Ballistic separation of caps and closures

Abstract

The present invention, is a sorting and processing method for post consumer waste from caps and closures, namely derived from caps and closures from still mineral water (SMW) and carbonated soft drink (CSD) applications from beverage packaging, with a ballistic separation by means of different weight due to different material and modality. The method comprises further sorting, washing, optional color sorting, shredding and recovering of the initial solid waste material, to obtain a purified recyclate for re-use in an almost close-loop system again for beverage packaging and drinking applications with improved properties.

Description

BALLISTIC SEPARATION OF CAPS AND CLOSURES

[0001] The present invention discloses a process and method to process mixed consumer waste, consisting of caps and closures e.g. from beverage packaging, made from all sorts of polyolefins, to achieve a better, meaning purer starting material, to be processed by re-processing and re-using, in further caps and closures applications.BACKGROUND OF THE DISCLOSURE

[0002] In light of the growing environmental concern and the imperative to foster sustainable solutions, there exists a critical need to address the recycling of plastic applications from consumer applications especially bottles and their lids, namely caps and closures. The composed materials mainly comprise PE (polyethylene), and PP (polypropylene).

[0003] Some sorting and recycling systems are so inefficient that the processes of recovering, processing and recycling the recyclable polyolefins derived from post consumer waste sources require more energy than could be saved by simply using virgin grade material for the same applications.

[0004] In the state of the art, there are different sorting methods already known for different waste streams comprising post consumer polyolefins.

[0005] “The microsortation of high loadings of post-consumer mixed polyolefins using liwuid carbon dioxide in a slightly agitated batch apparatus” Enick, R. et al. (1997), Resources, Conservation and Recycling, 20, 143-15, is the microsorting of post consumer polyolfin waste described, using near- critical carbon dioxide as a float-sink medium.

[0006] A “Closing the loop on bottle caps” is already available, which (27 Sep. 2023; “https: / / www.tomra.com / en / waste-metal-recycling / media-center / news / 2023 / closing-in-the-loop-on- bottle-caps”) describes the mechanical sorting process to close the loop for food-grade cap-to-cap recycling.

[0007] In the existing state of the art, a persistent drawback arises from the impurity of post-consumer recycled materials, resulting in compromised quality in second-life applications. The discernible need for improved, material-specific, uncontaminated and “pure” feedstock prompts ongoing developments. Its innovation seeks to address a still growing critical demand for offering sorted and purer feedstock and base materials, facilitating closed-loop applications with heightened quality standards, especially in the realm of post consumer plastic waste.

[0008] Reclaiming of articles from consumer applications such as bottle reclamation schemes to collect all type (still mineral water / drinks - SMW, carbonated soft drinks - CSD) of beverage packages and bottles. Preferably made of PE and PP, PE bottles contain mono- and multimodal homo- andcopolymers and a collection of different materials in varying share will find itself in reclaimed recycled collection of PC waste. Material properties of recycled PE (rPE) of such quality will compromise blends molten from this collection compared to virgin PE (vPE) for manufacturing articles.

[0009] So, PE homo- and copolymers can hardly get differentiated by high-throughput analytical techniques such as UVvis, FT(N)IR, but separation and sorting of the different materials is mandatory to obtain a high quality recycled material.

[0010] The feedstock often exhibits varying compositions due to the diverse range of products and waste discarded into the recycling streams. This variability arises from the assortment of materials collected, which can include plastics from different sources, colors, grades and contamination levels. As a result, the second life applications of the recycled feedstock, suffer always from the initial inconsistent compositions compromising the quality of the products.

[0011] Hence, there is a pressing need for cost-efficient and sustainable processes, to recycle post consumer waste for high quality applications. So, this demand underscores the importance of developing innovative methods and processes that not only prioritize efficiency but also contribute to a more environmentally friendly and resource-efficient approach to meet the requirements for superior product processing.SUMMARY OF INVENTION

[0012] So, the method and process disclosed herein overcomes the drawbacks known from the state of the art and provides a solution to the addressed problems and issues of compromised quality of recycled polyolefins. It has surprisingly been found, that by separating the caps and closures before shredding them, by material using the different specific weight, an enriched solid waste comprising mainly PE or PP etc. of higher quality and less impurities of other materials can be obtained.

[0013] So, this process reclaims post consumer waste comprising caps and closures from all type of beverage packaging and bottle (still mineral water / drinks - SMW, carbonated soft drinks - CSD), namely caps and closures to sort and separate them, before shredding the waste to flakes as it is well known from the state of the art, washing or color sorting steps etc. are applied, providing enriched components comprising the different materials from the initial unshredded mixed waste stream derived from post consumer beverage packaging and drinking applications.

[0014] So, provided is a method for sorting and processing mixed solid waste, comprising an initial mixed post consumer waste, consisting of caps and closures derived from beverage packaging drinking applications, namely still mineral water / drinks (SMW) and carbonated soft drinks (CSD) and applications, comprising, prior or and after to subsequent further processing steps, such as washing or shredding and the like:A) A sorting step, comprising a) providing the mixed waste solid waste, in a stream consisting of caps and closures comprising at least 50 wt% of high density polyethylene waste having a density greater than 0.935 g / cm3and less than 0.970 g / cm3, and / or less than 30 wt% of polypropylene having a density in the range of approx. 0.9 g / cm3, and less than 30 wt% of PET, having a density in the range of 1 .3 to 1 .45 g / cm3, and less than 10 wt% mixed waste, wherein the waste comprising different polyolefin derived caps and closures are applied comingled; b) sorting the caps and closures by weight, comprising an appropriate air flow, to divide the caps and closures by weight, c) sorting the caps and closures by material due to their specific weight, comprising an appropriate air flow, to divide the caps and closures by weight, d) separating the different caps and closures by modality, material and weight using at least two mechanical separators including a size separator and a density separator to produce separated waste stream enriched at least in carbonated soft drinks (CSD) and still mineral water (SMW) caps and closures; e) obtaining at least two charges of separated waste, comprising enriched HDPE waste component and at least one other enriched waste component;B) A washing step, comprising a) a cold and or hot water wash step, used to remove odor components originating from food degradation and / or microbial activity from the separated caps and closures, and a b) an optional further treatment with detergents;C) Optional a color sorting step, comprising a) sorting process by an optical sorter system equipped with RGB cameras and LED arrays, b) Wherein the accuracy of the sorting can be calculated, as the ratio of the well-recognized samples on the total number of all samples;D) A shredding step, comprising an agglomerated shredder for shredding the separated, washed and sorted intermediate components, to obtain flakes for further processing;E) A recovering step, comprising at least two recyclable materials as individual enriched recyclable products, compared to the initial mixed solid waste.DETAILED DESCRIPTION

[0012] In the context of the present disclosure repetitions of individual sorting and processing steps of the process as described herein are encompassed, and the sequence of steps can also be varied arbitrarily.

[0013] The present disclosure relates to a method for sorting and processing mixed solid waste, comprising an initial mixed post consumer waste, consisting of caps and closures derived from beverage packaging and drinking applications, namely still mineral water / drinks (SMW) carbonated soft drinks (CSD) and applications, comprising, prior or after to subsequent further processing steps, such as washing or shredding and the like:A) A sorting step, comprising a) providing the mixed waste solid waste, in a stream consisting of caps and closures comprising at least 50 wt% of high density polyethylene waste having a density greater than 0.935 g / cm3and less than 0.970 g / cm3, and / or less than 30 wt% of polypropylene having a density in the range of approx. 0.9 g / cm3, and less than 30 wt% of PET, having a density in the range of 1 .3 to 1 .45 g / cm3, and less than 10 wt% mixed waste, wherein the waste comprising different polyolefin derived caps and closures are applied comingled; b) sorting the caps and closures by weight, comprising an appropriate air flow, to divide the caps and closures by weight, c) sorting the caps and closures by material due to their specific weight, comprising an appropriate air flow, to divide the caps and closures by weight, d) separating the different caps and closures by modality and weight using at least two mechanical separators including a size separator and a density separator to produce separated waste stream enriched at least in still mineral water (SMW) and carbonated soft drinks (CSD) caps and closures; e) obtaining at least two charges of separated waste, comprising enriched HDPE waste component and at least one other enriched waste component;B) A washing step, comprising a) a cold and or hot water wash step, used to remove odor components originating from food degradation and / or microbial activity from the separated caps and closures, and a b) an optional further treatment with detergents;C) Optional a color sorting step, comprising a) A sorting process by an optical sorter system equipped with RGB cameras and LED arrays, b) Wherein the accuracy of the sorting can be calculated, as the ratio of the well-recognized samples on the total number of all samples;D) A shredding step, comprising an agglomerated shredder for shredding the separated, washed and sorted intermediate components, to obtain flakes for further processing;E) A recovering step, comprising at least two recyclable materials as individual enriched recyclable products, compared to the initial mixed solid waste.

[0014] Especially beverage packaging and drinking applications, provided either in bottles for single use or multiple use applications, must provide good properties and need to fulfill different requirements when it comes to airtight mechanical stability. So, typically high density polyethylene and polypropylene are used for caps and closures, especially CSD (carbonated soft drinks) and SMW (still mineral water) applications. Besides that, the used mixed solid waste, is derived only from polyolefin application fulfilling the requirements of food approval. Which means that the mixed solid waste can comprise besides polyethylene, normally high density polyethylene, also polypropylene and polyethylene terephthalate.

[0015] So, caps and closures made of HDPE are differentiated in mono- and multimodal co- and homopolymers, which is also reflected in the specific weight. Carbonated soft drinks (CSD) caps in PET bottle packaging are usually higher in weight (typically ranging from 1.7 to 2.8 g / cap) compared to still mineral water (SMW) caps (approx. 1 .0 to 1 .4 g / cap), due to their specific different requirements.

[0016] Additionally, processes for separating PET from the mixed solid waste material, can be achieved by so called sink float methods. The method relies on the density difference between PET and other polyolefin materials present in the mixed solid waste stream. It’s a density based separation and can be applied either as unshredded or in shredded pieces, which are then mixed with water in a tank or basin. PET, being denser than water sinks to the bottom while lighter materials such as PP and PE float on the surface. Once the materials have separated based on their density, the PET sinks to the bottom of the tank or basin It is then collected using a conveyor belt, rake or other mechanical means. The floating materials, which may include PP and PE are skimmed off the surface of the water and separated for further processing or disposal. The collected PET can undergo additional processing steps to prepare it for recycling into new products. This step can also replace the washing step or be combined with any other washing step, to make the process as efficient and cost, time and energy saving as possible.

[0017] Besides that also recycling air-Classifier, or as Recycling whirlwind process referred to, is a method, used for separating different types of plastic based on their density. The process involves feeding mixed waste into a vertical chamber where it is subjected to a controlled airflow. As the materials, such as caps and closures fall through the chamber, the lighter plastic, meaning caps and closures with less weight as defined above, are carried upwards by the airflow while the heavier plastics fall downwards. By adjusting the airflow velocity and other parameters, the process can effectively separate plastics with different densities, such as PET, HDPE, and PP, from each other. This allows for efficient sorting and recycling of plastic waste streams.

[0018] According to the disclosed method, sorting of the caps and closures by weight, means also separating them not only according to their weight, lower weight being separated from higher weight, but also a separation of multimodal waste from monomodal waste, which is a higher weight component.

[0019] The difference in weight between still mineral water (SMW) and carbonated soft drinks (CSD) caps and closures made from HDPE can be attributed to variations in their structural composition. The caps are designed to meet specific requirements for their respective beverage types. Carbonated soft drinks (CSD) caps may incorporate additional features or materials to withstand the pressure from carbonation, resulting in denser and heavier cap compared to the simpler design of still mineral water(SMW) caps, which are intended for still beverages. These design variances contribute to the observed differences in weight.

[0020] Caps can are preferably made from PE and PP, each cap and closure is having a characteristic weight for instance in the field of still mineral water (SMW) and carbonated soft drinks (CSD) up to 3.3 g. The choice of material depends on the specific requirements and properties desired for the cap, influencing its weight and performance for still mineral water (SMW) and carbonated soft drinks (CSD) caps and closures. Therefore caps and closures derived from still mineral water (SMW) applications have higher weight than caps and closures derived from carbonated soft drink (CSD) applications in that field.

[0021] Caps and closures from non-drinking applications and non-beverage packaging sectors can also be sorted and processed using the method described here. It should be noted that closures from cosmetic applications such as shampoo and the like are naturally heavier and therefore differ in their specific weight.

[0022] Furthermore, a collection of different materials may be found in the mixed solid waste derived from caps and closures. The mixed solid waste provided in the initial waste stream of caps and closures comprises typically about 50 wt% of high density polyethylene, preferably 40 wt%, preferably 30 wt%, preferably 20 wt%, preferably 18 wt%, most preferably at least 15 wt% based on the overall weight of the initial mixed solid waste. Typically the share of HDPE used in caps and closures, having a density greater than 0.953 to 0.963 g / cm3.

[0023] In the mixed solid waste each component, preferably 10 to 90 % of PE (including LDPE,MDPE, HDPE), 20 to 80% of PP, 30-70% PET, and at least one other component such as paper, metal, glass etc. wherein each share of each component sums up to 100 wt%.

[0024] The amount of polyethylene (including LDPE, MDPE, HDPE) in the initial mixed solid waste material is at least 30 wt%, preferably 40 wt%, preferably 50 wt%, preferably 60 wt%, preferably 70 wt%, preferably 80 wt%, preferably 90 wt%.

[0025] The amount of polypropylene in the initial mixed solid waste material is about 30 wt% preferably 25 wt%, preferably 20 wt%, preferably 15 wt%, preferably 10 wt%, preferably 5 wt%. Wherein PP used in caps and closures is normally having a density of approximately 0.9 g / cm3, in more detail in the range of 0.895 to 0.920 g / cm3.

[0026] So, the amount of polyethylene terephthalate (PFT) is about 30 wt% in the initial mixed solid waste, preferably 25 wt%, preferably 20 wt%, preferably 15 wt%, preferably 10 wt%, preferably 5 wt%.

[0027] The method wherein the mixed waste comprises at least 55 wt% of HDPE and at least 45 wt% of others.

[0028] The mixed waste comprises high density polyethylene present in the range of 30 to 90 wt%, preferably present in the range of 40 to 80 wt%, preferably present in the range of 50 to 70 wt%, most preferably at least 55 wt% of HDPE.

[0029] Other polyolefins comprised in the mixed waste are present in the range 10 to 70 wt%, preferably present in the range of 20 to 60 wt%, preferably present in the range of 30 to 50 wt%, most preferably at least of 45 wt% of other polyolefins.

[0030] Available sources of post consumer waste are typically not pure and can vary depending on the source of the post consumer waste, and can comprise further non caps and closure material which shall be less than 10 % mixed plastic waste or non plastic components, comprising also residues of non-further processable components, such as compostable waste, paper, metallic components etc.

[0031] Surprisingly it has been found, that the initial solid waste stream comprising different polymer derived caps and closures can be applied comingled and can be sorted by weight, comprising an appropriate air flow, to divide the caps and closures by weight and material, due to their specific weight, separating the different caps and closures by modality, material and characteristic and specific weight using at least two mechanical separators including a size separator an optical separator or a density separator to produce separated waste stream enriched at least in carbonated soft drinks (CSD) and still mineral water (SMW) caps and closures, wherein at least two charges of separated waste components are separated and obtained, comprising at least an enriched HDPE waste component and at least one other enriched waste component, besides not wanted residues, not being applicable in further recycling processes. Residues can be further processed by all types of methods known in the state of the art. Such as PS impurities may be resolved in a soluble, such as Toluol and be removed from the residues. Metallic components are easy to be separated by using magnetic separation methods., furthermore cyclone with sieves and trommels for separating iron and the like from plastics.

[0032] Typical optical sorters upon detecting a particular material, such as HDPE and PP in the initial mixed solid waste uses air directed through nozzles to eject the targeted / identified material to produce one or more material enriched components, such as HDPE, PP and PET which may be further processed and reused as recyclable PP, recyclable PET, recyclable HDPE.

[0033] For this application any optical sorter known in the art can be used. For example, the optical sorter can operate by scanning the intermediate waste stream in a free fall using a camera sensor. The camera sensor detects the material and then air jets may quickly eject the material while in free fall.

[0034] The method and process described herein can separate significantly large percentages of different types materials from the mixed solid waste stream derived from caps and closures as compared to known systems, to improve the recycled quality of further second life applications. This ability is due in large part to the weight separation and density separation, which creates concentrated, homogenous, material-separated waste components from which further processing of the enriched starting material secures higher quality in recyclates fur further caps and closures applications.

[0035] As all colors possible can be found in caps and closures, a color sorting step is appropriate. The color sorting step may comprise the classification into six main classes of colors (white, blue, green, red, orange and yellow) were identified and further subdivided in 14 sub-classes based on color tones (e.g., two types of white, four types of blue, three of green, one of red, two of orange, and two of yellow). So for each run, one class of color and the linked subclasses as well, to separate all caps, which belong to that group. The non-selected remains are again processed to pick another color classification to continuously separate by each run one class of color.

[0036] Unlike traditional mechanical sorting derived waste sources, the method and process of the invention sorts and separates the initial solid waste provided in form of collected caps and closures prior to shredding etc. sufficiently to obtain enriched and concentrated homogenous intermediatecomponents of one specific material for efficient further processing of one material to improve the quality and property of the so obtain recyclates.

[0037] Furthermore as an additional step a color sorting step based on the LAB method can be applied to improve further the quality of the sorted caps and closures. Based on the color properties the material, namely the caps and closures of one material, to be sorted is illuminated with a light source, typically a high-intensity LED light. The light reflects off the surface of the material, and the color information is captured by sensors. As the material moves along a conveyer belt, compressed air jets are used to blow off individual pieces that do not meet the desired color criteria. This allows for precise sorting based on color differences. The sorted material is then directed onto separate belts or chutes based on its color classification. This results in a further improvement of quality of the sorted material, based on their color characteristics. In the sense of the present invention such color sorting steps can be applied several times, preferably 6-8 cycles, as the LAB method provides an efficient and accurate way to sort materials based on color, allowing for the separation of materials with different color properties for recycling or other purposes.

[0038] The method described herein provides extracting a plurality of different recyclable materials from the initial mixed solid waste stream using one or more mechanized sorting apparatuses.

[0039] The sorting step of the initial mixed solid waste is performed using appropriate air flow separators, dimensional sorters such as ballistic separators, angled disc screens followed by optical sorters.

[0040] To ensure high quality in the obtained material enriched components, additional steps of sorting of the initial mixed solid waste can be included prior to the initial sorting steps according to (A), by separating the caps and closures divided in polyethylene (PE), polypropylene (PP) to discard nondesired materials.

[0041] The components of the initial solid waste stream are separated by density to produce waste streams that are individually enriched in at least two recyclable materials, such as HDPE and at least another, e.g. PP or PET. Although not required, the density separation is preferably performed in a separate apparatus downstream from the size separator. Downstream density separation allows distinct density separators to be used on individual sized fractions, which allows the individual density separators to be configured for particular materials and streams. The density separator units may be calibrated to provide separation between particular materials in the mixed solid waste stream comprising caps and closures. Density separation can be used to separate different types of materials such as HDPE, PP, and PET, thereby enriching one or more particular enriched intermediate streams in at least two different types of recyclable materials.

[0042] Furthermore, the sorting apparatus may be a dimensional sorter such as a 3D sorting apparatus. Examples of 3D sorters include ballistic separators and / or screens or optical sorters configured and equipped to separate the caps and closures by weight and material, as the initial mixed solid waster material comprises only three-dimensional items. Optionally two or even more ballistic separators and / or screens can be used in series or parallel. The dimensional separators can be used to recover at least two materials that are comingled with another material having a different density, and also similar dimensions, but differ in their characteristic and specific weight. The caps and closuresgenerally have a thickness less than 5 mm. In addition, a further step comprising a 2D-separator can be used to separate non polymer derived waste components, such as paper, metal, wood and the like.

[0043] According to the present disclosure, the initial mixed solid waste is derived from caps and closures comprising and including all kinds of caps and closures made of recyclable polymers, which means that caps and closures also include tethered and elongated and non-tethered and nonelongated caps and closures.

[0044] Furthermore the sorting step comprises further a mechanical sorter including a weight separator which comprises an air drum separator adapted for use in the system for separating solid waste by weight for sorting the initial mixed solid waste derived in a stream.

[0045] The method and process disclosed herein further comprises a washing step (B) of the sorted mixed solid waste stream comprising a cold and / or hot water wash step, used to remove odor components originating from food degradation and / or microbial activity from the separated caps and closures, and optional, further treatment with detergents when needed, and further a drying step after step washing of the material. The washing step also contributes to a quality improvement of the material to be recycled, meeting also necessary quality and safety standards as the material of the sorted components is suitable for food packaging,

[0046] Furthermore, a color sorting step (C) is performed after the initial material is sorted by weight. Comprising a further step of optical sorting to form a recovered stream separated by colors even improves the quality of the recyclate further. Sorting each of material-enriched intermediate components further by color enhances the quality, as typically recycled materials become gray or visually unappealing due to different colors, limiting their further applications. Therefore, a color sorting step is highly advantageous. RGB cameras and LED arrays can be used as optical sorter. The optical sorter may be configured to separate and distinguish each color from another. For example an optical sorter can be configured to recover the typical colors such as white derived from SMW caps from colored CSD applications such red or green or the like. There are many types of optical sorter technologies, including, but not limited to; Near Infrared (NIR), camera color sorters, X-Ray, etc. The optical sorter upon detecting a particular color uses air directed through nozzles to eject the targeted / identified material to produce one or more components, sorted by material and color. There are also optical sorters that utilize near infrared, X-Ray and other scanning technologies to separate targeted materials from mixed streams. Any number of optical sorters can be used in series or parallel. Manufacturers of optical sorters include TiTech Pellenc, MSS, NRT and others.

[0047] Optionally, the methods can also include metering the mixed solid waste streams and material enriched separated intermediate waste streams throughout the system to achieve a desired mass flow and burden depth. Furthermore, the comminution apparatus, size separator, density separator, and / or mechanized sorters are separated by one or more conveyors that have variable speed controls.

[0048] The variable speed control can be set to optimize the mass flow through the comminution apparatus, size separators, density separators, and / or mechanized sorters to optimize the quantity, purity, and / or value of the sorted materials being recovered from the mixed solid waste stream by ensuring a metered and evenly distributed presentation of material to the individual devices. One or more sensors positioned upstream, downstream, or within the at least tow of the material enrichedcomponents of the process can be used to monitor the separation efficiency, effectiveness, separation purity and / or rate of recovery of the caps and closures.

[0049] To evaluate the purity of the obtained components, material enriched, the components must comprise at 90 wt%, preferably 95 wt%, preferably 99 wt% of PE or PP, respectively. The enriched components comprise >80 wt%, preferably >90 wt%, preferably >95 wt% preferably >99 wt% of enriched individual components (based on the total weight of the incoming material, the mixed solid waste Measured by different sensors known in the state of the art. So the impurities are less than 5 wt% of the obtained individual enriched components.

[0050] The quality and these values can then be used to optimize or maximize one or more parameters of the system such as quantity and purity. Examples of sensors that can be used to control the flow rate of the mixed solid waste streams include level sensors such as, but not limited to optical sensors and / or ultrasonic sensors that measure the height of material building up on a conveyor and / or upstream of a metering device and / or that measure open space on a belt. A belt, metering device, or other piece of equipment can be sped up or slowed down using the sensor data to ensure that a flow rate or desired burden depth is achieved on a belt or in or through a piece of processing equipment (e.g., size separators) and / or any other portion of the system described herein. Other sensors include mechanical switches that are physically actuated by the waste stream building up beyond a desired level (e.g., height), which actuates the mechanical switch to provide a signal that can then be used to regulate flow or burden depth. The speed of all metering equipment including; walking floors; conveyors; metering drums; shredders and grinders; air drum separators; screens of all types; vibratory feeders; metering feeder bins; load levelers; and other such devices can be controlled and adjusted via control systems and other devices in order to properly meter material through all portions of the invention. Furthermore, the metering can be critical to obtain the desired high recovery and purity of recyclable materials from mixed solid waste.

[0051] Furthermore, the method and process can also comprise a shredding step (D) of the sorted, washed and color sorted intermediate waste stream comprising the steps of shredding the material consisting of an enriched component of caps and closures obtained after being processed by steps A), B) and / or C) in a shredder, obtaining 2-dimensional and 3-dimensional recyclable material. The intermediate material, still provided in the form of caps and closures are typically shredded before further extrusion and melting for reasons of uniformity, as a shredding step ensures a more uniform and consistent feedstock, contributing to the overall quality of the recycled material. Smaller shredded pieces have larger surface area, facilitating quicker and more efficient melting during the extrusion process, which also helps to reduce processing time as it requires less energy during further extrusion steps. And prevents uneven distribution of material properties in the final product.

[0052] While extruding the shredded an optional blending step, with other components, fillers, colors, also with virgin material and of course recyclate origin can be melt blended into.

[0053] Further applications are preferably in the field of food packages, namely caps and closures of still mineral water (SMW) and carbonated soft drink (CSD) applications, which require that the obtained material is further injection moulded to obtain caps and closures, in food grade, fulfilling high requirements on quality and safety, provided by closed loops for a second life of recyclable polymers.

[0054] Furthermore, the initial solid waste material is not only comprising virgin grade materials but can also further comprise r-HDPE.

[0055] It is also in the sense of this invention, that each process step can be repeated, or subsequently following other steps. The sequence is not fixed; after the initial sorting step (A), any subsequent processing step can be combined arbitrarily or performed multiple times.

[0056] The main purpose of improving the quality of the feedstock from recycled polyolefins is to achieve food compatibility by implementing a closed loop. By collecting, sorting, enriching and processing caps and closures from the same application and making them suitable to apply them to fulfill the same purpose again, it is ensured that the quality of the products is high and that no materials are introduced into the recycling process, as disclosed herein, that do not have food approval. This helps maintain the quality and safety standards required for food-grade recycled materials, allowing for greater utilization of recycled content in caps and closures.

[0057] The method provided herein is a closed loop, suitable to obtain high quality recycled materials, such as r-HDPE (r-MDPE, r-LDEP) and r-PP to further process it to obtain articles such as caps and closures which are made from recycled material without any blending with virgin grades and fulfilling the food approval requirement.DEFINITIONS

[0058] In the sense of the present invention, various terms are defined as follows.

[0059] The term “HDPE” refers to a high density polyethylene polymer containing a homopolymer or copolymer of ethylene and one or more a-olefins polymerized in the presence of one or more single-site catalysts, such as one or more Ziegler-Natta catalysts, one or more metallocene catalysts, and combinations thereof. Such HDPE can have density within the range from 0.930 g / cm3to 0.970 g / cm3.

[0060] Within the scope of the present disclosure it can be understood that PE is not limited but also LDPE, MDPE and of course HDPE is likewise included as part of the invention. Differing in their density, as LDPE is ranging from 0.910 g / cm3to 0.940 g / cm3and MDPE ranges of 0.926 g / cm3to 0.940 g / cm3, the present process is also to be understood to include LDPE and MDPE and is not limited to HDPE.

[0061] The term “polyolefin” refers to polymers (including biopolymers or recyclates from post consumer waste or post industrial waste) formed from at least one simple olefin (with the general formula CnH2n) as a monomer, and includes both homopolymers and copolymers, (e.g., bipolymers, terpolymers, etc.), and blends thereof. In addition to that, they include polymers of ethylene (e.g. polyethylene), which include LDPE, LLDPE, MDPE, HDPE, copolymers of ethylene with one or more alpha-olefins, and blends thereof. They also include polymers of propylene (i.e., polypropylene), copolymers (e.g., bipolymers, terpolymers, etc.) of propylene with one or more alpha-olefins, and blends of different polyolefins. They also include polymers of butylene (i.e., polybutene), copolymers (e.g., bipolymers, terpolymers, etc.) of butylene with one or more alpha-olefins, and blends of different polyolefins.

[0062] The term “mixed solid waste” comprising caps and closures refers to a combination of various discarded materials that include caps and closures. These caps and closures are not solely derived from beverage packaging and drinking applications but can also originate from caps and closures used in other consumer goods. This waste stream encompasses a diverse range of plastic or metal caps and closures from a variety of packaging, containers, or products used by consumers made from all kinds of polyolefins.

[0063] Furthermore the mixed solid waste stream consisting of caps and closures is inherently variable in composition due to the diverse sources from which the post-consumer waste originates. It is contingent upon the discarded materials and varies accordingly, resulting in a wide range of compositions. As such, the proportion can significantly fluctuate, reflecting the dynamic nature of the waste stream and its dependency on disposal patterns.

[0064] In the sense of the present disclosure, PP waste refers to post consumer waste comprising a broad spectrum of caps and closures made from polypropylene (PP) materials. This includes caps and closures derived from all variations of PP, such as isotactic polypropylene, atactic or random propylene, besides the syndiotactic propylene. This waste stream encompasses a diverse array of used caps and closures collected from consumer products, packaging, and containers, reflecting the various compositions and structures of PP materials found in post-consumer sources.

[0065] High quality of recycled polyolefins means in the sense of the present invention, that the recyclate obtained from the process disclosed herein has food approval quality. Meaning that the initial mixed solid waste stream comprises only post consumer waste consisting from caps and closures from beverage packaging, and is not mixed or blended with non-food grade polyolefin material. Therefore the purity, processability and the quality of the obtained components are so high that the components can be used for applications with food grade requirements and production of e.g. caps and closures from beverage packaging without blending them with virgin material to improve processability.

Claims

CLAIMS1 . A method for processing mixed solid waste, comprising initial mixed consumer waste consisting of caps and closures, derived from beverage packaging and drinking applications, such comprising, prior or after to a subsequent further washing steps:A) A sorting step, comprising a) providing the mixed waste solid waste, in a stream consisting of caps and closures comprising at least 50 wt% of high density polyethylene waste having a density greater than 0.935 g / cm3and less than 0.970 g / cm3, and / or less than 30 wt% of polypropylene, and less than 30 wt% of PET, and less than 10 wt% mixed waste, wherein the waste comprising different polyolefin derived caps and closures are applied comingled; b) sorting the caps and closures by material due to their specific weight, comprising an appropriate air flow, to divide the caps and closures by material and weight, c) separating the different caps and closures by modality, material and weight using at least two mechanical separators including a size separator and a density separator to produce separated waste stream enriched at least in still mineral water (SMW) and carbonated soft drinks (CSD) caps and closures; d) obtaining at least two charges of separated waste, comprising enriched HDPE waste component and at least one other enriched waste component;B) A washing step, comprising a) a cold and or hot water wash step, used to remove odor components originating from food degradation and / or microbial activity from the separated caps and closures, and a b) an optional further treatment with detergents;C) Optional a color sorting step, comprising a) A sorting process by an optical sorter system equipped with RGB cameras and LED arrays, b) Wherein the accuracy of the sorting can be calculated, as the ratio of the well-recognized samples on the total number of all samples;D) A shredding step, comprising an agglomerated shredder for shredding the separated, washed and sorted intermediate components, to obtain flakes for further processing;E) A recovering step, comprising at least two recyclable materials as individual enriched recyclable products, compared to the initial mixed solid waste.

2. The method according to claim 1 , wherein sorting step (A) comprises additional steps of sorting of the initial mixed solid waste separating polyethylene (PE), polypropylene (PP), is separated prior to the sorting step (A).

3. The method according to claiml , wherein the mixed waste comprises HDPE in the range of 30 to 90 wt% of HDPE and at least 10 to 70 wt% of other polyolefins.

4. The method according to any of the preceding claims, wherein the sorting step of the mixed solid waste stream is performed by sorting the caps and closures by weight, wherein the separation by lower weight also means a separation of multimodal waste from higher weight derived from monomodal waste.

5. The method according to any of the preceding claims, wherein the mixed solid waste is comprising caps and closures, including all kinds of tethered and elongated caps and closures.

6. The method according to claim 1 , wherein the sorting step comprises a mechanical sorter including a weight separator which comprises an air drum separator adapted for use in the system for separating solid waste by weight and / or MFR.

7. The method according to claim 1 , wherein the washing step (B) of the sorted mixed solid waste stream comprises a a) washing step with either cold or hot water or both, b) washing steps with detergents, c) washing steps with further eluents being different from water, and d) a drying step after step c).

8. The method according to claim 1 , wherein the color sorting step (C) comprises optical sorting to form a recovered stream separated by colors, RGB cameras and LED arrays.

9. The method according to claim 1 , wherein the shredding step (D) of the mixed solid waste stream comprises the steps of a) Shredding the material obtained after being processed by steps A), B) and / or C) in a shredder, b) Obtaining 2-dimensional and 3-dimensional recyclable material.

10. The method of claim 1 , comprising a further step of processing the material obtained in step E), comprising the steps of a) Extruding the material, b) Optionally blending with other components, of virgin or recyclate origin, c) Injection moulding,d) Obtaining articles, such as caps and closures for CSD and SMW applications.

11. The method of any of the preceding claims, wherein the obtained enriched components comprise at least 90 wt%, preferably 95 wt%, preferably 99 wt% of HDPE, PP and / or PET, respectively.

12. The method of any of the preceding claims, wherein the method further comprise a step to separate metallic components.

13. The method of any of the preceding claims, wherein the method provides a closed loop, in that high quality recycled articles such as caps and closures are obtained.