Polyethylene-based arrangement

Abstract

The invention relates to a Polyethylene-based arrangement (8) with a thickness of less than 250 µm for the storage of grain, silage, warm or wet industrial products, comprising at least one outer layer (1), at least one inner layer (7) and only one barrier layer (5). The arrangement (8) comprises at least one PE based functional layer (3) to reduce the oxygen permeability of the polyethylene-based arrangement (8) to less than 50 cm3 / m2 d bar according to ASTM D3985.

Description

[0001] RKW V693

[0002] Polyethylene-based arrangement.

[0003] Description

[0004] The invention relates to a polyethylene-based arrangement with a thickness of less than 250 pm for the storage of grain, silage, warm or wet industrial products, comprising at least one outer layer, at least one inner layer and only one barrier layer.

[0005] For example, the polyethylene-based arrangement is used as a tubular film or silage tube. Tubular film ensiling is an efficient, flexible and environmentally friendly technology for preserving and storing all types of animal feed or wet industrial products in a specially developed tubular film. Originally developed for the ensiling of green waste, today a wide variety of substrates can be stored in silage tubes. Silage tubes are also used for composting organic material. Today, for example, pressed pulp as well as maize and grass silage are also stored in silage tubes.

[0006] A typical silage tube comprises at least two layers and is approx. 120 m long and 5 m in diameter. Accordingly, high demands are placed on a silage tube in terms of tensile strength and puncture resistance.

[0007] Special machines are required to fill the silage tubes, which usually first crush the material to be stored and then press it into the tubes. DE 10 2010 046 183 A1 describes such a device.

[0008] Silage tubes require a barrier against oxygen and water vapour in order to maintain the quality of the feed in the silage. Silage is created by the anaerobic (oxygen-free) fermentation process in which lactic acid bacteria ferment the plant material. The exclusion of oxygen prevents undesirable microorganisms, such as moulds or yeasts, from decomposing the material and impairing the quality of the silage. Oxygen would disrupt the fermentation process and lead to putrefaction, RKW V693

[0009] 2 making the feed unusable for animals. When oxygen enters the silage tubes, it can lead to oxidation of nutrients, especially carbohydrates and proteins. This reduces the nutritional value of the silage, which has a negative impact on animal health and feed efficiency. Moulds and yeasts can grow in an oxygen-rich environment, which not only spoil the silage, but also produce harmful mycotoxins that can cause illness in the animals. A barrier against water vapour prevents moisture from penetrating the silage from the outside. Too much moisture inside can lead to incorrect fermentation, while too little moisture can also disrupt fermentation. Correct moisture control ensures that the silage remains stable and retains its desired consistency.

[0010] Sealing against oxygen is of crucial importance for ensiling. Traditionally, stable polyethylene-based films have been used for silage tubes. However, the use of these conventional films has repeatedly led to the formation of mold due to the penetration of oxygen.

[0011] Conventional films for silage tubes based on typically conventional polyolefins would have to be very thick to ensure sufficient impermeability to oxygen and would therefore be heavy and relatively expensive to produce.

[0012] The use of EVOH as a barrier material leads to excellent barrier results, but EVOH cannot provide sufficient mechanical properties for use in silage tubes.

[0013] For this reason, films with special barrier arrangements were developed for silage tubes. These barrier arrangements are polymers that have a particularly high impermeability to gases, especially oxygen.

[0014] DE 698 17 012 T2 describes a multi-layer film for agricultural silage products. The film has a layer made of a polyamide that acts as an oxygen barrier. The film product can consist of two or more layers, for example co-extruded layers, of which at least one layer or possibly even several layers consist of an insulating RKW

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[0016] 3 plastic layer. In the case of a multilayer film with at least two insulating layers, these insulating layers may consist of the same plastic material or of different plastic materials, all of which are airtight.

[0017] DE 10 2009 052 948 B4 describes a covering system for silage with an underlay film made of a polyamide and a silage film made of a polyethylene.

[0018] Polyamide has excellent puncture resistance, but the tear resistance is often not sufficient for the challenging use as a silage tube in agriculture.

[0019] DE 10 2017 107 060 A1 discloses a method for increasing the tear resistance of a multilayer film. The multilayer film has at least one barrier arrangement which comprises a total thickness for reducing gas permeability. According to the invention, the barrier arrangement is divided into at least two layers to increase the tear resistance.

[0020] The European Union aims to reduce the landfilling of plastic waste as part of its "Green Deal". By 2030, 55 % of plastic packaging waste is to be recycled. This poses completely new challenges for the production and construction of silage bags, tubes and films.

[0021] In order to meet the challenges of recycling, the design of packaging must become increasingly sustainable. This can be achieved, for example, by realizing and implementing more mono-material constructions. The challenge here lies in achieving the previously known barrier effect with just one recyclable monomaterial construction of a silage sleeve.

[0022] Furthermore, the silage tube must also be able to achieve the mechanical properties achieved to date. Otherwise, the silage tubes could burst during filling or tear during transportation. RKW V693

[0023] 4

[0024] Furthermore, the proportion of known barrier materials such as EVOH and / or polyamide must be reduced in order to meet the requirements of recycling, ideally without impairing the barrier properties.

[0025] The task of the present invention is to make the polyethylene-based arrangement thinner than previously known arrangements in order to fulfil the future requirements of the Plastics Pact 2025. In addition, the arrangement should be designed to be fully recyclable. The polyethylene-based arrangement should also be suitable for packaging and storing grain, silage, warm or wet industrial products. In addition, the polyethylene-based arrangement should be able to exhibit the mechanical properties achieved to date. In addition, the arrangement should be able to be produced very inexpensively in order to be competitive in the agriculture sector, which is under price pressure.

[0026] According to the invention, this task is ensured by a polyethylene-based arrangement, a method and a use according to the subsidiary main claims. Preferred variants can be found in the sub-claims, the description, the embodiment example and the drawings.

[0027] According to the invention, the arrangement comprises at least one PE based functional layer to reduce the oxygen permeability of the polyethylene-based arrangement to less than 50 cm3 / m2d bar according to ASTM D3985.

[0028] The polyethylene-based arrangement can be designed, for example, as a silage bag, silage tube, silage plane or as a silage tarpaulin.

[0029] To fulfill its task, a silage tube must have a specific oxygen impermeability. This is the only way to ensure an appropriate fermentation process during ensiling, e.g. in the silage tube, or impermeability to chemicals in the case of disinfection films. RKW V693

[0030] 5

[0031] For example, the polyethylene-based arrangement has an oxygen permeability of less than 45 cm3 / m2d bar, preferably less than 35 cm3 / m2d bar, in particular less than 25 cm3 / m2d bar at 23°C and 50 % relative humidity in accordance with ASTM D3985.

[0032] The water vapor permeability of dry or moisture-sensitive goods is determined in accordance with DIN 53116 or ASTM D6701-01 using a gravimetric measurement method. A test container filled with a desiccant is sealed with a sample of foil and exposed to a defined test climate. The amount of water permeating through the sample is determined by weighing. A quantity of water in a range of 1 - 200 g / (m2■ d) can be detected. The detection limit is also dependent on the composition and thickness of the sample.

[0033] For example, the polyethylene-based arrangement has a water vapour permeability of less than 20 g / m2in 24 h according to ASTM D6701-01 .

[0034] In a variant of the invention, the polyethylene-based arrangement has a water vapor permeability of less than 15 g / m2, preferably less than 10 g / m2, in particular less than 5 g / m2in 24 h according to ASTM D6701-01. This makes the storage of grain, silage, warm or wet industrial products particularly advantageous, whereby the silage material is coated for a particularly long time.

[0035] For example, the polyethylene-based arrangement has a dart drop according to ASTM D1709 of more than 8 g / pm.

[0036] The puncture resistance of the film is determined in accordance with ASTM D1709, which specifies a standardized test method for evaluating the impact resistance of plastic films using a freely falling dart. In this method, a circular film sample is clamped in a test frame and subjected to an impact by a falling steel dart of defined mass. The dart weight is adjusted stepwise until the point is reached at which 50 % of the tested samples are punctured. This value, referred RKW V693

[0037] 6 to as F50, represents a characteristic measure of the puncture resistance of the film. The standard distinguishes between two procedures, in which either a dart with a diameter of 38 mm is dropped from a height of 0.66 m or a dart with a diameter of 51 mm is dropped from a height of 1.50 m. The test is carried out under defined environmental conditions, typically at 23 °C and 50 % relative humidity. The result is expressed either as the dart mass in grams or as the corresponding impact energy in joules and provides an indication of the toughness and energy absorption capacity of the film under dynamic loading. For improved comparability between films of different thicknesses, the puncture resistance can additionally be expressed as a thickness-normalized value in grams per micrometre (g / pm), representing the specific energy absorption per unit thickness of the film.

[0038] In one variant of the invention, the polyethylene-based arrangement has a dart drop according to ASTM D1709 of more than 9 g / pm.

[0039] For another example, the polyethylene-based arrangement has a dart drop according to ASTM D1709 of more than 10 g / pm.

[0040] In one variant of the invention, the polyethylene-based arrangement has an instrumented puncture energy density, determined according to ISO 6603-2 or ASTM D3763, of more than 6 J / cm3, measured at 23 °C and 50 % relative humidity.

[0041] The impact behavior of the film was evaluated in accordance with ISO 6603-2 and ASTM D3763, which both describe instrumented puncture impact tests for plastic films and sheets. These standardized methods determine the energy required to puncture a specimen using a hemispherical impactor at a defined velocity, thereby providing detailed information about the impact strength and fracture behavior of the material under dynamic loading conditions. RKW V693

[0042] 7

[0043] According to ISO 6603-2, the test is performed with a circular specimen that is clamped in a support ring and impacted at its center by a hemispherical striker. The impact event is instrumented, allowing the continuous measurement of force, deflection, and energy absorption throughout the penetration process. From the resulting force-deflection curve, key parameters such as the maximum force, total energy to break, and the mode of failure (ductile or brittle) can be determined. The test is carried out at a defined impact velocity, typically between 1 m / s and 4.4 m / s, and at standard climatic conditions of 23 °C and 50 % relative humidity.

[0044] The corresponding ASTM D3763 standard describes an equivalent procedure for determining the high-speed puncture resistance of plastic materials using an instrumented impact tester. It provides a similar data profile, recording the force, deformation, and energy absorbed until specimen rupture. The results are expressed as total energy to failure (Joules), maximum load (Newtons), and deflection at maximum load (millimeters). Both standards thus enable a comprehensive characterization of the dynamic puncture performance of films and multilayer structures, particularly in applications where mechanical impact resistance is critical.

[0045] For improved comparison of films with different thicknesses, the total impact energy obtained from ISO 6603-2 or ASTM D3763 may additionally be normalized by the specimen thickness, yielding a specific energy value in J / mm or J / mm3, which represents the intrinsic energy absorption capacity of the material.

[0046] For example, the polyethylene-based arrangement has an instrumented puncture energy density, determined according to ISO 6603-2 or ASTM D3763, of more than 7 J / cm3, measured at 23 °C and 50 % relative humidity. RKW V693

[0047] 8

[0048] In another variant of the invention, the polyethylene-based arrangement has an instrumented puncture energy density, determined according to ISO 6603-2 or ASTM D3763, of more than 7,5 J / cm3, measured at 23 °C and 50 % relative humidity.

[0049] The tear resistance of the film is determined in accordance with ASTM D1922, which specifies a standardized pendulum method (Elmendorf type) for evaluating the resistance of plastic films and thin sheets to the propagation of a tear. In this method, a rectangular film specimen with a defined pre-cut is mounted in a clamping device, and a pendulum of known energy is released to continue the tear through the remaining uncut portion of the sample. The energy absorbed by the specimen during tear propagation is measured and used to calculate the tear resistance of the film. The test is typically performed in both the machine direction (MD) and the cross direction (CD) under controlled environmental conditions, usually at 23 °C and 50 % relative humidity. The result is expressed as the average tearing force in millinewtons (mN) or newtons (N) and provides an indication of the toughness and resistance of the film to crack propagation under mechanical stress. For better comparability between films of different thicknesses, the tear resistance may also be expressed as a thickness- normalized value in millinewtons per micrometre (mN / pm), representing the specific tear resistance per unit thickness of the film.

[0050] The polyethylene-based arrangement has a tear resistance in MD according to ASTM 1922 of more than 20 g / pm, preferably more than 25 g / pm, in particular more than 30 g / pm. This makes the silage hose particularly tear-resistant during the filling process as well as during transport and storage.

[0051] The polyethylene-based arrangement has a tear resistance in CD according to ASTM 1922 of more than 30 g / pm, preferably more than 35 g / pm, in particular more than 40 g / pm. RKW

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[0054] The polyethylene-based arrangement has a Spencer puncture Energy according to ASTM3420 of more than 2000 mJ, preferably more than 2350 mJ, in particular more than 2700 mJ. The special structure and the specially selected raw materials produce a film for silage tubes that can withstand the enormous mechanical stresses that occur when filling or plugging the hose.

[0055] The Elmendorf test according to DIN 53128 determines the average force in grams or mN required to tear a sample after the tearing process has been initiated. During the test, one or more layers of the film are torn with a pendulum over a defined distance. The force applied during tearing is measured by the loss of potential energy of the pendulum.

[0056] In one variant of the invention, the polyethylene-based arrangement has a tensile strength in the machine direction according to Elmendorf DIN 53128 of more than 20 — , preferably more than 25 — , in particular more than 30 — . This means that |im |im |im the silage tube is optimally prepared for the challenge during the filling process and effectively prevents the silage tube from traveling.

[0057] The special physical parameters of the silage tube are achieved through the selection and combination of suitable raw materials, whereby the structure of the silage tube in particular plays a decisive role in achieving the properties.

[0058] At the same time, the special design and special structure of a silage tube consisting of several layers can also significantly reduce the thickness of the tube compared to known tubes.

[0059] For example, the polyethylene-based arrangement has a thickness of less than 240 pm, preferably less than 220 pm, in particular less than 200 pm. RKW

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[0062] In a particularly advantageous variant of the invention, the thickness of the polyethylene-based arrangements is 180 pm.

[0063] By reducing the thickness of the silage tube while maintaining excellent mechanical properties, the requirements of the EU Plastics Pact can be met in particular. The volume of polyethylene-based arrangements is significantly reduced, although the same amount of silage tubes can be used.

[0064] For example, the polyethylene-based arrangement has a seven-layer structure.

[0065] In a further variant, the polyethylene-based arrangement is designed with five layers, whereby, in contrast to the seven-layer variant, the outer and inner layers are each not designed as a double layer.

[0066] A version with nine layers is also conceivable.

[0067] For example, the polyethylene-based arrangement has a seven-layer structure. In the middle, at least one central layer is surrounded by a barrier layer and a functional layer.

[0068] In one variant of the invention, a connecting layer is also arranged between the barrier layer and the outer layer and also a connecting layer is arranged between the functional layer ad the inner layer.

[0069] In a further embodiment, the barrier layer and the functional layer can also be arranged in reverse order.

[0070] For example, the Polyethylene (PE) of the at least one PE based functional layer has a density according to ISO 1183-1 of more than 0.925 g / cm3and less than 0.930 g / cm3. RKW V693

[0071] 11

[0072] The molecular weight distribution (MWD) describes the distribution of molecular weights or chain lengths of molecules in a sample, especially in polymers. Since polymers consist of chains with varying lengths, they do not have a uniform molecular mass, but a range of masses. The molecular weight distribution indicates how these masses are distributed in the sample. A measure of the width of the molecular weight distribution, defined as the polydispersity index (PDI).

[0073] A PDI value of 1 means that all molecules have the same mass (monodisperse), while larger values indicate a broad distribution (polydisperse). The molecular weight distribution influences the properties of polymers, such as viscosity, melting point, mechanical strength and solubility. Polymers with a narrow distribution (small PDI) often show a more uniform behaviour, while polymers with a broad distribution (high PDI) can have more complex properties. Methods such as gel permeation chromatography (GPC) or light scattering are used to measure the molecular weight distribution in polymers.

[0074] In one variant of the invention, the PE of the at least one PE based functional layer has a PDI according to ISO 16014 of less than 2.

[0075] Short-chain branching (SCB) refers to the presence of short side chains in the main chain of a polymer, typically in polyolefins such as polyethylene or polypropylene. These side chains often consist of a few carbon atoms (e.g. methyl, ethyl or butyl groups) and are formed by incomplete polymerization processes, such as those that occur in the production of low-density polyethylene (LDPE) or certain copolymers.

[0076] SCB reduces the density of the polymer as the branches prevent the molecular chains from packing tightly together. The short branches reduce the ability of the polymer to form ordered, crystalline structures, which can lead to a semicrystalline or amorphous material. The presence of SCB affects the flexibility, RKW V693

[0077] 12 strength and toughness of the polymer. Polymers with more SCB usually have a lower melting point.

[0078] For example, the PE of the at least one PE based functional layer has a shortchain branching (SCB) of 5 - 20 SCB per 1000 carbon atoms.

[0079] Elongation at Break is a mechanical parameter that describes the ability of a material to stretch before it tears under load. It is specified as a percentage change in length in relation to the original length of the material. Materials with a high elongation at break can stretch considerably without breaking, which indicates high ductility or elasticity.

[0080] In one variant of the invention, the PE of the at least one PE based functional layer has an elongation at break according to ISO 527-1 of more than 400 %, preferably more than 550 %, in particular more than 700 %.

[0081] All these special features of the PE of the PE-based functional layer realise a functional layer that comes very close to the mechanical properties and barrier properties of a polyamide, whereby an otherwise conventional barrier layer can be replaced by this special PE-based functional layer.

[0082] This provides silage tubes which, with a high oxygen impermeability and a flexible behavior, simultaneously have a high tear resistance, so that undesired bursting or tearing is prevented and at the same time only a relatively low thickness of the multilayer film is required, so that the polyethylene-based arrangement according to the invention is relatively light.

[0083] In addition, the embodiment of the polyethylene-based arrangement according to the invention realizes for the first time a variant which is also considered recyclable according to the new specifications of the European Union and which RKW V693

[0084] 13 also proves itself in the practical implementation of recycling due to the reduced use of the polyamide with only one very thin layer.

[0085] For example, the thickness of the barrier layer is more than 5 pm and less than 20 pm. This means that the barrier layer is particularly thin and saves material, while still having excellent barrier properties.

[0086] In addition, the proportion of the barrier layer is less than 5 % by weight of the polyethylene-based arrangement and therefore fully complies with the European Union's specifications for the recyclability of plastic films.

[0087] For example, polyamide of the barrier layer has a density according to ISO 1183- 1 of more than 1.08 g / cm3, preferably more than 1.10 g / cm3and / or less than 1 .20 g / cm3, preferably less than 1.16 g / cm3.

[0088] In a variant of the invention, the polyamide of the barrier layer has a tensile strength at break of more than 80 MPa, preferably of more than 100 MPa and / or of less than 200 MPa, preferably of less than 160 MPa.

[0089] DIN EN ISO 11357 is a standard for the determination of thermal properties of plastics, including melting and softening temperatures, specific heat capacity, thermal conductivity and other thermal transitions. The standard specifies various techniques for thermal analysis, including differential scanning calorimetry (DSC), thermogravimetry (TG), dynamic mechanical analysis (DMA) and other methods. These methods enable the characterization of temperature dependencies of various thermal properties.

[0090] Polyamides used for silage films usually have melting temperatures of over 220 °C. Special polyamides, for example, have melting temperatures of 207 °C. However, these temperatures are still too high for the silage films, which preferably consist of a high proportion of polyethylene, to be recycled after their RKW V693

[0091] 14 intended use. The polyamide with high melting points leads to low bubble stability and high die temperatures, which have an unfavorable effect on the mechanical properties of the downstream products.

[0092] In a particularly advantageous variant of the invention, the polyamide of the barrier layer has a melting point of less than 179 °C according to DIN EN ISO 11357. This previously unattained low melting point of a polyamide component produces a polyethylene-based arrangement specially for silage tubes that can be excellently recycled in accordance with the task.

[0093] In particular, the low melting point of the polyamide in the barrier layers results in a recyclate of the polyethylene-based arrangement which, due to the lower overall melting point, is better suited for all processes that allow the recyclate to be reused in a valuable way.

[0094] In different variations of the invention, the barrier layer is a polyamide / polyolefin plastic alloy.

[0095] In one embodiment the polyamide and the polyolefin are combined into a mechanically recyclable polymer alloy exhibiting improved oxygen- and aromabarrier properties compared with non-modified polyethylene layers.

[0096] In one variant the polyolefin component of the plastic alloy comprises high- density polyethylene (HDPE), linear low-density polyethylene (LLDPE) or a mixture thereof.

[0097] In one embodiment the polyamide component is selected from polyamide 6, polyamide 66, polyamide 6 / 66, polyamide MXD6, polyamide 6I / 6T or mixtures thereof, wherein the plastic alloy preferably comprises 5 - 45 wt-% polyamide and 55 - 95 wt-% polyolefin. RKW V693

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[0099] In one variant the alloy further comprises 0.3 - 8 wt-% of a compatibilizer, in particular a maleic-anhydride-grafted polyolefin or epoxy-functionalized elastomer promoting interfacial adhesion between the polyamide and polyolefin phases.

[0100] In one embodiment the polyamide is dispersed in the polyolefin matrix with a volume-average domain size below 2 pm, preferably below 1 pm, thereby forming a fine-morphology co-continuous or droplet structure that provides the barrier effect.

[0101] A polyamide / polyolefin plastic alloy is a two-phase thermoplastic system in which a polyamide component is finely dispersed within a polyolefin matrix. The two phases differ in polarity and mechanical function: while the polyamide phase provides excellent gas and aroma barrier properties as well as high thermal resistance, the polyolefin phase — particularly polyethylene — contributes toughness, ductility, and weldability. By means of suitable compatibilizers, for example maleic anhydride-modified polyolefins, the interfacial adhesion between the phases can be improved, resulting in a uniform dispersion of the polyamide domains. In this way, a mechanically recyclable plastic alloy is obtained that combines the advantages of both polymer classes within a homogeneous structure.

[0102] In one advantageous embodiment, the barrier layer of the film arrangement may be formed as a polyethylene-based polymer alloy comprising a polyethylene matrix with a dispersed polyamide phase. The polyethylene matrix constitutes the continuous phase, while the polyamide phase is present as discrete domains embedded within the matrix. This morphology allows the superior barrier properties of the polyamide to be combined with the ductility and processability of polyethylene. Due to the fine dispersion of the polyamide domains, the material exhibits a uniform, stress-dissipating structure that provides particular benefits under dynamic load conditions. RKW V693

[0103] 16

[0104] Furthermore, it has been found that the mechanical properties, especially puncture resistance and tear resistance, can be significantly improved when the barrier layer is formed as a polyamide / polyethylene alloy. Pure polyamide layers tend to exhibit brittle fracture behavior and limited elongation, leading to crack initiation under impact stress. By embedding the polyamide phase within a flexible polyethylene matrix, the impact energy can be more effectively distributed and absorbed, resulting in a more ductile fracture mode. At the same time, the dispersed polyamide domains act to stabilize the tear propagation, thereby enhancing the tear resistance in both machine and transverse directions compared to homogeneous polyamide layers.

[0105] Another advantage of the polyamide / polyolefin alloy lies in its improved recyclability. Whereas pure polyamide barrier layers typically impair the material recycling of polyolefin-based films, the unified thermoplastic matrix structure of the alloy enables joint reprocessing without phase separation. Consequently, the barrier layer not only improves the mechanical performance of the film but also contributes to a more sustainable material cycle.

[0106] In one variant of the invention, at least one connecting layer adjoins between the barrier layer and the functional layer.

[0107] For example, a central layer is arranged between the barrier layer and the functional layer.

[0108] The central layer, for example, is made of a very soft polyethylene (PE).

[0109] The very soft polyethylene can be made from LDPE or mLLDPE or a mixture. The polyethylene (PE) has a density of more than 0.906 g / cm3and less than 0.912 g / cm3, preferably less than 0.910 g / cm3. RKW V693

[0110] 17

[0111] At least one connecting layer and the central layer has proportion of a maleic anhydride grafted concentrate with more than 5 % by weight and less than 20 % by weight.

[0112] For example, the maleic anhydride grafted concentrate grade has a density according to ISO 1183-1 of more than 0.919 g / cm3and is less than 0.921 g / cm3, and a MFI (at 190 °C at 2.16 kg) according to ISO 1133-1 is more than 0.1 g / 10 min and is less than 0.5 g / 10 min.

[0113] For example, the connecting layer comprises least 60 % by weight of an LLDPE with an MFI of more than 0.8 and least 5 % by weight of a maleic anhydride grafted concentrate grade. At the same time, this ensures enormous tear resistance, while also securing the connection to the barrier layer and the functional layer.

[0114] In one variant of the invention, the proportion of LLDPE in the connecting layer is more than 70 % by weight and less than 90 % by weight.

[0115] The production of LLDPE is initiated by transition metal catalysts, in particular Ziegler or Philips type catalysts. The actual polymerization process can be carried out either in the solution phase or in gas phase reactors. As a rule, octene is the comonomer in the solution phase, while butene and hexene are copolymerized with ethylene in a gas phase reactor. LLDPE has a higher tensile strength and a higher impact and puncture resistance than LDPE. It is very flexible and expands under load. It can be used to produce thinner films that have better resistance to stress cracking. It has good resistance to chemicals. It has good electrical properties. However, it is not as easy to process as LDPE, has a lower gloss and a narrower range for heat sealing.

[0116] For example, the proportion of a maleic anhydride grafted concentrate grade in the connecting layer is more than 10 % by weight and less than 20 % by weight. RKW V693

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[0118] The flow behavior of polyolefins is described using the melt flow rate respectively the MFI according to ISO 1133-1 , usually at a temperature of 190 °C for polyethylene at a load of 2.16 kg, 5 kg or 21.6 kg. A higher melt flow index correlates with a lower average molecular weight of the polymer. At the same time, the higher the melt index of a polymer, the lower the melt viscosity, which is advantageous for a high output of the extrusion system. On the other hand, polymers with a high molecular weight, i.e. a low melt index, are advantageous in terms of mechanical stability, in particular tensile strength or toughness.

[0119] For example, the connecting layer has a proportion of LLDPE which density according to ISO 1183-1 is more than 0.918 g / cm3and is less than 0.922 g / cm3, and which MFI (at 190 °C at 2.16 kg) according to ISO 1133-1 is more than 0.9 g / 10 min and is less than 1 .1 g / 10 min.

[0120] For example, the connecting layer has a proportion of a maleic anhydride grafted concentrate grade which density according to ISO 1183-1 is more than 0.919 g / cm3and is less than 0.921 g / cm3, and which MFR (at 190 °C at 2.16 kg) according to ISO 1133-1 is more than 0.1 g / 10 min and is less than 0.5 g / 10 min.

[0121] In one variant of the invention the outer layer and the inner layer comprises least 50 % by weight of an mLLDPE with a MFI of less than 0.6 and at least 15 % by weight LLDPE with a MFI of more than 0.8.

[0122] By way of example, the proportion of mLLDPE in the outer layer and / or the inner layer is more than 55 % by weight and less than 80 % by weight. The proportion of mLLDPE in the outer layer and / or the inner layer advantageously increases the stability of the silage tube.

[0123] For example, the outer layer and / or the inner layer has a proportion of LLDPE. The proportion of LLDPE greatly increases the tear resistance of the outer layer RKW

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[0125] 19 and / or the inner layer. Exemplarily, the amount of LLDPE in the outer layer and / or the inner layer is more than 15 % by weight and / or less than 35 % by weight.

[0126] In one variant of the invention, the outer and / or the inner layer has a proportion of mLLDPE which density according to ISO 1183-1 is more than 0.920 g / cm3and is less than 0.922 g / cm3, and which MFR (at 190 °C at 2.16 kg) according to ISO 1133-1 is more than 0.3 g / 10 min and is less than 0.55 g / 10 min.

[0127] For example, the outer and / or the inner layer has a proportion of LLDPE which density according to ISO 1183-1 is more than 0.918 g / cm3and is less than 0.922 g / cm3, and which Ml (at 190 °C at 2.16 kg) according to ISO 1133-1 is more than 0.85 g / 10 min and is less than 1 .5 g / 10 min.

[0128] In a variant of the invention, the outer layer has a proportion of a titanium dioxide TiO2. This is preferably coated TiO2. Due to the proportion of titanium dioxide, the outer layer is white, whereby an excellent reflection of sunlight can be achieved and thus an excellent protection of the silage material can be realized.

[0129] For example, the titanium dioxide is integrated in a white polybatch. In a variant of the invention, the outer layer has a proportion of white polybatch of more than 5 wt.% and less than 20 wt.%.

[0130] In a further variant of the invention, the connecting layers also have a proportion of white polybatch with titanium dioxide, the proportion in the intermediate layer being more than 5 % by weight and less than 20 % by weight.

[0131] For example, the functional layer also has a proportion of white polybatch with titanium dioxide, whereby the proportion in the intermediate layer is more than 5 % by weight and less than 20 % by weight. RKW V693

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[0133] The CIELAB color space is commonly applied in the evaluation and control of the color properties of polymer films across various industries. This color space provides a standardized, device-independent framework for measuring color and reflection, making it ideal for ensuring consistency and accuracy in the production of polymer films.

[0134] During the production process, manufacturers can use spectrophotometers to measure the L*, a*, and b* values of the films. These instruments capture how the film reflects or transmits light, and then convert that data into Lab values. This information helps assess whether the color of a film meets the specified target values or tolerances.

[0135] For example, the outer layer respectively the polyethylene-based arrangement has a reflection according to Lab value of more than 60 %, preferably more than 70 %, in particular more than 80 %. In this advantageous way, the high-energy solar radiation can be reflected and thus the contents of the silage hose can be effectively protected.

[0136] In a variant of the invention, the inner layer has a proportion of a black pigment.

[0137] For example, the inner layer also has a proportion of black polybatch, whereby the proportion in the inner layer is more than 5 % by weight and less than 20 % by weight.

[0138] According to the invention, a polyethylene-based assembly is produced by a process in which an outer layer of polyethylene, a barrier layer of polyamide, , three connecting layers and an inner layer of polyethylene are produced by coextrusion, wherein at least one PE based functional layer with a special PE is co-extruded to the polyethylene-based arrangement to reduce the thickness of less than 250 pm and to reduce the oxygen permeability to less than 30 cm3 / m2d bar according to ASTM D3985. RKW V693

[0139] 21

[0140] The extruders for blown film coextrusion are usually arranged in a ring around the blowing ring. The raw material, usually plastic granulate or powder, is fed into the hopper. The hopper ensures that the material is fed evenly into the extruder. The extruder screw is the central element of the extruder and is driven by an electric motor in the extrusion barrel. The screw has a helical shape and rotates to melt and advance the plastic material. The screw is divided into different zones, whereby the temperature is increased zone by zone from the hopper to the nozzle. For this purpose, the extrusion barrel is designed as a heated container with several heated zones to ensure precise control of the temperature along the extruder screw. The nozzle is located at the end of the extrusion cylinder. This is where the molten plastic strand is formed before being fed into the blowing ring. In the blowing ring, the melted plastic strand is blown into a flat tube, which is then inflated into a bubble. The blowing ring is tempered to control the temperature of the melted film. After the bubble is formed, the film is passed through a cooling section where cooling air streams or water sprays are used to lower the temperature and stabilize the film. The drawing device pulls the extruded film away from the bubble and ensures a uniform thickness and width. This process defines the final mechanical properties of the polyethylene-based arrangement. The finished polyethylene-based arrangement is rolled up on a winder.

[0141] The special temperature management and control realizes a polyethylene-based arrangement which is advantageously recyclable due to its properties, in particular its melting temperature and its almost unmixed design.

[0142] According to the invention, the polyethylene-based arrangement is used as recyclable silage tube for storing grain, silage, warm or wet industrial products.

[0143] As a result, polyethylene-based arrangement is provided which, with a high oxygen impermeability and a flexible behavior, simultaneously have a high tear RKW V693

[0144] 22 resistance, so that undesired bursting or tearing is prevented and at the same time only a relatively small thickness of the polyethylene-based arrangement is required, so that the silage tube according to the invention is relatively light. By using the PE-based functional layer, the arrangement can be presented at a particularly low cost.

[0145] Further advantages and features of the invention are apparent from the description of an embodiment example with reference to drawings and from the drawings themselves.

[0146] In this connection

[0147] Fig. 1 a schematic representation of the polyethylene-based arrangement,

[0148] Fig. 2 another schematic representation of the polyethylene-based arrangement.

[0149] Fig. 1 and 2 shows a polyethylene-based arrangement 8 with seven layers for a silage tube.

[0150] In this embodiment, the outer layer 1 is made of a proportion of mLLDPE, whereas the outer layer 1 comprise 61 % by weight of an mLLDPE with a melting temperature of 113 °C and whereas MFI of the mLLDPE is 0.45. In addition, the outer layer 1 has a proportion of LLDPE, whereas the outer layer 1 comprise 25 % by weight of an LLDPE with a melting temperature of 119 °C and whereas MFI of the LLDPE is 1.0. The outer layer 1 also contains a proportion of white masterbatch, whereas outer layer 1 comprise 7 % by weight of a white Masterbatch and whereas MFI of the white masterbatch is 15.0. Furthermore, the outer layer 1 contains additives and flow aids of 6 % by weight. RKW V693

[0151] 23

[0152] The connecting layers 2 and 6 are made of a proportion of LDPE, whereas the connecting layers 2 and 6 comprise 53.5 % by weight of an LDPE with a melting temperature of 116 °C and whereas MFI of the LDPE is 0.27. In addition, the connecting layers 2 and 6 have a proportion of a further LDPE, whereas the connecting layers 2 and 6 comprise 20 % by weight of an LDPE and whereas MFI of the LDPE is 0.25. The connecting layers 2 and 6 also contain a proportion of white masterbatch, whereas the connecting layers 2 and 6 comprise 12 % by weight of a white Masterbatch and whereas MFI of the white masterbatch is 15.0. The proportion of a maleic anhydride grafted concentrate grade in the connecting layers 2 and 6 are 10 % by weight, whereas MFI of the maleic anhydride grafted concentrate grade is 0.3. Furthermore, the connecting layers 2 and 6 contains additives and flow aids of 4 % by weight.

[0153] The central layer 4 is made of a very soft LDPE, whereby the LDPE has a density of 0.910 g / cm3. The proportion of a maleic anhydride grafted concentrate grade in the central layer is 10 % by weight.

[0154] The barrier layer 5 is made of a copolyamide PA 6 / 6.6, whereby the melting point of the copolyamide PA 6 / 6.6 is 179 °C.

[0155] The functional layer 3 is made of a proportion of PE with a melting temperature of 124 °C and whereas MFI according to ASTM D1238 of the PE is 0.85. The PE has a dart drop impact according to ASTM D1709 of 2100 g and a haze of 61 % according to ASTM D1003.

[0156] Fig. 1 and 2 shows different arrangements of the barrier layer 5 and the functional layer 3. In one embodiment is the functional layer 3 near the outer layer 1 arranged and in another embodiment is the barrier layer 5 near the outer layer 1 arranged. RKW

[0157] V693

[0158] 24

[0159] The inner layer 7 is made of a proportion of mLLDPE, whereas the inner layer 7 comprise 63.5 % by weight of an mLLDPE with a melting temperature of 113 °C and whereas MFI of the mLLDPE is 0.45. In addition, the inner layer 7 has a proportion of LLDPE, whereas the inner layer 7 comprise 25 % by weight of an LLDPE with a melting temperature of 119 °C and whereas MFI of the LLDPE is 1.0. The inner layer 7 also contains a proportion of black masterbatch, whereas inner layer 7 comprise 8 % by weight of a black masterbatch and whereas MFI of the black masterbatch is 15.0. Furthermore, the inner layer 7 contains additives and flow aids of 4 % by weight.

Claims

RKWV693Polyethylene-based arrangementClaims1 . Polyethylene-based arrangement (8) with a thickness of less than 250 pm for the storage of grain, silage, warm or wet industrial products, comprising:- at least one outer layer (1 )- at least one inner layer (7)- only one barrier layer (5), characterized in that the arrangement (8) comprises at least one PE based functional layer (3) to reduce the oxygen permeability of the polyethylene-based arrangement (8) to less than 50 cm3 / m2d bar according to ASTM D3985.

2. Polyethylene-based arrangement according to claim 1 , characterized in that the polyethylene-based arrangement (8) has a water vapour permeability of less than 20 g / m2in 24 h according to ASTM D6701-01 .

3. Polyethylene-based arrangement according to claim 1 or 2, characterized in that the barrier layer (5) being a polyamide layer.

4. Polyethylene-based arrangement according to claim 1 or 2, characterized in that, the barrier layer (5) being a polyamide / polyolefin plastic alloy.RKWV6935. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that, the barrier layer (5) has a thickness of less than 30 pm.

6. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the polyethylene-based arrangement (8) has a dart drop according to ASTM D1709 of more than 8 g / pm.

7. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the polyethylene-based arrangement (8) has a tear resistance in MD according to ASTM 1922 of more than 20 g / pm.

8. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the polyethylene-based arrangement (8) has a tear resistance in CD according to ASTM 1922 of more than 30 g / pm.RKWV6939. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the polyethylene-based arrangement (8) has an instrumented puncture energy density, determined according to ISO 6603-2 or ASTM D3763, of more than 6 J / cm3, measured at 23 °C and 50 % relative humidity.

10. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the PE of the at least one PE based functional layer (3) has a density of more than 0.925 g / cm3and less than 0.930 g / cm3.

11. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the PE of the at least one PE based functional layer (3) has a molecular weight distribution (PDI) according to ISO 16014 of less than 2.

12. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the PE of the at least one PE based functional layer (3) has a short-chain branching (SCB) of 5 - 20 SCB per 1000 carbon atoms.RKW V693413. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that at least one connecting layer (2, 6) adjoins between the barrier layer (5) and the functional layer (3).

14. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the polyethylene-based arrangement (8) comprises a central layer (4), made of a very soft polyethylene (PE), whereby the polyethylene (PE) has a density of less than 0.912 g / cm3.

15. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that at least one connecting layer (2, 6) and the central layer (4) has proportion of a maleic anhydride grafted concentrate with more than 5 % by weight and less than 20 % by weight.

16. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the outer layer (1 ) has an reflection according to Lab value of more than 60 %.

17. Polyethylene-based arrangement according to at least one of the proceeding claims, characterized in that the polyethylene-based arrangement (8) has a thickness of less than 240 pm, preferably less than 220 pm, in particular less than 200 pm.RKWV693518. Process for the manufacture of a polyethylene-based arrangement (8) comprising the following steps: extrusion of an outer layer (1 ) of a polyethylene, - extrusion of only one barrier layer (5), whereby the barrier layer (5) being a polyamide layer with a thickness of less than 30 pm, extrusion of an inner layer (7) of a polyethylene, characterized in that at least one PE based functional layer (3) is co-extruded to the polyethylene-based arrangement (8) to reduce the thickness of less than 250 pm and to reduce the oxygen permeability to less than 30 cm3 / m2d bar according to ASTM D3985.

19. Use of a polyethylene-based arrangement (8) according to any one of claims 1 to 17 as recyclable silage tube for the storage of grain, silage, warm or wet industrial products.

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