[go: up one dir, main page]

WO2025228884A1 - Procédé de fourniture d'un mélange de recyclage de polypropylène et plastique mixte de haute pureté - Google Patents

Procédé de fourniture d'un mélange de recyclage de polypropylène et plastique mixte de haute pureté

Info

Publication number
WO2025228884A1
WO2025228884A1 PCT/EP2025/061523 EP2025061523W WO2025228884A1 WO 2025228884 A1 WO2025228884 A1 WO 2025228884A1 EP 2025061523 W EP2025061523 W EP 2025061523W WO 2025228884 A1 WO2025228884 A1 WO 2025228884A1
Authority
WO
WIPO (PCT)
Prior art keywords
polypropylene
recycling stream
stream
content
flexible
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/061523
Other languages
English (en)
Inventor
Alexandra Romina ALBUNIA
Bernadette DUSCHER
Baris KAYNAK
Peter Denifl
Paul Baumann
Manuel NUNEZ
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Borealis GmbH
Original Assignee
Borealis GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Borealis GmbH filed Critical Borealis GmbH
Publication of WO2025228884A1 publication Critical patent/WO2025228884A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene
    • C08L23/12—Polypropene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/0026—Recovery of plastics or other constituents of waste material containing plastics by agglomeration or compacting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/04—Disintegrating plastics, e.g. by milling
    • B29B17/0412—Disintegrating plastics, e.g. by milling to large particles, e.g. beads, granules, flakes, slices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0203—Separating plastics from plastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0268—Separation of metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0279—Optical identification, e.g. cameras or spectroscopy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0286—Cleaning means used for separation
    • B29B2017/0289—Washing the materials in liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2207/00—Properties characterising the ingredient of the composition
    • C08L2207/20—Recycled plastic
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present invention relates to a process for providing a mixed-plastic polypropylene recycling blend of high purity
  • the present invention relates to a process for providing a mixed-plastic polypropylene recycling blend characterized by high purity and beneficial physical properties.
  • Background During the last decades, concern about plastics and the environmental sustainability of their use in current quantities has grown. Polymers, 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. This has led to new legislation on disposal, collection and recycling of polymers. There have been efforts in several countries to increase the percentage of plastic materials being recycled instead of being sent to landfill.
  • Flexible polyolefin articles and therefore waste comprising these articles, are in general heavily printed, often metallized, large in surface area, and in contact with biological contaminations. These attributes result in a high contamination level, dark color, odor and emissions, which challenge mechanical recycling.
  • flexible polyolefin article feedstocks have a very heterogeneous composition. Thus, even with advanced sorting and washing technologies when recycling such feedstocks, impurities and residual inclusions can still remain at very high levels. Accordingly, removal of contaminants from flexible polyolefin article feedstocks generates problems in mechanical recycling. Therefore, the majority of recycling processes focuses on recycling of rigid polyolefin articles.
  • This process comprises a quality control step based on the analysis of the ethylene-propylene rubber (EPR) fraction of the soluble fraction, which has proven less convenient for application in high-load industrial recycling processes. Accordingly, there is a need for recycling processes for flexible polypropylene articles which provide recycled flexible polypropylene materials of good quality. For the further use of these materials, it is important that these materials are of high purity and good mechanical properties.
  • EPR ethylene-propylene rubber
  • the present invention addresses the above-stated need and provides a process for providing a mixed-plastic polypropylene recycling blend, the process comprising the following steps: 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); 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; c) removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C); 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
  • the present invention also provides a mixed-plastic polypropylene recycling blend obtainable or obtained by the process.
  • the present invention is based on the observation that a mixed-plastic polypropylene recycling blend having beneficial properties in terms of purity and mechanical characteristics can be obtained by a particularly designed recycling process comprising at least one particular quality control step. Due to its low content of contaminants as well as its good rheological and physical properties, the mixed-plastic polypropylene recycling blend obtainable or obtained by the process according to the present invention can be used in a huge number of different applications.
  • the present invention is directed to a process for providing a mixed-plastic polypropylene recycling blend, the process comprising the following steps: 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); 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; c) removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C); 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
  • the process comprises the following steps: 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); 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; c) removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C); 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); wherein steps c) and d) can be in any order, and if
  • the process comprises steps c) and d) in the following order: c) removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C); 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 preferably also according to color and reflectance, and selecting a polypropylene-rich stream of high transparency, thereby generating a sorted polypropylene recycling stream (D).
  • the process comprises steps c) and d) in the following order: d) sorting the separated mixed-plastic recycling stream (B), preferably by means of one or more optical sorters, according to polymer type and transparency, and preferably also according to color and reflectance, and selecting a polypropylene-rich stream of high transparency, thereby generating a non-separated sorted polypropylene recycling stream (D1); c) removing metal particles from the non-separated sorted polypropylene recycling stream (D1) to prepare a sorted polypropylene recycling stream (D).
  • the process comprises the following step e): e) conducting a quality-control (1) step to determine the quality of the sorted polypropylene recycling stream (D), based on the following parameters, wherein the following conditions were pre-determined for these parameters: e1) the content of flexible polyethylene articles is below 5 wt.-%, 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), and being determined by sorting by hand following a visual inspection and/or by optical imaging via near-IR spectroscopic analysis
  • the process comprises the following step j): j) conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I), based on the following parameters, wherein the following conditions were pre-determined for these parameters: 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 j3) the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes is below 5 wt.-%; all contents being relative to the total weight of the light fraction polypropylene recycling stream (I), and being determined by sorting by hand following a visual inspection, on a sample from the light fraction polypropylene recycling stream (I), and allowing the light fraction polypropylene recycling stream (I) to proceed to step k) if the pre-determined conditions for these parameters are fulfilled, thereby generating a quality-controlled (2) polypropylene recycling stream (J1),
  • the process comprises the following step j): j) conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I), based on the following parameters, wherein the following conditions were pre-determined for these parameters: j4) the content of transparent flexible polypropylene flakes is more than 80 % by number, j5) the content of polypropylene is more than 92 wt.-%, and j6) the content of polyethylene is below 6 wt.-%, the content in j4) being relative to the total flake number of the light fraction polypropylene recycling stream (I) and being 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) being relative to the total weight of the light fraction polypropylene recycling stream (I) and being determined, optionally by the use of
  • the process comprises the following step j): j) conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I), based on the following parameters, wherein the following conditions were pre-determined for these parameters: 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.-%, j3) the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes is below 5 wt.-%, j4) the content of transparent flexible polypropylene flakes is more than 80 % by number, j5) the content of polypropylene is more than 92 wt.-%, and j6) the content of polyethylene is below 6 wt.-%, the contents in j1) to j3) being relative to the total weight of the light fraction polypropylene recycling stream (I) and being determined by sorting by hand following a visual inspection; the following conditions were pre
  • the process comprises the following step j): j) conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I), based on the following parameters, wherein the following conditions were pre-determined for these parameters: j4) the content of transparent flexible polypropylene flakes is more than 80 % by number, j5) the content of polypropylene is more than 92 wt.-%, and j6) the content of polyethylene is below 6 wt.-%, the content in j4) being relative to the total flake number of the light fraction polypropylene recycling stream (I) and being 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) being relative to the total weight of the light fraction polypropylene recycling stream (I) all contents being relative on the total weight of the light
  • the process comprises the following steps g) to i): 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); h) drying the washed polypropylene recycling stream (G), thereby obtaining a dried polypropylene recycling stream (H); 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).
  • the process comprises the following steps g) to i): 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); i) separating 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), wherein the polypropylene recycling stream (G) is dried during separation.
  • the process comprises the following steps k) and l): k) melt-extruding and pelletizing the quality-controlled (2) polypropylene recycling stream (J), being stream (J1) and/or (J2), wherein additives (Ad) are added in the melt state, to form an extruded and pelletized polypropylene recycling product (K); and l) aerating, preferably at an air temperature in the range of from 100 to 150 °C, the extruded and pelletized polypropylene recycling product (K) to remove volatile organic compounds, thereby generating an aerated extruded pelletized, polypropylene recycling product (L), and thus providing the mixed-plastic polypropylene recycling blend.
  • the process does not comprise step l) and comprises the following step k): k) melt-extruding and pelletizing the quality-controlled (2) polypropylene recycling stream (J), being stream (J1) and/or (J2), wherein additives (Ad) are added in the melt state, to form an extruded and pelletized polypropylene recycling product (K), and thus providing the mixed-plastic polypropylene recycling blend.
  • the process comprises the following steps: 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); 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; c) removing metal particles from the separated mixed-plastic recycling stream (B) to prepare a purer separated mixed-plastic recycling stream (C); d) sorting the purer separated mixed-plastic recycling stream (C), preferably by means of one or more optical sorters, according to polymer type, transparency, color and reflectance, and selecting a polypropylene-rich stream of high transparency, thereby generating a sorted polypropylene recycling stream (D); e) optionally, conducting a quality-control (1) step to determine the quality of the sorted polypropylene
  • 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.
  • post-consumer waste denotes waste used by consumers such as in private households.
  • the post-consumer waste originates from conventional collecting systems, e.g., as those implemented in the European Union.
  • industrial waste denotes manufacturing scrap, which does not normally reach a consumer.
  • the mixed plastic originates from post-consumer waste.
  • mixed plastic may vary broadly in composition, i.e., it 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-term decomposition 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. Accordingly, as used herein, “mixed-plastic polypropylene recycling blend” denotes a recycling product obtained from mixed plastic and comprising a high content of polypropylene.
  • the mixed-plastic polypropylene recycling blend preferably originates from post-consumer waste.
  • a “blend” denotes a mixture of two or more components, presently polypropylene components. As they preferably originate from post-consumer waste, usually all polymer components of the mixed-plastic polypropylene recycling blend are recycling material, i.e., they are usually not virgin (i.e., not non-recycling) polymer material.
  • 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).
  • Step a) of the process according to the present invention 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).
  • a “precursor mixed-plastic recycling stream (A)” denotes a stream of mixed plastic, as defined above, comprising plastic objects originating from waste, preferably post-consumer waste, i.e., having completed at least a first use cycle (or life cycle) and having already served their first purpose.
  • the precursor mixed-plastic recycling stream (A) comprises at least 70 wt.-%, preferably at least 80 wt.-%, more preferably at least 85 wt.-%, of flexible polymer articles, relative to the total weight of the precursor mixed-plastic recycling stream (A).
  • the precursor mixed-plastic recycling stream (A) comprises only a lower amount (i.e., up to 30 wt.-%) of rigid polymer articles and other components.
  • Assessment of the content of flexible polymer articles may be done on a sample of the precursor mixed-plastic recycling stream (A) via visual evaluation by a skilled person or by using a state of the art ballistic separator for quantifying the two fractions combined with visual inspection.
  • 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.
  • 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 ⁇ m, i.e., they have a thickness of less than 120 ⁇ m, while rigid polymer articles have a thickness of equal to or more than 120 ⁇ m. Based on their structure, flexible polymer articles are also referenced as 2D polymer articles, and rigid polymer articles are referenced as 3D polymer articles. The thickness can be measured on a sample of flexible polymer articles by a micrometer gauge.
  • 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). It is to be understood that “flexible (polymer) articles” denotes the entire articles as well as parts thereof.
  • the precursor mixed-plastic recycling stream (A) contains flexible polypropylene articles.
  • the precursor mixed-plastic recycling stream (A), particularly the flexible polymer articles thereof, may contain a mixture of polyolefins as obtained from the unsorted mixed plastic, or it may have already been enriched in one type of polyolefin, i.e., polypropylene, either by sorting of a mixed-plastic recycling stream or via careful waste collection management.
  • the precursor mixed-plastic recycling stream (A) comprises 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.
  • 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.
  • the precursor mixed-plastic recycling stream (A) is enriched in the content of flexible polypropylene articles.
  • the content of flexible non- polypropylene articles, such as flexible polyethylene articles has been reduced.
  • the content of flexible polypropylene articles may be at least 70 wt.-%, preferably at least 80 wt.-%, more preferably at least 85 wt.- %, relative to the precursor mixed-plastic recycling stream (A).
  • This content can be broadly assessed on a sample of the precursor mixed-plastic recycling stream (A) via visual evaluation by a skilled person, and/or by optical methods, such as near-IR spectroscopic analysis, mid- IR spectroscopic analysis, laser induced break down spectroscopic analysis, laser induced fluorescence spectroscopic analysis, Raman spectroscopic analysis, and Fourier-transform infrared (FTIR) spectroscopic analysis.
  • 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.
  • a precursor mixed-plastic recycling stream (A) may involve the collection of suitable polyolefin-containing materials from a post-consumer (e.g., from kerbside recycling bins) or post-industrial source, or alternatively the mixed-plastic recycling stream (A) can be purchased from any commercial recycling firm.
  • the mixed-plastic recycling stream (A) comprises a high content of flexible polymer articles, as defined above, and may already be enriched in flexible polypropylene articles.
  • 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.
  • Commercial mixed-plastic recycling streams are often obtained in the form of a bale.
  • the precursor mixed-plastic recycling stream (A) is provided in the form of a bale, it will be required to break apart the bale before the precursor mixed-plastic recycling stream (A) undergoes the separating of step b). Depending on which method has been used to pack the bale, it may also be necessary to remove any wires that were used to strap the bale (bale de-wiring) and/or empty the bale from a container, such as a plastic bag or wrapping (bag/bale opening).
  • 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). Debaling via an automatic bale opener is preferred.
  • 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.
  • the person skilled in the art would be aware of multiple ways in which the separating of step b) could be achieved.
  • 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.
  • the separation step b) is conducted as a sieving step, more preferably by using one sieve with a sieve diameter of 30 mm and another sieve with a sieve diameter of 400 mm to divide the precursor mixed recycling stream into three streams: 1) an undersized stream of articles having a longest dimension of less than 30 mm, 2) an oversized stream of articles having a longest dimension of greater than 400 mm and 3) a stream of articles with a longest dimension in the range of from 30 to 400 mm resulting in the separated mixed-plastic recycling stream (B).
  • the undersized and oversized streams may either be discarded or redirected for use in other mechanical polyolefin recycling processes.
  • 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). Some contents of metal particles may already be sorted out based on their sizes in step b) of the process.
  • 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.
  • it is important that metal particles are removed before any size reduction step (such as before the size-reducing step f) and/or the extrusion and pelletizing step k)), in order to protect the blades and/or knives from blunting or breaking.
  • step c) flexible polymer articles comprising magnetic metallic layers may be removed by this step as well.
  • 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.
  • 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. In some embodiments, a step of removing metal particles is carried out for at least a second time in the process before the extrusion step k).
  • a step of removing metal particles is additionally carried out before the size-reducing step f). In some embodiments, a step of removing metal particles is additionally carried out before the melt-extruding step k).
  • 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).
  • sorting step d) enables the preparation of high-quality recycled products, regardless of the quality of the feedstock material.
  • 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)).
  • the sorting does not provide streams of articles having 100 % of the characteristic according to which the sorting is carried out. For example, if it is sorted according to color, the articles do not need to be 100 % colored. 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 (either by article weight or by articles area, as defined below).
  • 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.
  • the term “predominantly” is to be understood to indicate that the articles sorted need not be 100 % of polypropylene, but the amount of polypropylene present in a particular article may be selected according to the purity needs of the products of the process.
  • the sorting would be stricter with regard to the amount of polypropylene, whilst if it is more important to maximize the yield at the expense of a minor drop in purity, then this could also be achieved.
  • the present process focuses on the purity of the product, why higher amounts of polypropylene would be adjusted for the selection.
  • the article sorted comprises at least 75 wt.-%, more preferably at least 85 wt.-%, even more preferably at least 95 wt.-%, and most preferably up to 100 wt.-% of polypropylene.
  • the sorting method according to polymer type is not particularly limited.
  • the sorting according to polymer type of step d) is carried out using one or more optical sorters.
  • optical sorter 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).
  • EM electromagnetic
  • 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.
  • 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.
  • more complex AI-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).
  • 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.
  • “Predominantly” is to be understood as defined above, meaning that the articles to be sorted need not be 100 % transparent, preferably at least 60 % and more preferably at least 75 % of an article area (i.e., the area being one surface of the article) are transparent.
  • Non-transparent articles are, for example, articles having a separate layer of foreign materials and/or containing such high contents of foreign material that one cannot see through the major part of these articles, e.g., at least 75 % of the article area (being one surface of a flexible article) is non-transparent.
  • 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. 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 ⁇ m in thickness).
  • 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 laser spectroscopic analysis. These methods can be used for the sorting according to transparency of step d).
  • the sorting according to transparency of step d) may be carried out using one or more optical sorters, as defined above.
  • the sorting according to polymer type and according to transparency may be carried out in any order or concurrently.
  • the purer separated mixed-plastic recycling stream (C) is first sorted according to polymer type, and then according to transparency.
  • the purer separated mixed-plastic recycling stream (C) is first sorted according to transparency, and then according to polymer type.
  • the purer separated mixed-plastic recycling stream (C) is concurrently sorted according to transparency and according to polymer type.
  • sorting according to polymer type is conducted first.
  • optical sorters as exemplified above are preferably used, and they may be the same for both sorting sub-steps or may be different.
  • a polypropylene-rich stream of high transparency is selected for the further process steps.
  • the sorting step d) may further comprise sorting according to color and/or reflectance. 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.
  • 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 ⁇ m 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.
  • more complex AI-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.
  • step d) comprises sorting the purer separated mixed-plastic recycling stream (C) according to polymer type and transparency.
  • step d) comprises sorting the purer separated mixed-plastic recycling stream (C) according to polymer type, transparency and color. In some embodiments, step d) comprises sorting the purer separated mixed-plastic recycling stream (C) according to polymer type, transparency and reflectance. In some particular embodiments, step d) comprises sorting the purer separated mixed-plastic recycling stream (C) according to polymer type, transparency, color and reflectance. Purity of the final product can generally be improved with the number of sorting sub-steps. However, based on the composition of the feedstock used in the process some sorting sub-steps may not be required. For example, if the feedstock does not contain metallized articles, the sorting according to reflectance may not provide any improvement.
  • 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).
  • the quality of the sorted polypropylene recycling stream (D) is based on the following parameters: e1) the content of flexible polyethylene articles, e2) the content of flexible multi-material multi-layer articles, e3) the content of transparent flexible polypropylene articles, e4) the content of metallized flexible polypropylene articles, e5) the content of colored flexible polypropylene articles, and e6) optionally, the content of flexible polypropylene articles. 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.
  • these pre-determined conditions are: e1) the content of flexible polyethylene articles is below 5 wt.-%, 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).
  • Parameters e1) to e6) are evaluated based on the following features:
  • the wording “flexible polyethylene articles” of parameter e1) refers to flexible articles comprising at least 75 wt.-% of polyethylene.
  • 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.
  • transparent flexible polypropylene articles 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 ⁇ m 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.
  • 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).
  • 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.
  • the metal components may be in the form of metal layers or metal inks on the flexible polypropylene articles.
  • colored flexible polypropylene articles 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.
  • the wording “flexible polypropylene articles” of parameter e6) refers to flexible articles comprising at least 75 wt.-% of polypropylene.
  • the quality of the sorted polypropylene recycling stream (D) in step e) 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).
  • 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 camera systems in combination with either simple recognition algorithms or more complex AI-based systems, with the latter expected to predominate, as AI recognition improves yet further.
  • a sample from the sorted polypropylene recycling stream (D) usually 20 to 50 kg of material, are drawn and analyzed. Generally, larger amounts of sample material enable a more accurate determination of the content of the sorted polypropylene recycling stream (D).
  • the analysis is typically performed on one sample and optionally repeated on more further samples.
  • 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).
  • 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 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).
  • 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.
  • 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. It is preferable that the polypropylene recycling stream (X) exceeds the pre-determined conditions by at least 10 %, more preferably at least 20 %, even more preferably at least 30 %, such as at least 50 % or more.
  • the content of polyethylene articles in the polypropylene recycling stream (X) is below 4.5 wt.-% or less (i.e., 5 wt.-% minus 10 %).
  • the content of transparent flexible polypropylene articles in the polypropylene recycling stream (X) is at least more than 38.5 wt.-% (i.e., 35 wt.-% plus 10 %). 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).
  • 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 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).
  • the size-reducing step f) is a wet-grinding step. 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 mm 2 , more preferably from 100 to 1600 mm 2 and most preferably from 150 to 900 mm 2 .
  • 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 mm 2 .
  • the size-reducing step f) may be a wet process or a dry process.
  • the size-reducing step f) is a wet process, e.g., carried out in the presence of water or an aqueous solution, wherein the quality-controlled (1) polypropylene recycling stream (E) or the sorted polypropylene recycling stream (D) is first contacted with water or an aqueous solution (W0) and the obtained suspension is subjected to size-reducing .
  • the choice of aqueous solution (W0) is not particularly limited; however, it is preferred that the aqueous solution (W0) 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.
  • the aqueous solution (W0) is at least part of the recycled aqueous washing solution removed during step g). If the size-reducing step f) is a wet process, then the flaked polyolefin recycling stream (F) obtained therefrom may be mechanically dried before step g) begins. 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.
  • the recycling of the aqueous washing solution used in step g) allows for improved process economy, wherein only one aqueous washing solution need be provided for use in the entire process.
  • the aqueous washing solution used in step g) is preferably an alkaline solution, assisting with the removal of foreign materials in step f) and step g). If more than one washing sub-step is used, it is important that the cleanest washing solution (i.e., with the least foreign material present) is used in the last washing sub-step, to ensure that the resultant washed polyolefin stream is as clean as possible. Finally, the multiple use of a single aqueous washing solution enables simplified waste stream treatment, avoiding the need for the treatment of multiple different waste streams containing different chemicals.
  • 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).
  • the wording “rinsing with water” indicates the addition of water, which is used to remove foreign material or remaining liquid from the surface of the polypropylene material (i.e., in the flaked polypropylene recycling stream (F)).
  • 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).
  • 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.
  • 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.
  • inks and/or ink-derived contaminants in the final recyclate grade does usually not unduly affect the polymer properties, such as rheological or mechanical properties, it does have a significant influence on the appearance of the recyclate, typically contributing to a dark grey or black color. For some applications, a dark grey or black is an appropriate color. However, it is intended by the present process to provide a very pure unpigmented recyclate.
  • the final recyclate grade can be improved by efficient sorting and/or washing to reduce the content of ink and ink-derived contaminants, such as various metal ions and other organic compounds that may contribute to unpleasant odors (the inks (or binders) themselves are highly unlikely to be odorous in nature, but degradation of the inks (or binders) during compounding may generate volatile odorous compounds) or otherwise contribute to deleterious effects in the final recyclate grade (e.g., metal ions catalyzing degradation pathways).
  • the washing is continued until at least 90%, more preferably at least 95%, most preferably essentially 100% of all ink has been removed from the flaked polypropylene recycling stream (F).
  • the extent of ink removal may be monitored throughout the one or more washing steps to ensure that enough ink has been removed. Additionally or alternatively, it is within the routine of the skilled person to suitably optimize the washing conditions in order to achieve this degree of ink removal, with key parameters such as washing temperature, washing duration, choice of washing solution, presence/absence of agitation, affecting the ink removal of washing steps known in the art.
  • suitable conditions for the removal of inks during polyolefin recycling have been disclosed in WO 2021/018605 A1 and WO 2021/104797 A1. In these documents, either acid washes (preferably conc. H 2 SO 4 ) or acid/oil emulsions (preferably conc.
  • 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.
  • 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.
  • 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.
  • the aqueous washing solution is an aqueous solution of sodium hydroxide.
  • 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.
  • the aqueous washing solution is a sodium hydroxide solution having a sodium hydroxide concentration in the range 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.
  • Aqueous washing solutions suitable for use in the washing sub-step(s) of step g) may comprise a detergent to base (preferably, NaOH) ratio in the range of from 0.01:1 to 1:1, preferably from 0.05:1 to 0.5:1.
  • 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. 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.
  • 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.
  • 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.
  • 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
  • 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): 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); 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 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).
  • step g) comprises, in the given order, the following sub-steps: g1a) 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 (G1a); g2a) removing the aqueous washing solution and optionally any material not floating on the surface of the aqueous washing solution, thereby generating a first washed polypropylene recycling stream (G2a); g1b) washing the first washed polypropylene recycling stream (G2a) with an aqueous washing solution at a controlled temperature for a controlled duration, thereby generating a second suspended polypropylene recycling stream (G1b); g2b) removing the aqueous washing solution and any optionally material not floating on the surface of the aqueous washing solution, thereby generating
  • Step g) can be conducted with more than two washing sub-steps. If conducted with more than two washing sub-step, e.g., with three, four etc., washing sub-steps, it is particularly preferred that step g) comprises additional sub-steps g1) and g2) between sub-steps g2b) and g3), such as sub-steps g1c) and g2c), and optionally also g1d) and g2d), etc.
  • the condition in all the washing sub-steps may be same or different.
  • the temperature is lower than in the second and further washing sub-steps.
  • inks and other contaminants such as adhesives and/or paper labels
  • 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. 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/cm 3 .
  • 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 l) 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.
  • the removed aqueous washing solution may be recycled to another washing sub-step, generally a preceding washing sub-step (e.g., an aqueous washing solution from a second washing/removal sub-step may be used as a first aqueous washing solution in a continuous process).
  • a preceding washing sub-step e.g., an aqueous washing solution from a second washing/removal sub-step may be used as a first aqueous washing solution in a continuous process.
  • Removed aqueous washing solution containing foreign material residues may be treated, for example filtered, to remove these residues before the aqueous washing solution may be used again for another washing sub-step.
  • 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.
  • step g) is carried out with the following sub-steps: 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); g1b) 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 (
  • washing sub-step g1a) is carried out with a first aqueous washing solution (W1) without the input of thermal energy. 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 than 50 °C, such as less than 40 °C.
  • 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.
  • the first aqueous washing solution (W1) 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).
  • the detergent may be selected from any of the detergents described above. It is further preferred that the first aqueous washing solution (W1) is at least part of the recycled aqueous washing solution removed during sub-step g2b).
  • Sub-step g1a) is preferably carried out during agitation, particularly through ultrasonic treatment, and for a duration of 5 to 120 min.
  • removal sub-step g2a) does not involve the targeted removal of foreign material through the use of, for example, a so-called float/sink separation, as described above.
  • an optional rinsing sub-step (g3a)) with water may be carried out.
  • Washing sub-step g1b) is carried out with a second aqueous washing solution (W2), wherein sufficient thermal energy is introduced to provide 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 sub-step g1b).
  • the second aqueous washing solution (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 second aqueous washing solution (W2).
  • the detergent may be selected from any of the detergents described above.
  • Sub-step g1b) is preferably carried out during agitation, particularly through ultrasonic treatment, and for a duration of 5 to 120 min.
  • removal sub-step g2b) involves removing any material not floating on the surface of the second aqueous washing solution (W2) by a float/sink separation.
  • a float/sink separation step directly after the high temperature washing sub-step g1b) is extremely beneficial for removing as much foreign material as possible. It is particularly preferred that the aqueous washing solution removed during step g2b) is recycled for use as the first aqueous washing solution (W1) and the aqueous solution (W0), if present, as previously discussed. Following the removal of the second aqueous washing solution (W2), a rinsing sub-step g3) is carried out, under the conditions generally described for rinsing sub-steps.
  • 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. 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.
  • 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).
  • 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. Due to the nature of the precursor mixed-plastic recycling stream (A) in step a), which comprises at least 70 wt.-% of flexible polymer articles, the content of flakes derived from rigid articles will be relatively low.
  • the sorting step d) will further reduce the content of rigid particles in the stream.
  • 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.
  • 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 but rather by a combination of physical properties such as shape and density, especially the ratio surface area to volume.
  • the light fraction polypropylene recycling stream (I) predominantly contains flakes of flexible polypropylene articles, i.e., of 2D articles, while the heavy fraction recycling stream predominantly contains flakes of rigid articles, i.e., of 3D articles.
  • the review article by Alade and Bada (Wind-Sifting Separation: A Review, Jimmy Alade and Samson Oluwaseyi Bada. ACS Omega 20238 (38), 34196-34205, DOI: 10.1021/acsomega.3c01087) in detail describes the separation of articles via wind sifting.
  • a wind sifter which is the preferred device for the separation into a light fraction polypropylene recycling stream (I) and a heavy fraction recycling stream
  • the separation of the 2D and 3D article flakes is done by means of air separation.
  • individual flakes can be separated in an air stream on the basis of their ratio of inertia and/or gravity to the flow resistance.
  • the light fraction polypropylene recycling stream (I) in particular flat flakes follow the air flow, whereas coarse flakes follow the mass force.
  • a light fraction polypropylene recycling stream (I) such as films or 2D article flakes, are separated from a heavy fraction recycling stream, such as hard plastics or 3D article flakes.
  • flakes that are not derived from flexible articles may be removed via sorting operations other than dry-state density separation techniques. Suitable methods include the use of optical sorters that sort by article form, such as camera systems (operating in the visible range of the EM-spectrum). The sorting of such a step can be achieved through simple sorting algorithms, wherein the optical sensor(s) are programmed to assess which flakes should be selected or rejected based on simple binary considerations. Alternatively, more complex AI-based systems can be used to achieve a more precise sorting, in particular when sorting according to article form.
  • article form denotes the shape and form of articles or parts thereof (e.g., flakes of these articles).
  • Commercial optical sorters such as Tomra Autosort, RTT Steinert Unisort and Redwave Pellenc, are able to separate rigid articles from 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 streams of rigid articles and flexible articles.
  • non-polypropylene materials may be removed from the light fraction polypropylene recycling stream (I) via a float/sink separation step that sorts according to density.
  • Step i) of the process involves conducting a quality-control (2) step to determine the quality of the light fraction polypropylene recycling stream (I).
  • the quality-control (2) step serves to determine the efficiency of the proceeding process steps on the quality of the light fraction polypropylene recycling stream (I).
  • the quality of the light fraction polypropylene recycling stream (I) is based on the following parameters: all of parameters j1) to j3): 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 all of parameters j4) to j6): j4) the content of transparent flexible polypropylene flakes, j5) the content of polypropylene, and j6) the content of polyethylene.
  • the light fraction polypropylene recycling stream (I) is allowed to proceed to step k) only if pre- determined conditions for these parameters are fulfilled.
  • these pre-determined conditions are: all of conditions j1) to j3): 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 j3) the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes is below 5 wt.-%; and/or all of conditions j4) to j6): j4) the content of transparent flexible polypropylene flakes is more than 80 % by number, j5) the content of polypropylene is more than 92 wt.-%, and j6) the content of polyethylene is below 6 wt.-%, 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).
  • Parameters j1) to j6) are evaluated based on the following features:
  • 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 ISO 14782:2021, and based on a cast film of 50 ⁇ m 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.
  • 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).
  • colored and non-transparent flexible polyethylene flakes 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 ISO 14782:2021, and based on a cast film of 50 ⁇ m 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.
  • flexible flakes wherein between 25 and 90 % of the area of the flake are transparent, are referred to as partly colored flakes.
  • at least 75 % of the area of the 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.
  • 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).
  • parameters j4) 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.
  • the wording “transparent flexible polypropylene flakes” of parameter j4) is referred to the same articles as described for parameter j1) above.
  • the content is given in % by number of the flakes.
  • parameters j5) and j6) are determined by spectroscopic methods, wherein the total content of polypropylene or polyethylene, respectively, in the sample is obtained.
  • 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).
  • a visual inspection for the sorting by hand following a visual inspection, as a sample from the light fraction polypropylene recycling stream (I), usually 20 to 200 g of material are drawn and analyzed. Generally, larger amounts of sample material enable a more accurate determination of the content of the light fraction polypropylene recycling stream (I). The analysis is typically performed on one sample and optionally repeated on more further samples.
  • 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).
  • FTIR Fourier-transform infrared
  • 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).
  • FTIR Fourier-transform infrared
  • a flake analyzer device may combine two or more of the detections methods: near-IR spectroscopic analysis, near-IR/VIS spectroscopic analysis and/or a camera system operating in the visible range of the EM-spectrum.
  • near-IR spectroscopic analysis near-IR/VIS spectroscopic analysis and/or a camera system operating in the visible range of the EM-spectrum.
  • the optical imaging several grams (e.g., 5-500 g) of the light fraction polypropylene recycling stream (I) may be used as the sample.
  • 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.
  • 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.
  • 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. It is preferable that the polypropylene recycling stream (Y) exceeds the pre-determined conditions by at least 10 %, more preferably at least 20 %, even more preferably at least 30 %, such as at least 50 % or more.
  • the content of materials other than flexible polypropylene flakes or flexible polyethylene flakes in the polypropylene recycling stream (Y) is below 4.5 wt.-% or less (i.e., 5 wt.-% minus 10 %).
  • the content of transparent flexible polypropylene flakes in the polypropylene recycling stream (Y) is at least more than 88 wt.-% (i.e., 80 wt.-% plus 10 %). In this way, the quality of the light fraction polypropylene recycling stream (I) is improved.
  • 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.
  • at least one metal preferably selected from titanium (Ti), calcium (Ca) and aluminum (Al
  • step j) the light fraction polypropylene recycling stream (I) is allowed to proceed to step k) as a quality-controlled (2) polypropylene recycling stream (J1) or (J2); if the sum of contents of titanium (Ti), calcium (Ca) and aluminum (Al) is below 3,000 ppm, relative to the total weight of the light fraction polypropylene recycling stream (I) and determined by X-ray fluorescence (XRF) spectroscopy. In this way, the quality of the light fraction polypropylene recycling stream (I) may be further improved.
  • XRF X-ray fluorescence
  • 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 ⁇ m), and improves the quality of the resultant recyclate.
  • 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.
  • 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.
  • the second filter may have a mesh size of 40 to 130 ⁇ m, preferably 45 to 110 ⁇ m, more preferably 50 to 100 ⁇ m.
  • the second filter may have a mesh size smaller than that of the first filter.
  • a cascade of filters may be used. For example, a cascade of more than two filters is used. In some examples, three, four or five filters are used in a cascade. 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.
  • perforations in the first filter may be formed by laser (laser filter). The first filter may have perforations that are not uniform in cross-section.
  • step k) comprises a first filtration sub-step k1), a vacuum degassing sub-step k2) and a second filtration sub-step k3).
  • 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).
  • 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.
  • additives (Ad) are added during step k), preferably in the melt state.
  • These additives may be 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.
  • Step l) 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 l) is an optional step of the process.
  • the aeration step l) may be generally carried out using air, inert gases and/or steam.
  • the aeration step l) is carried out by contacting the extruded, and preferably pelletized, polypropylene recycling product (K) with a gas being at least 60 % by volume N 2 gas.
  • the temperature at which the aeration according to step l) takes place may be in the range of from 50 to 155 °C, preferably from 100 to 150 °C. It may also be beneficial to conduct the aeration step l) at a reduced pressure, for example at less than 500 mbar, more preferably less than 200 mbar and most preferably less than 100 mbar.
  • the aeration step l) 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.
  • 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.
  • Mixed-plastic polypropylene recycling blend The present invention is also directed to a mixed-plastic polypropylene recycling blend obtained or obtainable by the process according to the present invention in any of the above embodiments.
  • the mixed-plastic polypropylene recycling blend has a polypropylene content of at least 92 wt.-%, more 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 100 wt.-%, preferably from 93 to 99.5 wt.-%, such as from 93 to 99 wt.-%.
  • compositions such as the mixed-plastic polypropylene recycling blend
  • 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). If not indicated otherwise, “%” denotes weight percent.
  • the mixed-plastic polypropylene recycling blend 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.
  • 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).
  • the mixed-plastic polypropylene recycling blend may contain one or more of the following: 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.
  • the mixed-plastic polypropylene recycling blend is of high purity and contains only a very small content of contaminants.
  • 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.-%, more preferably less than 0.9 wt.-%, and even 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.- %.
  • the mixed-plastic polypropylene recycling blend has a content of inclusions of a density of at least 1.1 g/cm 3 of 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”).
  • the content of inclusions of a density of at least 1.1 g/cm 3 and equal to or lower than 1.53 g/cm 3 is preferably in the range of from 0.01 to less than 0.40 vol.-%, more preferably from 0.01 to 0.35 vol.-%, (i.e., denoted as “low density inclusions”).
  • 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. 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/cm 3 (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.
  • 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.
  • 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/cm 3 and equal to or lower than 1.53 g/cm 3 are considered to be organic contaminants, such as non-polyolefin polymers.
  • organic contaminants may comprise, or consist essentially of, polyamide and polyethylene terephthalate (PET).
  • the mixed-plastic polypropylene recycling blend of the present invention has low contents of these residual contaminants.
  • the mixed-plastic polypropylene recycling blend has a content of inclusions of a density of at least 1.1 g/cm 3 having inclusion sizes of more than 50 ⁇ m in diameter of less than 0.25 vol.-%, preferably less than 0.20 vol.-%, and/or inclusion sizes of more than 100 ⁇ m 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.
  • X-ray CT X-ray Computed Tomography
  • 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: 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; 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; 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; 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; e)
  • Al aluminum
  • the mixed-plastic polypropylene recycling blend is characterized by good rheological properties.
  • the mixed-plastic polypropylene recycling blend has a melt flow rate MFR 2 in the range of from 3 to 10 g/10 min, preferably from 4 to 9 g/10 min, such as from 5 to 8 g/10 min, determined according to ISO 1133, 230 °C, 2.16 kg.
  • the mixed-plastic polypropylene recycling blend has a content of soluble fraction (SF) in the range of from 3.0 to 12.0 wt.-%, more preferably from 3.5 to 11.0 wt.-%, even 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.
  • the soluble fraction (SF) has an intrinsic viscosity (IV(SF)) of below 1.1 dl/g, more 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.
  • the mixed-plastic polypropylene recycling blend may further have at least one, preferably all, of the following properties, determined by CRYSTEX QC analysis as described herein below: 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; 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 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
  • the mixed-plastic polypropylene recycling blend has very advantageous mechanical properties.
  • the mixed-plastic polypropylene recycling blend has a flexural modulus in the range of from 1050 to 1350 MPa, preferably from 1070 to 1300 MPa, determined according to ISO 178 (method A, type B specimen).
  • the mixed-plastic polypropylene recycling blend may further have at least one, preferably all, of the following properties, determined as described herein below: a) an Eta(0.05rad/s), 200°C in the range of from 3000 to 4500 Pa.s, b) an Eta(300rad/s), 200°C in the range of from 250 to 350 Pa.s, and c) a Shear Thinning Factor (STF), Eta(0.05)/Eta(300), in the range of from 9.5 to 16.0.
  • the mixed-plastic polypropylene recycling blend is preferably an extruded, such as melt- extruded, material.
  • the melt-extruded mixed-plastic polypropylene recycling blend is present in the form of pellets.
  • the mixed-plastic polypropylene recycling blend may comprise additives (Ad), e.g., as described herein above.
  • Ad additives
  • Figures The present invention is further illustrated by the following figures, showing: Fig.1: a precursor mixed-plastic recycling stream (A) of Inventive Example IE1; Fig.2: a sample of the sorted polypropylene recycling stream (D) of Inventive Example IE1; and Fig.3: a sample of the light fraction polypropylene recycling stream (I) of Inventive Example IE2 after sorting by hand.
  • the sorted fractions are: A: transparent flexible PP, B: colored flexible PP, C: white flexible PP, D: partly-colored flexible PP, E: flexible PE, F: other materials (fibers, foams, etc.).
  • D partly-colored flexible PP
  • E flexible PE
  • F other materials (fibers, foams, etc.).
  • each plate was measured before any FTIR measurements were performed; all plates were between 100 to 200 ⁇ m thick. To control the plate surface and to avoid any interference during the measurement, all plates were pressed between two double-sided silicone release papers. 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.
  • Spectrometer Standard transmission FTIR spectroscope such as Bruker Vertex 70 FTIR spectrometer was used with the following set-up: o a spectral range of 4000-400 cm -1 , o an aperture of 6 mm, o a spectral resolution of 2 cm -1 , o with 16 background scans, 16 spectrum scans, o an interferogram zero filling factor of 32 o Norton Beer strong anodization. Spectra were recorded and analyzed in Bruker Opus software.
  • Calibration samples As FTIR is a secondary method, several calibration standards were compounded to cover the targeted analysis range, typically from: o 0.2 wt% to 2.5 wt% for PA o 0.1 wt% to 5 wt% for PS o 0.2 wt% to 2.5 wt% for PET o 0.1 wt% to 4 wt% for PVC
  • Borealis HC600TF as iPP
  • Borealis FB3450 as HDPE
  • 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).
  • the content of inorganic elements was determined by X-ray fluorescence (XRF).
  • XRF X-ray fluorescence
  • 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: range Element (ppm) Al 0 - 53.3 Si 0 - 1970 P 0 - 103 S 0 - 281 Ca 0 - 583 Ti 0 - 273 Zn 0 - 576
  • the analysis are done under vacuum on a plaque with a diameter of 40mm and a thickness of 2mm.
  • 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.
  • the content of each precise element was evaluated with the following standards: Elements Range (ppm) Standard used LOD (ppm) Al 0 - 53.3 Custom 2.5 Ca 0 - 583 Custom 2.8 Fe - P 0 - 103 Custom 1.3 S 0 - 281 Custom 2.1 Si 0 - 1970 Custom 14.4 Ti 0 - 273 Custom 1.5 Zn 0 - 576 Custom 0.7 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).
  • Micro capillaries (10 pL) were used to add diluted limonene standards of known concentrations to the sample. Addition of 0, 2, 20 and 100 ng equals 0 mg/kg, 0.1 mg/kg, 1 mg/kg and 5 mg/kg limonene, in addition standard amounts of 6.6 mg/kg, 11 mg/kg and 16.5 mg/kg limonene were used in combination with some of the samples tested in this application. For quantification, ion 93 acquired in SIM mode was used. Enrichment of the volatile fraction was carried out by headspace solid phase micro- extraction with a 2 cm stable flex 50/30 pm DVB/Carboxen/PDMS fibre at 60 °C for 20 minutes.
  • ion 60 acquired in SIM mode was used for all acids except propanoic acid, here ion 74 was used.
  • Pellets were scanned as delivered and placed in a cylindrical sample holder.
  • the Voxelsize was set to 4 ⁇ m.
  • 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.
  • 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.
  • discs with 5 mm in diameter and 500 ⁇ m 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.
  • the software Avizo for industrial inspection 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. 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/cm3 and that of PET with 1.38 g/cm3 into account, this threshold corresponds to a density of 1.53 g/cm3. A second analysis was performed with a lower threshold leading to the fraction of low density particulate contaminants.
  • 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.
  • 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.
  • 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). 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 molding was carried out according to ISO 19069-2.
  • 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-capillary viscometer is used.
  • IR4 detector is a multiple wavelength detector measuring IR absorbance at two different bands (CH 3 stretching 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 by 13 C- NMR) and each at various concentrations, in the range of 2 and 13 mg/ml.
  • IV (dL/g) a* Vsp/c
  • the polymer solution is blanketed with the N 2 atmosphere during dissolution.
  • 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.
  • the measurements were performed on an Anton Paar 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.
  • 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.
  • Eta (x rad/s) is determined according with equation 10.
  • the ETA(300 rad/s) is defined by the value of the complex viscosity, determined at a frequency sweep of 300 rad/s.
  • 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.
  • 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.
  • the content of flexible polymer articles in the feedstocks of IE1 was 81.4 wt.-% (with a PP:PE ratio of 23.8:1) and of IE2 was 71.1 wt.-% (with a PP:PE ratio of 0.3:1).
  • 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; e) quality control step (1) for IE1 (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) – performed with different methods (e.g., via hand sorting and flake analyzer), 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
  • CE1 and CE2 were prepared by the mechanical polyolefin recycling process according to WO 2023/209075 A1 comprising a quality-control step based on the analysis of the ethylene- propylene rubber (EPR) fraction of the soluble fraction.
  • EPR ethylene- propylene rubber
  • CE2 German post-consumer plastic trash fulfilling the specification DSD323-2 was used as precursor mixed-plastic recycling stream (A).
  • the post-consumer plastic trash fulfilling the German specification DSD323-2 was used as precursor mixed-plastic recycling stream (A) and prepared as described in WO 2023/209075 A1, however, without the quality-control step based on the EPR content.
  • CE1 to CE3 were prepared by an analogous recycling process – however either without any quality control step (CE3) or with a quality control step based on the EPR content (CE1 and CE2).
  • Quality control steps The results of the quality control steps for the Inventive Examples IE1 and IE2 are summarized in Table 2 below: Table 2: Results of the quality control steps.
  • Composition (wt.-%) IE2 IE1 Quality control step (1) via hand sorting PP flexibles 82 Transparent PP flexibles 40 Partly-colored PP flexibles No quality control (1) 30 Colored PP flexibles 7 Metallized PP flexibles 5 PE flexibles 3 Organic materials (PS, P VC, PET, etc.) 10 Paper - MMML flexibles 4 Rest 3 Quality control step (2) via hand sorting PP flexibles 94 96 Transparent PP flexibles 84 87 Colored and partly- c olored PP flexibles 8 7 White PP flexibles 2 2 Fibers 3 1.5 PE flexibles (colored/non- 1.3 1.5 transparent) Rigids (PO) and other polymers (PS, PVC, 1.4 1 PET, PU, foams etc.) Paper - - Metallized PP flexibles - - Rest 0.3 - Quality control step (2) PP (IR) 94 94.2 Transparent PP f lexibles* (flake analyzer) n.m.
  • the number-% of transparent flexible PP flakes in Inventive Example IE1 was determined with a flake analyzer under the following conditions: 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.
  • 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.
  • 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 were individually analyzed by the flake analyzer, resulting in a total number of flakes and a number of transparent flexible PP flakes.
  • Table 3 Results of the analysis by flake analyzer. Flake Analyzer Composition n (number) % by number PP transparent 5516 88.80 Total 6212 100.00 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.
  • Table 6 Inclusions in the polymer blend. Inclusions (X-ray CT, vol.-%) CE1 IE1 IE2 High density (total) 0.09 0.05 0.08 High density >50 ⁇ m 0.05 0.02 0.04 High density >100 ⁇ m 0.03 0.01 0.02 Low density (total) 0.40 0.18 0.26 Low density >50 ⁇ m 0.24 0.08 0.12 Low density >100 ⁇ m v% 0.13 0.04 0.07 High + low density (total) 0.48 0.23 0.34 High + Low density >50 ⁇ m 0.29 0.10 0.16 High + Low density >100 ⁇ m 0.15 0.05 0.09 According to Table 6, the inclusions observed in the polymer blends by X-ray CT were reduced in both Inventive Examples versus the Comparative Example CE1.

Landscapes

  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)

Abstract

La présente invention se rapporte à un procédé de fourniture d'un mélange de recyclage de polypropylène et plastique mixte caractérisé par une pureté élevée et des propriétés physiques bénéfiques. Le procédé est caractérisé par au moins une étape de contrôle qualité pour la détermination de la qualité du flux de recyclage de polypropylène avant l'extrusion. La présente invention se rapporte également à un mélange de recyclage de polypropylène et plastique mixte obtenu ou pouvant l'être par le procédé de la présente invention.
PCT/EP2025/061523 2024-04-29 2025-04-28 Procédé de fourniture d'un mélange de recyclage de polypropylène et plastique mixte de haute pureté Pending WO2025228884A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP24173147.0 2024-04-29
EP24173147 2024-04-29

Publications (1)

Publication Number Publication Date
WO2025228884A1 true WO2025228884A1 (fr) 2025-11-06

Family

ID=90924428

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2025/061523 Pending WO2025228884A1 (fr) 2024-04-29 2025-04-28 Procédé de fourniture d'un mélange de recyclage de polypropylène et plastique mixte de haute pureté

Country Status (1)

Country Link
WO (1) WO2025228884A1 (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7799835B2 (en) * 2003-03-13 2010-09-21 Next-Tec, Ltd. Recycling and reduction of plastics and non-plastics material
WO2021018605A1 (fr) 2019-07-26 2021-02-04 Borealis Ag Procédé d'élimination d'encre ou d'autres matières étrangères de la surface d'un article
WO2021104797A1 (fr) 2019-11-29 2021-06-03 Borealis Ag Procédé d'élimination de matières étrangères de la surface d'un article
WO2023118421A1 (fr) 2021-12-22 2023-06-29 Borealis Ag Procédé de recyclage mécanique de polyoléfines
WO2023139157A1 (fr) * 2022-01-21 2023-07-27 Borealis Ag Analyse et optimisation intégrées d'un procédé de recyclage de polyoléfine mécanique
WO2023180222A1 (fr) 2022-03-22 2023-09-28 Borealis Ag Procédé mécanique de recyclage de polyoléfines
EP4269498A1 (fr) * 2022-04-29 2023-11-01 Borealis AG Mélange de polypropylène mixte-plastique flexible (pp-flex)

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7799835B2 (en) * 2003-03-13 2010-09-21 Next-Tec, Ltd. Recycling and reduction of plastics and non-plastics material
WO2021018605A1 (fr) 2019-07-26 2021-02-04 Borealis Ag Procédé d'élimination d'encre ou d'autres matières étrangères de la surface d'un article
WO2021104797A1 (fr) 2019-11-29 2021-06-03 Borealis Ag Procédé d'élimination de matières étrangères de la surface d'un article
WO2023118421A1 (fr) 2021-12-22 2023-06-29 Borealis Ag Procédé de recyclage mécanique de polyoléfines
WO2023139157A1 (fr) * 2022-01-21 2023-07-27 Borealis Ag Analyse et optimisation intégrées d'un procédé de recyclage de polyoléfine mécanique
WO2023180222A1 (fr) 2022-03-22 2023-09-28 Borealis Ag Procédé mécanique de recyclage de polyoléfines
EP4269498A1 (fr) * 2022-04-29 2023-11-01 Borealis AG Mélange de polypropylène mixte-plastique flexible (pp-flex)
WO2023209075A1 (fr) 2022-04-29 2023-11-02 Borealis Ag Mélange de polypropylène mixte souple-plastique (pp-flex)

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
"Wind-Sifting Separation: A Review, Jimmy Alade and Samson Oluwaseyi Bada.", ACS OMEGA, vol. 8, no. 38, 2023, pages 34196 - 34205
HEINO, E.LLEHTINEN, A.TANNER J.SEPPÄLÄ, J.NESTE OYPORVOO, FINLAND, THEOR. APPL. RHEOL., PROC. INT. CONGR. RHEOL, vol. 1, 1992, pages 360 - 362
PURE & APPL. CHEM, vol. 70, no. 3, 1998, pages 701 - 754
RECYCLASS: "RECYCLABILITY EVALUATION PROTOCOL FOR PP CONTAINERS STANDARD LABORATORY PRACTICE RECYCLABILITY EVALUATION PROTOCOL FOR PP CONTAINERS CONTENT", 30 June 2020 (2020-06-30), XP093044186, Retrieved from the Internet <URL:https://recyclass.eu/wp-content/uploads/2022/02/RecyClass-Recyclability-Evaluation-Protocol-for-PP-containers-v.3.0-FINAL.pdf> [retrieved on 20230504] *

Similar Documents

Publication Publication Date Title
US20250065539A1 (en) A mechanical polyolefin recycling process
EP4269498B1 (fr) Mélange de polypropylène mixte-plastique flexible (pp-flex)
US20250187245A1 (en) A mechanical polyolefin recycling process
EP4496689A1 (fr) Composition de polyéthylène coloré recyclé post-consommation, sa méthode de préparation et articles fabriqués à partir de celle-ci
WO2025228884A1 (fr) Procédé de fourniture d&#39;un mélange de recyclage de polypropylène et plastique mixte de haute pureté
EP4653490A1 (fr) Films coulés présentant des propriétés mécaniques améliorées, fabriqués à partir d&#39;une composition de polypropylène comprenant un mélange de recyclage de polypropylène plastique mixte
WO2025228883A1 (fr) Mélange de recyclage de polypropylène en plastique mixte de haute pureté
WO2025242861A1 (fr) Films coulés à propriétés optiques améliorées à base d&#39;une composition de polypropylène comportant un mélange de plastiques recyclés à base de polypropylène
TW202502512A (zh) 包括消費後回收的聚丙烯樹脂的聚合物組成物、其用途、以及包含該聚合物組成物的物品
Kuhn et al. Increasing the PP-recyclate quality by enhanced mechanical processing of post-consumer packaging waste
WO2025068267A1 (fr) Procédé de recyclage de polypropylène mécanique
EP4624526A1 (fr) Films coulés contenant du recyclat
US20250170761A1 (en) Post-consumer recyclated colored polypropylene composition
WO2025168816A1 (fr) Compositions de polypropylène recyclée
WO2025228882A1 (fr) Procédé de purification d&#39;articles polymères flexibles réutilisés
TW202502511A (zh) 製備包括消費後回收的聚丙烯樹脂的聚合物組成物的方法
WO2025253258A1 (fr) Système et procédé de production de matières recyclées de qualité alimentaire à base de polyoléfine
TW202502510A (zh) 包括消費後回收的聚丙烯樹脂的聚合物組成物、其用途、以及包含該聚合物組成物的物品
TW202502513A (zh) 包括消費後回收的聚丙烯樹脂的聚合物組成物、其用途、以及包含該聚合物組成物的物品

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 25721906

Country of ref document: EP

Kind code of ref document: A1