Barrier paper composition

Abstract

The present invention relates to an oil and grease and oxygen barrier composition comprising MFC and stearyl stearate, and optionally AKD. The oil and grease and oxygen barrier composition may be incorporated into the cellulose pulp or applied into a surface of a cellulose paper substrate. Also, an oil and grease and oxygen bi-layer barrier is disclosed, both providing a paper article is one of a recyclable oil and grease and oxygen resistant paper, a renewable oil and grease and oxygen resistant paper or a home compostable oil and grease and oxygen resistant product, preferably for consumer food products suitable for use in consumer food products.

Description

[0001] BARRIER PAPER COMPOSITION

[0002] FIELD OF THE INVENTION

[0003]

[0001] The present invention relates to an oil and grease and oxygen barrier composition comprising a microfibrillated cellulose (MFC) and stearyl stearate (SS), and optionally alkyl ketene dimer (AKD). The oil and grease and oxygen barrier composition may be incorporated into the cellulose pulp or applied into a surface of a cellulose paper substrate. Also, an oil and grease and oxygen bi-layer barrier is disclosed. Both the barrier composition and the bi-layer barrier provide paper article that is one of a recyclable oil and grease and oxygen resistant paper, a renewable oil and grease and oxygen resistant paper or a home compostable oil and grease and oxygen resistant product, preferably for consumer food products. The invention also refers to processes for producing cellulosic substrate.

[0004] BACKGROUND

[0005]

[0002] Cellulose-based articles are used in a wide range of products, and may include general categories such as paper, cardboards, food containers, and many others. Many of these products also include folds or bends, such as compartments in a paper plate or food container.

[0006]

[0003] Worldwide restrictions in using plastic materials in disposable goods, especially in Europe, for instance, increasingly lead to the research and development of related sustainable and renewable-based barrier materials, in order to achieve excellent barrier properties in recyclable oil and grease and / or oxygen resistant papers, for example, or a home compostable oil and grease and / or oxygen resistant products, preferably for consumer food products.

[0007]

[0004] Regarding oil and grease barriers coatings, they are required to prevent the egress from the package of oil and grease of the packaged product as well as to prevent the ingress into the package of oil and grease, if preferred, that might deteriorate the quality of the packaged product.

[0005] As one example of the need for oil and grease resistance, there are many packages, such as pizza boxes and hamburger wrappers, which must be treated to prevent the unsightly staining of the package by the oil and grease from the food or other items that are packaged. Current treatments used for oil and grease resistance include treatment with fluorocarbons or extrusion coating the paper with a layer of polymer, such as LDPE. However, these treatments are not desirable in view of the worldwide trend towards reduction of the use of plastic materials. Moreover, fluorocarbon treatment often causes issues with consumer perception; while LDPE coating often requires a high coating thickness, increasing costs.

[0008]

[0006] Oil and grease barrier coatings are used in paper and paperboard packaging to provide oil and grease barrier properties to paper and paperboard by reducing or eliminating the permeability of oil and grease through the material and / or the absorption of oil and grease in the fiber structure.

[0009]

[0007] Besides oil and grease barrier coatings, another important barrier for preventing food from degradation is the oxygen barrier. Paper packaging requires an oxygen barrier to protect packaged products from oxidative degradation, preserving their quality, freshness, and shelf life. Paper itself has high oxygen permeability, making it unsuitable for sensitive products without the application of barrier layers.

[0010]

[0008] Many foods and chemical products are sensitive to oxidation, which can lead to deterioration, rancidity, loss of flavor or unpleasant flavors, color changes, and the formation of undesirable compounds. This is critical for products like coffee, snacks, nuts, and fat-rich foods. In addition, an oxygen barrier reduces the proliferation of aerobic microorganisms and the degradation of oxygen-sensitive compounds, allowing for longer preservation without excessive use of preservatives, extending the shelf-life of the products.

[0011]

[0009] Thus, developing effective oil and grease and oxygen barriers is essential for paper packaging to be used in more demanding applications without compromising product protection. There is a need for an enhanced oil and grease and oxygen barrier composition that provides good barrier properties to papers and cardboards while using even in low amounts providing for sustainable and renewable-based barrier materials.

[0012] SUMMARY OF THE INVENTION

[0013]

[0010] A first objective of the present invention is to provide an oil and grease and oxygen barrier composition comprising MFC and stearyl stearate, and optionally AKD. The oil and grease and oxygen barrier composition of the present invention may be incorporated into a cellulose pulp or applied to a cellulosic substrate.

[0014]

[0011] Another objective of the present invention is to provide an oil and grease and oxygen bi-layer barrier with an internal layer comprising MFC and optionally AKD and an external layer comprising stearyl stearate.

[0015]

[0012] Both embodiments of the present invention provide paper article that is one of a recyclable oil and grease and oxygen resistant paper, a renewable oil and grease and oxygen resistant paper or a product that is an oil and grease and oxygen resistant home compostable product; preferably for consumer food products suitable for use in consumer food products.

[0016]

[0013] Another objective of the present invention is to provide processes for producing cellulosic substrates.

[0017] DRAWINGS

[0018]

[0014] Fig. 1 is a generic paper production flowchart, indicating the preferred application points (i, ii and iii) of the oil and grease and oxygen barrier composition of the present invention.

[0019]

[0015] Fig. 2 is a generic representation of a multi-layer head-box, indicating the possible application points (iv) of the oil and grease and oxygen barrier composition of the present invention.

[0016] Fig. 3 is a generic representation of paper machine with two forming tables, indicating the possible application points (v) of the barrier formulation of the present invention.

[0020] DETAILED DESCRIPTION OF THE INVENTION

[0021]

[0017] In one aspect, the present invention is an oil and grease and oxygen barrier composition having MFC and stearyl stearate.

[0022]

[0018] MFC (CAS 65996-61 -4) is microf i brillated cellulose or, alternatively, cellulose microfibril (CMF), a type of cellulose nanofiber containing multiple elementary fibrils with both crystalline and amorphous regions, having a high aspect ratio with width of 10-100 nm and length 0.5-10 pm. MFC are usually produced by mechanical treatment of highly purified wood pulp or non-wood plant pulp, often preceded by pretreatment methods and usually contain residual hemicelluloses. Reference is made to the Proposed New TAPPI Standard: Standard Terms and Their Definition for Cellulose Nanomaterial (Wl 3021 ).

[0023]

[0019] The MFC fiber material that is used as starting material may be based on any plant material that contains cellulose and was subjected to a microfibillation. The originating plant material may be wood. The wood can be from softwood trees such as spruce, pine, fir, larch, douglas-fir or hemlock, or from hardwood trees such as birch, aspen, poplar, alder, eucalyptus or acacia, or from a mixture of softwood and hardwood. Also, recycled fibers may be used as starting materials.

[0024]

[0020] In one aspect of the present invention, the MFC is from a pulp such as mechanical pulp, thermomechanical pulp, chemi-thermomechanical pulp and chemical pulp. For example, Bleached Eucalyptus Kraft Pulp (BEKP), Northern Bleached Softwood Kraft pulp (NSBK), Bleached Softwood Kraft pulp, Bleached Hardwood pulp, unbleached softwood and hardwood Kraft pulps, Sulfite Bleached pulp, Bleached Chemi-Thermo Mechanical Pulp ("BCTMP"), are used to obtain MFC. Each type of pulp provides slightly different MFC’s, having different properties and dimensions. Preferably, the MFC is from hardwood pulp, more preferably from Bleached Eucalyptus Kraft Pulp (BEKP).

[0021] As the diameter of cellulose fibrils depends on the source of the wood and the method of fibrillation employed, MFC’s from different wood sources and previous treatment process such as pulping may provide MFC’s with different characteristics. Examples of fibrillation are single or multiple pass refining, with high shear disintegration or liberation of fibrils, carried out with a refiner, grinder, homogenizer, colloider, friction grinder, ultrasound sonicator, single- or twin-screw extruder, fluidizer such as microfluidizer, microfluidizer or another fluidizer-type homogenizer. Depending on the method, the product might also contain fines, or nanocrystalline cellulose or e.g., other chemicals present in wood fibers or in papermaking process. Preferably, mechanical fibrillation is used to obtain the MFC used in the present invention. Alternative refining may be employed wherein any type of refiner is used, i.e., fibrillation with low, medium or high shear with a rotating disc and a stator to obtain the MFC used in the present invention. Notwithstanding the slight variation of characteristics of MFCs obtained from different sources or through different methods, all materials classified as MFC are suitable for use in the present invention. The oil and grease and oxygen composition and the formed oil and grease and oxygen barrier of the present invention comprise MFC.

[0025]

[0022] The oil and grease and oxygen barrier composition of the present invention also has stearyl stearate. Stearyl stearate (SS) is a fatty acid ester which is used as raw material of emulsifiers or oiling agents for foods, spin finishes and textiles; lubricants for plastics; paint and ink additives; surfactants and base materials for cosmetics, for instance.

[0026]

[0023] Specifically in the cosmetic industry, SS is used as an emollient and moisturizing agent due to its high permeability in the superficial layers of the skin. However, the use of SS as well as the combination of SS and MFC are not known for paper applications, since this kind of paper substrate presents different properties compared to skin.

[0027]

[0024] Thus, in a non-obvious way, the application of SS in paper barriers as an additional surface layer was explored in the present invention in order to obtain a thin coating film with additional properties for paper applications. Unexpectedly, results revealed that the synergy and interaction of SS and MFC promoted very good barrier properties on paper products, as it can be seen in Examples 1 and 2. When combined with SS, the barrier properties were achieved with lower amounts of MFC. In other words, using SS with a MFC allows to use less MFC to achieve similar KIT numbers of MFC alone.

[0028]

[0025] The oil and grease and oxygen barrier composition of the present invention comprises at least MFC at 95-99,5 %wt. of the dry total weight of the oil and grease and oxygen barrier composition and stearyl stearate at 0,5-5 % wt. of the dry total weight of the oil and grease and oxygen barrier dry composition. Preferably, the oil and grease and oxygen barrier composition of the present invention comprises MFC between 97-99 % wt. of the dry total weight of the oil and grease and oxygen barrier composition and stearyl stearate between 1 -3 % wt. of the dry total weight of the oil and grease and oxygen barrier composition.

[0029]

[0026] The oil and grease and oxygen composition of the present invention may also include alkyl ketene dimer AKD. AKD is a group of organic compounds based on the 4-membered ring system of oxetan-2-one, with C14-C16 alkyl chains in position 3 and C15-C17 alkylidene chains in position 4. The AKD may be included in the composition of the present invention with the MFC and the stearyl stearate. Any type of AKD may be used. For example, the AKD may be one selected from: solid alkyl ketene dimer AKD, liquid alkyl ketene dimer (L-AKD), or mixtures thereof. Incorporation of AKD may be from alkyl ketene dimer (AKD), liquid-AKD (L-AKD) or any other type of AKD up to 10 % wt. of the dry total weight of the oil and grease and oxygen barrier composition. The AKD or any other type of AKD may be between 0.1 and 10 % wt. of the dry total weight of the oil and grease and oxygen barrier composition.

[0030]

[0027] Two or more types of AKD may be used as mixtures of AKD's in the oil and grease and oxygen barrier composition of the present invention. A mixture of AKD and L-AKD may be incorporated as a mixture of AKD up to 10 % wt. of the dry total weight of the oil and grease and oxygen barrier composition. For instance, if a mixture of AKD’s, the L-AKD may be between 10-90 % wt. of the mixture and the AKD may be between 10-90 % wt. of the AKD’s mixture.

[0028] The oil and grease and oxygen barrier composition of the present invention may be incorporated into a cellulose pulp or applied to at least one surface of a cellulosic substrate, forming a cellulosic substrate with oil and grease and oxygen barrier properties. A cellulose substrate may be a cellulose pulp “as is”, a cellulose derivative, a paper, a cardboard, a containerboard, a flexible paper, a molded pulp packaging, a film and others, as well as disposable products produced from these materials.

[0031]

[0029] When applied to at least one surface of a cellulose substrate, the oil and grease and oxygen barrier composition of the present invention may be applied to the cellulosic substrate between 2-20 gsm (gram per square meter).

[0032]

[0030] Alternatively, the oil and grease and oxygen barrier composition of the present invention may be incorporated into a cellulose pulp or a cellulosic substrate, forming a cellulosic substrate with oil and grease and oxygen barrier properties. The oil and grease and oxygen barrier composition may be incorporated into a pulp or a cellulose substrate during any point of fabrication of the cellulose substrate, as depicted at Fig. 1 , or any other suitable point. Preferably, the oil and grease and oxygen barrier composition may be incorporated into the cellulose substrate forming at least 6 kg of the dry oil and grease and oxygen barrier composition per ton of dry cellulose substrate. Preferably, between of 6-72 kg of dry oil and grease and oxygen barrier composition per ton of dry cellulose substrate.

[0033]

[0031] The present invention also provides a method of obtaining a cellulosic substrate having an oil and grease and oxygen barrier composition, forming a cellulosic substrate with oil and grease properties when the oil and grease and oxygen barrier composition is applied to at least one or more of a surface of a wet pulpand a surface of a pre-dried cellulosic substrate.

[0034]

[0032] Fig. 1 is an example of a generic paper production flowchart with the steps of production of paper. Paper production comprises a pulp or stock preparation, or pulp furnish, with a pulp disintegration in a pulper to provide homogenous pulp free of clumps or with different densities. The pulp or stock is screened and may be refined with, for instance, a rotating disc. After refining wet-end additives are incorporated and mixed with the pulp. The pulp is then directed to a head-box that dispenses the pulp mass or stock into a forming table with an endless moving wire, where a first dewatering of the pulp occurs. The partially dewatered pulp is then submitted to a Dandy Roll for removing unevenness from the pulp, providing a wet pulp cellulosic substrate, or a pre-dried cellulosic substrate. Presses in the press section further dewater the paper for a drying step. The drying step begins at the pre-dryers where further water is removed and the paper is then formed, although with a high amount of water. A size press may be present providing a first covering for the paper if desired. The post dryers remove the added water or solvent applied at the size press and the formed sheet of paper is further dried at the post dryers and then, if desired, calendared, when the sheet of paper is fully formed and may be rolled up forming jumbo reels.

[0035]

[0033] Accordingly, in one embodiment, the oil and grease and oxygen barrier composition of the present invention may be applied to the pulp furnish during the pulp stock preparation. In this embodiment, the oil and grease and oxygen barrier composition of the present invention is mixed directly into the pulp furnish that will be converted into a sheet of cellulosic substrate, for instance, a paper, preferably into the mixture of cellulosic fibers that make up the mass or raw material used to produce the cellulosic substrate. In such embodiment, the oil and grease and oxygen barrier composition of the present invention is considered an additive for cellulose pulp; and the additive is applied to a pulp furnish. Accordingly, the pulp furnish is then converted into a sheet of cellulosic substrate, for instance, a paper, of the present invention.

[0036]

[0034] The oil and grease and oxygen barrier composition of the present invention may also be applied to different steps during the cellulosic substrate formation, such as into the surface of a wet pulp and to the surface of the pre-dried cellulosic substrate.

[0037]

[0035] Alternatively, the oil and grease and oxygen barrier composition of the present invention may be applied to the surface of the wet pulp cellulosic substrate. In another embodiment, the oil and grease and oxygen barrier composition of the present invention may be applied to the surface of a pre-dried cellulosic substrate. Accordingly, the oil and grease and oxygen barrier composition may be applied into two or more of the mentioned formation steps.

[0038]

[0036] In one embodiment of the present invention, the oil and grease and oxygen barrier composition of the present invention may be applied to the top of the fiber furnish along the forming wire of the cellulosic substrate, and this deposition may occur in different positions of the forming wire. Accordingly, the fiber furnish will be converted into a sheet of cellulosic substrate, for instance, a paper.

[0039]

[0037] In another embodiment of the present invention, the oil and grease and oxygen barrier composition of the present invention may be applied as a single layer on at least one side of a cellulosic substrate between the pre- and post-drying sections. Accordingly, the pre- or post-dried cellulosic substrate is then converted into a sheet of cellulosic substrate of the present invention.

[0040]

[0038] Fig. 2 is a generic representation of a multi-layer head-box equipment, indicating the possible application points (iv) of the oil and grease and oxygen barrier composition of the present invention. In one embodiment, the oil and grease and oxygen barrier composition of the present invention may be used in paper machines with a multi-layer headbox, and the oil and grease and oxygen barrier composition may be applied as one of the outer I surface layers or between the two paper layers, such as between at least one of the surface layer and the center layer. Fig. 3 is a generic representation of paper machine with two forming tables, indicating the possible application points (v) of the barrier formulation developed in this innovation. In one embodiment, the oil and grease and oxygen barrier composition of the present invention may be used in paper machines with two forming tables, and the oil and grease and oxygen barrier composition may be applied as a layer on the on top of the fiber furnish along the forming wire or in the upper table, or in the under table, or in both.

[0041]

[0039] In one aspect of the present invention, it is provided a paper article with oil and grease and oxygen barrier features. The paper article of the present invention may be a paper article comprising a cellulosic substrate and a oil and grease and oxygen barrier composition. If the oil and grease and oxygen barrier composition is added to the pulp furnish prior the formation of the paper article, the oil and grease and oxygen barrier composition of the present invention is mixed directly into the pulp furnish that will be converted into a sheet of paper, preferably applied in the mixture of cellulosic fibers that make up the mass or raw material used to produce, for instance, the paper article.

[0042]

[0040] In another aspect, the present invention also provides a paper article, which may be a paper article comprising a paper substrate and a single layer of the oil and grease and oxygen barrier composition of the present invention, having MFC and stearyl stearate. The oil and grease and oxygen barrier composition may be applied to the surface of the paper substrate, forming a paper article with oil and grease properties. The oil and grease and oxygen barrier composition may be also applied on both surfaces of the paper substrate, after the formation of the paper, having oil and grease resistance on both sides of the paper article.

[0043]

[0041] It is also disclosed a process for producing an oil and grease and oxygen barrier cellulosic article of the present invention, wherein the wet pulp or the predried cellulosic article is converted into a sheet of cellulosic article having an oil and grease and oxygen barrier. For instance, when the wet pulp having the oil and grease and oxygen barrier composition; or the pre-dried cellulosic substrate having the oil and grease and oxygen barrier composition is converted into a sheet of paper, the sheet of paper is a paper article having an oil and grease bi-layer barrier.

[0044]

[0042] The process for producing the cellulosic substrate having an oil and grease and oxygen barrier composition comprises applying the oil and grease and oxygen barrier composition of the present invention into a surface of a wet pulp or into a surface of a pre-dried cellulosic substrate, or into both, by a dosing system such as Film press, size press, Spray bar, coating system or any other suitable dosing system.

[0045]

[0043] Also, there is provided a process for producing a cellulosic article having an oil and grease and oxygen barrier composition, wherein the oil and grease and oxygen barrier composition is incorporated into the furnish during the pulp stock / pulp furnish preparation, wherein the furnish is converted into a sheet of paper.

[0046]

[0044] In any event, there is provided a paper article having oil and grease and oxygen barrier comprising a cellulosic substrate and having at least one surface, wherein the at least one surface is covered with a layer of the oil and grease and oxygen barrier composition of the present invention.

[0047]

[0045] The oil and grease and oxygen barrier composition of the present invention may comprise a poly aluminum chloride (PAC). When PAC is present in the oil and grease and oxygen barrier composition of the present invention, the amount of PAC is 3 % or less, in dry weight of the oil and grease and oxygen barrier composition.

[0048]

[0046] The oil and grease and oxygen barrier composition of the present invention may also comprise a dye. Preferably, the dye is present at 2 % wt. or less of dry of the weight of the oil and grease and oxygen barrier composition. When the dye is present, the oil and grease and grease component may comprise a 1 % wt. or less of the dry weight of a dye fixing agent.

[0049]

[0047] In another aspect, the present invention also provides an oil and grease and oxygen bi-layer barrier having at least two layers, one internal layer, in contact with a surface of a cellulosic substrate, and an external layer deposited over the internal layer. Accordingly, the internal layer may comprise MFC, and optionally AKD; and the external layer may comprise stearyl stearate. Both the internal and external layers form an oil and grease and oxygen bi-layer barrier, preferably for a cellulosic substrate.

[0050]

[0048] The internal layer of the oil and grease and oxygen bi-layer barrier comprises MFC at least at 85% wt. of the dry total weight internal layer of the oil and grease and oxygen bi-layer barrier; and the external layer of the oil and grease and oxygen bi-layer barrier comprise stearyl stearate at least at 90% wt. of the dry total weight of the external layer of the oil and grease and oxygen bi-layer barrier.

[0051]

[0049] Preferably, the internal layer of the oil and grease and oxygen bi-layer barrier may comprise MFC at 90-100 % wt. of the dry total weight of the internal layer.

[0050] Accordingly, the external layer of the oil and grease and oxygen bi-layer barrier may comprise stearyl stearate at 95-100 % wt. of the dry total weight of the external layer.

[0052]

[0051] In one aspect of the present invention, the internal layer and external layer of the oil and grease and oxygen bi-layer barrier form the oil and grease and oxygen bi-layer barrier. Preferably, the grammage of the oil and grease and oxygen bi-layer barrier is 2-24 gsm, preferably having an internal layer having 2-20 gsm and an external layer up to 4 gsm.

[0053]

[0052] The internal layer of the oil and grease and oxygen bi-layer barrier of the present invention may further comprise AKD. When present, the AKD may be at least 0,1 % wt. of the dry total weight of the internal layer of the oil and grease and oxygen bi-layer barrier.

[0054]

[0053] Accordingly, AKD may be one selected from: solid alkyl ketene dimer AKD, liquid AKD (L-AKD), or mixtures thereof.

[0055]

[0054] A single AKD may be used. For instance, if AKD is used, the alkyl ketene dimer (AKD) may be present up to 10 % wt. of the dry total weight of the internal layer of the oil and grease and oxygen bi-layer barrier. If liquid AKD is used, the liquid AKD may be present up to 10 % wt. of the dry total weight of the internal layer of the oil and grease and oxygen bi-layer barrier. The AKD or any other type of AKD me be between 0.1 to 10 % wt. of the dry total weight of the internal layer of the oil and grease and oxygen bi-layer barrier.

[0056]

[0055] Mixtures of AKD are also desired for incorporation into the internal layer. For instance, a mixture of solid AKD and liquid AKD may be incorporated into the internal layer.

[0057]

[0056] The present invention also provides a process for producing a cellulosic substrate having an oil and grease and oxygen bi-layer barrier, wherein the internal layer of the oil and grease and oxygen bi-layer barrier may be applied to a surface of a wet pulp and the external layer of the oil and grease and oxygen bi-layer barrier may be applied over the internal barrier.

[0057] Also, in another aspect of the present invention, the internal layer of the oil and grease and oxygen bi-layer barrier may be applied to a surface of a wet pulp by size press or by a dosing system such as Film press, Spray bar, coating system or any other suitable dosing system and the external layer of the oil and grease and oxygen bi-layer barrier may be applied over the internal barrier by size press or by a dosing system such as Film press, Spray bar, coating system or any other suitable dosing system.

[0058]

[0058] In a further aspect, the internal layer of the oil and grease and oxygen bi-layer barrier may be applied to a surface of a pre-dried cellulosic substrate and the external layer of the oil and grease and oxygen bi-layer barrier may be applied over the internal barrier.

[0059]

[0059] In a further aspect, the internal layer of the oil and grease and oxygen bi-layer barrier may be applied to a surface of a pre-dried cellulosic substrate by size press or by a dosing system such as Film press, Spray bar, coating system or any other suitable dosing system and the external layer may be applied over the internal barrier by size press or by a dosing system such as Film press, Spray bar, coating system or any other suitable dosing system.

[0060]

[0060] In any aspect of the present invention the cellulosic substrate may be a paper, thereby forming a paper article having an oil and grease and oxygen bi-layer barrier. The paper article preferably has a cellulosic substrate with at least one surface, the at least one surface is preferably covered with a layer of an oil and grease and oxygen bi-layer barrier of the present invention, forming a paper article comprising a grease barrier providing a Kit of at least 7, preferably 9-12, as determined using TAPPI T 559 standard.

[0061]

[0061] A paper article comprising the oil and grease and oxygen bi-layer barrier of the present invention on at least one surface of the paper article, or the oil and grease and oxygen bi-layer barrier composition of the present invention incorporated into the paper article, there is provided an oil and grease resistant recyclable paper, an oil and grease resistant renewable paper or an oil and grease resistant home compostable product; preferably for consumer food products. In any event, and according to Table 1 , the paper article has an improved oil and grease and oxygen bi-layer barrier, preferably for consumer food products.

[0062]

[0062] Also, the cellulosic substrate of the present invention may have an oil and grease and oxygen barrier composition incorporated into the pulp furnish or applied to the cellulosic substrate as an external layer, which receives on top an oil and grease and oxygen bi-layer barrier, forming thereupon another barrier. In this case, the internal layer, comprising MFC, of the oil and grease and oxygen bi-layer barrier, would not be directly applied to the cellulosic substrate surface. In this case, the internal layer of the oil and grease and oxygen bi-layer barrier would be applied on top of the oil and grease and oxygen barrier composition, for instance, which then would receive the external layer of the oil and grease and oxygen bi-layer barrier.

[0063] EXAMPLES

[0064]

[0063] The examples presented herein are non-exhaustive, they have the purpose of illustrating the invention and should not be used as a basis to limit it.

[0065] Example 1

[0066]

[0064] In order to evaluate the oil and grease property of the oil and grease barrier composition of the present invention, a pulp furnish formulation was provided, having 79% hardwood fiber pulp, 18% softwood fiber pulp and 3% of AKD. The oil and grease barrier comprised varying amounts of MFC at 4 wt% of the oil and grease barrier, AKD, liquid AKD and Stearyl Stearate, as indicated at each experiment at Table 1 . Varying grammages of 0 g / m2; 5 g / m2; 10 g / m2 and 15 g / m2 of the oil and grease barriers of the present invention were applied to the surface of the papers and the KIT numbers were measured.

[0067]

[0065] It is important to emphasize that the cellulosic substrates are herein provided as examples and shall not restrict the application of the present invention to different furnish compositions.

[0068]

[0066] The oil and grease barrier of the present invention was applied at the following points during the paper formation: stock preparation; forming section and size press.

[0067] The products obtained were analyzed according to the T 559 cm-12 standard

[0069] - “Grease resistance test for paper and paperboard” (TAPP I, 2012), which allows measuring the resistance degree of the paper sheet to the absorption of oils, fats and greases. The results of this analysis are expressed as NsKIT, and the higher the value of this measure, the higher the barrier performance. The results are shown at Table 1 .

[0070] Table 1 . Experimental design applied to prove the performance of the developed formulations in providing barrier properties.

[0068] Reference is made to Table 1 demonstrating the use of MFC (at 4% solids) and stearyl stearate for an oil and grease composition results in good KIT numbers for a given cellulosic substrate.

[0071]

[0069] The Kit test is a method for testing the degree of repellency and / or the antiwicking characteristics of paper or paperboard treated with an oil and grease resistant barrier. The test is run according to TAPPI Test Method T559. The test involves placing a series of numbered reagents (varying in surface tension and viscosity or “aggressiveness”) onto the surface of the sample. The solutions are numbered from 1 (the least aggressive) to 12 (the most aggressive). The highest numbered solution that does not stain the surface is reported as the “kit rating” the the ”KIT number”.

[0072]

[0070] Experiments 1.1 ; 1.2; 1.3 and 1.4 at Table 1 demonstrate good KIT increments for the bi-layer of the present invention, when the oil and grease bi-layer barrier is provided with an internal layer comprising MFC and an external layer comprising stearyl stearate. For instance, an increment (A) of at least 1 KIT point may be achieved using the external layer combined with the internal layer, when compared to the use of the internal layer alone comprising MFC.

[0073]

[0071] From the testes, experiments 2.1 .1 ; 2.1.2; 2.1.3; 2.2.1 ; 2.2.2 and 2.2.3, in the “Forming section” alone (i.e. without the application of Size Press), demonstrate that the combined use of MFC and stearyl stearate provides similar KIT numbers, even when compared with the use of MFC alone (Experiments 1.1 ; 1.2; 1.3 and 1.4 at Table 1 , “Forming section”) although having lower amounts of MFC in the composition. In other words, using ester stearyl stearate with a MFC allows to use less MFC to achieve similar KIT numbers of MFC alone for oil and grease resistance. When compared to the Size Press application, the present invention also provides good KIT numbers, for instance, the invention examples 1.2-1 .4, having only the Size Press application over the MFC barr.

[0074]

[0072] When any AKD is used, the oil and grease barrier of the present invention provides good oil and grease properties. According to the Table 1 , experiments 3.1.1 ; 3.1.2; 3.1.3; 3.2.1 ; 3.2.2; 3.2.3; 4.1.1 ; 4.1.2; 4.1.3; 4.2.1 ; 4.2.2 and 4.2.3 demonstrate good KIT numbers that provide good oil and grease barrier to a cellulosic substrate.

[0075]

[0073] The results described at Table 1 allow to conclude that:

[0076]

[0074] Combining MFC with the oil and grease barrier component results in KIT values greater than or equal to 7 when the grammages of the oil barrier composition applied to the surface of the cellulosic paper are higher than or equal to 10 g / m2.

[0077]

[0075] Also, grammages of the oil and grease barrier composition applied to the surface of the cellulosic paper higher than or equal to 10 g / m2 equally preferred.

[0078]

[0076] The oil and grease barrier composition and paper article of the present invention result in renewable, biodegradable and recyclable materials and, furthermore, the oil and grease barrier composition are adequate for contacting food, according to FDA 21 CFR 176.170 and FDA 21 CFR 176.180; BfR XXXVI, XXXVI / I, XXXVI / I I and XXXVI / 111 ; REACH SVHC; Appendix XIX and Appendix XVII.

[0079] Example 2

[0080]

[0077] In order to evaluate the oxygen barrier property of the present invention, tests were performed by measuring the oxygen transmission rate. The Oxygen Transmission Rate (OTR) of the products were analyzed using a MOCON® OX- TRAN® 2 / 20 equipment (MOCON®) at a standard temperature (23°C) and two different relative humidity (0% and 50% RH). This methodology allows measuring the steady state rate at which the oxygen gas permeates through a film at specified conditions. The results of this analysis are expressed in cc / m2 / 24 hr units (SI), and the lower the value of this measure, the higher the oxygen barrier performance, it means, the better is the formulation for oxygen barrier. On the opposite way, the higher the value of Oxygen Transmission Rate means a higher permeability, or a lower oxygen barrier performance. The results are shown in Tables 2, 3, 4 and 5.

[0081] Table 2. Results of oxygen barrier (Oxygen Transmission Rate) at 0% of relative humidity using a highly fibrillated MFC.

[0082] (*’No = Not possible to measure OTR due oxygen permeability above the limit of quantification of the equipment.

[0083] Table 3. Results of oxygen barrier (Oxygen Transmission Rate) at 50% of relative humidity using a highly fibrillated MFC.

[0084] (*’No = Not possible to measure OTR due oxygen permeability above the limit of quantification of the equipment.

[0085]

[0078] As can be observed from the results in Tables 2 and 3, for the handsheets formed without the additional layer of stearyl stearate applied in the Size Press, the oxygen permeability was high or even above the equipment's quantification limit (thus, not measurable). However, with the application of stearyl stearate at the Size Press, the formed handsheets exhibited high oxygen barrier values (or low permeability), reaching competitive values for food contact.

[0086]

[0079] It can also be observed that, with the addition of AKD in the formulation (and the consequent reduction in the relative content of MFC), there is a tendency for increased oxygen permeability. However, the subsequent addition of stearyl stearate in the top layer allows the oxygen barrier to be restored.

[0080] The developed formulation does not provide a water vapor barrier. However, it allows achieving high oxygen barrier values even at 50% relative humidity.

[0087]

[0081] Using a medium fibrillated MFC, the oxygen barrier potential becomes less significant. However, it is still possible to clearly observe the contribution of stearyl stearate in improving this aspect. Table 4. Results of oxygen barrier (Oxygen Transmission Rate) at 0% of relative humidity using a medium fibrillated MFC.

[0088] (*>No = Not possible to measure OTR due oxygen permeability above the limit of quantification of the equipment. Table 5. Results of oxygen barrier (Oxygen Transmission Rate) at 50% of relative humidity using a medium fibrillated MFC.

[0089] (*>No = Not possible to measure OTR due oxygen permeability above the limit of quantification of the equipment.

Claims

CLAIMS1. An oil and grease and oxygen barrier composition comprising MFC and stearyl stearate.

2. The oil and grease and oxygen barrier composition of claim 1 , comprising at least 95% wt. of MFC of the dry total weight of the oil and grease and oxygen barrier composition and 5% wt. or less of stearyl stearate, preferably 0,5-5% wt. of stearyl stearate, of the dry total weight of the dry oil and grease and oxygen barrier composition.

3. The oil and grease and oxygen barrier composition of any one of the preceding claims, further comprising alkyl ketene dimer (AKD), wherein the AKD is one selected from: solid alkyl ketene dimer AKD, liquid alkyl ketene dimer (L-AKD), or mixtures thereof.

4. The oil and grease and oxygen barrier composition of claim 3, comprising up to 10 % wt. of alkyl ketene dimer (AKD), of the dry total weight of the dry oil and grease and oxygen barrier composition.

5. The oil and grease and oxygen barrier composition of claim 3, comprising up to 10 % wt. of liquid AKD, of the dry total weight of the oil and grease and oxygen barrier dry composition.

6. The oil and grease and oxygen barrier composition of any one of the preceding claims, wherein the oil and grease and oxygen barrier composition is incorporated into a cellulose pulp and / or applied to at least a surface of a cellulosic substrate.

7. The oil and grease and oxygen barrier composition of claim 6, wherein the oil and grease and oxygen barrier composition applied to at least a surface of a cellulosic substrate is 2-20 gsm.

8. The oil and grease and oxygen barrier composition of any one of the claims 6-7, wherein the oil and grease and oxygen barrier composition incorporated to a cellulosic substrate is 6-72 kg / ton of cellulosic substrate.

9. The oil and grease and oxygen barrier composition of any one of claims 6-8, wherein the cellulosic substrate is a paper, a cardboard, a containerboard, a flexible paper, a molded pulp packaging, a film and others, as well as disposable products produced from these materials.10.A process for producing a cellulosic substrate having an oil and grease and oxygen barrier composition defined in claim 1 , wherein the oil and grease and oxygen barrier composition is applied to at least one or more of a surface of a wet pulp; a surface of a pre-dried cellulosic substrate.

11. The process for producing a cellulosic substrate having an oil and grease and oxygen barrier composition of claim 10, wherein the wet pulp or the pre-dried cellulosic substrate is converted into a sheet of paper.12.The process for producing a cellulosic substrate having an oil and grease and oxygen barrier composition of claims 10 or 1 1 , wherein the oil and grease and oxygen barrier composition is applied to a surface of a wet pulp or to a surface of a pre-dried cellulosic substrate, or both, by a dosing system as size press, Film press, size press, Spray bar, coating system or any other suitable dosing system.13.The process for producing a paper having an oil and grease and oxygen barrier composition of claims 10 -12, wherein the oil and grease and oxygen barrier composition is incorporated to the furnish during the pulp stock preparation.14.The process for producing a cellulosic substrate having an oil and grease and oxygen barrier composition of claims 10-13, wherein the furnish is converted into a sheet of paper.15.A paper article having an oil and grease and oxygen barrier composition comprising a cellulosic substrate and having at least one surface, wherein at least one surface is covered with a layer of the oil and grease and oxygen barrier composition defined in claims 1 - 9.

16. An oil and grease and oxygen bi-layer barrier comprising an internal layer in contact with a surface of a cellulosic substrate and an external layer.17.The oil and grease and oxygen bi-layer barrier of claim 16, wherein the internal layer comprises MFC at least 85% wt. of the dry total weight of the internal layer of the oil and grease oxygen bi-layer barrier.18.The oil and grease and oxygen bi-layer barrier of claims 16-17, wherein the internal layer comprises MFC between 90 - 100 % wt. of the dry total weight of the internal layer of the oil and grease and oxygen bi-layer barrier.19.The oil and grease and oxygen bi-layer barrier of claims 16-18, wherein the internal layer further comprises up to 10% wt. of AKD of the dry total weight of the internal layer of the oil and grease and oxygen bi-layer barrier.20.The oil and grease and oxygen bi-layer barrier of claim 16, wherein the external layer comprises stearyl stearate at least at 90 % wt. of the dry total weight of the external layer of the oil and grease and oxygen bi-layer barrier.

21. The oil and grease and oxygen bi-layer barrier of claims 16 or 20, wherein the external layer comprises stearyl stearate between 95 - 100 % wt. of the dry total weight of the external layer of the oil and grease and oxygen bi-layer barrier.22.The oil and grease and oxygen bi-layer barrier of claim 19, wherein the AKD is one selected from: solid alkyl ketene dimer AKD, liquid alkyl ketene dimer (L- AKD), or mixtures thereof.23.The oil and grease and oxygen bi-layer barrier of any one of claims 16-22, wherein the oil and grease and oxygen bi-layer barrier is 2 - 24 gsm.24.The oil and grease and oxygen bi-layer barrier of any one of claims 16-23, wherein the internal layer is 2 - 20 gsm.25.The oil and grease and oxygen bi-layer barrier of any one of the claims 16-24, wherein the external layer is up to 4 gsm.26.A process for producing a cellulosic substrate having an oil and grease and oxygen bi-layer barrier defined in claim 16, wherein the internal layer of the oil and grease and oxygen bi-layer barrier is applied to a surface of a pre-dried cellulosic substrate and the external layer of the oil and grease and oxygen bi- layer barrier is applied onto the internal barrier.27.The process of claim 26, wherein the internal layer of the oil and grease and oxygen bi-layer barrier is applied to a surface of a wet pulp and the external layer of the oil and grease and oxygen bi-layer barrier is applied onto the internal barrier.28.The process of claim 27, wherein the internal layer of the oil and grease and oxygen bi-layer barrier is applied to a surface of a wet pulp by a dosing system such as Film press, size press, Spray bar, coating system or any other suitable dosing system and the external layer of the oil and grease and oxygen bi-layer barrier is applied onto the internal barrier by size press and or by a dosing system such as Film press, size press, Spray bar, coating system or any other suitable dosing system.29.The process of any one of claim 26-28, wherein the internal layer of the oil and grease and oxygen bi-layer barrier is applied to a surface of a pre-dried cellulosic substrate by a dosing system such as Film press, size press, Spray bar, coating system or any other suitable dosing system and the external layer of the oil and grease and oxygen bi-layer barrier is applied onto the internal barrier by a dosing system such as Film press, size press, Spray bar, coating system or any other suitable dosing system.

30. A paper article having oil and grease and oxygen bi-layer barrier defined in claim 16, comprising a cellulosic substrate and having at least one surface, wherein the at least one surface is covered with a layer of an oil and grease and oxygen bi-layer barrier.

31. The paper article of claim 30, comprising a grease barrier Kit of at least 7, preferably 9-12, as determined using TAPPI T 559 standard.32.The paper article from claim 30, comprising an oxygen transmission rate of <100 cc / (m2.Day), preferably < 30 cc / (m2.Day), at 0% relative humidity.

33. A paper article of claims 30 - 32, wherein the paper article is one of a recyclable oil and grease resistant paper, a renewable oil and grease resistant paper or a home compostable oil and grease resistant product; preferably for consumer food products.34.The paper article of claims 30 - 33, wherein the paper has an improved oil and grease and oxygen bi-layer barrier.

39. The paper article of claims 30 - 34, wherein the paper is a paper for consumer food products.

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