MULTILAYER MATERIAL THAT CAN BE USED AS PACKAGING, COMPRISING A LAYER OF CELLULOSE MATERIAL AND A LAYER OF MATERIAL COMPRISING AT LEAST ONE CASEIN AND / OR AT LEAST ONE CASEINATE

Abstract

The present invention relates to the field of multilayer materials that can be used as packaging. The object of the invention is to provide a cellulosic-based material that is recyclable, bio-based, biodegradable, and / or has improved barrier properties that can be used as packaging, e.g., in the food sector, and preferably can be easily produced. In particular, the present invention relates to a multilayer material comprising a layer of cellulosic material A and a layer of material B comprising at least one casein and / or at least one caseinate, water, and at least one plasticizer other than water, and optionally gelatin. The invention also relates to packaging made from this material, a product packaged with this packaging, and the manufacture of this material.

Description

Description Title of the invention: MULTILAYER MATERIAL THAT CAN BE USED AS PACKAGING, COMPRISING A LAYER OF CELLULOSIC MATERIAL AND A LAYER OF MATERIAL COMPRISING AT LEAST ONE CASEIN AND / OR AT LEAST ONE CASEINATE technical field

[0001] — This disclosure falls within the domain of multilayer materials that can be used as packaging. In particular, this disclosure relates to a material multilayer comprising a layer of cellulosic material A and a layer of material B comprising at least one casein and / or at least one caseinate. Technological background

[0002] The depletion of non-renewable resources, such as oil, and The increase in pollution linked to these resources leads to the development of alternative solutions that are less polluting and more environmentally friendly. In particular, with regard to packaging, the European Commission wishes that 100% of packaging be reusable, mechanically recyclable or com- postable by 2030 (Action Plan for the Circular Economy - 2020).

[0003] = In the food sector, the use of packaging made from cellulose materials po- potentially recyclable materials, such as paper or cardboard packaging, are developing. However, there are still major obstacles to the recyclability of this packaging. Furthermore, the use of recycled paper in these packages can also pose consumer safety issues.

[0004] — Indeed, single-use packaging for takeaway food and catering fast-acting ones always have a layer of plastic as a grease barrier, usually in polyamide (PA) or perfluoroalkyl substances (PFAS), for the convenience of consumers. This represents 65k tonnes discarded in Europe each year (by 2025) millions of individual packages produced).

[0005] — Furthermore, 17% of paper packaging is coated with a layer of plastic, to provide a barrier to gases, greases or water (in PE, PP, PET, PVDC, EVOH, or PVOH) to show the food inside, or to allow the sub- dability (sealing of the packaging).

[0006] Furthermore, recycled paper cannot be used in direct contact with food, due to the migration of mineral oils from the inks used in the Previous paper, for example in newspapers. A layer of plastic must It is now being used as a barrier for consumer safety. This prevents the widespread use of recycled paper in food packaging. When these packages are sorted, the removal of the plastic layer from the paper in recycling centers is a real problem which at best results in the loss of 10 to 20% of the paper fibers and at worst in the pollution of the batches of fibers by plastics which must then be burned or buried. It is therefore necessary to develop packaging that can counteract these disadvantages. In this context, the present invention aims to satisfy at least one of the following objectives. One of the objectives of the present invention is the provision of a recyclable material that can be used as packaging. One of the objectives of the present invention is the provision of a bio-based recyclable material that can be used as packaging. One of the objectives of the present invention is the provision of a recyclable material that can be used as packaging in the food sector. One of the objectives of the present invention is the provision of a biodegradable material that can be used as packaging. Another objective of the present invention is the provision of a material based on cellulosic materials, having improved barrier properties. One of the objectives of the present invention is the provision of a recyclable material that can be easily produced. Summary This disclosure relates to a multilayer material comprising: 1) At least one layer of cellulosic material A, and ii) At least one layer of material B comprising: a. At least one casein and / or at least one caseinate; b. Water, and € At least one plasticizer other than b). This disclosure also relates to a multilayered material obtained: - either by coating a layer of cellulosic material A with a solution S comprising: a. At least one casein and / or at least one caseinate; b. Water, and € At least one plasticizer other than b); - either by assembling a layer of cellulosic material A and a layer of material B comprising: a. At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer other than b), possibly by means of a binder, the assembly being preferably carried out by lamination or bonding. This disclosure also relates to packaging comprising a multi-layered material. This disclosure also relates to a product packaged in packaging comprising a multi-layered material. This disclosure also relates to a process for manufacturing a multilayer material, said process being carried out - either by coating a layer of cellulosic material A with a solution comprising: a At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer different from b); - either by assembling a layer of cellulosic material A and a layer of material B comprising: a At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer other than b), possibly using a binder, the assembly preferably being carried out by lamination or bonding The inventors discovered that such a multilayer material could be used as packaging. This multilayer material can be recycled in recycling centers without any modification to the lines or processes because the B material layer is water-soluble. Recycling centers will be able to recover nearly 100% of the cellulosic material fibers through simple mechanical filtration. The residues of the B material resulting from its solubilization will be biodegraded in the existing water treatment infrastructure at the recycling plants. Furthermore, the presence of a layer of material B improves the barrier properties of the multilayer material, particularly the barrier properties against fats and oxygen, making it suitable for use in the field of food packaging. Furthermore, material B is food-safe, 100% renewable, compostable, and biodegradable in marine environments, unlike most polymers used in packaging. Casein is an existing, documented ingredient in the food industry and is easily industrialized. Therefore, the multilayer material can be produced readily. Detailed description Unless otherwise stated, throughout this document, % are expressed as % by weight. By "packaging" we mean an object intended to contain and protect goods, to allow their handling and transport from the producer to the consumer or user, and to ensure their presentation, preservation, protection and / or use. The term “cellulosic material” refers, for example, to a material that can be derived from cellulose pulp. This cellulose pulp can be produced by chemical and / or mechanical processing, which is well known to those skilled in the art. This cellulose pulp can be derived from any suitable source such as wood, recycled wood, annual plants, agricultural residues (bagasse, straw, etc.), grasses (e.g., sugarcane, bamboo), or cardboard. By "thermoplastic" we mean, for example, a material which becomes malleable and foldable above a given temperature, the glass transition temperature Tg, but which below this Tg becomes hard again, these transformations being reversible. The term "biodegradable" refers, for example, to a material that can be broken down by microorganisms (bacteria, fungi, algae, etc.). The result of this decomposition is the formation of water, CO₂, and / or methane, and possibly byproducts (residues, new biomass) that are not toxic to the environment. This could be, for example, a material that is biodegradable according to the European standard EN NF 13432 and / or the French standard NF T 51-800. By "between x and y", we mean, for example, that the bounds x and y are included in the interval [x, y]. By "water-soluble," we mean, for example, something that dissolves in water. The water solubility of a material can be measured as follows: a piece of film (5 cm x 5 cm, cut with a punch) is attached to a slide holder and then immersed in a 1000 ml beaker containing 600 ml of distilled water at 20°C, while being stirred with a magnetic stir bar at 300 rpm. The time it takes for the film to break through is measured. The film's disintegration results in the formation of film particles. The test lasts 10 minutes, after which the particles are passed through a 0.5 mm sieve to check their size. When no particles are found on the sieve, the film is considered water-soluble. By "plasticizer" we mean, for example, a substance that lowers the glass transition temperature Tg of the material. By "hydrophobic," we mean, for example, a compound having little affinity with water and tending not to dissolve in it. Typically, it is a predominantly nonpolar compound. The term "hydrophilic" refers, for example, to a compound that has an affinity for water and tends to dissolve in it. Typically, this is a compound with polar groups capable of forming hydrogen bonds. By "surfactant", we mean, for example, an amphiphilic molecule, that is to say, a molecule possessing both hydrophilic and hydrophobic properties. The term "HLB" refers, for example, to the hydrophilic-lipophilic balance. The HLB value can be calculated using the following method: HLB = 20 x (Molar mass of the hydrophobic portion) / (Molar mass of the molecule). By "fatty acid" we mean, for example, an aliphatic monocarboxylic acid. By "bio-based", we mean, for example, a product made from materials of biological origin. The term "binder" refers, for example, to an agent that creates a bonding layer between the cellulosic material layer A and the material layer B. The binder used in the present invention may be a binder commonly used in the manufacture of multilayer materials, and in particular, multilayer films. Examples of such binders include hot-melt adhesives. Multilayer material The invention relates primarily to a multilayer material comprising: 1) At least one layer of cellulosic material A, and ii) At least one layer of material B comprising: a At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer different from b). This disclosure also relates to a multilayered material obtained: - either by coating a layer of cellulosic material A with a solution comprising: a. At least one casein and / or at least one caseinate; b. Water, and € At least one plasticizer other than b); - either by assembling a layer of cellulosic material A and a layer of material B comprising: a. At least one casein and / or at least one caseinate; b. Water, and € At least one plasticizer other than b), possibly using a binder, the assembly preferably being carried out by complexing or lamination: The multilayer material is preferably recyclable and / or bio-based. The multilayer material can be recyclable in accordance with Directive 2018 / 852 / EU of 30 May 2018. In one embodiment, the multilayer material is compostable, preferably according to standard NF T 51-800. The multilayer material can have a thickness between 0.01 and 100 mm, preferably between 0.05 and 50 mm. The cellulose material A is preferably selected from papers and cardboards. In one embodiment, the cellulose material A has a basis weight of between 20 and 500 g / m², preferably between 50 and 450 g / m². In another embodiment, the cellulose material A is selected from papers having a basis weight of between 20 and 225 g / m², and cardboards having a basis weight of between 225 and 500 g / m². The layer of cellulosic material A can have a thickness of between 0.01 and 50 mm, preferably between 0.05 and 20 mm. Cellulosic material A comprises cellulose, preferably at least 80% by weight, and preferably at least 90% by weight. Cellulose material A may be colored and include a pigment layer. Cellulose material A may include a mineral layer, for example, of the kaolin type. Material B and / or solution S comprise: a. At least one casein and / or at least one caseinate; b. Water, and € At least one plasticizer other than b). Casein is a milk protein that is only slightly soluble in water. It is primarily obtained by precipitation by adding an acid (acid casein) or rennet (rennet casein) to milk, or by filtration (miscellar casein). Casein consists of a mixture of alpha-casein, PB-casein, and x-casein with molar masses between 19,000 and 25,000 g / mol. Caseinate, for example, refers to a casein salt whose countercation is selected from the group comprising—preferably—calcium, potassium, ammonium, sodium, and magnesium. According to another embodiment, a) comprises at least one caseinate, for example sodium caseinate, or a mixture of caseinals. According to another embodiment, a) comprises a mixture of casein and at least one caseinate. In this case, the mass ratio between the casein and the caseinate(s) may be between 5 / 95 and 95 / 5, 20 / 80 and 80 / 20 or 40 / 60 and 60 / 40. Material B and / or solution S$ may include gelatin d). Gelatin is a protein with a high glycine and proline content. It is Obtained by partial hydrolysis of collagen, primarily from collagen contained in animal skin and bones, it can be type A (in which case it comes from an acid treatment of collagen) or type B (in which case it comes from a basic treatment of collagen). It can also be obtained by enzymatic treatment of collagen. The gelatin used is preferably unmodified. According to one embodiment of the invention, the gelatin used is commercially available food-grade gelatin or type B; it can be in the form of sheets, powder, or granules. Advantageously, the gelatin used is type B. The ratio of quantities a) : d), when d) is present, may be between 90:10 and 20:80, preferably between 75:25 and 25:75, and preferably between 60:40 and 40:60. According to a particular embodiment, the ratio a) :d) is 50:50. According to a particular embodiment, the ratio a) :d) is between 55:45 and 45:55. The plasticizer c) can be chosen from polyols, glycerol acetates, glycerol propionates and mixtures thereof. Examples of polyols include glycerol, hexanetriol, glycols, including ethylene glycol, and sugars and their derivatives. Examples of sugars include disaccharides, such as maltose, lactose, sucrose, and monosaccharides such as fructose. Among the derivatives of sugars, we can mention their hydrogenated derivatives such as sorbitol, maltitol, mannitol, and xylitol, or even the transformation products of these hydrogenated derivatives such as sorbitan. In one embodiment, the plasticizer c) is selected from glycerol, sorbitol, mannitol, ethylene glycol, and mixtures thereof. Preferably, the plasticizer c) is selected from glycerol, sorbitol, and mixtures thereof. In one embodiment, the plasticizer c) is glycerol. Plasticizer c) may contain residual water. The plasticizer (€) allows the viscosity of the product to be lowered by increasing the mobility of the molecular chains. Advantageously, the plasticizer €) is a hydrophilic plasticizer. Material B and / or solution S may further comprise a hydrophobic agent e). The hydrophobic agent e) may be chosen from: - polycarboxylic acid esters; - carboxylic acids in C3-C33, preferably fatty acids in C4-Czs, and, even more preferably unsaturated fatty acids in Cs-Czg; - and their mixtures. The esters of polycarboxylic acid can be derived from at least one polycarboxylic acid and at least one alcohol, preferably a C1-C1s alcohol. Among the polycarboxylic acids preferably retained in the context of the invention, we can mention citric acid, hydroxycitric acid, tartaric acid, malic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid. Among the preferred alcohols according to the invention, we can mention Cz-Cç alcohols, such as ethanol, n-propanol, iso-propanol, n-butanol and tert-butanol. According to one embodiment, the hydrophobic agent e) is chosen from triethyl citrate, tributyl O-acetyl citrate, tributyl citrate and mixtures thereof. According to one embodiment, the hydrophobic agent e) is a C3-C3 carboxylic acid, preferably a C,-Cx, fatty acid, and even more preferably an unsaturated C5-Czs fatty acid. Among the C,-Cz fatty acids retained within the framework of the invention, we can mention caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and mixtures thereof. Among the particularly interesting Cs-Cas unsaturated fatty acids, we can mention palmitoleic acid, oleic acid, linoleic acid, and their mixtures. Material B and / or solution S may further comprise at least one surfactant f), preferably chosen from among zwitterionic surfactants with an HLB between 2 and 8. Preferred surfactants include lecithin and / or its analogues such as diacetyl phosphonates, and polysorbates. Polysorbates are esters of fatty acids and polyoxyethylene sorbitan. Examples of polysorbates include polysorbate 20, polysorbate 40, polysorbate 60, and polysorbate 80. According to one embodiment, the ratio of the quantities of f) to e) is greater than or equal to 1. For example, this ratio may be between 1.3 and 3; preferably between 1.5 and 2.5. Material B and / or solution S may further comprise a polysaccharide g). Preferably g) is selected from pullulan, starch, alginates, and mixtures thereof. The polysaccharide g) may be a water-soluble polysaccharide. Material B and / or solution S may further comprise a bittering agent h), preferably denatonium benzoate. The bittering agent h) may be selected from denatonium benzoate, denatonium benzoate derivatives, denatonium saccharide, denatonium chloride, sucrose benzoate, quinine, quinine hydrochloride, quinine sulfate, brucine, brucine sulfate, quassia, quassine, naringin, limonine, phenylthiocarbamide, quebracho, sucrose octacetate, quercetin, berberine, and mixtures thereof. According to one embodiment, the material B and / or the solution S comprise also an additive (i) selected from colorants, protein coagulants, anti-caking agents, sliding agents, and mixtures thereof. Examples of coagulants include citric acid and acetic acid. Examples of anti-caking agents include colloidal silica. Examples of sliding agents include polyethylene glycols and fatty-chain compounds, preferably C,-Cas, having an amide ending. In one embodiment, the material B and / or the solution S comprise an additive j) selected from sequestering agents. "Sequestering agent" means, for example, ligands that form chemical complexes with metal ions such as copper, iron, nickel, calcium, and magnesium. Examples of sequestering agents include diammonium citrate, EDTA, phosphates, citric acid, pyrophosphates, and mixtures thereof. The proportions of the different constituents of material B are expressed as a percentage by weight relative to the total weight of material B at room temperature. According to one embodiment, material B comprises between 10 and 80% casein and / or caseinate (a), preferably between 20 and 75%, and, even more preferably, between 25 and 70%. According to one embodiment, material B comprises between 50 and 80% casein and / or caseinate (a), preferably between 52 and 75%, and more preferably between 55 and 70%. According to another embodiment, material B comprises between 10 and 55% casein and / or caseinate (a), preferably between 20 and 50%, preferably between 25 and 40%, and more preferably between 30 and 35%. According to one embodiment, material B comprises between 1 and 55% of gelatin d), preferably between 5 and 50%, preferably between 10 and 40%, and even more preferably between 30 and 35%. According to a particular embodiment, material B comprises between 30 and 35% casein and / or caseinate a), and between 30 and 35% gelatin d). Material B may contain between 5 and 15% water (b), preferably between 7 and 11%. The amount of water may be between 9 and 10%. The water acts as a plasticizer and must be distinguished from the plasticizer (e) that is part of the composition of material B. Material B may comprise c) between 10 and 35% of at least one plasticizer other than c), preferably between 15 and 30%. Material B may comprise between 0.1 and 8% of a hydrophobic agent (e), preferably between 1 and 4%. Advantageously, material B comprises between 0.5 and 6%, preferably between 1 and 3%, of a hydrophobic agent (e). Material B may comprise between 0.5 and 6% of at least one surfactant (f), preferably selected from zwitterionic surfactants with an HLB between 2 and 8. Advantageously, material B may comprise between 1 and 5% of less a surfactant f), preferably between 1.5 and 4.5%, and even more preferably between 2 and 4%. Material B may comprise between 2 and 10% of a polysaccharide (g), preferably (g) is selected from pullulan, starch, alginates, and mixtures thereof. Advantageously, material B comprises between 4 and 8% of a polysaccharide (g). Material B may comprise between 0.001 and 0.5% of a bittering agent h), preferably denatonium benzoate. Advantageously, material B further comprises between 0.05 and 0.15% of a bittering agent h). Material B may comprise between 0.1% and 5% of i). Material B may comprise between 1% and 5% of an additive j) chosen from among the sequestering agents. Material B may be water-soluble and / or biodegradable. Material B may be bio-based. In one embodiment, material B is a thermoplastic material. Material B may be obtained by extrusion, as mentioned in the examples. According to one embodiment, the layer of material B is a layer of film of material B, preferably a layer of thermoplastic, biodegradable, and water-soluble film of material B. Typically, the layer of film of material B has a thickness of between 1 and 150 microns, preferably between 2 and 50 microns, and more preferably between 2.5 and 20 microns. The proportions of the different components of solution S are expressed as percentages by weight relative to the total weight of dry matter in solution S. In one embodiment, solution S comprises between 0.1 and 90% dry matter, preferably between 1 and 50% dry matter, preferably between 5 and 25% dry matter, and more preferably between 10 and 20% dry matter. Solution S can be obtained by dissolving material B in water or by dissolving the individual components in water. According to one embodiment, solution S comprises between 10 and 80% of casein and / or caseinate a), preferably between 20 and 75%, and, even more preferably, between 25 and 70%. According to one embodiment, solution S comprises between 50 and 80% casein and / or caseinate (a), preferably between 52 and 75%, and more preferably between 55 and 70%. According to another embodiment, solution S comprises between 10 and 55% casein and / or caseinate (a), preferably between 20 and 50%, preferably between 25 and 40%, and more preferably between 30 and 35%. According to one embodiment, solution S comprises between 1 and 55% of gelatin d), preferably between 5 and 50%, preferably between 10 and 40%, and even more preferably between 30 and 35%. According to a particular embodiment, solution $ comprises between 30 and 35% of casein and / or caseinate a), and between 30 and 35% gelatin d). Solution S may include €) between 10 and 35% of at least one plasticizer other than c), preferably between 15 and 30%. Solution S may comprise between 0.1 and 8% of a hydrophobic agent (e), preferably between 1 and 4%. Advantageously, solution S comprises between 0.5 and 6%, preferably between 1 and 3%, of a hydrophobic agent (e). Solution S may comprise between 0.5 and 6% of at least one surfactant f), preferably chosen from among zwitterionic surfactants having an HLB between 2 and 8. Advantageously, solution S may comprise between 1 and 5% of at least one surfactant f), preferably between 1.5 and 4.5%, and even more preferably between 2 and 4%. Solution S may comprise between 2 and 10% of a polysaccharide (g), preferably (g) is chosen from pullulan, starch, alginates, and mixtures thereof. Advantageously, solution S comprises between 4 and 8% of a polysaccharide (g). Solution S may comprise between 0.001 and 0.5% of a bittering agent h), preferably denatonium benzoate. Advantageously, solution S further comprises between 0.05 and 0.15% of a bittering agent h). Solution S may comprise between 0.1% and 5% of i). Solution S may comprise between 1% and 5% of an additive j) chosen from among the sequestering agents. Solution S may also contain a preservative and / or a biocide. The concentration of preservative and / or biocide may be between 0.1 and 5%. Packaging made of a multi-layered material This disclosure also relates to packaging comprising a multilayer material. In some cases, the packaging includes layers other than the multilayer material; in other cases, the packaging consists solely of the multilayer material. This disclosure also relates to the use of a multi-layer material for packaging various products (pharmaceutical, food, chemical, cosmetic, etc.). This disclosure also relates to a product packaged in packaging comprising a multi-layered material. The product can be in solid, liquid, or gel form. The packaged product can be any object; for example, it could be a mechanical part, a DIY item, a gardening tool, a magazine, a newspaper, or disposable tableware. The packaged product can, for example, be chosen from pharmaceutical, food, chemical, and cosmetic products. According to one embodiment, the packaged product is a food product, such as meat, fish, vegetables, fruit, pastries, viennoiseries, chocolate, confectionery, food additives, ingredients, dry preparations, food powders, prepared dishes. In one embodiment, the packaged product is a cosmetic product. In another embodiment, the packaged product is a detergent. Detergents can be in liquid or powder form, compact or loose. For example, a detergent tablet might be one. Examples of detergent tablets include dishwasher tablets and laundry detergent tablets. Liquid detergents, such as laundry detergent, are another option. (The last sentence appears to be unrelated and possibly a separate entry: "Process for manufacturing a multilayer material"] The multilayer material can be manufactured by lamination, coating, bonding, co-extrusion or extrusion coating processes well known to those skilled in the art. This disclosure also relates to a method for manufacturing a multilayer material, characterized in that it is carried out - either by coating a layer of cellulosic material A with a solution S comprising: a At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer different from b); - either by assembling a layer of cellulosic material A and a layer of material B comprising: a At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer other than b), possibly by means of a binder, the assembly being preferably carried out by lamination or bonding. In one embodiment, the multilayer material is manufactured by coating. In this case, the cellulose material layer A is coated with a solution S. This can be done using a coating material well known to those skilled in the art. After coating, the coated cellulose material A can be dried, for example in an oven, to obtain the multilayer material. According to another embodiment, the manufacture of the multilayer material is carried out by assembling a layer of cellulosic material A and a layer of material B. In this case, the assembly can be carried out by complexing or lamination. Lamination can be performed cold or hot. In the case of lamination with In the case of cold lamination, a binder can be used. In the case of hot lamination, this step can be carried out without a binder. Complexation can be achieved by a laminating, co-extrusion or extrusion coating step, with or without a binder. When a binder is used, the assembly can, for example, be carried out by coating one face of one of the materials A or B with a binder, then bringing the two materials into contact so that the binder is between them. This assembly can be carried out using a calender. EXAMPLES In the examples below, two types of cellulosic materials (papers) were coated with a sodium caseinate and glycerol solution, prepared from thermoplastic granules, to create a multilayer material according to the invention. Unless otherwise stated, throughout this document, percentages are expressed as weight percentages. The cellulosic materials used are as follows: - Algro Sol PCC 90g / m² paper from Sappi, Kraft paper coated with kaolin on one side, 21*35cm format, coating on the glossy side. - Terrana 85g / m2 paper from Gascogne Papier, natural kraft paper, rubbed on one side, coated on the rubbed side, Size 21*35cm The thermoplastic granules used for coating were prepared by extrusion from sodium caseinate. The extruder used was a Clextral® BC 21 twin-screw co-rotating extruder, with a diameter of 25 mm, a center distance of 21 mm, and a length of 900 mm. This extruder has at least 4 zones: an initial introductory zone, a second introductory zone, a third degassing zone, and a fourth sector zone, The rotation speed of the twin screws is between 175 and 320 rpm and the temperatures of the different zones are between 30 and 120°C. The first zone of the extruder is a powder introduction zone: caseinate and lecithin. Liquids are introduced into the second zone. The extruder also includes an open-air degassing zone and a final zone consisting of a cylindrical rod die with a diameter of 4 mm. The screw profile is as follows: 750 mm of direct pitch screw, 50 mm of mixing screw, 100 mm of reverse pitch screw. After exiting the extruder, the rush is dried and fed into a granulator to produce granules 2 to 3 mm in diameter. The final composition of the granules is the next: 63% sodium caseinate, 23.5% glycerol, 10% water, 2.3% soy lecithin, and 1.1% oleic acid. Coating of papers Dissolving the thermoplastic granules in water under agitation, to obtain a solution of 11%, 18% or 19% dry matter. The papers were coated with the solution using laboratory coating equipment, an Elcometer which allows the translation of a threaded rod to spread and apply the solution to the surface of the paper. Two coating passes were made on the same side of each paper to obtain a coating weight of 9 or 14 g / m². The results are presented in Table 1. [Table 1] Total Coating Weight | Substrate %MS Solution 9 g / m² Gascogne 11% 14 g / m² Gascogne 19% 9 g / m² Sappi 18% 14 g / m² Sappi 18% The coated paper sheets are then oven-dried at 55°C and then under a dermi-lune dryer at 80°C. They are then placed under a heavy metal plate. Characterization of the coated papers obtained Physical properties Weight and thickness The characterization of uncoated and coated backing papers was carried out under standardized conditions at 23°C and 50% RH (NF EN 20 187, 1993). Basis weight was measured according to the method described in standard NF EN ISO 536, 2012, and thickness according to the method described in standard NF EN ISO 534, 2011. The results obtained are consistent with the expected values ​​and correspond to the different coatings applied to the two papers. Adhesion Testing Method FINAT Good adhesion between the material layer B, containing sodium caseinate, and the paper layer A, made of cellulose material, is required. The adhesion of the coated layer to the paper was tested according to the Finat 1 method: To perform the test under optimal conditions, a primer must be applied to the samples, either manually or with tape, to separate the coating from the substrate and thus allow the layer to be peeled off. However, it was not possible to create this primer because the adhesion between the coated layer and the paper substrate was too strong. Adhesion was then tested using the Finat 3 method: In this method, the coated substrate is adhered to a board using tape. The test specimens prepared in this way are made according to the Finat 3 method, namely: the board / tape / coated paper assembly is held for 20 hours at 23°C under a pressure of 6.86 kPa (70 g / m²). As in the Finat 1 method, no delamination between the coated layer and the paper substrate was observed. In fact, the delamination occurred at the tape joint. These tests show that the surface coating adheres very well to the paper substrate, to the point that it is not possible to measure the peel strength. The adhesion of the coated layer to the various substrates is very good, regardless of the coating weight applied (9 or 14 g / m²). Barrier properties Barri isses: Cobb index method in oil The Cobb index measurement is performed on a 25 cm² area, and the duration is set here at 60 seconds. ISIO 4 oil colored with Sudan III red is used, which allows for the visualization of any defects. A method derived from the SCAN-P 37 standard is employed. The Cobb index measurement determines the amount of oil that the surface of paper or cardboard can absorb during a specific time, in this case, 60 seconds. The lowest possible Cobb index is desired. Measurements were taken on 5 different samples. The mean and standard deviation were then calculated. Measurements were taken at 23°C / 50% RH after the samples had been incubated under these conditions for at least 12 hours. The results are presented in Table 2. [Tables 2] 0.3 Very light dots 0.4 No dots 0.2 | No dots Sample Cobb Index - [Standard Deviation Observations Gascogne Paper 29.7 3.9 Perforation Gascogne Paper + coating [11 0.6 [No dots of 9 g / m²? Gascogne Paper + coating |13 Jos [No dots of 14 g / m²? Sappi 10.1 0.3 Very slight dots Sappi + coating 9 g / m² 0.7 0.4 No dots of Sappi + coating 14 µm? 0.8 0.2 |No dots of These results show that the multilayer materials according to the invention have a much lower Cobb index than uncoated paper supports, which reflects an improvement in grease barrier properties. Oxygen barrier: Characterization OTR measurement at 23°C - 50% RH according to ASTM F1927 Oxygen levels were measured using a Presens instrument according to ASTM F1927. Measurements were taken at the temperature and humidity of the conditioned room, 23°C / 50% RH. Measurements were duplicated on four different samples. The results are presented in Table 3. [Tables 3] Measured value > 1,000,000 P 30,000 Sample Value My Gascogne Paper > 1,000,000 Gascogne Paper + 9 g / m² coating? 30,000 Gascogne Paper + 14 g / m² coating? > 18,000 Sappi > 25,000 Sappi + 9 g / m² coating 69 / 62 Sappi + 14 g / m² coating 0 / 0 These results show that the multilayer materials according to the invention have a much lower oxygen permeability than uncoated paper supports, which reflects an improvement in oxygen barrier properties. Recyclability of multilayer materials according to the invention The recyclability of the multilayer materials according to the invention has been determined. The recyclability of packaging is assessed in accordance with Directive 2018 / 852 / EU of 30 May 2018 (amending Directive 94 / 62 / EC). The recyclability of packaging comes down to verifying two criteria so that it can be recovered in the paper recycling industry: - the packaging must have a paperboard-based structure comprising at least 50% by weight of paperboard material, and - The packaging must be designed with materials or combinations of materials that are compatible with known, relevant, and industrially available recycling technologies. It must not negatively affect recycling processes. All multilayer materials prepared according to the invention contain at least 50% by weight of paper / cardboard material. The first condition is therefore met. A recycling test was then carried out with the multilayer materials prepared according to the invention in order to evaluate the impact of the presence of the material layer B comprising sodium caseinate. The different steps carried out are presented below. 4 ion (ISO 5263-1* standard) The pulping operation consists of separating the cellulosic fibers to make the fibrous suspension pumpable for classification using a laboratory pulper. For the purposes of the test, and more specifically for resuspension, we manually tore the 60g sample into pieces of approximately 3 x 3 cm to make it compatible with the dimensions of the laboratory pulper. The prepared raw material is then resuspended under the following conditions: - Temperature*: 40 °C - Concentration: 3% (by weight) - Duration: 15 min - Condition: neutral These conditions are representative of the conditions applied industrially (* exception: temperature of 40°C to simulate water temperatures in industrial recycling processes) OL ion di ion fil dési j After 15 minutes of disintegration, the disintegrated raw material (called a paste or fibrous suspension) is visually observed to check two points: - The individualization of fibers indicates good defibration, and therefore sufficient pulping time. The 15 minutes can be extended if necessary. - The color of the pulping water to check whether or not the packaging has disgorged (color, ink and / or varnish). sp- Classification or elimination of non-fibrous unwanted materials (TAPPI-ANSI T275 18 standard): The paste resulting from the disintegration of the sample to be tested is then collected and sorted using two cascaded Somerville laboratory sorting machines. The first machine is equipped with a 15 / 100 mm slotted sieve, and the second with a 10 / 100 mm sieve. The acceptable paste passes through the slots of the sorters, while undesirable elements (such as pieces of plastic) remain on the surface of the sorting sieve. The first sorter retains large contaminants, and the second retains any residual contaminants. appearance At the exit of the pulping and 10 / 100 mm classification stages, laboratory sheets (called formettes) are produced according to the Rapid-Käthen method (ISO 5269-2: 2004 Standard Pastes — Preparation of laboratory sheets) The results obtained are presented in Table 4 below. [Tables 4] |Sappi Paper Sample Gascogne Paper Sappi Gascogne | Gascogne | Gascogne Paper+ | Paper Paper+ | Paper+ coating coating | coating 14 g / m²? 9 g / m²? 14 g / m²? |15 mins [15 mins |15 mins |15 mins |15 mins [No [No [No [No Aspect Aspect Aspect Aspect Visual appearance ok |visualok |visualok |visualok |visual ok Jox | Jox — jox Jox — | ox Pulping Stage Time |15 min |15 min [is min [15 min |15 min |15 min Pulping Forms |Appearance Appearance Appearance Appearance Appearance of visual appearance ok |visual ok |visual ok |visual ok |visual ok |visual ok |visual ok Color of the J OK OK OK OK Jos OK Sorting Stage Rejects, 2.932 g 3.316 g 4.060 g 0.209 g 0.092 g 0.140 g 15 / 100 5.20 % 5.88 % 7.20 % 0.16 % 0.37% 0.25 % Rejects, 0.846 g 0.837 g 0.760 g 2.205 g 4.616 g 6.060 g 10 / 100 1.58 % 1.58 % 1.45% 3.92% 8.21% 10.77% Glue |No No No No No No 0.15 mm grid Glue to the [No |No [No |No [No [No 0.10 mm grid Forms |Appearance Appearance Appearance Appearance Appearance of visual appearance ok [visual ok |visual ok |visual ok |visual ok |visual ok |visual ok (Som-| merville 10 / 100mm output) pre OK ok OK ok OK OK OK ê These results show: - that good fiber individualization is obtained during pulping - that correct rejection rates are obtained during classification, these rates are acceptable for recyclability. - that the molds coming out of the pulper or grading machine have a completely satisfactory visual appearance. These results show that the multilayer materials according to the invention meet the various recyclability criteria of packaging as defined in Directive 2018 / 852 / EU of 30 May 2018. The presence of layer B of material comprising sodium caseinate and glycerol, on a layer A of cellulosic material does not affect the recyclability of this cellulosic material.

Claims

Demands

1. Multilayer material comprising: 1) At least one layer of cellulosic material A, and ii) At least one layer of material B comprising: a. At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer different from b).

2. Multilayer material according to claim 1, characterized in that the material B further comprises gelatin d).

3. Multilayer material according to claim 1 or 2, characterized in that that material B also comprises a hydrophobic agent e), of preference chosen from: - polycarboxylic acid esters; - C-C73 carboxylic acids, preferably C-C fatty acids; - Cases, and, even more preferentially, unsaturated fatty acids in Ce-Czs - and their mixtures.

4. Multilayer material according to any one of the preceding claims, ca- characterized in that material B further comprises at least one ten- ioactive (f), preferably selected from zwitterionic surfactants whose HLB is between 2 and 8.

5. Multilayer material according to any one of the preceding claims, ca- characterized in that the plasticizer (€) of material B is chosen from among the polyols, glyceryl acetates, glyceryl propionates, and their mixtures, preferably c) is chosen from glycerol, sorbitol, and their mixtures.

6. Multilayer material according to any one of the preceding claims, ca- characterized in that material B comprises between 10 and 80% casein and / or caseinate a), preferably between 20 and 75%, and, more preferably- still very much, between 25 and 70%.

7. Multilayer material according to any one of the preceding claims, ca- characterized in that the cellulosic material A is chosen from among the papers and cardboard.

8. Multilayer material according to any one of the preceding claims, ca- characterized in that the material layer B is a film layer of material B.

9. Multilayer material obtained: - either by coating a layer of cellulosic material A with a Solution S includes: a. At least one casein and / or at least one caseinate; b. Water, and c At least one plasticizer different from b); - either by assembling a layer of cellulosic material A and a layer of material B comprising: a. At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer other than b), possibly using a binder, the assembly preferably done by complexing or lamination.

10. Packaging characterized in that it comprises a multilayer material according to one of claims 1 to 7.

11. Product characterized in that it is packaged in a manner according to the re- demand 10.

12. Product according to claim 11, characterized in that it is a food product.

13. A method for manufacturing a multilayer material, characterized in that that it is carried out - either by coating a layer of cellulosic material A with a Solution S includes: a. At least one casein and / or at least one caseinate; b. Water, and c At least one plasticizer different from b); - either by assembling a layer of cellulosic material A and a layer of material B comprising: a. At least one casein and / or at least one caseinate; b. Water, and c. At least one plasticizer other than b), possibly by means of a binder, the assembly being preferably carried out by lamination or bonding.