Biaxially oriented polypropylene film with high density and improved optical properties

Abstract

The present invention relates to a biaxially oriented polypropylene film comprising at least one layer which comprises a polypropylene composition (PC), wherein the polypropylene composition (PC) comprises a mixed-plastic polypropylene recycling blend having i) a polypropylene content of from 92 to 99.7 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by Fourier-transform infrared (FTIR) spectroscopy as described in the specification; ii) a melt flow rate MFR2 in the range of from 3 to 10 g / 10 min; iii) a content of inclusions of a density of at least 1.1 g / cm3 of up to 0.45 vol.-%, wherein the content of inclusions of a density of at least 1.1 g / cm3 and equal to or lower than 1.53 g / cm3 is in the range of from 0.01 to less than 0.40 vol.-%, the contents of inclusions being indicated relative to the total volume of the mixed-plastic polypropylene recycling blend and determined by X-ray Computed Tomography (X-ray CT); iv) a sum of contents of contaminants selected from polyamide, polystyrene, and chalk of less than 1.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend, the content of polyamide and polystyrene being determined by Fourier-transform infrared (FTIR) spectroscopy infrared spectroscopy, and the content of chalk being determined by thermogravimetric analysis (TGA); and v) a content of soluble fraction (SF) in the range of from 3.0 to 12.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend, wherein the soluble fraction (SF) has an intrinsic viscosity (IV(SF)) of below 1.1 dl / g, the content of soluble fraction (SF) and the intrinsic viscosity (IV(SF)) being determined according to CRYSTEX QC analysis. The used mixed-plastic polypropylene recycling blend is prepared by a specifically designed recycling process. Such a biaxially oriented polypropylene film is useful for packaging, labelling, medical or optical applications.

Description

[0001] Biaxially oriented polypropylene film with high density and improved optical properties

[0002] The present invention relates to biaxially oriented polypropylene films comprising at least one layer which comprises a polypropylene composition encompassing a mixed-plastic polypropylene blend as typically originating from recyclates. The mixed-plastic polypropylene blend is improved in having high density and superior optical properties making it highly suitable for film applications, in particular making improved biaxially oriented polypropylene films.

[0003] Background of the Invention

[0004] Polyolefins, in particular polyethylene and polypropylene, are increasingly consumed in large amounts in a wide range of applications, including packaging for food and other goods, fibers, automotive components, and a great variety of manufactured articles. Polypropylene flexible packaging articles, and therefore waste comprising these systems, are in general heavily printed, often metallized, small in size, and in contact to biological contaminations. These attributes result in a high contamination level, dark color, odor and emissions, which challenge mechanical recycling. In particular, film application requires high quality grades and challenges intrinsic material properties of recyclate materials. During the last decade, concern about plastics and the environmental sustainability of their use in current quantities has grown. This has led to new legislation on disposal, collection and recycling of polyolefins. There have additionally been efforts in a number of countries to increase the percentage of plastic materials being recycled instead of being sent to landfill.

[0005] In Europe, plastic waste accounts for approximately 27 million tons of waste a year; of this amount in 2016, 7.4 million tons were disposed of in landfill, 11.27 million tons were burnt (in order to produce energy) and around 8.5 million tons were recycled. Polypropylene based materials are a particular problem as these materials are extensively used in packaging. Taking into account the huge amount of waste collected compared to the amount of waste recycled back into the stream (amounting to only about 30 %), there is still a great potential for intelligent reuse of plastic waste streams and for mechanical recycling of plastic wastes.

[0006] However, it is commonly quite difficult to obtain either pure recycled polypropylene. Generally, recycled quantities of polypropylene on the market are mixtures of bothpolypropylene (PP) and polyethylene (PE); this is especially true for post-consumer waste streams. Commercial recyclates from post-consumer waste sources have been found generally to contain mixtures of PP and PE, the minor component reaching up to < 50 wt.-%.

[0007] The better the quality, i.e. the higher the purity, of the recycled polyolefin the more expensive the material is. Moreover, recycled polyolefin materials are often cross-contaminated with non-polyolefin materials, such as polyethylene terephthalate, polyamide, and polystyrene or non-polymeric substances like wood, paper, glass or aluminum.

[0008] In addition, recycled polypropylene rich materials normally have properties that are much worse than those of the virgin materials are, unless the amount of recycled polyolefin added to the final compound is extremely low. For example, such materials often have poor performance in odor and taste, limited stiffness, limited impact strength and poor mechanical and optical properties. Thus, they do not fulfil customer requirements.

[0009] Many attempts have been made for purifying recycling streams as originating from post¬ consumer trash / waste. Among those measures washing, sieving, aeration and the like may be mentioned. Undesirable coloration of the recycled polypropylene fraction is still a remaining problem not completely addressed.

[0010] In addition to the requirements for balanced mechanical properties and high purity, polypropylene labels are often required to be white or transparent. As such, the development of recycling processes that yield high purity recyclates having a desirable balance of properties (including transparent or white fractions) is important for allowing recyclates to be used in a broader range of applications.

[0011] Waste Management 153 (2022) 43-51 and Waste Management 153 (2022) 249-263 disclose recycling tests for polypropylene flexible film packaging (CEFLEX trials). The recycling process used is said to be the most advanced, although no details are provided on how to operate the process. The papers disclose recycled polypropylene fractions (rPP) containing only 79% PP. Thus, films made from rPP are at best able to match one key property, while scoring poorly on others and reaching around 50 % of the properties for the remaining key values obtained with a respective virgin polypropylene. This indicates that it is unlikely that the recycled material can substitute virgin polypropylene as such.

[0012] WO 2023 / 209075 A1 discloses a flexible grade recycled polypropylene blend (PP-flex) produced starting from mixed applications of post-consumer waste (PCW) via amechanical recycling process and with a PCR content of 100% demonstrating a high PP purity, a high product quality, a bright shade, improved quality regarding odour and emissions.

[0013] The grade is obtained via colour sorting of the PP material to produce a fraction comprising of transparent, or natural colored components, not or weakly printed, un¬ metallised. No dark or black colored components, or white or light colored components are contained.

[0014] EP 23200 103.2 discloses an improved mechanical recycling process and the properties of a mixed-plastic polypropylene blend obtained from labels is described.

[0015] A specific demand exists for recyclates suitable for flexible articles such as films.

[0016] Flexible packaging feedstock has a very heterogeneous composition (see J. Schmidt et al., Polymers 2022, 14(9), 1825; G. Koinig et al., Polymers 2022, 14(8), 1553; M. Roosen et al., Environ. Sci. Technol. 2020, 54, 13282). Even with advanced sorting and washing technologies, when recycling feedstock containing packaging waste including laminates with barrier and functional layers, as well as reverse printing, the number of residual inclusions can be still very high. This represent a limitation for incorporating the recyclates back into film applications, as the number of inclusions is too high for achieving advanced mechanical and optical properties. Properties of the resulting films is below the standards and unacceptable to customers.

[0017] There is a continuing need to replace virgin PP, so that advanced recyclate material are required which do not compromise the final properties of a mixed polypropylene composition intended for film applications. Above that, transparent film applications require high density and minimization of cavitation to achieve improved optical, mechanical and barrier properties.

[0018] It is known that biaxially oriented polypropylene (BOPP) films have certain advantages in advanced technical applications such as, for example, packaging, tapes or capacitor films. However, due to the production of the BOPP film by sequential or simultaneous drawing in two orthogonal directions, at two different temperatures, the BOPP film processing introduces considerable anisotropy regarding several mechanical properties of the final BOPP film. In particular, the relaxation of the morphology upon heating causes shrinkage in both drawing directions.

[0019] Moreover, in the past it was necessary to increase the isotacticity and melting point of the base resin used for preparing the BOPP film to increase the stiffness, i.e. the modulus of elasticity of the final BOPP film. At the same time, however, the increase in isotacticityand melting point typically reduces the toughness, i.e. the elongation at break, of the BOPP film prepared from such a resin.

[0020] Among others, mechanical properties such as low shrinkage, high dimensional stability, high stiffness, yet requiring a certain level of flexibility for the orienting process, and high toughness are desired for BOPP films. It is still complex and difficult to achieve a combination of these properties, in particular if the film comprises recyclate materials. Transparent BOPP films used for packaging applications require high clarity and transparency to view the packaged contents and further robustness of the film (good mechanical properties, in particular high tensile strength). The presence of incompatible particles, like inorganic residuals typically present in recyclate materials involve the problem of cavitation, i.e. the formation of voids and cavities. Voids diffract light, thus increasing the opacity of the film. Cavitation also reduces the film density and other physical properties of the BOPP film, such as the modulus and craze resistance.

[0021] Thus, the control of the cavitation process is important as the size, shape, and distribution of the generated voids during the stretching process are directly responsible for the light scattering properties in the final film. The occurrence of cavitation transparent BOPP films is an unwanted phenomenon and deteriorates the suitability of BOPP films in advanced applications. Thus, cavitation and the occurrence of voids by cavitation should be minimized.

[0022] Thus, it is an object of the present invention to provide a biaxially oriented polypropylene film comprising a mixed-plastic polypropylene recycling blend, the film having high density, minimized cavitation induced by inclusions, and improved optical properties such as haze, clarity and transmittance. It is a further object of the present invention to provide an improved mixed-plastic polypropylene recycling blend and process for its preparation to be used for making the biaxially oriented polypropylene film. A further object of the present invention is the use of the disclosed BOPP films for packaging, labelling, medical or optical applications.

[0023] Summary of the Invention

[0024] The present invention has found that the above objects can be achieved by providing a biaxially oriented polypropylene film comprising at least one layer which comprises a polypropylene composition (PC), wherein the polypropylene composition (PC) comprises a mixed-plastic polypropylene recycling blend having:i) a polypropylene content of from 92 to 99.7 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by Fourier-transform infrared (FTIR) spectroscopy as described in the experimental part below;

[0025] ii) a melt flow rate MFR2 in the range of from 3 to 10 g / 10 min, determined according to ISO 1133, 230 °C, 2.16 kg;

[0026] Hi) a content of inclusions of a density of at least 1.1 g / cm3of up to 0.45 vol.-%, wherein the content of inclusions of a density of at least 1.1 g / cm3and equal to or lower than 1.53 g / cm3is in the range of from 0.01 to less than 0.40 vol.-%, the contents of inclusions being indicated relative to the total volume of the mixed- plastic polypropylene recycling blend and determined by X-ray Computed Tomography (X-ray CT) as described in the experimental part below;

[0027] iv) a sum of contents of contaminants selected from polyamide, polystyrene and chalk of less than 1.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by Fourier-transform infrared (FTIR) spectroscopy as described in the experimental part below; and v) a content of soluble fraction (SF) in the range of from 3.0 to 12.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend, wherein the soluble fraction (SF) has an intrinsic viscosity (IV(SF)) of below 1.1 dl / g, the content of the soluble fraction (SF) and the intrinsic viscosity (IV(SF)) being determined by CRYSTEX QC analysis as described in the experimental part below.

[0028] The present invention is based on the observation that the use of the above mixed-plastic polypropylene recycling blend for making BOPP films achieves such BOPP films having superior properties such as high density, minimized cavitation induced by inclusions, and improved optical properties such as haze, clarity and transmittance. These properties can be obtained by a particularly designed recycling process. Due to its low content of contaminants as well as its good rheological and physical properties, the mixed-plastic polypropylene recycling blend according to the present invention can be used in for advanced applications of the obtained BOPP films such as packaging, labelling, medical or optical applications.

[0029] Preferred embodiments of such a biaxial ly oriented polypropylene film are defined in the dependent claims below.

[0030] The present invention is further directed to the use of the biaxially oriented films for packaging, labelling, medical or optical applications.Definitions

[0031] As used herein, “mixed plastic" denotes plastic objects originating from plastic waste, i.e. , having completed at least a first use cycle (or life cycle) and having already served their first purpose.

[0032] As used herein, “post-consumer waste" (PCW) denotes waste used by consumers such as in private households. For example, the post-consumer waste originates from conventional collecting systems, e.g., as those implemented in the European Union. In contrast, “industrial waste” denotes manufacturing scrap, which does not normally reach a consumer. Preferably, the mixed plastic originates from post-consumer waste.

[0033] It should be understood that mixed plastic may vary broadly in composition, i.e., it may include polyolefin homopolymers and polyolefin copolymers.

[0034] A waste stream according to the present invention, is a consumer waste stream, such a waste stream may originate from conventional collecting systems such as those implemented in the European Union. Mixed plastic may e.g. be defined as the presence of low amounts of compounds usually not found in virgin polypropylene blends such as polystyrenes, polyamides, polyesters, wood, paper, limonene, aldehydes, ketones, fatty acids, metals, and / or long term decomposition products of stabilizers. Virgin polypropylene blends denote blends as directly originating from the production process without intermediate use. Thus, virgin materials and recycled materials easily can be differentiated based on absence or presence of contaminants such as limonene and / or fatty acids and / or paper and / or wood.

[0035] The mixed-plastic polypropylene recycling blend contained in the inventive films is in particular characterized by reduced amount of the sum of contents of contaminants selected from polyamide, polystyrene and chalk as defined in claim 1.

[0036] It further will be understood by those skilled in the art that a soluble fraction (SF) as obtained by CRYSTEX QC analysis having an intrinsic viscosity (iV(SF)) in the range from 1.10 to below 1.50 dl / g is typically found in material from recycling streams. According to the invention the soluble fraction (SF) as obtained by CRYSTEX QC analysis has an intrinsic viscosity of the soluble fraction (iV(SF)) of below 1.1 dl / g.

[0037] It should be understood that mixed plastics may vary broadly in composition, i.e. may include polyolefin homopolymers and polyolefin copolymers. Mixed plastic may e.g., be defined based on the presence of contaminants usually not found in virgin polypropylene blends, such as polystyrenes, polyamides, polyesters, wood, paper, limonene, aldehydes, ketones, fatty acids, inorganic elements, organic components, and / or long-termdecomposition products of stabilizers. Virgin polypropylene blends denote blends directly originating from the production process without intermediate use. Thus, virgin materials and recycled materials can be easily differentiated based on the absence or presence of contaminants as described above.

[0038] Accordingly, as used herein, "mixed-plastic polypropylene recycling blend” denotes a recycling product obtained from mixed plastic and comprising a high content of polypropylene. A "blend” denotes a mixture of two or more components, presently polypropylene components. The polypropylene components may be in the form of propylene homopolymers and / or propylene copolymers. Propylene homopolymers generally comprise at least 98 wt.-%, based on the total weight of the propylene homopolymer, of units derived from propylene. Propylene copolymers generally denote polymers comprising at least 50 wt.-%, based on the total weight of the propylene copolymer, of units derived from propylene, and further comprising units derived from other monomers, such as ethylene and / or alpha-olefin units having from 4 to 12 carbon atoms. The mixed-plastic polypropylene recycling blend generally has a broadened molecular weight distribution when compared to virgin polymers because it is a mechanical blend of countless polypropylenes and some amounts of polyethylenes. Since the mixed-plastic polypropylene recycling blend contains material originating from flexible polymer articles, it is usually a blend of polypropylenes and some amounts of polyethylene-based materials (e.g., polyethylene films).

[0039] The wording "flexible polymer articles” is well known in the art of polymer technology and is contrasted to the wording "rigid polymer articles”. For example, a distinction may be made based on the thickness of these articles, i.e., typically, flexible polymer articles are objects that are thinner than 120 pm. The thickness can be measured on a sample of flexible polymer articles by a micrometer gauge. Usually, flexible polymer articles are objects made from thin continuous plastic materials, i.e., plastic films, fibers, and all plastic fabrics (e.g., woven and melt-blown fibers). A flexible polymer article feedstock stream typically comprises objects, wherein at least 70 wt.-% of the objects are flexible polymer articles, i.e., are thinner than 120 pm.

[0040] The term “article form”, as used herein, refers to the shape and form of articles present in a polyolefin recycling stream. Such articles may be present, inter alia, in the form of films, bags, and pouches, which may be considered as flexible articles, and, inter alia, in the form of molded articles such as food containers, skin-care product containers, and plastic bottles, which may be considered as rigid articles. Commercial optical sorters, such as Tomra Autosort, RTT Steinert Unisort, and Redwave Pellenc, are able to separate so-called rigid articles from so-called flexible articles via their aerodynamic properties (i.e. a stream of gas is typically applied to the stream and those articles being rigid articles will fall with a different arc than flexible articles), converting streams containing such articles into so-called rigid streams and flex streams.

[0041] Said polymeric materials can be identified in the mixed plastic polypropylene recycling blend by means of quantitative13C{1H} NMR measurements as described herein. In the quantitative13C{1H} NMR measurement used herein and described below in the measurement methods different units in the polymeric chain can be distinguished and quantified. These units are propylene units (C3 units), units having 2, 4 and 6 carbons and units having 7 carbon atoms. Thereby, the units having 2 carbon atoms (C2 units) can be distinguished in the NMR spectrum as isolated C2 units and as continuous C2 units which indicate that the polymeric material contains an ethylene based polymer. The mixed plastic polypropylene recycling blend used in the present invention usually include low amounts of ethylene-based polymeric components.

[0042] Conventionally, further components such as fillers, including organic and inorganic fillers for example talc, chalk, carbon black, and further pigments such as TiCh as well as paper and cellulose may be present.

[0043] Preferably, the mixed plastic polypropylene recycling blend may be obtained from a transparent fraction of a mixed polypropylene post-consumer waste (PCW) feedstock. It is characterized by the parameters as defined in claim 1 and may preferably be contained in at least one layer of the biaxially oriented polypropylene film of the invention in an amount of 25 to 100 wt.-%, more preferably from 30 to 100 wt.-%, even more preferably from 35 to 100 wt.-%, based on the total weight of the layer composition.

[0044] A virgin propylene polymer (v-PP) denotes a newly produced materials and / or objects prior to their first use, which have not already been recycled. The virgin material preferably is a polypropylene comprising at least 90 wt.-% of a reactor made polypropylene material, as well as optionally carbon black. The virgin polypropylene may be selected from heterophasic polypropylenes, random propylene copolymers, and propylene homopolymers.

[0045] All measurements according to the test methods described in the experimental part below were done on melt-extruded and pelletized samples of the final polypropylene recycling product as obtained by the recycling method described below.

[0046] If not indicated otherwise, “%” denotes weight percent.Brief Description of the Figures

[0047] Fig. 1 shows the results for clarity, transmittance and haze of the films according to Example 3.

[0048] Fig. 2 shows the optical effects of the films according to Example 3 by their visual appearance.

[0049] Detailed Description of the Invention

[0050] BOPP films

[0051] The present invention is generally directed to a biaxially oriented polypropylene film comprising at least one layer which comprises a polypropylene composition (PC) comprising or consisting of a PP recycled blend as defined in claim 1 below. The present invention found that such films are characterized by high density and minimized cavitation induced by inclusions. Preferably, the final density of the films is not less than 0.880 g / cm3The final density of the film may preferably be not less than 0.8 g / cm3or not less than 0.7 g / cm3. The final density of the film may preferably be up to 0.93 g / cm3.

[0052] The present invention further found that such films are characterized by excellent optical properties, such as clarity, haze, transmittance, and gloss. Preferably the films of the invention show a clarity of at least 81 %, more preferably at least 83%, a haze of preferably not more than 16.5 %, more preferably not more than 15 %, a transmittance of preferably at least 85.0 %, more preferably at least 87.0 %, a gloss measured at an angle of 45° in machine direction (MD) of preferably at least 80 %, more preferably at least 85 %, and / or a gloss measured at an angle of 45° in transverse direction (TD) of preferably at least 80 %, more preferably at least 83 %. The measurement methods are described in detail in the experimental part below.

[0053] The BOPP films of the present invention may preferably comprise a PP composition comprising a blend of the mixed-plastic polypropylene recycling blend and of a virgin polypropylene (PP). More preferably, the PP composition consists of a blend of the mixed- plastic polypropylene recycling blend and a virgin polypropylene (v-PP).

[0054] The BOPP film according to the invention may preferably comprise at least 90 wt.-%, more preferably up to 99 wt.-% of the polypropylene composition (PC), based on the total weight of the film. The remaining part up to the 100 wt.-% may be provided by additives. The additives are additives generally used to prepare a BOPP film. Suitable additives are, for example, UV stabilizers, antistatic agents, antioxidants etc. The skilled person is aware ofthe suitable additives to be added to the PP composition to prepare a BOPP film. In case suitable additives are already comprised in the mixed-plastic polypropylene recycling blend and / or in the virgin polypropylene, the BOPP film preferably consists of the PP composition.

[0055] Preferably, the PP composition does not comprise a virgin polypropylene. Accordingly, the PP composition consists of the mixed-plastic polypropylene recycling blend and optionally suitable additives.

[0056] The BOPP film according to the invention may preferably comprise at least 20 wt.-%, more preferably at least 25 wt.-%, even more preferably at least 30 wt.-%, of said recycling mixed plastic polypropylene blend, based on the total weight of the film.

[0057] The BOPP film according to the invention may preferably comprise up to 100 wt.-%, more preferably up to 95 wt.-%, even more preferably up to 90 wt.-%, of said recycling mixed plastic polypropylene blend, based on the total weight of the film.

[0058] The BOPP film according to the invention can be a monolayer film or a multilayer film. The terms “monolayer film” and “multilayer film” have well known meanings in the art. The BOPP film is preferably a multilayer film. In a multilayer film, at least one layer comprises the BOPP film as described herein. Said at least one layer may preferably comprise from 25 to 100 wt.-%, more preferably from 30 to 100 wt.-%, even more preferably from 35 to 100 wt.-% of said mixed plastic polypropylene recycling blend, based on the total weight of the at least one layer.

[0059] According to the invention, the biaxially oriented polypropylene (BOPP) film may be a monolayer film, wherein said monolayer film consists of the polymer composition (PC). Preferably, the at least one layer is the core layer of the multilayer film.

[0060] Particularly preferred multilayer films are a 3-layer film (ACE) or a 5-layer film (ABCDE), wherein the core layer (C) consists of the polypropylene composition (PC).

[0061] In such 3-layer films (ACE) and 5-layer films (ABCDE), it is preferred that at least one of the skin layers (A / E), preferably both of the skin layers, comprise(s) at least 80 wt.-% of a terpolymer containing monomer units derived from any one of ethylene and a C4-8 alpha olefin.

[0062] It is particularly preferred that the terpolymer is a C3C2C4 terpolymer, i.e. that the C4-8 alpha olefin is 1 -butene.

[0063] It is preferred that the terpolymer has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 0.5 to 12.0 g / 10 min, more preferablyin the range from 2.5 to 10.0 g / 10 min, even more preferably in the range from 5.0 to 9.0 g / 10 min.

[0064] It is preferred that the terpolymer has an ethylene content, determined by quantitative13C-NMR analysis, as determined in the experimental section below, in the range from 0.1 to 3.0 wt.-%, more preferably in the range from 0.3 to 2.0 wt.-%, most preferably in the range from 0.5 to 1.5 wt.-%.

[0065] It is preferred that the terpolymer has an C4-8 alpha olefin content, more preferably a 1-butene content, determined by quantitative13C-NMR analysis, as determined in the experimental section below, in the range from 4.0 to 15.0 wt.-%, more preferably in the range from 6.0 to 12.0 wt.-%, most preferably in the range from 8.0 to 10.0 wt.-%.

[0066] It is preferred that the terpolymer has a melting temperature (Tm), determined according to ISO 11357, in the range from 115 to 144 °C, more preferably in the range from 120 to 139 °C, most preferably in the range from 125 to 134 °C.

[0067] It is preferred that the terpolymer has a crystallization temperature (Tc), determined according to ISO 11357, in the range from 90 to 105 °C, more preferably in the range from 90 to 100 °C, most preferably in the range from 90 to 95 °C.

[0068] It is preferred that the terpolymer has a glass transition temperature (Tg) determined by dynamic mechanical analysis (DMA), as determined in the experimental section below, in the range from -12 to +5 °C, more preferably in the range from -8 to +2 °C, most preferably in the range from -4 to 0 °C.

[0069] If layers (B) and (D) are present, then these layers may consist of the polypropylene composition (PC) as defined above. The polypropylene composition (PC) of layers (B) and (D) may be the same or different and may be the same or different to the polypropylene composition of layer (C), so long as the polypropylene compositions (PC) of each layer individually meet the requirements of the polymer composition (PC) as defined in the present claims.

[0070] The BOPP film of the present invention may preferably comprise a core layer C and at least external layers E1 and E2, wherein the core layer C may comprise from 25 to 100 wt.-%, preferably from 30 to 100 wt.-%, more preferably from 35 to 100 wt.-% of said mixed plastic polypropylene recycling blend, based on the total weight of the core layer. Any layer that does not comprise mixed plastic polypropylene recycling blend may typically comprise, preferably consist of a polypropylene. The layer may encompass a single polypropylene or a blend of polypropylenes. More preferably, the polypropylene may be selected from a propylene random copolymer, such as a propylene-ethylenerandom copolymer, a heterophasic propylene copolymer, such as a heterophasic propylene-ethylene copolymer, and propylene terpolymers comprising comonomers selected from C2, C4 to Cs alpha-olefins.

[0071] A monolayer or a multilayer film may preferably have a thickness of from 10 to 120 pm, more preferably from 12 to 100 pm and even more preferably from 15 to 80 pm or 20 to 60 pm.

[0072] Surprisingly, the BOPP films of the present invention preferably have a clarity determined according to ASTM D1003 and as described in the experimental section below, of at least 81 %, more preferably at least 83 %.

[0073] Surprisingly, the BOPP films of the present invention preferably have a haze, determined according to ASTM D1003 and as described in the experimental section below, of not more than 16.5 %, more preferably not more than 15 %.

[0074] Surprisingly, the BOPP films of the present invention preferably have a transmittance, determined according to ASTM D1003 and as described in the experimental section below, of at least 85.0 %, more preferably at least 87.0 %.

[0075] Surprisingly, the BOPP films of the present invention preferably have a gloss measured at an angle of 45° in machine direction (MD) according to ASTM D2457 and determined as described in the experimental section below, of at least 80 %, more preferably at least 85 %.

[0076] Surprisingly, the BOPP films of the present invention preferably have a gloss measured at an angle of 45° in transverse direction (TD) according to ASTM D2457 and determined as described in the experimental section below, of at least 80 %, more preferably at least 83 %.

[0077] The advantageous properties of the BOPP films of the present invention, as described above make them highly useful in many advanced technical applications such as packaging, labelling, medical or optical applications.

[0078] Process for making BOPP films

[0079] The films of the present invention may be prepared by a process for sequential or simultaneous biaxially orienting (stretching) a polypropylene composition (PC) as defined above. In general, a process for producing a biaxially oriented polypropylene film as defined above, comprises the steps of:

[0080] (A) providing a polypropylene composition (PC) as defined above and below,(B) extruding the polypropylene composition (PC) to a flat film,

[0081] (C) orienting, optionally simultaneously orienting the flat film, in the machine direction and in the transverse direction to obtain a biaxially oriented polypropylene film, and (D) recovering the biaxially oriented polypropylene film.

[0082] It is preferred that step (C) is carried out in that the flat film obtained in step (B) is stretched a) in machine direction (MD) with a draw ratio of at least 3.0, preferably at least 4.0, and / or b) in transverse direction (TD) with a draw ratio of at least 6.0, preferably at least 7.0. Preferred processes for biaxially orienting polypropylene films that can be applied to the present invention are disclosed e.g. in WO 2015 / 091829 A1, WO 2015 / 091839 A1, WO 2020 / 127861 A1 or WO 2020 / 127862 A1.

[0083] The biaxially oriented polypropylene (BOPP) film is preferably prepared by a process comprising the following steps:

[0084] a) forming a precursor film (PF), preferably either a cast precursor film (CPF) or a blown precursor film (BPF) comprising one or more layers, wherein at least one of the one or more layers consists of the polymer composition (PC);

[0085] b) stretching the film in a first direction (i.e. machine direction (MD));

[0086] c) stretching the film in a second direction orthogonal to the first direction (i.e.

[0087] transverse direction (TD));

[0088] d) recovering the resultant biaxially oriented polypropylene (BOPP) film.

[0089] Steps b) and c) may be carried out sequentially or simultaneously.

[0090] The precursor films (PF) of step a) may be produced by any means known to the person skilled in the art. Preferably, the precursor films (PF) are either cast precursor films (CPF), prepared via casting, or blown precursor films (BPF), produced by blowing. Most preferably the precursor films (PF) are cast precursor films (CPF).

[0091] After the precursor film (PF) has been prepared, it is preferably stretched whilst oriented in the machine direction (MD) and the transverse direction (TD) to obtain a biaxially oriented polypropylene (BOPP) film.

[0092] The film may be stretched from 2 to 10 times, preferably 3 to 9 times, its original length. This ratio between the length of the stretched film and the length of the original film is in referred to as the stretching ratio.

[0093] The stretching ratio in the machine and transverse directions may be the same (e.g. 7x7) or different (e.g. 5x9). The total stretching ratio is preferably in the range from 30 to 100,more preferably in the range from 35 to 80, yet more preferably in the range from 40 to 70, most preferably in the range from 45 to 60.

[0094] Preferably, the biaxially oriented polypropylene film according to the present invention may be obtained by orienting the film simultaneously in the machine direction and in the transverse direction, more preferably the simultaneous orientation of the film in the machine direction and in the transverse direction to obtain the biaxially oriented polypropylene film is conducted in a continuous process.

[0095] Alternatively, sequential stretching, first by stretching in machine direction followed by stretching in transverse direction may preferably be employed. The film may be produced in a manner known in the art through sequential stretching ("stenter") systems or simultaneous stretching (e.g. double-bubble and LISIM® - Brueckner Maschinenbau GmbH & Co KG).

[0096] Mixed plastic polypropylene recycling blend

[0097] The mixed-plastic polypropylene recycling blend comprised in the BOPP films according to the present invention has a polypropylene content of at least 92 wt.-%, preferably at least 93 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by Fourier-transform infrared (FTIR) spectroscopy as described herein below. The polypropylene content may be in the range of from 92 to 99.7 wt.-%, preferably from 93 to 99.5 wt.-%, such as from 93 to 99 wt.-%.

[0098] When referred to compositions (such as the mixed-plastic polypropylene recycling blend) and the weight percent of the ingredients comprised therein, it is to be understood that according to the present invention the overall amount of ingredients does not exceed 100 % (±1 % due to rounding).

[0099] If not indicated otherwise, “%” denotes weight percent.

[0100] The mixed-plastic polypropylene recycling blend used in the present invention is generally purer than the mixed plastic of its origin waste. However, usually, the mixed-plastic polypropylene recycling blend still contains at least low contents of the contaminants as described above, based on which it can be distinguished from virgin polypropylenes. For example, the mixed-plastic polypropylene recycling blend may be characterized by a limonene content of at least 0.1 ppm (as determined using solid phase microextraction (HS-SPME-GC-MS) by standard addition).Conventionally the mixed-plastic polypropylene recycling blend used in the present invention may contain one or more of the following components: residual chalk content, residual content of inorganic elements, residual content of paper, residual content of wood, residual content of total free fatty acid, and / or residual content of organic components such as ink binders or tie / barrier layers.

[0101] The mixed-plastic polypropylene recycling blend used in the present invention is of high purity and contains only a very small content of contaminants. According to the present invention, the mixed-plastic polypropylene recycling blend has a sum of contents of contaminants selected from polyamide, polystyrene and chalk of less than 1.0 wt.-%, preferably less than 0.9 wt.-%, and more preferably less than 0.8 wt.-%, such as less than 0.5 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by Fourier-transform infrared (FTIR) spectroscopy as described herein below. The sum of contents of these contaminants may be in the range of from 0 to 1.0 wt.- %, preferably from 0 to 0.9 wt.-%, such as from 0.1 to 0.8 wt.-%.

[0102] According to the present invention, the mixed-plastic polypropylene recycling blend has a content of inclusions of a density of at least 1.1 g / cm3of up to 0.45 vol.-%, preferably up to 0.40 vol.-%, such as in the range of from 0.01 to 0.45 vol.-% (i.e., denoted as “high + low density inclusions"). Further, the content of inclusions of a density of at least 1.1 g / cm3and equal to or lower than 1.53 g / cm3is in the range of from 0.01 to less than 0.40 vol.- %, preferably from 0.01 to 0.35 vol. -%, (i.e., denoted as “low density inclusions"). The contents of inclusions are indicated relative to the total volume of the mixed-plastic polypropylene recycling blend and determined by X-ray Computed Tomography (X-ray CT) as described herein below.

[0103] It is assumed that the inclusions identified in the mixed-plastic polypropylene recycling blend by X-ray Computed Tomography (X-ray CT) are indicative of residual contaminants in the mixed-plastic polypropylene recycling blend. Inclusions of a density of higher than 1.53 g / cm3(i.e., “high density inclusions") are considered to be mostly inorganic contaminants. The inorganic contaminants may comprise compounds of calcium, silicon, titanium and aluminum. Example compounds include calcium carbonate and titanium dioxide. These inorganic contaminants may originate, for example, from additives (e.g., filler) added to the original polypropylene composition prior to the manufacture of the original polypropylene flexible packaging. Alternatively or additionally, the inorganic contaminants may originate from, for example, inks applied to or adjacent the original flexible packaging.Inclusions of a density of at least 1.1 g / cm3and equal to or lower than 1.53 g / cm3(i.e., denoted as “low density inclusions") are considered to be organic contaminants, such as non-polyolefin polymers. These organic contaminants may comprise, or consist essentially of, polyamide and polyethylene terephthalate (PET). Accordingly, the mixed- plastic polypropylene recycling blend used in the present invention has low contents of these residual contaminants.

[0104] For the further processing of the mixed-plastic polypropylene recycling blend, it is important that particularly the content of inclusions of larger sizes is relatively low. It has been found that, by reducing the content of such (in particular, large) inclusions, it is possible to provide a mixed-plastic polypropylene recycling blend that is more useful for the manufacture of films or flexible packaging. While overall levels of contamination may be important, it has been found that the particle size and / or particle size distribution of such inclusions can have an influence on the properties of films produced from the mixed- plastic polypropylene recycling blend. Use of filters during the extrusion process as described herein below may help reducing the content of these inclusions.

[0105] Preferably, the mixed-plastic polypropylene recycling blend has a content of inclusions of a density of at least 1.1 g / cm3having inclusion sizes of more than 50 pm in diameter of less than 0.25 vol.-%, preferably less than 0.20 vol.-%, and / or inclusion sizes of more than 100 pm in diameter of less than 0.15 vol.-%, preferably less than 0.10 vol. -%, relative the total volume of the mixed-plastic polypropylene recycling blend and determined by X-ray Computed Tomography (X-ray CT) as described herein below. For the assessment of the diameter, the longest dimension of each inclusion is considered.

[0106] Preferably, the mixed-plastic polypropylene recycling blend has a content of titanium (Ti) of less than 2000 ppm, preferably less than 1800 ppm, even more preferably less than 1600 ppm, such as less than 1500 ppm, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by X-ray fluorescence (XRF) spectroscopy as described herein below. The content of titanium (Ti) may be in the range of from <LOD to less than 2000 ppm, preferably from <LOD to less than 1800 ppm, even more preferably from <LOD to less than 1600 ppm, such as from 500 to less than 1500 ppm. (<LOD=below limit of detection.)

[0107] Preferably, the mixed-plastic polypropylene recycling blend has a sum of contents of contaminants selected from cadmium (Cd), chromium (Cr), mercury (Hg) and lead (Pb) of less than 5 ppm, preferably less than 4 ppm, such as less than 3 ppm, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by X-ray fluorescence (XRF) spectroscopy as described herein below. The sum of contents ofthese contaminants may be in the range of from 0 to less than 5 ppm, preferably from 0 to less than 4 ppm, such as from 0 to less than 3 ppm. In some embodiments, the sum of contents of these contaminants is 0, i.e., none of these contaminants is detectable in the mixed-plastic polypropylene recycling blend by X-ray fluorescence (XRF) spectroscopy. Preferably, the mixed-plastic polypropylene recycling blend has at least one, preferably all, of the following maximum element contents, relative to the total weight of the mixed- plastic polypropylene recycling blend and determined by X-ray fluorescence (XRF) spectroscopy as described herein below:

[0108] a) a content of aluminum (Al) of less than 130 ppm, preferably less than 120 ppm, such as in the range of from 50 to less than 130 ppm;

[0109] b) a content of calcium (Ca) of less than 1100 ppm, preferably less than 1000 ppm, such as in the range of from 500 to less than 1100 ppm;

[0110] c) a content of iron (Fe) of less than 80 ppm, preferably less than 60 ppm, such as in the range of from 10 to less than 80 ppm;

[0111] d) a content of sulfur (S) of less than 50 ppm, preferably less than 40 ppm, such as in the range of from 10 to less than 50 ppm;

[0112] e) a content of silicon (Si) of less than 480 ppm, preferably less than 460 ppm, such as in the range of from 200 to less than 480 ppm; and

[0113] f) a content of zinc (Zn) of less than 50 ppm, preferably less than 40 ppm, such as in the range of from 10 to less than 50 ppm.

[0114] Preferably, the mixed-plastic polypropylene recycling blend has a content of phosphorus (P) in the range of from 38 to 160 ppm, such as from 45 to 140 ppm, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by X-ray fluorescence (XRF) spectroscopy as described herein below.

[0115] Preferably, the mixed-plastic polypropylene recycling blend has an ash content of not more than 1.0 wt.-%, more preferably not more than 0.75 %, based on the total weight of the mixed plastic polypropylene composition, determined by thermogravimetric analysis (TGA) as described in the experimental section below. The ash content in the mixed- plastic polypropylene recycling blend may be in the range of from 0.1 to 1.0 wt.-%.

[0116] The mixed-plastic polypropylene recycling blend is characterized by good rheological properties. According to the present invention, the mixed-plastic polypropylene recycling blend has a melt flow rate MFR2 in the range of from 3 to 10 g / 10 min, preferably from 4to 9 g / 10 min, such as from 5 to 8 g / 10 min, determined according to ISO 1133, 230 °C, 2.16 kg.

[0117] According to the present invention, the mixed-plastic polypropylene recycling blend has a content of soluble fraction (SF) in the range of from 3.0 to 12.0 wt.-%, preferably from 3.5 to 11.0 wt.-%, more preferably from 4.0 to 10.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by CRYSTEX QC analysis as described herein below.

[0118] According to the present invention, the soluble fraction (SF) has an intrinsic viscosity (IV(SF)) of below 1.1 dl / g, preferably below 1.0 dl / g, such as below 0.9 dl / g, determined by CRYSTEX QC analysis as described herein below. The intrinsic viscosity (IV(SF)) may be in the range of from 0.6 to below 1.1 dl / g, such as from 0.7 to below 1.0 dl / g.

[0119] Preferably, the mixed-plastic polypropylene recycling blend has a content of the crystalline fraction (CF) of at least 88.0 wt.-%, more preferably at least 90.0 wt.-%, such as at least 93.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by CRYSTEX QC analysis as described herein below. The content of the crystalline fraction (CF) may be in the range of from 88.0 to 97.0 wt.-%, preferably from 89.0 to 96.5 wt.-%.

[0120] Preferably, the mixed-plastic polypropylene recycling blend has an ethylene content (C2) of less than 4.5 wt.-%, more preferably less than 4.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by CRYSTEX QC analysis as described herein below. The ethylene content (C2) in the mixed-plastic polypropylene recycling blend may be in the range of from 0.5 to less than 4.5 wt.-%, preferably from 1.0 to less than 4.0 wt.-%.

[0121] Preferably, the crystalline fraction (CF) of the mixed-plastic polypropylene recycling blend has an ethylene content (C2(CF)) of less than 5.0 wt.-%, more preferably less than 4.0 wt.- %, such as less than 3.3 wt.-%, relative to the total weight of the crystalline fraction (CF) and determined by CRYSTEX QC analysis as described herein below. The ethylene content (C2) in the crystalline fraction (CF) may be in the range of from 0.5 to less than 5.0 wt.-%, preferably from 1.0 to less than 4.0 wt.-%.

[0122] Preferably, the soluble fraction (SF) of the mixed-plastic polypropylene recycling blend has an ethylene content (C2(SF)) of less than 15.0 wt.-%, more preferably less than 13.0 wt.-%, such as less than 10.0 wt.-%, relative to the total weight of the soluble fraction (SF) and determined by CRYSTEX QC analysis as described herein below. The ethylenecontent (C2) in the soluble fraction (SF) may be in the range of from 5.0 to less than 15.0 wt.-%, preferably from 6.0 to less than 13.0 wt.-%.

[0123] It is specifically preferred that the mixed-plastic polypropylene recycling blend used in the present invention has

[0124] a) an ethylene content (C2) in the mixed-plastic polypropylene recycling blend of less than 4.5 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend;

[0125] b) an ethylene content of the soluble fraction (C2(SF)) of less than 15.0 wt.-%, relative to the total weight of the soluble fraction (SF); and

[0126] c) an ethylene content of the crystalline fraction (C2(CF)) of less than 3.3 wt.-%, relative to the total weight of the crystalline fraction (CF), wherein the content of the crystalline fraction (CF) in the mixed-plastic polypropylene recycling blend is at least 88.0 wt.-%, preferably at least 93.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend.

[0127] The mixed-plastic polypropylene recycling blend has very advantageous mechanical properties. According to the invention, the mixed-plastic polypropylene recycling blend preferably has a flexural modulus in the range of from 1050 to 1350 MPa, more preferably from 1070 to 1300 MPa, determined according to ISO 178 (method A, type B specimen). Preferably, the mixed-plastic polypropylene recycling blend has an Eta(0.05rad / s), 200°C in the range of from 3000 to 4500 Pa.s, more preferably from 3500 to 4400 Pa.s.

[0128] Preferably, the mixed-plastic polypropylene recycling blend has an Eta(300rad / s), 200°C in the range of from 250 to 350 Pa.s, more preferably from 280 to 330 Pa.s.

[0129] Preferably, the mixed-plastic polypropylene recycling blend has a Shear Thinning Factor (STF), Eta(0.05) / Eta(300), in the range of from 9.5 to 16.0, more preferably from 10.0 to 15.0.

[0130] The Eta values are determined as described herein below.

[0131] It is specifically preferred that the mixed-plastic polypropylene recycling blend used in the present invention has

[0132] a) an Eta(0.05rad / s), 200°C in the range of from 3000 to 4500 Pa.s,

[0133] b) an Eta(300rad / s), 200°C in the range of from 250 to 350 Pa.s, and

[0134] c) a Shear Thinning Factor (STF), Eta(0.05) / Eta(300), in the range of from 9.5 to 16.0.It is further preferred that the mixed-plastic polypropylene recycling blend used in the present invention is an extruded, such as melt-extruded, material. Preferably, the melt- extruded mixed-plastic polypropylene recycling blend is present in the form of pellets. The mixed-plastic polypropylene recycling blend, particularly as melt-extruded material, may comprise additives (Ad), e.g., selected from additives known in the art, preferably selected from the group consisting of antioxidants, stabilizers, fillers, colorants, nucleating agents, antistatic agents, and mixtures thereof. Such additives are generally commercially available and are described, for example, in “Plastic Additives Handbook”, pages 871 to 873, 5th edition, 2001 of Hans Zweifel. Generally, additives are contained in a polymer blend in a content of up to 5 wt.-%, relative to the total weight of the polymer.

[0135] The mixed plastic polypropylene recycling blend may preferably be obtained from a transparent fraction of a mixed polypropylene post consumer waste (PCW) feedstock. Virgin polypropylene (v-PP)

[0136] The BOPP films of the present invention may preferably comprise a PP composition comprising a blend of the mixed-plastic polypropylene recycling blend and of a virgin polypropylene (PP). The virgin PP is preferably selected from the group consisting of heterophasic polypropylenes, polypropylene random copolymers or propylene homopolymers. Preferred examples of suitable virgin PP are heterophasic propylene¬ ethylene copolymers, propylene homopolymers (h-PP), or propylene-ethylene random copolymers.

[0137] The virgin polypropylene may preferably have a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 0.1 to 15.0 g / 10 min, more preferably in the range from 1.5 to 10.0 g / 10 min, most preferably in the range from 2.5 to 4.0 g / 10 min.

[0138] The virgin polypropylene may preferably have a melting temperature (Tm), determined according to ISO 11357, as described in the experimental part below, in the range from 155 to 172 °C, more preferably in the range from 158 to 168 °C, most preferably in the range from 160 to 165 °C.

[0139] It is preferred that the virgin polypropylene (v-PP) is a heterophasic propylene copolymer (HECO), such as a heterophasic propylene-ethylene copolymer, or a propylene homopolymer (h-PP).

[0140] If the virgin polypropylene (v-PP) is a heterophasic propylene copolymer (HECO), such as a heterophasic propylene-ethylene copolymer, it is preferred that the matrix componentof the heterophasic propylene copolymer (HECO) is free from 2,1 -regiodefects, as determined by quantitative13C-NMR spectroscopy.

[0141] If the virgin propylene polymer (v-PP) is a heterophasic propylene copolymer (HECO), such as a heterophasic propylene-ethylene copolymer, it is preferred that the matrix component of the heterophasic propylene copolymer (HECO) has a pentad isotacticity [mmmm], as determined by quantitative13C-NMR spectroscopy, in the range from 90.0 to 98.0%.

[0142] These features are indicative that the heterophasic propylene copolymer (HECO) has been produced using a Ziegler-Natta catalyst, in contrast to a single-site catalyst, such as a metallocene catalyst.

[0143] It is particularly preferred that the virgin propylene polymer (v-PP) is a propylene homopolymer (h-PP).

[0144] It is preferred that the propylene homopolymer (h-PP) is free from 2,1 -regiodefects, as determined by quantitative13C-NMR spectroscopy.

[0145] It is preferred that the propylene homopolymer (h-PP) has a pentad isotacticity [mmmm], as determined by quantitative13C-NMR spectroscopy, in the range from 92.0 to 98.0%. These features are indicative that the propylene homopolymer (h-PP) has been produced using a Ziegler-Natta catalyst, in contrast to a single-site catalyst, such as a metallocene catalyst.

[0146] It is preferred that the propylene homopolymer (h-PP) has a molecular weight distribution (Mw / Mn), determined according to gel permeation chromatography, as described in the experimental part below, in the range from 4.0 to 9.0, more preferably in the range from 4.0 to 8.0, most preferably in the range from 4.5 to 7.5.

[0147] It is preferred that the propylene homopolymer (h-PP) has a xylene cold soluble (XCS) content, determined according to ISO 16152, as described in the experimental part below, in the range from 0.0 to 5.0 wt.-%, more preferably in the range from 0.0 to 4.0 wt.-%, most preferably in the range from 0.0 to 3.5 wt.-%.

[0148] In the biaxially oriented polypropylene film according to the present invention the polypropylene composition (PC) may preferably comprise:

[0149] a) from 20.0 to 100.0 wt.-%, relative to total weight of the polypropylene composition (PC), of said mixed-plastic polypropylene recycling blend, and

[0150] b) from 0.0 to 80.0 wt.-%, relative to total weight of the polypropylene composition (PC), of said virgin propylene polymer (v-PP).Thus, the blend of the mixed-plastic polypropylene recycling blend and of the virgin PP may preferably comprise the mixed-plastic polypropylene recycling blend and the virgin PP in a weight ratio of from 100:0 to 20:80, more preferably 90:10 to 20:80, preferably, in a weight ratio from 80:20 to 30:70.

[0151] Preparation of the mixed-plastic polypropylene recycling blend

[0152] The mixed-plastic polypropylene recycling blend is characterized by the beneficial properties as described above, in particular high purity. These beneficial properties are obtained by the preparation of the mixed-plastic polypropylene recycling blend by a mechanical recycling process comprising the following steps:

[0153] a) providing a precursor mixed-plastic recycling stream (A), wherein the precursor mixed-plastic recycling stream (A) comprises at least 70 wt.-% of flexible polymer articles, relative to the total weight of the precursor mixed-plastic recycling stream (A);

[0154] b) separating the precursor mixed-plastic recycling stream (A) according to size to prepare a separated mixed-plastic recycling stream (B) having only articles with a longest dimension in the range of from 30 to 400 mm;

[0155] c) removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C);

[0156] d) sorting the purer separated mixed-plastic recycling stream (C), preferably by means of one or more optical sorters, according to polymer type and transparency, and optionally also according to color and / or reflectance, and selecting a polypropylene-rich stream of high transparency, thereby generating a sorted polypropylene recycling stream (D);

[0157] wherein steps c) and d) can be in any order, and if step c) is subsequent to step d), the sorted polypropylene recycling stream (D) is obtained after step c);

[0158] e) optionally, conducting a quality-control (1) step to determine the quality of the sorted polypropylene recycling stream (D), based on the following parameters: e1 ) the content of flexible polyethylene articles,

[0159] e2) the content of flexible multi-material multi-layer articles,

[0160] e3) the content of transparent flexible polypropylene articles,e4) the content of metallized flexible polypropylene articles,

[0161] e5) the content of colored flexible polypropylene articles, and

[0162] e6) optionally the content of flexible polypropylene articles,

[0163] and allowing the sorted polypropylene recycling stream (D) to proceed to step f) if pre-determined conditions for these parameters are fulfilled, thereby generating a quality-controlled (1) polypropylene recycling stream (E1);

[0164] otherwise, if the pre-determined conditions are not fulfilled:

[0165] resending the sorted polypropylene recycling stream (D) to step c) or d), and reconducting steps c) and / or d) and optionally step e) on the sorted polypropylene recycling stream (D), thereby generating a quality-controlled (1) polypropylene recycling stream (E2); or

[0166] combining the sorted polypropylene recycling stream (D) with a polypropylene recycling stream (X) that fulfills the pre-determined conditions, thereby generating a quality-controlled (1) polypropylene recycling stream (E3);

[0167] f) size-reducing the quality-controlled (1) polypropylene recycling stream (E), being stream (E1) and / or (E2) and / or (E3), or the sorted polypropylene recycling stream (D), preferably in the presence of water or an aqueous solution, to form a flaked polypropylene recycling stream (F);

[0168] g) washing the flaked polypropylene recycling stream (F) with an aqueous washing solution, removing the aqueous washing solution and optionally any material not floating on the surface of the aqueous washing solution, and rinsing with water, to obtain a washed polypropylene recycling stream (G);

[0169] h) optionally, drying the washed polypropylene recycling stream (G), thereby obtaining a dried polypropylene recycling stream (H);

[0170] i) separating the dried polyolefin recycling stream (H) or the washed polypropylene recycling stream (G) into a light fraction polypropylene recycling stream and a heavy fraction recycling stream, and selecting the light fraction polypropylene recycling stream (I);

[0171] j) conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I), based on the following parameters:

[0172] all of parameters j1) to j3):

[0173] j1 ) the content of transparent flexible polypropylene flakes,j2) the content of colored and non-transparent flexible polyethylene flakes, and j3) the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes; and / or

[0174] all of parameters j4) to j6):

[0175] j4) the content of transparent flexible polypropylene flakes,

[0176] j5) the content of polypropylene, and

[0177] j6) the content of polyethylene,

[0178] and allowing the light fraction polypropylene recycling stream (I) to proceed to step k) if pre-determined conditions for these parameters are fulfilled, thereby generating a quality-controlled (2) polypropylene recycling stream (J1), otherwise, if the pre-determined conditions are not fulfilled, combining the light fraction polypropylene recycling stream (I) with a polypropylene recycling stream (Y) that fulfills the pre-determined conditions, thereby generating a quality- controlled (2) polypropylene recycling stream (J2);

[0179] k) melt-extruding, and preferably pelletizing, the quality-controlled (2) polypropylene recycling stream (J), being stream (J1) and / or (J2), preferably wherein additives (Ad) are added in the melt state, to form an extruded, and preferably pelletized, polypropylene recycling product (K); and

[0180] l) optionally, aerating, preferably at an air temperature in the range of from 100 to 150 °C, the extruded, and preferably pelletized, polypropylene recycling product (K) to remove volatile organic compounds, thereby generating an aerated extruded, preferably pelletized, polypropylene recycling product (L), and thus providing the mixed-plastic polypropylene recycling blend.

[0181] Step a) of the process involves the provision of a precursor mixed-plastic recycling stream (A), wherein the precursor mixed-plastic recycling stream (A) comprises at least 70 wt.-% of flexible polymer articles, relative to the total weight of the precursor mixed-plastic recycling stream (A).

[0182] A “precursor mixed-plastic recycling stream (A)’’ denotes a stream of mixed plastic, as defined above, comprising plastic objects originating from waste, preferably post¬ consumerwaste, i.e. , having completed at least a first use cycle (or life cycle) and having already served their first purpose. Generally, it contains polyolefins and other components, such as polystyrenes, polyamides, polyesters, wood, paper, limonene,aldehydes, ketones, fatty acids, inorganic materials, organic components, and / or long¬ term decomposition products of stabilizers, in some amounts.

[0183] The precursor mixed-plastic recycling stream (A) comprising at least 70 wt.-% of flexible polymer articles may be provided by sorting out from a stream of mixed plastic (e.g., comprising rigid and flexible polymer articles) or from municipal solid waste. The precursor mixed-plastic recycling stream (A) may comprise flexible polypropylene articles and flexible non-polypropylene articles, such as flexible polyethylene articles (e.g., LLDPE- and LDPE-containing articles) in amounts originating from the mixed plastic. For example, the ratio of flexible polypropylene articles to flexible polyethylene articles in the precursor mixed-plastic recycling stream (A) may be from 0.1:1 to 50:1, preferably it is from 0.25:1 to 25:1.

[0184] For example, the precursor mixed-plastic recycling stream (A) may comprise a high content (e.g., at least 70 wt.-%) of polypropylene-containing films, such as films used in primary (e.g., food) and secondary packaging applications.

[0185] The form in which the precursor mixed-plastic recycling stream (A) is provided is not important; however, it is important that the articles present in the precursor mixed-plastic recycling stream (A) are not stuck together during the subsequent steps of the process. If required, a debaling step may be carried out. Methods for debaling are generally known in the art, and include e.g., manual debaling via a crane and debaling via an automatic bale opener (debaler).

[0186] Step b) of the process involves separating the precursor mixed-plastic recycling stream (A) according to size to prepare a separated mixed-plastic recycling stream (B) having only articles with a longest dimension in the range of from 30 to 400 mm, preferably from 35 to 380 mm and more preferably from 40 to 350 mm.

[0187] The person skilled in the art would be aware of multiple ways in which the separating of step b) could be achieved. For example, the separating of step b) is carried out by sieving and / or screening the articles in the precursor mixed-plastic recycling stream (A) for the required sizes.

[0188] Step c) of the process involves removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C). Metal particles may be articles or parts thereof contained in the original waste material, and thus often contained in the precursor mixed-plastic recycling stream (A). Removal of metal particles from the separated mixed-plastic recycling stream (B) is important in order to protect the process equipment from destruction by remaining metal particles.In addition, flexible polymer articles comprising magnetic metallic layers may be removed by this step as well.

[0189] The metal particle removal of step c) may be conducted by any means known in the art for metal removal. Usually, magnets and EDDY current separators are employed in these methods. Preferably, an over-belt magnet is used, wherein the separated mixed-plastic recycling stream (B) is passed under an over-blet magnet.

[0190] Step c) may be conducted before or after the sorting step d). It is important that this step is performed at least one time in the process, however, it may be performed several times. Step d) of the process involves sorting the purer separated mixed-plastic recycling stream (C), preferably by means of one or more optical sorters, according to polymer type and transparency, and optionally also according to color and / or reflectance, and selecting a polypropylene-rich stream of high transparency, thereby generating a sorted polypropylene recycling stream (D). As described above, steps c) and d) can be conducted in any order. If step c) is subsequent to step d), the sorted polypropylene recycling stream (D) is obtained after step c).

[0191] The presence of sorting step d) enables the preparation of high-quality recycled products, regardless of the quality of the feedstock material. It is well known that feedstock materials can greatly vary in quality, with regard to polyolefin content and foreign material contamination, which is largely dependent on the source of the feedstock material (i.e. the source of the precursor mixed-plastic recycling stream (A)).

[0192] Generally, it is to be understood that the sorting does not provide streams of articles having 100 % of the characteristic according to which the sorting is carried out. In contrast, the sorting generally occurs for articles predominantly having the required characteristic. The term “predominantly’ generally means more than 50 % of an article has the required characteristic.

[0193] By sorting according to polymer type, the majority of articles that contain polymers other than polypropylene and / or of articles which do not contain any polypropylene (such as paper articles) is removed from the stream, leading to a polypropylene-rich stream. This means that articles predominantly containing polypropylene remain in the stream.

[0194] The sorting method according to polymer type is not particularly limited. Preferably, the sorting according to polymer type of step d) is carried out using one or more optical sorters. In the context of the present description, the term “optical sorted denotes a sorting unit that uses any form of electromagnetic (EM)-radiation (visible or non-visible) to differentiate the articles of the purer separated mixed-plastic recycling stream (C).Suitable methods for sorting the recycling stream according to polymer type include near-IR spectroscopic analysis, mid-IR spectroscopic analysis, high-speed laser spectroscopic analysis, Raman spectroscopic analysis, Fourier-transform infrared (FTIR) spectroscopic analysis. Particularly preferred is near-IR spectroscopic analysis.

[0195] Generally, the sorting of step d) can be achieved through simple sorting algorithms, wherein the optical sensor(s) are programmed to assess which articles should be selected or rejected based on simple binary considerations. Alternatively, more complex Al-based systems can be used to achieve a more precise sorting, wherein the optical sorter can recognize certain articles, possibly having certain branding, and from this recognition would know what polymers are contained in said article without having to manually determine the polymer content (e.g., by IR-spectroscopic analysis).

[0196] By sorting according to transparency, the majority of non-transparent articles is removed from the stream, leading to a stream of high transparency. This means that predominantly transparent articles remain in the stream.

[0197] Generally, “transparency’ is the quality that an object has when one can see through it. Thus, this wording describes the clearness of an object. Accordingly, transparent articles may be slightly colored or slightly translucent, as long as one can see through them. Regarding the composition of transparent articles, it is assumed that they may contain only small amounts of foreign materials such as metals or other pigments (e.g., titanium oxide, iron oxides, etc.) such that they may be lightly colored or slightly translucent.

[0198] Transparency may be defined by the RGBA color model, wherein RGBA stands for red green blue alpha, and alpha is an indicator of transparency. A value of 0 is defined as fully transparent, while a value of 1 stands for fully opaque. Based on the RGBA color model, the wording “transparent denotes an object that has an alpha value of less than 0.3, preferably less than 0.2, such as less than 0.1.

[0199] Alternatively, transparency may be defined via clarity, haze and / or luminous transmittance as determined according to ASTM D1003 (based on a cast film test specimen of 50 pm in thickness). An article of more than 60 % clarity, less than 20 % haze and / or less than 20 % diffuse luminous transmittance would be considered a transparent article.

[0200] The sorting method according to transparency is not particularly limited. Usually, methods and devices used for color sorting may be used for sorting according to transparency. Suitable methods for color sorting include optical sorters, such as camera systems (operating in the visible range of the EM-spectrum), visible reflectance spectroscopy, near-IR spectroscopic analysis, mid-IR spectroscopic analysis, and high-speed laserspectroscopic analysis. These methods can be used for the sorting according to transparency of step d).

[0201] The sorting according to polymer type and according to transparency may be carried out in any order or concurrently.

[0202] After these sorting sub-steps, a polypropylene-rich stream of high transparency is selected for the further process steps.

[0203] The sorting step d) may further comprise sorting according to color and / or reflectance. Preferably, the sorting step d) further comprises sorting according to color and reflectance. Purity of the final product can generally be improved with the number of sorting sub-steps. These additional sorting sub-steps allow to reach an article stream with higher transparency. The sorting according to color may remove colored articles, such as e.g., lightly colored transparent articles or predominantly transparent articles containing small amounts of colored parts, labels and coatings etc., if these articles are intended to be removed for improved product quality. The sorting according to reflectance may remove reflecting articles, such as articles comprising a metal layer. A process comprising these sub-steps may provide a product with an even higher purity. Many labels and coatings may be removed by washing; however, in particular metals and inks (especially if contained as layers) may be more complicated to remove.

[0204] Preferably, any of these additional sub-steps can be carried out by optical sorters for color sorting as described above. It is preferred that the sorting according to reflectance is carried out by an optical sorter based on infrared-attenuated total reflectance (IR-ATR) spectroscopic analysis and / or camera systems (operating in the visible range of the EM spectrum). The first-mentioned method is a specialized method wherein the surface properties of the piece are determined (typically the data obtained by such a method describes the outermost 2 pm of a polymer piece, hence the surface properties). The latter-mentioned method can achieve the sorting by any form of recognition algorithm, wherein the optical sensor is programmed to assess which articles should be selected or rejected based on simple binary considerations. Alternatively, more complex Al-based systems can be used to achieve a more precise sorting, in particular when a certain brand of packaging is recognised and the composition of said packaging is known.

[0205] Step e) of the process involves conducting a quality-control (1) step to determine the quality of the sorted polypropylene recycling stream (D). Step e) is an optional step of the process.The quality-control (1) step, if present, serves to determine the quality of the sorted polypropylene recycling stream (D), and particularly the efficiency of step d).

[0206] The quality of the sorted polypropylene recycling stream (D) is based on the following parameters:

[0207] e1 ) the content of flexible polyethylene articles,

[0208] e2) the content of flexible multi-material multi-layer articles,

[0209] e3) the content of transparent flexible polypropylene articles,

[0210] e4) the content of metallized flexible polypropylene articles,

[0211] e5) the content of colored flexible polypropylene articles, and

[0212] e6) optionally, the content of flexible polypropylene articles.

[0213] If step e) is performed, the sorted polypropylene recycling stream (D) is allowed to proceed to step f) only if pre-determined conditions for these parameters are fulfilled.

[0214] Preferably, these pre-determined conditions are:

[0215] e1 ) the content of flexible polyethylene articles is below 5 wt.-%,

[0216] e2) the content of flexible multi-material multi-layer articles is below 5 wt.-%, e3) the content of transparent flexible polypropylene articles is more than 35 wt.-%, e4) the content of metallized flexible polypropylene articles is below 6 wt.-%, e5) the content of colored flexible polypropylene articles is below 8 wt.-%, and e6) optionally, the content of flexible polypropylene articles is at least 80 wt.-%, all contents being relative to the total weight of the sorted polypropylene recycling stream (D).

[0217] Parameters e1) to e6) are evaluated based on the following features:

[0218] The wording “flexible polyethylene articles" of parameter e1) refers to flexible articles comprising at least 75 wt.-% of polyethylene.

[0219] The wording “flexible multi-material multi-layer articles" of parameter e2) refers to flexible articles comprising at least two layers of different materials. The different layers may be of non-polypropylene polymers or propylene and non-polypropylene polymers, or mixed polymers, typically they are of non-polypropylene polymers. Metallized materials, even if in the form of multi-layer, do not fall under the wording of parameter e2) as they are already encompassed by parameter e4).The wording “transparent flexible polypropylene articles" of parameter e3) refers to flexible articles comprising at least 75 wt.-% of polypropylene, and wherein at least 90 % of the area of the article (the area being one surface of the flexible article) are transparent, the transparent area having less than 20 % haze (determined according to ASTM D1003, and based on a cast film test specimen of 50 pm in thickness). Flexible articles, wherein only up to 25 % of the area of the article are transparent, are referred to as non-transparent articles. Flexible articles often contain ink (white and / or colored) on their surface that prevents transparency. Thus, flexible articles, wherein between 25 and 90 % of the area of the article are transparent, are referred to as partly colored flexible articles (these articles typically have 10 to 75 % of the area of the article covered by colored ink).

[0220] The wording “metallized flexible polypropylene articles" of parameter e4) refers to flexible articles comprising at least 75 wt.-% of polypropylene and any metal component in any amount. Usually, the metal components may be in the form of metal layers or metal inks on the flexible polypropylene articles.

[0221] The wording “colored flexible polypropylene articles" of parameter e5) refers to flexible articles comprising at least 75 wt.-% of polypropylene, and wherein at least 75 % of the area of the article (the area being one surface of the flexible article) are colored, i.e., typically has a colored ink on the surface. Color may be determined based on the RDB system, wherein pure white has each of R, D and B values of 255. Accordingly, a colored material generally has at least one of the R, D and B values of less than 250. Flexible articles, wherein between 10 and 75 % of the area of the article are colored, are referred to as partly colored flexible articles. Flexible articles, wherein only up to 10 % of the area of the article are colored, are referred to as non-colored articles.

[0222] The wording “flexible polypropylene articles" of parameter e6) refers to flexible articles comprising at least 75 wt.-% of polypropylene.

[0223] Preferably, the quality of the sorted polypropylene recycling stream (D) in step e) (i.e., in each of steps e1) to e6)) is determined by sorting by hand following a visual inspection and / or by optical imaging via near-IR spectroscopic analysis, near-IR / VIS spectroscopic analysis or a camera system operating in the visible range of the EM-spectrum, on a sample from the sorted polypropylene recycling stream (D).

[0224] Accordingly, the determination of parameters in the quality-control (1) step may be carried out with the use of an optical detector or without the use of an optical detector by sorting by hand following a visual inspection. Sorting by hand by a skilled person is very reliable and able to identify articles that may not be found by the optical detector. Sorting by hand following a visual inspection operates on the same principles as the use of camerasystems in combination with either simple recognition algorithms or more complex Al- based systems, with the latter expected to predominate, as Al recognition improves yet further.

[0225] The sorted polypropylene recycling stream (D) is allowed to proceed to step f) if the pre¬ determined conditions for the above parameters are fulfilled, thereby generating a quality- controlled (1) polypropylene recycling stream (E1).

[0226] Otherwise, if the pre-determined conditions are not fulfilled,

[0227] 1) the sorted polypropylene recycling stream (D) is resent to step c) or d), and steps c) and / or d) and optionally step e) are reconducted on the sorted polypropylene recycling stream (D), thereby generating a quality-controlled (1) polypropylene recycling stream (E2); or

[0228] 2) the sorted polypropylene recycling stream (D) is combined with a polypropylene recycling stream (X) that fulfills the pre-determined conditions, thereby generating a quality-controlled (1) polypropylene recycling stream (E3).

[0229] In option 2), the sorted polypropylene recycling stream (D) is preferably combined with a polypropylene recycling stream (X) in a ratio of the sorted polypropylene recycling stream (D) to the polypropylene recycling stream (X) in the range of from 0.05:1 to 5:1, preferably from 0.1:1 to 2:1, such as from 0.5:1 to 1:1. The ratio will typically depend on the purity of the sorted polypropylene recycling stream (D) and the purity of the polypropylene recycling stream (X), in particular, based on the pre-determined conditions e1) to e5), and optionally e6) as specified above. Preferably, the sorted polypropylene recycling stream (D) is combined with a polypropylene recycling stream (X) in such a ratio that the generated quality-controlled (1) polypropylene recycling stream (E3) fulfills the conditions e1) to e5), and optionally e6), as defined above.

[0230] In this way, the quality of the sorted polypropylene recycling stream (D) may be improved. Step f) of the process involves size-reducing the quality-controlled (1) polypropylene recycling stream (E) or the sorted polypropylene recycling stream (D), preferably in the presence of water or an aqueous solution, to form a flaked polypropylene recycling stream (F).

[0231] The quality-controlled (1) polypropylene recycling stream (E) may be the quality-controlled (1) polypropylene recycling stream (E1) and / or the quality-controlled (1) polypropylene recycling stream (E2) and / or the quality-controlled (1) polypropylene recycling stream (E3).The size-reducing step f) may be carried out as a wet process or a dry process by any method known to the person skilled in the art. Suitable methods involve milling and / or grinding, particularly wet-milling and / or wet-grinding, the quality-controlled (1) polypropylene recycling stream (E) or the sorted polypropylene recycling stream (D). An alternative method involves shredding the quality-controlled (1) polypropylene recycling stream (E) or the sorted polypropylene recycling stream (D). It is particularly preferred that the size-reducing step f) is a wet-grinding step.

[0232] The size-reducing step f) produces a flaked polypropylene recycling stream (F). The flakes of the flaked polypropylene recycling stream (F) preferably have a surface area in the range of from 50 to 2500 mm2, more preferably from 100 to 1600 mm2and most preferably from 150 to 900 mm2. In the context of the present description, the flake surface area is defined as the surface area of one of the faces of a flake. This surface area is approximately half of the total surface area of the flake, which has two such faces in addition to a very small amount of surface area coming from the edges of the flake. Accordingly, the total surface area of the flake can range to more than 5000 mm2.

[0233] Step g) of the process involves washing the flaked polypropylene recycling stream (F) with an aqueous washing solution, removing the aqueous washing solution and optionally any material not floating on the surface of the aqueous washing solution, and rinsing with water, to obtain a washed polypropylene recycling stream (G).

[0234] The washing of step g) may comprise one or more washing sub-steps. The nature of the washing sub-step(s) is not limited. However, it is preferred that the one or more washing sub-steps of step g) are continued until the majority of, preferably all, colored areas (such as, e.g., inks) have been removed from the flakes of the flaked polypropylene recycling stream (F).

[0235] The primary contaminant in flexible polypropylene articles is ink. Coloration of flexible polypropylene articles is rarely performed via the addition of one or more pigments within the polypropylene-based compositions used to make the flexible polypropylene articles, as would usually be the case for rigid polymer articles, but rather it is performed via the application of ink layers onto the surface of the flexible polypropylene articles. With few exceptions, the polypropylene-based compositions used to produce flexible polypropylene articles are generally either natural (i.e., no pigment present) or white. In the case of white polypropylene compositions, the white appearance is typically the result of cavitation, often related to the presence of calcium carbonate. Cavitation is often combined with white pigments, typically with titanium dioxide. It is intended by the present process to provide a very pure unpigmented recyclate.It is preferred that at least one of the washing sub-steps of step g) uses alkaline conditions in the aqueous washing solution and is conducted at a temperature in the range of from 40 to 95 °C. If more than one washing sub-step are used in step g), it is preferred to use alkaline conditions in the aqueous washing solution and, independently, a temperature in the range of from 20 to 95 °C in all washing sub-steps, wherein at least one washing sub¬ step has a temperature in the range of from 40 to 95 °C.

[0236] The choice of alkaline conditions in the aqueous washing solution is not particularly limited; however, it is preferred that the aqueous washing solution has a pH in the range of from 8.0 to 14.0, more preferably from 10.0 to 14.0 and most preferably from 12.0 to 14.0.

[0237] Preferably, the aqueous washing solution is an aqueous solution of a base selected from the group consisting of calcium hydroxide, potassium hydroxide, magnesium hydroxide, lithium hydroxide, sodium bicarbonate, sodium hydroxide and mixtures thereof. Most preferably, the aqueous washing solution is an aqueous solution of sodium hydroxide. It is preferred that the amount of the base in the aqueous washing solution is in the range of from 0.05 to 10.00 wt.-%, more preferably from 0.10 to 7.00 wt.-% and most preferably from 0.50 to 5.00 wt.-%, relative to the total weight of the aqueous washing solution. Aqueous washing solutions, preferably alkaline solutions, suitable for use in the washing sub-step(s) of step g) may comprise a detergent in an amount in the range of from 0.1 wt.-% to 3.0 wt.-%, preferably from 0.1 wt.-% to 1.0 wt.-%, relative to the total weight of the aqueous washing solution.

[0238] The detergent may be commercially available detergent mixtures or may be composed in any way known to the person skilled in the art. Suitable detergents include TUBIWASH SKP, TUBIWASH GFN, TUBIWASH EYE and TUBIWASH TOP, commercially available from CHT, KRONES colclean AD 1004, KRONES colclean AD 1002 and KRONES colclean AD 1008 from KIC KRONES, and P3-stabilon WT, P3 stabilon AL from ECOLAB Ltd.

[0239] It is further preferred that the washing of step g) involves the application of agitation during the washing sub-step(s), wherein the kind of agitation may be selected from the group consisting of mechanical mixing, ultrasonic treatment, mechanical grinding or pump around loop. Agitation helps to expose the flakes in the recycling stream to fresh washing solution, thus ensuring that the process is not hindered through the buildup of contaminants (e.g., ink) in the immediate vicinity of the flake.Preferably, the washing sub-step(s) of step g) is / are carried out for a duration in the range of from 5 to 120 min, more preferably from 10 to 60 min and most preferably from 10 to 30 min.

[0240] Preferably, at least one washing sub-step of step g) is carried out at a temperature in the range of from 40 to 95 °C, preferably from 55 to 95 °C, more preferably from 60 to 85 °C and most preferably from 60 to 80 °C. The temperature of the washing sub-step(s) may be reached without the input of thermal energy (e.g., if already pre-heated water from another step is used) or may by adjusted by heating the aqueous washing solution.

[0241] Preferably , at least one of the washing sub-steps of step g) is carried out with an aqueous washing solution having a pH in the range of from 8.0 to 14.0, and comprising from 0.50 to 5.00 wt.-% of a base, preferably being NaOH, and from 0.1 wt.-% to 1.0 wt.-% of detergent (both contents being relative to the total weight of the aqueous washing solution), at a temperature in the range of from 40 to 95 °C and for a duration in the range of from 5 to 120 min and during agitation.

[0242] It is particularly preferred that step g) comprises, in the given order, the following sub¬ steps if one washing sub-step is applied (preferably under the conditions of the preferred embodiments):

[0243] g1) washing the flaked polypropylene recycling stream (F) with an aqueous washing solution at a controlled temperature for a controlled duration, thereby generating a first suspended polypropylene recycling stream (G1);

[0244] g2) removing the aqueous washing solution and optionally any material not floating on the surface of the aqueous washing solution, thereby generating a washed polypropylene recycling stream (G2); and

[0245] g3) rinsing the washed polypropylene recycling stream (G2) with water, to obtain a rinsed washed polypropylene recycling stream (G3) that is the washed polypropylene recycling stream (G).

[0246] Generally, by removing the aqueous washing solution, inks and other contaminants (such as adhesives and / or paper labels) are removed from the recycling stream. In the context of the present description, the wording “removing the aqueous washing solution" denotes that at least part of the aqueous washing solution is removed, i.e. , it is not required that the aqueous washing solution is removed completely.

[0247] Material not floating on the surface of the aqueous washing solution may also be removed with the aqueous washing solution, by a so-called float / sink separation. This material would be any foreign material having a density of greater than 1.00 g / cm3Without wishing to be bound by theory, it is believed that the inclusion of a float / sink separation step directly after washing step g) is extremely beneficial for removing as much foreign material as possible. Later steps in the process, such as aerating step I) or drying step h) may result in foreign material that has been detached from the polypropylene flakes but has not been removed to re-adhering to the polypropylene flakes. This can result in contamination of the final recycled product.

[0248] By rinsing with water, traces of the aqueous washing solution remaining on the surface of the flakes and therewith any residual contamination (e.g., ink) contained in the aqueous washing solution are intended to be removed. The rinsing sub-step preferably has a duration of less than 5 min.

[0249] Particularly preferred, step g) is carried out with the following sub-steps:

[0250] g1a) washing the flaked polyolefin recycling stream (F) with a first aqueous washing solution (W1) having a pH in the range of from 8.0 to 14.0, preferably from 10.0 to 14.0, and in particular from 12.0 to 14.0, without the input of thermal energy, thereby generating a first suspended polypropylene recycling stream (G1a); g2a) removing the first alkaline aqueous washing solution (W1) from the first suspended polyolefin recycling stream (G1a) to obtain a first washed polypropylene recycling stream (G2a);

[0251] g1 b) washing the first washed polyolefin recycling stream (G2a) with a second aqueous washing solution (W2) having a pH in the range of from 12.0 to 14.0 thereby generating a second suspended polypropylene recycling stream (G1b), wherein sufficient thermal energy is put into the system to raise the temperature to a temperature in the range of from 55 to 95 °C, preferably from 60 to 85 °C, and more preferably from 60 to 80 °C during the washing;

[0252] g2b) removing the washing solution (W2) and any material not floating on the surface of the second aqueous washing solution from the second suspended polypropylene recycling stream (G2a) to obtain a second washed polypropylene recycling stream (G2b); and

[0253] g3) rinsing the second washed polypropylene recycling stream (G2b) with water to obtain a rinsed second washed polypropylene recycling stream (G3), wherein the rinsed second washed polypropylene recycling stream (G3) corresponds to the washed polyolefin recycling stream (G).

[0254] It is preferred that the temperature of the first aqueous washing solution (W1) during sub¬ step g1a) is less than 70 °C, more preferably less than 60 °C, most preferably less than50 °C, such as less than 40 °C. For example, washing sub-step g1a) may be carried out at a temperature in the range of from 20 °C to less than 60 °C, preferably from 20 °C to less than 50 °C.

[0255] The first and second aqueous washing solutions (W1 ) and (W2) may comprise a detergent in an amount in the range of from 0.1 wt.-% to 3.0 wt.-%, preferably from 0.1 wt.-% to 1.0 wt.-%, relative to the total weight of the first aqueous washing solution (W1) or (W2), respectively. The detergent may be selected from any of the detergents described above. Sub-steps g1a) and gib) are preferably carried out during agitation, particularly through ultrasonic treatment, and for a duration of 5 to 120 min.

[0256] Without wishing to be bound by theory, it is believed that the inclusion of a float / sink separation step directly after the high temperature washing sub-step gib) is extremely beneficial for removing as much foreign material as possible.

[0257] Following the removal of the second aqueous washing solution (W2), a rinsing sub-step g3) is carried out, as described above.

[0258] Step h) of the process involves drying the washed polypropylene recycling stream (G), thereby obtaining a dried polypropylene recycling stream (H). Step h) is an optional step of the process, as drying can be carried out during separation step i). However, it is important that the light fraction polypropylene recycling stream (I) obtained after step i) is in a dry state.

[0259] If present, the drying step h) can be carried out through thermal drying, mechanical drying or a combination thereof. Suitable forms of mechanical drying include centrifugal drying and a dewatering press (filter or screw-press), each of which allows for the separation of liquids from solids.

[0260] Step i) of the process involves separating the dried polypropylene recycling stream (H) or the washed polypropylene recycling stream (G) into a light fraction polypropylene recycling stream and a heavy fraction recycling stream, and selecting the light fraction polypropylene recycling stream (I).

[0261] The light fraction polypropylene recycling stream (I) predominantly contains flakes of flexible polypropylene articles, while the heavy fraction recycling stream predominantly contains flakes of rigid articles of polypropylene or other polymers. The sorting step d) will further reduce the content of rigid particles in the stream.

[0262] The separation step i) can be carried out by any known method in the art for such sorting operations, preferably by any dry-state density separation technique known in the art.Suitable techniques include pneumatic classifying, wind sifters, zig zag cascade and / or air separators.

[0263] As would be understood by the person skilled in the art, the separation into a light fraction and a heavy fraction recycling stream by such methods would not solely be influenced by the density of the flakes, but more critically by the aerodynamic properties of the flakes (typically influenced by surface area to weight ratio), e.g., flat labels are separated from the bulkier polymer flakes. The terms “light fraction" and “heavy fraction" are commonly used in the art and do not strictly refer to classification by density alone. The meaning of these terms in the present description matches these generally understood terms in the art.

[0264] Step j) of the process involves conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I).

[0265] The quality-control (2) step serves to the determine the efficiency of the proceeding process steps on the quality of the light fraction polypropylene recycling stream (I).

[0266] The quality of the light fraction polypropylene recycling stream (I) is based on the following parameters:

[0267] all of parameters j1 ) to j3):

[0268] j 1 ) the content of transparent flexible polypropylene flakes,

[0269] j2) the content of colored and non-transparent flexible polyethylene flakes, and j3) the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes; and / or

[0270] all of parameters j4) to j6):

[0271] j4) the content of transparent flexible polypropylene flakes,

[0272] j5) the content of polypropylene, and

[0273] j6) the content of polyethylene.

[0274] The light fraction polypropylene recycling stream (I) is allowed to proceed to step k) only if pre-determined conditions for these parameters are fulfilled.

[0275] Preferably, these pre-determined conditions are:

[0276] all of conditions j1) to j3):

[0277] j1) the content of transparent flexible polypropylene flakes is more than 80 wt.-%,j2) the content of colored and non-transparent flexible polyethylene flakes is below 2 wt.-%, and

[0278] j3) the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes is below 5 wt.-%; and / or

[0279] all of conditions j4) to j6):

[0280] j4) the content of transparent flexible polypropylene flakes is more than 80 % by number,

[0281] j5) the content of polypropylene is more than 92 wt.-%, and

[0282] j6) the content of polyethylene is below 6 wt.-%,

[0283] the contents in j1) to j3), j5) and j6) being relative to the total weight of the light fraction polypropylene recycling stream (I), and the content in j4) being relative to the total flake number of the light fraction polypropylene recycling stream (I).

[0284] Parameters j1) to j6) are evaluated based on the following features:

[0285] The wording “transparent flexible polypropylene flakes" of parameter j1) refers to flexible (article) flakes comprising at least 75 wt.-% of polypropylene, and wherein at least 90 % of the area of the flake (the area being one surface of the flexible flake) is transparent, i.e., have less than 20 % haze (determined according to ASTM D1003, and based on a cast film of 50 pm in thickness). Flexible flakes, wherein only up to 25 % of the area of the flake are transparent, are referred to as non-transparent flakes. Flexible flakes may contain ink on their surface that prevents transparency. Thus, flexible flakes, wherein between 25 and 90 % of the area of the flake are transparent, are referred to as partly colored flakes (these flakes typically have 10 to 75 % of the area of the flake covered by colored ink).

[0286] The wording “colored and non-transparent flexible polyethylene flakes" of parameter j2) refers to flexible (article) flakes comprising at least 75 wt.-% of polyethylene, wherein only up to 25 % of the area of the flake (the area being one surface of the flexible flake) is transparent, i.e., have less than 20 % haze (determined according to ASTM D1003, and based on a cast film of 50 pm in thickness). Flexible flakes, wherein only up to 25 % of the area of the flake are transparent, are referred to as non-transparent flakes. Flexible flakes may contain ink on their surface that prevents transparency. Thus, flexible flakes, wherein between 25 and 90 % of the area of the flake are transparent, are referred to as partly colored flakes. Further, at least 75 % of the area of the flake (the area being one surface of the flexible flake) are colored, i.e., typically has a colored ink on the surface.Color may be determined based on the RDB system, wherein pure white has each of R, D and B values of 255. Accordingly, a colored material generally has at least one of the R, D and B values of less than 250. Flexible flakes, wherein between 10 and 75 % of the area of the flake are colored, are referred to as partly colored flexible flakes. Flexible flakes, wherein only up to 10 % of the area of the article are colored, are referred to as non-colored articles.

[0287] The wording “materials other than flexible polypropylene flakes or flexible polyethylene flakes" of parameter j3) refers to any materials that are not flexible polypropylene flakes (i.e., flexible (article) flakes comprising at least 75 wt.-% of polypropylene) or flexible polyethylene flakes (i.e., flexible (article) flakes comprising at least 75 wt.-% of polyethylene). These can be flakes or other articles that are not flexible flakes, e.g., rigid flakes, fibers etc., and / or flexible flakes made of other materials.

[0288] The wording “transparent flexible polypropylene flakes" of parameter j4) is referred to the same articles as described for parameter j1) above. When using a flake analyzer, the content is given in % by number of the flakes.

[0289] Typically, parameters j5) and j6) are determined by spectroscopic methods, wherein the total content of polypropylene or polyethylene, respectively, in the sample is obtained. Preferably, the quality of the light fraction polypropylene recycling stream (I) in step j) is determined by sorting by hand following a visual inspection for parameters j1) to j3), on a sample from the light fraction polypropylene recycling stream (I).

[0290] Preferably, the quality of the light fraction polypropylene recycling stream (I) in step j) is determined by optical imaging via near-IR spectroscopic analysis, near-IR / VIS spectroscopic analysis, a camera system operating in the visible range of the EM-spectrum, optionally by the use of a flake analyzer; and / or by Fourier-transform infrared (FTIR) spectroscopic analysis for parameters j4) to j6) , on a sample from the light fraction polypropylene recycling stream (I).

[0291] More preferably, the content in j4) is determined, optionally by the use of a flake analyzer device, by optical imaging via near-IR spectroscopic analysis, near-IR / VIS spectroscopic analysis and / or a camera system operating in the visible range of the EM -spectrum; and the contents in j5) and j6) are determined, optionally by the use of a flake analyzer device, by near-IR spectroscopic analysis, near-IR / VIS spectroscopic analysis and / or are determined by Fourier-transform infrared (FTIR) spectroscopic analysis, on a sample from the light fraction polypropylene recycling stream (I). The use of a flake analyzer device is particularly preferred as it may combine two or more of the detections methods: near-IRspectroscopic analysis, near-IR / VIS spectroscopic analysis and / or a camera system operating in the visible range of the EM-spectrum.

[0292] Accordingly, the determination of parameters in the quality-control (2) step may be carried out with the use of an optical detector or without the use of an optical detector by sorting by hand following a visual inspection. Sorting by hand by a skilled person is very reliable and able to identify articles that may not be found by the optical detector. Sorting by hand following a visual inspection operates on the same principles as the use of camera systems in combination with either simple recognition algorithms or more complex Al- based systems, with the latter expected to predominate, as Al recognition improves yet further.

[0293] The light fraction polypropylene recycling stream (I) is allowed to proceed to step k) if the pre-determined conditions for the above parameters are fulfilled, thereby generating a quality-controlled (2) polypropylene recycling stream (J1).

[0294] Otherwise, if the pre-determined conditions are not fulfilled, the light fraction polypropylene recycling stream (I) is combined with a polypropylene recycling stream (Y) that fulfills the pre-determined conditions, thereby generating a quality-controlled (2) polypropylene recycling stream (J2).

[0295] Preferably, the light fraction polypropylene recycling stream (I) is combined with the polypropylene recycling stream (Y) in a ratio of the light fraction polypropylene recycling stream (I) to the polypropylene recycling stream (Y) in the range of from 0.05:1 to 5:1, preferably from 0.1:1 to 2:1, such as from 0.5:1 to 1:1. The ratio will typically depend from the purity of the light fraction polypropylene recycling stream (I) and the purity of the polypropylene recycling stream (Y), in particular, based on the pre-determined conditions j1) to j3) and / or j4) to j6) as specified above. Preferably, the light fraction polypropylene recycling stream (I) is combined with a polypropylene recycling stream (Y) in such a ratio that the generated quality-controlled (2) polypropylene recycling stream (J2) fulfills the conditions j1 ) to j3) and / or j4 to j6) , as defined above.

[0296] In this way, the quality of the light fraction polypropylene recycling stream (I) is improved. In some embodiments, the determination of the quality of the light fraction polypropylene recycling stream (I) in step j) may be further based on the content of at least one metal, preferably selected from titanium (Ti), calcium (Ca) and aluminum (Al), on a sample from the light fraction polypropylene recycling stream (I), preferably using X-ray fluorescence (XRF) spectroscopy.Step k) of the process involves melt-extruding, and preferably pelletizing, the quality- controlled (2) polypropylene recycling stream (J), preferably wherein additives (Ad) are added in the melt state, to form an extruded, and preferably pelletized, polypropylene recycling product (K). As the subsequent aeration step I) is optional, the extruded, and preferably pelletized, polypropylene recycling product (K) can be the (final) mixed-plastic polypropylene recycling blend.

[0297] The quality-controlled (2) polypropylene recycling stream (J) may be the quality-controlled (2) polypropylene recycling stream (J1) and / or the quality-controlled (2) polypropylene recycling stream (J2).

[0298] The extrusion of the quality-controlled (2) polypropylene recycling stream (J) in step k) is preferably carried out by a conventional compounding or blending apparatus or an extruder, e.g., a Banbury mixer, a 2-roll rubber mill, a Buss-co-kneader or a twin-screw extruder, such as a co-rotating twin-screw extruder. The extruded polypropylene recycling product (K) recovered from the extrusion apparatus is preferably in the form of pellets, i.e., it is a pelletized polypropylene recycling product (K).

[0299] It is preferred that the melt-extrusion of step k) preferably includes a melt-filtration step, wherein larger gels and other particles are reduced in size by filtration. This notably reduces the content of respective inclusions of larger sizes (such as >50 pm), and improves the quality of the resultant recyclate.

[0300] The melt-filtration step may include one or more filtration sub-steps, which may optionally be separated by a degassing and / or vacuumizing sub-steps. Generally, in the filtration sub-step(s), filters may be employed such as in the form of filter plates (preferably continuous laser filter plates). In case of more than one filtration sub-step, the average pore sizes of the filters may be same or different. Preferably, the average pore sizes of the filters decrease with the sequence of the filtration sub-steps. This enables efficient filtration with less contamination and blocking of the filters, as the particles are separated by the filters in the sequence of reduced sizes.

[0301] The first filter may comprise a perforated metal plate or drum, and the second filter may comprise a fiber mesh, for example, a metal fiber mesh. The second filter can also be a laser filter, but usually it is a filter with a filter mesh such as a band filter, a screen changer or a belt filter. The first filter may have a mesh size of 70 to 150 pm, preferably 75 to 130 pm, more preferably 80 to 110 pm. The second filter may have a mesh size of 40 to 130 pm, preferably 45 to 110 pm, more preferably 50 to 100 pm. The second filter may have a mesh size smaller than that of the first filter. Perforations in the first filter may be formed by laser (laser filter).A cascade of filters may be used, for example, a cascade of more than two filters is used, such as three, four or five filters. Where a cascade of two or more filters is used, the second or subsequent filter may have a mesh size that is smaller than the mesh size of the filter that immediately precedes it in the cascade.

[0302] The first filter may have perforations that are not uniform in cross-section. For example, the perforations may be frustoconical in cross section, such that each perforation has a minor and major diameter. The second filter may have a mesh size that is smaller than at least the major diameter of the first filter, preferably smaller than both the major and minor diameter of the first filter.

[0303] It is preferred that step k) comprises a first filtration sub-step k1), a vacuum degassing sub-step k2) and a second filtration sub-step k3). Preferably in sub-step k1), a filter 1, preferably a continuous laser filter 1 , with larger average pore size is used than is present in the filter 2 in sub-step k3). Preferably, the average pore size of the filter 1 is larger by a factor in the range of from 1.5 to 2.5 than the average pore size of the filter 2.

[0304] Preferably additives (Ad) are added during step k), preferably in the melt state. These additives may be selected from additives known in the art, as described herein above. Step I) of the process involves aerating, preferably at an air temperature in the range of from 100 to 150 °C, the extruded, and preferably pelletized, polypropylene recycling product (K) to remove volatile organic compounds, thereby generating an aerated extruded, preferably pelletized, polypropylene recycling product (L), and thus providing the mixed-plastic polypropylene recycling blend. Step I) is an optional step of the process. The aeration step I) may be generally carried out using air, inert gases and / or steam. The aeration step I) ensures that the content of volatile organic compounds is minimized in the extruded, and preferably pelletized, polypropylene recycling product (K), avoiding any unpleasant odors that are typically associated with similar recycled polymer blends. These volatile organic compounds typically result from contamination of the polymer during the first consumer use, for example through contact with foods, skin care products or other toiletries, or simply through decomposition of the polyolefin and / or the contaminants into volatile oligomeric chains during processing steps.

[0305] Experimental Part

[0306] The following Examples are included to demonstrate certain aspects and embodiments of the invention as described in the claims. It should be appreciated by those skilled in theart, however, that the following description is illustrative only and should not be taken in any way as a restriction of the invention.

[0307] a) Melt Flow rate

[0308] Melt flow rates were measured with a load of 2.16 kg (MFR2) at 230 °C as indicated. The melt flow rate is the quantity of polymer in grams which the test apparatus standardized to ISO 1133 extrudes within 10 minutes at a temperature of 230 °C under a load of 2.16 kg.

[0309] b) Density

[0310] The density of the materials is measured according to ISO 1183-187. Sample preparation is done by compression moulding in accordance with ISO 1872-2:2007.

[0311] The density of the films has been measured according to DIN EN ISO 845.

[0312] c) Determination of components of a polymer composition

[0313] Fourier-transform infrared (FTIR) spectroscopy

[0314] Sample preparation:

[0315] All calibration samples and samples to be analyzed were prepared in similar way, on molten pressed plates.

[0316] About 2 to 3 g of compounds to be analyzed were melted at 190°C. Subsequently, for 20 seconds, 60 to 80 bar pressure was applied in a hydraulic heating press. Next, the samples were cooled to room temperature in 40 seconds in a cold press under the same pressure, in order to control the morphology of the compound. The thickness of the plates was controlled by metallic calibrated frame plates 2.5 cm by 2.5 cm, 100 to 200 pm thick (depending MFR from the sample); two plates were produced in parallel at the same time and in the same conditions. The thickness of each plate was measured before any FTIR measurements were performed; all plates were between 100 to 200 pm thick.

[0317] To control the plate surface and to avoid any interference during the measurement, all plates were pressed between two double-sided silicone release papers.

[0318] In case of powder samples or heterogeneous compounds, the pressing process was repeated three times to increase homogeneity by pressing and cutting the sample in the same conditions as described before.

[0319] Spectrometer:Standard transmission FTIR spectroscope such as Bruker Vertex 70 FTIR spectrometer was used with the following set-up:

[0320] o a spectral range of 4000-400 cm’1,

[0321] o an aperture of 6 mm,

[0322] o a spectral resolution of 2 erm1,

[0323] o with 16 background scans, 16 spectrum scans,

[0324] o an interferogram zero filling factor of 32

[0325] o Norton Beer strong anodization.

[0326] Spectra were recorded and analyzed in Bruker Opus software.

[0327] Calibration samples:

[0328] As FTIR is a secondary method, several calibration standards were compounded to cover the targeted analysis range, typically from:

[0329] o 0.2 wt% to 2.5 wt% for PA

[0330] o 0.1 wt% to 5 wt% for PS

[0331] o 0.2 wt% to 2.5 wt% for PET

[0332] o 0.1 wt% to 4 wt% for PVC

[0333] The following commercial materials were used for the compounds: Borealis HC600TF as iPP, Borealis FB3450 as HDPE and for the targeted polymers such RAMAPET N1S (Indorama Polymer) for PET, Ultramid® B36LN (BASF) for Polyamide 6, Styrolution PS 486N (Ineos) for High Impact Polystyrene (HIPS), and for PVC Inovyn PVC 263B (under powder form).

[0334] All compounds were made at small scale in a Haake kneader at a temperature below 265°C and less than 10 minutes to avoid degradation.

[0335] Additional antioxidant such as Irgafos 168 (3000 ppm) was added to minimize the degradation.

[0336] Calibration:

[0337] The FTIR calibration principle was the same for all the components: the intensity of a specific FTIR band divided by the plate thickness is correlated to the amount of component determined by1H or13C solution state NMR on the same plate.Each specific FTIR absorption band was chosen due to its intensity increase with the amount of the component concentration and due to its isolation from the rest of the peaks, whatever the composition of the calibration standard and real samples.

[0338] This methodology is described in the publication from Signoret and al. “Alterations of plastic spectra in MIR and the potential impacts on identification towards recycling”, Resources, conservation and Recycling journal, 2020, volume 161, article 104980.

[0339] The wavelength for each calibration band was:

[0340] o 3300 cm-1for PA,

[0341] o 1601 cm-1for PS,

[0342] o 1410 cm-1for PET,

[0343] o 615 cm-1for PVC,

[0344] o 1167 erm1for iPP.

[0345] For each polymer component i, a linear calibration (based on linearity of Beer-Lambert law) was constructed. A typical linear correlation used for such calibrations is given below:

[0346]

[0347] where

[0348] xi is the fraction amount of the polymer component i (in wt%),

[0349] Ei is the absorbance intensity of the specific band related to the polymer component i (in a.u. absorbance unit, values see above),

[0350] d is the thickness of the sample plate,

[0351] Ai and Bi are two coefficients of correlation determined for each calibration curve.

[0352] No specific isolated band can be found for C2-rich fraction and as a consequence the C2-rich fraction is estimated indirectly,

[0353] C2 rich 100

[0354]

[0355] The Chalk and Talc contents are estimated “semi-quantitatively”. Hence, this renders the C2 rich content “semi-quantitative”.

[0356] For each calibration standard, wherever available, the amount of each component was determined by either1H or13C solution state NMR, as primary method (except for PA). The NMR measurements were performed on the exact same FTIR plates used for the construction of the FTIR calibration curves.Ash content

[0357] Thermogravimetric Analysis (TGA) experiments were performed with a Perkin Elmer TGA 8000. Approximately 15-25 mg of materials were placed in a platinum pan. The temperature was equilibrated at 50°C for 10 minutes, and afterwards raised to 950°C under nitrogen at 20°C / min. The weight loss between ca. 550°C and 700°C (WC02) was assigned to CO2 evolving from CaCCh, and therefore the chalk content was evaluated as: Chalk content = 100 / 44 x WCO2

[0358] Afterwards the temperature was lowered to 300°C at 20°C / min, gas switched to oxygen, and the temperature was raised again to 900°C. The weight loss in this step was assigned to carbon black (Web). Knowing the content of carbon black and chalk, the content of inorganic residues excluding chalk and carbon black can be calculated from the ash residue as:

[0359] Inorganic residues content = (Ash residue) - 56 / 44 x WCO2 - Web

[0360] Where Ash residue is the weight% measured at 850°C in the first step conducted under nitrogen.

[0361] Content of Inorganic Elements

[0362] The content of inorganic elements was determined by X-ray fluorescence (XRF). The instrument used for the XRF measurements was a wavelength dispersive Zetium (2,4kW) from Malvern Panalytical. The instrument was calibrated with Adpol, RoHs, Toxel standards from Malvern Panalytical and from a custom set of calibration standards (referred to in the following as “Custom”) also from Malvern Panalytical according to the following table:

[0363]

[0364] The analyses are done under vacuum on a plaque with a diameter of 40mm and a thickness of 2mm.

[0365] The method is generally used to determine the quantitative content of Na, Mg, Al, Si, P, S, Ca, Ti, Zn, Cu, Br, Cl, K, Sr, Fe in polyolefin matrix within defined ranges of these standards.

[0366] The content of each precise element was evaluated with the following standards:

[0367]

[0368] Elements which are not covered by standards, or in case the content is outside of the calibrated standard range, are then analyzed with a semi-quantitative mode (software Omnian from Malvern Panalytical). For elements not covered by the calibration standards, no value is reported if the corresponding peak is not visible and therefore cannot be analyzed with the software Omnian.

[0369] The CH content needed to run the semiquantitative evaluation with Omnian was estimated by the software itself.

[0370] 13C NMR spectroscopy-based determination of C2 content for the calibration standards Quantitative13C{1H} NMR spectra were recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C, respectively. All spectra were recorded using a13C optimised 10 mm extended temperature probehead at 125 °C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1 , 2-tetrachloroethane-d2 (TCE-d2) along with chromium (III) acetylacetonate (Cr(acac)s) resulting in a 65 mM solution of relaxation agent in solvent (Singh, G., Kothari, A, Gupta, V., Polymer Testing 285 (2009), 475). To ensure a homogenous solution, after initial sample preparation in a heat block, the NMRtube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R, Qiu, X., Redwine, D Cong, R, Taha, A, Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225, Busico, V., Carbonniere, P Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) transients were acquired per spectra. Quantitative13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed (Cheng, H. N., Macromolecules 17 (1984), 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer:

[0371] fE=(E / (P+E))

[0372] The comonomer fraction was quantified using the method of Wang et. al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157) through integration of multiple signals across the whole spectral region in the13C{1H} spectra. This method was chosen for its robust nature and ability to account for the presence of regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents. For systems with very low ethylene content where only isolated ethylene in PPEPP sequences were observed the method of Wang et. al. was modified reducing the influence of integration of sites that are no longer present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reduction of the number of sites used to determine the absolute ethylene content to

[0373] E = 0.5(Spp + SBy + Sp5 + 0.5( Sap + Say))

[0374] Through the use of this set of sites the corresponding integral equation becomes

[0375] E = 0.5(IH +IG + 0.5(IC + ID ))

[0376] using the same notation used in the article of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157). Equations used for absolute propylene content werenot modified. The mole percent comonomer incorporation was calculated from the mole fraction:

[0377] E [mol%] = 100 * fE.

[0378] The weight percent comonomer incorporation was calculated from the mole fraction: E [wt.-%] = 100 * (fE * 28.06) / ((fE * 28.06) + ((1 -fE) * 42.08))

[0379] d) Quantification of microstructure by NMR spectroscopy

[0380] Isotacticity

[0381] Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the isotacticity of the polymers.

[0382] Quantitative13C{1H} NMR spectra recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C respectively. All spectra were recorded using a13C optimised 10 mm selective excitation probehead at 125°C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in approximately 3 ml of 1 ,2-tetrachloroethane-d2 (TCE-d2) along with approximately 3 mg BHT (2,6-di-tert-butyl-4-methylphenol CAS 128-37-0). To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution needed for tacticity distribution quantification {busicoOl, busico97}. Standard single-pulse excitation was employed utilising the NOE, 3 s recycle delay and bi-level WALTZ16 decoupling scheme {zhou07,busico07}. A total of 8192 (8k) transients were acquired per spectra.

[0383] 13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were internally referenced to the methyl signal of the isotactic pentad mmmm at 21.85 ppm.

[0384] The tacticity distribution was quantified through integration of the methyl region between 23.6 and 19.7 ppm correcting for any sites not related to the stereo sequences of interest {busicoOl, busico97}.

[0385] Characteristic signals corresponding to the presence of regio defects {resconiOO} were not observed.The pentad tacticity distribution was determined through direct separate integration of each methyl signal from a given steric pentad followed by normalisation to the sum of methyl signals from all steric pentads. The relative content of a specific steric pentad was reported as the mole fraction or percentage of a given steric pentad xxxx with respect to all steric pentads:

[0386] [xxxx] = xxxx / (mmmm + mmmr + rmmr + mmrr + xmrx + mrmr + rrrr + mrrr + mrrm) where xmrx represents the combined integral of both mmrm and rmrr as signal from these steric pentads are not commonly resolved. The pentad isotacticity was thus given by: [mmmm] = mmmm / (mmmm + mmmr + rmmr + mmrr + xmrx + mrmr + rrrr + mrrr + mrrm) busicoOl Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443

[0387] busico97 Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromoleucles 30 (1997) 6251

[0388] zhou07 Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225

[0389] busico07 Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128

[0390] resconiOO Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253

[0391] Comonomer content in C3C2C4 terpolymers

[0392] Quantitative13C{1H} NMR spectra are recorded in the molten-state using a Bruker Advance III 500 NMR spectrometer operating at 500.13 and 125.76 MHz for1H and13C respectively. All spectra were recorded using a13C optimised 7 mm magic-angle spinning (MAS) probehead at 180°C using nitrogen gas for all pneumatics. Approximately 200 mg of material was packed into a 7 mm outer diameter zirconia MAS rotor and spun at 4.5 kHz. This setup was chosen primarily for the high sensitivity needed for rapid identification and accurate quantification {klimke06, parkinson07, castignolles09}. Standard single¬ pulse excitation was employed utilising the NOE at short recycle delays {pollard04, klimke06} and the RS-HEPT decoupling scheme{fillip05,griffin07}. A total of 1024 (1k) transients were acquired per spectra.Quantitative13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm.

[0393] Characteristic signals corresponding to regio defects were not observed {resconiOO}. The amount of propene was quantified based on the main Saa methylene sites at 44.1 ppm: PtOtal = Isaa

[0394] Characteristic signals corresponding to the incorporation of 1 -butene were observed and the comonomer content quantified in the following way. The amount of isolated 1 -butene incorporated in PPBPP sequences was quantified using the integral of the aB2 sites at 44.1 ppm accounting for the number of reporting sites per comonomer:

[0395] B = laB2 / 2

[0396] The amount consecutively incorporated 1 -butene in PPBBPP sequences was quantified using the integral of the aaB2 site at 40.5 ppm accounting for the number of reporting sites per comonomer:

[0397] BB — 2 * laaB2

[0398] The total 1 -butene content was calculated based on the sum of isolated and consecutively incorporated 1 -butene:

[0399] Btotal = B + BB

[0400] The total mole fraction of 1 -butene in the polymer was then calculated as:

[0401] fB = ( Btotal / ( Etotal + Ptotal + Btotal ))

[0402] Characteristic signals corresponding to the incorporation of ethylene were observed and the comonomer content quantified in the following way. The amount isolated ethylene incorporated in PPEPP sequences was quantified using the integral of the Say sites at 37.9 ppm accounting for the number of reporting sites per comonomer:

[0403] E = Isay / 2

[0404] With no sites indicative of consecutive incorporation observed the total ethylene comonomer content was calculated solely on this quantity:Etotal = E

[0405] The total mole fraction of ethylene in the polymer was then calculated as:

[0406] fE = ( Etotal / ( Etotal + Ptotal + Btotal )

[0407] The mole percent comonomer incorporation was calculated from the mole fractions: B [mol-%] = 100 * fB

[0408] E [mol-%] = 100 * fE

[0409] The weight percent comonomer incorporation was calculated from the mole fractions: B [wt.-%] = 100 * ( fB * 56.11 ) / ( (fE * 28.05) + (fB * 56.11) + ((1-(fE+fB)) * 42.08) ) E [wt.-%] = 100 * ( fE * 28.05 ) / ( (fE * 28.05) + (fB * 56.11) + ((1-(fE+fB)) * 42.08) ) Literature:

[0410] klimke06 Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382.

[0411] parkinson07 Parkinson, M., Klimke, K., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys.

[0412] 2007; 208:2128.

[0413] pollard04 Pollard, M., Klimke, K., Graf, R., Spiess, H.W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37:813.

[0414] filip05 Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239.

[0415] griffin07 Griffin, J.M., Tripon, C., Samoson, A., Filip, C., and Brown, S.P., Mag. Res. in Chem. 200745, S1, S198.

[0416] castignolles09 Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373.

[0417] busicoOl Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443.

[0418] busico97 Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromoleucles 30 (1997) 6251.

[0419] zhou07 Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225.busico07 Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128.

[0420] resconiOO Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253.

[0421] e) Crystex analysis, crystalline fraction (OF) and soluble fraction (SF) The crystalline (CF) and soluble fractions (SF) of the PCR polypropylene composition as well as the ethylene content and intrinsic viscosities of the respective fractions were analyzed by use of the CRYSTEX instrument, Polymer Char (Valencia, Spain) in line with ISO16152-2022 - Method 2. Details of the technique and the method can be found in literature (Ljiljana Jeremie, Andreas Albrecht, Martina Sandholzer & Markus Gahleitner (2020) Rapid characterization of high-impact ethylene-propylene copolymer composition by crystallization extraction separation: comparability to standard separation methods, International Journal of Polymer Analysis and Characterization, 25:8, 581-596).

[0422] The crystalline and amorphous fractions are separated through temperature cycles of dissolution at 160 °C, crystallization at 40 °C and re-dissolution in 1,2,4-trichlorobenzene at 160 °C. Quantification of SF and CF and determination of ethylene content (C2) are achieved by means of an integrated infrared detector (IR4) and for the determination of the intrinsic viscosity (IV) an online 2-capi llary viscometer is used.

[0423] The IR4 detector is a multiple wavelength detector measuring IR absorbance at two different bands (CH3stretching vibration (centered at app. 2960 cm-1) and the CH stretching vibration (2700-3000 cm-1) that are serving for the determination of the concentration and the ethylene content in ethylene-propylene copolymers. The IR4 detector is calibrated with series of 8 EP copolymers with known ethylene content in the range of 2 wt.-% to 69 wt.-% (determined by13C-NMR) and each at various concentrations, in the range of 2 and 13 mg / ml. To encounter for both features, concentration and ethylene content at the same time for various polymer concentrations expected during Crystex analyses the following calibration equations were applied:

[0424] Cone = a + b*Abs(CH) + c*(Abs(CH))2+ d*Abs(CH3) + e*(Abs(CH3)2+ f*Abs(CH)*Abs(CH3) (equation 1)

[0425] CH3 / 1000C = a + b*Abs(CH) + c* Abs(CH3) + d * (Abs(CH3) / Abs(CH)) + e*(Abs(CH3) / Abs(CH))2(equation 2)

[0426] The constants a to e for equation 1 and a to f for equation 2 were determined by using least square regression analysis.The CH3 / OOC (total carbon content) is converted to the ethylene content in wt.-% using following relationship:

[0427] wt.-% (ethylene in EP copolymers) = 100 - CH3 / OOTC * 0.3,

[0428] wherein 1000TC means 1000 total carbon atoms.

[0429] Intrinsic viscosity (IV) of the PCR polypropylene composition and its soluble and crystalline fractions are determined by use of an online 2-capillary viscometer and are correlated to corresponding IV’s determined by standard method in decalin according to ISO 1628-3. Calibration is achieved with various EP / PP copolymers with IV = 2-4 dl / g. The determined calibration curve is linear:

[0430] IV (dl / g) = a* Vsp / c

[0431] wherein IV is the intrinsic viscosity, a is the slope of the calibration curve, c is the polymer concentration in solution, and Vsp is the specific viscosity.

[0432] The samples to be analyzed are weighed out in concentrations of 10 mg / ml to 20 mg / ml. To avoid injecting possible gels and / or polymers which do not dissolve in TCB at 160 °C, like PET and PA, the weighed out sample was packed into a stainless steel mesh MW 0.077 / D 0.05 mm.

[0433] After automated filling of the vial with 1,2,4-TCB containing 250 mg / l 2,6-tert-butyl-4- methylphenol (BHT) as antioxidant, the sample is dissolved at 160 °C until complete dissolution is achieved, usually for 60 min, with constant stirring of 400 rpm. To avoid sample degradation, the polymer solution is blanketed with the N2 atmosphere during dissolution.

[0434] A defined volume of the sample solution is injected into the column filled with inert support where the crystallization of the sample and separation of the soluble fraction from the crystalline part is taking place. This process is repeated two times. During the first injection the whole sample is measured at high temperature, determining the IV [dl / g] and the C2 [wt.-%] of the PP composition. During the second injection the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) with the crystallization cycle are measured (wt.-% SF, wt.-% CF, wt.-% C2, wt.-% C2(SF), wt.-% C2(CF), IV(SF), IV(CF)), where the wt.-% CF is calculated in the following way:

[0435] wt.-% CF = 100 -wt.-% SF9 Determination of high and low density inclusions in a polymer composition by X-ray Computed Tomography (X-ray CT)

[0436] X-ray Computed Tomography (CT) was performed using a Thermo Fisher Scientific Heliscan MK2 (Thermo Fisher Scientific) device. Pellets were scanned as delivered and placed in a cylindrical sample holder. The Voxel size was set to 4 pm. The X-ray tube was operated with LaB6 filament, voltage was set to 60 kV, focal spot size was set to medium and a pre-filter made of steel with 0.1 mm thickness was used. The specimens were scanned with Space Filling trajectory. For the reconstruction, the values for shift and scale, that are used for converting 32 bit to final 16 bit data, was fixed for all scans to be able to compare multiple data.

[0437] Together with the specimens, discs with 5 mm in diameter and 500 pm in thickness, made of different polymers, were scanned at once. At least a disc made of one PP grade and one PET grade have to be scanned.

[0438] The software Avizo for industrial inspection (Thermo Fisher Scientific) was used for data analysis. From the PP and PET discs, the grey values were determined acting as guide for thresholding. Specimen data was segmented into Polymer and air for the determination of total volume with a threshold which is 72 % lower than that of PP.

[0439] Specimen data was segmented with a grey value threshold, which is 11 % higher than that of PET leading to the fraction of high density particulate contaminants. Taking the density of PP with 0.905 g / cm3and that of PET with 1.38 g / cm3into account, this threshold corresponds to a density of 1.53 g / cm3.

[0440] A second analysis was performed with a lower threshold leading to the fraction of low density particulate contaminants. For this threshold the peak grey value of the pellets was determined. A threshold which was 26 % higher than that of the polymer peak was applied. This usually leads to a density of at least 1.1 g / cm3(such as of at least 1.14 g / cm3). All inclusions with a grey value higher than that of the first analysis, the high density particulate contaminants, were subtracted from this segmentation.

[0441] Each particle was segmented into an individual object using a Connected Component filter. The minimum object size was set to 5 Voxels. For each object, the features average grey value, position, volume, length, width and thickness were determined.

[0442] g) Dynamic Shear Measurements (Eta(2.7kPa) and Eta^oorad / s))

[0443] The characterization of polymer melts by dynamic shear measurements complies with ISO standards 6721-1 and 6721-10. The measurements were performed on an AntonPaar MCR501 stress controlled rotational rheometer, equipped with a 25 mm parallel plate geometry. Measurements were undertaken on compression-molded plates, using nitrogen atmosphere and setting a strain within the linear viscoelastic regime. The oscillatory shear tests were done at 200°C applying a frequency range between 628 and 0.01 rad / s, with data evaluation of 5 datapoints per decade and a logarithmic ramped strain of 2-7% that is used. The plate-plate geometry has a diameter of 25 mm and a gap size of 1.3 mm is used. The trimming is carried out at 1.4 mm.

[0444] In a dynamic shear experiment the probe is subjected to a homogeneous deformation at a sinusoidal varying shear strain or shear stress (strain and stress controlled mode, respectively). On a controlled strain experiment, the probe is subjected to a sinusoidal strain that can be expressed by

[0445] y(t) = To sin(tot) (1)

[0446] If the applied strain is within the linear viscoelastic regime, the resulting sinusoidal stress response can be given by

[0447] a(t) = a0sin (tot + 6) (2)

[0448] where

[0449] a0and y0are the stress and strain amplitudes, respectively

[0450] to frequency is the angular

[0451] 6 is the phase shift (loss angle between applied strain and stress response)

[0452] t is the time

[0453] Dynamic test results are typically expressed by means of several different rheological functions, namely the shear storage modulus G’, the shear loss modulus G”, the complex shear modulus G*, the complex shear viscosity r , the dynamic shear viscosity rf , the out- of-phase component of the complex shear viscosity q” and the loss tangent tan 5 which can be expressed as follows:

[0454] G' = ^cos6 [Pa] (3)

[0455] G" = — sin5 [Pa] (4)

[0456] Yo

[0457] G* = G' + iG" [Pa] (5)

[0458] r|* = rf — iT]" [Pa.s] (6)

[0459]

[0460] ETA(x kPa) is determined according with equation 9.

[0461] ETA(x kPa) = Eta* for (G* = x kPa [Pa.s] (9)

[0462] For example, the ETA(2.7 kPa) is the defined by the value of the complex viscosity, determined for a value of complex modulus equal to 2.7 kPa.

[0463] Eta (x rad / s) is determined according with equation 10.

[0464] ETA(x rad / s = Eta* for (o = x rad / s [Pa.s] (10)

[0465] For example, the ETA(300 rad / s) is defined by the value of the complex viscosity, determined at a frequency sweep of 300 rad / s.

[0466] Equally, the ETA(0.05 rad / s) is defined by the value of the complex viscosity, determined at a frequency sweep of 0.05 rad / s. g) Shear Thinning Factor (STF)

[0467] cyp >_Eta*for(^=0-05 rad / s)

[0468] Eta* for (co = 3OO rad / s)

[0469]

[0470] The values are determined by means of a single point interpolation procedure, as defined by Rheoplus software. In situations for which a given G* value is not experimentally reached, the value is determined by means of an extrapolation, using the same procedure as before. In both cases (interpolation or extrapolation), the option from Rheoplus Interpolate y-values to x-values from parameter” and the “logarithmic interpolation type” were applied.

[0471] References:

[0472] [1] Rheological characterization of polyethylene fractions” Heino, E.L., Lehtinen, A., Tanner J., Seppala, J., Neste Oy, Porvoo, Finland, Theor. Appl. Rheol., Proc. Int. Congr. Rheol, 11th (1992), 1 , 360-362

[0473] [2] The influence of molecular structure on some rheological properties of polyethylene”, Heino, E.L., Borealis Polymers Oy, Porvoo, Finland, Annual Transactions of the Nordic Rheology Society, 1995.).

[0474] [3] Definition of terms relating to the non-ultimate mechanical properties of polymers, Pure & Appl. Chem., Vol. 70, No. 3, pp. 701-754, 1998.h) Flexural Modulus

[0475] The flexural modulus was determined according to ISO 178 method A (3-point bending test) on 80 mm x 10 mm x 4 mm specimens (type B) on the BOPP films produced as described in the example section below. Following the standard, a test speed of 2 mm / min and a span length of 16 times the thickness was used. The testing temperature was 23 ±2° C. Injection moulding was carried out according to ISO 19069-2.

[0476] i) Film gloss (45°)

[0477] The film gloss was determined according to ASTM D2457 at 45 degree on the BOPP films produced as described in the example section below .

[0478] j) Transmitance, Haze, Clarity

[0479] Transmittance, haze, and clarity were determined according to ASTM D1003 on the BOPP films produced as described in the example section below.

[0480] k) Glass Transition temperature (Tg)

[0481] The glass transition temperature Tg was determined by dynamic mechanical analysis according to ISO 6721-7. The measurements were done in torsion mode on compression moulded samples (40x10x1 mm3) between -100 °C and +150 °C with a heating rate of 2 °C / min and a frequency of 1 Hz.

[0482] l) Melting temperature (Tm) and Crystallization temperature (Tc)

[0483] The melting temperature (Tm) and crystallization temperature (Tc) were determined according to ISO 11357. Experiments were performed with a TA Instruments Q200, calibrated with Indium, Zinc, Tin and according to ISO 11357-3. Roughly 5 mg of material were placed in a pan and tested at 10°C / min throughout the experiments, under 50 mL / min nitrogen flow, with lower and higher temperatures of -30°C and 180°C respectively. Only the second heating run was considered for the analysis. The melting temperature Tm is defined as the temperature of the main peak of the thermogram, while the melting enthalpy (AHm) is calculated by integrating between 10°C and the end of the thermogram, typically Tm+15°C. The running integral in this range is also calculated. m) Molecular weight distribution (Mw / Mn) by DSC

[0484] Molecular weight averages (Mz, Mw and Mn), Molecular weight distribution (MWD)and its broadness, described by polydispersity index, PDI = Mw / Mn (wherein Mn is the number average molecular weight and Mw is the weight average molecular weight) were determined by Gel Permeation Chromatography (GPC) according to ISO 16014-1:2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D 6474-12 using the following formulas:

[0485]

[0486] For a constant elution volume interval AVi, where Ai, and Mi are the chromatographic peak slice area and polyolefin molecular weight (MW), respectively associated with the elution volume, Vi, where N is equal to the number of data points obtained from the chromatogram between the integration limits.

[0487] A high temperature GPC instrument, equipped with a multiple band infrared detector model IR5 (PolymerChar, Valencia, Spain), equipped with 3 x Agilent-PLgel Olexis and 1x Agilent-PLgel Olexis Guard columns was used. As the solvent and mobile phase 1 ,2,4-trichlorobenzene (TCB) stabilized with 250 mg / L 2,6-Di tert butyl-4- methyl-phenol) was used. The chromatographic system was operated at 160 °C at a constant flow rate of 1 mL / min. 200 pL of sample solution was injected per analysis. Data collection was performed by using PolymerChar GPC-one software. The column set was calibrated using universal calibration (according to ISO 16014- 2:2003) with 19 narrow MWD polystyrene (PS) standards in the range of 0,5 kg / mol to 11 500 kg / mol. The PS standards were dissolved at room temperature over several hours. The conversion of the polystyrene peak molecular weight to polyolefin molecular weights is accomplished by using the Mark Houwink equation and the following Mark Houwink constants:

[0488] KPS = 19 x 10-3mL / g, aPS= 0.655KPE = 39 x 10-3mL / g, aPE= 0.725

[0489] A third order polynomial fit was used to fit the calibration data.

[0490] All samples were prepared in the concentration range of 0.5 to1 mg / ml and dissolved at 160°C for 3 hours under continuous gentle shaking.

[0491] n) Xylene soluble content (XCS)

[0492] The content of xylene cold solubles (XCS) was determined at 25°C according ISO 16152; first edition; 2005-07-01.

[0493] EXAMPLES

[0494] Biaxially oriented polypropylene films were prepared from the following recyclate polypropylene compositions.

[0495] RE1 is a propylene homopolymer that is commercially available from Borealis AG (AT). RE1 has the following properties:

[0496] MFR2(230 °C) of 3.2 g / 10 min,

[0497] Pentad isotacticity [mmmm] of 92.4% and free from 2,1 -regiodefects,

[0498] Tm of 162 °C,

[0499] XCS of 3.0 wt.-%, and

[0500] Mw / Mn of 6.78.

[0501] Mixed-plastic polypropylene recycling blends (PP1 and PP2) were prepared by the above¬ outlined recycling process, wherein both quality control steps (1) and (2) were used for PP2, and only quality control (2) step was used for PP1.

[0502] PP1 is a PP transparent fraction from a German post-consumer plastic trash fulfilling the specification DSD323-2 that was used as precursor mixed-plastic recycling stream. The mixed flexible packaging feedstock is processed according to the process described in the invention to obtain the transparent fraction

[0503] PP2 is a PP transparent fraction from a pre-sorted PP flexible packaging feedstock, from post-consumer plastic trash that was enriched in post-consumer flexible polypropylene articles, supplied by a German company, and it is processed according to the recycling process as disclosed herein to obtain the transparent fraction.

[0504] The content of flexible polymer articles in PP2 was 81.4 wt.-% (with a PP:PE ratio of 23.8:1) and in PP1 was 71.1 wt.-% (with a PP:PE ratio of 0.3:1).PP3 (comparative) is a PP coloured fraction from a German post-consumer plastic trash fulfilling the specification DSD323-2 that was used as precursor mixed-plastic recycling stream. The mixed flexible packaging feedstock is processed according to the same recycling process as disclosed herein to obtain the transparent fraction, without quality control steps.

[0505] The process was conducted by the sequence of steps: a) providing the precursor mixed- plastic recycling stream (A) described above; b) separating via sieving; c) removing metal particles; d) sorting according to polymer type, transparency, color and reflectance via optical sorters (for PP1 and PP2 the transparent sorted fractions and for PP3 the colored sorted fraction were further processed); e) quality control step (1) for PP2 (based on parameters e1) to e6), as indicated in Table 2); f) size-reducing via wet grinding; g) washing by cold alkaline wash, hot alkaline wash and rinsing (sub-steps g1a) to g3)); h) mechanical drying followed by thermal drying; i) separating via air sifter; j) quality-control step (2) (based on parameters j1) to j6), as indicated in Table 2); k) extrusion under the conditions identified in Table 1 in the presence of 0.3 wt.-% of antioxidants and obtained as pellets; and aerating at 120 °C for 22 h.

[0506] Table 1: Extrusion conditions.

[0507]

[0508] Quality control steps

[0509] The results of the quality control steps for the Inventive Examples PP1 and PP2 are summarized in Table 2 below:Table 2: Results of the quality control steps.

[0510] Composition (wt.-%) PP1 PP2

[0511] Quality control step (1) via hand sorting

[0512] PP flexibles 82 Transparent PP flexibles 40 Partly-colored PP flexibles 30 Colored PP flexibles 7 Metallized PP flexibles 5 pP flovihloeNo quality control (1) „ Organic materials (PS,

[0513]

[0514] PVC, PET, etc.) Paper

[0515] MMML flexibles* 4 Rest 3

[0516] Quality control step (2) via hand sorting

[0517] PP flexibles 94 96 Transparent PP flexibles 84 87 Colored and partly- g

[0518]

[0519] colored PP flexibles

[0520] White PP flexibles 2 2 Fibers 3 1.5 PE flexibles

[0521] (colored / non- 1.3 1.5 transparent)

[0522] Rigids (PO) and other

[0523] polymers (PS, PVC, 1.4 1 PET, PU, foams etc.)

[0524] PaperMetallized PP flexibles

[0525] Rest 0.3

[0526] Quality control step (2)

[0527] PP (IR) 94 94.2 Transparent PPoo>

[0528] „ .. | * ,,, . . , n.m. 88.8

[0529] flexibles (flake analyzer)

[0530] Organic materials (IR)

[0531] (PS, PET, barrier layers, 0.1 0.2

[0532] etc.)

[0533] PE (IR) 4.7 5

[0534] Ti (XRF) 1130 1079

[0535] Ca (XRF) 948 536

[0536] AI (XRF) 124 110

[0537] * The values for transparent PP flexibles in the quality control step (2) are indicated as % by number (measured via flake analyzer as described below); all other values are indicated as wt.-%.

[0538] ■MMML = multi-material multi-layer articles

[0539] n.m. = not measured

[0540] Measurement of transparent flexible polypropylene flakes via flake analyzer

[0541] This measurement was done to validate the results (number%) obtained by the flake analyzer.

[0542] The number- % of transparent flexible PP flakes in the blend of PP1 was determined with a flake analyzer under the following conditions:

[0543] Flake Analyzer 2.0 by RTT; the instrument processes samples of up to 8 kg of flakes of 2-30 mm at a throughput of about 250 g / min. The instrument is equipped with a laser, a color camera and NIR camera.

[0544] An analytical balance by Sartorius AG Germany was used, with a load max. of 620 g and min. of 0.02 g; with d, representing the standard division size, of 0.001 in the range of 0- 120 g; and e, the stated accuracy or certified reliability, is 0.01g.

[0545] A sample of ca. 35 g flakes was sorted by hand separating the transparent flexible PP flakes from the rest. Transparent flexible PP flakes were collected and the fractions wereindividually analyzed by the flake analyzer, resulting in a total number of flakes and a number of transparent flexible PP flakes.

[0546] Table 3: Results of the analysis by flake analyzer.

[0547] Flake Analyzer

[0548] Composition

[0549] n (number) % by number

[0550] PP transparent 5516 88.80

[0551] Total 6212 100.00

[0552] The results from the flake analyzer were verified by comparing results via hand sorting (the items of both categories - transparent flexible PP flakes and the rest - were counted per hand). The difference between flake analyzer and hand sorting was around 1 % on the percentage of transparent flakes (88.8 % via flake analyzer versus 90,08 % via hand sorting), indicating a high reliability of the flake analyzer.

[0553] Characteristics of the polymer blends

[0554] The prepared polymer blends were analyzed for their contents and properties. The obtained results are depicted in Tables 4 to 7 below.

[0555] Table 4: Properties of the polymer blend.

[0556]

[0557] PP2

[0558] PP3

[0559] Polypropylene -

[0560]

[0561] 94.3 95.5

[0562] PP (IR)

[0563] Polyamide -n 9

[0564] 0.1 0.1

[0565] PA (IR), wt.-%

[0566] Polystyrene - „7

[0567] <LOD 0.1

[0568] PS (IR), wt.-%

[0569] Chalk (IR), wt.-% 0.1 0.1 0.1

[0570] Ash content (TGA), „7

[0571] 0.61 0.51

[0572] wt.-%

[0573] PE (IR) 6 5 4

[0574] C2 total (Crystex),

[0575]

[0576] 3.05 3.2

[0577] wt.-%

[0578] C2(CF) (Crystex)

[0579]

[0580] 2.66 3.18C2(SF) (Crystex),

[0581]

[0582] 9.03 9.07

[0583] wt.-%

[0584] IV(CF) (Crystex),

[0585]

[0586] 2.04 2.03

[0587] dL / g

[0588] IV(SF) (Crystex),

[0589]

[0590] 0.86 0.86

[0591] dL / g

[0592] soluble fraction (SF)7 9„

[0593] 6.34 6.14

[0594] (Crystex), wt.-%

[0595] crystalline fractionq9 7

[0596] 93.66 93.86

[0597] (CF) (Crystex), wt.-%

[0598] n.m. = not measured

[0599] As depicted in Table 4, it is remarkable that the polymer blends of the blends PP1 and PP2 are characterized by a lower content of non-polyolefin polymeric compounds and inorganic compounds as compared to the comparative PP3. The intrinsic viscosity in the soluble fraction of the polymer blend was also reduced in the inventive examples versus the comparative example.

[0600] Table 5: Metal content of the polymer blend.

[0601] Metal content (XRF,

[0602] PP3 PP1 PP2

[0603] ppm)

[0604] Heavy metals

[0605] 0 0 0

[0606] (sum of Cd, Cr, Hg, Pb)

[0607] Al 287 112 91

[0608] Ca 1151 945 730

[0609] Fe 60 57 41

[0610] P 127 84 82

[0611] S 41 36 27

[0612] Si 496 439 341

[0613] Ti 2248 1393 1038

[0614] Zn 34 35 30

[0615] Table 5 further shows that the metal content was very low in blends PP1 and PP2. In particular, significant reduction of the content of titanium (Ti), aluminum (Al) and calcium (Ca) was observed for the inventive examples versus the comparative example.Table 6: Inclusions in the polymer blend.

[0616] Inclusions (X-ray CT, vol.-%) PP3 PP1 PP2

[0617] High density (total) 0.09 0.08 0.05

[0618] High density >50pm 0.05 0.04 0.02

[0619] High density >100pm 0.03 0.02 0.01

[0620] Low density (total) 0.40 0.26 0.18

[0621] Low density >50pm 0.24 0.12 0.08

[0622] Low density > 100pm v% 0.13 0.07 0.04

[0623] High + low density (total) 0.48 0.34 0.23

[0624] High + Low density >50pm 0.29 0.16 0.10

[0625] High + Low density >100pm 0.15 0.09 0.05

[0626] According to Table 6, the inclusion observed by X-ray CT in the polymer blends were reduced in both blends PP1 and PP2 versus the comparative blend PP3.

[0627] Table 7: Physical properties of the polymer blends

[0628] PP3 PP1 PP2

[0629] MFR 230°C / 2.16kg,

[0630] 8.15 7.36 7.1

[0631] g / 10 min

[0632] Flexural Modulus ISO

[0633] 178 / specimen type B, 1166 ± 10 1144 ± 13 1167 ± 13

[0634] MPa

[0635] Eta(0.05rad / s), 200°C,

[0636] 3812 4311 4056

[0637] Pa.s.

[0638] Eta(300rad / s), 200°C,

[0639] 268 302 296

[0640] Pa.s.

[0641] Shear Thinning Factor

[0642] (STF), 14.2 14.3 13.7

[0643] Eta(0.05) / Eta(300)

[0644] According to Table 7, many of the physical properties were in the same range.

[0645] Finally, it is remarkable that the results obtained for the two example blends PP1 and PP2 were comparable, regardless the fact that in PP2 a precursor mixed-plastic recycling stream (A) was used that was already enriched in post-consumer flexible polypropylenearticles. This supports the efficiency of the process in contaminant removal and its applicability for a variety of post-consumer waste products.

[0646] Example 1

[0647] A three layer BOPP film was prepared as follows.

[0648] The compositions were prepared based on the recipes indicated for PP1 to PP3 above by compounding in a co-rotating twin-screw extruder Coperion ZSK 40 at 220 °C.

[0649] Prior to conversion, the recycled polypropylene pellets with composition of PP1 and PP2 were dried for 4h at 90°C for IE1 to IE6. The recycled polypropylene pellets with composition of PP3 were aerated for 22h at 120°C for CE1 to CE3.

[0650] RE1, IE1 to IE6 and CE1 to CE3 are 3-layer films (ACE - 10:80:10 ratio) prepared according to the layer recipes given below. Precursor cast films were extruded with a thickness of nearly 800 - 850 pm, by using a twin screw extruder for the core layer and a single extruder for the skin layers. 8.5 x 8.5 specimens were cut from the resultant precursor films.

[0651] These specimens were biaxially stretched on a laboratory stretching machine from Bruckner Maschinenbau GmbH, Germany. The stretching-process was done at a strain rate of 400% / s and temperature of 155°C.

[0652] The films were stretched at a 5x9 ratio (MDxTD), the final thickness of the films was was approx. 16 pm

[0653] As materials for preparing the film layers for the BOPP film, the following polypropylene grades were used:

[0654] PP4 is a propylene terpolymer, i.e. C3C2C4 terpolymer that corresponds to the terpolymer used in inventive example IE2 and comparative example CE2 of WO 2018 / 069263 A1, based on a non-phthalate Ziegler-Natta catalyst as described for example in WO 2012 / 007430 A1.

[0655] PP4 has the following properties:

[0656] MFR2(230 °C) of 7.1 g / 10 min,

[0657] C2 content of 1.0 wt.-%,

[0658] C4 content of 8.9 wt.-%,

[0659] Tm of 131 °C,Tc of 92 °C, and

[0660] Tg of -2 °C.

[0661] PP5 is a polypropylene homopolymer produced by Borealis AG. PP5 has the following properties:

[0662] MFR2(230 °C) of 3.2 g / 10 min,

[0663] Pentad isotacticity ([mmmm]) of 92.4% and free from 2,1 -regiodefects,

[0664] Tm of 162 °C,

[0665] XCS of 3.0 wt.-%, and

[0666] Mw / Mn of 6.78.

[0667] In the casting process, a three layer cast film was obtained having the following cast film structure:

[0668] * Total film thickness appr. 800 - 850 pm

[0669] • Skin layers: 100% PP4

[0670] * (thickness appr. 75 - 85 pm each)

[0671] • Core layer: 100 wt.-% of recycled blend PP1 or PP2 or varying proportions of PP5 and PP1 / PP2

[0672] As a reference example pure PP5 was used.

[0673] The obtained BOPP film structure had a total film thickness of 15 to 20 pm and a layer ratio of skin:core:skin of 10:80: 10.

[0674] The recipes of the obtained BOPP core layer containing the mixed-plastic polypropylene recycling blend (PP1, PP2 (both IE) or PP3 (CE)) are shown in Table 8 below. Weight percent is given for the recycled blend, adding to 100 wt.-% by corresponding proportion of PP5.Table 8: BOPP density

[0675] Composition of the core layer

[0676] 100 % PP5 (reference) RE1

[0677] 36% PP3 CE1

[0678] 60% PP3 CE2

[0679] 100% PP3 CE3

[0680] 36% PP1 / 64% PP5 IE1

[0681] 60% PP1 / 40% PP5 IE2

[0682] 100% PP1 IE3

[0683] 36% PP2 / 64% PP5 IE4

[0684] 60% PP27 40% PP5 IE5

[0685] 100% PP2 IE6

[0686] All inventive example IE1 to IE6 comprising the PP recycled blend of the invention exhibited a higher density than the comparative examples CE1 to CE3 comprising colored PP recycled fraction PP3 as described above.

[0687] In addition, IE1 and IE4 comprising 36 wt.-% of the PP recycled blend of the invention in the core layer (30 wt.-% in the total film) showed a surprisingly high layer density close to the reference virgin PP5 material.

[0688] Example 2

[0689] The films according to RE1 and IE7 are 5-layer films (ABCDE - 5:15:60:15:5 ratio) prepared according to the recipes given below using a BOPP pilot line of Bruckner Maschinenbau (i.e. combined extrusion and stretching apparatus).

[0690] The extrusion module was set to produce 800 pm films. The films were stretched at a 5x9 ratio (MDxTD). The final film thickness was approx. 25 pm.

[0691] With the same conditions of a pilot line a five layer BOPP film was prepared having the following film structure:

[0692] Total film thickness: appr. 25 pm

[0693] Skin layer: 1.25 pm PP4

[0694] Intermediate layer: 3.75 pm PP5Core layer: 15 pm 100 wt.-% PP5 (RE1) or 50 wt.-% PP5 + 50 wt.-% PP2 (IE7; appr. 30 wt.-% of PP2, based on the total film weight)

[0695] Even with the replacement of 50% of the virgin polypropylene PP5 (RE1, taken as a reference material) by a recycled polypropylene blend PP2 according to the present invention a relatively high density comparable to the pure virgin PP can be obtained. Very low amount of inclusions and film defects in the BOPP core layer comprising the recycled blend are obtained.

[0696] Example 3

[0697] The examples RE1, CE1-CE3 and IE1-IE6 were subjected to optical parameter measurements of clarity haze and transmittance as described in the experimental section above. The properties were measured on the total multilayer BOPP film as produced in Example 1. The results are shown in Table 10 below.

[0698] Table 9

[0699] Composition # Clarity (%) Haze (%) Transmittance (%)

[0700] 100 % PP5 (reference) RE1 95.7 1.23 94.14

[0701] 36% PP3 CE1

[0702] 60% PP3 CE2 77.3 28.33 83

[0703] 100% PP3 CE3 68 42.28 76.33

[0704] 36% PP1 / 64% PP5 IE1

[0705] 60% PP1 / 40% PP5 IE2 90 9.8 89.88

[0706] 100% PP1 IE3 84.3 13.97 88.68

[0707] 36% PP2 / 64% PP5 IE4 94.3 4.77 92.25

[0708] 60% PP2 / 40% PP5 IE5 92.2 7.56 91.32

[0709] 100% PP2 IE6 87.7 10.92 90.28

[0710] It is evident that all inventive example IE1 to IE6 comprising the PP recycled blend of the invention exhibited improved optical values over the comparative examples CE1 to CE3 comprising colored PP recycled fraction PP3, as described above.

[0711] In addition, IE1 and IE4 comprising 36 wt.-% of the PP recycled blend of the invention in the core layer showed surprisingly high values for clarity and transmittance as well as surprisingly low values for haze close to the reference virgin PP5 material.

[0712] The results of Table 9 are illustrated in the graph according to Fig.1 as well.Further, Fig. 2 shows the optical effects of the inventive samples over the comparative samples. While the images according to CE1 -CE3 appear unclear and blurred, the images according to IE1-IE6 are clear, bright and have a greater visual appearance.

[0713] Example 4

[0714] The core layer of the five layer BOPP film prepared as described in Example 2 having the composition of RE1 and the composition of IE7 was subjected to measurement of gloss measured at an angle of 45° in machine direction (MD) and in transverse direction (TD) according to ASTM D2457 and determined as described in the experimental section above. Results of the gloss of the core layer are shown in Table 10 below.

[0715] Table 10: Optical properties of BOPP core layer

[0716]

[0717] The results show that with the replacement of 50% of the virgin polypropylene PP5 by a recycled polypropylene blend PP2 according to the present invention a BOPP film layer having advanced optical properties could be obtained. The deterioration by replacement of the pure virgin PP by the recycled blend of the invention could be minimized. This result shows the very low amount of inclusions and film defects in the BOPP core layer comprising the recycled blend.

Claims

Claims1. Biaxially oriented polypropylene film comprising at least one layer which comprises a polypropylene composition (PC), wherein the polypropylene composition (PC) comprises a mixed-plastic polypropylene recycling blend having:i) a polypropylene content of from 92 to 99.7 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend and determined by Fourier-transform infrared (FTIR) spectroscopy as described in the specification;ii) a melt flow rate MFR2 in the range of from 3 to 10 g / 10 min, determined according to ISO 1133, 230 °C, 2.16 kg;Hi) a content of inclusions of a density of at least 1.1 g / cm3of up to 0.45 vol.-%, wherein the content of inclusions of a density of at least 1.1 g / cm3and equal to or lower than 1.53 g / cm3is in the range of from 0.01 to less than 0.40 vol.- %, the contents of inclusions being indicated relative to the total volume of the mixed-plastic polypropylene recycling blend and determined by X-ray Computed Tomography (X-ray CT) as described in the specification; iv) a sum of contents of contaminants selected from polyamide, polystyrene, and chalk of less than 1.0 wt.-%, relative to the total weight of the mixed- plastic polypropylene recycling blend, and being determined by Fourier- transform infrared (FTIR) spectroscopy as described in the specification; andv) a content of soluble fraction (SF) in the range of from 3.0 to 12.0 wt.-%, relative to the total weight of the mixed-plastic polypropylene recycling blend, wherein the soluble fraction (SF) has an intrinsic viscosity (IV(SF)) of below 1.1 dl / g, the content of soluble fraction (SF) and the intrinsic viscosity (IV(SF)) being determined according to CRYSTEX QC analysis as described in the specification.

2. The biaxially oriented polypropylene film according to claim 1, wherein the polypropylene composition (PC) additionally comprises a virgin propylene polymer (v-PP).

3. The biaxially oriented polypropylene film according to claim 1 or 2, wherein polypropylene composition (PC) comprises:a) from 20.0 to 100.0 wt.-%, relative to total weight of the polypropylene composition (PC), of said mixed-plastic polypropylene recycling blend, and b) from 0.0 to 80.0 wt.-%, relative to total weight of the polypropylene composition (PC), of said virgin propylene polymer (v-PP).

4. The biaxially oriented polypropylene film according to any one of claims 1 to 3, wherein the film comprises at least 20 wt.-% of said mixed-plastic polypropylene recycling blend, based on the total weight of the film.

5. The biaxially oriented polypropylene film according to any one of the preceding claims, which is a multilayer film.

6. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein said at least one layer comprises from 25 to 100 wt.-% of said mixed plastic polypropylene recycling blend, based on the total weight of said at least one layer.

7. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein the film comprises a core layer C and at least external layers E1 and E2, wherein the core layer C comprises from 25 to 100 wt.-% of said mixed plastic polypropylene recycling blend, based on the total weight of the core layer.

8. The biaxially oriented polypropylene film according to any one of the preceding claims 2 to 7, wherein the virgin propylene polymer (v-PP) is selected from propylene homopolymers, heterophasic polypropylenes, and propylene random copolymers.

9. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein the mixed plastic polypropylene recycling blend is obtained from a transparent fraction of a mixed polypropylene post-consumer waste (PCW) feedstock.

10. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein the film has a density of at least 0.880 g / cm3, measured according to DIN EN ISO 845.

11. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein the mixed plastic polypropylene recycling blend has an ashcontent, determined as described herein, of not more than 1.0 wt.-%, based on the total weight of the mixed plastic polypropylene composition, and / or a flexural modulus according to ISO 178 (method A, type B specimen) and determined as described herein in the range of 1050 to 1350 MPa.

12. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein the film has a clarity, determined according to ASTM D1003 and as described herein, of at least 81 %, and / ora haze, determined according to ASTM D1003 and as described herein, of not more than 16.5 %, and / ora transmittance, determined according to ASTM D1003 and as described herein, of at least 85.0 %.

13. The biaxially oriented polypropylene film according to any one of the preceding claims, wherein the film has a gloss measured at an angle of 45° in machine direction (MD) according to ASTM D2457 and determined as described herein of at least 80 %, and / ora gloss measured at an angle of 45° in transverse direction (TD) according to ASTM D2457 and determined as described herein of at least 80 %.

14. Use of a biaxially oriented polypropylene film according to any one of the preceding claims 1 to 13 for packaging, labelling, medical or optical applications.

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