Polyethylene-based polymeric compositions usable for the production of stretch film

Abstract

Polyethylene-based polymeric composition useful for the production of stretch films with low thickness, high extensibility and excellent rheological properties, by cast film technology, and the process for obtaining it. Said composition comprising 20-90%, calculated on the total weight of the composition, of recycled plastic material (SRM), having certain chemical-physical characteristics and said material being recovered from polyethylene-based waste plastic materials derived from post-consumer.

Description

[0001]Polyethylene-based polymeric compositions usable for the production of stretch film Field of the invention The present invention concerns a polyethylene-based polymeric composition useful for the production of stretch films with low thickness, high extensibility and with excellent rheological properties, and the process for obtaining it. In particular, it concerns a polyethylene-based polymeric composition comprising recycled plastic material with certain chemical-physical characteristics. State of the art Stretch film has its greatest use in the food and beverage industry. Other uses are for example packaging for pharmaceuticals, electronic equipment, paper industry, textile industry, consumer goods, gift items, building products, or special applications such as the packaging to protect luggage destined for the cargo hold. Currently, the polymer processing technologies for the production of stretch film are mainly two: blownfilm technology consisting of the extrusion to obtainmonolayer film or co-extrusion to obtain multilayerfilm, and cast film technology, consisting of theextrusion of one or more layers of polymer through a flat-head die and subsequently the extension thereof on water-cooled rollers, called "chill roll". The latter technology allows obtaining a film characterized by a high degree of flatness, transparency and gloss, by extruding linear low density polyethylene (LLDPE) granules by means of a flat-head die. While in the blown film technology the use ofsecondary raw material alone or in a mixture with first- use polyethylene defined as "newly manufactured" and produced directly from an industrial plant, as disclosed in patent GB2218997, filed by Teno AB, has been widely described, there are a few references that disclose polymeric films produced by cast film technology andobtained by using secondary raw material, in particularcoming from waste plastic materials derived from post- consumer, defined according to standard D5491-08:2022 "Recycled post-consumer PE film sources for moulding and extrusion materials". Patent application WO2020229932, filed by Nova Chem. Int. SA, describes the production of polymeric films consisting of at least three layers, containing recycled polyethylene, obtained both by using blown film technology and with a cast film process for the production of stretch film. However, the films, obtained from the cast film process, have a maximum extensibility equal to 200%. In fact, WO2020229932 does not pose thetechnical problem of selecting the best mixture ofrecycled polyethylene to obtain polymeric films with high extensibility or to optimize other characteristics and properties, useful in the various industrial applications, of the films thus obtained. The presence of a small number of references, as reported above, is due to the strict constraints, in terms of rheological and macromolecular characteristics, of polyethylene for stretch film applications, obtainable by cast film technology. It is known, for example, that linear low density polyethylene (LLDPE) obtained by polymerization or co-polymerization of ethylene with longer-chain linearalkenes, carried out with catalysts containingtransition metals, in particular Ziegler catalysts,better meets in stretch film applications than lowdensity polyethylene (LDPE), derived from polymerization or co-polymerization of ethylene with linear longer- chain alkenes, carried out by radical processes, andthen the respective LLDPE / LDPE mixtures as reported in"Modeling of internal residual stress in linear andbranched polyethylene films during cast film extrusion: towards a prediction of heat-shrinkability", Journal of Materials Processing Technology, volume 271, September 2019, p. 599-608. In addition, the distribution of the molecular weights of linear low density polyethylene LLDPE, in terms of Mw and Mw / Mn, is another important factor, which affects the definition of the extensibility characteristics of a polyethylene film, obtained by cast film technology, as reported by Mark A. Spalding and Ananda M. Chatterjee in "Handbook of Industrial Polyethylene and Technology Definitive Guide to Manufacturing, Properties, Processing, Applications and Markets", 2017 edition, John Wiley & Sons, Inc. The melt flow rate (MFR) also has a strong impacton the mechanical properties of the polyethylene films for stretch applications, as described by G. M. McNally, C. M. Small, W. R. Murphy and G. Garrett in "The Effect of Polymer Properties on the Mechanical Behavior andMorphological Characteristics of Cast Polyethylene Filmfor Stretch and Cling Film Applications", Journal of Plastic Film and Sheeting, 2005, pp. 21-39. It is known that recycled plastic materials arecharacterized by having a heterogeneous polymeric composition. The waste collection and sorting processes ensure that the recycled material is composed of a mixture of polymers and copolymers of different types, of the presence of non-polymeric contaminants, identifiable as ash content in recycled material,macromolecules deriving from the partial degradation ofthe polymeric structure, during rework at the temperature to which the collected and sorted waste must necessarily be subjected. It is therefore evident that all the factorsdescribed above make it difficult to use the recycledmaterial successfully in the production of stretch film by using cast film technology. It is also evident that it is difficult for the skilled person in the art, by using normal routine analyses, to select and characterize in a reproducible manner the polyethylene-based polymeric compositions containing recycled material useful for producingstretch films, used in high value-added applications,given the high variability of composition of the recycled material, as reported above, also due to the presence of contaminants that are sometimes difficult to characterize and eliminate with conventional washing processes. It is therefore appropriate to have films obtained from a polyethylene-based polymeric composition,comprising recycled material, by cast film technology,having a high degree of flatness, transparency,extensibility, and excellent rheological properties,very useful in the filming process, such as "strain hardening". A high degree of flatness and transparency for a polymeric film, obtained by cast film technology, is a fundamental characteristic for industrial applications with high value-added (food packaging, use in the pharmaceutical field, etc.) A high degree of extensibility is very important, especially when referred to "ecodesign" focus: in fact,the higher the extensibility of the films, the lower theamount of material to be used to package a given object. Since the stretch film, obtained by cast film technology, is widely used, this property allows a reduction in the consumption of total raw material. Having a "strain hardening", defined as the presence of an upward deviation, corresponding to aninflection point, in the curve that outlines the trendof the elongational viscosity over time, of the polyethylene-based polymeric composition in the moltenstate, gives higher processability to the polymericfilm, obtainable from said composition. The Applicant has now found that it is possible to produce stretch films with excellent qualities, for example planar and transparent stretch films possessing a high degree of extensibility and some rheological characteristics useful in the production process, such as strain hardening, by cast film technology, using a polyethylene-based polymeric composition, comprising recycled material and having certain chemical-physical characteristics, some of which have never been applied to characterize polyethylene-based polymeric compositions. The proposed solution therefore makes it possible to introduce, in applications with high value-added, the use of recycled material, currently widely used only in less valuable applications such as injection moulding products, high thickness films or stretch films with reduced extensibility, obtained by blown film technology, simply by studying and selecting the polyethylene-based polymeric composition, used as a raw material for the production of stretch film by cast film technology, based on parameters measurable in the laboratory. Objects of the inventionAccording to a first aspect, the present invention therefore concerns a polyethylene-based polymeric composition having certain chemical-physicalcharacteristics, comprising a mixture of recycledplastic material, coming from post-consumer waste plastic materials, defined according to standard D5491- 08:2022, "Recycled post-consumer PE film sources for moulding and extrusion materials"; said compositionbeing used to produce, by cast film technology, stretch films having a high degree of extensibility, measured as maximum extensibility, and excellent rheological properties, such as "strain hardening". A second aspect of the present invention concerns a process for preparing the polyethylene-based polymeric composition. A further aspect of the present invention concerns granules comprising the polyethylene-based polymeric composition. A further aspect of the present invention concerns the use of the polymeric composition or of the granules comprising said composition for obtaining polymeric films by cast film technology. Brief description of the drawings Figure 1: Figure 1 is a non-limiting schematic example of a filming machine, operating by cast film technology, used to produce the films of the present invention. Figure 2: Figure 2 is a non-limiting example of the characteristic DSC thermogram, recorded during the second heating cycle of SRM-1 of the present invention, carried out from 0 to 200°C at 5°C / min. The temperatures are reported in degrees Celsius (°C) on the axis ofabscissas (x), while the heating rate is reported on theaxis of ordinates (y) and expressed in watts per gram (W / g) with the endothermic peaks directed upwards. Figure 3: Figure 3 is a non-limiting example of thecharacteristic DSC thermogram recorded during the secondheating cycle of SRM-2 of the present invention, carriedout from 0 to 200 C at 5 C / min. The temperatures arereported in degrees Celsius (°C) on the axis of abscissas (x), while the heating rate is reported on the axis of ordinates (y) and expressed in watts per gram (W / g) with the endothermic peaks directed upwards. Figure 4: Figure 4 is a non-limiting example of thecharacteristic DSC thermogram recorded during the secondheating cycle of SRM-3 of the present invention, carriedout from 0 to 200°C at 5°C / min. The temperatures arereported in degrees Celsius (°C) on the axis of abscissas (x), while the heating rate is reported on the axis of ordinates (y) and expressed in watts per gram (W / g) with the endothermic peaks directed upwards. Figure 5: Figure 5 describes the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements, carried out on a rectangular bar of MIX-1 (example 1), after maintaining at 130°C for 5 minutes, and at a Hencky strain rate of 1 s-1, with respect to the time, reported in seconds (s) on the axis of abscissas (x). Figure 6: Figure 6 describes the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates(y), of the elongational viscosity measurements, carriedout on a rectangular bar of LLDPE-4 (example 2), aftermaintaining at 130°C for 5 minutes, and at a Henckystrain rate of 1 s-1, with respect to the time reported in seconds (s) on the axis of abscissas (x). Figure 7: Figure 7 is an overlap of the graph of figure 6 with that of Figure 5. Figure 8: Figure 8 is an overlap of the graph of figure 6 with the graph describing the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements, carried out on a rectangular bar of MIX-4 (example 7), aftermaintaining at 130°C for 5 minutes, and at a Henckystrain rate of 1 s-1, with respect to the time reported in seconds (s) on the axis of abscissas (x). Figure 9: Figure 9 is an overlap of the graph of figure 6 with the graph describing the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements, carriedout on a rectangular bar of MIX-5 (example 8), aftermaintaining at 130°C for 5 minutes, and at a Henckystrain rate of 1 s-1, with respect to the time reported in seconds (s) on the axis of abscissas (x). Figure 10: Figure 10 is an overlap of the graph of figure 6 with the graph describing the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements, carried out on a rectangular bar of MIX-7 (example 10), aftermaintaining at 130°C for 5 minutes, and at a Henckystrain rate of 1 s-1, with respect to the time, reported in seconds (s) on the axis of abscissas (x). Figure 11: Figure 11 describes the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements, carried out on a rectangular bar of MIX-LL (example 11), aftermaintaining at 130°C for 5 minutes, and at a Henckystrain rate of 1 s-1, with respect to the time, reported in seconds (s) on the axis of abscissas (x). Figure 12: Figure 12 is an overlap of the graph of figure 6 with the graph describing the trend of the values, reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements with respect to time (abscissas) carried out on a rectangularbar of MIX-8 (example 12), after maintaining at 130°Cfor 5 minutes, and at a Hencky strain rate of 1 s-1, with respect to time, reported in seconds (s) on the axis of abscissas (x). Figure 13: Figure 13 is an overlap of the graph of figure6 with the graph describing the trend of the values,reported in pascal-second (Pa*s) on the axis of ordinates (y), of the elongational viscosity measurements, carried out on a rectangular bar of MIX-9 (example 13), aftermaintaining at 130°C for 5 minutes, and at a Henckystrain rate of 1 s-1, with respect to time, reported in seconds (s) on the axis of abscissas (x). Detailed description of the invention All terms used in this patent application, unless otherwise indicated, are to be understood in their ordinary meaning, as known in the technical field in which they are applied. For the purposes of the present invention, in the following description and claims, the definitions of numerical ranges include the individual values within the range and its extremes, unless otherwise specified. For the purposes of the present description and the following claims, the term "comprising" also includes the terms "which essentially consists of" or "which consists of". By the term "polymer" is meant a large-sized molecule, consisting of repeating units called monomers, which, depending on their number, determine the degree of polymerization. A monomer is a molecule or a compound, usually made up of carbon atoms and provided with functional groups, in such a way as to react, under certain conditions, with other identical or reactively complementary monomers to form the polymers. By the term "copolymer" is meant a polymer chain containing repeating units deriving from the combination of two or more different monomers. By the term "linear low density polyethylene" also defined by the acronym "LLDPE" is meant, where not expressly specified, a polyethylene polymer or,preferably, an ethylene copolymer and alkenes with morethan two carbon atoms, having a density between 0.8800 g / cm3and 0.9350 g / cm3, and an essentially linear structure. In the present invention the polymers havingmore than two types of monomers, such as terpolymers,are also included in the term "copolymer" as used herein. LLDPE can be obtained with a wide variety of catalysts including those of the Ziegler Natta type. By the term "low density polyethylene", also defined by the acronym of "LDPE", is meant a low density polyethylene with a high degree of branching along its chain, therefore with an essentially branched structure, whose density is generally between 0.9100 g / cm3and 0.9400 g / cm3. By the term high density polyethylene, also defined by the acronym "HDPE", is meant a polyethylene with a low degree of branching along the main chain, obtained through catalytic polymerization processes, which has adensity generally higher than or equal to 0.9350 g / cm3.In the present invention, the terms "recycled plastic material", "recycled material", "recycled polymeric matter", "recycled polymeric material", "polyethylene from recycling", "raw materials deriving from recycling", "plastic materials deriving fromrecycling", "secondary raw material" or by the acronym"SRM", is meant a plastic material obtained from a recycling process, said material in particular coming from waste plastic materials derived from post-consumer. By the term "post-consumer waste plastic materials" is meant the waste plastic materials of end consumers (such as waste), which comprise both domestic users and also commercial and industrial facilities or institutes that are the end users of the product. Preferably, by the term "waste plastic materials derived from post- consumer" are meant plastic materials as defined by the standard "Standard Classification for Recycled Post- Consumer Polyethylene Film Sources for Molding and Extrusion Materials" (ASTM D5491-08:2022). A non- limiting example is the mixtures of recycled plastic material referred to as SRM-1, SRM-2 and SRM-3 used in the examples. By the term "recycling process" is meant the set of operations aimed at recovering useful materials fromwaste, in particular in the present patent applicationit refers to the set of operations aimed at recovering waste plastic materials derived from post-consumer as defined above. By the term "linear low density polyethylene polymers (LLDPE) not coming from post-consumer recycled plastic material" or "LLDPE not coming from recycled plastic material" are meant all LLDPE polymers that have not been subjected to a recycling process, therefore not coming from the recovery of waste plastic materials derived from post-consumer. Preferably, by the term "linear low density polyethylene polymers (LLDPE) not coming from post-consumer recycled plastic material" are meant LLDPE polymers intended for their first use, obtained directly from the polymerization production process, which have not been subjected to any processother than the one used for their production and do notcontain other additives than those useful for theirproduction. The additives useful for their productionmay comprise antiblocking agents, slip agents,colorants, antioxidants, fluidity modifiers and polymerprocessing aids. The linear low density polyethyleneused in the examples and referred to as LLDPE-1, LLDPE- 2, LLDPE-3 and LLDPE-4 belong to this category. The term "maximum extensibility" indicates the highest extensibility value at which the film sample, obtained from the polyethylene-based polymericcomposition by cast film technology, passes the stretchtest described in the following pages. By the term "high extensibility" or "high degree of extensibility" is preferably meant a film obtained by cast film technology having maximum extensibility valueshigher than 500%.The acronym “NMR” means Nuclear Magnetic Resonance,a material analysis technique based on the measurementof the precession of the spin of protons or other nucleiwith a magnetic moment, such as carbon 13 (13C), when they are subjected to a magnetic field. By the term“integration” referred to one or more signals of the NMRspectrum, is meant the value of the area subtended to the curve, said curve being obtained after carrying out a Lorentzian deconvolution of the signals recorded by the instrument during the analysis. In the present invention both deconvolution and integration were carried out using Mestre Nova software. The acronym "DSC" means Differential Scanning Calorimetry, a type of thermal analysis widely used for the characterization of the polymers. The acronym “FT-IR” is intended to mean the FourierTransform Infrared spectroscopy technique, aspectroscopic technique normally used in the field ofanalytical chemistry and for characterization of materials. The main object of the present invention is therefore a polyethylene-based polymeric composition comprising: -20-90%, calculated on the total weight of thecomposition, of a mixture of recycled plastic material (SRM), said material being recovered from polyethylene-based waste plastic materials derivedfrom post-consumer and defined according to ASTMD5491-08:2022; -10-80%, calculated on the total weight of thecomposition, of one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, said polymers being characterized by a density, measured in a gradient column in accordance with standard ISO 1183-1:2019, between 0.8800 and 0.9350 g / cm3,and by a melt flow rate (MFR), determined at 190°Cand with a weight of 2.16 kg in accordance with standard ISO 1133-1:2022, between 1.0 and 4.0 g / 10 min; said composition being characterized by: -a 13C NMR spectrum comprising the followingsignals at 11.03, 11.19, 23.37, 32.16 and 32.62 ±0.10 ppm, wherein the percentage ratio (A%)between the value of the integration of the signal at 32.62 ± 0.10 ppm (signal A) and thesum of the values of the integrations of the signals at 32.62 (signal A), 32.16 (signal B), 23.37 (signal C), 11.19 and 11.03 ± 0.10 ppm(signal D), is between 0.2 and 4.0%, preferably between 0.3 and 2.5%; wherein said signalsrepresent 13C carbons of branching ofpolyethylene polymers constituting thecomposition; -a melt flow rate (MFR), between 1.0 and 5.5g / 10 min, preferably between 1.5 and 3.0 g / 10 min, said index being measured at 190 °C witha weight of 2.16 kg in accordance with ISO 1133- 1:2022;- a density between 0.8800 and 0.9210 g / cm3,said density being measured in a gradient column in accordance with standard ISO 1183- 1:2019;- having passed a filtration test, carried outon the polyethylene-based polymericcomposition by operating with an average massflow rate of 5 ±0.5 kg / h and with a temperatureprofile of 170°C (hopper) – 200°C (extruderbarrels) – 210°C (die), in a single screwextruder, having a diameter (D) of 30 mm, a length / diameter ratio (L / D) of 28 and including a filter, characterized by anaperture equal to 89 microns; said test beingpassed when the following condition occurs: ΔPfin < 2 ΔPinwherein: -ΔPin is the initial pressure difference,calculated after 5 minutes of testing, by subtracting the pressure measured upstream of the filter from that measured downstream of the same; -^Pfin is the final pressure difference,calculated after 60 minutes of testing,subtracting the pressure measured upstream of the filter from the pressure measured downstream of the same;- an ash content, equal to at least 0.02%,preferably between 0.03 and 2.00%, even more preferably between 0.04 and 0.25%, said content being measured as residue of a thermal post-treatment of the polyethylene-based polymeric composition carried out at a temperature of 550 ± 5°C; -a carbonyl index (CI) value between 0.7 and10.0, preferably between 0.8 and 2.0, said index being calculated as the ratio between intensities of the absorption bands present in the FT-IR spectrum at 1740 and 2020 ± 1 cm-1respectively; said spectrum being recorded by analysing a film with thickness of 500 microns, obtained from the polyethylene-based polymeric composition by moulding with a press preheated to 150 °C. The polyethylene-based polymeric composition according to the invention is a composition that, as described in detail below, is obtained after two extrusion processes interspersed with a hot filtration.Firstly, the recycled plastic mixture (SRM) is extruded,the recycled plastic mixture (SRM) is filtered and then extruded with one or more linear low-density polyethylene polymers (LLDPE), not from post-consumer recycled plastic, to give the polyethylene-based composition according to the invention. The polyethylene-based polymeric composition according to the invention is useful for obtaining stretch films by cast film technology, simultaneouslyhaving a maximum extensibility value higher than or equalto 500% and “strain hardening”. The “strain hardening”, as will be specified later, is determined, by means of elongational viscosity measurements, only if the film obtained from the polyethylene-based polymericcomposition has a maximum extensibility higher than500%. The methods for calculating maximum extensibility and evaluating the strain hardening are reported below in the description and in the experimental part. The polyethylene-based polymeric composition according to the invention has a13C-NMR spectrum recorded, as described in the analysis section of the experimental part, with a Bruker instrument, operating at a proton frequency equal to 600 MHz (150 MHz for the13C NMR), equipped with CryoProbe, Cryoplatform Prodigy Unit and Avance Neo console. In particular, the13C-NMRspectrum highlights in the range between 0-60 ppm, usedto characterize the composition, , the presence of amore intense signal, taken as reference and placed at 29.98 ppm, and other characteristic signals respectively at 11.03 and 11.19 (both defined as signal D), 23.37(signal C), 32.16 (signal B) and 32.62 ± 0.10 ppm (signalA), said signals being attributable to the carbon atoms of the various lateral alkyl groups of the polymer chains constituting the composition. The term “lateral alkylgroups” refers to the branching of polyethylene polymerchains. As is known in art, for example, LDPE is a polymer consisting of a linear main chain with the repeated unit [CH2CH2] branched with short chains (C1-C10) and long chains (> C11) along the main chain, whileLLDPE has short ramifications (C1-C10) along the main chain. It is also known that these polymers, when reprocessed by extrusion or hot filtration for example,tend to change their molecular structure by undergoingradical reactions of splitting (“chain scission”) and branching (“chain branching”) of the chains generating further ramifications. Thus, after various reprocessing operations the number of branches of these polyethylene chains, their length and their position on the main chain may vary from the initial situation. For this reason, it was decided to carry out a13C-NMR analysis on the polyethylene-based composition, which is obtained after two extrusion processes and which in turn includes a recycled plastic mixture (SRM), which has undergone atleast one extrusion process, hot filtrations, orcomparable treatments, leading to a change in branching. This analysis showed that the influence of the branching structure on the properties of the whole composition isconsiderable. Integrating the signals, reported above,by using the Mestre Nova software, adding the integrationvalues of the two resonances at 11.03 ppm and 11.19 ppm, both defined as signal D, because they both belong to methyl groups, in order to obtain a single value, and putting the sum of the integrations of the signals A, B, C and D equal to 100, it was seen that, in the polyethylene-based polymeric compositions according to the invention, the percentage ratio, defined as "A%" and reported in table 2, between the resonance signal at32.62 ± 0.10 ppm (signal A) and the sum of theintegrations of the signals at 11.03 and 11.19 (signal D), 23.37 (signal C), 32.16 (signal B) and 32.62 ± 0.10 ppm (signal A) is between 0.2 and 4.0%, preferably between 0.3 and 2.5%. Compositions having a ratio “A%”less than 0.2% or higher than 4.0%, do not allowobtaining a stretch film produced with “cast film”technology, which has a high extensibility, for examplea maximum extensibility value higher than 500%, and atthe same time having certain rheological properties suchas, for example, “strain hardening” (examples 2, 6 and11). The polymeric compositions described in examples 2 and 11, which do not fall within the invention, as they do not comprise recycled plastic material, have in facta value of ”A%” equal to 0% (table 2), have a maximumextensibility value higher than 500% (table 3), but theydo not have “strain hardening” (figures 6 and 11); whilethe composition of example 6, which shows a value of“A%” higher than 4.0% (table 2), has a maximumextensibility value less than 500% (table 3). The polyethylene-based polymeric composition according to the invention is characterized by MFRvalues, measured in accordance with standard ISO 1133-1:2022 operating at 190 °C and with a weight of 2.16 kg,between 1.0 and 5.5 g / 10 min, preferably between 1.5 and 3.0 g / 10 min. Polyethylene-based polymeric compositions comprising recycled material having MFR values less than1.0 g / 10 min or higher than 5.5 g / 10 min are not usefulfor the purposes of the invention, because they lead to the production of films having a maximum extensibilityvalue of less than 500%, when produced with “cast film"technology (examples 4 and 9, table 3). The polyethylene-based polymeric compositionaccording to the invention is characterized by density values between 0.8800 and 0.9210 g / cm3. The density of the composition was measured in a gradient column in accordance with standard ISO 1183-2:2019. Polyethylene- based polymeric compositions with densities lower than 0.8800 g / cm3do not fall within the scope of the invention, as it is known that the polymeric compositions, if they are polyethylene-based, do not have densities lower than said value. Polyethylene-basedpolymeric compositions with density values higher than0.9210 g / cm3, lead to the production of films that do not have sufficient extensibility, when produced with"cast film" technology. In fact, the stretch filmsobtained in examples 3, 4, 9, produced from polyethylene-based polymeric compositions having density valueshigher than 0.9210 g / cm3 (table 2), which do not fallwithin the scope of the invention, have maximum extensibility values lower than 500% (table 3). The polyethylene-based polymeric composition according to the invention passes a filtration test. Said filtration test consists, as described in the analysis section of the experimental part, in the extrusion of the polyethylene-based polymeric composition, carried out in a single screw extruder having a diameter of about 30 mm and a length / diameter ratio (L / D) equal to about 28, said extruder being equipped with a filter, placed upstream of the die andhaving an aperture equal to about 89 microns. This testis carried out with an average mass flow rate of 5 ±0.5kg / h and with a temperature profile of 170°C (hopper)-200°C (extruder barrels) - 210°C (die). During the filtration test, two pressure difference values are determined. The first value defined as the initial pressure difference (ΔPin), is obtained by calculating the difference between the pressure recorded upstream of the filter present in the extruder and having an aperture equal to about 89 microns, and the pressure recorded downstream of said filter after 5 minutes of filtration test, while the second value, defined as the final pressure difference (ΔPfin), is determined by calculating the difference between the pressure recorded upstream and the pressure recorded downstream of the same filter after 60 minutes of filtration test. The polyethylene- based polymeric composition passes the filtration test if the following condition occurs: ΔPfin < 2 ΔPinThe comparative example 5 is carried out as inventive example 1, with the difference that the recycled material SRM-1 has not been subjected to filtration before forming the composition MIX-1 NF, comprising SRM-1 and LLDPE-1. The composition MIX-1 NF,thus obtained, does not pass the filtration test and thefilm, produced using said composition, has a maximum extensibility lower than that of the film obtained fromthe polymeric composition of example 1 and lower than500% (table 3). The polyethylene-based polymeric composition according to the invention has an ash content equal to at least 0.02%, preferably between 0.03 and 2.00%, even more preferably between 0.04 and 0.25%. Said ash content, measured as a thermal post-treatment residue at atemperature of about 550 °C, is the result of agravimetric analysis carried out by weighing about 8 g of polyethylene-based polymeric composition in a crucible consisting of previously calibrated refractory material. The crucible is placed in a Milestone-PYRO microwave muffle set with the temperature ramp described in the analysis section of the experimental part. The residue, thus obtained, is weighed on an analytical balance to determine the percentage content of thermal post-treatment ash. Values below 0.02% would be characteristic of polymeric compositions not containing recycled material (examples 2 and 11). In fact, since the ashes come from the presence of non-polymeric material, deriving from additives present in the polymer itself or from contaminations of the polymeric material that occurred during its life cycle and / or during the recycling process thereof, it is evident that the presence in the polymeric composition of recycled material leads to a minimum detectable content thereof.On the other hand, an ash content higher than 2.0% wouldbe disadvantageous, as it would require better cleaningof the filming plants operating by cast film technology and would lead to a lower quality and less transparent product. The polyethylene-based polymeric composition according to the invention is characterized by having a carbonyl index (CI) value of between 0.7 and 10.0, preferably between 0.8 and 2.0. The carbonyl index (CI) was determined by infrared spectroscopy carried out using the Bruker Equinox 55 spectrometer on a film with thickness of 500 microns, obtained from the polyethylene-based polymeric composition, by moulding with a press preheated to 150°C, as described in the analysis section of the experimental part. Said index isdefined as the ratio between the absorbance of thevibrational peak at 1740 ± 1 cm-1, attributable to carbonyl compounds deriving from thermal oxidation of the polyethylene-based polymeric composition sample, and the normalization band at 2019-2020 ± 1 cm-1, corresponding to the internal normalization band of the thickness of the film obtained therefrom. This index istherefore used to determine the degree of oxidation ofthe composition: the growth of the IR peak relative to the band 1740 ± 1 cm-1is in fact linked to oxidative degradation effects of the polymeric material tested,said composition not containing polymer chains withcarboxylic or carbonylic groups other than thoseobtained from oxidative processes. For the purposes ofthe present invention the limit of detectability isassociated with the minimum measurable value of the absorbance of the vibrational peak at 1740 ± 1 cm-1, which is equal to 0.001. In LLDPE not coming fromrecycled plastic material, the value is typicallyundetectable and, in any case, less than or equal to0.001, which is the limit of instrumental detectability(examples 2 and 11, table 2). Said measurement wasdisclosed in P.K. Roy et al. Polymer Degradation and Stability 90, 2005, 577-585. CI values higher than 10.0 would indicate that the polymeric material must have undergone oxidative type degradation such as to negatively affect the manufacturing process of the polymeric material itself. In a preferred embodiment the polyethylene-based polymeric composition comprises 15-75% of one or more linear low density polyethylene (LLDPE) polymers, not coming from post-consumer recycled plastic material. In a particularly preferred embodiment the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material and present in said composition, are copolymers of ethylene and at least one α-olefin, present as a comonomer. In an advantageous embodiment the one or more linear low density polyethylene polymers (LLPDE), not coming from post-consumer recycled plastic material and present in said polyethylene-based polymeric composition, are copolymers of ethylene with at least one α-olefin, present as a comonomer, having from 3 to 12 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 8 carbon atoms. The α-olefin comonomer may be linear or branched and, if desired, two or more comonomers may be used. Examples of useful comonomers include propylene, butene, 1-pentene; 1-pentene with one or more methyl, ethyl or propyl substituents; 1-hexene; 1-hexene with one or moremethyl, ethyl or propyl substituents; 1-heptene with oneor more methyl, ethyl or propyl substituents; 1-octene; 1-octene with one or more methyl, ethyl or propyl substituents; 1-nonene; 1-nonene with one or more methyl, ethyl or propyl substituents; 1-decene; 1-decenewith one or more methyl, ethyl or propyl substituents;1-dodecene. Specifically, but without limitation, combinations of ethylene with one or more comonomers may include: ethylene / propylene, ethylene / butene, ethylene / 1-pentene, ethylene / 4-methyl-1-pentene, ethylene / 1- hexene, ethylene / 1-octene, ethylene / decene, ethylene / dodecene, ethylene / 1-hexene / 1-pentene, ethylene / 1- hexene / 4-methyl-1-pentene, ethylene / 1-hexene / 1- octene, ethylene / 1-hexene / decene, ethylene / 1-hexene / dodecene, ethylene / 1-octene / 1-pentene, ethylene / 1- octene / 4-methyl-1-pentene, ethylene / 1-octene / 1- hexene, ethylene / 1-octene / decene, ethylene / 1-octene / dodecene. In a particularly advantageous embodiment the one or more linear low density polyethylene polymers LLDPE, not coming from post-consumer recycled plastic material, are copolymers of ethylene with at least one α-olefin selected from 1-butene, 1-hexene, 1-octene and mixtures thereof. Advantageously, the one or more linear low density polyethylene polymers (LLDPE), not coming from post- consumer recycled plastic material, are characterized by having: i. a density between 0.8800 and 0.9210 g / cm3, saiddensity being measured in a gradient column according to standard ISO 1183-1:2019; ii. a melt flow rate (MFR) between 1.5 and 4.0 g / 10min, said index being determined at 190°C and with a weight of 2.16 kg according to standard ISO 1133- 1:2022. In a preferred embodiment the mixture of recycled plastic material (SRM), present in the polyethylene- based polymeric composition according to the invention, is characterized by: –a DSC curve having at least one peak between 60°and 130°C, and a fusion heat ΔH, between 100 and 200 J / g, measured between 20 and 145°C, said curve being obtained during the second heating in the following thermal treatment: a heating from 0 to 200°C at 20°C / min, an isotherm at 200°C for one minute, a cooling at 5°C / min up to 0°C, an isotherm at 0°C for one minute and a second heating from 0 to 200°C at 5°C / min; -a melt flow rate (MFR), between 1.0 and 5.5 g / 10min, preferably between 1.5 and 3.0 g / 10 min, said index being measured at 190°C and by applying a weight of 2.16 kg in accordance with standard ISO 1133-1:2022; -a density between 0.9000 and 0.9300 g / cm3,preferably between 0.9100 and 0.9270 g / cm3, measured in a gradient column in accordance with standard ISO 1183-1:2019; -a carbonyl index (CI), defined as the ratiobetween the intensities of the bands in the FTIR spectrum at 1740 and 2020 ± 1 cm-1, between 0.8 and 10, preferably between 0.9 and 5.0; said spectrum being recorded by analysing a film with thickness of 500 microns, obtained from the mixture of recycled plastic material (SRM) by moulding with a press preheated to 150°C; -an ash content, equal to at least 0.03%,preferably between 0.05 and 2.00%, still more preferably between 0.08 and 0.70%, said content being measured as residue of a thermal post- treatment of the recycled polymeric material (SRM) carried out at a temperature of 550 ±5°C; -a ratio between the concentration of tris(2,4-di-tert-butylphenyl) phosphite (additive A) and the concentration of tris(2,4-di-tert- butylphenyl) phosphite in oxidized form (additive B) less than 1, more preferably less than 0.7, said ratio being measured by a gas chromatography analysis carried out by using gas chromatography. The thermograms of said mixture of recycled plasticmaterial, measured by model DSC 2500 by TA Instruments,equipped with a RCS120 cooling system, highlight the presence of at least one calorimetric peak between 60 and 130°C, measured during the second heating cycle of the sample, carried out from 0 to 200°C, at 5°C / min, as described in the analysis section of the experimental part. Non-limiting examples of thermograms related to the recycled plastic mixtures used in the present invention are reported in figures 2, 3, 4. The existence in said thermograms of at least one calorimetric peak between 60 and 130°C is indicative of the presence of polyethylene-based polymeric material such as for example LDPE, LLDPE, HDPE and combinations thereof. The melt flow rate (MFR) and the density of the mixture of recycled plastic material were measured, as for the polyethylene-based composition in accordance with the respective ISO standards. The ash content, measured as thermal post-treatment residue at a temperature of about 550°C, is obtained as a result of a gravimetric analysis carried out on a weighed amount of sample of mixture of recycled plastic material, placed in a crucible placed inside a Milestone- PYRO microwave muffle; said muffle being set with the temperature ramp reported in the analysis section of the experimental part. The carbonyl index was determined, by infrared spectroscopy carried out, using the Bruker Equinox 55 spectrometer, on a film with thickness of 500 microns, obtained from the mixture of recycled plastic material, by moulding with a press preheated to 150°C. Said index, as widely described above, with reference to the polyethylene-based polymeric composition, is used to determine the degree of oxidation essentially of athermal nature of the mixture itself.The ratio between the concentration of tris(2,4-di- tert-butylphenyl) phosphite (additive A) and the concentration of tris(2,4-di-tert-butylphenyl) phosphite in oxidized form (additive B) was calculated by chromatographic gas analysis, using the TRACE GC ULTRA gas chromatograph (THERMO), equipped with an on-column injector, a flame ionization detector, a capillary column with Megalap stationary phase and by applying the following heating program: start at 80°C, increase at 17C / min up to 320°C, isotherm at 320°C for 10 minutes. First, the response factor of additive A was determined by analysing a solution of known concentration, as reported in the analysis section of the experimental part. Subsequently, the ratio between the concentration of A and B, present in the mixture of recycled plastic material, was calculated using the procedure reported in the analysis section of the experimental part. Said ratio is important in order to have indications on the thermalstability of the mixture of recycled plastic material.A non-limiting example of a mixture of recycled plastic material is given by the mixture obtained from the recycling process of waste coming from separate collection, in particular from the selection of domestic waste or waste coming from commercial and industrial activities. Specifically, the object of said collection and selection is waste consisting mainly of flexible post-consumer polyethylene packaging, defined according to standard D5491-08:2022. Anon-limiting example of a mixture of recycledplastic material consists of the mixtures referred to as SRM1, SRM2, SRM3, preferably SRM1 and SRM3. A non-limiting example of a recycling process consists of the following steps: -grinding of the selected waste;- washing with water at room temperature;- drying, in order to reduce the moisture contentresulting from washing. Subsequently, the recycled polymeric material can be transformed and used in flakes or melted in an extruder to obtain a product with homogeneous properties and subsequently granulated. A further object of the invention concerns a process for preparing the polyethylene-based polymeric composition, comprising the following steps: a. melting the recycled plastic mixture (SRM);b. filtering the material obtained in step (a) inthe molten state using a filter characterized by an aperture not higher than 99 microns, preferablybetween 50 and 89 microns; c. melting one or more linear low densitypolyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material; d. mixing the polymeric material obtained fromstep (b) with that obtained from step (c) in the molten state. In a preferred embodiment in step (d) of the synthesis process the weight ratios between the mixture of recycled plastic material (SRM) and the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, are between 20:80 and 90:10, preferably between 25:75 and 85:15, even more preferably they are about 60:40. A further object of the present invention refers to granules comprising the above-described polyethylene- based polymeric composition. The polymeric films, obtained from the polyethylene-based polymeric composition of the present invention or from the granules comprising said composition, are prepared by means of the process, reported below, which comprises the following steps: e. mixing the polymeric composition in the molten state, with a linear low density polyethylene polymer (LLDPE), such that the weight ratio between the polyethylene-based polymeric composition and said polymer is 1 to 1; f. extruding the mixture of step (e) in a cast film processing plant. If granules comprising the polyethylene-based polymeric composition are used in the process, step (e) is preceded by a step (e’) comprising melting said granules, which leads to obtaining the polymericcomposition in the molten state, used subsequently instep (e). Step (e) can then be carried out using both directly the polyethylene-based polymeric composition in the molten state, and the molten product obtained from step (s), if granules comprising said composition are used. In a particular embodiment the linear low density polyethylene polymer (LLDPE), used in step (e), consists of ethylene and hexene. In a particularly preferred embodiment, the linearlow density polyethylene polymer (LLDPE) used in step (e) is LLDPE-4. The mixture thus obtained in step (e) is processed in step (f) in a cast film processing machine. A non- limiting example of a machine used to produce polymeric films by cast film technology is reported in figure 1. The use of said machine is described in detail in example 1. Said machine, produced by Dolci Extrusion, consists of: a feeding zone (known in the art and not represented in figure 1); an extruder defined as "extruder barrel" with four zones operating at different temperatures, reported in table 1 and respectively called zone 1, 2, 3, 4; a zone defined as "neck", with thermal controlunit independent of the other zones; a zone defined as"black box", as a connection between the "neck" and the extrusion head (die head); a flat extrusion head (die head); a cooling roller (chill roll), known in the art and not represented in figure 1, which serves to solidify the molten polymer; a dragging and winding unit (known in the art and not represented in figure 1) for winding the film produced in the form of a reel. At the end of the process, a monolayer film with thickness between 20 and 100 microns and a useful width of about 500 mm is obtained. The film thus obtained is tested on a Pieri AVR201 pallet wrapper machine, equipped with a rotating arm that allows, thanks to two motorized rollers, which rotate at different speeds, to subject the film to a cold stretch and to wrap the stretched film on an artifact. The stretch, which takes place in the longitudinal direction with respect to the direction of extrusion of the film, is increased each time, in sucha way as to break the film, thus verifying which is themaximum extensibility of the produced film. The extensibility of the film (Ω) is then calculated by verifying the distance between two points of the film before stretching and after stretching. In particular,given L0 the distance between two points of the film before stretching and L1 the distance between the same two points following stretching, is defined by the following formula (I): Ω= (L1 – L0) / L0 (I)A film sample is defined as extensible to a given extensibility if in a set of twenty tests all conducted at that stretch value, the sample does not break more than twice: in this case it is said that the film passes the test (and it is therefore extensible) at that stretch value. The highest extensibility value at which the sample passes said test is defined as the maximum extensibility of the film (table 3). The compositions that generated films exhibiting amaximum extensibility higher than 500%, when testedaccording to the procedure described below in example 1, were subsequently studied to determine their rheological properties. In particular, for these compositions, elongational viscosity measurements over time were recorded. Said measurements were carried out, by means of the Ares LSII instrument, on a sample of polyethylene-basedpolymeric composition compression moulded in the form ofa rectangular bar at 170 C for about 5 minutes. Themeasurements were carried out after maintaining thesample at 130 C for 5 min and at a Hencky strain rate of1 s-1, as described in the experimental part (example 1). It is known that measurement of the elongational viscosity is critical to understanding the processing behaviour of the polyolefins. In particular, "strain hardening", defined starting from the elongational viscosity measured on the melt, is a desired property in film formation processes by cast film technology, since it stabilizes the film during the melt elongation phase. A continuous increase in the value of elongational viscosity over time is thereforeadvantageous in terms of the processability of thematerial in the production of films. In particular,if the values of elongational viscosity as a function of time are reported in a graph, a curve of increasingelongational viscosity over time, which at a certainpoint of the graph presents an inflection, isadvantageous. Said inflection point in fact outlinesa higher increase in the elongational viscosity overtime and determines a "strain hardening" behaviour of the polyethylene-based polymeric composition on which the measurements were taken. Graphs that report an increase in elongational viscosity over time that continues to grow until it tends to a limit value (plateau or horizontal asymptote value) are characteristic instead of polymers or polymeric compositions that do not have "strain hardening". Such evidence is reported in the literature, for example in "Effect of Rheological Strain Hardening on Extrusion Blown Film of Polyvinylidene Fluoride", July 2007, Journal of Plastic Film and Sheeting, 23(3), 203-219 (DOI: 10.1177 / 8756087907084987), "Transient elongational viscosity of LLDPE / LDPE blends and itsrelevance to bubble stability in the film blowing process", P. Micic, S. N. Bhattacharya, G. Field, first publication date 08 April 2004, (https: / / doi.org / 10.1002 / pen.10339), "Fundamentals of structure–property relationships in blown films of linear low density polyethylene / low density polyethylene blends", Journal of Plastic Film & Sheeting, Rajen M Patel, Teresa P Karjala, Nilesh R Savargaonkar, Philip Salibi, Lizhi Liu, 2019, (DOI: 10.1177 / 8756087919844303),"The Mechanism of Neck-in Phenomenon in Film Casting Process" Seiji Shiromoto, April 2014, International Polymer Processing Journal of the Polymer Processing Society, 29(2), page 197- 206 (DOI: 10.3139 / 217.2784). It should be pointed out, in fact, that LLDPE-4 and MIX-LL, used to produce the films of examples 2 and 11 (non-inventive) having a maximum extensibilityhigher than 500% (table 3), have an increase inelongational viscosity that tends to a finite limitvalue (plateau value) vs. time , without the presenceof an inflection, ("strain hardening"), as reported in the graphs of figure 6 and 11. On the other hand, in the films obtained from the polyethylene-based polymeric composition according to the invention, as reported in the curves of the graphs of figures 5, 8, 9, 10, 12, 13 respectively referred to examples 1, 7, 8, 10, 12, 13, a continuous increase in the elongational viscosity over time can be highlighted which at a certain moment has an inflection point. A further object of the invention is the use of the polymeric composition for the production, by cast film technology, of polymeric films, having a maximumextensibility higher than 500%, "strain hardening",and a thickness between 20 and 100 microns. Another object of the invention is the use of the granules comprising the polymeric composition for the production, by cast film technology, of polymeric films,having a maximum extensibility higher than 500%, "strainhardening", and a thickness between 20 and 100 microns. The following examples are provided merely to illustrate the present invention and should not be construed in a sense that would limit the scope of protection defined by the appended claims. Experimental part ANALYSIS and TESTING DSC ANALYSIS DSC analyses were carried out with the differential scanning calorimeter model DSC 2500 by TA Instruments equipped with a RCS120 cooling system. Calibration of the instrument was carried out withcertified Indium (melting temperature of Indium156.6 °C, melting enthalpy 28.7 J / g).In particular, the samples to be analysed wereprepared following the following procedure: 1 - 2 gramsof sample were placed between two sheets of polyesterand compression moulded at 170°C for about 30 seconds,so as to obtain a film with a uniform thickness of about500 microns. Subsequently, a piece of film weighing about2-5 mg was cut out and then placed in an aluminium sampleholder in order to be analysed. Thermograms were recorded by carrying out thefollowing heating ramps: a first heating ramp from 0 Cto 200 C at 20 C / min, an isotherm at 200 C for oneminute, a cooling ramp at 5 °C / min up to 0 C, an isothermat 0 C for one minute, and a second heating ramp from 0to 200 C at 5 C / min.Data analysis was carried out using Trios softwareversion 5.1 by TA instruments.NMR ANALYSISThe 13C-NMR spectra were recorded with a Brukerinstrument, operating at a proton frequency equal to 600 MHz (150 MHz for the13C NMR), equipped with CryoProbe,Cryoplatform Prodigy Unit and Avance Neo console. Theintegration software used to calculate peak areas was Mestre Nova. 30-50 mg of the sample to be analysed were crushed,weighed with analytical balance having accuracy of one tenth of a milligram and placed inside a 5 mm NMR tube (Wilmad NMR-Precision). Inside the tube, using a calibrated micropipette, 500 μL of a 0.025 M solution of CrIII(acetyl-acetonate)3 were added in 1,3,5- trichlorobenzene (reagent grade, Sigma-Aldrich). This corresponds to about 6 mg / mL of solution, as described by Zhou et al., Macromol. Symp. 2013, 330, p. 115-122. 80 μL of ortho-dichlorobenzene-d4 (98 atom% D, AcrosOrganics), required for the instrumental lock, wereadded to the solution. The mass concentration of thesample in the solution was about 5-6% w / w. The tube wasplaced in an upright position in an oven preheated to 150°C for a time varying from 4 h to 6 h, until the solidwas completely dissolved. The tube was then capped with a Teflon cap and inserted into the magnet with a probepreheated to 403 K. An inverted-gated pulse (zgig), 12kscans, SW: 60 ppm, offset: 30 ppm, TD: 32k, D1: 4s, was used. The most intense signal in the spectral windowused (0-60 ppm) was taken as a reference and set at 29.98ppm. The spectrum of the sample was characterized by thepresence of several signals, the most important of whichwere at 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C),11.19 ppm and 11.03 ppm (D). These resonances were integrated with MestreNovasoftware by carrying out a Lorentzian deconvolution of the signals. The integration values of the two resonancesat 11.19 ppm and 11.03 ppm were added in order to obtaina single value as both are related to methyl groups. By setting the sum of the integrations of the signals at 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppmand 11.03 ppm0 (D) to 100, the percentage distributionof the relative signals was calculated, in such a way asto obtain the value of A%, defined as the ratio between the area of signal A and the sum of the areas of signals A, B, C, D. DETERMINATION OF THE CARBONYL INDEX BY FT-IR FT-IR analyses were carried out with a Bruker Equinox 55 spectrometer, with spectral window 4000-400 cm-1at a resolution of 1 cm-1. For the purposes of thepresent invention, the limit of detectability wasassociated with the minimum measurable value of theabsorbance of the vibrational peak at 1740 cm-1. Saidminimum measurable value was equal to 0.001. The FT-IR spectra were acquired in transmission mode on films of about 500 microns thickness obtained by moulding about 0.5 grams of the sample to be analysed with a press preheated to 150°C. DETERMINATION OF ASH CONTENT The ash content measured as thermal post-treatmentresidue at about 550°C was the result of athermogravimetric analysis carried out by weighing about8 g of sample to be analysed in a crucible, consisting of refractory material. The crucible was previouslytared with an analytical balance having accuracy of onetenth of milligram. The crucible was placed in Milestone-PYRO microwavemuffle set with the following temperature profile: -ramp from 25°C to 550°C over 7h;- maintenance at 550 C for 10h;- back to 25 C for 5h.Once cooled, the crucible containing the residuewas weighed on an analytical balance with accuracy ofone tenth of a milligram, thus computing the percentagecontent of ash resulting from the thermal treatment. FILTRATION TEST The filtration test consisted of the extrusion ofa sample of polyethylene-based polymeric composition in a single screw extruder, characterized by a diameter of about 30 mm, and a length / diameter ratio equal to 28,and comprising a filter characterized by an apertureequal to 89 microns, placed upstream of the die. The speed of the extruder screw was regulated so asto ensure the mass flow rate was maintained to 5 ±0.5kg / h while the temperature profile was set to 170°C(hopper)- 200°C (extruder barrels) - 210°C (die).The following quantities were defined and measured:- "ΔPin", which was the difference between the pressureupstream the filter and the pressure downstream thefilter recorded after 5 minutes of the test (i.e., after5 minutes after the extruder started);- "ΔPfin", which was the difference between the pressureupstream the filter and the pressure downstream the filter recorded after 60 minutes of the test.The sample passed the filter test if the ΔPfin was lessthan 2*ΔPin.DETERMINATION OF THE MELT FLOW RATE (MFR)The melt flow rates were measured according tostandard ISO 1133-1:2022 at 190°C and using a weight of 2.16 Kg. DETERMINATION OF THE DENSITY Densities were measured by means of a gradientcolumn according to standard ISO 1183-1:2019.DETERMINATION OF THE RATIO VALUE OF THE CONCENTRATION OFTRIS(2,4-DI-TERT-BUTYLPHENYL) PHOSPHITE (ADDITIVE A) ANDTHE CONCENTRATION OF TRIS(2,4-DI-TERT-BUTYLPHENYL)PHOSPHITE IN OXIDIZED FORM (ADDITIVE B) The determination of the ratio between the concentration of tris(2,4-di-tert-butylphenyl) phosphite, (additive A), CAS number 31570-04-4, and the concentration of tris(2,4-di-tert-butylphenyl)phosphite in oxidized form (additive B) was measured viagas chromatography. Aresponse factor fA was calculated starting from a solution of known concentration of additive A. In particular, a solution in cyclohexane / isopropanol was prepared, in a 50 / 50 w / w mixture, containing 100 ppm of additive A and 100 ppm of methyl stearate. The solution thus obtained was analysed using the GCTRACE GC ULTRA equipment (THERMO), equipped with on- column injector, flame ionisation detector (FID detector, TRIPLUS-RSH(THERMO) autosampler. Below are reported the instrumental parameters used for the analysis:- Capillary column: Stationary phase: Megalap, length30 m, inner diameter 0.32 mm, thickness 0.1 µm;- Carrier gas: He, 60KPa, "constant pressure" mode;- Injector type: on-column;- Detector temperature: 320°C;- Heating program: start at 80°C, increase at17°C / min up to 320°C, isotherm at 320°C for 10 minutes;- Injection volume: 1 µl.The response factor fA was defined as follows:fA = ([cA] / [ISTD]) / (Aa / AIstd) wherein: [cA] = concentration of additive A; [ISTD] = methyl stearate concentration (theinternal standard); Aa = Peak area of additive A (retention time 15.2 min) AIstd = Peak area of methyl stearate Subsequently, about 3 grams of the SRM sample containing the additive A and the additive B werecompression moulded in the form of films about 500microns thick and cut out in the form of squares of about 1 cm2in area. 15 ml of a 50 / 50 w / w cyclohexane / isopropyl alcohol mixture and 1 ml of an"internal standard solution" were mixed together. This"internal standard solution" consisted of 100 ml of a50 / 50 w / w cyclohexane / isopropyl alcohol mixture and about 0.1 g of methyl stearate. Approximately 1.5 gramsof the cut compression moulded SRM sample (Ws)previously obtained were weighed and placed in contactwith the 15+1=16 ml of the previously preparedsolution. Wis was defined as the weight in µg of themethyl stearate used. The composition thus obtained was placed in a stirred container of the "Green Chem" type to carry out the extraction using the MARS 6 microwaveextractor (CEM). The container was subjected to athermal cycle consisting of a ramp from T0=25°C to T1=85°C over 5 minutes, subsequent isothermal holding at T1 for 35 minutes and subsequent cooling from T1 to T0 over 15 minutes. The power provided by the extractorwas 250 W. The sample thus obtained was filtered toseparate traces of solid material from the liquid phaseand the latter was also analysed through the GC TRACEGC ULTRA equipment (THERMO), equipped with on-column injector, flame ionization detector (FID detector), TRIPLUS RSH autosampler (THERMO), according to the same instrument parameters defined above. The concentration of additive A (xA) and additiveB (xB) in the sample, expressed in ppm, was thencalculated as follows: xA= (Aa * Wis) / (AIstd * fA* Ws) xB= (Ab * Wis) / (AIstd * fA* Ws) wherein: Ab = Peak area of additive B (retention time 16.5 min). PREPARATION AND CHARACTERIZATION OF THE RAW MATERIALS USED IN EXAMPLES 1 TO 12: -PREPARATION and CHARACTERIZATION OF SRM-1The mixture of recycled material also calledsecondary raw material SRM-1, based on polyethylene, wasobtained from the recycling process of waste coming fromthe separate collection, and the sorting of the wasteproduced by commercial and industrial activities. Inparticular, the material of said collection and sortingwas waste, as defined by ASTM norm D5491-08:2022,consisting mainly of flexible post-consumer polyethylene packaging. The material collected and sorted was subjected toa grinding process. Subsequently the ground material was washed with water at room temperature and dried in air flow at about 50-60°C in order to reduce the moisture content resulting from washing. The dried material was then melted in a single screw extruder to obtain a product with homogeneous properties to be sent to the granulator. SRM-1 granules were thus obtained. They were analysed using the techniques described above, reported in the analysis and testing section of the experimental part. They showed: -a DSC thermogram recorded during the secondheating cycle as reported in figure 2. The thermogram recorded the presence of a melting peakat 110.4°C and a second peak at 122.1°C. The melting enthalpy obtained from the sum of the areas of said peaks was 138.93 J / g. The presence of twoneighbouring melting peaks in the thermogram indicated the presence in SRM-1 of polyethyleneobtained through different synthesis technologies (e.g. synthesis by radical processes and synthesis by catalytic processes). -a MFR value (190°C, 2.16 kg), in accordancewith standard ISO 1133-1:2022, equal to 2.4 g / 10 min; -a density measured at 23°C, in accordance withstandard ISO 1183-1:2019, of 0.9220 g / cm3;- a carbonyl index (CI) equal to 1.03;- an ash value at 550±5°C equal to 0.08%;- a ratio value between the concentration oftris(2,4-di-tert-butylphenyl) phosphite (additiveA) and the concentration of tris(2,4-di-tert- butylphenyl) phosphite in oxidized form (additive B) of less than 0.3. -PREPARATION and CHARACTERIZATION OF SRM-2The mixture of recycled material also calledsecondary raw material SRM-2, based on polyethylene, wasobtained with a process similar to that used to produce SRM-1. SRM-2 was analysed with the techniques described above, reported in the analysis and testing section of the experimental part. It showed: -a DSC thermogram recorded during the second heatingcycle as reported in figure 3. The thermogram shows the presence of two melting peaks, at 109.7°C andat 122.9°C. The total melting enthalpy measured during the second heating was equal to 168.51 J / g.- a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 0.8 g / 10 min; -a density measured at 23°C, in accordance withstandard ISO 1183-1:2019, equal to 0.9279 g / cm3;- a carbonyl index (CI) equal to 3.6;- an ash value at 550±5 °C equal to 0.40%;- a ratio value between the concentration oftris(2,4-di-tert-butylphenyl) phosphite (additive A) and the concentration of tris(2,4-di-tert- butylphenyl) phosphite in oxidized form (additive B) of less than 0.2. -PREPARATION and CHARACTERIZATION OF SRM-3The mixture of recycled material also calledsecondary raw material SRM-3 based on polyethylene wasproduced from the commercial products DRK® (product marketed by the company DERIBLOK), PO70U® (product marketed by the company PROPAC) and XMAX® (product marketed by the company NOLANPLASTICA). DRK®, PO70U® and XMAX® have been identified as representative of flexible polyethylene post-consumer waste, as they are used in both the industrial and domestic packaging sectors. SRM-3 was produced as follows: a first DRK® sample, a second PO70U® sample and a third XMAX® sample were individually subjected to the following steps: -grinding;- washing with water at room temperature;- drying at 60°C, in order to reduce the moisturecontent resulting from washing. After drying, flakes of dried material were obtained. Subsequently, a mixture composed of 60 parts by weight of the dried DRK®-based sample, 20 parts by weight of the dried PO70U®-based sample and 20 parts by weightof the XMAX®-based sample was prepared by means of a drymixing process carried out at room temperature. The mixture thus obtained, after addition with 1PHR of POLYBATCH LCC 70 NATURAL masterbatch producedby LyondellBasell, was extruded in order to obtain afinal product with homogeneous properties. The POLYBATCH LCC 70 NATURAL masterbatch is acompound containing CaCO3 and its use in this mixtureis aimed to introduce mineral fillers to simulate the possible contaminations present in the materials coming from the recycling of plastic waste. The extruded product was subsequently subjectedto granulation by means of spaghetti cutting with acutter (“strand pelletizer”). The SRM-3 granules were subsequently analysed, using the methods reported in the analysis and testing section of the experimental part. They showed: -a DSC thermogram recorded during the secondheating cycle as reported in figure 4. The thermogram showed the presence of two meltingpeaks at 109.3°C and at 122.1°C. The total melting enthalpy measured during the second heating was equal to 139.48 J / g. -a MFR value (190°C, 2.16 kg), in accordancewith standard ISO 1133-1:2022, equal to 1.9 g / 10min; -a density measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9210 g / cm3; -a carbonyl index (CI) equal to 2.9;- an ash value at 550±5°C equal to 0.60%;- a ratio value between the concentration oftris(2,4-di-tert-butylphenyl) phosphite (additive A) and the concentration of tris(2,4-di-tert- butylphenyl) phosphite in oxidized form (additive B) of less than 0.4. -CHARACTERIZATION OF LLDPE-1LLDPE-1 was a polyethylene containing 13% w / w ofhexene (i.e a copolymer ethylene-hexene, with 13% w / w ofhexene), measured with the 13C NMR technique inaccordance with ASTM D5017-17. In addition, LLDPE-1showed the following characteristics, measured inaccordance with the procedures and the techniques reported in the analysis and testing section of the experimental part: -a MFR value (190 C, 2.16 kg), in accordancewith standard ISO 1133-1:2022, equal to 2.5 g / 10min; -a density measured at 23 C in accordance withstandard ISO 1183-1:2019, equal to 0.9160 g / cm3; -an ash value at 550±5 C not measurable (N / A).- CHARACTERIZATION OF LLDPE-2LLDPE-2 was a polyethylene containing 10% w / w butene(i.e a copolymer ethylene-butene, with 10% w / w ofbutene), measured with 13C NMR technique in accordancewith ASTM D5017-17. In addition, LLDPE-2 showed thefollowing characteristics, measured in accordance with the procedures and the techniques reported in the analysis and testing section of the experimental part: -a MFR value (190 C, 2.16 kg), in accordancewith standard ISO 1133-1:2022, equal to 26.0 g / 10min; -a density measured at 23 C, in accordance withstandard ISO 1183-1:2019, equal to 0.9220 g / cm3;- an ash value at 550±5 °C not measurable (N / A).- CHARACTERIZATION OF LLDPE-3LLDPE-3 was a polyethylene containing 16% w / w ofoctene (i.e a copolymer ethylene-octene, with 16% w / w ofoctene), measured with the 13C NMR technique inaccordance with ASTM procedure D5017-17. In addition,LLDPE-3 showed the following characteristics, measuredin accordance with the procedures and the techniques reported in the analysis and testing section of the experimental part: -a MFR value (190 C, 2.16 kg), in accordancewith standard ISO 1133-1:2022, equal to 3.8 g / 10 min; -a density measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9165 g / cm3; -an ash value at 550±5°C not measurable (N / A).- LLDPE-4 CHARACTERIZATIONLLDPE-4 was a polyethylene containing 11% w / w ofhexene (i.e a copolymer ethylene-hexene, with 11% w / w ofhexene). In addition, LLDPE-4 showed the followingcharacteristics, measured in accordance with the procedures and the techniques reported in the analysis and testing section of the experimental part: -a MFR value (190°C, 2.16 kg), in accordancewith standard ISO 1133-1:2022, equal to 3.2 g / 10 min; -a density measured at 23°C, in accordance withstandard ISO 1183-1:2019, equal to 0.9220 g / cm3;- an ash value at 550±5°C not measurable (N / A).EXAMPLE 1 (INVENTIVE): Preparation of MIX-1 and of the polymeric film obtained using MIX-1 Raw materials used: -SRM-1 granules -LLDPE-1 SRM-1 in granules were melted by an extruder,similar to that used for the filter test, and filteredon a mesh filter having a free aperture of 89 microns.The product thus obtained was mixed in a twin-screw extruder with LLDPE-1 with the following weight ratio: 60 of SRM-1 and 40 of LLDPE-1. The twin-screw extruderused was a Coperion ZSK40 extruder with a diameter (D)equal to 40 mm, and a ratio length (L) to diameter (D) equal to 38, with the following characteristics: -temperature profile: 160 (hopper)-180-200-200-200-210 (die)°C; -screw speed: 200 rpm; -total mass flow rate: 30 kg / h. A product called MIX-1 was obtained from the extrusion, characterised by: -a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm are added in order to obtain a single value and by setting the sum of the integrations of the signals described above to 100, the distribution reported below was obtained:1.8% (A%) 12.8% (B%) 64.2% (C%) 21.2% (D%);- a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.4 g / 10 min;- a density, measured at 23 C in accordance withstandard ISO 1183-1:2019, equal to 0.9183 g / cm3; -passing the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550± 5°C, equal to0.05%. -a carbonyl index (CI) value equal to 0.92.MIX-1 was further subjected to an elongational viscosity test to study its rheological behaviour. Whensubjected to an elongational viscosity test, MIX-1showed the rheological behaviour as reported in the plotof figure 5. In fact, the plot of figure 5 shows thatthe value of the elongational viscosity increasedsteadily over time and presents an inflection point("strain hardening") under the test conditions; thisincrease in viscosity is advantageous in terms of theprocessability of the material in the film preparation process by cast film technology. MIX-1 was subsequently dry mixed with LLDPE-4 in1:1 weight ratio.The mixture was then fed into a flat-head machineto produce polymeric films produced by Dolci Extrusion.A non-limiting example of said machine is reported infigure 1. The machine of figure 1 was characterized by:- an extruder with a diameter equal to 55 mm and alength / diameter ratio (L / D) equal to 30; -a flat die head with width equal to 900 mm, havinga thickness value of the "gap" (die gap) through which the polymer is extruded equal to 2 mm; -a cooling / take-up unit composed by a primary chillroll with a diameter equal to 600 mm and a secondary chill roll with a diameter equal to 250 mm, both fed by a dedicated cooling unit. A non-limiting example of the main workingparameters set in the different zones of the machine toobtain the polymeric films is reported in table 1. Working parameters Temp. Zone 1 (°C) 230Temp. Zone 2 (°C) 240Temp. Zone 3 (°C) 245 Working parameters Temp. Zone 4 (°C) 250Temp. Neck (°C) 250Temp. black box (°C) 250Temp. Die Head (°C) 250Temp. chill roll (°C) 20Mass flow rate (kg / h) 50Take-up speed (m / min) 40Freezing line / die distance (mm) 200Table 1 A polymeric film with thickness of 23 microns wasthus obtained, which had the following finalcomposition: 30% SRM-1 + 20% LLDPE-1 + 50% LLDPE-4. Subsequently, the polymeric film was tested on a Pieri AVR201 pallet wrapper machine to measure the maximum extensibility thereof. The pallet wrappermachine was equipped with a rotating arm. By means oftwo motorized rollers, which rotate at different speeds,the rotating arm let the film be subjected to a specifiedcold stretch, before being placed on the item to bewound. The stretch is set in such a way as to break thefilm. Aset of 20 stretching tests was carried out.A film sample was defined to be extensible to agiven extensibility if, in a set of twenty tests allconducted at that stretch value, the sample does notbreak more than twice: in this case the film passed thetest (and it is therefore extensible) at that stretchvalue. Among the extensibility tests carried out atvarious stretch values. The highest extensibility valueat which the sample passed this test was defined as themaximum extensibility of the film. The maximum extensibility value obtained from the film containingMIX-1 is reported in table 3.Subsequently, since the film containing MIX-1showed a maximum extensibility value higher than 500%,the elongational viscosity measurements were carried outon MIX-1. Said measurements were carried out using theAres LS II instrument on a sample of MIX-1 compressionmoulded in the form of a rectangular bar at 170°C forabout 5 minutes. The test temperature was set at 130°C while the strain rate (Hencky strain rate) was set equal to 1 s-1. At the end of the test, the measurements of the elongational viscosity of the MIX-1 sample as a functionof time were reported in a chart (figure 5).The graph of figure 5 shows that MIX-1 had "strainhardening". EXAMPLE 2 (NON-INVENTIVE) Preparation of polymeric film obtained using LLDPE-4 A LLDPE-4 film with thickness of 23 microns was produced as described in Example 1, by feeding only LLDPE-4 granules to the flat-head machine to produce polymeric films produced by Dolci Extrusion described in example 1. The maximum extensibility of the film was verifiedaccording to the procedure reported in example 1. Thevalue obtained, higher than 500%, is reported in table3. The final composition of the tested film was 100%LLDPE-4. When subjected to the elongational viscosity test,described in example 1, LLDPE-4 showed the rheologicalbehaviour, reported in the chart of figure 6.Figure 7 reports the comparison with the behaviour shown by MIX-1. Differently from MIX-1, the measurementof the elongational viscosity, did not show the presenceof an inflection point in the test conditions ("strain hardening"); this behaviour is penalising in terms of the processability of the material in filming processes, as described above. LLDPE-4 had the characteristics reported in thesection of the experimental part concerning the preparation and characterization of the raw materials used in examples 1 to 13. In addition, the13C-NMR spectrum of the LLDPE-4 sample, analysed following what is reported in the analysis section of the experimental part, was characterized by the presence of the following signals of interest: 32.16 ppm(B), 23.37 ppm (C). The presence of resonances at chemical shift values similar to thoseof signals A and D was not detected.By setting the sum of the integrations of the signals described above to 100%, the distribution reported below was obtained: 0% (A%), 1.6% (B%), 98.4% (C%) and 0% (D%). EXAMPLE 3 (NON-INVENTIVE): Preparation of MIX-LLDPE-4 and of the polymeric film obtained using MIX-LLDPE-4 Example 1 was repeated using LLDPE-4 instead of LLDPE-1, with an SRM-1 / LLDPE-4 ratio equal to 60:40. The product thus obtained, called MIX-LLDPE-4, was characterized by: -a 13C NMR spectrum comprising the followingsignals at 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value.By setting the sum of the integrations of thesignals described above to 100, the distribution reported below was obtained: 1.8% (A%), 12.5% (B%)64.3% (C%) and 21.4% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.4 g / 10 min; -a density, measured at 23 °C in accordance withstandard ISO 1183-1:2019, equal to 0.9220 g / cm3. -passing the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to 0.05%. -a carbonyl index (CI) value equal to 0.43.The product thus obtained was subsequently fed, in a 1 to 1 mixture by weight with LLDPE-4, to a flat-headtransformation machine to produce polymeric films produced by Dolci Extrusion, according to the procedure described in example 1, obtaining a film with thickness of 23 microns. The maximum extensibility of the film was verified according to the procedure described above in example 1. The value obtained, less than 500%, is reported in table 3. The final composition of the tested film was: 30% SRM-1 + 70% LLDPE-4.EXAMPLE 4 (NON-INVENTIVE): Preparation of MIX-2 and ofthe polymeric film obtained using MIX-2. Example 1 was repeated using LLDPE-2 instead of LLDPE-1, obtaining the product called MIX-2, characterized by: -a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value.By setting the sum of the integrations of the signals described above to 100, the distribution reported below was obtained: 1.7% (A%), 12.7% (B%),24.1% (C%), 61.5% (D%). -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 5.6 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9220 g / cm3; -passing the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to 0.05%. -a carbonyl index (CI) value equal to 0.66.Subsequently, the flat-head transformation machinefrom Dolci Extrusion was fed with a mixture composed of MIX-2 and LLDPE-4 in a ratio of 1 to 1 by weight,according to the procedure described in example 1,obtaining a film with thickness of 23 microns. The final composition of the tested film was: 30% SRM-1 + 20% LLDPE-2 + 50% LLDPE-4. The maximum extensibility of the film was verified according to the procedure described in example 1. The value obtained, less than 500%, is reported in table 3. EXAMPLE 5 (NON-INVENTIVE): Preparation of MIX-1 NF and of the polymeric film obtained using MIX-1 NF Example 1 was repeated with the only difference ofnot subjecting SRM-1 to filtration, obtaining thecomposition called MIX-1 NF, characterized by: -a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integrationvalues of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value.By setting the sum of the integrations of the signals described above to 100, the distributionreported below was obtained: 1.8% (A%), 12.7% (B%), 64.4% (C%) and 21.1% (D%). -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.4 g / 10 min;- a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9183 g / cm3; -not passing the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to0.05%. -a carbonyl index (CI) value equal to 0.64.MIX-1 NF did not pass the filtration test, asdescribed above. MIX-1 NF was subsequently fed, in a 1 to 1 mixturewith LLDPE-4, to the flat-head transformation machinefrom Dolci Extrusion, according to the procedure described in example 1, obtaining a film with thickness of 23 microns. The final composition of the tested film was: 30% SRM-1 + 20% LLDPE-1 + 50% LLDPE-4. The maximum extensibility of the film was verified according to the procedure described previously and reported in example 1. The value obtained, less than 500%, is reported in table 3. EXAMPLE 6 (NON-INVENTIVE): Preparation of MIX-3 and of the polymeric film obtained using MIX-3. Example 1 was repeated using SRM-2 instead of SRM- 1, obtaining the product called MIX-3, characterized by: -a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value. By setting the sum of the integrations of the signals described above to 100, the % distribution reported below was obtained: 4.7% (A%), 8.0% (B%),64.1% (C%) and 23.2% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 1.4 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9209 g / cm3; -passing the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550± 5°C, equal to0.30%. -a carbonyl index (CI) value equal to 2.18.MIX-3 was subsequently fed, in a mixture with LLDPE-4 in a ratio of 1 to 1 by weight, to the flat-headtransformation machine produced by Dolci Extrusion,according to the procedure described in example 1, obtaining a film with thickness of 23 microns. The final composition of the tested film was: 30% SRM-2 + 20% LLDPE-1 + 50% LLDPE-4. The maximum extensibility of the film was verified according to the procedure described above and reported in example 1. The value obtained, less than 500%, is reported in table 3. EXAMPLE 7 (INVENTIVE): Preparation of MIX-4 and of the polymeric film obtained using MIX-4 Example 1 was repeated with the only difference that SRM-1 was mixed with LLDPE-1 in weight ratio 80 (SRM- 1):20 (LLDPE-1) obtaining the product called MIX-4, characterized by: -a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain asingle value. By setting the sum of the integrations of the signals described above to 100, the % distribution reported below was obtained: 2.4% (A%) 16.1% (B%) 53.3% (C%) and 28.2% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 1.8 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9172 g / cm3. -passing the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to 0.07%. -a carbonyl index (CI) value equal to 1.67.MIX-4 was subsequently fed, in a mixture with LLDPE-4 in a ratio of 1 to 1 by weight, to the flat-headtransformation machine produced by Dolci Extrusion,according to the procedure described in example 1, obtaining a film with thickness of 23 microns. The final composition of the tested film was: 40% SRM-1 + 10% LLDPE-1 + 50% LLDPE-4. The maximum extensibility of the film was verifiedaccording to the procedure previously described andreported in example 1. The value obtained is reported in table 3. Figure 8 reports the behaviour shown by MIX-4 in anelongational viscosity test compared with LLDPE 4. Theelongational viscosity measurement showed an increase inviscosity over time, with an oblique inflection point ("strain hardening"), under the test conditions; thisincrease in viscosity is advantageous in terms of theprocessability of the material in filming processes. EXAMPLE 8 (INVENTIVE): Preparation of MIX-5 and of the polymeric film obtained using MIX-5 Example 1 was repeated with the only difference that MIX 1 was mixed with LLDPE-1 in the following weightratio: 30 of SRM-1: 70 of LLDPE-1. This resulted in theproduct called MIX-5. MIX 5 was characterised by:- a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain asingle value. By setting the sum of theintegrations of the signals described above to 100, the % distribution reported below was obtained:0.8% (A%), 6.3% (B%), 81.8% (C%) and 11.1% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.8 g / 10 min;- a density, measured at 23°C in accordance withstandard ISO 1183-1:2019. -passing the filtration test, equal to 0.9203g / cm3; -an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to 0.07%; -a carbonyl index (CI) value equal to 0.83.MIX-5 was subsequently fed, in a 1 to 1 mixture with LLDPE-4, to the flat-head transformation machinefrom Dolci Extrusion, according to the proceduredescribed in example 1, obtaining a film with thickness of 23 microns. The final composition of the tested film was: 15% SRM-1 + 35% LLDPE-1 + 50% LLDPE-4. The maximum extensibility of the film was verified according to the procedure described in example 1 and the value obtained is reported in table 3. Figure 9 reports the behaviour shown by MIX-5 in an elongational viscosity test compared to LLDPE-4. Theelongational viscosity measurement showed a constantincrease in viscosity over time, with an inflection point("strain hardening"), under the test conditions; thisincrease in viscosity is advantageous in terms of theprocessability of the material in filming processes. EXAMPLE 9 (NON-INVENTIVE): Preparation of MIX-6 and of the polymeric film obtained using MIX-6 Example 4 was repeated with the only difference that SRM 1 was mixed with LLDPE-2 in the weight ratio 30 SRM- 1:70 LLDPE-2, obtaining the product called MIX-6, characterized by: -a 13C NMR spectrum comprising the followingsignals at: 32.62 ppm (A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain asingle value. By setting the sum of theintegrations of the signals described above to100, the percentage distribution reported below was obtained: 0.9% (A%), 6.4% (B%), 12.4% (C%)80.3% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 6.5 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9221 g / cm3; -passes the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to0.03%; -a carbonyl index (CI) value equal to 0.30.MIX-6 was subsequently fed, in a mixture with LLDPE- 4 in a ratio of 1 to 1 by weight, to a flat-headtransformation machine produced by Dolci Extrusion,according to the procedure described in example 1. The final composition of the tested film, with thickness of 23 microns, was: 15% SRM-1 + 35% LLDPE-2 + 50% LLDPE-4. The maximum extensibility of the film was verified according to the procedure previously described and reported in example 1. The value obtained, less than 500%, is reported in table 3. EXAMPLE 10 (INVENTIVE): Preparation of MIX-7 and of the polymeric film obtained using MIX-7. Example 1 was repeated using SRM-3 instead of SRM- 1, obtaining the product called MIX-7, characterized by: -a 13C NMR spectrum comprising the followingsignals at: A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value. By settingthe sum of the integrations of the signals described above to 100, the percentage distribution reported below was obtained: 1.7%(A%), 6.6% (B%), 78.6% (C%), 13.1% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.3 g / 10 min; -a density, measured at 23 °C in accordance withstandard ISO 1183-1:2019, equal to 0.9164 g / cm3; -passes the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to0.18%; -a carbonyl index (CI) value equal to 1.71.MIX-7 was subsequently fed, in a mixture with LLDPE- 4 in a ratio of 1 to 1 by weight, to a flat-headtransformation machine produced by Dolci Extrusion,according to the procedure described in example 1.The final composition of the tested film, with thickness of 23 microns, was: 30% SRM-3 + 20% LLDPE-1 + 50% LLDPE-4. The maximum extensibility of the film was verified according to the procedure previously described in example 1 and is reported in table 3. Figure 10 reports the behaviour shown by MIX-7 inan elongational viscosity test compared to LLDPE-4. Theelongational viscosity measurement showed a constantincrease in viscosity over time, with the presence of an inflection point ("strain hardening"), under the test conditions; this increase in viscosity is advantageous in terms of the processability of the material in filming processes, as described above. EXAMPLE 11 (NON-INVENTIVE): Preparation of MIX-LL and of the polymeric film obtained using MIX-LL. Example 1 was repeated using LLDPE-4 instead of SRM- 1, obtaining the product called MIX-LL, characterized by: -a 13C NMR spectrum comprising the followingsignals at: A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value. By setting the sum of the integrations of the signals described above to 100, the percentage distribution reported below was obtained: 0% (A%),2.6% (B%), 97.4% (C%), 0% (D%);- a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.6 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9170 g / cm3. -passes the filtration test;- an imponderable ash content (N / A), measured asresidue of a thermal post-treatment of the polymeric composition at a temperature of 550±5°C; -a carbonyl index (CI) value equal to 0.01.MIX-LL was subsequently fed, in a 1 to 1 mixturewith LLDPE-4, to the flat-head transformation machinefrom Dolci Extrusion, according to the procedure described in example 1, obtaining a film with thickness of 23 microns. The final composition of the tested film was: 20% LLDPE-1 + 80% LLDPE-4. The maximum extensibility of the film was verified according to the procedure previously described in example 1 and is reported in table 3. Figure 11 reports the behaviour shown by MIX-LL whensubjected to an elongational viscosity test. As can be easily deduced from the graph of figure 11, the measurement of elongational viscosity over time, unlike what is shown in the inventive examples described, doesnot highlight the presence of any inflection point("strain hardening") under the test conditions; this behaviour is penalising in terms of the processability of the material in filming processes, as described above. EXAMPLE 12 (INVENTIVE): Preparation of MIX-8 and of the polymeric film obtained using MIX-8 Example 1 was repeated using LLDPE-3 instead ofLLDPE-1. This resulted in the product called MIX-8.Mix 8 was characterized by:- a 13C NMR spectrum comprising the followingsignals at: A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value. By settingthe sum of the integrations of the signals described above to 100, the percentage distribution reported below is obtained: 1.6% (A%), 60.8% (B%), 17.7% (C%), 19.9% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.6 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9199 g / cm3; -passes the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymericcomposition at a temperature of 550±5°C, equal to 0.09%; -a carbonyl index (CI) value equal to 0.82.MIX-8 was subsequently fed, in a 1 to 1 mixturewith LLDPE-4, to the flat-head transformation machinefrom Dolci Extrusion, according to the proceduredescribed in example 1, obtaining a film with thickness of 23 microns. The final composition of the tested film was: 30% SRM-1 + 20% LLDPE-3 + 50% LLDPE-4. The maximum extensibility of the film was verifiedaccording to the procedure described for example 1 andits value is reported in table 3. Figure 12 reports the behaviour shown by MIX-8 in the elongational viscosity test compared to LLDPE-4 (example 2). The elongational viscosity measurementshows a constant increase in viscosity over time, withthe presence of an inflection point ("strain hardening"), under the test conditions; this increase inviscosity is advantageous in terms of the processabilityof the material in filming processes, as described above. EXAMPLE 13 (INVENTIVE) Preparation of MIX-9 and of the polymeric film obtained using MIX-9 Example 1 was repeated using a mixture of LLDPE-1 and LLDPE-3 (50 / 50 w / w) instead of LLDPE-1, obtaining the product called MIX-9, characterized by: -a 13C NMR spectrum comprising the followingsignals at: A), 32.16 ppm (B), 23.37 ppm (C), 11.19 ppm and 11.03 ppm (D); the integration values of the two resonances at 11.19 ppm and 11.03 ppm were added in order to obtain a single value. By setting the sum of the integrations of the signals described above to 100, the percentage distribution reported below is obtained: 2.1% (A%), 36.9% (B%), 40.4% (C%), 20.6% (D%); -a MFR value (190°C, 2.16 kg), in accordance withstandard ISO 1133-1:2022, equal to 2.4 g / 10 min; -a density, measured at 23°C in accordance withstandard ISO 1183-1:2019, equal to 0.9192 g / cm3; -passes the filtration test;- an ash content, measured as a residue of athermal post-treatment of the polymeric composition at a temperature of 550±5°C, equal to 0.08%; -a carbonyl index (CI) value equal to 0.83.MIX-9 was subsequently fed, in a 1 to 1 mixture by weight with LLDPE-4, to a flat-head transformationmachine from Dolci Extrusion, according to the proceduredescribed in example 1, obtaining a film thickness of 23 microns. The final composition of the tested film was:30% SRM-1 + 10% LLDPE-1 + 10% LLDPE-3 + 50% LLDPE- 4. The maximum extensibility of the film was verified according to the procedure described above and its value is reported in table 3. Figure 13 reports the behaviour shown by MIX-9 in the elongational viscosity test compared to LLDPE-4 (example 2). The elongational viscosity measurementshows a constant increase in viscosity over time, withthe presence of an inflection point ("strain hardening"), under the test conditions; this increase inviscosity is advantageous in terms of the processabilityof the material in filming processes, as described above. Below the summary table 2, containing the characteristics of the polymeric compositions obtainedin the examples described above, and table 3, reportingin the last column the maximum extensibility value of the films obtained from the various polymeric compositions, are reported.Example ComponentComposi Component Density Ash Filter"A"tion MFRCI1 2 test NMR name [g / 10 [g / cm] [%] [%] min] 1 SRM-1 LLDPE-1 MIX-1 2.4 0.9183 0.05 yes 0.92 1.8inventive 60% 40& 2 LLDPE-4 non- _LLDPE-4 3.2 0.9220 N / A yes 0.01 0100% inventive 3 SRM-1 LLDPE-4 MIX- non-2.4 0.9220 0.05 yes 0.43 1.840% LLDPE-4 inventive 60% 4 SRM-1 LLDPE-2 non-MIX-2 5.6 0.9220 0.05 yes 0.66 1.760% 40% inventive 5 SRM-1 LLDPE-1 MIX-1- non-2.4 0.9183 0.05 no 0.64 1.860% 40% nf inventive 6 SRM-2 LLDPE-1 non-MIX-3 1.4 0.9209 0.30 yes 2.18 4.760% 40% inventive 7 SRM-1 LLDPE-1 MIX-4 1.8 0.9172 0.07 yes 1.67 2.4inventive 80% 20% 8 SRM-1 LLDPE-1 MIX-5 2.8 0.9203 0.07 yes 0.83 0.8inventive 30% 70% 9 SRM-1 LLDPE-2 non-MIX-6 6.5 0.9221 0.03 yes 0.30 0.930% 70% inventive 10 SRM-3 LLDPE-1 MIX-7 2.3 0.9164 0.18 yes 1.71 1.7inventive 60% 40& LLDPE-4 11 60% -MIX-LL 2.6 0.9170 N / A yes0 non- LLDPE-1 0.01 inventive 40% 12 SRM-1 LLDPE-3 inventiveMIX-8 2.6 0.9199 0.09 yes 0.82 1.660% 40% LLDPE-1 13 SRM-1 20% inventive 60%MIX-9 2.4 0.9192 0.08 yes 0.83 2.1LLDPE-3 20% Table 2 Example CompositionMaximum Strain extensibility *hardening of the tested film of the film 1 30% SRM-1 + 20% LLDPE-1 + 50% yes 550% inventive LLDPE-4 2 non-100% LLDPE-4 560% noinventive 3 non-30% SRM-1 + 70% LLDPE-4 340% not measuredinventive 4 30% SRM-1 + 20% LLDPE-2 + 50% non-330% not measuredLLDPE-4 inventive 5 30% SRM-1 + 20% LLDPE-1 + 50% non-470% not measuredLLDPE-4 inventive 6 30% SRM-2 + 20% LLDPE-1 + 50% non-350% not measuredLLDPE-4 inventive 7 40% SRM-1 + 10% LLDPE-1 + 50% yes 505% inventive LLDPE-4 8 15% SRM-1 + 35% LLDPE-1 + 50% yes 550% inventive LLDPE-4 9 15% SRM-1 + 35% LLDPE-2 + 50% non-430% not measuredLLDPE-4 inventive 1030% SRM-3 + 20% LLDPE-1 + 50%580% Yesinventive LLDPE-4 11 non-20% LLDPE-1 + 80% LLDPE-4 550% not measuredinventive 12 30% SRM-1 + 20% LLDPE-1 + 50% Yes 560% inventive LLDPE-4 13 30% SRM-1 + 10% LLDPE-1 + 10% Yes 515% inventive LLDPE-3 + 50% LLDPE-4 Table 3 * The term "YES" in the "Strain hardening" column indicates the presence of an inflection point in theelongational viscosity curve, representing the increasing trend of the values of the elongational viscosity measurements (ordinates) carried out on a sample of the composition, after maintaining for 5 minutes at 130°C, and at a Hencky strain rate of 1 s-1, with respect to time (abscissas). Comparing example 1 (inventive) with example 2 (non-inventive) it is evident that the MIX-1 composition (example 1) exhibits a maximum film extensibility comparable to a product such as LLDPE-4 (example 2), specially designed to be used in the form of a stretch film. However, the film obtained from LLDPE-4, as pointedout above, does not possess any "strain hardening", sincethe graph in figure 6 shows an elongational viscositycurve with respect to time that goes towards a plateauand does not present any inflection point. The differencein the trend of the elongational viscosity curve withrespect to the time of MIX-1 compared to LLDPE-4 is evenmore visible in the comparison graph reported in figure 7. The comparison among example 1 (inventive), example3 (non-inventive), example 12 (inventive), example 13(inventive) and example 4 (non-inventive) points out theneed to mix the mixture of recycled plastic material(SRM) with an suitable component (e.g. LLDPE-1, LLDPE-3or a mixture of the two), in order to obtain stretchfilms having a maximum extensibility value higher than500% and excellent rheological properties such as "strain hardening". The comparison between example 1 (inventive) and example 5 (non-inventive) underlines the need of filtering the mixture of recycled material (SRM), in order to obtain a stretch film with a maximumextensibility value higher than 500% and excellentrheological properties such as "strain hardening".Surprisingly, the filtration aperture applied to thefilter (89 microns), which is much higher than the finalthickness of the article on which the film extensibilitytests were carried out (23 microns), improves the performance of a much thinner film. The comparison between example 1 (inventive) andexample 6 (non-inventive) points out the SRMcharacteristics required to obtain a stretch film witha maximum extensibility value higher than 500% andexcellent rheological properties such as "strain hardening". Examples 7-8 (inventive) point out the possibilityof modulating the amount of LLDPE-1 to be used in a mixture with SRM-1 to obtain a stretchable thin filmhaving a maximum extensibility value higher than 500%and excellent rheological properties such as "strain hardening". The comparison between example 9 (non-inventive) and example 8 (inventive) confirms the need to mix SRM- 1 with an appropriate component (LLDPE-1), in order to obtain a stretch film, as already indicated by the comparison between example 1 (inventive) and example 4 (non-inventive). Furthermore, the rheological behaviour showed by MIX-1, MIX-4, MIX-5, MIX-7, MIX-8 and MIX-9 respectively present in examples 1, 7, 8, 10, 12, 13, compared to LLDPE-4 is advantageous: a higher elongational viscosity in fact translates into operational advantages. As indicated in the literature already mentioned above,higher elongational viscosity corresponds to betterdimensional stability of the material subjected to stretching at the exit from the flat head. It is also evident that the rheological characteristics of the material are directly correlated with the percentage integration value of the resonance signal A at 32.62 ppm, present in the13C-NMR spectrum, acquired under the operating conditions reported in the analysis and testing section of the experimental part. In particular, it was determined that at percentage integration values of A in the range between0.2 and 4.0%, the film obtained shows rheologicalcharacteristics of elongational viscosity suitable for stretch film applications with a maximum extensibilityvalue higher than 500% and excellent rheologicalproperties such as "strain hardening".

Claims

CLAIMS1. Polyethylene-based polymer compositioncomprising: -20-90%, calculated on the total weight of thecomposition, of a mixture of recycled plastic material (SRM), said material being recovered from polyethylene-based waste plastic materials,derived from post-consumer and defined accordingto ASTM D5491-08:2022; and said recycled plasticmaterial (SRM) being characterized by having: -a DSC curve having at least one peak between 60° and 130°C, and a fusion heat ΔH, between 100 and 200 J / g, measured between 20 and 145°C,said curve being obtained during the second heating in the following thermal treatment: a heating from 0 to 200°C at 20°C / min, an isotherm at 200°C for one minute, a cooling at 5°C / min up to 0°C, an isotherm at 0 °C for one minute and a second heating from 0 to 200°C at 5°C / min; -a melt flow rate (MFR), between 1.0 and 5.5g / 10 min, preferably between 1.5 and 3.0 g / 10 min, said index being measured at 190°C and by applying a weight of 2.16 kg in accordance with standard ISO 1133-1:2022; -a density between 0.9000 and 0.9300 g / cm3, preferably between 0.9100 and 0.9270 g / cm3, measured in a gradient column in accordance with standard ISO 1183-1:2019;-a carbonyl index (CI), defined as the ratio between the intensities of the bands in the FTIR spectrum at 1740 and 2020 ± 1 cm-1, between 0.8 and 10, preferably between 0.9 and 5.0; said spectrum being recorded by analysing a film with thickness of 500 microns, obtained from the mixture of recycled plastic material (SRM) by moulding with a press preheated to 150°C; -an ash content, equal to at least 0.03%, preferably between 0.05 and 2.00%, still more preferably between 0.08 and 0.70%, said content being measured as residue of a thermal post-treatment of the recycled polymeric material (SRM) carried out at a temperature of 550 ±5°C; -a ratio between the concentration of tris(2,4-di-tert-butylphenyl) phosphite (additive A) and the concentration of tris(2,4-di-tert-butylphenyl) phosphite in oxidized form (additive B) less than 1, more preferably less than 0.7, said ratio being measured by a gas chromatography analysis carried out by gas chromatography;- 10-80%, calculated on the total weight of thecomposition, of one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, said polymers being characterized by a density,measured in a gradient column in accordance with ISO 1183-1:2019, between 0.8800 and 0.9350 g / cm3, and a melt flow rate (MFR), determined at 190°C and with a weight of 2.16 kg in accordance with ISO 1133-1:2022, between 1.0 and 4.0 g / 10 min; said composition being characterized by: -a 13C NMR spectrum comprising thefollowing signals at 11.03, 11.19, 23.37, 32.16 and 32.62 ± 0.10 ppm, wherein thepercentage ratio (A%) between the value of the integration of the signal at 32.62 ± 0.10 ppm(A) and the sum of the values of the integrations of the signals at 32.62, 32.16, 23.37, 11.19 and 11.03 ± 0.10 ppm, is between0.2 and 4.0%, preferably between 0.3 and 2.5%; wherein said signals represent13C carbons of branching of polyethylene polymers constituting the composition; -a melt flow rate (MFR), between 1.0 and 5.5g / 10 min, preferably between 1.5 and 3.0 g / 10 min, said index being measured at 190°C with a weight of 2.16 kg in accordance with ISO 1133- 1:2022;- a density between 0.8800 and 0.9210 g / cm3,said density being measured in a gradient column in accordance with ISO 1183-1:2019; -having passed a filtration test, carried outby operating with an average mass flow rate of5 ±0.5 kg / h and with a temperature profile of170°C (hopper) - 200°C (extruder barrels) -210°C (die), in a single screw extruder, having a diameter (D) of 30 mm, a length / diameter ratio (L / D) of 28 and including a filter,characterized by an aperture equal to 89microns; said test being passed when the following condition occurs: ΔPfin < 2 ΔPinwherein: -ΔPin is the initial pressure difference,calculated after 5 minutes of testing, by subtracting the pressure measured downstream of the filter from that measured upstream of the same; -^Pfin is the final pressure difference,calculated after 60 minutes of testing, subtracting the pressure measured downstream of the filter from the pressure measured upstream of the same; -an ash content, equal to at least 0.02%, preferably between 0.03 and 2.00%, even more preferably between 0.04 and 0.25%, said content being measured as residue of a thermal post-treatment of the polyethylene-based polymer composition carried out at a temperature of 550 ± 5°C;-a carbonyl index (Ic) value between 0.7 and 10.0, preferably between 0.8 and 2.0, said index being calculated as the ratio between intensities of the absorption bands present in the FT-IR spectrum at 1740 and 2020 ± 1 cm-1respectively.

2. Polymer composition according to claim 1, comprising 15-75% of one or more linear low density polyethylene polymers (LLDPE), not coming from post- consumer recycled plastic material.

3. Polymer composition according to any of the previous claims, wherein the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, are copolymers of ethylene with at least one α-olefin.

4. Polymer composition according to claim 3, wherein the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, are copolymers of ethylene with at least one α-olefin, having from 3 to 12 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 8 carbon atoms.

5. Polymer composition according to claim 4, wherein the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, are copolymers of ethylene with at least one α-olefinselected from 1-butene, 1-hexene and 1-octene or mixtures thereof.

6. Polymer composition according to claim 5, wherein the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, are characterized by having: i. a density between 0.8800 and 0.9210 g / cm3, said density being measured in a gradient column in accordance with ISO 1183-1:2019;ii. a melt flow rate (MFR) between 1.5 and 4.0 g / 10min, said index being determined at 190°C and with a weight of 2.16 kg in accordance with ISO 1133- 1:2022.

7. Process for preparing the polymeric composition defined according to any one of claims 1 to 6, comprising the following steps: a. melting the recycled plastic mixture (SRM);b. filtering the material obtained in step (a) inthe molten state using a filter characterized by an aperture not higher than 99 microns, preferablybetween 50 and 89 microns; c. melting one or more linear low densitypolyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material; d. mixing the polymeric material obtained fromstep (b) with that obtained from step (c) in the molten state.

8. Process for preparing the polymeric composition according to claim 7, wherein in step (d) the weight ratios between the recycled plastic material (SRM) and the one or more linear low density polyethylene polymers (LLDPE), not coming from post-consumer recycled plastic material, are between 20:80 and 90:10, preferably between 25:75 and 85:15, even more preferably they are 60:

40.

9. Granules comprising the polymeric composition according to any one of claims 1 to 6.

10. Use of the polymer composition according to oneof claims 1 to 6, in the production of polymeric films obtained through a cast film transformation process, said films being characterized by amaximum extensibility higher than 500%, by thepresence of strain hardening, and by a thickness between 20 and 100 microns.

11. Use of the granules according to claim 9, for the production of polymeric films obtained through a cast film transformation process, said films being characterized by a maximum extensibilityhigher than 500%, by the presence of strainhardening, and by a thickness between 20 and 100 microns.

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