A method for separating materials constituting a complex multi-layer using acidophilic bacteria

Abstract

The present invention relates to a process for separating the layers constituting a complex multilayer. The process preferably comprises at least one step of contact (preferably by immersion) between the multilayer and a treatment mixture comprising acidophilic bacteria and optionally at least one fungus belonging to the phylum Ascomycota. Furthermore, the present invention relates to a treatment mixture for separating the layers of the multilayer.

Description

[Technical field]

[0001] The present invention relates to a method for separating materials that make up a composite multi-layer. [Background technology]

[0002] Disposable packaging is very widely present on the market and is used on all occasions to store, transport and protect food and beverages. For the most part, this packaging is made up of several layers joined together and constitutes a mass of so-called high-risk waste. In fact, recovering the individual layers that make up this packaging is very difficult and expensive, both in economic and environmental terms.

[0003] In fact, the techniques used to date are limited to recovering cellulose intended for paper manufacture, while plastics and metals, mainly aluminum-made components, are not recovered; otherwise, they are recovered to a minimum. In most cases, composite aluminum and plastic wastes are simply crushed and used to manufacture goods. Thus, if aluminum is not isolated, its high value as a raw material is not utilized. Processes are known that use pyrolysis for subsequent energy generation to produce liquid and gaseous fuels. However, these processes, despite producing fuel, require large amounts of energy, which is supplied by burning part of the waste itself, since the process of pyrolysis involves a highly endothermic reaction.

[0004] Additionally, many processes have been described to separate aluminum and plastic from waste packaging made from aluminized plastics using solvents including tetrahydrofuran, caustic soda, xylene, and toluene. However, for the most part, these processes use toxic and carcinogenic solvents that do not allow for complete recovery of aluminum in its original metallic form.

[0005] There is therefore a great need for sustainable processes that do not use polluting compounds and that can recover not only the cellulose but also the plastics and metals contained in multi-layer packaging. Summary of the Invention

[0006] A first aspect of the invention relates to a method for separating the layers constituting a composite multilayer. Preferably, the process comprises at least one step of contact, preferably by immersion, between the multilayer and a treatment mixture comprising acidophilic bacteria and optionally at least one fungus belonging to the phylum Ascomycota. Preferably, the bacteria and optionally at least one fungus are dispersed in a water-based acidic composition having a pH between 2.5 and 4, preferably between 2.7 and 3.5. In one embodiment, the multilayer is maintained in contact with the treatment mixture at a temperature between 30 and 70°C for 20 to 50 minutes, more preferably at a temperature of 40°C.

[0007] A second aspect of the invention relates to a treatment mixture for separating the constituent layers of a composite multi-layer. In one embodiment, the treatment mixture comprises an acidophilic bacterium and optionally at least one fungus belonging to the phylum Ascomycota. Preferably, the treatment mixture has a pH between 2 and 5, preferably between 2.5 and 4.5.

[0008] In one embodiment, the present invention relates to a process for recycling a composite multi-layer, comprising a step of separating the constituent layers of the multi-layer by at least one contact, preferably by immersion, between the multi-layer and a treatment mixture comprising acidophilic bacteria and optionally at least one fungus belonging to the phylum Ascomycota.

[0009] When the multi-layer is used to package food or other products, the method of the present invention is a method for recycling waste packaging.

[0010] definition

[0011] In the context of the present invention, composite multilayer or multi-layer means a waterproof material comprising at least two layers, preferably a plurality of layers. These layers consist of different materials, they are generally layers of polyethylene, paper, and / or aluminum laminated together. Composite multilayers are generally, but not exclusively, used for food grade packaging. Detailed description of the invention

[0012] A first aspect of the invention relates to a method for separating layers that make up a composite multilayer.

[0013] In one embodiment, said multilayer comprises at least one layer, more preferably multiple layers, of a polymeric material, preferably a thermoplastic polymer, more preferably selected from polyethylene, polystyrene, polycarbonate, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), and combinations thereof.

[0014] In one embodiment, said multiple layers include at least one layer comprising cellulose, such as paper and / or cardboard.

[0015] In one embodiment, said multi-layer comprises at least one layer of polymeric material and at least one layer comprising cellulose, such as paper and / or cardboard.

[0016] In a preferred embodiment of the invention, said multilayer comprises at least one layer of polymeric material and at least one layer comprising a metal, preferably comprising aluminium.

[0017] In a preferred embodiment of the invention, said multi-layer comprises at least one layer comprising cellulose, e.g. paper and / or cardboard, and at least one layer comprising metal, preferably including aluminium.

[0018] In one embodiment, the multilayer comprises at least one layer of polymeric material, at least one layer of cellulosic (eg, paper and / or cardboard), and at least one layer of metal (preferably aluminum).

[0019] to this point In one embodiment, the method comprises at least one step of contact (preferably by immersion) between the multilayer and a treatment mixture comprising acidophilic bacteria and optionally at least one fungus belonging to the phylum Ascomycota. Preferably, the bacteria and optionally at least one fungus are dispersed in an acidic composition, such as for example fermented acid milk or acetate, having a pH between 2.5 and 4, preferably between 2.7 and 3.5.

[0020] In one embodiment, the method comprises at least one step of contacting the multilayer with a treatment mixture comprising an acidic composition, preferably fermented acid milk, acidophilic bacteria belonging to at least two, preferably at least three families selected from Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiaceae and Acetobacteraceae, and optionally at least one fungus belonging to Amphiphaeraceae and / or Trichocomataceae and / or Davidiellaceae. The multilayer is preferably kept in contact with the mixture at a temperature of 20-60°C, preferably 30-45°C, for a period of 2 minutes to 24 hours.

[0021] In one embodiment of the present invention, the Lactobacillaceae bacteria belong to the genus Lactobacillus, the Pseudomonadaceae bacteria belong to the genus Pseudomonas, the Moraxellaceae bacteria belong to the genus Acinetobacter, the Rhizobiumaceae bacteria belong to the genus Rhizobium, and the Acetobacteraceae bacteria belong to the genus Acetobacter. The Lactobacillus bacteria preferably belong to the species L. plantarum, and more preferably the L. plantarum bacteria are L. plantarum K21 Stocks and L. plantarum PS128 strains.

[0022] In one embodiment, the at least one fungus belonging to the family Amphisphaeriaceae belongs to the genus Pestalotiopsis, the at least one fungus belonging to the family Trichocomaceae belongs to the genus Aspergillus, and the at least one fungus belonging to the family Davidiellaceae belongs to the genus Cladosporium.

[0023] In one embodiment, the process of the present invention comprises the following steps. a) making available a processing mixture which contains: an acid composition, preferably fermented acid milk, - bacteria belonging to at least two, preferably at least three, families selected from the family Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiaceae and Acetobacteraceae, and - optionally at least one fungus belonging to the families Amphisphaeriaceae and / or Trichocomaceae and / or Davidiellaceae, b) contacting the multilayer with the treatment mixture made available in step a) at a temperature between 20 and 80° C. for a period between 20 minutes and 24 hours.

[0024] Preferably, step a) comprises the following sub-steps: a) maintaining the milk at a temperature of 15-25° C. for 5-8 days and / or until it reaches a pH of 2.5-4, preferably a pH of 2.7-3.5; a2) adding acidophilic bacteria; a) fermenting the mixture at a temperature of 20 to 35° C. for 50 to 80 hours; and optionally a4) adding said at least one fungus.

[0025] Preferably, in step a2), the bacteria are added in an amount of 5 to 14% by weight (W / W), more preferably 8 to 12% by weight (W / W), relative to the weight of the fermented acidic milk.

[0026] The pH of the treatment mixture is preferably from 2 to 5, preferably from 2.5 to 4.5.

[0027] In one embodiment, in step a4) the at least one fungus is mixed with a salt, preferably selected from sodium bicarbonate, potassium alum, and combinations thereof. Preferably, the amount of said salt is between 2 and 8% by weight, preferably between 3 and 7% by weight (W / W) relative to the weight of the at least one fungus. In one embodiment, step a4) comprises adding a solvent, for example water. Preferably, an amount of solvent, preferably water, of 30 to 50% by weight relative to the weight of the at least one fungus is added.

[0028] The at least one fungus is preferably broken into fragments, preferably crushed or chopped.

[0029] In one embodiment, said multi-layer comprises at least one layer, and more preferably multiple layers, of polymeric material.

[0030] In one embodiment, said multiple layers include at least one layer comprising cellulose, such as paper and / or cardboard.

[0031] In one embodiment, said multi-layer comprises at least one layer of a polymeric material and at least one layer comprising cellulose, such as paper and / or cardboard.

[0032] Preferably, to separate the multi-layers comprising one or more layers of polymeric material and optionally at least one layer of cellulose, the treatment mixture comprises an acidic composition, preferably fermented acidic milk, bacteria belonging to at least two, preferably at least three families selected from Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiaceae and Acetobacteraceae, and at least one fungus belonging to Amphiphaeraceae and / or Trichocomataceae and / or Davidiellaceae. The pH of said treatment mixture is preferably between 2.5 and 4, more preferably between 2.7 and 3.5.

[0033] In a preferred embodiment of the invention, said multilayer comprises at least one layer of a polymeric material and at least one layer comprising a metal, preferably aluminium.

[0034] In a preferred embodiment of the invention, said multi-layer comprises at least one layer comprising cellulose, e.g. paper and / or cardboard, and at least one layer comprising metal, preferably aluminium.

[0035] In one embodiment, said multilayer comprises at least one layer of a polymeric material, at least one layer comprising cellulose, e.g. paper and / or cardboard, and at least one layer comprising a metal, preferably aluminium.

[0036] Preferably, to separate the multiple layers comprising one or more layers of metal, one or more layers of polymeric material and optionally at least one layer comprising cellulose, the treatment mixture comprises an acidic composition, such as fermented acidic milk, bacteria belonging to at least two, preferably at least three families selected from Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiaceae and Acetobacteraceae. The pH of the treatment mixture is preferably 2.5-4, more preferably 3-5, even more preferably 3.5-4.5.

[0037] In a preferred embodiment of the present invention, in step b) the multilayer body is kept in contact with the mixture obtained in step a) for 2 to 50 minutes at a temperature between 30 and 70° C., more preferably between 40 and 50° C. Preferably, the multilayer body is immersed in the mixture.

[0038] In one embodiment, step b) is carried out statically, ie, without stirring the treatment mixture and the multilayer.

[0039] Alternatively, step b) is carried out under stirring, preferably by mechanical stirring of the treatment mixture.

[0040] After step b), the materials constituting the multiple layers, separated from one another, are preferably recovered from the treatment mixture.

[0041] In one embodiment, after the materials making up the multiple layers are recovered, the treatment mixture is recovered and made available for further use in the process as described above.

[0042] The applicant has surprisingly found that by placing a multi-layer, for example a food packaging, in contact with the above-mentioned treatment mixture, it is possible to obtain a separation of the various materials that make up the multi-layer. In particular, the applicant has advantageously found that the above-mentioned process makes it possible to separate a layer of polymeric material, such as a plastic material, from a layer of metal, such as aluminum. The various layers that have been separated from one another by this process can be recycled to produce new materials. For example, the treated and separated polyethylene can also be reused in combination with other plastic materials to obtain a stable composite plastic material.

[0043] Furthermore, the process can be applied to the entire multi-layer or to the remaining multi-layer after the paper has been removed. In the latter case, it is placed downstream of the recycling process at the paper mill.

[0044] In one embodiment, the present invention relates to a method for recycling a composite multi-layer comprising a step of separating the layers constituting the multi-layer by at least one contact, preferably immersion, between the multi-layer and a treatment mixture comprising acidophilic bacteria and optionally at least one fungus belonging to the phylum Ascomycota, preferably the treatment mixture is as described in detail above.

[0045] When the multi-layer is used to package food or other products, the method of the present invention is a method for recycling waste packaging.

[0046] A second aspect of the invention relates to a treatment mixture for separating the materials constituting a composite multilayer. In one embodiment, the treatment mixture comprises an acidophilic bacterium and optionally at least one fungus belonging to the phylum Ascomycota. Preferably, the treatment mixture further comprises an acidic composition having a pH of 2.5 to 4, preferably 2.7 to 3.5, such as fermented acid milk or acetate.

[0047] In one embodiment, the treatment mixture comprises an acidic composition, preferably fermented acidic milk, acidophilic bacteria belonging to at least two, preferably at least three families selected from Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiaceae and Acetobacteraceae, and optionally at least one fungus belonging to the Amphiphaeraceae and / or Trichocomataceae and / or Davidiellaceae families.

[0048] In one embodiment of the present invention, the bacterium of the Lactobacillaceae family belongs to the genus Lactobacillus, the bacterium of the Pseudomonadaceae family belongs to the genus Pseudomonas, the bacterium of the Moraxellaceae family belongs to the genus Acinetobacter, the bacterium of the Rhizobium family belongs to the genus Rhizobium, and the bacterium of the Acetobacteraceae family belongs to the genus Acetobacter.The bacterium of the Lactobacillus genus is preferably of the species L.plantarum, and more preferably the bacterium of the species L.plantarum is selected from the strain L.plantarum K21 and the strain L.plantarum PS128.

[0049] In one embodiment, the at least one fungus belonging to the Amphiperiaceae family belongs to the genus Pestalotiopsis, the at least one fungus belonging to the Trichocomataceae family belongs to the genus Aspergillus, and the at least one fungus belonging to the Davidiellaceae family belongs to the genus Cladosporium.

[0050] The pH of the treatment mixture is preferably from 2 to 5, preferably from 2.5 to 4.5.

[0051] In one embodiment, the treatment mixture has a pH between 2.7 and 3.5, and in another embodiment, the treatment mixture containing at least one fungus has a pH between 3.5 and 4.5.

[0052] In one embodiment, the treatment mixture comprises a salt, preferably selected from sodium bicarbonate, potassium alum, and combinations thereof. Preferably, the amount of salt is 2-8% by weight, preferably 3-7% W / W, relative to the weight of the at least one fungus. In one embodiment, the mixture comprises a solvent, such as water, in an amount of 30-50% by weight, relative to the weight of the at least one fungus. EXAMPLES

[0053] Preparation of treatment mixture Mixture 1 Fermented acidic milk was prepared by leaving milk at room temperature for approximately 7 days until the pH reached 2.7–3.5. Acidophilic bacteria were then added at a rate of 10% by weight relative to the weight of the fermented acid milk, and the mixture was allowed to ferment for approximately 72 hours. The pH of mixture 1 is 2.7 to 3.5.

[0054] Mixture 2 Mixture 2 was obtained by adding fungi to Mixture 1. In detail, when the fermentation of Mixture 1 was completed, Fungi belonging to the genera Pestalotiopsis, Aspergillus, and Cladosporium were added.

[0055] Sodium bicarbonate was then added in an amount of 5% by weight relative to the weight of the fungus, and water was added in an amount of 30% by weight relative to the weight of the fungus. The pH of mixture 2 is 3.5 to 4.5.

[0056] Mixture 1 or Mixture 2 was heated under stirring at a temperature of 70° C. for 5 minutes. The multilayer was then immersed in mixture 1 or mixture 2 according to the scheme shown in Table 1.

[0057] Table 1 - Multi-layer separation scheme JPEG2025507158000001.jpg49133

Claims

1. 1. A process for separating materials constituting a composite multi-layer, comprising: (a) making available a treatment mixture comprising acidophilic bacteria belonging to at least two, preferably at least three, families selected from the family Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiumaceae and Acetobacteraceae; and (b) contacting said treatment mixture obtained in step (a) with said multilayer at a temperature of from 20 to 60° C. for a period of from 2 minutes to 24 hours.

2. 2. The process of claim 1, wherein the Lactobacillaceae bacteria belong to the genus Lactobacillus, the Pseudomonadaceae bacteria belong to the genus Pseudomonas, the Moraxellaceae bacteria belong to the genus Acinetobacter, the Rhizobiaceae bacteria belong to the genus Rhizobium, and the Acetobacteraceae bacteria belong to the genus Acetobacter.

3. 3. The process according to claim 2, wherein the bacterium of the genus Lactobacillus belongs to the species L. plantarum, preferably selected from the strains L. plantarum K21 and L. plantarum PS128.

4. The process of any one of claims 1 to 3, wherein the treatment mixture has a pH of from 2.7 to 3.

5.

5. 4. The process according to claim 1, wherein the treatment mixture comprises at least one fungus belonging to the family Amphispaellaceae and / or belonging to the family Trichocomataceae and / or belonging to the family Davidiellaceae.

6. 6. The process of claim 5, wherein at least one fungus belonging to the Amphiperiaceae family belongs to the genus Pestalotiopsis, at least one fungus belonging to the Trichocomataceae family belongs to the genus Aspergillus, and at least one fungus belonging to the Davidiellaceae family belongs to the genus Cladosporium.

7. The process of claim 5 or 6, wherein the treatment mixture has a pH of from 3.5 to 4.

5.

8. The process according to any one of claims 1 to 4, wherein the multilayer comprises at least one polymeric layer and optionally a layer comprising cellulose.

9. 8. The process according to any one of claims 1 to 3 or 5 to 7, wherein said multilayer comprises at least one polymeric layer, at least one layer comprising a metal, preferably aluminium, and optionally a layer comprising cellulose.

10. The process according to any one of claims 1 to 9, wherein the treatment mixture further comprises an acid composition selected from fermented acid milk and acetate, preferably fermented acid milk.

11. Step a) a) maintaining the milk at a temperature of 15-25° C. for 5-8 days and / or until it reaches a pH of 2.5-4, preferably a pH of 2.7-3.5; a 2) adding acidophilic bacteria; a3) fermenting at a temperature of 20-35° C. for 50-80 hours; and optionally 11. The process according to claim 1 or 10, further comprising the substep a4) of adding said at least one fungus.

12. 12. The process according to any one of claims 1 to 11, wherein in step b) the multilayer is maintained in contact with the treatment mixture made available in step a) at a temperature comprised between 30 and 70°C for a time comprised between 2 and 50 minutes.

13. A treatment mixture comprising bacteria belonging to at least two, preferably at least three families selected from the family Lactobacillaceae, Pseudomonadaceae, Moraxellaceae, Rhizobiumceae and Acetobacteraceae, wherein the Lactobacillaceae bacteria belong to the genus Lactobacillus, the Pseudomonadaceae bacteria belong to the genus Pseudomonas, the Moraxellaceae bacteria belong to the genus Acinetobacter, the Rhizobiumceae bacteria belong to the genus Rhizobium, and the Acetobacteraceae bacteria belong to the genus Acetobacter.

14. The mixture according to claim 13, wherein the bacteria of the genus Lactobacillus belong to the species L. plantarum, preferably selected from the strains L. plantarum K21 and L. plantarum PS128.

15. 15. The mixture according to claim 13 or 14, wherein the mixture comprises at least one fungus belonging to the family Amphispaellaceae and / or belonging to the family Trichocomataceae and / or belonging to the family Davidiellaceae.

16. 16. The mixture of claim 15, wherein at least one fungus belonging to the Amphiperiaceae family belongs to the genus Pestalotiopsis, at least one fungus belonging to the Trichocomataceae family belongs to the genus Aspergillus, and at least one fungus belonging to the Davidiellaceae family belongs to the genus Cladosporium.

17. The mixture according to any one of claims 13 to 14, wherein the mixture has a pH of from 2.7 to 3.

5.

18. The mixture according to any one of claims 13 to 16, wherein the mixture has a pH of from 3.5 to 4.

5.

19. 19. The mixture of any one of claims 13 to 18, wherein the treated mixture further comprises an acid composition selected from fermented acid milk and acetate.

Images