Patent Application
20250043097
The current invention relates to a method for recycling plastic products, or materials, by depolymerisation. In particular, the current invention provides a method for recycling plastic products comprising, or consisting of, polyethylene terephthalate (PET).
The global demand for polymers (plastics) surpassed 275 million tonnes in 2019, with consumers using a mean of 50 products a day that depend on plastics for their functionality. Whilst the plastic industry is thriving, plastic pollution is causing global issues. Currently, 98% of all plastic waste produced is non-biodegradable. A direct consequence of the disposal of this non-biodegradable plastic is the slow release of microplastics and synthetic fibres into the environment (Mar. Pollut. Bull., 2015, 93, 202).
Polyethylene terephthalate (PET) is a ubiquitous plastic commonly used in food packaging and ‘fast fashion’ clothing. Unfortunately, a significant amount of waste PET is disposed of by either burying in landfill sites or incineration. Many global brands are now working towards producing 100% recyclable or compostable packaging by 2030. Recycled plastic materials are increasingly seen as a way to improve resource efficiency and the sustainable development of packaging. Europe is the second largest regional market for plastic recycling, accounting for almost a quarter of the global recyclate production and consumption in 2019. Mechanical recycling is the most widely used approach for treating plastic waste, such as polyethylene terephthalate (PET) but is considered only a temporary solution, as after each cycle the economic value of the plastic is reduced (downcycling) due to the loss of the properties of the polymer relative to the virgin material.
Chemical recycling, although not currently widely used, has the potential to be able to recycle “mixed” plastic waste and more difficult to recycle packaging (Nature Rev Chem., 2017, 1, 0046). Chemical recycling could solve the problem of downcycling by retaining the value of the monomers in plastics such as PET. However, current methods of chemical recycling, such as the widely studies glycolysis of PET, are often energy intensive and employ homogeneous catalysts that are difficult to recover and recycle, reducing chemical recycling as an economic and environmental viability process. Consequently, current chemically technologies for recycling PET cannot compete in price with virgin PET.
EP3377569 discloses a method of chemical recycling of PET using microwave as an energy source for the depolymerisation of PET. This process uses a homogeneous catalyst and diethylene glycol as a solvent. The homogeneous catalyst is difficult to recover and reuse.
EP2736968 discloses a method and apparatus for the recycling of polymeric materials via a microwave depolymerisation process. The process described is a continuous process for the depolymerisation of ester polymers, including PET, using microwave and alkaline salts such as NaOH and KOH as homogeneous catalysts. Terephthalic acid or the salts of terephthalic acid are obtained. However, the subsequent neutralisation of the basic reaction conditions is not economical from the industrial perspective.
Song et al. (Journal of Applied Polymer Science, Vol. 117, 3155-3159 (2010)) discloses a method of chemical recycling using metal oxide catalysts (MgO, Fe2O3, Gr2O3, ZnO, SnO, Sb2O3, Cu2O, TiO2, and MnO2), microwaves and water as solvent for PET hydrolytic depolymerisation. Therefore, this process does not use glycolysis and the product obtained is terephthalic acid (TPA). This process also requires waste solvent to be neutralised.
Siraphat Putisompon, et al (Key Engineering Material, Vol. 824, pp 225-230, 2019) discloses a method of chemical recycling using CaO as a catalyst with ethylene glycol as a solvent for PET depolymerisation using thermal heating with a depolymerisation time of two hours. CaO catalysts derived from shells were used in this reaction. After the reaction, the product is precipitated by adding water to the mixture with ethylene glycol. Therefore, this process does not allow the reuse of ethylene glycol, unless purified by distillation, and due to the presence of water, the catalyst cannot be recovered.
US2009/0318579 describes a method for depolymerizing a polyester. The method involves irradiating the polyester with microwaves in the presence of an alkylene glycol with dispersed titanium oxide (TiO2) fine powder.
JP2013057006 describes a method of depolymerizing polyester. The method comprises irradiating with microwave in the presence of an alkylene glycol in which a metal oxide powder is dispersed.
The current invention solves to alleviate the above problems.
The current invention provides a method for recycling plastic products, such as low-value polyester and PET sources, e.g., mixed plastics, textiles, carpet fibres or similar, and the optional subsequent conversion of the chemical species formed during the recycling process into plastics of higher value (upcycling). The method involves depolymerising PET into its basic components (monomers) and optionally re-polymerising the components back into PET or into plastics of higher value. These higher value plastics may be polybutylene adipate terephthalate (PBAT) and polybutylene terephthalate (PBT).
The method of the invention is particularly effective in view of the catalyst used. The catalyst, such as calcium oxide, is cheaper and more environmentally friendly than the catalyst used in the prior art, such as titanium oxide.
The toxicity derived from the possible residual content of the catalyst within the product is significantly reduced. In terms of reactivity, the catalyst used by the current inventors is surprisingly more efficient than other known catalysts, such as titanium oxide, with, for example, CaO depolymerising PET with a yield of 99%. The high reactivity allows the method of the invention to obtain a depolymerisation product as a highly crystalline product, in high purity, that precipitates after the reaction, due to the low concentration of oligomers. This simplifies the overall process as there is no need to add additional solvents.
In a first aspect, the current invention provides a method for recycling (depolymerisation) a plastic product, the method comprising:
In an embodiment, the catalyst is a metal oxide.
In an embodiment, the catalyst is heterogenous. It may be a powder.
Preferably, the plastic product comprises polyethylene terephthalate (PET). The plastic product may consist of PET.
The method is one of depolymerisation and the reaction product comprises, or consists of, the depolymerisation product, i.e., monomers.
In an embodiment, the catalyst comprises (or consists of) a catalyst selected from the group comprising calcium oxide, zinc oxide (ZnO), magnesium oxide (MgO), iron oxide (Fe2O3), or a catalyst derived or prepared with calcium oxide and a triol, such as calcium glyceroxide, or any combination thereof.
In an embodiment, the catalyst comprises (or consists of) CaO mixed with any one of zinc oxide (ZnO), magnesium oxide (MgO), iron oxide (Fe2O3), or calcium glyceroxide.
Preferably, the catalyst is a heterogenous metal oxide, preferably, calcium oxide (CaO) or zinc oxide (ZnO).
Typically, the heterogenous metal oxide is CaO.
In an embodiment, the catalyst may be a catalyst derived from or prepared using CaO. The catalyst may be calcium glyceroxide.
Preferably, the catalyst is nanostructured.
Preferably, the solvent is selected from ethylene glycol and butylene diol (1, 4-butanediol).
Typically, the method further comprises a step of recovering or purifying the depolymerisation product. This may be a step of crystallising the depolymerisation product
Preferably, the method further comprises a step of solvent recovery and/or a step of catalyst recovery. This may be by filtration.
In an embodiment, the catalyst is dispersed in the solvent prior to addition of the plastic product. Preferably, the catalyst and solvent are stirred and/or agitated prior to adding the plastic product.
Typically, the plastic product is PET or a PET containing product.
In an embodiment, the solvent is ethylene glycol, and the reaction product comprises BHET.
In an embodiment, the solvent is 1, 4-butanediol, and the reaction product comprises BHBT.
In an embodiment, the reaction mixture may optionally comprise a microwave absorber. The microwave absorber may be selected form the group comprising sodium chloride, sodium bromide, sodium iodide, sodium fluoride, lithium chloride, potassium chloride, magnesium chloride, calcium chloride and activated charcoal.
An aspect of the current invention provides a method of converting PET into bis-hydroxy ethylene terephthalate (BHET), the method comprising
An aspect of the current invention provides a method of converting PET into bis-hydroxy butylene terephthalate (BHBT), the method comprising
In an embodiment, the catalyst comprises (or consists of) a catalyst selected from the group comprising calcium oxide, zinc oxide (ZnO), magnesium oxide (MgO), iron oxide (Fe2O3), or a catalyst derived or prepared with calcium oxide and a triol, such as calcium glyceroxide, or any combination thereof.
The catalyst used may be any of the catalysts of the method of the invention described herein.
Where used herein and unless specifically indicated otherwise, the following terms are intended to have the following meanings in addition to any broader (or narrower) meanings the terms might enjoy in the art:
Unless otherwise required by context, the use herein of the singular is to be read to include the plural and vice versa. The term “a” or “an” used in relation to an entity is to be read to refer to one or more of that entity. As such, the terms “a” (or “an”), “one or more,” and “at least one” are used interchangeably herein.
As used herein, the term “comprise,” or variations thereof such as “comprises” or “comprising,” are to be read to indicate the inclusion of any recited integer (e.g., a feature, element, characteristic, property, method/process step or limitation) or group of integers (e.g., features, element, characteristics, properties, method/process steps or limitations) but not the exclusion of any other integer or group of integers. Thus, as used herein the term “comprising” is inclusive or open-ended and does not exclude additional, unrecited integers or method/process steps.
“Recycling” is the process of converting materials, such as plastic waste materials, into new materials and objects. Ideally the new material is a reusable material.
As used herein the term “depolymerisation” refers to a process of converting a polymer into a monomer or a mixture of monomers. The monomer(s) is the “depolymerisation product”
As used herein the term “heterologous catalyst” refers to a catalyst in a phase different form that of the reactants in a reaction.
As used herein the term “nanostructured” refers to a material that has a size of 1 to 100 nm.
As used herein the term “polyethylene terephthalate (PET), is a thermoplastic resin. It is commonly used in fibres for clothing and containers such as plastic bottles. It consists of polymerised units of the monomer ethylene terephthalate with repeating C10H8O4 units. In this context, PET may be provided as PET or as a plastic product comprising PET. It has the following chemical structure:
As used herein the term “crystallisation” refers to the process of producing solid crystals from a solution. In general, a solvent evaporates leaving a concentrated solution.
As used herein the term “plastic product” refers to a synthetic, semi-synthetic or naturally occurring material comprising a polymer as the main component. Preferably, the polymer is PET. The plastic product may be any known plastic product, such as a waste product, or container. Examples include but are not limited to textiles, bottles, cosmetic containers and food containers. The plastic product may be at least one plastic product, i.e., a combination of plastic products.
As used herein the term “microwave irradiation” is a form of electromagnetic radiation with wavelengths ranging from about 1 metre to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively.
“Ethylene glycol” is an organic compound with the formula (CH2OH)2.
“1,4-Butanediol” is an organic compound with the formula C4H10O2 or HO(CH2)4OH
As used herein the term “catalyst support” is a material, usually with a high surface area, to which a catalyst is affixed. A “supported catalyst” is a catalyst with a support.
A triol is a chemical compound containing three hydroxyl groups. One example is glycerol. Further examples include pentane-1,3,4-triol, propane-1,2,3 triol, cyclohexane-1,2,3-triol, butane-1,2,4-triol, Butane-1,1,3-triol, pentane-1,3,4-triol, cyclohexane-1,2,3-triol, propane-1,2,3-triol and glycerin.
A “coordination complex” is a compound or ion with a central, usually metallic, atom or ion combined by coordinate bonds with a definite number of surrounding ions, groups or molecules.
The current invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying Figures in which;
All publications, patents, patent applications and other references mentioned herein are hereby incorporated by reference in their entireties for all purposes as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference and the content thereof recited in full.
The method of the invention uses the combination of a catalyst, such as a heterologous metal oxide catalyst, and a microwave energy source to depolymerise PET into its basic components (monomers) and optionally re-polymerise the components back into PET or into plastics of higher value.
In an embodiment, the plastic product is processed prior to addition to the reaction mixture. For example, it may be washed and/or cleaned. It may be broken, or cut, crushed and/or shredded. These types of processing steps prior to recycling are known in the art.
The solvent and catalyst maybe combined and optionally stirred and/or agitated, prior to the addition of the plastic product to the reaction mixture.
Typically, the reaction mixture is agitated or stirred prior to exposing to the energy source.
Of note, in an embodiment, the current invention employs a heterogeneous metal oxide catalyst, such as CaO or ZnO, MgO or Iron oxides. Iron oxide may be Iron (III) oxide, namely Fe2O3. It may be FeO or Fe3O4. It may be a mixture of one or more of the catalysts, such as any of the catalysts mixed with CaO.
In an embodiment, the catalyst may be nanostructured. Typically, the catalyst is dispersed in the solvent. Advantageously, the catalyst used in the current invention can be easily separated and recovered, thus reducing the amount of purification steps required for the isolation of the product after PET depolymerisation. The catalyst is also easily regenerable or reusable. No aqueous treatment step is necessary when using a heterogenous catalyst.
In an embodiment, the catalyst is one derived, or prepared, from CaO. This is called a coordination complex catalyst. One example is calcium glyceroxide. This is prepared from CaO, and a triol, such as glycerol. It is prepared in a stoichiometric quantity, and the method uses a solvent, such as methanol.
Methods to produce such catalysts, e.g., calcium glyceroxide are known in the art, for example, Laura Leon-Reina et al, (Journal of Catalysis, Volume 300, April 2013, pages 30-36). A suitable method is also described herein in the Examples. During the preparation of the catalyst, the thiol such as glycerol coordinates to calcium to form a coordination complex. This is insoluble during the depolymerisation conditions. Therefore, it is easy to recover. Calcium glyceroxide acts as a heterogenous catalyst during the depolymerisation.
In an embodiment, the catalyst may be dissolved in a triol, such as glycerol, to be homogenous catalyst. In this embodiment, the homogenous catalyst is prepared from CaO dissolved in an excess amount of glycerol, so the glycerol is acting as a coordinating agent and as solvent of the prepared catalyst.
The catalyst may be a supported catalyst, for example supported CaO catalyst. Supports are known in the art. Examples of supported include but are not limited to activated carbon and activated charcoal. This applies to any one of the catalysts disclosed herein. Examples of supported catalysts include but are not limited to supported CaO/MgO, activated carbon supported CaO, MgO and iron oxides, nano CaO, CaO on AC (activated carbon and activated charcoal) supports, Fe3O4/AC, ZnO/CaO mixture, MgO/AC, ZnO/AC and Fe2O3/AC.
In a typical reaction, the catalyst is included in the reaction mixture in a concentration of 0.1% to 2%, typically 1% by weight of PET, or 1.5% by weight of PET.
The plastic product is included in the reaction mixture in any suitable amount, e.g., from 0.5 g to 10 g PET, from 1 to 5 g PET, typically 1 to 2 g PET.
Plastic product, e.g., PET, and solvent are used in a 10:1 ratio (w/w %). The ratio may be 20:1, 15:1, 10:1, or 5:1.
In a preferred embodiment, the reaction mixture comprises 1 g of PET, 0.05 g of catalyst and 10 ml of solvent.
Notably, the current invention uses microwave as an energy source. This substantially reduces the amount of time and energy required compared with prior art methods which use thermal heating, with the use of a cheap and non-toxic catalyst that can be easily separated and recovered. For example, using a CaO catalyst together with microwave energy, the depolymerisation of a plastic comprising PET can take less than 3 minutes. Using the same catalyst with thermal heating can take two hours for depolymerisation.
The temperature of the microwave irradiation is one sufficient to produce a reaction product comprising a depolymerisation product. It is preferably at least, or at, the boiling point of the solvent. For example, when ethylene glycol is used as a solvent, the heating step by microwave energy is from 190° C. to 200° C., preferably about 197° C. When 1, 4-butanediol is the solvent the temperature is from 225° C. to 235° C., preferably about 230° C.
The time of this step is one suitable for the depolymerisation reaction to complete. For example, 30 minutes or less, 25 minutes or less, 20 minutes or less, 15 minutes or less, 12 minutes or less, 10 minutes or less, 10 minutes or less, 9 minutes or less, 8 minutes or less, 7 minutes or less, 6 minutes or less, 5 minutes or less, 4 minutes or less, 3 minutes or less, or 2 minutes or less. Typically, it is from 1 to 30 minutes, from 5 to 25 minutes, from 10 to 15 minutes. It will be appreciated that the time depends on the plastic product used.
Following irradiation or exposure to the heating source,
The produced product, or depolymerisation product, obtained depends on the solvent used and this can be manipulated or tuned by the user by changing the type of solvent used in the method of the invention. For example, when ethylene glycol is used as a solvent bis-hydroxy ethylene terephthalate (BHET) is the predominant depolymerisation product produced. This method uses glycolysis for depolymerisation. When butylene diol is used as a solvent, the predominant product produced is bis-hydroxy butylene terephthalate (BHBT). This method also uses glycolysis for depolymerisation.
The depolymerisation product can subsequently be polymerised, or re-polymerised, into a higher value polymer, e.g., PET. The type of product produced depends on the starting depolymerisation product. BHET can subsequently be used to regenerate PET and BHBT can be used to produce biodegradable polymers such as PBT or PBAT. PBAT is a promising candidate as a biodegradable packing material and could be used in products such as food grade plastic bottles. Thus, the method of the invention may further comprise a step of polymerisation of the depolymerised product to generate polymer. Methods of polymerisation are known in the art. For example, Denial Mahata, et al., (Poly(butylene adipate-co-terephythalate) polyester synthesis process and product development. Polym. Sci. Ser. C 63, 102-111 (2021)) and H Shah, et al., (Aspects of the chemistry of poly(ethylene terephthalate): 5. Polymerization of bis(hydroxyethyl) terephthalate by various metallic catalysts, Polymer, volume 25, issue 9, 1984).
When the depolymerisation product is produced, such as BHET, advantageously no extra separation steps are required for isolating the product, such as distillation used in conventional chemical recycling processes. Instead, high purity BHET is provided. This may be by any known means. The monomer product, e.g., BHET monomer product, is recovered or purified. This may be a means for recovery known in the art. It includes a step of crystallisation or extraction. Extraction may be by using solvents such as chloroform or dichloromethane DCM. Preferably, the step of recovery is by crystallisation.
After depolymerisation the reaction and prior to purification/recovery, the reaction is normally cooled to stop the reaction. This may be to approximately 100° C. This can be by any means known in the art, e.g., by leaving it at room temperature. Preferably, it is cooled using a water bath.
In the current method, preferably purification/recovery is by crystallisation in solution. Generally, it is crystallised from the mother liquor with a with a purity of >95% as determined by nuclear magnetic resonance (NMR) analysis. Methods of NMR are known in the art. For example, Ritter Lima et al., (Titanate nanotubes as new nanostructured catalyst for depolymerisation of PET by glycolysis reaction, Articles Mat. Res. 20 (suppl 2) 2017).
This crystallisation step reduces both solvent use and energy used in the overall process, compared with conventional chemical recycling which extract the product using solvents.
In an embodiment, the purity of the depolymerisation product is equal to or greater than 80%, 85%, 90%, 95%, or 98%, or 100%. Typically, it is between 90% and 100%, or from 95% to 98%. Preferably, the purity is greater than 95%.
The recovered product can then be separated by any known means form the mother liquor. Typically, separation is by filtration.
The method comprises a step of solvent recovery and/or a step of catalyst recovery. This may be by means for recovery known in the art. It includes filtration. Typically, this step is after purification/recovery of the depolymerisation product, e.g., after crystallisation.
Alternatively, the catalyst recovery system could be an aqueous/organic mixture. In such a means, the catalyst is dissolved in the aqueous phase and the reagents are in the organic phase. Distillation and condensation can be used to separate and recover solvent from other liquids. Removal efficiency can be very high using this type of process and can be used for solvent mixtures as well as single solvents.
In an embodiment, the method comprises an initial pre-treatment step when the plastic product comprising PET comprises (or consists of) a mixture of PET and cotton (polycotton), such as a textile. PET and cotton are separated, by any known means, prior to depolymerisation, i.e., prior to addition to the reaction mixture. In one embodiment, product is separated by being placed in a suspension of glycerol, or ethylene carbonate, and subjected to microwave irradiation. It may be for 1 minute to 10 minutes, typically about 2 minutes. It will be appreciated that the time is one sufficient to allow separation. Cotton is recovered, typically by filtration and separated. PET is dissolved in glycerol is crystallised and separated, typically by filtration, optionally washed with water and dried. It is then ready to use in the method of the invention.
In the method of the current invention, the PET may be coloured PET. Coloured PET can be depolymerised without interfering with the crystallisation process. Using coloured PET for recycling can cause several issues, such as the purity of the final product. Usually, further steps of purification are needed when a coloured plastic is used as the starting product. However, the current method can provide pure (colourless) crystals from coloured mother liquor. This is important to reduce the cost of recycling and prevent the use of hazardous solvents.
In an embodiment, the reaction mixture may optionally comprise a microwave absorber or microwave absorbing material. The microwave absorber may be selected form the group comprising sodium chloride, charcoal, activated charcoal, sodium bromide, sodium iodide, sodium fluoride, lithium chloride, potassium chloride, magnesium chloride and calcium chloride. This functions to dissipate electromagnetic waves by converting it into thermal energy.
The method of the current invention provides a conversion of equal or greater than 75%, equal or greater than 80%, equal or greater than 85%, equal or greater than 90%, equal or greater than 95%, equal or greater than 98%, 99%, or 100%. Typically, the conversion is equal or greater than 80%, or from 80% to 90%, or 80% to 95%. The method of the current invention provides a yield of greater than or equal to 80%.
An aspect of the invention provides a reaction product produced by any one of the methods of the invention.
It will be appreciated that any embodiment or feature described herein may be combined. In addition, any embodiment or feature described herein may be used in any one of the described aspects of the invention.
The invention will now be described with reference to specific Examples. These are merely exemplary and for illustrative purposes only: they are not intended to be limiting in any way to the scope of the monopoly claimed or to the invention described. These examples constitute the best mode currently contemplated for practicing the invention.
One gram (1 g) of PET was added into 100 ml round bottom flask and followed by the 0.1 g of CaO catalyst to PET. Ethylene glycol was added into a round bottom flask and stirred for mixing all starting materials. This mixture was heated to the boiling point of ethylene glycol (˜200° C.) in a microwave, the glycolysis reaction was allowed to proceed for 2 to 4 min, after which time the temperature of the solution lowered to about 100° C. in a water bath to stop the reaction. The hot solution of BHET was filtered by filtration. The filtrate cooled down to room temperature to obtain a precipitate of BHET. The products formed from the depolymerisation of PET were characterised by NMR and X-ray diffraction analysis.
1H NMR data of the products obtained can be summarised as follows: protons of an aromatic ring (δH=8.1 ppm, s, 4H), hydroxyl groups (δH=4.95 ppm, t, 2H), methylenes (—CH2—) adjacent to the —OH groups (δH=3.73 ppm, m, 4H), methylenes (—CH2—) adjacent to the —COO groups (δH=4.33 ppm, t, 4H), indicative of the formation of BHET. A signal observed at approximately 2.5 ppm can be assigned to the solvent DMSO and peaks at 3.3 and 2.0 ppm were attributed to residual H2O and contamination. 13C NMR data of the products showed the following peaks: (δC=165.65 ppm), (δC=134.24 ppm), (δC=129.96 ppm), (δC=67.48 ppm) and (δC=59.48 ppm), which can be assigned to the carbons of the chemical structure of BHET. The signal from DMSO appeared at 40 ppm.
X-ray diffraction data of the crystals obtained from the glycolysis of polyester fibres in ethylene glycol also confirmed the presence of BHET as the major product formed (see Table 1).
To a 50 ml flask containing CaO (0.1 g) was charged 1,4-butanediol (10 ml) and PET (1 g). The flask was heated using microwave energy with stirring C for 3 minutes. The slurry turned into a homogeneous liquid in 3 minutes. The reaction mixture was dissolved in chloroform (50 mL) and washed with water (100 mL). The organic layer was then stirred, evaporated, and dried in vacuum to give the product bis(4-hydroxybutyl) terephthalate (BHBT) (0.9 g, 90%).
1 g of Calcium oxide was combined with 3 g of glycerol and 10 ml of methanol. The combined mixture was heated to 60 C for 5 hours and the resulting solids was filtrated and dried overnight to yield calcium glyceroxide.
Depolymerisation Procedure with Calcium Glyceroxide as Catalyst
One gram (1 g) of PET was added into 100 ml round bottom flask and followed by the 0.1 g of Calcium glyceroxide catalyst to PET. Ethylene glycol was added into a round bottom flask and stirred for mixing all starting materials. This mixture was heated to the boiling point of ethylene glycol (˜200° C.) in a microwave, the glycolysis reaction was allowed to proceed for 2 to 4 min, after which time the temperature of the solution lowered to about 100° C. in a water bath to stop the reaction. Calcium glyceroxide was recovered by hot filtration and reused. BHET was recovered by filtration of the remaining solution after cooling down to room temperature. The BHET product formed from the depolymerisation of PET was characterised by NMR and IR.
The foregoing description details presently preferred embodiments of the present invention. Numerous modifications and variations in practice thereof are expected to occur to those skilled in the art upon consideration of these descriptions. Those modifications and variations are intended to be encompassed within the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21213470.4 | Dec 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/085265 | 12/9/2022 | WO |
