 3 And less than 0.950 g / cm 3 If the density is such that the film temperature measured on the surface of the film during heat setting is preferably greater than 60°C and less than 160°C, then the film temperature is preferably greater than 60°C and less than 160°C.

[0097] A particular advantage of the film according to the invention is that it is recyclable. The film according to the invention is preferably planar or tubular.

[0098] In the films according to the invention, EVOH can be used as a layer component for good barrier properties against oxygen and other gases. Additionally or alternatively, within the scope of the invention, PVOH can also be provided as a layer component in the films according to the invention. As the inventors recognize, PVOH is more heat-sensitive and therefore can only be processed up to about 190°C and is also more expensive. However, PVOH provides better gas barrier properties than EVOH. Furthermore, PVOH can be well processed with polyethylene or polypropylene, and therefore can also be well bonded with the PE and PP materials processed in this application.

[0099] According to a preferred embodiment of the present invention, the inner layer of the film according to the present invention is a polyolefin sealing layer, which preferably comprises polyethylene (PE), especially a second polyethylene (PE2) or a third polyethylene (PE3), or is composed of polyethylene (PE), especially a second polyethylene (PE2) or a third polyethylene (PE3).

[0100] According to the present invention, preferably, one or more intermediate layers of the film according to the present invention comprise a polyolefin polymer, preferably polyethylene (PE), especially a third polyethylene (PE3), or are composed of a polyolefin polymer, preferably polyethylene (PE), especially a third polyethylene (PE3).

[0101] Alternatively, according to the invention, the film according to the invention may have an outer layer and an inner layer, the outer layer being composed of a first polypropylene PP1, and the inner layer being composed of a first polyethylene PE1, a second polyethylene PE2, or a third polyethylene PE3. With this construction, the heat resistance of the film is improved compared to, for example, a film composed solely of PE. This is because the first polypropylene PP1 has a higher melting temperature than PE (the melting temperature of PP1 is approximately 160°C to 165°C, while the melting temperature of PE is approximately 130°C to 135°C), thereby improving the overall heat resistance of the film while maintaining good sealing performance of the PE inner layer. Furthermore, this construction increases the melting temperature difference between the outer and inner layers compared to films where both the outer and inner layers are composed of polyethylene. This improves the processability of the entire film at higher temperatures, thereby enabling a higher number of cycles in the film production process.

[0102] According to the present invention, the film has an intermediate layer composed of a third polypropylene (PP3). By providing an intermediate layer composed of a third polypropylene (PP3), the stability of the film manufacturing process (process stability) is advantageously further improved, and the highest stability during manufacturing is achieved. Detailed Implementation

[0103] Preferred embodiments of the thin film according to the present invention

[0104] Below, some exemplary embodiments of the films according to the present invention are illustrated. These embodiments are suitable for both immediate use (“ready-to-use” or RTU) and for laminating additional layers. If only one material is specified for a layer, this means that the layer consists of that specified material. The corresponding layer structures are shown below (the layer sequence from left to right in the row refers to the outermost layer to the innermost layer):

[0105] • Single-layer film, composition: PE1

[0106] • Single-layer film, composition: >65% by mass of PE1 + <35% by mass of PE2 or PE3; for example, 75% by mass of PE1 + <25% by mass of PE2; or 70% by mass of PE1 + 20% by mass of PE2 + 10% by mass of PE3.

[0107] • Two-layer film: PE1 / / PE1

[0108] • Two-layer film: PE1 / / PE2

[0109] • Two-layer film: PE3 / / PE1

[0110] • 3-layer film: PE1 / / PE1 / / PE1

[0111] • 3-layer film: PE2 / / PE1 / / PE2

[0112] • 3-layer film: PE3 / / PE1 / / PE1

[0113] • 3-layer film: PE3 / / PE1 / / PE2

[0114] • 3-layer film: PE3 / / PE1 / / PE3

[0115] • 3-layer film: PP1 / / HV / / PE1

[0116] • 4-layer film: PE2 / / PE1 / / PE1 / / PE2

[0117] • 4-layer film: PE3 / / PE1 / / PE1 / / PE2

[0118] • 4-layer film: PE3 / / PE1 / / PE3 / / PE2

[0119] • 4-layer film: PE3 / / PE1 / / PE1 / / PE3

[0120] • 4-layer film: PP1 / / HV / / PE1 / / PE2

[0121] • 4-layer film: PP1 / / HV / / PE1 / / PE3

[0122] • 5-layer film: PE3 / / PE1 / / PE1 / / PE1 / / PE2

[0123] • 5-layer film: PE3 / / PE1 / / PE1 / / PE1 / / PE3

[0124] • 5-layer film: PE3 / / PE1 / / PE1 / / PE3 / / PE2

[0125] • 5-layer film: PE1 / / HV / / EVOH / / HV / / PE1

[0126] • 5-layer film: PP1 / / HV / / EVOH / / HV / / PE1

[0127] • 5-layer film: PE1 / / HV / / EVOH / / HV / / PE2

[0128] • 5-layer film: PE1 / / HV / / EVOH / / HV / / PE3

[0129] • 5-layer film: PE3 / / HV / / EVOH / / HV / / PE1

[0130] • 5-layer film: PE1 / / HV / / PVOH / / HV / / PE1

[0131] • 5-layer film: PP1 / / HV / / PVOH / / HV / / PE1

[0132] • 5-layer film: PE1 / / HV / / PVOH / / HV / / PE2

[0133] • 5-layer film: PE1 / / HV / / PVOH / / HV / / PE3

[0134] • 5-layer film: PE3 / / HV / / PVOH / / HV / / PE1

[0135] • 5-layer film: PP1 / / PP3 / / HV / / PE1 / / PE2

[0136] • 5-layer film: PP1 / / PP3 / / HV / / PE1 / / PE3

[0137] • 6-layer film: PE1 / / HV / / EVOH / / HV / / PE1 / / PE2

[0138] • 6-layer film: PP1 / / HV / / EVOH / / HV / / PE1 / / PE2

[0139] • 6-layer film: PE3 / / PE1 / / HV / / EVOH / / HV / / PE2

[0140] • 6-layer film: PE3 / / PE1 / / HV / / EVOH / / HV / / PE3

[0141] • 6-layer film: PE2 / / PE1 / / HV / / EVOH / / HV / / PE2

[0142] • 6-layer film: PE1 / / HV / / PVOH / / HV / / PE1 / / PE2

[0143] • 6-layer film: PP1 / / HV / / PVOH / / HV / / PE1 / / PE2

[0144] • 6-layer film: PE3 / / PE1 / / HV / / PVOH / / HV / / PE2

[0145] • 6-layer film: PE3 / / PE1 / / HV / / PVOH / / HV / / PE3

[0146] • 6-layer film: PE2 / / PE1 / / HV / / PVOH / / HV / / PE2

[0147] • 6-layer film: PP1 / / PP3 / / HV / / EVOH / / HV / / PE1

[0148] • 6-layer film: PP1 / / PP3 / / HV / / PVOH / / HV / / PE1

[0149] • 7-layer film: PE2 / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE2 • 7-layer film: PE3 / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE2 • 7-layer film: PE3 / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE3 • 7-layer film: PE2 / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE2 • 7-layer film: PE3 / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE2

[0150] • 7-layer film: PE3 / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE3

[0151] • 7-layer film: PP1 / / HV / / PE1 / / HV / / EVOH / / HV / / PE1

[0152] • 7-layer film: PP1 / / HV / / PE1 / / HV / / PVOH / / HV / / PE1

[0153] • 8-layer film: PE3 / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE3 / / PE2

[0154] • 8-layer film: PE3 / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE3 / / PE2

[0155] • 8-layer film: PP1 / / HV / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE2

[0156] • 8-layer film: PP1 / / HV / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE2

[0157] • 9-layer film: PE2 / / PE3 / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE3 / / PE2

[0158] • 9-layer film: PE2 / / PE3 / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE3 / / PE2

[0159] • 9-layer film: PP1 / / PP3 / / HV / / PE1 / / HV / / EVOH / / HV / / PE1 / / PE2

[0160] • 9-layer film: PP1 / / PP3 / / HV / / PE1 / / HV / / PVOH / / HV / / PE1 / / PE2

[0161] The above description and abbreviations of the preferred embodiments are as follows:

[0162] • " / / " indicates a layer boundary; for example, "A / / B / / C" indicates a multilayer film with three layers, wherein the outer layer is composed of component A, the middle layer is composed of component B, and the inner layer is composed of component C.

[0163] • The same reference numerals correspond to the same polymer components as in the claims;

[0164] • All illustrated embodiments can be manufactured using triple bubble technology according to the method of the present invention;

[0165] • All illustrated embodiments of the film according to the invention are limited to at least one of the product claims; in particular, all embodiments are extruded, biaxially stretched and heat-set films.

[0166] ·PE1 = the first polyethylene (PE1) as defined above (=HDPE);

[0167] • PE2 = the second type of polyethylene (PE2) as defined above, which is sealable;

[0168] • PE3 = the third polyethylene (PE3) as defined above;

[0169] •PP1 = the first polypropylene (PP1) as defined above;

[0170] • PP2 = the second type of polypropylene (PP2) as defined above, which is sealable;

[0171] • PP3 = the third type of polypropylene (PP3) as defined above;

[0172] • PM2 = the second polymer (PM2) as defined above, preferably the second polyolefin (PO2) as defined above, which is sealable;

[0173] • PM3 = the third polymer (PM3) as defined above, preferably the third polyolefin (PO3) as defined above;

[0174] • EVOH = ethylene-vinyl alcohol copolymer (EVOH) as defined above;

[0175] • PVOH = polyvinyl alcohol (PVOH) as defined above; and

[0176] • HV = Tackifier (HV) as defined above.

[0177] Preferred embodiments of the method according to the present invention are listed below:

[0178] Implementation Method 1 (V1)

[0179] (V1) A method for manufacturing a single-layer or multi-layer thin film, wherein the method comprises at least the following steps:

[0180] The step of extruding one or co-extruding multiple layers to obtain an extruded film;

[0181] The step of simultaneously biaxially stretching the extruded film; and

[0182] The step of heat setting the stretched film;

[0183] The film contains a first polyethylene (PE1) in a mass fraction of greater than 50%, preferably greater than 65%, preferably greater than 80%, and particularly preferably greater than 90% relative to the total mass of the film.

[0184] The first polyethylene (PE1) has a content greater than 0.950 g / cm³. 3 A particularly preferred ratio is greater than 0.960 g / cm³. 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 A particularly preferred ratio is less than 0.970 g / cm³. 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0185] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA);

[0186] The film is cooled to a first temperature (T1) below 20°C, particularly preferably below 15°C, within a time period of 0.05 to 0.5 seconds, particularly preferably 0.07 to 0.3 seconds after extrusion.

[0187] Wherein, the tensile coefficient (V) along the machine direction or longitudinal direction (MD) MD The value is greater than 5.0, preferably greater than 6.0, especially preferably greater than 7.0, and less than 8.0;

[0188] Wherein, the tensile coefficient (V) along the transverse direction (TD) TD The value is greater than 4.0, preferably greater than 5.0, especially preferably greater than 6.0, and less than 7.0;

[0189] Wherein, the tensile coefficient (V) along the machine direction (MD) MD The elongation factor (V) is greater than that along the transverse direction (TD). TD );

[0190] The film has a second temperature (T2) during the stretching process that is greater than 130°C and less than 170°C, and particularly preferably greater than 140°C and less than 160°C.

[0191] The film is heated from the first temperature (T1) to the second temperature (T2) within a time period of 1.0 second to 12 seconds, particularly preferably 2 seconds to 9 seconds, before stretching;

[0192] The duration (Δt) (=t2-tl) between the first time point (t1) when the film reaches the second temperature (T2) and the second time point (t2) when the film begins to stretch is 0.1 seconds to 3 seconds, and particularly preferably 0.3 seconds to 1.5 seconds;

[0193] The film, during the heat setting period, has a third temperature (T3) greater than 80°C and less than 180°C, particularly preferably greater than 100°C and less than 160°C; and

[0194] The dwell time during the heat setting period (= duration of heat setting of the film) is greater than 1 second and less than 45 seconds, particularly preferably greater than 3 seconds and less than 30 seconds, during which the film has the third temperature (T3).

[0195] Implementation Method 2 (V2)

[0196] (V2) The method according to (V1), wherein the method further specifies relaxing the film during the heat setting of the film;

[0197] Wherein, the relaxation coefficient (R) along the machine direction (MD) MD The value is greater than 0.00 and less than 0.10, preferably greater than 0.00 and less than 0.05, and particularly preferably greater than 0.00 and less than 0.03;

[0198] Wherein, the relaxation coefficient (R) along the lateral direction (TD) TD The value is greater than 0.00 and less than 0.20, preferably greater than 0.00 and less than 0.10, and particularly preferably greater than 0.00 and less than 0.05; and

[0199] Wherein, the relaxation coefficient (R) along the lateral direction (TD) TD The relaxation coefficient (R) is greater than that along the machine direction (MD). MD );

[0200] The thin film has the third temperature (T3) during the relaxation period; and

[0201] The relaxation duration of the film is preferably greater than 5 seconds, particularly preferably greater than 10 seconds, and less than 30 seconds, during which the film has the third temperature (T3).

[0202] Implementation Method 3 (V3)

[0203] (V3) The method according to (V1) or (V2), wherein the method further specifies cooling the film after stretching and before heat setting;

[0204] The film is cooled to a fourth temperature (T4) below 40°C, particularly preferably below 30°C, within a time period of 0.01 to 0.5 seconds, particularly preferably 0.07 to 0.3 seconds after stretching.

[0205] Implementation Method 4 (V4)

[0206] (V4) The method according to (V1), (V2) or (V3), wherein the film further comprises a first polypropylene (PP1); and wherein the first polypropylene (PP1) has a heat deflection temperature greater than 85°C, particularly preferably greater than 95°C, the heat deflection temperature being measured according to ASTM D648-18.

[0207] Implementation Method 5 (V5)

[0208] (V5) The method according to (V1), (V2), (V3) or (V4), wherein the thin film is multilayered;

[0209] The film contains ethylene-vinyl alcohol copolymer (EVOH) in a mass fraction of less than 5% relative to the total mass of the film;

[0210] The film has at least one layer, which is composed of ethylene-vinyl alcohol copolymer (EVOH).

[0211] Implementation Method 6 (V6)

[0212] (V6) The method according to (V1), (V2), (V3), (V4) or (V5), wherein the thin film is multilayered;

[0213] The film contains polyvinyl alcohol copolymer (PVOH) in a mass fraction of less than 5% relative to the total mass of the film;

[0214] The film has at least one layer composed of a polyvinyl alcohol copolymer (PVOH).

[0215] Implementation Method 7 (V7)

[0216] (V7) The method according to (V1), (V2), (V3), (V4), (V5) or (V6), wherein the thin film is multilayered;

[0217] The film has an outer layer composed of a second polyethylene (PE2).

[0218] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and

[0219] The outer layer does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH).

[0220] Implementation Method 8 (V8)

[0221] (V8) The method according to (V1), (V2), (V3), (V4), (V5), (V6) or (V7), wherein the thin film is multilayered;

[0222] The film has an inner layer composed of a second polyethylene (PE2).

[0223] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3The density, which is measured according to DIN EN ISO 1183-1:2019-09; and

[0224] The inner layer does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH).

[0225] Implementation Method 9 (V9)

[0226] (V9) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7) or (V8), wherein the thin film is multilayered;

[0227] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0228] The film has at least one layer, the layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH);

[0229] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2); and

[0230] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09.

[0231] Implementation Method 10 (V10)

[0232] (V10) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8) or (V9), wherein the thin film is multilayered;

[0233] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0234] The film has at least one layer, the layer comprising or composed of polyvinyl alcohol copolymer (PVOH);

[0235] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2); and

[0236] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09.

[0237] Implementation Method 11 (V11)

[0238] (V11) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9) or (V10), wherein the thin film is multilayered;

[0239] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0240] The film has at least one layer, the layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH);

[0241] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0242] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0243] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0244] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0245] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0246] Implementation Method 12 (V12)

[0247] (V12) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10) or (V11), wherein the thin film is multilayered;

[0248] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0249] The film has at least one layer, the layer comprising or composed of a polyvinyl alcohol copolymer (PVOH); and

[0250] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0251] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0252] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0253] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0254] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0255] Implementation Method 13 (V13)

[0256] (V13) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10), (V11) or (V12), wherein the thin film is multilayered;

[0257] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0258] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0259] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0260] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0261] Implementation Method 14 (V14)

[0262] (V14) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10), (V11), (V12) or (V13), wherein the thin film is multilayered;

[0263] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0264] The film has at least one layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3), wherein the third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2).

[0265] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2); and

[0266] Preferably, the film has at least one layer, the layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0267] Implementation Method 15 (V15)

[0268] (V15) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10), (V11), (V12), (V13) or (V14), wherein the thin film is multilayered;

[0269] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0270] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2), the second polyethylene (PE2) having a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density, which is measured according to DIN ENISO 1183-1:2019-09;

[0271] The film has at least one layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3), wherein the third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2).

[0272] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2); and

[0273] Preferably, the film has at least one layer, the layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0274] Implementation Method 16 (V16)

[0275] (V16) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10), (V11), (V12), (V13), (V14) or (V15), wherein the thin film is multilayered;

[0276] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0277] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0278] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0279] The film does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH);

[0280] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0281] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0282] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0283] Implementation Method 17 (V17)

[0284] (V17) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10), (V11), (V12), (V13), (V14), (V15) or (V16), wherein the thin film is multilayered;

[0285] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0286] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0287] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0288] The film does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH);

[0289] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0290] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0291] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0292] Implementation Method 18 (V18)

[0293] (V18) The method according to (V1), (V2), (V3), (V4), (V5), (V6), (V7), (V8), (V9), (V10), (V11), (V12), (V13), (V14), (V15), (V16) or (V17), wherein the method does not include the step of laminating or extruding a layer of the film or its components, particularly preferably a layer of the film; and / or

[0294] The film is multilayered, and the co-extrusion of the multilayered film is performed in a single step.

[0295] The following are preferred embodiments of the thin film according to the invention, which are preferably manufactured using the method according to the invention, especially any one of the aforementioned methods V1 to V18:

[0296] Implementation Method 1 (F1)

[0297] (F1) A single-layer or multi-layer, extruded, simultaneously biaxially stretched and heat-set film, preferably manufactured according to the method according to the invention or according to any one of embodiments (V1) to (V18).

[0298] The film comprises a first polyethylene (PE1);

[0299] The first polyethylene (PE1) has a content greater than 0.950 g / cm³. 3A particularly preferred ratio is greater than 0.960 g / cm³. 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 A particularly preferred ratio is less than 0.970 g / cm³. 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0300] The film comprises the first polyethylene (PE1) in a mass fraction of greater than 50%, preferably greater than 65%, preferably greater than 80%, and particularly preferably greater than 90% relative to the total mass of the film; and

[0301] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0302] Implementation Method 2 (F2)

[0303] (F2) The film according to (F1), wherein the film is not laminated.

[0304] Implementation Method 3 (F3)

[0305] (F3) The film according to (F1) or (F2), wherein the film is relaxed;

[0306] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 5.0 and less than 7.0, preferably greater than 5.5 and less than 7.0;

[0307] The residual tensile coefficient (RV) of the film in the transverse direction (TD) TD The value is greater than 4.0 and less than 6.0, preferably greater than 5.0 and less than 6.0; and

[0308] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0309] The thin film is relaxed;

[0310] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 7.0. TD() Greater than 4.0 and less than 6.0; and

[0311] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

[0312] Implementation Method 4 (F4)

[0313] (F4) The film according to (F1), (F2) or (F3), wherein the film comprises a first polypropylene (PP1); and

[0314] The first polypropylene (PP1) has a heat deflection temperature greater than 85°C, particularly preferably greater than 95°C, which is measured according to ASTM D648-18.

[0315] Implementation Method 5 (F5)

[0316] (F5) The film according to (F1), (F2), (F3) or (F4), wherein the film is multilayered;

[0317] The film contains an ethylene-vinyl alcohol copolymer (EVOH) at a mass fraction of less than 5% relative to the total mass of the film; and

[0318] The film has at least one layer, which is composed of ethylene-vinyl alcohol copolymer (EVOH).

[0319] Implementation Method 6 (F6)

[0320] (F6) The film according to (F1), (F2), (F3), (F4) or (F5), wherein the film is multilayered;

[0321] The film comprises polyvinyl alcohol copolymer (PVOH) in a mass fraction of less than 5% relative to the total mass of the film; and

[0322] The film has at least one layer composed of a polyvinyl alcohol copolymer (PVOH).

[0323] Implementation Method 7 (F7)

[0324] (F7) The thin film according to (F1), (F2), (F3), (F4), (F5) or (F6), wherein the thin film is multilayered;

[0325] The film has an outer layer composed of a second polyethylene (PE2).

[0326] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and

[0327] The outer layer does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH).

[0328] Implementation method 8 (F8)

[0329] (F8) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6) or (F7), wherein the thin film is multilayered;

[0330] The film has an inner layer, and the outer layer comprises or is composed of a second polyethylene (PE2).

[0331] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09; and

[0332] The inner layer does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH).

[0333] Implementation Method 9 (F9)

[0334] (F9) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7) or (F8), wherein the thin film is multilayered;

[0335] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0336] The film has at least one layer, which is composed of ethylene-vinyl alcohol copolymer (EVOH);

[0337] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0338] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09.

[0339] Implementation Method 10 (F10)

[0340] (F10) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8) or (F9), wherein the thin film is multilayered;

[0341] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0342] The film has at least one layer, which is composed of a polyvinyl alcohol copolymer (PVOH);

[0343] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2); and

[0344] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09.

[0345] Implementation Method 11 (F11)

[0346] (F11) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9) or (F10), wherein the thin film is multilayered;

[0347] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0348] The film has at least one layer, the layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH);

[0349] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0350] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0351] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0352] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0353] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0354] Implementation Method 12 (F12)

[0355] (F12) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9), (F10) or (F11), wherein the thin film is multilayered;

[0356] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0357] The film has at least one layer, the layer comprising or composed of a polyvinyl alcohol copolymer (PVOH); and

[0358] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0359] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0360] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0361] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0362] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0363] Implementation Method 13 (F13)

[0364] (F13) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9), (F10), (F11) or (F12), wherein the thin film is multilayered;

[0365] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0366] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0367] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0368] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0369] Implementation Method 14 (F14)

[0370] (F14) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9), (F10), (F11), (F12) or (F13), wherein the thin film is multilayered;

[0371] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0372] The film has at least one layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3), wherein the third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2).

[0373] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2); and

[0374] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0375] Implementation Method 15 (F15)

[0376] (F15) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9), (F10), (F11), (F12), (F13) or (F14), wherein the thin film is multilayered;

[0377] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0378] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2), the second polyethylene (PE2) having a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density, which is measured according to DIN ENISO 1183-1:2019-09;

[0379] The film has at least one layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3), wherein the third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2).

[0380] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2); and

[0381] Preferably, the film has at least one layer, the layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0382] Implementation Method 16 (F16)

[0383] (F16) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9), (F10), (F11), (F12), (F13), (F14) or (F15), wherein the thin film is multilayered;

[0384] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0385] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0386] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0387] The film does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH);

[0388] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0389] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0390] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0391] Implementation Method 17 (F17)

[0392] (F17) The thin film according to (F1), (F2), (F3), (F4), (F5), (F6), (F7), (F8), (F9), (F10), (F11), (F12), (F13), (F14), (F15) or (F16), wherein the thin film is multilayered;

[0393] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0394] The film has at least one layer, the layer comprising or composed of a second polyethylene (PE2);

[0395] The film has at least one layer, the layer comprising or composed of a third polyethylene (PE3) and / or a third polypropylene (PP3);

[0396] The film does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH);

[0397] The second polyethylene (PE2) has a content of less than 0.92 g / cm³. 3 And greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09;

[0398] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0399] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0400] Implementation method 18 (F18)

[0401] (F18) The film according to (F1), (F2) or (F3), wherein the film comprises a single layer, the single layer being composed of the first polyethylene (PE1); or

[0402] The film is composed of multiple, preferably two, three, four or five layers, each of which is composed of the first polyethylene (PE1).

[0403] The following are preferred embodiments according to the purpose of the invention:

[0404] Implementation Method 1 (U1)

[0405] (U1) First polyethylene (PE1) is used for single-layer or multi-layer, extruded, biaxially stretched and heat-set films, preferably for films according to the invention or films according to any one of embodiments (F1) to (F18), or for the manufacture of said films;

[0406] The film contains the first polyethylene (PE1) in a mass fraction of more than 50%, preferably more than 65%, more preferably more than 80%, and particularly preferably more than 90% of the total mass of the film.

[0407] The first polyethylene (PE1) has a content greater than 0.950 g / cm³. 3 A particularly preferred ratio is greater than 0.960 g / cm³. 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 A particularly preferred ratio is less than 0.970 g / cm³. 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and

[0408] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0409] Implementation Method 2 (U2)

[0410] (U2) According to the use described in (U1), wherein the film further comprises a first polypropylene (PP1) having a heat deflection temperature greater than 85°C, particularly preferably greater than 95°C, the heat deflection temperature being measured according to ASTM D648-18.

[0411] Implementation Method 3 (U3)

[0412] (U3) The film according to any one of embodiments (F1) to (F18) is used as a ready-to-use packaging material for food or for manufacturing a ready-to-use packaging material for food by laminating another polymer layer or a plurality of additional polymer layers or a package consisting of a plurality of polymer layers.

[0413] Any selection of features marked "especially" or "particularly preferred" in the claims or description is combined with each other in the sense of the overall particularly preferred embodiment of the invention, which is explicitly part of the disclosure of the invention.

[0414] Furthermore, any selection of features marked "preferred" in the claims or description is combined with each other in the sense of the overall preferred embodiment of the invention, which is explicitly part of the disclosure of the invention.

[0415] Furthermore, any selection of features marked "particularly preferred" in the foregoing or subsequent embodiments is combined with each other in the sense of the overall particularly preferred embodiment of the invention, which is explicitly part of the disclosure of the invention.

[0416] Furthermore, any selection of features marked "preferred" in the foregoing or subsequent embodiments is combined with each other in the sense of the overall preferred embodiment of the invention, which is explicitly part of the disclosure of the invention.

[0417] Further disclosure of the present invention

[0418] Within the scope of this invention, the terms "manufactured according to the method" and "can be manufactured according to the method" have the same meaning and can be used interchangeably.

[0419] The subject matter of an independent method claim may be limited by one of the following features or by any choice of the following features, including all of them:

[0420] • The film contains the first polyethylene (PE1) in a mass fraction of more than 50%, preferably more than 65%, preferably more than 80%, and especially more than 90% relative to the total mass of the film;

[0421] • Wherein, the dwell time during the heat setting period (= duration of the heat setting of the film) is greater than 1.5 seconds and less than 50 seconds, preferably greater than 2 seconds and less than 40 seconds, especially greater than 3 seconds and less than 30 seconds, and the film has the third temperature (T3) during the heat setting period.

[0422] The subject matter of an independent product claim can be further limited by the following features:

[0423] • The film contains the first polyethylene (PE1) in a mass fraction of more than 50%, preferably more than 65%, more preferably more than 80%, and especially more than 90% relative to the total mass of the film.

[0424] Within the scope of this invention, particularly in claim 2, the following features are defined:

[0425] • Wherein, the film is cooled to a first temperature (T1) below 20°C, preferably below 15°C, and especially below 10°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after extrusion;

[0426] It can be characterized by:

[0427] • Wherein, the film is cooled after extrusion at a cooling rate of 240°C / second to 24000°C / second, preferably 800°C / second to 3500°C / second;

[0428] To replace or supplement.

[0429] Within the scope of this invention, particularly in claim 2, the following features are defined:

[0430] •The film is heated from the first temperature (T1) to the second temperature (T2) within a time period of 1 to 18 seconds, preferably 1.5 to 12 seconds, and especially 2 to 9 seconds before stretching.

[0431] It can be characterized by:

[0432] •The film is heated from the first temperature (T1) to the second temperature (T2) at a heating rate of 5°C / second to 170°C / second, preferably 10°C / second to 85°C / second;

[0433] To replace or supplement.

[0434] Within the scope of this invention, particularly in claim 6, the following features are defined:

[0435] • Wherein, the film is cooled to a fourth temperature (T4) below 50°C, preferably below 40°C, and especially below 30°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after stretching;

[0436] It can be characterized by:

[0437] •The film is cooled to a fourth temperature (T4) below 50°C, preferably below 40°C, and especially below 30°C after stretching at a cooling rate of 100°C / second to 10000°C / second.

[0438] To replace or supplement.

[0439] Further disclosure of the present invention

[0440] The following numbers 1 to 59 define the subject matter that belongs to and is included in this invention:

[0441] 1. A method for manufacturing single-layer or multi-layer thin films, wherein the method comprises at least the following steps:

[0442] The step of extruding one or co-extruding multiple layers to obtain an extruded film;

[0443] Simultaneous biaxial stretching and extrusion of film; and

[0444] The step of heat setting the stretched film;

[0445] The film comprises a first polyethylene (PE1);

[0446] The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0447] The film contains the first polyethylene (PE1) in a mass fraction of more than 30%, preferably more than 40%, more than 50%, more than 65%, more than 80%, and especially more than 90% relative to the total mass of the film.

[0448] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA);

[0449] Wherein, the tensile coefficient (V) along the machine direction (MD) MD The elongation factor (V) is greater than that along the transverse direction (TD). TD );

[0450] The film, during the stretching process, has a second temperature (T2) greater than 120°C and less than 180°C, preferably greater than 130°C and less than 170°C, and particularly greater than 140°C and less than 160°C; and

[0451] The film has a third temperature (T3) during the heat setting process, which is greater than 60°C and less than 200°C, preferably greater than 80°C and less than 180°C, and especially greater than 100°C and less than 160°C.

[0452] 2. A method for manufacturing single-layer or multi-layer thin films, wherein the method comprises at least the following steps:

[0453] The step of extruding one or co-extruding multiple layers to obtain an extruded film;

[0454] The step of simultaneously biaxially stretching the extruded film; and

[0455] The step of heat setting the stretched film;

[0456] The film comprises a first polyethylene (PE1);

[0457] The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0458] The film contains the first polyethylene (PE1) in a mass fraction of more than 30%, preferably more than 40%, more than 50%, more than 65%, more than 80%, and especially more than 90% relative to the total mass of the film.

[0459] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA);

[0460] The film is cooled to a first temperature (T1) below 20°C, preferably below 15°C, and especially below 10°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after extrusion.

[0461] Wherein, the tensile coefficient (V) along the machine direction (MD) MD The elongation factor (V) is greater than that along the transverse direction (TD). TD );

[0462] The film has a second temperature (T2) during the stretching process that is greater than 120°C and less than 180°C, preferably greater than 130°C and less than 170°C, and especially greater than 140°C and less than 160°C.

[0463] The film is heated from the first temperature (T1) to the second temperature (T2) within a time period of 1 to 18 seconds, preferably 1.5 to 12 seconds, and especially 2 to 9 seconds before stretching.

[0464] The duration (Δt) (=t2-t1) between the first time point (t1) when the film reaches the second temperature (T2) and the second time point (t2) when the film begins to stretch is 0.05 seconds to 6 seconds, preferably 0.1 seconds to 3 seconds, and especially 0.3 seconds to 1.5 seconds;

[0465] The film, during the heat setting period, has a third temperature (T3) greater than 60°C and less than 200°C, preferably greater than 80°C and less than 180°C, and particularly greater than 100°C and less than 160°C; and

[0466] The dwell time during the heat setting period (= duration of heat setting of the film) is greater than 1 second and less than 60 seconds, preferably greater than 2 seconds and less than 45 seconds, and especially greater than 3 seconds and less than 30 seconds, during which the film has the third temperature (T3).

[0467] 3. A method for manufacturing single-layer or multi-layer thin films, wherein the method comprises at least the following steps:

[0468] The step of extruding one or co-extruding multiple layers to obtain an extruded film;

[0469] The step of simultaneously biaxially stretching the extruded film; and

[0470] The step of heat setting the stretched film;

[0471] The film contains a first polyethylene (PE1) at a mass fraction of more than 30%, preferably more than 40%, more than 50%, more than 65%, more than 80%, and especially more than 90% relative to the total mass of the film.

[0472] The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³.3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0473] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA);

[0474] The film is cooled to a first temperature (T1) below 20°C, preferably below 15°C, and especially below 10°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after extrusion.

[0475] Wherein, the tensile coefficient (V) along the machine direction or longitudinal direction (MD) MD The value should be greater than 5.0, preferably greater than 6.0, especially greater than 7.0, and less than 8.0;

[0476] Wherein, the tensile coefficient (V) along the transverse direction (TD) TD The value should be greater than 4.0, preferably greater than 5.0, especially greater than 6.0, and less than 7.0;

[0477] Wherein, the tensile coefficient (V) along the machine direction (MD) MD The elongation factor (V) is greater than that along the transverse direction (TD). TD );

[0478] The film has a second temperature (T2) during the stretching process that is greater than 120°C and less than 180°C, preferably greater than 130°C and less than 170°C, and especially greater than 140°C and less than 160°C.

[0479] The film is heated from the first temperature (T1) to the second temperature (T2) within a time period of 1 to 18 seconds, preferably 1.5 to 12 seconds, and especially 2 to 9 seconds before stretching.

[0480] The duration (Δt) (=t2-t1) between the first time point (t1) when the film reaches the second temperature (T2) and the second time point (t2) when the film begins to stretch is 0.05 seconds to 3 seconds, preferably 0.1 seconds to 3 seconds, and especially 0.3 seconds to 1.5 seconds;

[0481] The film, during the heat setting period, has a third temperature (T3) greater than 60°C and less than 200°C, preferably greater than 80°C and less than 180°C, and particularly greater than 100°C and less than 160°C; and

[0482] Wherein, the dwell time during the heat setting period (= duration of heat setting of the film) is greater than 2 seconds and less than 60 seconds, preferably greater than 3 seconds and less than 45 seconds, especially greater than 4 seconds and less than 30 seconds, and the film has the third temperature (T3) during the heat setting period.

[0483] 4. The method according to any one of numbers 1 to 3, wherein the method further specifies relaxing the film during the heat setting of the film;

[0484] Wherein, the relaxation coefficient (R) along the machine direction (MD) MD The value is greater than 0.00 and less than 0.10, preferably greater than 0.00 and less than 0.05, and especially greater than 0.00 and less than 0.03;

[0485] Wherein, the relaxation coefficient (R) along the lateral direction (TD) TD The value is greater than 0.00 and less than 0.20, preferably greater than 0.00 and less than 0.10, and particularly greater than 0.00 and less than 0.05; and

[0486] Wherein, the relaxation coefficient (R) along the lateral direction (TD) TD The relaxation coefficient (R) is greater than that along the machine direction (MD). MD ).

[0487] 5. The method according to number 4, wherein the thin film has the third temperature (T3) during the relaxation period; and

[0488] The relaxation duration of the film is greater than 2 seconds, preferably greater than 3 seconds, especially greater than 4 seconds, and less than 45 seconds, preferably less than 30 seconds, during which the film has the third temperature (T3).

[0489] 6. The method according to any one of numbers 1 to 5, wherein the method further specifies cooling the film after stretching and before heat setting;

[0490] The film is cooled to a fourth temperature (T4) below 50°C, preferably below 40°C, and especially below 30°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after stretching.

[0491] 7. The method according to any one of numbers 1 to 6, wherein the film comprises a first polypropylene (PP1); and

[0492] The first polypropylene (PP1) has a heat deflection temperature greater than 75°C, preferably greater than 85°C, and especially greater than 95°C, which is measured according to ASTM D648-18.

[0493] 8. The method according to any one of numbers 1 to 7, wherein the thin film is multilayered;

[0494] The film has at least one layer, preferably an outer layer and / or an inner layer, wherein the outer layer and / or the inner layer comprises or is composed of a second polyethylene (PE2);

[0495] The second polyethylene (PE2) has a content of less than 0.94 g / cm³. 3 Preferably less than 0.92 g / cm³ 3 and greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN EN ISO 1183-1:2019-09.

[0496] 9. The method according to any one of numbers 1 to 8, wherein the thin film is multilayered;

[0497] The film has at least one layer, preferably an outer layer and / or an inner layer, wherein the outer layer and / or the inner layer comprises or is composed of a third polyethylene (PE3) and / or a third polypropylene (PP3).

[0498] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0499] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0500] 10. The method according to any one of numbers 1 to 9, wherein the thin film is multilayered;

[0501] The film contains ethylene-vinyl alcohol copolymer (EVOH) in a mass fraction of less than or equal to 5%, preferably less than 5%, relative to the total mass of the film;

[0502] The film has at least one intermediate layer, which comprises or is composed of ethylene-vinyl alcohol copolymer (EVOH);

[0503] Wherein, the at least one intermediate layer comprising ethylene-vinyl alcohol copolymer (EVOH) does not contain polyethylene (PE) and does not contain polypropylene (PP); and

[0504] Preferably, the intermediate layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) is surrounded on both sides by layers each comprising a tackifier (HV).

[0505] 11. The method according to any one of numbers 1 to 10, wherein the thin film is multilayered;

[0506] The film contains polyvinyl alcohol copolymer (PVOH) in a mass fraction of less than or equal to 5%, preferably less than 5%, relative to the total mass of the film;

[0507] The film has at least one intermediate layer, which comprises or is composed of polyvinyl alcohol copolymer (PVOH);

[0508] Wherein, the at least one intermediate layer comprising polyvinyl alcohol copolymer (PVOH) does not contain polyethylene (PE) and does not contain polypropylene (PP); and

[0509] Preferably, the central layer comprising or composed of polyvinyl alcohol copolymer (PVOH) is surrounded on both sides by layers each comprising a tackifier (HV).

[0510] 12. The method according to any one of numbers 1 to 9, wherein the film does not contain ethylene-vinyl alcohol copolymer (EVOH) and does not contain polyvinyl alcohol copolymer (PVOH).

[0511] 13. The method according to any one of numbers 1 to 9, wherein the thin film has an outer layer and an inner layer;

[0512] The outer layer does not contain ethylene-vinyl alcohol copolymer (EVOH) and does not contain polyvinyl alcohol copolymer (PVOH); and

[0513] The inner layer does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH).

[0514] 14. The method according to any one of numbers 1 to 13, wherein the film does not contain any of the following polymers selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0515] 15. The method according to any one of numbers 1 to 14, wherein the thin film is multilayered;

[0516] The film has at least one layer composed of the first polyethylene (PE1), and the film also has at least one layer composed of the second polyethylene (PE2); or

[0517] The film has at least one layer composed of the first polyethylene (PE1), and the film also has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); or

[0518] The film has at least one layer composed of the first polyethylene (PE1), and the film has at least one layer composed of the second polyethylene (PE2), and the film has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3).

[0519] 16. The method according to any one of numbers 1 to 15, wherein the thin film is multilayered;

[0520] The film has at least one layer composed of the first polypropylene (PP1) and at least one layer composed of the second polyethylene (PE2); or

[0521] The film has at least one layer composed of the first polypropylene (PP1), and the film also has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); or

[0522] The film has at least one layer composed of the first polypropylene (PP1), and the film has at least one layer composed of the second polyethylene (PE2), and the film has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3).

[0523] 17. The method according to any one of numbers 1 to 16, wherein the thin film is multilayered;

[0524] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1); and

[0525] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0526] 18. The method according to any one of numbers 1 to 17, wherein the thin film is multilayered;

[0527] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0528] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2); and

[0529] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0530] 19. The method according to any one of numbers 1 to 18, wherein the thin film is multilayered;

[0531] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0532] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0533] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0534] 20. The method according to any one of numbers 1 to 19, wherein the thin film is multilayered;

[0535] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0536] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2);

[0537] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0538] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0539] 21. The method according to any one of numbers 1 to 20, wherein the thin film is multilayered;

[0540] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1); and

[0541] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0542] 22. The method according to any one of numbers 1 to 21, wherein the thin film is multilayered;

[0543] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0544] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2); and

[0545] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0546] 23. The method according to any one of numbers 1 to 22, wherein the thin film is multilayered;

[0547] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0548] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0549] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0550] 24. The method according to any one of numbers 1 to 23, wherein the thin film is multilayered;

[0551] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0552] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2);

[0553] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0554] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0555] 25. The method according to any one of numbers 1 to 24, wherein the method does not include the step of laminating or extruding a layer of the film or its components, particularly a layer of the film; and / or

[0556] The film is multilayered, and the co-extrusion of the multilayered film is performed in a single step.

[0557] 26. The method according to any one of numbers 1 to 25, wherein the thin film is multilayered;

[0558] The film has at least one outer layer and / or inner layer, preferably an inner layer, which comprises a second polymer (PM2), preferably a second polyolefin (PO2), or is composed of a second polymer (PM2) and preferably a second polyolefin (PO2).

[0559] The second polymer (PM2), preferably the second polyolefin (PO2), is preferably sealable, especially heat-sealable, and preferably comprises polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMA), or any mixture thereof, or is composed of polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMA), or any mixture thereof.

[0560] 27. The method according to any one of numbers 1 to 26, wherein the thin film is multilayered;

[0561] The film has at least one outer layer and / or inner layer, preferably an outer layer, which comprises a third polymer (PM3), preferably a third polyolefin (PO3), or is composed of a third polymer (PM3), preferably a third polyolefin (PO3);

[0562] The third polymer (PM3), preferably the third polyolefin (PO3), is preferably non-sealable, even more preferably non-heat-sealable, and has a sealing temperature higher than that of the second polymer (PM2), preferably the second polyolefin (PO2), and preferably comprises polyethylene (PE) and / or polypropylene (PP) or any mixture thereof, or is composed of polyethylene (PE) and / or polypropylene (PP) or any mixture thereof.

[0563] 28. A single-layer or multi-layer, extruded, simultaneously biaxially stretched and heat-set film, said film preferably manufactured according to any one of numbers 1 to 27.

[0564] The film comprises a first polyethylene (PE1);

[0565] The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0566] The film comprises the first polyethylene (PE1) in a mass fraction greater than 30%, preferably greater than 40%, preferably greater than 55%, preferably greater than 65%, preferably greater than 80%, and particularly greater than 90% relative to the total mass of the film; and

[0567] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0568] 29. A single-layer or multi-layer, extruded, simultaneously biaxially stretched and heat-set film, said film preferably manufactured according to any one of numbers 1 to 27.

[0569] The film comprises a first polyethylene (PE1);

[0570] The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09;

[0571] The film comprises the first polyethylene (PE1) in a mass fraction greater than 40%, preferably greater than 50%, preferably greater than 65%, preferably greater than 80%, and particularly greater than 90% relative to the total mass of the film; and

[0572] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0573] 30. The film according to number 28 or 29, wherein the film is not laminated.

[0574] 31. The film according to any one of numbers 28 to 30, wherein the film is relaxed;

[0575] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 5.0 and less than 7.0, preferably greater than 5.5 and less than 7.0, and especially greater than 6.0 and less than 7.0;

[0576] The residual tensile coefficient (RV) of the film along the transverse direction (TD) TD The value is greater than 4.0 and less than 6.0, preferably greater than 4.5 and less than 6.0, and especially greater than 5.0 and less than 6.0; and

[0577] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0578] The thin film is relaxed;

[0579] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 7.0. TD () Greater than 4.0 and less than 6.0; and

[0580] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0581] The thin film is relaxed;

[0582] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.5 and less than 7.0. TD () Greater than 4.5 and less than 6.0; and

[0583] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0584] The thin film is relaxed;

[0585] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 6.0 and less than 7.0. TD () Greater than 5.0 and less than 6.0; and

[0586] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

[0587] 32. The film according to any one of numbers 28 to 30,

[0588] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density;

[0589] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 3.6 and less than 3.9, preferably greater than 4.1 and less than 4.4, and especially greater than 5.0 and less than 5.4;

[0590] The residual tensile coefficient (RV) of the film along the transverse direction (TD) TD The value is greater than 2.8 and less than 3.4, preferably greater than 3.6 and less than 3.9, and especially greater than 4.1 and less than 4.4; and

[0591] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0592] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density;

[0593] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 3.6 and less than 3.9. TD () Greater than 2.8 and less than 3.4; and

[0594] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0595] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density;

[0596] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 4.1 and less than 4.4. TD () Greater than 3.6 and less than 3.9; and

[0597] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0598] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density;

[0599] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 5.4. TD () Greater than 4.1 and less than 4.4; and

[0600] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

[0601] 33. The film according to any one of numbers 28 to 30,

[0602] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density;

[0603] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 5.0 and less than 7.0, preferably greater than 5.5 and less than 7.0, and especially greater than 6.0 and less than 7.0;

[0604] The residual tensile coefficient (RV) of the film along the transverse direction (TD) TD The value is greater than 4.0 and less than 6.0, preferably greater than 4.5 and less than 6.0, and especially greater than 5.0 and less than 6.0; and

[0605] The residual tensile coefficient (RV) of the film along the machine direction (MD) MDThe residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0606] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density;

[0607] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 7.0. TD () Greater than 4.0 and less than 6.0; and

[0608] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0609] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density;

[0610] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.5 and less than 7.0. TD () Greater than 4.5 and less than 6.0; and

[0611] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or

[0612] The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density;

[0613] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 6.0 and less than 7.0. TD() Greater than 5.0 and less than 6.0; and

[0614] The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

[0615] 34. The film according to any one of numbers 28 to 33, wherein the film comprises a first polypropylene (PP1); and

[0616] The first polypropylene (PP1) has a heat deflection temperature greater than 75°C, preferably greater than 85°C, and especially greater than 95°C, which is measured according to ASTM D648-18.

[0617] 35. The film according to any one of numbers 28 to 34, wherein the film is multilayered;

[0618] The film has at least one layer, preferably an outer layer and / or an inner layer, wherein the outer layer and / or the inner layer comprises or is composed of a second polyethylene (PE2);

[0619] The second polyethylene (PE2) has a content of less than 0.94 g / cm³. 3 Preferably less than 0.92 g / cm³ 3 and greater than 0.87 g / cm 3 The density of polyethylene (PE) is measured according to DIN ENISO 1183-1:2019-09.

[0620] 36. The film according to any one of numbers 28 to 35, wherein the film is multilayered;

[0621] The film has at least one layer, preferably an outer layer and / or an inner layer, wherein the outer layer and / or the inner layer comprises or is composed of a third polyethylene (PE3) and / or a third polypropylene (PP3).

[0622] The third polyethylene (PE3) has a density that is less than the density of the first polyethylene (PE1) and greater than the density of the second polyethylene (PE2); and

[0623] The third polypropylene (PP3) has a heat distortion temperature that is lower than that of the first polypropylene (PP1) and higher than that of the second polypropylene (PP2).

[0624] 37. The film according to any one of numbers 28 to 36, wherein the film is multilayered;

[0625] The film contains ethylene-vinyl alcohol copolymer (EVOH) in a mass fraction of less than or equal to 5%, preferably less than 5%, relative to the total mass of the film;

[0626] The film has at least one intermediate layer, which comprises or is composed of ethylene-vinyl alcohol copolymer (EVOH);

[0627] Wherein, the at least one intermediate layer comprising ethylene-vinyl alcohol copolymer (EVOH) does not contain polyethylene (PE) and does not contain polypropylene (PP); and

[0628] Preferably, the intermediate layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) is surrounded on both sides by layers each comprising a tackifier (HV).

[0629] 38. The film according to any one of numbers 28 to 36, wherein the film is multilayered;

[0630] The film contains polyvinyl alcohol copolymer (PVOH) in a mass fraction of less than or equal to 5%, preferably less than 5%, relative to the total mass of the film;

[0631] The film has at least one intermediate layer, which comprises or is composed of polyvinyl alcohol copolymer (PVOH);

[0632] Wherein, the at least one intermediate layer comprising polyvinyl alcohol copolymer (PVOH) does not contain polyethylene (PE) and does not contain polypropylene (PP); and

[0633] Preferably, the central layer comprising or composed of polyvinyl alcohol copolymer (PVOH) is surrounded on both sides by layers each comprising a tackifier (HV).

[0634] 39. The film according to any one of numbers 28 to 36, wherein the film does not contain ethylene-vinyl alcohol copolymer (EVOH) and does not contain polyvinyl alcohol copolymer (PVOH).

[0635] 40. The film according to any one of numbers 28 to 36, wherein the film has an outer layer and an inner layer;

[0636] The outer layer does not contain ethylene-vinyl alcohol copolymer (EVOH) and does not contain polyvinyl alcohol copolymer (PVOH); and

[0637] The inner layer does not contain ethylene-vinyl alcohol copolymer (EVOH) or polyvinyl alcohol copolymer (PVOH).

[0638] 41. The film according to any one of numbers 28 to 40, wherein the film does not contain any of the following polymers selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0639] 42. The film according to any one of numbers 28 to 41, wherein the film is multilayered;

[0640] The film has at least one layer composed of the first polyethylene (PE1), and the film also has at least one layer composed of the second polyethylene (PE2); or

[0641] The film has at least one layer composed of the first polyethylene (PE1), and the film also has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); or

[0642] The film has at least one layer composed of the first polyethylene (PE1), and the film has at least one layer composed of the second polyethylene (PE2), and the film has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3).

[0643] 43. The film according to any one of numbers 28 to 42, wherein the film is multilayered;

[0644] The film has at least one layer composed of the first polypropylene (PP1) and at least one layer composed of the second polyethylene (PE2); or

[0645] The film has at least one layer composed of the first polypropylene (PP1), and the film also has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); or

[0646] The film has at least one layer composed of the first polypropylene (PP1), and the film has at least one layer composed of the second polyethylene (PE2), and the film has at least one layer composed of the third polyethylene (PE3) and / or the third polypropylene (PP3).

[0647] 44. The film according to any one of numbers 28 to 43, wherein the film is multilayered;

[0648] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1); and

[0649] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0650] 45. The film according to any one of numbers 28 to 44, wherein the film is multilayered;

[0651] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0652] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2); and

[0653] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0654] 46. ​​The film according to any one of numbers 28 to 45, wherein the film is multilayered;

[0655] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0656] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0657] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0658] 47. The film according to any one of numbers 28 to 46, wherein the film is multilayered;

[0659] The film has at least one layer, the layer comprising or composed of the first polyethylene (PE1);

[0660] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2);

[0661] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0662] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0663] 48. The film according to any one of numbers 28 to 47, wherein the film is multilayered;

[0664] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1); and

[0665] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0666] 49. The film according to any one of numbers 28 to 48, wherein the film is multilayered;

[0667] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0668] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2); and

[0669] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0670] 50. The film according to any one of numbers 28 to 49, wherein the film is multilayered;

[0671] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0672] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0673] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0674] 51. The film according to any one of numbers 28 to 50, wherein the film is multilayered;

[0675] The film has at least one layer, the layer comprising or composed of the first polypropylene (PP1);

[0676] The film has at least one layer, the layer comprising or composed of the second polyethylene (PE2);

[0677] The film comprises at least one layer comprising or composed of the third polyethylene (PE3) and / or the third polypropylene (PP3); and

[0678] The film has at least one layer comprising or composed of ethylene-vinyl alcohol copolymer (EVOH) and / or polyvinyl alcohol copolymer (PVOH).

[0679] 52. The film according to any one of numbers 28 to 51, wherein the film comprises a single layer, the single layer being composed of a first polyethylene (PE1); or

[0680] The film is composed of multiple, preferably two, three, four or five layers, each of which is composed of the first polyethylene (PE1).

[0681] 53. The film according to any one of numbers 28 to 52, wherein the film is multilayered;

[0682] The film has at least one outer layer and / or inner layer, preferably an inner layer, which comprises a second polymer (PM2), preferably a second polyolefin (PO2), or is composed of a second polymer (PM2) and preferably a second polyolefin (PO2).

[0683] The second polymer (PM2), preferably the second polyolefin (PO2), is preferably sealable, especially heat-sealable, and preferably comprises polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMA), or any mixture thereof, or is composed of polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMA), or any mixture thereof.

[0684] 54. The film according to any one of numbers 28 to 52, wherein the film is multilayered;

[0685] The film has at least one outer layer and / or inner layer, preferably an outer layer, which comprises a third polymer (PM3), preferably a third polyolefin (PO3), or is composed of a third polymer (PM3), preferably a third polyolefin (PO3);

[0686] The third polymer (PM3), preferably the third polyolefin (PO3), is preferably non-sealable, even more preferably non-heat-sealable, and has a sealing temperature higher than that of the second polymer (PM2), preferably the second polyolefin (PO2), and preferably comprises polyethylene (PE) and / or polypropylene (PP) or any mixture thereof, or is composed of polyethylene (PE) and / or polypropylene (PP) or any mixture thereof.

[0687] 55. The film according to any one of numbers 28 to 54, wherein the film has an outer layer composed of a first polypropylene PP1;

[0688] The film has an inner layer, which is composed of a first polyethylene PE1, a second polyethylene PE2, or a third polyethylene PE3.

[0689] The first polypropylene PP1 has a heat deflection temperature greater than 75°C, preferably greater than 85°C, and especially greater than 95°C, which is measured according to ASTM D648-18.

[0690] The second polyethylene PE2 has a content of less than 0.940 g / cm³. 3 Preferred concentration is less than 0.920 g / cm³. 3 and greater than 0.870 g / cm 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and

[0691] The third polyethylene PE3 has a density that is less than that of the first polyethylene PE1 and greater than that of the second polyethylene PE2, and these densities are each measured according to DIN EN ISO 1183-1:2019-09.

[0692] 56. The film according to any one of claims 28 to 55, wherein the film is multilayered;

[0693] The film contains an ethylene-vinyl alcohol copolymer (EVOH) at a mass fraction of less than 5% relative to the total mass of the film; and

[0694] The film has at least one layer composed of an ethylene-vinyl alcohol copolymer (EVOH); or

[0695] The thin film is multilayered;

[0696] The film comprises polyvinyl alcohol copolymer (PVOH) in a mass fraction of less than 5% relative to the total mass of the film; and

[0697] The film has at least one layer composed of a polyvinyl alcohol copolymer (PVOH).

[0698] 57. The first polyethylene (PE1) is used for single-layer or multi-layer, extruded, biaxially stretched and heat-set films, preferably for films according to any one of numbers 28 to 56, or for the manufacture of said films;

[0699] The film contains the first polyethylene (PE1) in a mass fraction of more than 30%, preferably more than 40%, more than 50%, more than 65%, more than 80%, and especially more than 90% relative to the total mass of the film.

[0700] The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferably greater than 0.950 g / cm³ 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and

[0701] The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

[0702] 58. The use as described in number 57, wherein the film comprises a first polypropylene (PP1); and

[0703] The first polypropylene (PP1) has a heat deflection temperature greater than 75°C, preferably greater than 85°C, and especially greater than 95°C, which is measured according to ASTM D648-18.

[0704] 59. The film according to any one of numbers 28 to 56 is used as a ready-to-use packaging material for food, or for manufacturing a ready-to-use packaging material for food by laminating another polymer layer or a plurality of additional polymer layers or a package consisting of a plurality of polymer layers.

Claims

1. A method for manufacturing single-layer or multi-layer thin films, wherein, The method comprises at least the following steps: The step of extruding one or co-extruding multiple layers to obtain an extruded film; The step of simultaneously biaxially stretching the extruded film; and The step of heat setting the stretched film; The film comprises a first polyethylene (PE1); The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferred concentration is greater than 0.950 g / cm³. 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; The film contains the first polyethylene (PE1) in a mass fraction of more than 30%, preferably more than 40%, more than 50%, more than 65%, more than 80%, and especially more than 90% relative to the total mass of the film. The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA); Among them, the tensile coefficient (V) along the machine direction (MD) MD The elongation factor (V) is greater than that in the transverse direction (TD). TD ); The film, during the stretching process, has a second temperature (T2) greater than 120°C and less than 180°C, preferably greater than 130°C and less than 170°C, and particularly greater than 140°C and less than 160°C; and The film has a third temperature (T3) during the heat setting process, which is greater than 60°C and less than 200°C, preferably greater than 80°C and less than 180°C, and especially greater than 100°C and less than 160°C.

2. The method according to claim 1, in, The film is cooled to a first temperature (T1) below 20°C, preferably below 15°C, and especially below 10°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after extrusion. The film is heated from the first temperature (T1) to the second temperature (T2) within a time period of 1 to 18 seconds, preferably 1.5 to 12 seconds, and especially 2 to 9 seconds before stretching. Wherein, the duration (Δt) (=t2-tl) between the first time point (t1) when the film reaches the second temperature (T2) and the second time point (t2) when the film begins to stretch is 0.05 seconds to 6 seconds, preferably 0.1 seconds to 3 seconds, especially 0.3 seconds to 1.5 seconds; and The dwell time during the heat setting period (= duration of heat setting of the film) is greater than 1 second and less than 60 seconds, preferably greater than 2 seconds and less than 45 seconds, and especially greater than 3 seconds and less than 30 seconds, during which the film has the third temperature (T3).

3. The method according to claim 1 or 2, in, The tensile factor (V) along the machine direction or longitudinal direction (MD) MD Values ​​greater than 5.0, preferably greater than 6.0, especially greater than 7.0, and less than 8.0; Wherein, the tensile coefficient (V) along the transverse direction (TD) TD Values ​​greater than 4.0, preferably greater than 5.0, especially greater than 6.0, and less than 7.0; and Wherein, the dwell time during the heat setting period (= duration of heat setting of the film) is greater than 2 seconds and less than 60 seconds, preferably greater than 3 seconds and less than 45 seconds, especially greater than 4 seconds and less than 30 seconds, and the film has the third temperature (T3) during the heat setting period.

4. The method according to any one of claims 1 to 3, wherein, The method further includes relaxing the film during the heat setting of the film; Wherein, the relaxation coefficient (R) along the machine direction (MD) MD The value is greater than 0.00 and less than 0.10, preferably greater than 0.00 and less than 0.05, and especially greater than 0.00 and less than 0.03; Wherein, the relaxation coefficient (R) along the lateral direction (TD) TD The value is greater than 0.00 and less than 0.20, preferably greater than 0.00 and less than 0.10, and particularly greater than 0.00 and less than 0.05; and Wherein, the relaxation coefficient (R) along the lateral direction (TD) TD The relaxation coefficient (R) is greater than that along the machine direction (MD). MD ).

5. The method according to claim 4, wherein, The film has the third temperature (T3) during the relaxation period; and The relaxation duration of the film is greater than 2 seconds, preferably greater than 3 seconds, especially greater than 4 seconds, and less than 45 seconds, preferably less than 30 seconds, during which the film has the third temperature (T3).

6. The method according to any one of claims 1 to 5, wherein, The method further includes cooling the film after stretching and before heat setting; The film is cooled to a fourth temperature (T4) below 50°C, preferably below 40°C, and especially below 30°C within a time period of 0.01 to 1 second, preferably 0.05 to 0.5 seconds, and especially 0.07 to 0.3 seconds after stretching.

7. The method according to any one of claims 1 to 6, wherein, The method does not include the step of laminating or extruding the film or its components, particularly the layers of the film; and / or The film is multilayered, and the co-extrusion of the multilayered film is performed in a single step.

8. A single-layer or multi-layer, extruded, simultaneously biaxially stretched and heat-set film, preferably manufactured according to the method according to any one of claims 1 to 7. in, The film comprises a first polyethylene (PE1); The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferred concentration is greater than 0.950 g / cm³. 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; The film comprises the first polyethylene (PE1) in a mass fraction greater than 30%, preferably greater than 40%, preferably greater than 50%, preferably greater than 65%, preferably greater than 80%, and particularly greater than 90% relative to the total mass of the film; and The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

9. The thin film according to claim 8, wherein, The film is not laminated.

10. The thin film according to claim 8 or 9, wherein, The film is relaxed; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 5.0 and less than 7.0, preferably greater than 5.5 and less than 7.0, and especially greater than 6.0 and less than 7.0; The residual tensile coefficient (RV) of the film along the transverse direction (TD) TD The value is greater than 4.0 and less than 6.0, preferably greater than 4.5 and less than 6.0, and especially greater than 5.0 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The thin film is relaxed; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 7.

0. TD () Greater than 4.0 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The thin film is relaxed; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.5 and less than 7.

0. TD () Greater than 4.5 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The thin film is relaxed; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 6.0 and less than 7.

0. TD () Greater than 5.0 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

11. The film according to claim 8 or 9, in, The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 3.6 and less than 3.9, preferably greater than 4.1 and less than 4.4, and especially greater than 5.0 and less than 5.4; The residual tensile coefficient (RV) of the film along the transverse direction (TD) TD The value is greater than 2.8 and less than 3.4, preferably greater than 3.6 and less than 3.9, and especially greater than 4.1 and less than 4.4; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 3.6 and less than 3.

9. TD () Greater than 2.8 and less than 3.4; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 4.1 and less than 4.

4. TD () Greater than 3.6 and less than 3.9; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.960 g / cm³. 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 5.

4. TD () Greater than 4.1 and less than 4.4; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

12. The film according to claim 8 or 9, in, The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The value is greater than 5.0 and less than 7.0, preferably greater than 5.5 and less than 7.0, and especially greater than 6.0 and less than 7.0; The residual tensile coefficient (RV) of the film along the transverse direction (TD) TD The value is greater than 4.0 and less than 6.0, preferably greater than 4.5 and less than 6.0, and especially greater than 5.0 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.0 and less than 7.

0. TD () Greater than 4.0 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 5.5 and less than 7.

0. TD () Greater than 4.5 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD );or The film is relaxed, and the first polyethylene (PE1) has a density greater than 0.940 g / cm³. 3 And less than or equal to 0.960 g / cm³ 3 The density; The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) of the film along the transverse direction (TD) is greater than 6.0 and less than 7.

0. TD () Greater than 5.0 and less than 6.0; and The residual tensile coefficient (RV) of the film along the machine direction (MD) MD The residual tensile coefficient (RV) is greater than that along the transverse direction (TD). TD ).

13. The thin film according to any one of claims 8 to 12, wherein, The film consists of a single layer, which is composed of a first polyethylene (PE1); or The film is composed of multiple, preferably two, three, four or five layers, each of which is composed of the first polyethylene (PE1).

14. The film according to any one of claims 8 to 13, wherein, The film is multilayered; The film has at least one outer layer and / or an inner layer, preferably an inner layer, the inner layer comprising a second polymer (PM2), preferably a second polyolefin (PO2), or the inner layer being composed of a second polymer (PM2) and preferably a second polyolefin (PO2); The second polymer (PM2), preferably the second polyolefin (PO2), is preferably sealable, especially heat-sealable, and preferably comprises polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMA), or any mixture thereof, or is composed of polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer (IO), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMA), or any mixture thereof.

15. The film according to any one of claims 8 to 14, wherein, The film is multilayered; The film has at least one outer layer and / or one inner layer, preferably an outer layer, the outer layer comprising a third polymer (PM3), preferably a third polyolefin (PO3), or the outer layer being composed of a third polymer (PM3), preferably a third polyolefin (PO3); The third polymer (PM3), preferably the third polyolefin (PO3), is preferably non-sealable, more preferably non-heat-sealable, and has a sealing temperature higher than that of the second polymer (PM2), preferably the second polyolefin (PO2). The third polyolefin (PO3) preferably comprises polyethylene (PE) and / or polypropylene (PP) or any mixture thereof, or is composed of polyethylene (PE) and / or polypropylene (PP) or any mixture thereof.

16. The film according to any one of claims 8 to 15, wherein, The film has an outer layer, which is composed of the first polypropylene (PP1); The film has an inner layer, which is composed of a first polyethylene (PE1), a second polyethylene (PE2), or a third polyethylene (PE3). The first polypropylene (PP1) has a heat deflection temperature greater than 75°C, preferably greater than 85°C, and especially greater than 95°C, which is measured according to ASTM D648-18. The second polyethylene (PE2) has a content of less than 0.940 g / cm³. 3 Preferred concentration is less than 0.920 g / cm³. 3 and greater than 0.870 g / cm 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and The third polyethylene (PE3) has a density that is less than that of the first polyethylene (PE1) and greater than that of the second polyethylene (PE2), and these densities are each measured according to DIN EN ISO 1183-1:2019-09.

17. The film according to any one of claims 8 to 16, wherein, The film is multilayered; The film contains an ethylene-vinyl alcohol copolymer (EVOH) at a mass fraction of less than 5% relative to the total mass of the film; and The film has at least one layer composed of an ethylene-vinyl alcohol copolymer (EVOH); or The thin film is multilayered; The film comprises polyvinyl alcohol copolymer (PVOH) in a mass fraction of less than 5% relative to the total mass of the film; and The film has at least one layer composed of a polyvinyl alcohol copolymer (PVOH).

18. The first polyethylene (PE1) is used for single-layer or multi-layer, extruded, biaxially stretched and heat-set films, preferably for films according to any one of claims 8 to 17, or for the manufacture of said films; in, The film contains the first polyethylene (PE1) in a mass fraction of greater than 30%, preferably greater than 40%, preferably greater than 50%, preferably greater than 65%, preferably greater than 80%, and especially greater than 90% relative to the total mass of the film. The first polyethylene (PE1) has a content greater than 0.940 g / cm³. 3 Preferred concentration is greater than 0.950 g / cm³. 3 Especially greater than 0.960 g / cm 3 and less than or equal to 1.010 g / cm³ 3 Preferred concentration is less than 1.000 g / cm³. 3 Especially less than 0.970 g / cm³ 3 The density, which is measured according to DIN EN ISO 1183-1:2019-09; and The film does not contain any of the following polymers, which are selected from the group consisting of polyethylene terephthalate (PET), polyvinylidene chloride (PVDC), and polyamide (PA).

19. The film according to any one of claims 8 to 17, as a ready-to-use packaging material for food, or for use in manufacturing ready-to-use packaging materials for food by laminating another polymer layer or a plurality of additional polymer layers or packaging consisting of a plurality of polymer layers.

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