BR112020024150B1 - MULTILAYER STRUCTURE - Google Patents

Abstract

ARTICLE IN THE FORM OF A MULTILAYER STRUCTURE. The invention provides highly stable and versatile multilayer structure or articles based on cellulose nanomaterials, adapted and processed for a variety of applications, such as superior materials in the food packaging industry.

Description

FIELD OF TECHNIQUE

[001] The invention generally relates to multilayer articles and uses thereof.

BACKGROUND

[002] Cellulose nanocrystals (CNC) are one of the known forms of cellulose, the main component of cell walls of trees and plants. CNC can be present as liquid crystal solution in water and is known to self-assemble into macroscale ordered films with nanoscale thicknesses.

[003] Nanometric crystals have interesting size-dependent structural and optical properties. The ability to perform with processing variables provides the ability to control the structure, composition, size and level of dispersion of such nano crystals.

BACKGROUND OF THE TECHNIQUE

[004] (1) WO2017/046798

[005] (2) WO2017/199252

[006] (3) WO2013/132491

[007] (4) US2005/0042443

[008] (5) US9,227,381

[009] (6) US5,547,764

GENERAL DESCRIPTION

[0010] The inventors of the technology disclosed herein have developed highly stable and versatile multilayer structures or articles based on cellulose nanomaterials, such as cellulose nanocrystals (CNC), which can be adapted and processed for a variety of applications and which are materials superior to aluminum foils used, for example, in the food packaging industry, as well as in other polymer-based structures and articles, and which exhibit superior barrier properties to gases, organic solvents, oils and other agents.

[0011] As demonstrated in the present document, the articles of the present invention, which are multilayer structures that can be used in a variety of products and applications, have demonstrated

[0012] superiority also in relation to existing and known products, built in multilayers of cellulose nanomaterials and polymers, such as polyvinyl alcohol (PVOH).

[0013] The superiority of the multilayer structures of the invention is, among others, based on the presence of a layer of a mixture of CNC and PVOH (CNC-PVOH mixture). Superiority is reflected in:

[0014] (1) a grease barrier of 12, as determined using TAPPI T 559 standard (approved by the Physical Properties Committee of the Process and Product Quality Division);

[0015] (2) an oxygen transmittance ratio (OTR) between 0.01 and 15, or between 0.01 and 1, or between 0.01 and 5, or between 1 and 10, or between 1 and 5 or generally values below 1 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C; and/or

[0016] (3) a water vapor transmittance ratio (WVTR) between 0.01 and 20, or between 0.01 and 1, or between 0.01 and 5, or between 1 and 10, or between 1 and 5, or between 5 and 10, or generally values below 1 g/m2-day, when measured at 90% RH, at 38 °C.

[0017] These properties support highly unique and useful articles that are in no way comparable to similar articles of the art. For example, a CNC-PVOH blend film shows better mechanical and barrier properties compared to pure PVOH film and compared to a CNC film. In a multilayer structure of the invention, the advantage of the CNC-PVOH layer, compared to the pure PVOH layer, is further increased, by the formation of better interactions between the CNC-PVOH layer and its adjacent layers, which increases the adhesion between layers, and improve barrier properties and mechanical properties compared to multilayer structures comprising pure PVOH. Where PVOH performs well as a barrier, CNC-PVOH exceeds its performance and exhibits excellent to superior properties, and inclusion in a multilayer structure further improves performance.

[0018] In contrast to multilayer structures in the art, such as those disclosed for example in document number US20050042443, at least one PVOH coating layer and a total coating weight of at least 7 g/m2 are required to provide a TAPPI standard rating T 559 of 12, when coated on paper substrates. A CNC-PVOH coating resulted in a TAPPI T 559 standard rating of 12 when a coating weight of just 2.5 g/m2 was used, thus proving that the performance of such multilayer structures of the invention is beneficial compared to e.g. , insulated PVOH coatings.

[0019] The oxygen barrier properties of multilayer structures comprising CNC-PVOH blends over PVOH-based layers have also been demonstrated. In Kraft papers and boards, oxygen transmission rates of PVOH structures were measured to be 1.5 to 2 times higher (lower barrier) than for CNC-PVOH structures, for the same weight, when they did not consist of layers. plastic. Structures with plastic layers and PVOH barrier layer showed OTR values 2 to 20 times higher (lower barrier). Kraft paper coated with a 5 g/m2 PVOH layer resulted in an OTR (at 80% RH) of 20 to 30 cm3/m2-day compared to an OTR of 8 to 15 cm3/m2-day for a CNC-PVOH of 5 g/m2 under the same conditions. PP/cardboard/PVOH (5 g/m2)/PP scaffolds resulted in an OTR (at 80% RH) of 10 to 20 cm3/m2-day as compared to an OTR of 0.5 to 5 cm3/m2-day for the same structures with a 5 g/m2 CNC-PVOH layer under the same conditions.

[0020] As a person skilled in the art would appreciate, OTR values are typically obtained and reported for multilayer structures tested at 0% relative humidity (RH). In practical terms, this value has no meaning in the production of a structure for packaging purposes, since the terms of use of structures always involve RH levels always greater than 0%. Furthermore, the RH levels at which barrier products are used in industry is 80% RH. Many barrier layers, including PVOH or PVOH-based barrier layers, show OTR stability when measured at -50% RH, but increase exponentially in OTR values as RH levels increase. Thus, a prior art, such as document number US 9,227,381, in which a PVOH-based layer leads to OTR values of 4 to 12 cm3/m2-day at 0% RH, does not provide any indication nor allow the predication of barrier capabilities at 80% RH. In contrast, OTR values measured for structures with a CNC-PVOH layer are less than 1 cm3/m2-day under the same conditions and are therefore comparable to structures containing metallized layers, described in the art.

[0021] In document number US 5,547,764, PVOH and mixtures of PVOH grades were coated on polypropylene (PP) and tested for OTR at 0% and 75% RH. The best OTR value revealed was > 20.15 cm3/m2-day at 75% RH, which is greater than the OTR value obtained for a PP layer coated with a CNC-PVOH layer of the invention, which in comparison demonstrated, the 80% RH, a value of < 15 cm3/m2-day.

[0022] The adhesion advantages of a CNC-PVOH barrier layer, used according to the invention, over a PVOH barrier layer, were also demonstrated in the present document. A multilayer structure in which the barrier layer is in contact, on one or both sides, with a plastic layer, needs to involve strong adhesion between the barrier and the plastic layers. Poor adhesion is expected to lead to detachment and separation of layers during the production of a final product, such as packaging, or when the product is used. As demonstrated, a multilayer structure in which PVOH was used instead of a CNC-PVOH layer, in contact with a plastic layer, resulted in a 3 to 10 times weaker adhesion interaction between the barrier layer and the barrier layer. of plastic compared to CNC-PVOH layer adhesion for the same plastic layer (0.5 N/15 mm for PVOH compared to 1.5 to 5 N/15 mm for CNC-PVOH).

[0023] The articles of the invention are free of metallic layers and achieve their stability, durability and improved properties, even in the absence of such layers. In fact, the articles of the invention are free from any metallic nanoparticles and are generally free from any metal-containing layer and are therefore suitable for a wide variety of applications, including packaging materials for food, beverages, consumer goods and products. pharmacists. These articles can be adapted or pre-structured according to one or more end uses or applications. For example, an article according to the invention can be specifically adapted as a dry food packaging material or as a liquid food packaging material. Additionally, the articles of the invention are fully biodegradable or comprise at least one layer that is biodegradable or are generally degradable.

[0024] In a first aspect, the invention provides an article in the form of a multilayer structure (which may be in the form of a substantially two-dimensional sheet or a three-dimensional article or product) comprising a plurality of layers of material, e.g. three or more layers of material, at least one of said three or more layers of material comprising a cellulose nanomaterial selected from cellulose nanocrystals (CNC), microfibrillated cellulose (MFC), a combination of CNC and nanofibrillar cellulose (NFC) , a combination of CNC and MFC, or a blend of CNC with at least one additive, for example, a polymer that is water-soluble or water-dispersible (such as hydroxyl- or carboxyl-rich polymers).

[0025] In some embodiments, the cellulose nanomaterial is CNC or not microfibrillated cellulose (MFC).

[0026] In some embodiments, each of the three or more (at least three) layers of material is biodegradable or generally degradable and is free of metallic materials or components.

[0027] In some embodiments, the multilayer article comprises a substrate, a cellulose nanomaterial, for example, a CNC-based layer (such as a mixture of CNC and PCOH), and a cover layer, such that the nanomaterial layer of cellulose forms an interface between the substrate and the cover layer. Wherein the multilayer structure comprises more than three layers; that is, a substrate, a cellulose nanomaterial, a cover layer, and another layer interposed between the substrate and the cover layers, the cellulose nanomaterial layer can be positioned anywhere relative to the other layer (e.g., the cellulose nanomaterial layer does not need to be positioned equidistant from the substrate and the cover layers).

[0028] In some embodiments, the multilayer article consists of a substrate, a CNC-based layer, and a cover layer, such that the CNC-based layer forms an interface between the substrate and the cover layer.

[0029] In some embodiments, the substrate and the covering layer are the same. In some embodiments, the substrate and the cover layer are different.

[0030] As used herein, a "layer of material" is any layer comprising or consisting of the indicated material, which exhibits a uniform or homogeneous distribution of the material throughout the layer. The material layer may be composed of a single layer or composed of a plurality of layers, each of the plurality of layers comprising the same material. Since the two layers are distinct in their composition, they can be considered as two layers of different materials. For example, a layer of material comprising at least one cellulose nanomaterial may be structured from multiple layers of the same material, wherein the multiple layers are used to, for example, increase the thickness of the layer. Where two different cellulose materials are used as a mixture, as defined, this mixture can be used to form a layer of material. However, as defined herein, where the two materials are not in the form of a blend, each would form a different layer of the multilayer structure.

[0031] Each layer of material has a thickness ranging from 100 nm to 20 μm. In some embodiments, the thickness is between 100 and 900 nm, between 900 nm and 20 μm, between 1,000 nm and 20 μm, between 1 μm and 20 μm, or between 1 μm and 10 μm.

[0032] Each layer of material of the multilayer structure is adhesively connected, associated or fixed to one or two adjacent (neighboring) layers. The term "adhesive connection/association/attachment" or any linguistic variation thereof, refers to the fact that any two adjacent layers in multilayers are closely associated with each other through the use of an adhesive layer or pretreatment of one or both of them. the layers to be associated to enable effective association. Such pretreatment may include heat treatment, a plasma treatment, corona, flame, primer application or any other known pretreatment method. Where an adhesive layer is used, it may be an interface layer between any two layers of material with a thickness between 100 nm and 3 μm or may be considered an independent layer of the multilayers, as may be the case. Suitable adhesives or primer materials are described below.

[0033] In some embodiments, the association or adhesion between the two layers does not require the use of an adhesive or a primary formulation, nor any pretreatment of any of the layers to be associated. In some cases, one layer, e.g., a CNC-PVOH blend layer, as described herein, is formed over another, e.g., a paper-based substrate, without the need to use an adhesive, a formulation primary or any pre-treatment.

[0034] In another aspect, the invention provides an article in the form of a multilayer structure comprising a plurality of layers of material (three or more layers), at least one of said layers of material being a substrate layer and at least one of said material layers is a CNC-PVOH blend layer.

[0035] In some embodiments, the multilayer structure is characterized by one or more of the following:

[0036] (1) a grease barrier of 12, as determined using TAPPI T 559 standard (approved by the Physical Properties Committee of the Process and Product Quality Division);

[0037] (2) an oxygen transmittance ratio (OTR) between 0.01 and 15, or between 0.01 and 1, or between 0.01 and 5, or between 1 and 10, or between 1 and 5 or generally values below 1, when measured at 80% relative humidity (RH), at 23 °C; and/or

[0038] (3) a water vapor transmittance ratio (WVTR) between 0.01 and 20, or between 0.01 and 1, or between 0.01 and 5, or between 1 and 10, or between 1 and 5, or between 5 and 10, or generally values below 1, when measured at 90% RH, at 38 °C.

[0039] In another aspect, the invention provides an article in the form of a multilayer structure comprising a plurality of layers of material (three or more layers), at least one of said layers of material being a substrate layer and at least one of said layers of material is a CNC-PVOH blend layer, wherein the article has a grease barrier value of 12, as determined using the TAPPI T 559 standard (approved by the Physical Properties Committee of the Process Quality Division and Product).

[0040] In another aspect, the invention provides an article in the form of a multilayer structure comprising a plurality of layers of material (three or more layers), at least one of said layers of material being a substrate layer and at least one of said material layers is a CNC-PVOH blend layer, wherein the article has an oxygen transmittance ratio (OTR) between 0.01 and 15, or between 0.01 and 1, or between 0.01 and 5 , or between 1 and 10, or between 1 and 5 or generally values below 1, when measured at 80% relative humidity (RH), at 23 °C.

[0041] In another aspect, the invention provides an article in the form of a multilayer structure comprising a plurality of layers of material (three or more layers), at least one of said layers of material being a substrate layer and at least one of said material layers is a CNC-PVOH blend layer, wherein the article has a water vapor transmittance ratio (WVTR) between 0.01 and 20, or between 0.01 and 1, or between 0.01 and 5, or between 1 and 10, or between 1 and 5, or between 5 and 10, or generally values below 1, when measured at 90% RH, at 38 °C.

[0042] As used herein, the term "blend" refers to a mixture of any two or more components, as indicated, that forms a layer of the invention. A "CNC-PVOH blend" layer, for example, refers to a layer of material comprising a mixture of CNC and PVOH, in any material ratio. Typically, this layer of material consists of mixed materials; namely, the mixture from which the layer is formed consists of only two (or more) materials. In some embodiments, the blend may comprise one or more additives or other materials. Thus, in some embodiments, a layer of CNC-PVOH material consists of CNC and PVOH. In some embodiments, a CNC-PVOH layer comprising a mixture of CNC and PVOH is provided.

[0043] A mixture of CNC and PVOH is a mixture of the two components in a ratio between 0.001:1 and 1:0.001 (CNC to PVOH). In some embodiments, the ratio is 0.001:1, 0.01:1, 0.1:1, 1:1, 1:0.1, 1:0.01, 1:0.001 w/w, CNCPVOH.

[0044] In some embodiments, the ratio is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20 p/w, CNCPVOH.

[0045] In some embodiments, in a mixture of CNC and PVOH, the amount of CNC is between 1 and 99% of the CNC+PVOH weight. In some embodiments, the amount of CNC in the CNC+PVOH combination is between 1 and 99%, 1 and 95%, 1 and 90%, 1 and 85%, 1 and 80%, 1 and 75%, 1 and 70%, 1 and 65%, 1 and 60%, 1 and 55%, 1 and 50%, 1 and 45%, 1 and 40%, 1 and 35%, 1 and 30%, 1 and 25%, 1 and 20%, 1 and 15%, 1 and 10%, 1 and 5%, 10 and 99%, 15 and 99%, 20 and 99%, 25 and 99%, 30 and 99%, 35 and 99%, 40 and 99%, 45 and 99%, 50 and 99%, 55 and 99%, 60 and 99%, 65 and 99%, 70 and 99%, 75 and 99%, 80 and 99%, 85 and 99%, 90 and 99%, 10 and 50%, 15 and 50%, 20 and 50%, 25 and 50%, 30 and 50%, 35 and 50%, or between 40 and 50%, p/w.

[0046] In some embodiments, each of the plurality of material layers is biodegradable and does not contain metallic materials or components. In some embodiments, the substrate layer is biodegradable and in other embodiments, the CNC-PVOH layer is biodegradable.

[0047] In some embodiments, the article has a layered structure of the form ABC, wherein each of A, B, and C is one or more layers of material, as depicted in Figure 1 for a bilayer structure, wherein: A is a substrate comprising or consisting of a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, e.g., a cardboard, a nanocellulose film (i.e. , any of the cellulose nanomaterials, as defined herein), nanocellulose/polymer film (i.e., any of the cellulose nanomaterials, as defined herein, when coated or associated on one or both of its faces with a polymeric material), a fabric material, a porous material or a membrane material; and others; B is a cellulose nanomaterial as selected herein, for example, a CNC-based material comprising CNC or consisting of CNC, or CNC-PVOH blend; C is a cover layer comprising or consisting of a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, e.g., a cardboard, a nanocellulose film , nanocellulose/polymer film, a fabric material, a porous material or a membrane material.

[0048] In some embodiments, each of the material layers A, B and C is free of metallic materials or components.

[0049] In some embodiments, layer A and/or C may be independently selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, e.g. cardboard, a nanocellulose film, nanocellulose/polymer film, a fabric material, a porous material and a membrane material.

[0050] The "polymeric material", when used as an independent layer or as a coating layer of a paper-based material or a nanocellulose material or as an additive to any of the materials constructing any of the layers, can be a material belonging to any known polymeric material or resin, such as thermoplastic polymers and thermosetting polymers. The polymer may be selected from such polymers as polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, chloride of polyvinylidene, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate. In some embodiments, the polymeric material is polyester (which can be selected from thermosets and thermoplastics).

[0051] In some embodiments, the polymer is selected from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate or any mixture of two or more of them.

[0052] As used herein, "paper or paper-based material" is a material known in the art. The paper or paper-based material may be used as such or may be used coated with a polymer on one or both sides. In some embodiments, this paper-coated material is cardboard. In some embodiments, the paper is Kraft paper. As known in the art, Kraft paper is paper or cardboard (cardboard) produced from chemical pulp produced in the Kraft process, as known in the art. The paper is a porous paper with high elasticity and high tear resistance, designed for packaging products with high demands on strength and durability. Thus, paper can additionally be selected from paper-based packaging materials.

[0053] In some embodiments, the paper is selected from bank paper, banana paper, craft paper, book paper, coated paper products, cardstock, sugar paper, cotton paper, vulcanized fiber paper, for inkjet, Kraft paper, bag Kraft paper, laid paper, leather paper, mummy paper, oak tag paper, sand paper, Tyvek paper, wallpaper, Washi paper, waterproof paper , wax paper, tissue paper, rice paper and others.

[0054] As is known in the art, commercial papers or paper-based products of any type described above may contain additives such as clays, calcium carbonate, latex, etc., which are added to the paper in its production process.

[0055] “Fabric material” is any material known in the art that is typically a flexible material constructed from a network of natural or artificial fiber materials. The fabric can be any textile, natural fabric, synthetic fabric, mesh, woven material, non-woven material or mesh from a material selected from cellulose, viscose, glass fibers, carbon fibers and synthetic fibers. In some embodiments, the fabric may be in the form of a porous material or a membrane, selected as indicated.

[0056] The “porous material” or “membrane material” is generally a material that contains pores that can retain or contain a solid, liquid or gaseous material. In some embodiments, the pores are empty spaces, namely, void of any material. In some embodiments, the porous material acts as a membrane, namely as a selective barrier with a degree of selectivity dependent on the membrane pore size. In some embodiments, the membrane may be fabric or paper based.

[0057] Each of layers A and C, independently of each other, may additionally or alternatively be coated or produced from a polymeric material which is known as a varnish material. As known in the art, such varnishes are hydrophobic materials which themselves can act as water resistant layers, water vapor barriers, or provide mechanical protection to any layer with which they are associated, e.g., layer B, or any layers A and C as defined in this document. Varnish layers, either directly on the B layer or on one or both of the A or C layers can also be provided to achieve printability. The varnish material or composition can be obtained commercially available or can be adapted for the particular purpose. The varnish material can be selected from compositions containing a polymer selected from polyurethane, acrylic, epoxy, polyester; resins such as phenolic resin, alkyd resin, polyurethane resin; latex, such as styrene, styrene-butadiene, natural latex; and oils such as linseed oil, walnut oil, tung oil and soybean oil.

[0058] In some embodiments, neither the substrate A nor the cover layer C is a nanocellulose film nor comprises such a material.

[0059] It should be noted that the terms “substrate” and “cover layer” should not be taken to suggest or allude to any directionality to the articles of the invention. In other words, the term “substrate” need not be the lowest layer or the layer from which the manufacture of the article begins. Likewise, the term "cover layer" should not be construed as the uppermost layer nor the layer that caps, surrounds or covers the remaining layers or features of the multilayer structure. .

[0060] As noted herein, layer B comprises or consists of a cellulose nanomaterial, such as a mixture of CNC and NFC. In some embodiments, layer B is NFC-free.

[0061] Cellulose nanocrystals (CNC) or nanocrystalline cellulose (NCC) are fibers produced from cellulose, where the CNC are normally single crystals of high purity. They constitute a generic class of materials with mechanical resistances equivalent to the bonding forces of adjacent atoms. The resulting highly ordered structure produces not only exceptionally high resistances, but also significant changes in thermal, electrical, optical, magnetic, ferromagnetic, dielectric, conductive and even superconductive properties. The tensile strength properties of CNC are far superior to those of current high-volume reinforcements and allow processing of the highest composite strengths achievable.

[0062] CNC can be produced from cellulose or any material containing cellulose or fibrillated cellulose by means known in the art, for example, in document numbers WO 2012/014213, WO 2015/114630, and in US applications derived therefrom , each of which is incorporated herein by reference.

[0063] As known in the art, cellulose nanofibrils (CNF or NFC) are cellulosic materials composed of at least one primary fibril, which contains crystalline and amorphous regions, with aspect ratios generally greater than 50. Their length is 0.1 to 5 μm and its diameter is 5 to 60 nm. Likewise, cellulose microfibrils (CMF or MFC) are cellulosic materials that contain crystalline and amorphous regions, with aspect ratios generally greater than 50. Their length is a few micrometers and their diameter is greater than 100 nm. CMF may contain some fraction of CNF.

[0064] In some embodiments, the cellulose nanomaterial is characterized by having at least 50 percent crystallinity. In some embodiments, the cellulose nanomaterial is monocrystalline. In some embodiments, the cellulose nanomaterial is a high purity monocrystalline material.

[0065] In some embodiments, the nanocrystals of the nanomaterial have a length of at least about 50 nm. In other embodiments, they are at least about 100 nm long or at most 1,000 nm long. In other embodiments, the nanocrystals are between about 100 nm and 1,000 nm in length, 100 nm and 900 nm in length, 100 nm and 600 nm in length, or between 100 nm and 500 nm in length.

[0066] In some embodiments, the nanocrystals are between about 10 nm and 100 nm in length, 100 nm and 1,000 nm, 100 nm and 900 nm, 100 nm and 800 nm, 100 nm and 600 nm, 100 nm and 500 nm , 100 nm and 400 nm, 100 nm and 300 nm, or between about 100 nm and 200 nm in length.

[0067] Nanocrystals can be selected to have an average aspect ratio (length to diameter ratio) of 10 or more. In some embodiments, the average aspect ratio is between 10 and 100, or between 20 and 100, or between 30 and 100, or between 40 and 100, or between 50 and 100, or between 60 and 100, or between 70 and 100. , or between 80 and 100, or between 90 and 100, or between 61 and 100, or between 62 and 100, or between 63 and 100, or between 64 and 100, or between 65 and 100, or between 66 and 100, or between 67 and 100, or between 68 and 100, or between 69 and 100.

[0068] In some embodiments, the average aspect ratio is between 67 and 100.

[0069] In some embodiments, the cellulose nanomaterial is CNC. In some embodiments, the nanomaterial is not NFC.

[0070] Depending on the process used to produce the CNC, the material can be in a variety of purities. In some cases, the cellulose nanomaterial may comprise salts and/or carbohydrates, such as hemicellulose, xyloglucan, cellulose derivatives and others. Thus, the CNC used according to the invention may comprise between 0.01% and 0.5% of impurities, for example carbohydrates and salts.

[0071] Layer B endows the multilayer structure with one or more properties that can be enhanced, reduced or otherwise modified by selecting an appropriate substrate or covering layer or by increasing or decreasing or selecting a certain number of layers. In some embodiments, the material composition of layer B is selected to exhibit gas barrier properties, oil barrier properties, and water vapor barrier properties. Gas barrier properties include preventing, trapping or minimizing the permeation or transport of gases through the multilayer structure, the gas being selected from oxygen, carbon dioxide, aroma, SOx, NOx, methane, fluorinated gases and others . Oil barrier properties include preventing, trapping or minimizing the permeation or transport of oils such as vegetable oil, mineral oil and grease.

[0072] Layer B can also be selected to have a composition or thickness that provides the multilayer structure with mechanical support. It can be a transparent or opaque or non-transparent layer, and in some cases it can be adapted to block certain wavelengths.

[0073] In some embodiments, layer B comprises a mixture of CNC with at least one other nanocellulose material, such as NFC, or with at least one additive, or with at least one additional material.

[0074] In some embodiments, layer B consists of CNC or a combination of CNC and NFC.

[0075] A mixture of CNC and NFC is a mixture of the two components in a ratio between 0.001:1 and 1:0.001 (CNC to NFC). In some embodiments, the ratio is 0.001:1, 0.01:1, 0.1:1, 1:1, 1:0.1, 1:0.01, 1:0.001 w/w, CNC:NFC.

[0076] In some embodiments, layer B comprises CNC in combination with (as a blend) at least one polymer selected from polyvinyl alcohol (PVOH), polyvinyl acetate (PVAc), ethylene vinyl alcohol (EVOH), polyvinylpyrrolidone ( PVP), starch, chitosan, polyacrylic acid (PAA), polyethyleneimine (PEI), carbohydrates, ethylene vinyl acetate (EVA), elastomers, isocyanates and polyurethanes.

[0077] In some embodiments, layer B is a CNC layer that may consist of CNC or may comprise a blend (a mixture, not separate layers) of CNC and at least one additive selected to provide the CNC material or layer with one or more More properties selected from gas barrier, oil barrier, water vapor barrier, better mechanical properties, thermal properties, adhesive properties and others.

[0078] In some embodiments, B is a layer of a mixture of CNC and PVOH.

[0079] The at least one additive may be a polymer, as defined herein, or any other additive, such as a plasticizer, for example, glycerol or sorbitol; a surfactant, for example polysorbate; a particulate material, for example Mg particles or nanoparticles (excluding nanoparticles of other elements); a pigment; a carbohydrate, for example starch or chitosan; a salt, for example calcium carbonate; a conductive material, for example graphene; an oxygen scavenger, for example iron salts; lignin; natural extracts, for example, rosemary oil and others.

[0080] In some embodiments, the additive or any other material used in combination with the CNC and/or NFC is not bioriented polypropylene (BOPP).

[0081] In some embodiments, the additive is a polymeric material.

[0082] In some embodiments, the additive is not a polymeric material.

[0083] Where the additive is not a polymer, the additive may be present in amounts as indicated herein or in amounts ranging from 1% and 30% of the total weight of the formula (w/w). In some embodiments, the amount of additive may be between 1 and 10%, 1 and 20%, 1 and 5%, 5 and 10%, 10 and 15%, or 10 and 20%.

[0084] The cellulose nanomaterial layer, e.g., CNC, may be composed of nanomaterial, such as CNC, and at least one additional agent or material, e.g., a polymeric material, wherein the amount of the additive, e.g., material polymeric, varies between 0.1 and 99% by weight of the nanomaterial layer (in relation to the total weight of the materials that make up the layer). In some embodiments, the amount of polymeric material is between 0.1 and 95%, 0.1 and 90%, 0.1 and 85%, 0.1 and 80%, 0.1 and 75%, 0.1 and 70%, 0.1 and 65%, 0.1 and 60%, 0.1 and 55%, 0.1 and 50%, 0.1 and 45%, 0.1 and 40%, 0.1 and 35 %, 0.1 and 30%, 0.1 and 25%, 0.1 and 20%, 0.1 and 15%, 0.1 and 10%, 0.1 and 9%, 0.1 and 8% , 0.1 and 7%, 0.1 and 6%, 0.1 and 5%, 0.1 and 4%, 0.1 and 3%, 0.1 and 2%, 0.1 and 1%, 1 and 90%, 5 and 90%, 10 and 90%, 15 and 90%, 20 and 90%, 25 and 90%, 30 and 90%, 35 and 90%, 40 and 90%, 45 and 90%, 50 and 90%, 55 and 90%, 60 and 90%, 65 and 90%, 70 and 90%, 75 and 90%, 80 and 90%, 85 and 90%, 1 and 85%, 5 and 80%, 10 and 80%, 15 and 75%, 20 and 70%, 25 and 65%, 30 and 60%, 35 and 55% or 40 and 50%.

[0085] In some embodiments, the at least one additional material is a polymer, such as PVOH, present in an amount between 50 and 70% or between 60 and 70% or between 70 and 95% or between 70 and 80% of a composition which consists of the additive and CNC (in other words, an amount between 70% and 90% polymer means 70 to 90% polymer and 30 to 10% CNC).

[0086] In some embodiments, the ratio of at least one additional material to CNC is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1 or 2:1.

[0087] In some embodiments, layer B comprises CNC and PVOH (CNC-PVOH). The layer has a thickness of between 100 nm and 20 μm. In some embodiments, the thickness is between 100 and 900 nm, between 900 nm and 20 μm, between 1,000 nm and 20 μm, between 1 μm and 20 μm, or between 1 μm and 10 μm.

[0088] In some embodiments, the thickness is between 1 μm and 20 μm, between 1 μm and 20 μm, between 1 μm and 15 μm, between 1 μm and 10 μm or between 1 μm and 5 μm.

[0089] Each of layers A and C provides the multilayer structure with mechanical and barrier capabilities that can be adapted to meet one or more end applications. Both the substrate and the cover layer may be printed, laminated or otherwise associated with one or more layers, sheets, films or coatings. A multilayer structure having the general shape ABC, may be folded or arranged in a pocket or a container or a wrapper such that A or C may be the outer surface of the pocket or container or wrapper, or the inner surface thereof. Depending on the final product, the material or composition of each of the A and C layers can be selected.

[0090] In some embodiments, each of layers A and C is selected, independently of the others, from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate.

[0091] In some embodiments, one of layers A and C is a polymer-coated cardboard, wherein the polymer is selected from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate.

[0092] In some embodiments, at least one of layers A and C, independently of the other, is or comprises a tissue. The fabric can be any textile, natural fabric, synthetic fabric, mesh, woven material, non-woven material or mesh from a material selected from cellulose, viscose, glass fibers, carbon fibers and synthetic fibers. Likewise, the fabric may be in the form of a membrane, selected as indicated.

[0093] Layers A and B and/or layers B and C can be associated with each other directly or can be separated by an interface material (or interface materials), as represented for exemplification purposes in Figure 2. The interface material between A and B need not be the same as the interface material joining layers B and C, or one or both interface materials may be missing. Regardless of whether or not the layers are directly associated or associated via an interface material, the substrate layer and/or the cover layer can be pretreated to allow for a stable and long-lasting association between the layers. Pretreatment may involve one or more of plasma, corona, flame, heat or any known pretreatment methods.

[0094] Additionally or alternatively, the layers may be adhesively associated with each other, as defined, by means of a primary material or an adhesive material, shown in Figure 2 as the layers between layers A and B or between layers B and C. Such primer or adhesive may be inherent to the substrate or cover layer (namely embedded within the substrate/cover layer or pre-associated with the substrate/cover layer or is the substrate/cover layer material) and, therefore, it cannot be added as a separate film or layer or as a separate pretreatment or process step. In cases where primary or adhesive materials are not part of the substrate or cover layer, they may be coated on the substrate or cover layer to form an additional layer whose purpose may be to induce adhesion or association between the layers and which, typically, although optionally, it does not have an effect on any mechanical or functional or otherwise characteristic properties of the multilayer structure. The primary or adhesive layer or film is not normally used to endow the multilayer structure with one or more functional properties. However, the selection of a primary or adhesive material may be to further introduce, strengthen or diminish one or more properties associated with the multilayer structure as a whole or one or more layers thereof. This property can be foldability, elasticity, transparency, absorptivity, light transmittance, permeability of gases or solvents, wettability, thermal resistance and others. The primary layer or adhesive layer comprises a material selected from polyurethane, epoxy, acrylate, hot-melt adhesives, polyelectrolytes (e.g., polyethyleneimine) and varnish materials.

[0095] As can be understood, the adhesive or primer can also be used to associate any two or more layers of the multilayers with each other. The layers thus associated do not need to be the substrate or the covering layer. They can be any layer of the multilayers with any other layer of the multilayers.

[0096] In some embodiments, the multilayer structure comprises 3 layers: a substrate layer (A), a CNC layer (B) and a cover layer (C), each as defined herein, as exemplified in Figure 1 In some embodiments, the multilayer structure comprises 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 layers, such that at least one layer constitutes a substrate layer, as defined, a cellulose nanomaterial layer, as defined. defined, and a coverage layer as defined. In some embodiments, the material of each layer may be different from the material of an adjacent layer or the material of one or more other layers in the multilayer structure, or may be different from a material of any adjacent layer but the same as the material of a non-adjacent layer. For example, in a multilayer structure of the form ABCC, the layer of material A may be different from each of the layers of material C and each of the layers of material C may also be different from each other, forming a multilayer structure of the form ABC1C2 . Exemplary multilayer structures are provided in Figures 3A-D.

[0097] In such multilayer designations, both Cl and C2 are selected as defined herein for C, but are, however, different from each other.

[0098] In some embodiments, each of layers A and C is repeated twice or more, namely, a multilayer structure may be in the form AABCC, or ABCC, or AABC, or AABCBC, or ABCBCC, in which each of A, B and C are as defined herein, and further wherein each pair of adjacent layers may be associated directly or by means of a primary or adhesive film or layer. For example, in an AABCC structure, each A can be different from another and each C can be different from another C. Because material layers A and C can be selected from the same materials, the multilayer structure can be symmetric around the central B or asymmetric layer.

[0099] The multilayer structure of the invention may be in the form of a sheet or a folded or molded sheet of material, as defined herein. When presented as a sheet of material, it can be any size and shape, it can be printed or colored, it can be completely transparent or opaque, and it can be surface treated. The sheet may be cut, folded or processed into any shape, size or object, such as a pocket or a wrapper or an envelope or a container which is formed from the sheet, or which comprises at least one element or feature which is made of a structure multilayer of the invention. In some embodiments, the subject matter is the packaging of goods, food, liquids, pharmaceuticals, or any material that requires insulation or protection from the environment, e.g., gases, water vapor, certain wavelengths of light, and other agents or effects. damage that the multilayer structure can protect (forming an impermeable barrier).

[00100] Due to its unique properties, the foil can be used as a substitute for aluminum foil in packaging materials. As is known in the field, aluminum foils are widely used in packaging products due to their ability to completely block the permeation of gases, water and light, and also due to their contribution to the mechanical stability of the packaging. There are, however, certain disadvantages to using aluminum foil, mainly related to its impact on the environment caused by its inability to degrade and difficulties associated with recycling packaging containing aluminum. Aluminum's light-blocking properties are also considered a disadvantage when transparent packaging is required. Another disadvantage of aluminum is heat transmission, which is not desired in applications such as vacuum insulated panels where a good gas barrier is required but without high heat transfer.

[00101] The layered structure of the invention is a suitable replacement for aluminum by providing a material with barrier and mechanical properties, with the benefit of being recyclable and degradable, being transparent to light, thermal insulating and can be provided with barrier layers much thinner, achieving the same desired barrier properties (e.g. a 2 μm barrier layer leads to the desired OTR level in a structure where 5 μm aluminum foil is generally used).

[00102] Thus, according to some aspects, the invention provides an article in the form of a multilayer structure consisting of between 3 and 7 layers of material, the multilayer structure being of the form ABC, wherein each of A, B and C is a material layer selected as indicated in this document. In some modalities:

[00103] Layer A is a substrate comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose/polymer film , a fabric material, a porous material, a membrane material, a mineral material and a varnish;

[00104] Layer B is CNC-PVOH or a cellulose nanomaterial selected from nanocrystals (CNC), microfibrillated cellulose (MFC), a combination of CNC and NFC, a combination of CNC and MFC, and a mixture of CNC with at least one agent or water-soluble or water-dispersible material, or additive, as the case may be;

[00105] Layer C is a cover layer comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose film /polymer, a fabric material, a porous material, a membrane material, a mineral material and a varnish material.

[00106] In some embodiments, the cellulose nanomaterial layer comprises between 0.1% by weight and 3% by weight of impurities of the total weight of the layer, wherein the impurities are selected from carbohydrates and salts.

[00107] In some embodiments, the article consists of a CNC layer or a CNC blend layer and at least one additional agent; a substrate and a cover layer.

[00108] In some embodiments, the article consists of a layer of a mixture of CNC and PVOH; a substrate and a cover layer.

[00109] In some embodiments, each of layer A and layer C is a paper or paper-based material.

[00110] In some embodiments, each of layer A and layer C is a polymeric material, a polymer-coated paper-based material, or a nanocellulose/polymer film.

[00111] In some embodiments, layer B comprises CNC mixed with at least one polymer selected from PVOH, PVAc, EVOH, PVP, starch, chitosan, polyacrylic acid, polyethyleneimine, carbohydrates, EVA, elastomers, isocyanates and polyurethanes.

[00112] In some embodiments, the at least one additive is a polymer or an additive selected from a plasticizer; a surfactant; a particulate material; a pigment; a carbohydrate; a salt; a conductive material; and an oxygen scavenger.

[00113] In some embodiments, the at least one additive is present in an amount ranging from 1% to 20%.

[00114] In some embodiments, layer B is 100 nm to 20 μm thick.

[00115] In some embodiments, each of layer A and layer C is of a material selected, independently of the others, from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate.

[00116] In some embodiments, one or both of layers A and C is a polymer-coated cardboard, wherein the polymer is selected from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, acid polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, chloride polyvinyl and polycarbonate.

[00117] In some embodiments, at least one of layers A and C, independently of the other, is or comprises a tissue.

[00118] In some embodiments, layers A and B and/or layers B and C are associated with each other directly or separated by an interface material selected from a primary material and an adhesive material.

[00119] In some embodiments, the article consists of 3 layers: a substrate layer, a CNC layer, and a cover layer.

[00120] In some embodiments, the CNC layer consisting of a mixture of CNC and PVOH.

[00121] In some embodiments, the multilayer structure is in a form selected from AABCC, ABCC, AABC, AABCBC, ABCBCC, wherein each of A, B and C are as defined herein.

[00122] In some embodiments, the article is provided when used in packaging goods, foods, liquids and pharmaceuticals.

[00123] The invention further provides an article in the form of a multilayer structure consisting of between 3 and 7 layers of material, the multilayer structure being of the form ABC, wherein each A, B and C is a layer of material, in what:

[00124] Layer A is a substrate comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose/polymer film , a fabric material, a porous material, a membrane material, a mineral material and a varnish material;

[00125] Layer B is a cellulose nanomaterial selected from nanocrystals (CNC) and a mixture of CNC with at least one water-soluble or water-dispersible additive or material, wherein the layer is free of metallic nanoparticulate material and cellulose nanofibrillated (NFC);

[00126] Layer C is a cover layer comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose film /polymer, a fabric material, a porous material, a membrane material, a mineral material and a varnish material.

[00127] Packaging with good gas barrier properties is suitable for long-term aseptic packaging of food and beverages. Therefore, it is very important to achieve very low oxygen transmission rates (OTR) in developed packaging solutions. Furthermore, these low OTR values must be achieved in humid conditions, which better correlate with "real life" conditions and better predict the barrier's performance in imparting longer shelf life to packaged foods or beverages. An excellent oxygen barrier will show OTR values below 10 cm3/m2-day. A good oxygen barrier will show OTR values of a few tens and so on. OTR values, measured using a coulometric oxygen sensor, are crucial in determining final barrier product performance, and an improvement of just a few OTR units can attest to a big difference in the final packaging's ability to extend product shelf life. For this reason, the better OTR values achieved for structures consisting of a CNC-PVOH barrier layer compared to structures consisting of a PVOH barrier layer indicate that the final package will be superior when using CNC-PVOH as a barrier layer.

[00128] Thus, the invention also provides multilayer structures, as defined, in which layer B comprises or consists of a mixture of CNC and PVOH in proportions as indicated in the present document. The ratio of CNC to PVOH in the mixture can be selected from 1:1 and 1:40 CNC/PVOH, as detailed in this document.

[00129] The following non-limiting examples of the invention represent multilayer structures that by themselves or when modified to include one or more additional layers of material, provide a beneficial improvement on existing structures known in the art. In some embodiments, the multilayer structures of the invention consist of or comprise any one or more of the following (in each of the examples, the "/" sign indicates separation between layers):

[00130] -a paper or paper-based material (such as Kraft paper)/CNC-PVOH blend;

[00131] - a paper or paper-based material (such as Kraft paper)/CNC-PVOH blend/polymeric water vapor barrier (such as styrene, styrene-butadiene acrylic polymers and varnishes);

[00132] - a polyolefin (such as polypropylene)/a paper or paper-based material (such as Kraft paper)/CNC-PVOH blend/polymeric water vapor barrier (such as styrene, styrenebutadiene acrylic polymers and varnishes)/polyolefin ( such as polypropylene);

[00133] - a polyolefin (such as polypropylene)/a paper or paper-based material (such as Kraft paper)/CNC-PVOH blend/a polyolefin (such as polypropylene) - in such embodiments, each of the polyolefins may be the same or different;

[00134] -Cardboard (PB)/CNC-PVOH mix;

[00135] -Cardboard/CNC-PVOH blend/polymeric water vapor barrier (such as styrene, styrene-butadiene acrylic polymers and varnishes);

[00136] - a polyolefin (such as polypropylene)/Cardboard/CNC-PVOH blend/a polyolefin (such as polypropylene);

[00137] - a polyolefin (such as polypropylene)/cardboard/a polyolefin (such as polyethylene)/CNC-PVOH blend/a polyolefin (such as polypropylene) - in such embodiments, each of the polyolefins can be the same or different;

[00138] - a polyolefin (such as polypropylene)/CNC-PVOH blend;

[00139] - polyolefin (such as polypropylene)/mescal CNC-PVOH/polymeric water vapor barrier (such as styrene, styrene-butadiene acrylic polymers and varnishes);

[00140] - a polyolefin (such as polypropylene)/CNC-PVOH blend/a polyolefin (such as polypropylene) - in such embodiments, each of the polyolefins can be the same or different;

[00141] - biodegradable plastic (such as polyhydroxyalkenoate, PHA)/CNC-PVOH blend;

[00142] - biodegradable plastic (such as PHA)/mezcal CNC-PVOH/polymeric water vapor barrier (such as styrene, styrene-butadiene acrylic polymers and varnishes); It is

[00143] - biodegradable plastic (such as PHA)/CNC-PVOH formula/biodegradable plastic (such as PH A).

[00144] The following are specific properties:

[00145] 1. A structure: Kraft paper/CNC-PVOH blend

[00146] Kraft is a paper with a weight that varies from 30 to 50 g/m2, with the CNC-PVOH blend barrier layer having a weight that varies from 1 to 15 g/m2 or 3 to 6 g/m2. m2.

[00147] These multilayers are characterized by:

[00148] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23b °C;

[00149] b. Structure grease barrier according to TAPPI T 559 which is: 12 or higher.

[00150] 2. A multilayer structure: Kraft paper/CNC-PVOH blend/polymeric water vapor barrier (styrene-butadiene)

[00151] Kraft which has a weight between 30 and 50 g/m2, with the CNC-PVOH blend layer having a weight between 1 and 15 g/m2 or between 3 and 6 g/m2 and the polymeric vapor barrier of water has a weight of between 3 and 20 g/m2 or between 3 and 10 g/m2.

[00152] These multilayers are characterized by:

[00153] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00154] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher;

[00155] c. Water vapor transmission rate < 50 g/m2-day @ 90% RH, 38 °C;

[00156] d. Water sorption, according to the COBB -60 test, is at least 40 times better than Kraft paper - 30 to 40 g/m2 for Kraft paper compared to 0.1 to 0.7 g/m2 for multilayer structure.

[00157] 3. A multilayer structure: a polyolefin (such as polypropylene)/Kraft paper/CNC-PVOH blend/polymeric water vapor barrier/polyolefin (such as polypropylene).

[00158] Kraft which has a weight between 30 and 50 g/m2, with the CNC-PVOH blend layer having a weight between 1 and 15 g/m2 or between 3 and 6 g/m2 and the polymeric vapor barrier of water has a weight of between 3 and 20 g/m2 or between 3 and 10 g/m2 and each of the polyolefin layers has a thickness between 15 and 30 μm.

[00159] These multilayers are characterized by:

[00160] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00161] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher; The grease barrier remains effective after creasing and folding the structure.

[00162] c. Water vapor transmission rate of < 5 g/m2-day @ 90% RH, 38 °C;

[00163] d. No water sorption to the structure.

[00164] 4. A multilayer structure: a polyolefin (such as polypropylene)/Kraft paper/CNC-PVOH blend/a polyolefin (such as polypropylene).

[00165] Kraft that has a weight between 30 and 50 g/m2, with the CNC-PVOH mixture layer having a weight between 1 and 15 g/m2 or between 3 and 6 g/m2, and each of the layers polyolefin are of a thickness between 15 and 30 μm.

[00166] These multilayers are characterized by:

[00167] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00168] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher; The grease barrier remains effective after creasing and folding the structure.

[00169] c. Water vapor transmission rate of < 5 g/m2-day @ 90% RH, 38 °C;

[00170] d. No water sorption to the structure.

[00171] In comparison to each of the exemplary multilayers above, a non-barrier Kraft paper exhibited no oxygen barrier, the paper failed the grease test, and demonstrated no water or water vapor barrier properties.

[00172] In some embodiments, layer A is a cardboard and layer B comprises a mixture of CNC and PVOH in a ratio as defined, for example, which is between 1:2 and 1:40 CNC/PVOH. Non-limiting examples include:

[00173] 5. A multilayer structure: Cardboard (PB)/CNC-PVOH blend.

[00174] PB has a weight between 200 and 500 g/m2, with the barrier layer having a weight between 1 and 15 g/m2.

[00175] These multilayers are characterized by:

[00176] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00177] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher.

[00178] 6. A multilayer structure: Cardboard/CNC-PVOH blend/polymeric water vapor barrier (such as styrene-butadiene).

[00179] PB has a weight between 200 and 500 g/m2, with the barrier layer having a weight between 1 and 15 g/m2 and the polymeric water vapor barrier having a weight between 3 and 20 g/m2 .

[00180] These multilayers are characterized by:

[00181] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C.

[00182] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher; The grease barrier remains effective after creasing and folding the structure.

[00183] c. Water vapor transmission rate of < 50 g/m2-day @ 90% RH, 38 °C.

[00184] d. Water sorption, according to the COBB -1,800 test, is at least 10 times better than cardboard - 70 to 90 g/m2 for cardboard compared to 4 to 7 g/m2 for the multilayer structure.

[00185] 7. A multilayer structure: a polyolefin (such as polypropylene)/Cardboard/CNC-PVOH blend/a polyolefin (such as polypropylene).

[00186] PB has a weight between 200 and 500 g/m2, with the barrier layer having a weight between 1 and 15 g/m2, and each of the polyolefin layers having a thickness between 15 and 30 μm.

[00187] These multilayers are characterized by:

[00188] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 5 cm3/m2- day @ 80% RH, 23 °C;

[00189] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher;

[00190] c. Water vapor transmission rate of < 5 g/m2-day @ 90% RH, 38 °C;

[00191] d. No water sorption to the structure.

[00192] Comparative studies on each of the exemplary multilayers above indicated that cardboard without the CNC/PVOH barrier layer did not exhibit an oxygen barrier, the cardboard failed the grease test and did not demonstrate water or water vapor barrier properties.

[00193] 8. A multilayer structure: a polyolefin (such as polypropylene)/cardboard/a polyolefin (such as polyethylene)/CNC-PVOH blend/a polyolefin (such as polypropylene).

[00194] PB has a weight between 200 and 500 g/m2, with the barrier layer having a weight between 1 and 15 g/m2, polyethylene having a weight between 5 and 20 g/m2 and each of the layers polyolefin has a thickness between 15 and 30 μm.

[00195] These multilayers are characterized by:

[00196] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 5 cm3/m2- day @ 80% RH, 23 °C;

[00197] b. Grease barrier according to the TAPPI T 559 standard which is: 12 or higher;

[00198] c. Water vapor transmission rate of < 5 g/m2-day @ 90% RH, 38 °C;

[00199] d. No water sorption to the structure.

[00200] Non-barrier cardboard demonstrated no oxygen barrier, failed the grease test, and had no water or water vapor barrier properties. When coated with a polyolefin, cardboard does not yet demonstrate oxygen barrier properties.

[00201] 9. A multilayer structure: a polyolefin (such as polypropylene)/CNC-PVOH blend.

[00202] The CNC-PVOH mixture had a weight between 3 and 10 g/m2, the polyolefin layer had a thickness between 15 and 30 μm.

[00203] These multilayers are characterized by:

[00204] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C.

[00205] 10. A multilayer structure: a polyolefin (such as polypropylene)/CNC-PVOH blend/polymeric water vapor barrier (such as styrene-butadiene).

[00206] The CNC-PVOH blend had a weight between 3 and 10 g/m2, the polyolefin layer had a thickness between 15 and 30 μm and the polymeric water vapor barrier had a weight between 3 and 20 g/m2.

[00207] These multilayers are characterized by:

[00208] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C.

[00209] b. Water vapor transmission rate of < 5 g/m2-day @ 90% RH, 38 °C.

[00210] 11. A multilayer structure: a polyolefin (such as polypropylene)/CNC-PVOH blend/a polyolefin (such as polypropylene).

[00211] The CNC-PVOH mixture had a weight between 3 and 10 g/m2, the polyolefin layer had a thickness between 15 and 30 μm.

[00212] These multilayers are characterized by:

[00213] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00214] b. Water vapor transmission rate of < 5 g/m2-day @ 90% RH, 38 °C.

[00215] As comparative experiments demonstrated, a barrier-free polyolefin such as PP did not have oxygen barrier properties.

[00216] 12. A multilayer structure: biodegradable plastic (such as PHA)/CNC-PVOH blend.

[00217] The CNC-PVOH mixture had a weight between 3 and 10 g/m2, the PHA layer had a thickness between 25 and 200 μm.

[00218] These multilayers are characterized by:

[00219] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C.

[00220] 13. A multilayer structure: biodegradable plastic (such as PHA)/CNC-PVOH blend/polymeric water vapor barrier (such as styrene-butadiene).

[00221] The CNC-PVOH blend had a weight between 3 and 10 g/m2, the PHA layer had a thickness between 25 and 200 μm and the polymeric water vapor barrier had a weight ranging between 3 and 20 g/m2 m2.

[00222] These multilayers are characterized by:

[00223] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00224] b. Water vapor transmission rate of < 40 g/m2-day @ 90% RH, 38 °C.

[00225] 14. A multilayer structure: biodegradable plastic (such as PHA)/CNC-PVOH blend/biodegradable plastic (such as PHA).

[00226] The CNC-PVOH mixture had a weight between 3 and 10 g/m2, the PHA layer had a thickness between 25 and 200 μm.

[00227] These multilayers are characterized by:

[00228] a. Oxygen transmission rate of < 1 cm3/m2-day @ 50% RH, 23 °C; or < 15 cm3/m2-day @ 80% RH, 23 °C;

[00229] b. Water vapor transmission rate of < 200 g/m2-day @ 90% RH, 38 °C;

[00230] Comparative studies indicate that barrier-free PHA has an oxygen barrier rate of > 50 cm3/m2-day. The water vapor barrier of PHA is not as good as that of non-bioplastics. The water vapor transmission rate was reduced by 3 to 20 times when PHA was coated with a polymeric water vapor barrier as selected herein.

[00231] As indicated, the multilayer structures of the invention have exhibited improved oxygen transmission rates, water vapor transmission rates, grease and oil barrier capabilities, as well as water absorption properties, just to name a few, in comparison with the multilayers of the technique.

[00232] For example, improved properties of multilayer oil barrier comprising a CNC-PVOH blend layer over PVOH-based layers or water vapor polymer layers when coated on Kraft paper or paperboard have been demonstrated:

[00233] 1. Polymeric water vapor barriers, based on styrene-butadiene, acrylic emulsions, lacquer etc., coated on Kraft paper or cardboard with a coating weight of < 10 g/m2 resulted in TAPPI T 559 standard classification < 8, which is not sufficient for packaging purposes. They also do not show resistance to creases and folds.

[00234] 2. A PVOH layer with a coating weight of < 5 g/m2 resulted in a maximum TAPPI T 559 standard rating of 10 and showed no crease resistance.

[00235] 3. A layer of PVOH with a coating weight of < 5 g/m2, coated with a polymeric water vapor barrier with a coating weight of < 5 g/m2 (total coating of < 10 g/m2 ), resulted in a maximum standard TAPPI T 559 rating of 11 and showed no crease resistance.

[00236] 4. A CNC-PVOH layer with a coating weight of < 5 g/m2 resulted in a TAPPI T 559 standard rating of 12 (or more) and showed no crease resistance.

[00237] 5. A CNC-PVOH layer with a coating weight of < 5 g/m2, coated with a polymeric water vapor barrier with a coating weight of < 5 g/m2 (total coating of < 10 g/m2 m2), provided a standard TAPPI T 559 rating of 12 (or more) and was completely crease resistant.

[00238] Thus, a CNC-PVOH layer in a multilayer structure of the invention demonstrated improved properties that act as a barrier layer and additionally demonstrated a synergistic effect with polymeric water vapor barrier layers, especially those based on acrylic emulsions. or styrene-butadiene emulsions. The combination of the two layers has led to improved oil/grease barrier capabilities, which include resistance to creasing and folding, which are essential in the production of liquid and food packaging.

[00239] The invention thus provides:

[00240] An article in the form of a multilayer structure characterized by comprising three or more layers of material, at least one of said three or more layers of material being a substrate layer and at least one other of said three or more layers being of material being a layer of a mixture of cellulose nanocrystals (CNC) and polyvinyl alcohol (PVOH).

[00241] The following embodiments refer to any of the aspects disclosed in this document, as well as to any disclosed embodiments, in combination.

[00242] In some embodiments, the article is characterized by one or more of the following:

[00243] (1) a grease barrier of 12, as determined using TAPPI T 559 standard (approved by the Physical Properties Committee of the Process and Product Quality Division);

[00244] (2) an oxygen transmittance rate (OTR) of between 0.01 and 15 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C; and/or

[00245] (3) a water vapor transmittance rate (WVTR) of between 0.01 and 20 g/m2-day, when measured at 90% RH, at 38 °C.

[00246] In some embodiments, the ORT is between 0.01 and 1 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C.

[00247] In some embodiments, the ORT is between 0.01 and 5 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C.

[00248] In some embodiments, the ORT is between 1 and 10 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C.

[00249] In some embodiments, the ORT is between 1 and 5 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C.

[00250] In some embodiments, the ORT is below 1 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C.

[00251] In some embodiments, the WVTR is between 0.01 and 1 g/m2-day, when measured at 90% RH, at 38 °C.

[00252] In some embodiments, the WVTR is between 0.01 and 5 g/m2-day, when measured at 90% RH, at 38 °C.

[00253] In some embodiments, the WVTR is between 1 and 10 g/m2-day, when measured at 90% RH, at 38 °C.

[00254] In some embodiments, the WVTR is between 1 and 5 g/m2-day, when measured at 90% RH, at 38 °C.

[00255] In some embodiments, the WVTR is between 5 and 10 g/m2-day, when measured at 90% RH, at 38 °C.

[00256] In some embodiments, the WVTR is below 10 g/m2-day, when measured at 90% RH, at 38 °C.

[00257] In some embodiments, the article is biodegradable.

[00258] In some embodiments, the mixture of CNC and PVOH is a mixture of CNC and PVOH at a ratio between 0.001:1 to 1:0.001 (CNC to PVOH).

[00259] In some embodiments, the ratio is 0.001:1, 0.01:1, 0.1:1, 1:1, 1:0.1, 1:0.01, 1:0.001 w/w, CNCPVOH .

[00260] In some embodiments, the article consists of between 3 and 7 layers of material, with the multilayer structure being of the form ABC, in which each of A, B and C designates a single layer or two or more layers of a material :

[00261] Layer A is a substrate comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose/polymer film , a fabric material, a porous material, a membrane material, a mineral material and a varnish;

[00262] Layer B is a CNC-PVOH blend layer, which optionally comprises at least one additional material; It is

[00263] Layer C is a cover layer comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose film /polymer, a fabric material, a porous material, a membrane material, a mineral material and a varnish.

[00264] In some embodiments, the CNC-PVOH blend layer further comprises at least one additional material selected from polyvinyl acetate (PVAc), ethylene vinyl alcohol (EVOH), polyvinylpyrrolidone (PVP), starch, chitosan, polyacrylic acid (PAA), polyethyleneimine (PEI), carbohydrates, ethylene vinyl acetate (EVA), elastomers, isocyanates, polyurethanes and inert fillers.

[00265] In some embodiments, said CNC-PVOH blend layer consists of CNC and PVOH.

[00266] In some embodiments, in an ABC structure, layer B comprises a CNC-PVOH blend layer and a layer of a cellulose nanomaterial selected from nanocrystals (CNC), microfibrillated cellulose (MFC), a combination of CNC and NFC, a combination of CNC and MFC, a blend of CNC with at least one water-soluble or water-dispersible additive, and a blend of CNC with one or more additional materials selected from polyvinyl alcohol (PVOH), polyvinyl alcohol (PVOH), polyvinyl (PVAc), ethylene vinyl alcohol (EVOH), polyvinylpyrrolidone (PVP), starch, chitosan, polyacrylic acid (PAA), polyethyleneimine (PEI), carbohydrates, ethylene vinyl acetate (EVA), elastomers, isocyanates, polyurethanes and inert fillers .

[00267] In some embodiments, any one of the material layers comprises at least one additive selected from a polymer, a plasticizer, a surfactant, a particulate material (which includes nanoparticles and microparticles), a pigment, a carbohydrate, a salt , a conductive material, a scavenger of oxygen, lignin and natural extracts.

[00268] In some embodiments, the CNC-PVOH layer comprises between 0.1% by weight and 3% by weight of impurities of the total weight of the layer, wherein the impurities are selected from carbohydrates and salts.

[00269] In some embodiments, the article consists of a layer of a blend consisting of CNC and PVOH; a substrate layer and a cover layer.

[00270] In some embodiments, each of layer A and layer C is a paper or paper-based material.

[00271] In some embodiments, each of layer A and layer C is a polymeric material, a polymer-coated paper-based material, or a nanocellulose/polymer film.

[00272] In some embodiments, layer B is of a thickness of 100 nm to 20 μm.

[00273] In some embodiments, each of layer A and layer C is of a material selected independently of the others from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate.

[00274] In some embodiments, one or both of layers A and C is a polymer-coated cardboard, wherein the polymer is selected from polyethylene, polypropylene, polyester, polyvinyl alcohol, ethylene vinyl alcohol, polyamide, polystyrene, acid polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, polyacrylonitrile, polybutylene succinate, polyvinylidene chloride, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides, polyethylene terephthalate, polyvinyl chloride and polycarbonate.

[00275] In some embodiments, each of layers A and C is a biodegradable material selected independently of the other from polyvinyl alcohol, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, polyvinyl acetate, succinate of polybutylene, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides or any polymer mixture of two or more of the aforementioned polymers.

[00276] In some embodiments, one or both of layers A and C is a cardboard coated with a biodegradable polymer, wherein the biodegradable polymer is selected from polyvinyl alcohol, polylactic acid, polyhydroxyalkanoate, polycaprolactone, polyhydroxybutyrate, acetate of polyvinyl, polybutylene succinate, starch, cellulose, polyhydroxyvalerate, polyhydroxyhexanoate, polyanhydrides or any polymer mixture of two or more of the aforementioned polymers.

[00277] In some embodiments, at least one of layers A and C, independently of the other, is or comprises a tissue.

[00278] In some embodiments, layers A and B and/or layers B and C are associated with each other directly or separated by an interface material selected from a primary material and an adhesive material.

[00279] In some embodiments, the multilayer structure is in a form selected from AABCC, ABCC, AABC, AABCBC, ABCBCC, wherein each of A, B and C are according to claim 16.

[00280] In some embodiments, the article is used in packaging goods, foods, liquids and pharmaceutical products.

[00281] In some embodiments, the article comprises a substrate of paper or paper-based material and a CNC-PVOH blend layer.

[00282] In some embodiments, the article comprises 3 layers: a substrate of a paper or paper-based material, a CNC-PVOH blend layer, and a layer of a polymeric water vapor barrier material.

[00283] In some embodiments, the article comprises 5 layers: a layer of a polyolefin, a layer of a paper or paper-based material, a layer of CNC-PVOH blend, a layer of a water vapor barrier material polymer and an additional layer of a polyolefin.

[00284] In some embodiments, the article comprises 4 layers: a layer of a polyolefin, a layer of a paper or paper-based material, a CNC-PVOH blend layer and an additional layer of a polyolefin.

[00285] In some embodiments, the article comprises a cardboard and a CNC-PVOH blend layer.

[00286] In some embodiments, the article comprises 3 layers: a cardboard, a CNC-PVOH blend layer and a layer of a polymeric water vapor barrier material.

[00287] In some embodiments, the article comprises 4 layers: a layer of a polyolefin, a cardboard, a CNC-PVOH blend layer and an additional layer of a polyolefin.

[00288] In some embodiments, the article comprises 5 layers: a layer of a polyolefin, a cardboard, a second layer of a polyolefin, a CNC-PVOH blend layer and an additional layer of a polyolefin.

[00289] In some embodiments, the article comprises a layer of a polyolefin and a CNC-PVOH blend layer.

[00290] In some embodiments, the article comprises 3 layers: a layer of a polyolefin, a CNC-PVOH blend layer, and a layer of a polymeric water vapor barrier material.

[00291] In some embodiments, the article comprises 3 layers: a layer of a polyolefin, a CNC-PVOH blend layer and an additional layer of a polyolefin.

[00292] In some embodiments, the article comprises a layer of a biodegradable plastic material and a CNC-PVOH blend layer.

[00293] In some embodiments, the article comprises 3 layers: a layer of a biodegradable plastic material, a CNC-PVOH blend layer, and a layer of a polymeric water vapor barrier material.

[00294] In some embodiments, the article comprises 3 layers: a layer of a biodegradable plastic material, a CNC-PVOH blend layer, and an additional layer of a biodegradable plastic material.

[00295] In some embodiments, the article comprises 3 layers: a cardboard, a CNC-PVOH blend layer and a layer of a biodegradable plastic.

[00296] In some embodiments, the article comprises 4 layers: a layer of a biodegradable plastic, cardboard, a CNC-PVOH blend layer and an additional layer of a biodegradable plastic.

[00297] In some embodiments, the article comprises 5 layers: a layer of a biodegradable plastic, a cardboard, a second layer of a biodegradable plastic, a CNC-PVOH blend layer and an additional layer of a biodegradable plastic.

[00298] In some embodiments, the paper or paper-based material is Kraft paper or cardboard.

[00299] In some embodiments, the paper or paper-based material is Kraft paper.

[00300] In some embodiments, the polymeric water vapor barrier material is styrene, styrene-butadiene, an acrylic polymer, or a varnish.

[00301] In some embodiments, the polymeric water vapor barrier material is styrene or styrene-butadiene.

[00302] In some embodiments, the polyolefin is selected from polypropylene and polyethylene.

BRIEF DESCRIPTION OF THE DRAWINGS

[00303] In order to better understand the subject matter that is disclosed in this document and to exemplify how it can be carried out in practice, the embodiments will now be described, by way of non-limiting example, with reference to the attached drawings, in which :

[00304] Figure 1 represents an exemplary multilayer structure according to the invention.

[00305] Figure 2 represents another exemplary multilayer structure according to the invention.

[00306] Figures 3A to D represent different embodiments of another exemplary multilayer structure according to the invention.

DETAILED DESCRIPTION OF MODALITIES

[00307] In addition to the examples provided above, the following examples should be considered.

EXAMPLE 1: A 3-LAYER STRUCTURE:

[00308] Layer A: low-density polyethylene (LDPE) - 20 μm, treated with Crown

[00309] Layer B: a layer of PVOH/CNC - 5 g/m2

[00310] Layer C: low density polyethylene (LDPE) - 20 μm, crown treated and coated on the treated side with an adhesive

[00311] Multilayers include layer A/layer B/layer C

PREPARATION METHOD:

[00312] 1. The LDPE film (Layer A) was treated on the surface with crown;

[00313] 2. The PVOH/CNC aqueous suspension was coated on the treated LDPE surface, followed by complete drying (Layer B);

[00314] 3. Crown-treated LDPE film coated with an adhesive layer and laminated to Layer B, with the adhesive-coated side facing the PVOH/CNC layer (Layer C).

[00315] The multilayer structure was transparent, flexible and could be further laminated to include additional layers to produce flexible or rigid packaging with good barrier capabilities. The LDPE layers provided water, water vapor and oil barrier capabilities. The PVOH/CNC inner layer provided gas barrier capabilities.

EXAMPLE 2: A MULTI-LAYER STRUCTURE (3 LAYERS):

[00316] Layer A: polypropylene - 30 μm, coated with a layer of hot-melt adhesive (e.g., ethylene vinyl acetate)

[00317] Layer B: a layer of PVOH/CNC - 5 g/m2

[00318] Layer C: polypropylene - 30 μm, coated with a layer of hot-melt adhesive (e.g., ethylene vinyl acetate)

[00319] Multilayers include Layer A/Layer B/Layer C

PREPARATION METHOD:

[00320] 1. Polypropylene film (Layer A) is coated with a hot-melt adhesive (e.g., ethylene vinyl acetate)

[00321] 2. The PVOH/CNC aqueous suspension is coated on the hot melt layer, followed by complete drying (Layer B)

[00322] 3. Polypropylene film, coated with a hot-melt layer, is laminated to Layer B, with the adhesive-coated side facing the PVOH/CNC layer (Layer C)

[00323] The multilayer structure is transparent, flexible and could be subsequently laminated with additional layers to produce flexible or rigid packaging with good barrier capabilities. The polypropylene layers provide water, water vapor and oil barrier capabilities. The PVOH/CNC inner layer provides gas barrier capabilities and improves mechanical properties.

[00324] The mechanical properties of the layered structures described in Example 2 were tested by tensile tests, using an Instron machine:

[00325] • The elastic modulus is improved by 40% to 125% compared to the reference of layers A and C laminated together.

[00326] • Elongation at break is improved by 7 to 20% compared to the reference of layers A and C laminated together.

EXAMPLE 3: A 5-LAYER STRUCTURE:

[00327] Al layer: low density polyethylene (LDPE) - 20 μm

[00328] Layer A2: cardboard, coated with LDPE

[00329] Layer A3: low density polyethylene (LDPE) - 15 μm, crown treated

[00330] Layer B: a layer of PVOH/CNC - 4 g/m2

[00331] Cl layer: low density polyethylene (LDPE) - 15 μm, corona treated

[00332] Layer C2: low-density polyethylene (LDPE)

[00333] Multilayers include Al Layer/A2 Layer/B Layer/Cl Layer/C2 Layer

PREPARATION METHOD:

[00334] 1. The LDPE film (Layer A3) was treated on the surface with crown;

[00335] 2. The PVOH/CNC aqueous suspension was coated on the treated LDPE surface, followed by complete drying (Layer B);

[00336] 3. The corona-treated LDPE film was laminated to Layer B, with the corona-treated side facing the PVOH/CNC layer (Cl Layer);

[00337] 4. The LDPE was extruded onto the surface of a cardboard (layer A2);

[00338] 5. The LDPE was extruded from the other side of the cardboard (Al layer);

[00339] 6. The multilayer of layers A3/B/C1 was laminated onto layer A2;

[00340] 7. The LDPE was extruded into the Cl layer (C2 layer).

[00341] This multilayer structure can be used for rigid packaging. The cardboard layer provided mechanical stability, the LDPE layers provided water, water vapor and oil barrier capabilities. The PVOH/CNC inner layer provides gas barrier capabilities:

[00342] • This structure with layer B that has a barrier layer of ~1.2 g/m2 has OTR-4 at 80% RH.

[00343] • This structure with layer B that has a barrier layer of -2.4 g/m2 has OTR-2 at 80% RH.

[00344] • This structure with layer B that has a barrier layer of -4 g/m2 has OTR-1 at 80% RH.

[00345] • This structure with layer B that has a barrier layer of -5 g/m2 has OTR<1 at 80% RH.

Claims (15)

1. MULTILAYER STRUCTURE, characterized by consisting of between 3 and 7 layers of non-metallic material, with the multilayer structure being of the ABC form, in which each of A, B and C designates a single layer or two or more layers of a material : Layer A is a substrate comprising a material selected from a polymeric material, a paper or paper-based material, a polymer-coated paper-based material, a nanocellulose film, nanocellulose/polymer film, a fabric material, a porous material, a membrane material and a mineral material; Layer B is a CNC-PVOH blend layer, comprising at least one additional material, wherein layer B has a thickness between 1 μm and 20 μm; and Layer C is a top coat made of a varnish. 2. MULTILAYER STRUCTURE, according to claim 1, characterized in that the varnish layer is a varnish composition comprising a material selected from a polymer; a resin; latex; this is Leo. 3. MULTILAYER STRUCTURE, according to claim 2, characterized in that the polymer is a polyurethane, an acrylic, an epoxy or a polyester. 4. MULTILAYER STRUCTURE, according to claim 2, characterized in that the resin is a phenolic resin, an alkyl resin or a polyurethane resin. 5. MULTILAYER STRUCTURE, according to claim 1, characterized in that the latex is styrene, styrene-butadiene or natural latex. 6. MULTILAYER STRUCTURE, according to claim 1, characterized in that the oil is linseed oil, walnut oil, tung oil or soybean oil. 7. MULTILAYER STRUCTURE, according to claim 1, characterized by one or more of the following: (1) a grease barrier of 12, as determined using standard TAPPI T 559; (2) an oxygen transmittance rate (OTR) of between 0.01 and 15 cm3/m2-day, when measured at 80% relative humidity (RH), at 23 °C; and/or (3) a water vapor transmittance rate (WVTR) of between 0.01 and 20 g/m2-day, when measured at 90% RH, at 38 °C. 8. MULTILAYER STRUCTURE, according to claim 7, characterized in that the OTR is between 0.01 and 1 cm3/m2-day, when measured at 80% relative humidity (RH), at 23°C; or where the OTR is between 0.01 and 5 cm3/m2-day, when measured at 80% relative humidity (RH), at 23°C; or where the OTR is between 1 and 10 cm3/m2-day, when measured at 80% relative humidity (RH), at 23°C; or where the OTR is between 1 and 5 cm3/m2-day, when measured at 80% relative humidity (RH), at 23°C; or because an OTR is below 1 cm3/m2-day, when measured at 80% relative humidity (RH), at 23°C. 9. MULTILAYER STRUCTURE, according to claim 7, characterized in that the WVTR is between 0.01 and 1 g/m2-day, when measured at 90% RH, at 38°C; or where the WVTR is between 0.01 and 5 g/m2-day, when measured at 90% RH, at 38°C; or where the WVTR is between 1 and 10 g/m2-day, when measured at 90% RH, at 38°C; or where the WVTR is between 1 and 5 g/m2-day, when measured at 90% RH, at 38°C; or where the WVTR is between 5 and 10 g/m2-day, when measured at 90% RH, at 38°C; or where a WVTR is less than 1 g/m2-day when measured at 90% RH at 38°C. 10. MULTILAYER STRUCTURE, according to claim 1, characterized by being biodegradable. 11. MULTILAYER STRUCTURE, according to any one of claims 1 to 10, characterized in that the mixture of CNC and PVOH is a mixture of CNC and PVOH in a ratio between 0.001:1 to 1:0.001 (CNC to PVOH). 12. MULTILAYER STRUCTURE according to claim 1, characterized in that the CNC-PVOH blend layer further comprises at least one additional material selected from polyvinyl acetate (PVAc), ethylene vinyl alcohol (EVOH), polyvinylpyrrolidone (PVP), starch, chitosan, polyacrylic acid (PAA), polyethyleneimine (PEI), carbohydrates, ethylene vinyl acetate (EVA), elastomers, isocyanates, polyurethanes and inert fillers. 13. MULTILAYER STRUCTURE, according to claim 1, characterized in that said CNC-PVOH blend layer consists of CNC and PVOH. 14. MULTILAYER STRUCTURE, according to claim 1, characterized in that it is selected from: an article comprising 3 layers: a substrate of a paper or paper-based material, a CNC-PVOH blend layer and a layer of a polymeric water vapor barrier material; an article comprising 5 layers: a layer of a polyolefin, a layer of a paper or paper-based material, a CNC-PVOH blend layer, a layer of a polymeric water vapor barrier material and an additional layer of a polyolefin; an article comprising 3 layers: a cardboard, a CNC-PVOH blend layer and a layer of a polymeric water vapor barrier material; an article comprising 3 layers: a layer of a polyolefin, a CNC-PVOH blend layer and a layer of a polymeric water vapor barrier material; and an article comprising 3 layers: a layer of a biodegradable plastic material, a CNC-PVOH blend layer and a layer of a polymeric water vapor barrier material. 15. MULTILAYER STRUCTURE according to claim 1, characterized by the structure ABC1C2, wherein C1 is varnish and C2 is a material selected from a polymeric material, a paper or paper-based material, a paper-based material coated with polymer, a nanocellulose film, nanocellulose/polymer film, a fabric material, a porous material, a membrane material and a mineral material.