Packaging material with low moisture vapor transmission rate.

Abstract

The present invention relates to a food packaging material and a method of manufacturing a food packaging material. The food packaging material of the present invention comprises a paper substrate having a first side and a second side, the second side being opposite to the first side, wherein the paper substrate is coated on at least the first or the second side with a coating comprising wax and a copolymer selected from styrene butadiene copolymer and / or styrene acrylic copolymer.

Description

[001] The present invention relates to a food packaging material and a method of manufacturing a food packaging material. BACKGROUND OF THE TECHNIQUE

[002] Conventional food containers, such as pet food containers, are often made with plastic films and / or papers containing fluorinated compounds. Thanks to this structure, conventional pet food containers have a good grease barrier, a low moisture vapor transmission rate (MVTR), and mechanical properties suitable for storing, for example, pet food.

[003] However, there are concerns about food safety and the environment regarding fluorinated compounds, which are being banned in most countries. The plastic content in packaging is also linked to growing environmental concerns, as it is not fully recyclable.

[004] Although a general requirement of packaging is to protect the contents from external influences, such as moisture, for example, to prevent food from spoiling, goods also impose requirements on packaging. Packaging material intended for use in pet food containers must meet specific requirements. Pet food typically includes large amounts of oil and fat, therefore the packaging material for pet food needs to be grease-resistant. If the packaging material does not have satisfactory grease-resistant properties, grease will penetrate the material and cause grease stains. Petition 870260039395, dated 04 / 28 / 2026, page 7 / 68 2 / 49 will appear on the outer surface of the container. Furthermore, through grease leakage, the packaging material may lose its structural integrity, and the risk of the container breaking will increase.

[005] Furthermore, the packaging material used in pet food containers must have adequate mechanical properties for conversion, i.e., for the production of pet food containers. In addition, it is important that the packaging material be able to withstand the handling and weight of heavy loads, even when stored or transported in a humid environment. A standard weight of pet food units can reach 12 kg or even more. Therefore, a pet food packaging material must be able to withstand a high load. It is therefore necessary to obtain ideal properties of tensile strength, stiffness and tear resistance, along with ideal properties of grease resistance.

[006] The packaging material must also be made from materials that are safe for contact with food and, ideally, recyclable.

[007] Fluorine-free, paper-based packaging materials for the pet food market are often unsatisfactory from the point of view mentioned above because their grease barrier level, in the absence of fluorinated compounds, is too low both on the surface and inside the packaging material. Generally, these fluorine-free packaging materials use a laminated film, which often contains plastic, to increase the surface grease barrier. However, the use of laminated film reduces the recycling yield of the packaging, the biopolymer content, and does not improve the grease resistance of the material's core. Furthermore, lamination needs to be done off-machine, and production costs are higher than those of a method that can be... Petition 870260039395, dated 04 / 28 / 2026, page 8 / 68 3 / 49 completed entirely on the paper machine.

[008] Furthermore, packaging materials that do not include plastic films and / or papers containing fluorinated compounds are generally insufficient to control the moisture content of packaged products, such as food. However, in food packaging, moisture control can be crucial to maintaining food quality, ensuring its safety, and extending its shelf life. Thus, in addition to addressing the problems mentioned above, there is a need for a packaging material that extends the shelf life of moisture-sensitive food products. TECHNICAL PROBLEM

[009] There is a demand for a suitable food packaging material that is capable of controlling the moisture of moisture-sensitive products. An indicator of water vapor permeability through a substance is the moisture vapor transmission rate (MVTR). A low MVTR indicates an improved vapor barrier. More specifically, there is a demand for a food packaging material that has a low water vapor transmission rate (MVTR), such as an MVTR of less than 75 g / m² / 24h determined at 85% relative humidity (RH) and 23 °C.

[0010] Ideally, the packaging material should be substantially free of fluorinated compounds, such as per- and polyfluoroalkyl substances (PFAS), have good grease resistance properties, and maintain optimal mechanical strength to support high weight.

[0011] Furthermore, there is a demand for this packaging material to be manufactured with food-safe and recyclable materials. That is, conventional packaging materials, composed of plastic films, a large amount of coating and / or fluorinated chemicals, may have a low MVTR, Petition 870260039395, dated 04 / 28 / 2026, page 9 / 68 4 / 49 but recyclability would be affected. Therefore, there is a demand for a packaging material that offers satisfactory moisture barrier properties and is recyclable. SUMMARY OF THE INVENTION

[0012] The present invention aims to solve the aforementioned problems of the prior art by providing a food packaging material comprising a paper substrate with a first side and a second side, the second side being opposite to the first, wherein the paper substrate is coated at least on the first or second side with a coating comprising wax and a copolymer selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer.

[0013] Furthermore, the present invention relates to a method of manufacturing food packaging material, in which the coating is applied to the paper substrate, preferably by direct rotogravure, using a single bar, by curtain coating, by spray coating, by press-on coating, by air foil coating or by flexographic coating.

[0014] It has been found that coating a paper substrate with a layer composed of wax and a copolymer selected from at least one of the groups consisting of a styrene-butadiene copolymer and a styrene-acrylic copolymer makes it possible to obtain a food packaging material with low MVTR, thus extending the shelf life of moisture-sensitive food products.

[0015] Furthermore, the inventors of the present invention have found that the combination of wax and styrene copolymer, according to the invention, makes it possible to provide a packaging material with satisfactory moisture barrier properties, even when the coating is present only in relatively low quantities. This Petition 870260039395, dated 04 / 28 / 2026, page 10 / 68 5 / 49 allows for the supply of packaging material with satisfactory moisture barrier properties that is also recyclable.

[0016] Without intending to be bound by any theory, the combination of a wax with a styrene copolymer, according to the invention, appears to result in a particularly suitable interaction within the coating, which improves moisture barrier properties. The long aliphatic hydrocarbon chains present in the wax likely interact well with the hydrophobic parts of the copolymers. Furthermore, the hydrocarbon chains of the wax are more flexible in their configurations and can bend more easily than, for example, styrene copolymers, which have more bulky phenyl groups in their main structures. In this way, the hydrocarbon chains of the wax can fill the gaps in the porous structures of the paper substrate that were not blocked by the copolymer due to its rather rigid structure. As the hydrocarbon chains of the wax are water-repellent, the moisture barrier properties can be enhanced.

[0017] Furthermore, according to a preferred embodiment of the invention, enhanced grease barrier properties can be obtained by pre-coating the paper substrate with a grease barrier precursor prior to the coating of the invention. This can be useful for packaging food products, such as pet food, which are known to have a high fat content.

[0018] The food packaging material according to the present invention also allows for obtaining ideal mechanical properties. The objectives of the present invention are achieved without the introduction of plastic films and / or papers containing fluorinated compounds, thus resulting in a product that is safe for contact with food and has a lower environmental impact (i.e., greater recyclability). Petition 870260039395, dated 04 / 28 / 2026, page 11 / 68 6 / 49

[0019] The food packaging material of the present invention can therefore form packaging that extends the shelf life of moisture-sensitive food products, exhibiting ideal mechanical properties without the introduction of plastic films and / or papers containing fluorinated compounds.

[0020] Although the packaging material of the present invention is particularly suitable for products such as high-fat, high-weight pet food, it is also obviously suitable for other products, including not only food in general, but also non-food products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic illustration of an embodiment of the present invention.

[0022] Figure 2 is a schematic illustration of a preferred embodiment of the present invention, in which the coating layer additionally comprises a filler.

[0023] Figure 3 is a schematic illustration of a preferred embodiment of the present invention, in which the food packaging material further comprises an additional coating layer applied over the coating layer.

[0024] Figure 4 is a schematic illustration of a preferred embodiment of the present invention, in which the food packaging material additionally comprises a printing layer.

[0025] Figure 5 is a schematic illustration of a preferred embodiment of the present invention, in which the food packaging material further comprises an additional coating layer applied over the coating layer and a printing layer. DETAILED DESCRIPTION OF THE INVENTION Definitions Petition 870260039395, dated 04 / 28 / 2026, page 12 / 68 7 / 49

[0026] In the present invention, the term "average" denotes arithmetic mean, unless otherwise indicated.

[0027] In the present invention, references to quantities “by weight” should be understood as synonymous with “by mass”. Furthermore, as used in this document, the term percentage by weight (% by weight) refers to a percentage by weight.

[0028] In the present invention, the term "polymer" denotes a compound comprising at least ten repeating units, such as, for example, a homopolymer, a copolymer, a graft copolymer, a branched copolymer or a block copolymer.

[0029] In the context of the present invention, the term “biodegradable” is generally defined in accordance with EN 13432. The term “biodegradable”, when applied to a material or product, means that the material or product as a whole will biodegrade. By “biodegrade” it is understood that the chemical structure or material decomposes through the action of microorganisms. More specifically, a material or product is considered “biodegradable” if at least 90% by weight of the material is converted to CO2 by the action of microorganisms in less than 6 months, as measured by the laboratory test method EN 14046, thus meeting the biodegradability requirement according to EN 13432.

[0030] The term “compostable” is generally defined in accordance with EN 13432. In the context of the present invention, a material is “compostable” when it comprises a maximum of 10% by weight and, preferably, 5% by weight of non-biodegradable components, thus complying with EN 13432. The term “compostable”, when applied to a material or product, means that the material, or the entire product, will biodegrade and disintegrate. The term “disintegrates” means that the material, or the product made from it, physically breaks down into fine, visually indistinguishable fragments at the end of a Petition 870260039395, dated 04 / 28 / 2026, page 13 / 68 8 / 49 typical composting cycle.

[0031] A material that is “industrially compostable” may be compostable as described above in an industrial setting: The material may disintegrate and biodegrade at temperatures between 55°C and 60°C in less than 6 months. In detail, disintegration in an industrial setting may take less than 3 months, while biodegradation may take less than 6 months. If a material is described as “home compostable”, it will be compostable as described above under the conditions present in a home composting setting: The material may disintegrate and biodegrade at temperatures below 55°C, preferably at temperatures between 10°C and 45°C, and more preferably between 25°C and 30°C, in less than 12 months. In detail, disintegration may take less than 6 months, while biodegradation may take less than 12 months in a home composting setting.

[0032] When the present description refers to “preferred” features / characteristics, combinations of these preferred features / characteristics will also be considered described, provided that such combination is technically significant.

[0033] From now on, the use of the term “comprising” should be understood as a description in an unlimited way, i.e., additional components or steps may be present or implemented, provided that this is technically significant. For a more restricted implementation, the terms “consisting of” will be used and should be understood as a limited description, i.e., without any additional components or steps. Packaging material

[0034] The present invention relates to a food packaging material comprising a paper substrate with a first side and a second side, the second side being opposite to the first side, Petition 870260039395, dated 04 / 28 / 2026, page 14 / 68 9 / 49 wherein the paper substrate is coated on at least one or two sides with a coating comprising wax and a copolymer selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer.

[0035] With reference to Figure 1, the packaging material (1) of the present invention comprises a paper substrate (10) with a first side and a second side, the second side being opposite to the first side, which is optionally pre-coated at least on the first or second side with a grease barrier precursor (12), the paper substrate (10) being coated on a first side with a coating (11) comprising wax and a copolymer (13) selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer. Paper substrate

[0036] The term “paper substrate”, as used in this document, refers to a flat element, such as a sheet of paper, that has a first side and a second side, the second side being opposite the first.

[0037] The paper substrate of the present invention refers to a base paper before coating and the optional pre-coating described below.

[0038] In the present invention, the paper substrate is preferably a cellulose fiber base sheet.

[0039] The term “fiber,” as used in this document, refers to a form of material distinguished by an extremely high length-to-diameter ratio. In general, cellulose fibers exhibit a wide range of diameters and lengths, depending on the type and source of the fiber. The average length of a wood pulp fiber, as used in a preferred manner in the present invention, is typically between 0.3 mm and 3.5 mm, preferably. Petition 870260039395, dated 04 / 28 / 2026, p. 15 / 68 10 / 49 between 0.3 mm and 3.0 mm, more preferably between 0.8 mm and 2.5 mm, and even more preferably between 1.0 mm and 2.0 mm. The diameter of a wood pulp fiber is typically between 10 µm and 40 µm, preferably between 15 µm and 35 µm, and even more preferably between 20 µm and 30 µm. The aspect ratio (ratio between fiber length and diameter) of a wood pulp fiber is typically in the range of 7.5 to 350, preferably from 7.5 to 300, more preferably from 10 to 200, and even more preferably from 20 to 150. The terms “fiber” and “filament” may be used interchangeably for the purposes of the present invention unless specifically indicated otherwise.

[0040] The term “cellulose fiber base sheet” refers to a nonwoven fiber base sheet that has a structure of individual fibers that are interwoven, but not in a manner identifiable as in a woven or knitted fabric, wherein the nonwoven fiber base sheet is derived from or prepared from cellulose fibers. A cellulose fiber is a fiber composed substantially of cellulose. Nonwoven materials can be formed by various processes such as spinning, carding, air deposition, and wet deposition. The basis weight of nonwoven materials, such as a cellulose fiber base sheet, is generally expressed in weight per unit area, for example, in grams per square meter (gsm = g / m2) or ounces per square foot (ozf).

[0041] The cellulose fiber base sheet used in the present invention is preferably a wet-formed paper sheet.The cellulose fiber base sheets used in embodiments of the present invention are preferably cellulose fibers from natural sources (e.g., native cellulose fibers).

[0042] The term “native cellulose fibers” refers to cellulose fibers derived from natural sources, such as woody plants, including Petition 870260039395, dated 04 / 28 / 2026, page 16 / 68 11 / 49 deciduous and coniferous trees, or non-woody plants, including cotton, flax, esparto grass, kenaf, sisal, abaca, milkweed, straw, jute, hemp, and bagasse. The cellulose fibers may be unbleached or bleached cellulose fibers. Preferably, the native cellulosic fibers used in the present invention are derived from woody plants. Suitable fibers include, for example, eucalyptus fibers, birch fibers, or other annual plant fibers. The native cellulosic fibers form a crystalline material comprising a crystallized fraction with the crystalline form of Cellulose I, comprising parallel oriented cellulose chains.

[0043] Preferably, the cellulose fiber base sheet is a wood pulp paper sheet. The paper substrate used in the present invention preferably comprises natural hardwood fibers, more preferably eucalyptus fibers. Preferably, the paper substrate comprises hardwood fibers in an amount of 20% by weight or more, preferably 30% by weight or more, more preferably 40% by weight or more, and even more preferably 50% by weight or more relative to the total amount of fibers in the cellulose fiber base sheet. Adjusting the amount of hardwood fibers contributes to the paper density.

[0044] Furthermore, the paper substrate used in the present invention preferably comprises natural softwood fibers, which contribute to the mechanical strength of the paper. Preferably, the paper substrate comprises softwood fibers in an amount of 10% by weight or more, preferably 20% by weight or more, more preferably 30% by weight or more, and preferably 70% by weight or less, more preferably 60% by weight or less, and even more preferably 50% by weight or less relative to the total amount of fibers. Petition 870260039395, dated 04 / 28 / 2026, page 17 / 68 12 / 49 on the cellulose fiber base sheet.

[0045] In a preferred embodiment of the present invention, the paper substrate is made of natural cellulosic fibers, from the point of view of biodegradability. It is particularly preferable that the paper substrate be biodegradable. Thus, the paper substrate should preferably contain a maximum of 10% by weight of non-biodegradable or undetermined compostability material in order to meet the requirements of EN 13432. It is even more preferable that the paper substrate be more than 90% biodegradable, for example, more than 95%, more than 98%, more than 99% or 100% biodegradable, i.e., that the paper substrate contains less than 10% by weight, less than 5% by weight, less than 2% by weight, less than 1% by weight or 0% by weight of non-biodegradable material or undetermined compostability material. In a much more preferred embodiment, any additives added to the paper substrate are compostable.The paper substrate preferably comprises at least 50% by weight of cellulosic fibers, preferably at least 60% by weight of cellulosic fibers, more preferably at least 85% by weight of cellulosic fibers, and even more preferably at least 90% by weight of cellulosic fibers. In a more preferred embodiment, at least 95% by weight and, in a much more preferred manner, 100% by weight of the fibers in the paper substrate are natural cellulosic fibers.

[0046] The diameter of the cellulose fibers is preferably from 10 µm to 40 µm, more preferably from 15 µm to 35 µm, and even more preferably from 20 µm to 30 µm. The length of the cellulose fibers is preferably from 0.3 mm to 3.5 mm, more preferably from 0.3 mm to 3.0 mm, even more preferably from 0.8 mm to 2.5 mm, and most preferably from 1.0 mm to 2.0 mm. Therefore, the average aspect ratio (ratio between length and diameter of cellulose fibers) is in a way Petition 870260039395, dated 04 / 28 / 2026, p. 18 / 68 13 / 49 preferred from 7.5 to 350, more preferred from 7.5 to 300, even more preferred from 10 to 200, and most preferred from 20 to 150.

[0047] The paper substrate typically has an average thickness of 30 µm to 150 µm, preferably 40 µm to 120 µm, even more preferably 45 µm to 80 µm, and, most preferably, about 65 µm, from the point of view of obtaining excellent mechanical reinforcement properties.

[0048] Typically, the paper substrate does not contain fillers. In particular, the total amount of titanium dioxide, calcium carbonate, and clay in the paper substrate is preferably not more than 5% by weight, more preferably not more than 2% by weight, and even more preferably not more than 1% by weight. Preferably, the total amount of fillers in the paper substrate should not exceed 2% by weight, more preferably not more than 1% by weight, and even more preferably not more than 0.5% by weight.

[0049] Preferably, the cellulosic fibers described above are obtained by refining a pulp until the desired degree of refinement is reached (defined in this document as Schopper Riegler number, °SR). Preferably, the cellulosic fibers are refined to 30 °SR or more, more preferably to 35 °SR or more, more preferably to 40 °SR or more, even more preferably to 55 °SR or more, even more preferably to 60 °SR or more, and much more preferably to 65 °SR or more, and to 90 °SR or less, and even more preferably to 80 °SR or less as measured in accordance with ISO 5267.

[0050] The paper substrate preferably has an air transmittance of 10 ml / min or more, preferably 20 ml / min or more, most preferably 25 ml / min or more, Petition 870260039395, dated 04 / 28 / 2026, p. 19 / 68 14 / 49 even more preferably 30 ml / min or more, and 80 ml / min or less, preferably 75 ml / min or less, more preferably 70 ml / min or less, as determined in accordance with ISO 5636-3.

[0051] When the degree of refinement and air transmittance of the paper substrate are within the ranges mentioned above, good barrier and mechanical properties can be achieved in the final packaging material. In particular, this degree of refinement and air transmittance can be achieved by adjusting the pulp refinement during the production of the paper substrate. A very low air transmittance, such as below 20 ml / min, or a very high degree of refinement, such as above 90 °SR, indicates a high degree of paper refinement and may reduce its mechanical properties. The inventors of the present invention have found that a good balance in terms of mechanical properties and barrier performance can be achieved by controlling the refinement so that the degree of refinement / air transmittance is within the ranges described above.

[0052] The paper substrate should preferably have a Hagerty porosity greater than 6,500 s / 100 cm3. More preferably, the paper substrate has a Hagerty porosity greater than 10,000 s / 100 cm3, preferably greater than 20,000 s / 100 cm3, more preferably greater than 30,000 s / 100 cm3 and even more preferably greater than 50,000 s / 100 cm3. In addition, the paper substrate should preferably have a Hagerty porosity less than 10,000,000 s / 100 cm3. The Hagerty porosity is determined in accordance with ISO 5636-5, for example, in an automated PROFILE / Plus® roughness and porosity test system (from Technidyne). The inventors of the present invention observed that the MVTR is low when the coating according to the invention is applied to a base paper with high Hagerty porosity. When the Petition 870260039395, dated 04 / 28 / 2026, p. 20 / 68 15 / 49 If the Hagerty porosity of the paper substrate is within the limits mentioned above, the MVTR of the final packaging material will be further reduced.

[0053] Preferably, the paper substrate has a basis weight of 30 g / m2 or more, preferably 35 g / m2 or more, and even more preferably 40 g / m2 or more. In addition, the paper substrate preferably has a basis weight of 200 g / m2 or less, preferably 180 g / m2 or less, even more preferably 160 g / m2 or less, and even more preferably 150 g / m2 or less. Preferably, the paper substrate has a basis weight of 30 to 200 g / m2, even more preferably 40 to 200 g / m2; or, preferably, the paper substrate has a basis weight of 30 to 150 g / m2, even more preferably 40 to 150 g / m2. When the basis weight of the paper substrate is within the limits mentioned above, the mechanical properties of the final packaging material are improved.

[0054] In a preferred embodiment, the paper substrate is calendered and / or overcalendered. More specifically, the paper substrate can be calendered, overcalendered, or both. More preferably, the paper substrate is calendered and / or overcalendered before coating the base paper with the composition according to the invention. Even more preferably, the paper substrate is calendered and / or overcalendered after the optional pre-coating described below.

[0055] A preferred calendering step of the base paper in a method of manufacturing packaging material according to the present invention is described below. A calendered and / or overcalendered paper substrate can be advantageous in terms of improving the edge absorption effect (described below) of the packaging material and, consequently, improving its properties of Petition 870260039395, dated 04 / 28 / 2026, p. 21 / 68 16 / 49 grease resistance. For example, a calendering step can help obtain a denser packaging material, which can increase the grease barrier of the core material without negatively affecting the mechanical properties for conversion. In addition, a calendering step can improve the printability of the material.

[0056] Preferably, before coating or optional pre-coating of the base paper, the paper substrate should have a Sheffield surface smoothness / roughness of less than 600 Sheffield Units (SU), preferably less than 400 SU, more preferably less than 350 SU, and even more preferably less than 300 SU. In addition, the paper substrate should preferably have a Sheffield surface smoothness to roughness ratio greater than 100 SU. Sheffield surface smoothness / roughness is determined according to Tappi T538.When the paper substrate has a Sheffield smoothness-to-roughness ratio of less than 600 SU, the surface is considered very smooth. This allows for a reduction in the amount of coating compound needed to form a uniform layer over the entire surface of the paper substrate.

[0057] In a preferred embodiment, the packaging material of the present invention may comprise a paper substrate pre-coated with a composition that includes a grease barrier precursor. The term “pre-coated paper substrate,” as used herein, refers to a base paper that is pre-coated with said composition. The term “pre-coated with a composition,” as used herein, indicates that the composition penetrates the cavities of the paper substrate along at least part of the thickness of the paper substrate. Preferably, the composition penetrates the cavities of the paper substrate along its entire thickness. However, as the grease barrier properties Petition 870260039395, dated 04 / 28 / 2026, p. 22 / 68 17 / 49 Grease resistance can also be achieved with a pre-coating that does not penetrate the entire paper substrate but forms a film on the surface, allowing for the use of less material. A pre-coating on the surface of the paper substrate is beneficial in terms of the recyclability of the packaging material. Preferably, the composition pre-coats the paper substrate across its entire surface. The composition, which includes a grease barrier precursor, can also additionally coat a surface of the paper substrate. For efficient coating, the optional pre-coating is preferably carried out before calendering and / or overcalendering of the paper substrate, as described above.

[0058] In the context of the preferred embodiment of the present invention, the term “grease barrier precursor” refers to compounds that increase the grease resistance of a material containing them, compared to the same material without them. The inventors have surprisingly discovered that the grease barrier precursors, as described in this document, can increase the grease resistance of the paper substrate pre-coated with a composition containing them, compared to the base paper substrate before pre-coating. Furthermore, the grease barrier precursor decreases edge absorption of the pre-coated paper substrate by at least 10%, preferably by at least 20%, and even more preferably by at least 30%, compared to the non-pre-coated paper substrate, wherein edge absorption is determined as follows. (i) Two 10 x 10 cm samples were cut from test paper. The CD (cross direction) and MD (machine direction) directions were marked. (ii) The papers were rolled up to form a tube, held in place with a paper clip or staple. The paper at the bottom of the tube was not Petition 870260039395, dated 04 / 28 / 2026, page 23 / 68 18 / 49 must be overlapped to prevent capillary rise of the RP2 sauce between two layers of paper. (iii) 10 ml of colored RP2 solution (red-dyed synthetic oil supplied by Ralston-Purina) were added to a Petri dish under a fume hood. (iv) The paper tube was positioned vertically in the Petri dish so that the bottom edge touched the bottom of the Petri dish. The start of the contact time with the RP2 liquid was recorded. (v) The tube in the Petri dish was left in a fume hood at room temperature for 24 hours. (vi) After 24 hours, the paper sample was removed and pressed between two sheets of absorbent paper (1 reciprocating motion, standard 3 or 10 kg roll). (vii) The maximum total height reached by the RP2 simulant was measured in two samples, starting at the bottom of the paper.

[0059] In the preferred embodiment relating to a pre-coated paper substrate, the grease barrier precursor is selected from at least one of the group consisting of polysaccharides such as starch, a starch derivative, carboxymethylcellulose, carboxyethylcellulose, chitosan, alginate, dextrin, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and a mixture thereof. More preferably, the grease barrier precursor is starch, a starch derivative such as cationic, anionic, and non-ionic starch, carboxymethylcellulose, carboxyethylcellulose, chitosan, alginate, dextrin, or a mixture thereof. Much more preferably, the grease barrier precursor is cationic starch, anionic starch, carboxymethylcellulose, or a mixture thereof.

[0060] In the present invention, the term "cationic starch" denotes starch containing groups that are positively charged at pH 7, wherein said groups may be one or more selected from Petition 870260039395, dated 04 / 28 / 2026, page 24 / 68 19 / 49 amine groups, ammonium groups, imino groups, or phosphonium groups. In the present invention, "anionic starch" denotes starch containing groups that are negatively charged at pH 7, wherein such groups may be, for example, carboxylic groups. In the context of the present invention, cationic starch and anionic starch are particularly preferable as grease barrier precursors, both from the point of view of improving mechanical properties to meet pet food conversion requirements, and from the point of view of improving the grease barrier in the core of the material.

[0061] Advantageously, the preferred embodiment of pre-coating the base paper with the composition comprising the grease barrier precursor is to reduce the penetration of the coating layer, as described below. This can help minimize surface defects in the coating layer and thus reduce the formation of weak points through which grease can pass. Preferably, the grease barrier precursor is present in an amount less than 14% by weight, preferably less than 10% by weight, more preferably less than 5% by weight, and even more preferably less than 3% by weight relative to the paper substrate. In addition, the grease barrier precursor is present in an amount greater than 1% by weight and preferably greater than 2% by weight relative to the paper substrate.

[0062] In a further preferred embodiment, the pre-coated paper substrate represents 50% or more by weight, preferably 60% or more by weight, and most preferably 70% or more by weight, of the total weight of the packaging material. In addition, the pre-coated paper substrate represents, preferably, 99% or less by weight, preferably 95% or less by weight, and most preferably 90% or less by weight of the total weight of the packaging material. Petition 870260039395, dated 04 / 28 / 2026, page 25 / 68 20 / 49 Coating

[0063] The packaging material of the present invention comprises a paper substrate coated at least on the first or second side with a coating (hereinafter also referred to as the coating layer). The coating is applied to at least one side of the paper substrate described above and comprises a wax and a copolymer, as described below.

[0064] Preferably, the coating is applied to the entire surface, at least on the first or second side. In addition, in a preferred embodiment, the coating is applied to the first side, but not the second side of the paper substrate.

[0065] The coating layer on the packaging material of the present invention minimizes defects on the surface of the paper substrate and ensures a low MVTR, as described in detail below, as well as high grease resistance.

[0066] Preferably, the coating comprising the wax and copolymer is present in an amount of no more than 25% by weight, more preferably no more than 20% by weight, and even more preferably no more than 15% by weight, based on the paper substrate and the coating. Preferably, the coating comprising the wax and copolymer is present in an amount of at least 1% by weight, more preferably at least 5% by weight, based on the paper substrate and the coating. An amount of coating within the ranges mentioned above is advantageous as it improves the recyclability of the packaging material while ensuring good barrier properties and low MVTR.

[0067] The basis weight of the coating layer is preferably 4.0 g / m2 or more, preferably 4.5 g / m2 or more, most preferably 5.0 g / m2 or more, most preferably Petition 870260039395, dated 04 / 28 / 2026, p. 26 / 68 21 / 49 preferred of 5.5 g / m2 or more, and of 25 g / m2 or less, preferably 20 g / m2 or less, and most preferably 15 g / m2 or less. A weight per unit area within the above ranges is advantageous as it improves the barrier properties and low MVTR of the packaging material, while still ensuring good recyclability and without incurring a blocking effect.

[0068] In the present invention, the coating comprises a wax. The term “wax,” as used in this document, has its common meaning for persons skilled in the art. That is, the term “wax” refers to organic compounds distinguished by being composed of acid esters with long aliphatic hydrocarbon chains. The total amount of wax in the coating layer can preferably be 40% by weight or less, more preferably 35% by weight or less, and even more preferably 30% by weight or less. In addition, the total amount of wax in the coating layer can preferably be 1% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, and much more preferably 15% by weight or more relative to the total amount of the coating.

[0069] Wax can be natural, synthetic, or a mixture of both. Natural waxes may contain unsaturated bonds and various functional groups, such as fatty acids, primary and secondary alcohols, ketones, aldehydes, and fatty acid esters. Natural waxes include waxes derived from beeswax, epicuticular plant waxes such as carnauba wax, jojoba oil, candelilla wax, rice bran oil, and ouricuri wax. Synthetic waxes may be composed of long-chain aliphatic hydrocarbons (alkanes or paraffins), preferably not comprising functional groups. Synthetic waxes include paraffin. Petition 870260039395, dated 04 / 28 / 2026, p. 27 / 68 22 / 49

[0070] The wax according to the present invention is preferably at least one selected from at least one of the group consisting of beeswax, carnauba wax or paraffin. More preferably, the wax is paraffin.

[0071] In the present invention, the coating further comprises a copolymer selected from at least one of the group consisting of a styrene-butadiene copolymer and a styrene-acrylic copolymer. The total amount of a copolymer selected from styrene-butadiene copolymer and styrene-acrylic copolymer in the coating layer may preferably be 60 to 90% by weight, and more preferably 65 to 85% by weight relative to the total amount of the coating.

[0072] Styrene-butadiene copolymer is a polymer derived from the polymerization of a styrene monomer and a butadiene monomer. Preferably, the styrene-butadiene copolymer should be at least one selected from a styrene-butadiene rubber latex and a styrene-butadiene rubber obtained by emulsion polymerization or solution polymerization.

[0073] Styrene acrylic copolymer is a polymer derived from the polymerization of a styrene monomer with an acrylic ester monomer and / or an acrylic acid monomer. Preferably, styrene-acrylic copolymer is a water-based styrene-acrylic emulsion polymer obtained by emulsion polymerization.

[0074] In one embodiment of the invention, the coating may comprise one or more additional polymers selected from polyvinyl alcohol, starch, polyurethane, ethylene-vinyl acetate copolymer, styrene (meth)acrylic acid copolymer, and poly(meth)acrylic acid. That is, the coating layer may comprise one or more polymers. When the coating layer comprises more than one polymer, it may be described in this document as comprising Petition 870260039395, dated 04 / 28 / 2026, page 28 / 68 23 / 49 a “polymer mixture”. The total amount of the polymer mixture in the coating layer may be from 1 to 15% by weight or more, and preferably from 2 to 10% by weight or more relative to the total amount of the coating. Furthermore, the amount of the polymer mixture in the coating layer may be from 2 to 30% by weight or less, and more preferably from 4 to 20% by weight or less relative to the total amount of the coating.

[0075] In a preferred embodiment, the coating layer may further comprise a filler selected from calcium carbonate, clay, talc, and a mixture thereof. Most preferably, the filler is calcium carbonate. When a filler is present, the amount thereof may be 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, and even more preferably 20% by weight or more relative to the total amount of components of the coating layer. Furthermore, when present, the amount of filler may be 60% by weight or less, preferably 55% by weight or less, more preferably 50% by weight or less, and even more preferably 45% by weight or less relative to the total amount of components of the coating layer.The inclusion of a filler in the coating layer can be advantageous as it improves drying and reduces foam formation in the coating layer, without negatively affecting barrier properties.

[0076] Figure 2 is a schematic illustration of a preferred embodiment in which a filler is comprised within the coating layer. As shown in Figure 2, in such embodiment, the packaging material (2) comprises a paper substrate (20) which is optionally pre-coated with a grease barrier precursor (22), the paper substrate (20) being coated on a first side with a coating (21) comprising a filler (24) in addition to a Petition 870260039395, dated 04 / 28 / 2026, page 29 / 68 24 / 49 wax and a copolymer (23) selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer.

[0077] The coating layer of the packaging material of the present invention may comprise additional components, such as antifoaming agents, thickeners such as carboxymethylcellulose and / or crosslinking agents such as glyoxal-based compounds.

[0078] In a preferred embodiment of the present invention, the packaging material may further comprise an additional coating layer applied over the coating layer, which comprises a wax and a copolymer, as described below. In the context of the present invention, when an additional coating layer is present, the coating layer applied over the paper substrate may be referred to as the “first coating layer” and the additional coating layer may be referred to as the “second coating layer”.

[0079] Figure 3 is a schematic illustration of a preferred embodiment, in which a second coating layer is present and applied over the first coating layer. As shown in Figure 3, the packaging material (3) of such embodiment comprises a paper substrate (30), which is optionally pre-coated with a grease barrier precursor (32), the paper substrate (30) being coated on a first side with a first coating (31) comprising wax and a copolymer (33) selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer, and the first coating (31) being coated with a second coating (34) comprising wax and a copolymer (35) selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer.

[0080] When a second coating layer is present according to the preferred embodiment of the present invention, the Petition 870260039395, dated 04 / 28 / 2026, p. 30 / 68 25 / 49 polymer(s), the optional filler and optional additional components contained in said second coating layer may be the same as or different from the polymer(s) described above that may be contained in the first coating layer. That is, the composition of the second coating layer and that of the first coating layer may be the same as or different from each other. The presence of a second coating layer may be advantageous in terms of improving the MVTR and grease barrier properties of the final packaging material.

[0081] In the preferred embodiment of the present invention, the second coating layer preferably represents a maximum of 12.5% ​​by weight, or more preferably 10% by weight, based on the paper substrate and coating. Preferredly, the total amount of the first coating layer and the optional second coating layer in the packaging material is a maximum of 25% by weight, or more preferably a maximum of 20% by weight, and a minimum of 1% by weight, or more preferably a minimum of 5% by weight, based on the paper substrate and coating. The basis weight of the second coating layer is preferably 8 g / m² or less; or more preferably 7 g / m² or less.

[0082] Preferably, the basis weight of all coating layers in the packaging material is 4.0 g / m2 or more, preferably 4.5 g / m2 or more, more preferably 5.0 g / m2 or more, more preferably 5.5 g / m2 or more, and 25 g / m2 or less, preferably 20 g / m2 or less, more preferably 15 g / m2 or less. A weight per unit area within the above ranges is preferable from the point of view of the MVTR and barrier properties of the packaging material, while still ensuring good recyclability and without incurring a blocking effect.

[0083] In particular, the use of a first layer of Petition 870260039395, dated 04 / 28 / 2026, p. 31 / 68 26 / 49 coating and a second coating layer, according to the preferred embodiment of the present invention, can further improve the MVTR and grease barrier properties compared to using a single coating layer with the same basis weight. Without wanting to be tied to any theory, it is believed that the reason for this may be that the use of two lighter coating layers, instead of a single heavier layer, allows for the masking of surface imperfections that may arise in the first layer and compensates for weak points through which grease may pass. With two layers, the probability of such defects can be reduced. These effects can be observed even when the first and second coating layers have the same composition but were deposited in two consecutive coating steps.

[0084] In a further preferred embodiment, in the packaging material of the present invention, the coating is applied to one side of the paper substrate, and the packaging material further comprises a printing layer applied to the other side of the paper substrate. Specifically, the coating is preferably applied to the first side of the paper substrate, but not to the second side, and a printing layer is applied to the other side of the paper substrate. Preferably, the printing layer is applied over the entire surface of the other side of the paper substrate.

[0085] Figure 4 illustrates a preferred embodiment of the present invention, in which a printing layer is present. As shown in Figure 4, the packaging material (4) comprises a paper substrate (40), which is optionally pre-coated with a grease barrier precursor (42), the paper substrate (40) being coated on a first side with a first coating (41) comprising wax and a copolymer (43) selected from copolymer Petition 870260039395, dated 04 / 28 / 2026, page 32 / 68 27 / 49 of styrene-butadiene and / or styrene-acrylic copolymer, and the paper substrate (40) being coated on a second side with a printing layer (44).

[0086] Furthermore, as shown in Figure 5, in a preferred embodiment, the packaging material (5) may comprise, in addition to the printing layer (56) coated on a second side of the paper substrate (50), also an additional coating layer (54) coated over the coating layer (51), which in turn is coated on a first side of the paper substrate (50). The coating layers (51, 54) each independently comprise wax and a copolymer (53, 55) selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer. That is, the preferred embodiment described above, in which an additional coating layer is present, may further comprise a printing layer. The properties and components of the additional coating layer are as described above for the embodiment comprising an additional coating layer.In addition, the extra coating layer may also include a filler, as described above.

[0087] In a further preferred embodiment, the printing layer preferably comprises a binder selected from styrene-butadiene-based binders (such as Styronal D 517 F produced by BASF, or L7066 from EOC), styrene-acrylic-based binders (such as Acronal S360D from BASF), starch, or starch derivative, or carboxymethylcellulose, or a mixture thereof. The amount of binder in the printing layer is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more and 60% by weight or less, preferably 50% by weight or less, and most preferably 40% by weight or less. Petition 870260039395, dated 04 / 28 / 2026, p. 33 / 68 28 / 49 less in relation to the total number of components in the printing layer.

[0088] In a further preferred embodiment, the printing layer preferably comprises a filler selected from calcium carbonate, clay, talc, and a mixture thereof. The amount of filler in the printing layer is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more and 90% by weight or less, preferably 85% by weight or less, and most preferably 80% by weight or less relative to the total amount of components in the printing layer.

[0089] In a further preferred embodiment, the printing layer may comprise other additives, such as antifoaming agents, dispersants, lubricants, crosslinking agents, thickeners, pH modifiers and gloss enhancers.

[0090] When present, the printing layer may represent 1% by weight or more, preferably 2% by weight or more, more preferably 4% by weight or more, and 12% by weight or less, preferably 10% by weight or less, and even more preferably 8% by weight or less of the total weight of the packaging material.

[0091] When a printing layer is present, its base weight may be 1 g / m2 or more, preferably 2 g / m2 or more, more preferably 3 g / m2 or more, and 10 g / m2 or less, preferably 8 g / m2 or less, more preferably 6 g / m2 or less.

[0092] One of the objectives of the present invention is to provide a packaging material that exhibits an ideal balance between mechanical properties, MVTR and grease barrier properties, while reducing the amount of per- and polyfluoroalkylated substances in the Petition 870260039395, dated 04 / 28 / 2026, p. 34 / 68 29 / 49 packaging material, which are conventionally used to improve barrier properties against grease.

[0093] In particular, the total amount of fluorine-containing organic substances (including per- and polyfluoroalkyl substances) in the packaging material of the present invention does not exceed 20 ppm, preferably 15 ppm, more preferably 10 ppm and, even more preferably, 5 ppm, based on the total weight of the packaging material.

[0094] In a further preferred embodiment, the total amount of elemental fluorine in the packaging material, i.e., the fluorine content, does not exceed 100 ppm, preferably does not exceed 90 ppm, and more preferably does not exceed 80 ppm, based on the total weight of the packaging material. Specifically, the packaging material according to this preferred embodiment has a fluorine content of less than 100 ppm, preferably less than 90 ppm, and more preferably less than 80 ppm.

[0095] In the present invention, in a preferred embodiment, the amount of standard sizing agents is limited. Examples of sizing agents include alkyl ketene dimers, soap resin, anionic resin, and cationic resin. It has been found that keeping the amount of these sizing agents below a certain limit facilitates the penetration of the grease barrier precursor into the paper substrate. This results in an improvement in the grease barrier properties of the paper substrate, which can be achieved without the use of per- and polyfluoroalkyl substances. When these sizing agents are present in large quantities in the paper substrate, they can interfere with the penetration of the grease barrier precursor into the paper and affect the performance of this barrier. More specifically, in the present invention, the total amount of alkyl ketene dimers, soap resin, anionic resin, and cationic resin in the paper substrate is, of Petition 870260039395, dated 04 / 28 / 2026, p. 35 / 68 30 / 49 a preferred mode, less than 2.0% by weight, a more preferred mode less than 1.5% by weight, a more preferred mode less than 1.0% by weight and a still more preferred mode less than 0.5% by weight, based on the total weight of the paper substrate. Preferredly, the total amount of binding agents in the paper substrate is less than 2.0% by weight, a preferred mode less than 1.5% by weight, a more preferred mode less than 1.0% by weight and a still more preferred mode less than 0.5% by weight, based on the total weight of the paper substrate.

[0096] Furthermore, in the present invention, it is preferable that the amount of moisture-resistant agents also be limited. Examples of moisture-resistant agents include polyamidoamine-epichlorohydrin resin, polyethyleneimine, urea-formaldehyde, and melamine-formaldehyde resins. Preferably, in the present invention, the total amount of polyamidoamine-epichlorohydrin resin, polyethyleneimine, urea-formaldehyde, and melamine-formaldehyde in the paper substrate is less than 0.5% by weight, more preferably less than 0.35% by weight, and even more preferably less than 0.2% by weight, based on the total weight of the paper substrate. Preferably, the total amount of moisture-resistant agents in the paper substrate is less than 0.5% by weight, preferably less than 0.35% by weight, and most preferably less than 0.2% by weight, based on the total weight of the paper substrate.

[0097] In a preferred embodiment, the total amount of alkyl ketene dimers, soap resin, anionic resin, cationic resin, polyamidoamine-epichlorohydrin resin, polyethyleneimine, urea-formaldehyde resin and melamine-formaldehyde resin is less than 0.5% by weight, preferably less than 0.35% by weight and, more preferably, less than 0.2% by weight, based on the total weight of the paper substrate. Petition 870260039395, dated 04 / 28 / 2026, page 36 / 68 31 / 49

[0098] In a more preferred embodiment, the total amount of sizing agents and moisture-resistant agents is less than 0.5% by weight, preferably less than 0.35% by weight and, most preferably, less than 0.2% by weight, based on the total weight of the paper substrate.

[0099] In a preferred embodiment, the amount of polyethylene and polypropylene is less than 0.5% by weight, preferably less than 0.3% by weight and, most preferably, less than 0.2% by weight, based on the total weight of the packaging material.

[00100] Preferably, the amount of plastic film in the packaging material is less than 0.5% by weight, preferably less than 0.3% by weight and, most preferably, less than 0.2% by weight, based on the total weight of the packaging material. Physical and mechanical properties

[00101] The base weight of the packaging material according to the present invention is preferably 40 g / m2 or more, more preferably 50 g / m2 or more, even more preferably 60 g / m2 or more, and even more preferably 70 g / m2 or more. Furthermore, the base weight of the packaging material according to the present invention is preferably 220 g / m2 or less, more preferably 130 g / m2 or less, even more preferably 120 g / m2 or less, even more preferably 110 g / m2 or less, and, most preferably, 100 g / m2 or less.

[00102] The Sheffield surface smoothness / roughness of the packaging material according to the present invention is preferably less than 200 SU, more preferably less than 150 SU and even more preferably less than 100 SU, when determined in accordance with Tappi T538 standard, as described above.

[00103] The thickness of the packaging material according to Petition 870260039395, dated 04 / 28 / 2026, p. 37 / 68 32 / 49 The present invention is preferably 50 pm or more, preferably 55 pm or more, more preferably 60 pm or more, even more preferably 70 pm or more, and 120 pm or less, preferably 110 pm or less, more preferably 100 pm or less, and even more preferably 95 pm or less.

[00104] A tensile strength in the machine direction (MD) of the packaging material of the present invention, as determined by ISO 1924, is 1 kN / m or more, preferably 2 kN / m or more, more preferably 3 kN / m or more, even more preferably 3.5 kN / m or more, and 12 kN / m or less, preferably 10 kN / m or less, even more preferably 8 kN / m or less.

[00105] A tensile strength in the transverse direction (CD) of the packaging material of the present invention, as determined by ISO 1924, is preferably 0.5 kN / m or more, more preferably 1 kN / m or more, even more preferably 1.5 kN / m or more, and 8 kN / m or less, more preferably 7 kN / m or less, even more preferably 6 kN / m or less.

[00106] Adjusting the tensile strength in MD and / or CD within the above ranges further improves mechanical strength, resulting in greater resistance to handling, especially when the packaging material is intended to contain heavy items. Recyclability

[00107] Preferably, the packaging material of the present invention is recyclable by repulping and recoverable according to EN 13430 by at least 85% by weight. The term “repulping” describes a process in which a material that has already undergone or been formed by at least one pulping step is subjected to a new step. Petition 870260039395, dated 04 / 28 / 2026, p. 38 / 68 33 / 49 of pulping. The term “recyclable by repulping” describes a material that can be, at least partially, recovered and converted into a new material or object during a repulping step. This material may be a waste product. The term “recyclable” is generally described according to the EN 13430 standard. The expression “recyclable by repulping and recoverable according to EN 13430 by at least 85%” therefore describes a material that has been formed by, or otherwise subjected to, at least one pulping step and from which, when subjected to a further pulping step, at least 85% by weight of the material can be recovered. In a preferred embodiment, the packaging material is recyclable by repulping and recoverable according to EN 13430 by at least 90% by weight, and in a still more preferred way by at least 95% by weight. Compliance with food contact standards

[00108] The packaging material of the present invention is a food packaging material, which means that it is suitable as a food packaging material. Preferably, the packaging material of the present invention is a pet food packaging material.

[00109] In one embodiment, the packaging material is approved for food contact in accordance with any of the following standards: Regulation EC 1935 / 2004, BfR 36, FDA 21 CFA §176-170 and 176-180. Barrier properties

[00110] In the present invention, the packaging material comprises a paper substrate coated at least on the first or second side with a coating. The coating layer on the packaging material is composed of a wax and a copolymer, as described above, and allows minimizing defects on the surface of the paper substrate and ensuring a low MVTR, thus achieving Petition 870260039395, dated 04 / 28 / 2026, p. 39 / 68 34 / 49 excellent vapor barrier properties and ensuring high grease resistance. By using a pre-coated paper substrate according to a preferred embodiment of the invention, as described above, the grease resistance of the paper substrate is increased. This can be useful for packaging food products, such as pet food, which are known to have a high fat content.

[00111] In a preferred embodiment, the packaging material has a moisture vapor transmission rate (MVTR) of less than 75 g / m2 / 24h, preferably less than 50 g / m2 / 24h, more preferably less than 35 g / m2 / 24h or less, even more preferably less than 30 g / m2 / 24h or less, and much more preferably less than 25 g / m2 / 24h or less, determined at 85% relative humidity and 23 °C. MVTR is determined in accordance with ISO 2528.

[00112] MVTR is an indication of the permeability of water vapor through a substance. A low MVTR indicates an improved vapor barrier. In food packaging, moisture control is crucial for maintaining food quality, ensuring its safety, and extending its shelf life. MVTR generally decreases with increasing thickness of the barrier coating layer and increases with increasing temperature. The food packaging material according to the present invention, however, exhibits improved MVTR (more specifically, lower MVTR) compared to other materials comprising a coating layer that does not comprise a wax and a copolymer, as described above. The packaging material of the present invention is therefore capable of controlling the moisture of packaged products, thereby extending the shelf life of moisture-sensitive food products.

[00113] In another preferred embodiment, the packaging material has a Cobb in 30 minutes measured according to TAPPI 441 lower Petition 870260039395, dated 04 / 28 / 2026, p. 40 / 68 35 / 49 to 10 g / m2, preferably less than 8 g / m2, more preferably less than 5 g / m2. The Cobb value indicates the amount of water absorbed by a defined area of ​​a paper sample through one-sided contact with water, within a given period of time (60 seconds, according to ISO 535). A higher Cobb value indicates greater water absorption and therefore lower barrier activity.

[00114] Preferably, the packaging material should be grease-resistant, in accordance with TAPPI T454. In one embodiment, the packaging material is grease-resistant, as determined by TAPPI T454, with 30 seconds no grease leakage, preferably with 60 seconds no leakage, more preferably with 180 seconds no leakage, more preferably with 300 seconds no leakage, more preferably with 600 seconds no leakage, and even more preferably with 1800 seconds no leakage. Food packaging

[00115] The food packaging material of the present invention can form a food package. As the food package is formed from the packaging material described above, a package with low MVTR is obtained, thus extending the shelf life of moisture-sensitive food products, maintaining ideal mechanical properties without the introduction of plastic films and / or papers containing fluorinated compounds. The food package of the invention is therefore safe for contact with food and has a lower environmental impact (i.e., greater recyclability). Method for producing a packaging material

[00116] Preferably, the packaging material of the present invention described above can be obtained by the packaging material production method according to the present invention and Petition 870260039395, dated 04 / 28 / 2026, page 41 / 68 36 / 49 described in this document.

[00117] A method for manufacturing the food packaging material of the present invention includes a coating layer application step as described above. On an industrial scale, the coating is applied to the paper substrate by direct rotogravure or using a single bar or by curtain coating or by spray coating or by press coating or by air blade coating or by flexographic coating to the paper substrate described above.

[00118] Specifically, the coating layer comprising wax and a copolymer selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer, according to the present invention, is applied to the paper substrate by at least one of the following methods: direct rotogravure, using a single bar, curtain coating, spray coating, press-on coating, air foil coating and flexographic coating.

[00119] The coating layer can be applied at a speed of 50 m / min or more, preferably 60 m / min or more, more preferably 80 m / min or more, even more preferably 100 m / min or more, and 1000 m / min or less, preferably 900 m / min or less, and most preferably 800 m / min or less.

[00120] Preferably, the coating is applied to the entire surface, at least on the first or second side. In addition, in a preferred embodiment, the coating is applied only to the first side, and not the second side, of the paper substrate.

[00121] In the method according to the invention, the components of the coating layer can be dispersed or dissolved in a liquid medium. The liquid medium used to disperse or dissolve the Petition 870260039395, dated 04 / 28 / 2026, p. 42 / 68 37 / 49 of the coating layer components is, preferably, water.

[00122] The coating layer application step can be performed by applying a composition comprising the coating layer components as described above. Specifically, the coating components comprise wax and copolymer selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer, as described above. In addition, the coating may comprise one or more additional polymers, fillers, defoamers, thickeners, and any component as described above for the coating layer of the packaging material of the present invention.

[00123] A method for manufacturing food packaging material according to the present invention may further comprise the following steps: (i) provide a paper substrate that has a first side and a second side, the second side being opposite the first side; (ii) optionally, pre-coat the paper substrate with a composition comprising a grease barrier precursor, as described above; and (iii) apply a coating layer comprising wax and a copolymer selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer at least to the first or second side of the optionally pre-coated paper substrate.

[00124] The method according to the present invention includes a step (i) of providing a paper substrate with a first side and a second side. The paper substrate may be as described above for the paper substrate prior to an optional pre-coating of the packaging material of the present invention.

[00125] The paper substrate preferably has a value Petition 870260039395, dated 04 / 28 / 2026, page 43 / 68 38 / 49 Cobb, measured according to ISO 535 standard, measured on the first and / or second side, of 30 g / m2 or more, preferably 35 g / m2 or more, more preferably 40 g / m2 or more, and 130 g / m2 or less, preferably 120 g / m2 or less, more preferably 100 g / m2 or less, and even more preferably 90 g / m2 or less. Adjusting the Cobb value within these ranges further improves efficient pre-coating with the grease barrier precursor in optional step (ii).

[00126] The method of the present invention includes an optional step (ii) of pre-coating the paper substrate with a composition comprising a grease barrier precursor. The grease barrier precursor comprised in the composition used in step (ii) may be as described above for the grease barrier precursor in the packaging material of the present invention.

[00127] In the method of the present invention, the composition used in the pre-coating step is preferably a composition in which the grease barrier precursor, as described above, is dispersed or dissolved in a liquid medium. The liquid medium used to disperse or dissolve the grease barrier precursor may be an aqueous medium and is preferably water.

[00128] Pre-coating can be carried out by any means known in the art and is preferably done by a sizing press, or by a metering sizing press or a sizing press with a flooded contact zone. For example, pre-coating can be carried out by a two-step method, including a step of adding a composition comprising a grease barrier precursor at the wet end and a further step of pre-coating the paper substrate by sizing press with a composition comprising a grease barrier precursor, which may be the same as or different from that used at the wet end. Petition 870260039395, dated 04 / 28 / 2026, page 44 / 68 39 / 49 For example, the grease barrier precursor added at the wet end may be cationic starch and / or carboxymethylcellulose, and the grease barrier precursor added at the sizing press may be anionic starch. Advantageously, pre-coating with the composition comprising the grease barrier precursor can be carried out directly on the paper machine, without the need for a converting step.

[00129] The method according to the present invention may include a step (ii') of calendering the optionally pre-coated paper substrate after step (ii) and / or a step (iii') of calendering the optionally pre-coated paper substrate coated with the coating layer after step (iii).

[00130] The inclusion of a calendering step (ii') and / or (iii') may be advantageous in terms of improving the edge absorption effect of the packaging material and thus improving its grease resistance properties. For example, a calendering step may help to obtain a denser packaging material, which may increase the grease barrier of the core material without negatively affecting the mechanical properties for conversion. In addition, a calendering step may improve the printability of the material.

[00131] The optional calendering step (ii') and / or (iii') can be performed by a soft calender, hard calender, shoe calender or supercalender. The number of calendering contact zones can vary from 1 to 16. This step is preferably performed by a soft calender with 4 pins, installed directly on the paper machine.

[00132] The method according to the present invention may include a step (iv) of applying an additional coating layer over the coating layer obtained in step (iii) and optionally calendered in step (iii'). The additional coating layer may be Petition 870260039395, dated 04 / 28 / 2026, page 45 / 68 40 / 49 as described above for the additional coating layer of the packaging material of the present invention. As described above, the additional coating layer may be referred to as the “second coating layer” and the coating layer over which the additional coating layer is applied may be referred to as the “first coating layer”.

[00133] Step (iv) of applying said second coating layer may be carried out in the same manner as step (iii) of applying the coating layer to the optionally pre-coated paper substrate.

[00134] Preferably, before applying the second coating layer in step (iv), a drying step (iii'') is performed on the first coating layer obtained in step (iii). A drying step (iv') on the second coating layer after step (iv) can also be performed.

[00135] The advantages of applying a second coating layer are those described above for the second coating layer of the packaging material of the present invention. These advantages can be observed even when the second coating layer optionally added in step (iv) has the same composition as the first coating layer applied in step (iii).

[00136] The method according to the present invention may further include a step (v) of applying a printing layer to the second side of the optionally pre-coated paper substrate. The printing layer may be as described above. Step (v) may be performed by any method known in the art for applying a printing layer to paper-based packaging materials and may preferably be applied by foil coating, liquid application system or rotogravure coating. Petition 870260039395, dated 04 / 28 / 2026, pp. 46 / 68 41 / 49 EXAMPLES

[00137] The following base papers (properties presented in Table 1) were used as paper substrates and coated with one or more of the coating compositions presented in Table 2, thus forming one or more coating layers for the manufacture of packaging materials.

[00138] By way of example, by coating the “paper substrate 1” with the “coating composition A” to provide a “first coating layer”, a packaging material comprising a single coating layer is obtained, which will be referred to as “sample 1-A” hereafter. By coating “sample 1-A” again with the “coating composition A” to provide a “second coating layer”, a packaging material with two coating layers is obtained, which will be referred to as “sample 1-AA” hereafter. Paper substrate 1

[00139] Base paper composed of 55% short fibers (hardwood) and 45% long fibers (conifers), pre-coated with 5% by weight starch, sizing with 1.2% alkyl ketene dimer (AKD) and calendered. The fibers were refined at 55-60° SR. Paper substrate 2

[00140] Base paper composed of 64% short fibers (hardwood) and 36% long fibers (coniferous), calendered and sized with 0.3 AKD. The fibers were refined at 30-40° SR to produce a more porous paper. Paper substrate 3

[00141] Base paper composed of 15% short fibers (hardwood) and 85% long fibers (conifers) and 0.8% by weight of TiO2 relative to the total amount of fibers, pre-coated with 1.5% by weight of starch and then calendered without sizing. The fibers were refined at 6070° SR. Petition 870260039395, dated 04 / 28 / 2026, page 47 / 68 42 / 49 Paper substrate 4

[00142] Base paper composed of 33% short fibers (hardwood), 67% long fibers (coniferous) and 1.7% by weight of TiO2 relative to the total amount of fibers, and pre-coated with 5% by weight of starch. The fibers are refined at 50-55° SR. The paper is then supercalendered. Paper substrate 5

[00143] Base paper composed of 20% short fibers (hardwood) and 80% long fibers (coniferous). The fibers are refined at 55-60° SR. This base paper is pre-coated with 5% by weight of starch and then undergoes a supercalendering process. Table 1: Properties of paper substrates Paper substrate Grammage [g / m2] Paper density [kg / m3] Porosity Hagerty* [sec] 1 52 968 34,800 2 44 690 290 3 66 928 8,300,000 4 65 1120 7,800 5 65 1120 73,900 *Hagerty porosity was measured on the Technidyne PROFILE / Plus® automated roughness and porosity testing system, in accordance with ISO 5636-5. Table 2: Coating compositions for forming coating layer(s) Coating composition Product name Chemical composition A EXCEVAL AQ 4104[1] polyvinyl alcohol (90 parts) Aquapel J220[2] alkyl ketene dimer (5 parts) Kymène[3] polyamide-epichlorohydrin (5 parts) B GENFLO 5086[4] styrene butadiene C COAT 252 ECO[5] styrene butadiene + wax Petition 870260039395, dated April 28, 2026, pp. 48-68 43 / 49 D Joncryl HPB 1634[6] styrene acrylic emulsion (partially based on renewable resources) + wax E WÜKOSEAL 1512[7] styrene-butadiene-based latex + wax F Joncryl HPB1631-A[8] styrene acrylic emulsion + wax Supplier: [1] Kuraray; [2·3] Solenis; [4] OMNOVA; [5] CHT; [6-8] BASF; [7] MUNZING Example 1

[00144] All materials in Example 1 are prepared using a laboratory-scale hand applicator.

[00145] A coating was applied to the first side of Paper Substrate 1, with the coating basis weight shown below in Table 3, using a hand applicator. Coating Compositions A, B, C, D, and E were used for the application of the first coating layer in the manufacture of Packaging Materials 1-A, 1-B, 1-C, 1-D, and 1-E.

[00146] Packaging Material 1-AA was manufactured by applying a layer of Coating Composition A to the first side of Paper Substrate 1. After the first coating layer dried, a second layer of Coating Composition A was applied over the first layer. Both coating layers were applied with the basis weight shown in Table 3 below, using a hand applicator.

[00147] The MVTR value of the samples prepared in Example 1 was determined as described above and the results are also shown in Table 3. Table 3: Packaging material 1 Packaging material Coating weight [g / m2] MVTR [g / m2 / 24h] 1-A 5.5 356 Petition 870260039395, dated 04 / 28 / 2026, pp. 49 / 68 44 / 49 Packaging material Coating weight [g / m2] MVTR [g / m2 / 24h] 1-AA 4.0 + 1.8 248 1-B 6.2 216 1-C 6.0 19 1-D 6.0 25 1-E 6.0 18.5

[00148] As can be seen in Table 3, the MVTR is very high for Packaging Material 1-A, which does not contain styrene copolymer or wax in the coating. Although an improvement in moisture barrier properties is observed for sample 1-AA, which has two coating layers without styrene copolymer or wax in the coating, the MVTR is only slightly reduced. MVTR is also high for Packaging Material 1-B, which contains a styrene copolymer but does not contain wax in the coating.

[00149] Packaging Materials 1-C, 1-D and 1-E, which contain wax and a styrene copolymer, however, exhibit a very low MVTR. The packaging materials according to the present invention therefore provide satisfactory moisture barrier properties, in addition to being recyclable. As discussed above, the addition of wax to the styrene copolymer results in a particularly suitable interaction within the coating, which improves the moisture barrier properties. Example 2

[00150] All materials in Example 2 are prepared using a laboratory-scale hand applicator.

[00151] A coating was applied to the first face of Paper Substrate 2, with the coating basis weight shown below in Table 4, using a hand applicator. Coating Compositions A, B, C, and D were used for the application of the first coating layer in the manufacture of Packaging Materials 2-A, 2-B, 2-C, and 2-D. Petition 870260039395, dated 04 / 28 / 2026, pp. 50 / 68 45 / 49

[00152] The MVTR value of the samples prepared in Example 2 was determined as described above and the results are also shown in Table 4. Table 4: Packaging material 2 Packaging material Coating weight [g / m2] MVTR [g / m2 / 24h] 2-A 5.7 422 2-B 6.1 159 2-D 5.7 56

[00153] As can be seen in Table 4, the MVTRs of the samples in Example 2 are, in general, higher when compared to those of Example 1, presented in Table 3. This results from the fact that paper substrate 2 has a more open structure and a significantly lower Hagerty porosity compared to Paper Substrate 1.

[00154] As shown in Table 4, the MVTR is very high for Packaging Material 2-A, which does not contain styrene copolymer or wax in the coating. Packaging Material 2-B, which contains a styrene copolymer but no wax in the coating, still exhibits a high MVTR.

[00155] Despite the open structure of Paper Substrate 2, Packaging Material 2-D, which contains wax and a styrene copolymer in the coating, provides satisfactory moisture barrier properties. Example 3

[00156] The materials in Example 3 are prepared using a manual applicator (also called a drawdown) on a laboratory scale or by means of machine tests, according to the methods indicated in Table 5.

[00157] A coating was applied to the first side of Paper Substrate 3, with the coating basis weight shown below in Petition 870260039395, dated 04 / 28 / 2026, pp. 51 / 68 46 / 49 Table 5. Coating Compositions A, B, D, and F were used for the application of the first coating layer in the manufacture of Packaging Materials 3-A, 3-B, 3-D, and 3-Faa 3-Fd. Materials 3-Faa 3-Fd are obtained through machine testing.

[00158] Packaging Material 3-AA was manufactured by applying a layer of Coating Composition A to the first side of Paper Substrate 3. After the first coating layer dried, a second layer of Coating Composition A was applied over the first layer. Both coatings were applied with the basis weight shown in Table 5 below, using a hand applicator.

[00159] The MVTR value of the samples prepared in Example 3 was determined as described above and the results are also shown in Table 5. Table 5: Packaging material 3 Packaging Material Coating Method Coating Grammage [g / m2] MVTR [g / m2 / 24h] 3-A manual applicator 5.7 341 3-AA manual applicator 4.3 + 2.0 222 3-B manual applicator 6.2 320 3-D manual applicator 6.3 28 3-Fa drawdown type application bar 13.0 22 3-Fb single rod - 2nd station 7.0 25 3-Fc direct engraving 11.0 23 3-Fd rod - 10mm 8.0 15

[00160] As can be seen in Table 5, the MVTR is very high for Packaging Material 3-A, which does not contain styrene copolymer or wax in the coating. Even with two coating layers, the MVTR of Material 3-AA is only slightly reduced in the absence of a styrene copolymer or wax. MVTR is also Petition 870260039395, dated April 28, 2026, pp. 52-68 47 / 49 too high for Packaging Material 3-B, which does not contain wax in the coating.

[00161] As demonstrated in Table 4, the 3-D and 3-Fa to 3-Fd Packaging Materials, which contain wax and a styrene copolymer according to the invention in the coating, exhibit a very low MVTR. Example 3 therefore confirms that satisfactory moisture barrier properties of the recyclable packaging materials according to the present invention can be obtained not only in laboratory tests but also through machine tests. Example 4

[00162] All materials in Example 4 were obtained through machine testing, according to the methods indicated in Table 6.

[00163] Coating composition F was used for applying a coating to the first side of Paper Substrates 4 and 5, with the coating basis weight shown in Table 6 below, for the manufacture of Packaging Materials 4-F and 5-F.

[00164] The MVTR value of Packaging Materials 4-F and 5-F was determined as described above and the results are shown in Table 6 in comparison with those of the 3-Fb and 3-Fd machine tests. Table 6: Comparison of different paper substrates coated with F Packaging Material Paper Substrate Coating Method Coating Grammage [g / m2] MVTR [g / m2 / 24h] 4-F 4 direct engraving 9.0 61 5-F 5 single rod 2nd station 10.0 12 3-Fb 3 single rod 2nd station 7.0 25 3-Fd 3 rod - 10mm 8.0 15

[00165] As can be seen in Table 6, all packaging materials according to the present invention provide Petition 870260039395, dated 04 / 28 / 2026, pp. 53 / 68 48 / 49 satisfactory moisture barrier properties, in addition to being recyclable. As discussed above, Paper Substrate 4 has a lower Hagerty porosity. Therefore, the MVTR of Packaging Material 4-F is higher than that of the other samples.

[00166] In short, the Hagerty porosity of the paper substrate becomes more important when the process is scaled up. In other words, the present inventors noted that, to obtain consistent moisture barrier properties on an industrial scale, the paper should preferably have a Hagerty porosity greater than 6,500 s / 100 cm3. Without wanting to get bogged down in theory, this can be attributed mainly to the hydrodynamics of the coating solution on an industrial scale, which operates continuously. While it is easy to obtain a coating on the entire surface of the paper substrate under static laboratory conditions, on an industrial scale the coating solution is applied to a constantly moving paper substrate, and achieving the same coating quality is a challenge. The use of a paper substrate with a Hagerty porosity greater than 6.500 s / 100 cm3, according to a preferred embodiment of the invention, allows the coating to be applied uniformly over the entire surface of the paper substrate, even on an industrial scale, thus providing consistently high moisture barrier properties. Example 5

[00167] Table 7 presents a comparison of the 1-D, 2-D, and 3-D Packaging Materials described above. Table 7: Comparison of different D-coated paper substrates Packaging material Paper substrate Coating method Coating weight [g / m2] MVTR [g / m2 / 24h] 1-D 1 manual applicator 6.0 25 2-D 2 manual applicators 5.7 56 3-D 3 manual applicators 6.3 28 Petition 870260039395, dated April 28, 2026, pp. 54-68 49 / 49

[00168] As shown in Table 7, Packaging Materials 1-D and 3-D, composed of base papers with Hagerty porosity greater than 10,000 s, exhibit lower MVTRs, i.e., even better moisture barrier properties, compared to Material 2-D.

Claims

1. Food packaging material, characterized in that it comprises: a paper substrate having a first side and a second side, the second side being opposite to the first side, wherein the paper substrate is coated at least on the first or second side with a coating comprising wax and a copolymer selected from styrene-butadiene copolymer and / or styrene-acrylic copolymer, wherein the paper substrate is a base sheet of cellulose fibers, wherein the cellulosic fibers are refined to 30 °SR or more, measured in accordance with ISO 5267, and wherein the coating, comprising the wax and the copolymer, is present in an amount of at least 1% by weight, based on the paper substrate and the coating.

2. Food packaging material, according to claim 1, characterized in that it has a moisture vapor transmission rate, MVTR, of less than 75 g / m2 / 24h, preferably less than 50 g / m2 / 24h, more preferably less than 25 g / m2 / 24h, determined at 85% RH and 23 °C.

3. Food packaging material, according to any of the preceding claims, characterized in that the paper substrate has a Hagerty porosity greater than 6,500 s / 100 cm3, preferably greater than 10,000 s / 100 cm3, more preferably greater than 20,000 s / 100 cm3, even more preferably greater than 30,000 s / 100 cm3, and much more preferably greater than 50,000 s / 100 cm3.

4. Food packaging material, according to any of the preceding claims, characterized in that the paper substrate has a basis weight of 30 to 200 g / m2, in a preferred mode of 30 to 150 g / m2, or in a more preferred mode of 40 to 150 g / m2.

5. Food packaging material, according to any of the preceding claims, characterized in that the coating comprising wax and copolymer is present in an amount of no more than 25% by weight, preferably no more than 20% by weight, or more preferably no more than 15% by weight, based on the paper substrate and the coating.

6. Food packaging material, according to any of the preceding claims, characterized in that the paper substrate is calendered and / or overcalendered.

7. Food packaging material, according to any of the preceding claims, characterized in that the paper substrate before coating has a Sheffield surface smoothness / roughness of less than 600 Sheffield Units (SU), preferably less than 400 SU, more preferably less than 350 SU, and even more preferably less than 300 SU, determined in accordance with Tappi T538 standard.

8. Food packaging material, according to any of the preceding claims, characterized in that the paper substrate is made of natural cellulosic fibers, preferably comprising at least 50% by weight of cellulosic fibers, preferably at least 60% by weight of cellulosic fibers, more preferably at least 85% by weight of cellulosic fibers, and even more preferably at least 90% by weight of cellulosic fibers.

9. Food packaging material according to claim 8, characterized in that said cellulosic fibers are refined to 55 °SR (Schopper Riegler) or more, preferably to 60 °SR or more, more preferably to 65 °SR or more.

10. Food packaging material, according to any of the preceding claims, characterized in that it has a fluorine content of less than 100 ppm, preferably less than 90 ppm, and most preferably less than 80 ppm.

11. Food packaging material, according to any of the preceding claims, characterized in that it is recyclable by repulping and recoverable according to EN 13430 by at least 85% by weight, preferably by at least 90% by weight, and more preferably by at least 95% by weight.

12. Food packaging material, according to any of the preceding claims, characterized in that it has a Cobb concentration in 30 minutes measured according to TAPPI 441 of less than 10 g / m2, preferably less than 8 g / m2, and more preferably less than 5 g / m2.

13. Food packaging material, according to any of the preceding claims, characterized in that the paper substrate is pre-coated at least on the first or second side with a grease barrier precursor selected from polysaccharides such as starch, a starch derivative, carboxymethylcellulose, carboxyethylcellulose, chitosan, alginate, dextrin, ethylene-vinyl alcohol copolymer, polyvinyl alcohol and a mixture thereof; and the coating, comprising wax and copolymer, is applied at least to the first or second side impregnated with the grease barrier precursor.

14. Food packaging material according to claim 13, characterized in that the grease barrier precursor is present in an amount of less than 14% by weight, preferably less than 10% by weight, more preferably less than 5% by weight and even more preferably less than 3% by weight relative to the paper substrate.

15. Food packaging material, according to any of the preceding claims, characterized in that it forms a food package.

16. A method for manufacturing a food packaging material, as defined in claim 1, characterized in that the coating is applied to the paper substrate by direct rotogravure or using a single bar or by curtain coating or by spray coating or by gluing press coating or by air blade coating or by flexographic coating.

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