Oil and water repellent cellulose-based material and use thereof

Abstract

The present invention is directed to a cellulose based (composite) material comprising non-modified cellulose fibers in contact with the cationic polymer, sizing agent and optionally the surface modifying agent. Further, method of manufacturing of the cellulose-based material and article comprising same are also provided.

Description

OIL AND WATER REPELLENT CELLULOSE-BASED MATERIAL AND USE THEREOF CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 744,886, filed on January 14, 2025, entitled “OIL AND WATER REPELLENT CELLULOSE-BASED MATERIAL AND USE THEREOF”. The contents of the above application are all incorporated by reference as if fully set forth herein in their entirety.FIELD OF THE INVENTION

[0002] The invention relates generally to the field of oil and water repellent cellulose-based materials comprising modified cellulose fibers and to articles comprising same.BACKGROUND OF THE INVENTION

[0003] Packaging made of natural cellulose fibers suffers from poor properties of repelling water and oil. Water and oil repellent packaging based on synthetic polymers or synthetic laminates are commonly utilized as food packaging for oily and wet food.

[0004] Usually hydrophilic cellulose-based materials undergo surface treatment by water and oil repellent reagents, such as fluorocarbon based agents. Recently water and oil repellent packages containing fluoro-resins drew a concern about its safety.

[0005] Thus, there is a need for food safe and environmentally friendly cellulose-based materials characterized by combined oil and water repellent properties, especially for use as food packages.SUMMARY OF THE INVENTION

[0006] In one aspect of the present invention, there is provided a material comprising cellulose fibers in contact with a cationic polymer and a surface modifying agent selected from Polyvinyl alcohol (PVA), abietic acid, melamine formaldehyde, urea formaldehyde and pinic acid, including any combination, any salt, and any derivative thereof.

[0007] In one embodiment, a w / w portion of the cationic polymer relative to the dry weight of the cellulose fibers is between about 0.1 and about 10%; and wherein a w / w portion of the surface modifying agent relative to the dry weight of the cellulose fibers is between about 1 and about

[0008] In one embodiment, the surface modifying agent is covalently bound to the cellulose fibers.

[0009] In one embodiment, the cellulose fibers comprise natural cellulose fibers derived from a plant biomass, and wherein between 80 and 100% w / w of the polymeric content of the plant biomass consists of cellulose, lignin or hemicellulose or any combination thereof.

[0010] In one embodiment, the plant biomass comprises bagasse and wherein the material is a non-woven material.

[0011] In one embodiment, the cellulose fibers are coated by the cationic polymer and the surface modifying agent.

[0012] In one embodiment, the cationic polymer is or comprises any one of polyethylene imine (PEI), poly(amidoamine dendrimer) (PAMAM) and Poly(dimethylamine ethyl methacrylate) (PDMAEME), including any mixture, and any co-polymer thereof.

[0013] In one embodiment, the PEI is selected from a branched and a linear PEI and is characterized by average MW of between 60.000 and 1.000.000 Da.

[0014] In one embodiment, the PEI is a non-modified PEI; and wherein a w / w portion of the nonmodified PEI relative to the dry weight of the cellulose fibers is between about 0.1 and about 5%.

[0015] In one embodiment, the material further comprises a sizing agent in an amount ranging between 1 and 20% relative to the dry weight of the cellulose fibers.

[0016] In one embodiment, the sizing agent is selected from alkyl ketene dimer, butyl acrylate, including any copolymer thereof, styrene acrylate co-polymer, alkenyl succinic anhydride, alkenyl succinic acid, including any combination and any salt thereof.

[0017] In one embodiment, the material further comprises a colorant.

[0018] In one embodiment, a w / w concentration of the colorant within the material is between 0.1 and 5% relative to the dry weight of the cellulose fibers; and wherein the colorant is an inorganic pigment.

[0019] In one embodiment, the material further comprises an acid and / or a salt thereof, wherein a w / w concentration of the acid within the material is between 0.1 and 5% relative to the dry weight of the cellulose fibers.

[0020] In one embodiment, the cellulose fibers, the cationic polymer, the surface modifying agent, and optionally the sizing agent are uniformly distributed within the material.

[0021] In one embodiment, the material is an oil and water repellent material characterized by (i) water absorbency below 100 g / m2, as determined by Cobb test performed for 30min; and / or by (ii) oil absorbency below 90 g / m2, as determined by Cobb test performed for 30min.

[0022] In one embodiment, the material is characterized by oil absorption time of at least Ih, as determined by oil drop test.

[0023] In another aspect, there is provided an article comprising the material of the invention, or wherein the article is shaped from the material of the invention.

[0024] In one embodiment, the article is in a form of a ribbon, a sheet, a film, a packaging material, a thread, a container, or any combination thereof.

[0025] In one embodiment, the article is a food package or a dishware. In one embodiment, the article is shaped by subjecting the material to a hot press processing.

[0026] In another aspect, there is provided a method of manufacturing the material of the invention, comprising mixing a cellulose-based material in an aqueous medium with (i) the cationic polymer and (ii) the surface modifying agent under suitable conditions, thereby obtaining a mixture; separating the mixture, to obtain a wet material; and drying the wet material.

[0027] In one embodiment, a w / w concentration of the cellulose-based material in the aqueous medium in step i is between 1 and 5%.

[0028] In one embodiment, the step i further comprising diluting the mixture with an additional amount of the aqueous medium sufficient for obtaining a w / w concentration of the cellulose-based material ranging between 0.6 and 1%. In one embodiment, the step i further comprising diluting the mixture with an additional amount of the aqueous medium sufficient for obtaining a w / w concentration of the cellulose-based material ranging between 0.2 and 1%.

[0029] In one embodiment, a w / w ratio between the cellulose-based material and the cationic polymer within the mixture is between about 0.5 and 6%; and wherein a w / w ratio between the cellulose-based material and the surface modifying agent within the mixture is between about 1 and about 10%.

[0030] In one embodiment, step i further comprises adding the colorant to the mixture and optionally at least one of the sizing agent and the acid.

[0031] In one embodiment, the cellulose-based material is in a form of fibers characterized by an average length of between 10 and 5000um.

[0032] In one embodiment, separating is by filtration and wherein the process further comprising shaping the wet material; and wherein shaping and drying are performed simultaneously or subsequently.

[0033] In one embodiment, drying is performed by a hot press.

[0034] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains.

[0035] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0036] Further embodiments and the full scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.DETAILED DESCRIPTION OF THE INVENTION

[0037] In one aspect of the invention, there is provided a material comprising cellulose fibers, wherein the cellulose fibers are in contact with a cationic polymer and a sizing agent.

[0038] In another aspect of the invention, there is provided a material comprising a plurality of cellulose fibers, wherein the material is a fibrous material (i.e. woven or non-woven fibrous material, also referring to as a “textile material” or a “fabric”); wherein the fibrous material comprises or consists essentially of (i) cellulose fibers, (ii) a cationic polymer and (iii) a sizing agent.

[0039] In some embodiments, the material is a woven or a non-woven material. In some embodiments, the material is a non-woven material. In some embodiments, the cellulose based material is derived from a natural material.

[0040] In some embodiments, the material further comprises a sizing agent. In some embodiments, the sizing agent is stably bound to the cellulose fibers. In some embodiments, the sizing agent is homogenously distributed within the material of the invention.

[0041] The term “stable" refers to the ability of the sizing agent to remain attached to the cellulose fibers. Specifically, the sizing agent is stably bound to the cellulose fiber when at least 80%, or at least 90% of the initial amount of the sizing agent within the material of the invention is retained upon contacting thereof with a liquid (e.g. a liquid food product). In some embodiments, the sizing agent is adsorbed to the material (e.g. by physisorption).

[0042] In some embodiments, the sizing agent is or comprises any sizing agent known in the textile or paper industry. Various sizing agents are known in the art, such as surface sizing agentand internal sizing agent is selected from alkyl ketene dimer (AKD), butyl acrylate including any copolymer thereof, styrene acrylate co-polymer, alkenyl succinic anhydride, alkenyl succinic acid, including any combination and any salt thereof. In some embodiments, the sizing agent is or comprises AKD.

[0043] In some embodiments, a w / w concentration of the sizing agent within the material is between 0.5 and 20%, between 0.5 and 10%, between 0.5 and 2%, between 0.5 and 3%, between 0.5 and 0.8%, between 0.8 and 5%, between 0.8 and 3%, between 0.8 and 2%, between 0.8 and 1%, between 1 and 20%, between 1 and 10%, between 1 and 5%, between 1 and 3%, between 1 and 2%, between 5 and 20%, between 5 and 10%, between 5 and 15%, including any range between.

[0044] In some embodiments, a w / w concentration of the sizing agent within the material is between 0.5 and 20%, between 0.5 and 10%, between 0.5 and 2%, between 0.5 and 3%, between 0.5 and 0.8%, between 0.8 and 5%, between 0.8 and 3%, between 0.8 and 2%, between 0.8 and 1%, between 1 and 20%, between 1 and 10%, between 1 and 5%, between 1 and 3%, between 1 and 2%, between 5 and 20%, between 5 and 10%, between 5 and 15%, including any range between; and wherein the sizing agent is AKD.

[0045] In some embodiments, the cellulose fibers are derived from natural cellulose. In some embodiments, the cellulose fibers are derived from a plant based material. In some embodiments, the plant based material has a cellulose content of at least 10%, at least 20%, at least 40%, at least 50%, at least 60%w / w, including any range between. In some embodiments, the cellulose fibers are in a form of yams or in a form of textile fibers.

[0046] The term “fiber” refers to individual strand of plant-based cellulose having a length dimension which is significantly longer than it is width dimension. Fibers are the basic building blocks of textiles and can be spun into yams. Fibers typically have a small diameter of few micrometers (e.g. 1-20, or l-50pm, including any range between).

[0047] In some embodiments, the cellulose fibers are characterized by an average length between 10 and 5000 um, between 10 and 4000 um, between 10 and 3000 um, between 30 and 5000 um, between 30 and 3000 um, between 50 and 5000 um, between 50 and 3000 um, including any range between. The fiber length is determined by Optical Microscopy together with an appropriate Image Analysis Software. Exemplary device for measuring fiber distribution is MorFi Neo device.

[0048] The term “yam” refers to a continuous length of interlocked fibers. Yams can be used in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, and ropemaking. The diameter of yam is typically in the range of from about 100 micrometers to severalmillimeters (e.g. between 50um and 5mm, including any range between). Yams are usually divided into 3 categories based on their diameter: Fine Yams: These are often used in lightweight fabrics such as silk or fine cotton and can have diameters as small as 0.1 to 0.2 millimeters (100 to 200 micrometers); Medium Yams: Commonly used in standard cotton or wool fabrics, these yams typically have diameters ranging from 0.2 to 0.5 millimeters (200 to 500 micrometers); and Thick Yams: Used in heavier fabrics such as denim or upholstery, these yams can have diameters ranging from 0.5 millimeters to several millimeters (e.g. 0.5-10, or 0.5-5 mm).

[0049] In some embodiments, the cellulose fibers are derived from a natural plant material. In some embodiments, the natural material is a plant biomass. In some embodiments, the cellulose fibers derived from a natural material resemble the chemical structural of the natural cellulose. It should be apparent to a killed artisan that the term “cellulose fibers” encompasses cellulose-based fibers (e.g. natural cellulose based fibers) composing further to cellulose additional polymers such as lignin and hemicellulose.

[0050] In some embodiments, a polymeric content of the cellulose fibers derived from a natural material (i.e. total polymeric material of the cellulose fibers disclosed herein) consist essentially of cellulose, hemicellulose, and lignin. In some embodiments, a polymeric content of the material of the invention consist essentially of cellulose, hemicellulose, and lignin.

[0051] In some embodiments, between 70 and 99%, between 80 and 100%, between 75 and 90%, between 80 and 95%, between 70 and 80%, between 70 and 95%, between 70 and 90%, between 95 and 99%w / w of the polysaccharide content of the material disclosed herein consist of cellulose and hemicellulose. In some embodiments, between 80 and 100%, between 85 and 99%, between 90 and 100%, between 90 and 99%, between 95 and 99%w / w of the polysaccharide content of the cellulose fibers disclosed herein consist of cellulose and hemicellulose.

[0052] In some embodiments, between 80 and 100%, between 85 and 99%, between 90 and 100%, between 90 and 99%, between 95 and 99%w / w of the polysaccharide content of the modified cellulose fibers disclosed herein consist of cellulose and hemicellulose.

[0053] Natural cellulose is a polysaccharide composed of repeating units of P-D-glucose. The chemical structure of cellulose can be described as follows: (i) a linear polymer composed essentially of cellobiose repeating unit, which consists of two P-D-glucose molecules linked by a P(1 — 4) glycosidic bond; (ii) the polymer chains are arranged in microfibrils formed by hydrogen bonds between adjacent polymers; and (iii) having an average degree of polymerization ranging between 100 and 50000 glucose units, including any range between.

[0054] Natural cellulose refers to cellulose that is derived directly from plant sources without undergoing significant chemical modification. It retains its original molecular structure andproperties as found in nature. Examples of natural cellulose include cellulose extracted from wood pulp, cotton, and other plant fibers. Natural cellulose is biodegradable and environmentally friendly.

[0055] In some embodiments, the plant biomass is derived from a plant or plant part (e.g. stem, branch, seed, root, etc.). Exemplary plant biomass comprises bagasse, Eucalyptus biomass, bamboo biomass, coffee biomass, hemp biomass, grass biomass, wheat biomass, wood biomass, cotton biomass, Flax biomass, Jute biomass, Sisal biomass, Kenaf biomass, Rice straw biomass, Sorghum biomass, Banana stem biomass, Pineapple leaf biomass, Alfalfa biomass, or any combination thereof. In some embodiments, wood biomass includes softwood-derived biomass (e.g., pine, spruce, fir, cedar) and hardwood-derived biomass (e.g., oak, maple, birch, beech, poplar), or any combination thereof. Softwood and hardwood biomass differ in their cellulose characteristics and associated lignin content. Softwood is typically derived from coniferous trees such as pine and spruce and generally has higher lignin content. Hardwood is derived from deciduous trees such as oak, birch, and maple, and has lower lignin content compared to softwoods.

[0056] The term “bagasse” is the fibrous residue that remains after the extraction of juice from sugarcane or sorghum stalks. It is primarily composed of cellulose, hemicellulose, and lignin, making it a valuable byproduct for various industrial applications. Bagasse is typically used as a raw material for the production of paper, cardboard, and biofuels, as well as in the manufacture of biodegradable packaging materials and building materials.

[0057] In some embodiments, the plant biomass is processed or unprocessed. A “processed plant biomass” encompasses any industrial plant biomass treatment process, such as washing, boiling, bleaching, grinding, cutting, pressing, scouring, mercerization, Kraft process, etc. In some embodiments, the plant biomass is a non-modified biomass, comprising or consisting essentially of non-modified (i.e. without any chemical modification) cellulose.

[0058] In some embodiments, the material disclosed herein comprises (i) cellulose fibers, (ii) the cationic polymer and (iii) the sizing agent disclosed herein. In some embodiments, the material disclosed herein further comprises (iv) a surface modifying agent. In some embodiments, i, ii and iii and optionally iv are intermixed within the entire material volume. In some embodiments, ii and iii and optionally iv are uniformly distributed within the entire material volume or within a cellulose fiber matrix. Uniform distribution can be determined by chemical analysis (such as HPLC, GPC, GC / LC-MS), for example based on 3 samples taken from the tested material and calculation of an average concentration of each material constituent. A deviation of theconcentration of each of the constituents in any of the samples from the average concentration being below 20% or below 15% is indicative of uniform distribution.

[0059] In some embodiments, the cellulose fibers are in contact with or non- covalently bound to the cationic polymer, the sizing agent and optionally to the surface modifying agent. In some embodiments, the material disclosed herein is devoid of chemically modified cellulose fibers. In some embodiments, the cationic polymer and optionally the surface modifying agent is / are adsorbed to the cellulose fibers. In some embodiments, the cationic polymer and optionally the sizing agent and / or the surface modifying agent is / are bound to the cellulose fibers via non-covalent bonds, such as Van-der-Walls interactions, dipole-dipole interactions, hydrogenbonding, electrostatic interactions, or any combination thereof.

[0060] The term “composite” as used herein refers to a material (e.g. a solid material) in a form of a homogenous mixture of the entire constituents (e.g. the cellulose fibers, the cationic polymer and the sizing agent and optionally the surface modifying agent), wherein the constituents a stably bound to each other and cannot be separated by conventional means. The composite is characterized by distinct physical properties (e.g. oil-repellence, and water-repellence) as compared to the physical properties of the individual constituents or as compared to pristine cellulose fibers.

[0061] In some embodiments, the fibers of the material disclosed herein consist essentially of natural cellulose fibers bound to the cationic polymer and the sizing agent and optionally to the surface modifying agent, disclosed hereinbelow. In some embodiments, the fibers of the material disclosed herein consist essentially of natural cellulose fibers coated by the cationic polymer and the sizing agent and optionally by the surface modifying agent. In some embodiments, the cationic polymer, the sizing agent and optionally the surface modifying agent are located on the outer portion of the cellulose fiber (i.e. the outer portion refers to a portion facing the ambient, corresponding to up to 20% of the fiber’s diameter). In some embodiments, the inner portion of the cellulose fiber (i.e. the core portion corresponding to at least 50% of the fiber’s diameter) is composed essentially of unmodified cellulose.

[0062] In some embodiments, the cellulose fiber content by dry weight of the material disclosed herein is between 50 and 90%, between 50 and 80%, between 60 and 80%, between 70 and 90%, including any range between.

[0063] In some embodiments, the cationic polymer is an ionizable polymer. In some embodiments, the ionizable polymer is capable of undergoing ionization (positive ionization) within a solution having a pH value below the pKa value of the amine group of the ionizable polymer. In some embodiments, the ionizable polymer is capable of undergoing protonationwithin a solution having a pH value below the pKa value of the amine group of the ionizable polymer. In some embodiments, at least 50% by weight of the ionizable polymer is positively charged (or protonated) within a solution having a pH value below the pKa value of the amine group of the ionizable polymer. In some embodiments, the ionizable polymer is a polycationic polymer. In some embodiments, the ionizable polymer undergoes multiple protonation within a solution, wherein the solution is as described herein.

[0064] In some embodiments, the cationic polymer is a polyamine. In some embodiments, the cationic polymer is an amine-based polymer. In some embodiments, the cationic polymer comprises a primary amine group, a secondary amine group, a tertiary amine group, or any combination thereof. In some embodiments, the cationic polymer comprises a plurality of permanent positive charges, such as a plurality of tertiary amine groups.

[0065] In some embodiments, the polyamine or the amine-based polymer comprises any one of a polylysine, a polyarginine, a polyhistidine, chitosan, polyethyleneimine (PEI), poly(amidoamine dendrimer) (PAMAM) and Poly(dimethylamine ethyl methacrylate) (PDMAEME), including any mixture, and any co-polymer thereof.

[0066] In some embodiments, the cationic polymer is or comprises polyethyleneimine (PEI). In some embodiments, the PEI is or comprises a linear PEI. In some embodiments, the PEI is or comprises a branched PEI. In some embodiments, the PEI is or comprises a chemically modified PEI.

[0067] Examples of chemically modified PEI include but are not limited to a chemical modification selected from: Hexanedioic acid, N-(2-aminoethyl)- 1,3 -propanediamine, aziridine, (chloromethyl)oxirane, 1,2-ethanediamine, N,N-l,2-ethanediylbisl,3-propanediamine, formic acid and . alpha. -hydro-.omega.-hydroxypoly(oxy-l,2-ethanediyl).

[0068] In some embodiments, the PEI is or comprises a branched non-modified PEI. In some embodiments, the PEI is or comprises a linear non-modified PEI.

[0069] In some embodiments, the PEI is characterized by average molecular weight between 50.000 and 1.000.000, between 60.000 and 1.000.000, between 80.000 and 1.000.000, between 100.000 and 1.000.000, between 200.000 and 1.000.000, between 500.000 and 1.000.000, including any range between.

[0070] The term “average molecular weight” encompasses weight average molecular weight (Mw) or number average molecular weight (Mn). As used herein, the term "weight average molecular weight" generally refers to a molecular weight measurement that depends on the contributions of oligomer molecules according to their sizes. As used herein, the term "number average molecular weight" generally refers to a molecular weight measurement that iscalculated by dividing the total weight of all the oligomer molecules in a sample with the total number of oligomer molecules in the sample. These terms are known by those of ordinary skill in the art. The average molecular weight is determined by Gel permeation chromatography (GPC), by viscosity or by MALDI.

[0071] In some embodiments, a w / w portion of the cationic polymer relative to the dry weight of the cellulose fibers within the material of the invention is between about 0.1 and about 10%, between about 0.1 and about 5%, between about 0.5 and about 5%, between about 4 and about 10%, between about 5 and about 10%, between about 1 and about 10%, between about 1 and about 5%, between about 2 and about 10%, between about 3 and about 10%, between about 2 and about 5%, between about 3 and about 6%, between about 2 and about 6%, between about 1 and about 6%, including any range between.

[0072] In some embodiments, a w / w concentration of the surface modifying agent within the material is between 0.5 and 20%, between 0.5 and 10%, between 0.5 and 2%, between 0.5 and 3%, between 0.5 and 0.8%, between 0.8 and 5%, between 0.8 and 3%, between 0.8 and 2%, between 0.8 and 1%, between 1 and 20%, between 1 and 10%, between 1 and 5%, between 1 and 3%, between 1 and 2%, between 5 and 20%, between 5 and 10%, between 5 and 15%, including any range between. In some embodiments, a w / w portion of the surface modifying agent relative to the dry weight of the cellulose fibers within the material of the invention is between about 1 and about 10%, between about 3 and about 10%, between about 3 and about 10%, is between about 4 and about 10%, is between about 4 and about 8%, is between about 2 and about 8%, between about 4 and about 6%, between about 4 and about 10%, including any range between.

[0073] In some embodiments, the surface modifying agent is covalently bound to the cellulose molecules via an ester bond. In some embodiments, the surface modifying agent is configured to reduce water absorbency and oil absorbency of the pristine cellulose-based material (i.e. the same cellulose based material devoid of surface modifying agent). In some embodiments, the surface modifying agent is configured to reduce water absorbency and oil absorbency of the pristine cellulose-based material, to provide oil and water repellent properties to the material, as disclosed herein. In some embodiments, the surface modifying agent is configured to enhance oil and water repellent properties provided to the cellulose fibers by the cationic polymer.

[0074] In some embodiments, the surface modifying agent has a functional group capable of reacting with cellulose to form a covalent bond or a coordinative bond therewith. In some embodiments, the functional group is selected from carboxy, hydroxy, amino, mercapto, ester,halo, or any combination thereof. In some embodiments, the material is devoid of surface modifying agent covalently bound to the cellulose fibers.

[0075] In some embodiments, the surface modifying agent is selected from Polyvinyl alcohol (PVA), a non-cellulose polysaccharide, a cellulose derivative, a metal / metalloid oxide particle, glycerin, abietic acid and pinic acid, melamine formaldehyde, urea formaldehyde, including any combination, any salt, and any derivative thereof. In some embodiments, the metal / metalloid oxide particle is selected from, zirconia, titania, alumina and silica, including any combination thereof. In some embodiments, the metal / metalloid oxide particle is characterized by an average particle size between 1 and 500um.

[0076] In some embodiments, the non-cellulose polysaccharide is selected from starch, chitosan, guar gum, Xanthan gum, carrageenan, pectin, alginate, including any mixture, copolymer and any salt thereof.

[0077] In some embodiments, the cellulose derivative is selected from Carboxymethyl cellulose (CMC), Hydroxyethyl cellulose, and Methyl cellulose, including any mixture, copolymer and any salt thereof.

[0078] In some embodiments, the surface modifying agent is or comprises Rosin, (e.g. natural extract or at least partially purified or pre-treated natural Rosin). In some embodiments, the surface modifying agent is or comprises Polyvinyl alcohol (PVA) and glycerin. In some embodiments, the surface modifying agent is selected from metal / metalloid oxide particle, CMC, alginate, PVA and Rosin, including any combination thereof.

[0079] In some embodiments, between 70 and 99%, between 80 and 100%, between 75 and 90%, between 80 and 95%, between 70 and 80%, between 70 and 95%, between 70 and 90%, between 95 and 99% by dry weight of the material consists of the cellulose fibers, the sizing agent and optionally the surface modifying agent.

[0080] In some embodiments, the material of the invention is as described herein, wherein the surface modifying agent is Rosin present at a concentration between about 2-10% within the material; wherein the cationic polymer is a branched PEI (having an average MW between 500 and 1000 KDa) present at a concentration between about 2-5%w / w within the material; and the sizing agent (AKD) present at a concentration between about 1-5% within the material.

[0081] In some embodiments, the material of the invention further comprises a colorant. The term “colorant” is well known in the art as a substance used to impart color to materials. Colorants include dyes, pigments, and other substances that change the color of an object or material.

[0082] In some embodiments, the colorant present in the material of the invention is a pigment (i.e. an inorganic salt or inorganic compound). In some embodiments, the colorant is or comprises an inorganic pigment. In some embodiments, the inorganic pigment is or comprises any one of: metal oxide pigment (exemplary species are listed below), Silicate pigment (e.g. Ultramarine: Aluminosilicate Pigment (Nas-ioAleSieC^S?-^, Egyptian Blue: Copper silicate Pigment (CaCuSi4Oio)); Carbonate pigment (e.g. Malachite: Copper carbonate hydroxide (CmCCMOHh), Azurite: Copper carbonate hydroxide (Cus^Ch OH)?)); Phosphate pigment (Cobalt Violet: Cobalt(II) phosphate (Cos PCb)?)); Sulfide pigment (e.g. Zinc Sulfide: Zinc sulfide (ZnS)); and Mixed Metal Oxide pigment (e.g. YInMn Blue: Yttrium indium manganese oxide (YimxMnx03), Cobalt Blue: Cobalt(II) aluminate (COAI2O4), Cobalt Green: Cobalt(II) zincate (CoZnO?)).

[0083] Exemplary inorganic pigments (metal oxide pigments) include but are not limited to: Iron Oxide Pigments (e.g. Red Iron Oxide: Hematite (Fe2O3), Yellow Iron Oxide: Goethite (FeO(OH)), Black Iron Oxide: Magnetite (FesO4)), Chromium Pigments (e.g. Chrome Green: Chromium(III) oxide (C Ch)), Cobalt Pigments (e.g. Cobalt Blue: Cobalt(II) aluminate (COAI2O4), Cobalt Green: Cobalt(II) zincate (CoZnO2)), Titanium Dioxide (e.g. Titanium White: Titanium dioxide (TiO2)), and Zinc pigments (e.g. Zinc Oxide (ZnO)).

[0084] The particle size of inorganic pigments is a critical parameter that influences their color strength, opacity, and dispersion properties. Several techniques are used to determine the particle size . Common methods include: Laser Diffraction (Suitable for particles ranging from nanometers to millimeters), Dynamic Light Scattering (DLS) (Typically used for particles in the range of 1 nm to 1 pm), Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) (Suitable for particles from a few nanometers to several micrometers), Sedimentation Techniques (Suitable for particles from a few nanometers to several micrometers), Sieving (Suitable for particles from a few micrometers to several millimeters) and X-ray Diffraction (XRD) (Suitable for particles from a few nanometers to several micrometers).

[0085] In some embodiments, the inorganic pigment is in a form of a particulate matter, characterized by an average particle size between lOnm and lOum, between lOnm and 2um, between 50nm and 2um, between lOOnm and 2um, between lOnm and lOOnm, between 50nm and lOOnm, between lOOnm and 5um, between lOOnm and lum, between 0.1 and lOum, between 0.5 and lOum, between 0.7 and lOum, between 0.5 and 5um, between 0.7 and 5um, including any range between. The particle size of inorganic pigments can vary widely depending on the application and desired properties. Generally, the particle size ranges from a few nanometers to several micrometers. Typical particle size ranges for inorganic pigments are: Nanoparticles: Less than 100 nm. These are used for applications requiring high transparency and UV protection. FineParticles: 100 nm to 1 pm. These are commonly used in coatings and plastics for their good dispersion and color strength. Coarse Particles: 1 pm to 10 pm.

[0086] In some embodiments, the inorganic pigment is or comprises an iron oxide pigment and is characterized by an average particle size between 50nm and 2um, or between lOOnm and lum.

[0087] In some embodiments, a w / w concentration of the colorant within the material is between 0.1 and 5% relative to the dry weight of the cellulose fibers.

[0088] In some embodiments, a w / w concentration of the inorganic pigment within the material is between 0.1 and 5%, between 0.1 and 3%, between 0.5 and 5%, between 0.5 and 3%, between 0.5 and 4%, between 0.5 and 2%, between 1 and 5%, between 1 and 2%, between 1 and 3%, between 1 and 4%, relative to the dry weight of the cellulose fibers, including any range between.

[0089] In some embodiments, the material of the invention further comprises an acid and / or a salt thereof, wherein a w / w concentration of the acid within the material is between 0.1 and 5% relative to the dry weight of the cellulose fibers. In one embodiment, the acid comprises any one of citric acid, acetic acid, malic acid, succinic acid, tartaric acid, malonic acid, glutaric acid, adipic acid, or any strong acid such as nitric acid, sulfuric acid and phosphoric acid, including any salt or any combination thereof.

[0090] In some embodiments, the material is a composite material consisting essentially of (i) cellulose fibers having an average length disclosed hereinabove, (ii) the cationic polymer PEI, (iii) the surface modifying agent disclosed hereinabove, (iv) the sizing agent and (v) the inorganic pigment, wherein the w / w concentration of each of the constituents within the material is as disclosed hereinabove. In some embodiments, the materials (i)-(v) constitute between 70 and 99%, between 80 and 100%, between 75 and 90%, between 80 and 95%, between 70 and 80%, between 70 and 95%, between 70 and 90%, between 95 and 99% by dry weight of the material.

[0091] In some embodiments, the material or the article of the invention is characterized by improved oil repellency and / or water repellency, as compared to cellulose fibers solely treated by the sizing agent and the surface modifying agent (i.e. without the cationic polymer).

[0092] In some embodiments, improved comprises at least 10%, at least 20%, at least 50%, at least 80% improved oil repellency, as determined by Cobb test. In some embodiments, improved comprises at least 2 fold, or between 2 and 3 fold reduced oil absorbency, as compared to a similar material solely treated by the sizing agent as determined by Cobb test. In some embodiments, improved comprises at least 2 fold, at least 5 fold, at least 10 fold, at least 20 fold, or between 2 and 30 fold increased oil repellency, as compared to a similar material solely treated by the sizing agent as determined by oil drop test (or water drop test).

[0093] In some embodiments, the material or the article of the invention is characterized by water absorbency below 100 g / m2, below 90 g / m2, below 85 g / m2, between 70 and 90 g / m2, between 70-85 g / m2, including any range between, as determined by Cobb test performed for 30min.

[0094] In some embodiments, the material or the article of the invention is characterized by oil absorbency below 100 g / m2, below 90 g / m2, below 85 g / m2, below 70 g / m2, below 60 g / m2, between 50-90 g / m2, between 50-85 g / m2, between 55-85 g / m2, including any range between, as determined by Cobb test performed for 30min.

[0095] In some embodiments, the material or the article of the invention is characterized by oil absorption time of at least Ih, at least 2h, at least 3h, at least 4h, or between 2 and 4.5h, as determined by oil drop test.

[0096] In another aspect, there is provided an article comprising the material of the invention. In some embodiments, the article is shaped from the material disclosed herein. In some embodiments, the article comprises one or more layer(s), wherein at least one layer comprises the material of the invention.

[0097] In some embodiments, the article is in a form of a ribbon, a sheet, a film, a packaging material, a thread, a container, or any combination thereof. In some embodiments, the article comprises at least one wall, wherein the wall comprises the material of the invention.

[0098] In some embodiments, the article is a food package. In some embodiments, at least 80%, at least 90%, at least 95%, or between 80 and 97%, between 80 and 99% by weight of the article (e.g. food package) consist of the material of the invention.Methods

[0099] In another aspect, there is provided a method of manufacturing the material of the invention, the method comprises contacting a cellulose-based material with the cationic polymer and the sizing agent and optionally the surface modifying agent in an aqueous medium, thereby obtaining a mixture;separating the mixture, to obtain a wet material and the aqueous medium; and drying the wet material, thereby obtaining the material of the invention.

[0100] In some embodiments, the cellulose-based material encompasses non-crosslinked and cellulose further devoid of chemical modification(s). In some embodiments, the cellulose-based material encompasses a material derived from processed or unprocessed plant biomass. In some embodiments, the cellulose-based material is a natural cellulose fiber-based material. In some embodiments, the cellulose-based material encompasses a raw cellulose based material (i.e. wherein the cellulose is substantially devoid of modified cellulose fibers). In some embodiments, the cellulose-based material is in a form of cellulose fibers disclosed hereinabove.

[0101] In some embodiments, the cellulose-based material is in a form of cellulose fibers disclosed hereinabove, and wherein the cellulose fibers are obtained by subjecting unprocessed cellulose fibers to milling or crushing, to obtain cellulose fibers characterized by an average length between 10 and 5000um, or between 20 and 3000um, including any range between.

[0102] In some embodiments, the method comprises simultaneously or subsequently contacting the cellulose-based material with the entire constituents of the mixture, such as the sizing agent, the cationic polymer and optionally the surface modifying agent and / or the colorant. In some embodiments, contacting comprises mixing or stirring.

[0103] In some embodiments, contacting comprises mixing a liquid composition comprising the cellulose-based material (in a form of cellulose fibers) with the cationic polymer and with the sizing agent, to obtain a mixture. In some embodiments, contacting further comprises adding any one of: the surface modifying agent, the colorant, and the acid or any combination thereof.

[0104] In some embodiments, the liquid composition is an aqueous composition comprising the cellulose-based material. In some embodiments, the mixture is an aqueous medium. In some embodiments, the aqueous medium is selected from water or an aqueous solution comprising water and one or more salts dissolved therewithin (e.g. an aqueous buffer). In some embodiments, aqueous medium is a liquid composition having water as the only solvent.

[0105] In some embodiments, the contacting step comprises providing the cellulose-based material dispersed in an aqueous medium, wherein a w / w concentration of the cellulose-based material in the aqueous medium is between 1 and 5%.

[0106] In some embodiments, the contacting step further comprises adding a sufficient amount of the cationic polymer, the sizing agent and optionally the surface modifying agent and / or the colorant to the aqueous medium, to obtain the mixture and further comprising mixing or stirring the resulting mixture. In some embodiments, mixing or stirring is performed for a time period ranging between Imin and lOh (or until completion of the contacting step, i.e. formation of a homogeneous mixture).

[0107] In some embodiments, the sufficient amount of the cationic polymer comprises a w / w ratio between the cellulose-based material and the cationic polymer within the mixture of between about 0.5 and 6%, between about 1 and about 10%, between about 1 and about 5%, between about 2 and about 10%, between about 3 and about 10%, between about 2 and about 5%, between about 3 and about 5%, between about 2 and about 6%, between about 1 and about 6%, including any range between.

[0108] In some embodiments, the sufficient amount of the sizing agent comprises a w / w portion of the sizing agent relative to the cellulose-based material within the mixture of betweenabout 0.5 and about 20%, between about 0.5 and about 1%, between about 0.5 and about 3%, between about 1 and about 2%, between about 1 and about 5%, between about 1 and about 3%, between about 1 and about 20%, about 1 and about 10%, between about 3 and about 10%, between about 3 and about 15%, between about 5 and about 10%, between about 3 and about 20%, between about 4 and about 10%, between about 4 and about 8%, between about 2 and about 8%, between about 4 and about 6%, between about 1 and about 6%, including any range between.

[0109] In some embodiments, the sufficient amount of the surface modifying agent comprises a w / w portion of the surface modifying agent relative to the cellulose-based material within the mixture of between about 0.5 and about 20%, between about 0.5 and about 1%, between about 0.5 and about 3%, between about 1 and about 2%, between about 1 and about 5%, between about 1 and about 3%, between about 1 and about 10%, between about 3 and about 10%, between about 3 and about 10%, between about 4 and about 10%, between about 4 and about 8%, between about 2 and about 8%, between about 4 and about 6%, between about 1 and about 6%, including any range between.

[0110] In some embodiments, the sufficient amount of the colorant (i.e. inorganic pigment) comprises a w / w ratio between the cellulose-based material and the colorant within the mixture of between about 0.5 and 5%, between about 1 and about 5%, between about 1 and about 3%, between about 2 and about 5%, between about 3 and about 5%, between about 0.5 and about 3%, between about 1 and about 4%, between about 0.5 and about 2%, between about 0.5 and about 3%, including any range between.

[0111] In some embodiments, the contacting step further comprising diluting the mixture with an additional amount of the aqueous medium, wherein the additional amount is sufficient for obtaining a w / w concentration of the cellulose-based material ranging between 0.2 and 1%, between 0.3 and 1%, between 0.2 and 0.5%, between 0.5 and 1%, between 0.6 and 1%, including any range between.

[0112] In some embodiments, the contacting step is performed under conditions comprising a temperature between 10 and 90°C, pH between 2 and 8, and a contacting time between lOmin and lOh.

[0113] In some embodiments, the separating step comprises separating the cellulose based material from the aqueous medium. In some embodiments, the separating is by sedimentation, centrifugation, filtration, or any combination thereof. In some embodiments, the separating step comprises separating the mixture from the aqueous medium to obtain the wet material in a formof cellulose fibers in contact with the cationic polymer, the surface modifying agent and optionally the sizing agent and / or the colorant, as disclosed above.

[0114] In some embodiments, the method further comprising washing the wet material after completion of the separating step. In some embodiments, washing is performed to remove the residual constituents (i.e. the sizing agent, the cationic polymer and optionally the surface modifying agent, the acid and / or the colorant) from the cellulose-based material.

[0115] In some embodiments, the separating step further comprises drying the wet material, to obtain a dried material. In some embodiments, the method further comprises shaping the wet material, to obtain a shaped article. In some embodiments, shaping and drying are performed simultaneously or subsequently. In some embodiments, shaping is performed by pressing (e.g. hot press), molding (e.g. compression molding), calendering, casting, vacuum forming, sheet forming, wet laid process, felting or any other shaping process applicable for cellulose fibers.

[0116] In some embodiments, there is provided a method for manufacturing the article of the invention, the method comprises providing a wet material comprising the cellulose fibers in contact with the cationic polymer, the surface modifying agent and optionally the sizing agent and / or the colorant, and subjecting the wet material under conditions suitable for shaping thereof, such as by pressing, molding (e.g. compression molding), calendaring, casting, vacuum forming, sheet forming, wet laid process, felting, or any other shaping process, thereby obtaining the article of the invention. In some embodiments, the wet material is obtained by the process disclosed herein.General

[0117] As used herein the term “about” refers to + / - 10 %.

[0118] The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to". The term “consisting of’ means “including and limited to”. Further, the term "comprises", "comprising", "includes", "including", “having” and their conjugates maybe alternatively used as “consisting”. For example the phrase “a composition comprises” also encompasses “a composition consists of’ or “a composition is”. As used herein, the term “comprises” including any grammatical form thereof may be used as “consisting essentially of’.

[0119] The term "consisting essentially of' means that the composition, method or structure may include additional ingredients, steps and / or parts, but only if the additional ingredients, steps and / or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. In some embodiments, “consists essentially of’ encompasses between 80and 100%, between 80 and 99%, between 90 and 99%, between 90 and 100%, between 92 and 99%, between 93 and 99%, between 95 and 99%, between 95 and 97% between 93 and 100%, between 95 and 100%, between 97 and 99%, between 97 and 100% by weight of the composition consists of the listed constituents and is devoid of additional ingredients which contribute to the essential properties of the composition, as disclosed herein.

[0120] The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments.

[0121] The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the invention may include a plurality of “optional” features unless such features conflict.

[0122] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

[0123] As used herein, the term “substantially” refers to at least 80%, at least 85%, at least 90%, at least 92%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, including any range or value therebetween.

[0124] Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0125] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging / ranges between” a first indicate number and a second indicate number and “ranging / ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

[0126] As used herein, the term "method" refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means,techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts.

[0127] As used herein, the term “treating” includes abrogating, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating clinical or aesthetical symptoms of a condition or substantially preventing the appearance of clinical or aesthetical symptoms of a condition.

[0128] As used herein, the term “prevention” of a disease, disorder, or condition encompasses the delay, prevention, suppression, or inhibition of the onset of a disease, disorder, or condition. As used in accordance with the presently described subject matter, the term "prevention" relates to a process of prophylaxis in which a subject is exposed to the presently described active ingredients prior to the induction or onset of the disease / disorder process. This could be done where an individual has a genetic pedigree indicating a predisposition toward occurrence of the disease / disorder to be prevented. For example, this might be true of an individual whose ancestors show a predisposition toward certain types of inflammatory disorders.

[0129] In those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description or claims, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

[0130] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub combination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0131] Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.EXAMPLESMaterials and methodsStandard procedure:

[0132] Cellulose based material (4% w / w in water) is crashed in a lab blender. The mixture is then stirred with a mechanical stirrer in a lab reactor. The reagents are then added according to the procedure. After all the reagents are reacted and mixed, the pulp mixture is diluted with water with stirring to 0.7-0.9% w / w cellulose fibers. Then a filtration of 450-700 cc of the mixture is carried out. The wet cake, after filtration, is then dried by hot press at 160-190°C. Pancakes of 3.0-5.0 gr are obtained.

[0133] The pancakes were tested for cobb oil and cobb water for half an hour to estimate the absorption of water and oil (g / m2) in the final pancakes. An oil drop test is carried out to observe the time it takes to the drop to penetrate to the other side.List of raw materials:

[0134] Cellulose based materials of bagasse, or hard wood or soft wood. PEI, Polyethylene imine (50% commercial grade, MW about 700 KDa), modified PEI- 1, Hexanedioic acid, polymer with N-(2-aminoethyl)- 1,3 -propanediamine, aziridine, (chloromethyl)oxirane, 1,2-ethanediamine, N,N"-l,2-et, (20% commercial grade), modified PEI-2, Hexanedioic acid, polymer with N-(2-aminoethyl)- 1,3 -propanediamine, aziridine, (chloromethyl)oxirane, 1,2-ethanediamine, N,N-l,2-ethanediylbisl,3-propanediamine, formic acid and . alpha. -hydro-. omega. -hydroxypoly (oxy- 1,2-ethanediyl), (20% commercial grade).

[0135] Phosphoric acid (85% food grade). Rosin based Emulsion (20% commercial grade). AKD emulsion (15-25% commercial grade). BA, butyl acrylate base emulsion (20-25% commercial grade). Aluminium oxide 99.7%. Silica, fumed 99%. CMC-Carboxymethyl Cellulose, sodium salt (Mw 250,000). Black colorant food grade El 72, red colorant food grade E172, red metal colorant food grade E172, bronze colorant food grade E172, metal copper colorant food grade El 72.EXAMPLE 1

[0136] The inventors tested water and oil repellency of the material of the invention, compared to control sample(s), according to Cobb and Oil drop test, as listed below. The results of these tests are summarized in Table 1.No. 1 (Control)

[0137] Reference: A bagasse mixture in water 4%, was stirred for 2 hours at room temperature. Then pancakes were made according to the standard procedure.Cobb water: 810 g / m2, Cobb oil: 145 g / m2Oil drop test: 10 min.No.2

[0138] To a stirred 4% bagasse mixture in water, The sizing agent, AKD, was added in an amount of 10% and stirred for 10 minutes. Pancakes were then made according to the standard procedure.Cobb water: 85 g / m2, Cobb oil: 110 g / m2Oil drop test: 15 min.No.3

[0139] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Pancakes were then made according to the standard procedure.Cobb water: 520 g / m2, Cobb oil: 125 g / m2Oil drop test: 15 min.No.4

[0140] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, BA, was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 95 g / m2, Cobb oil: 84 g / m2Oil drop test: 4 hr.No.5

[0141] To a stirred 4% bagasse mixture in water, 2.5% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then phosphoric acid was added in an amount of 1.5% (w / w Bagasse on dry basis) and stirred for 10 minutes. Then the sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 64 g / m2, Cobb oil: 62 g / m2Oil drop test: 4.5 hrNo.6

[0142] To a stirred 4% bagasse mixture in water, 2.5% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then phosphoric acid was added in anamount of 3% (w / w Bagasse on dry basis) and stirred for 10 minutes. Then the sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 170 g / m2, Cobb oil: 58 g / m2Oil drop test: 5 hrNo.7

[0143] To a stirred 4% bagasse mixture in water, 1% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 65 g / m2, Cobb oil: 40 g / m2Oil drop test: 24 hrNo.8

[0144] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 52 g / m2, Cobb oil: 54 g / m2Oil drop test: 24 hrNo. 9

[0145] To a stirred 4% soft wood fibers mixture in water, 0.5% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, was added in an amount of 3% and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 80 g / m2, Cobb oil: 185 g / m2Oil drop test: 10 min.No. 10

[0146] To a stirred 4% soft wood fibers mixture in water, 1% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 5% of Rosin emulsion (w / w Bagasse on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 33 g / m2, Cobb oil: 50 g / m2Oil drop test: >24 min.No.11

[0147] To a stirred 4% bagasse mixture in water, 2% modified PEI-1 (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, (w / w Bagasse on dry basis) was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 81 g / m2, Cobb oil: 81 g / m2Oil drop test: 4 hrNo.12

[0148] To a stirred 4% bagasse mixture in water, 6% modified PEI-2 (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 71 g / m2, Cobb oil: 70 g / m2Oil drop test: 4 hrNo.13

[0149] To a stirred 4% hardwood cellulose fibers mixture in water, 2% PEI (w / w fibers on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, was added in an amount of 10% (w / w fibers on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 52 g / m2, Cobb oil: 96 g / m2Oil drop test: >24 hrNo.14

[0150] To a stirred 4% softwood fibers mixture in water, 2% PEI (w / w fibers on dry basis) was added and stirred for 10 minutes at room temperature. Then the sizing agent, AKD, (w / w fibers on dry basis) was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure.Cobb water: 62 g / m2, Cobb oil: 88 g / m2Oil drop test: 24 hrNo.15

[0151] To a stirred 4% bagasse fibers mixture in water, 1.5% PEI (w / w fibers on dry basis) was added and stirred for 10 minutes at room temperature. Then 2% Aluminum oxide (w / w fibers on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, (w / w fibers on dry basis) was added in an amount of 10% and stirred for 10 minutes. Pancakes were then made according to the standard procedure.Cobb water: 68 g / m2, Cobb oil: 20 g / m2Oil drop test: >24 hrNo.16

[0152] To a stirred 4% bagasse fibers mixture in water, 1.5% PEI (w / w fibers on dry basis) was added and stirred for 10 minutes at room temperature. Then 2% silicon dioxide (w / w fibers on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, (w / w fibers on dry basis) was added in an amount of 10% and stirred for 10 minutes. Pancakes were then made according to the standard procedure.Cobb water: 71 g / m2, Cobb oil: 13 g / m2Oil drop test: >24 hrNo.17

[0153] To a stirred 4% bagasse fibers mixture in water, 1.5% PEI (w / w fibers on dry basis) was added and stirred for 10 minutes at room temperature. Then 0.75% CMC (w / w fibers on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, (w / w fibers on dry basis) was added in an amount of 10% and stirred for 10 minutes. Pancakes were then made according to the standard procedure.Cobb water: 66 g / m2, Cobb oil: 11 g / m2Oil drop test: >24 hrNo.18

[0154] To a stirred 4% bagasse fibers mixture in water, 1.5% PEI (w / w fibers on dry basis) was added and stirred for 10 minutes at room temperature. Then 0.75% sodium alginate (w / w fibers on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, (w / w fibers on dry basis) was added in an amount of 10% and stirred for 10 minutes. Pancakes were then made according to the standard procedure.Cobb water: 60 g / m2, Cobb oil: 30 g / m2Oil drop test: >24 hrAddition of colorants to obtain colored pancakesNo 19

[0155] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of black colorant E172 (w / w Bagasse on dry basis) was added and stirred for 10 minutes. Then the sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A grey colored pancake was obtained.Cobb water: 82 g / m2, Cobb oil: 83 g / m2Oil drop test: 4 hrNo 20

[0156] To a stirred 4% bagasse mixture in water, 1.5% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of black colorant E172 (w / w Bagasse on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A grey colored pancake was obtained.Cobb water: 58 g / m2, Cobb oil: 43 g / m2Oil drop test: >24 hrNo 21

[0157] To a stirred 4% bagasse mixture in water, 1% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of black colorant E172 (w / w Bagasse on dry basis) was added and stirred for 10 minutes. Rosin emulsion 5% (w / w Bagasse on dry basis) was then added and stirred for 10 minutes. Then the sizing agent, AKD emulsion, was added in an amount of 10% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A grey colored pancake was obtained. Cobb water: 40 g / m2, Cobb oil: 60 g / m2Oil drop test: >24 hrNo 22

[0158] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of red colorant El 72 (w / w Bagasse on dry basis) was added and stirred for 10 minutes. Then the sizing agent, AKD, was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A pink colored pancake was obtained.Cobb water: 52 g / m2, Cobb oil: 11 g / m2Oil drop test: >24 hrNo 23

[0159] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of red metal colorant El 72 (w / w Bagasse on dry basis), was added and stirred for 10 minutes. Then the sizing agent, AKD, was added in an amount of 10% and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A pink metal colored pancake was obtained.Cobb water: 62 g / m2, Cobb oil: 20 g / m2Oil drop test: >24 hrNo 24

[0160] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of bronze colorant E172 (w / w Bagasse on dry basis), was added and stirred for 10 minutes. Then the sizing agent, AKD emulsion, was added in an amount of 8% and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A light bronze colored pancake was obtained.Cobb water: 48 g / m2, Cobb oil: 30 g / m2Oil drop test: >24 hrNo 25

[0161] To a stirred 4% bagasse mixture in water, 2% PEI (w / w Bagasse on dry basis) was added and stirred for 10 minutes at room temperature. Then 1% of metal copper colorant E172 (w / w Bagasse on dry basis), was added and stirred for 10 minutes. Rosin emulsion 3% (w / w Bagasse on dry basis) was then added and stirred for 10 minutes. Then the sizing agent, AKD emulsion was added in an amount of 8% (w / w Bagasse on dry basis) and stirred for 15 minutes. Pancakes were then made according to the standard procedure. A light orange metal colored pancake was obtained.Cobb water: 48 g / m2, Cobb oil: 18 g / m2Oil drop test: >24 hrResults

[0162] Cellulose fibers have the property to absorb water and oil. In food packaging and other applications this property is undesired. Modification on the fibers is needed to achieve oil and water repellency of the fibers.

[0163] The inventors performed numerous trials to identify the suitable ingredients to be added to cellulose fibers to achieve improved water and oil repellency properties. The inventors also colored the composite cellulose fibers to achieve colored pancakes with improved water and oil repellency properties.

[0164] The inventors surprisingly observed that the addition of PEI to the cellulose fibers is essential for providing composite cellulose-based material with improved water and oil repellency properties. Further, addition of acid i.e phosphoric acid can react with the amine groups on the PEI to obtain ammonium groups. The ammonium groups can enhance the oil repellent properties.

[0165] Furthermore, the oil repellent property can be enhanced by addition of surface modifying agent such as Rosin. A sizing agent such as AKD, or emulsion based on Butyl acrylate, BA, further improves the water repellency of the modified cellulose fiber matrix. The sizing agent may be bound to the cellulose based material via intermol ecular interactions or covalent chemical bonds.

[0166] The treatment of the natural cellulose-based material (e.g. bagasse, soft wood or hard wood) according to the method disclosed herein drastically improves the water and oil repellency, as compared to the untreated natural cellulose-based material.

[0167] The absorption of water and oil into a modified cellulose fibers based matrix of the invention (also referred to herein as “pancakes”) was tested over 30 min by a cobb test measured by g / m2. An oil drop test was carried out to observe the time it takes to a drop of oil to penetrate and to pass to the other side. The results of the cobb test of oil and water and the drop test are summarized in Table 1.Table 1 : Cobb test of water and oil and drop test on colored pancakes>>>>>>>

[0168] From the results of Table 1 it is apparent that natural cellulose-based material without any treatment (Entry 1) absorbs water in very high levels and oil in high levels which penetrate and pass to the other side in a very short time.

[0169] Sizing agent AKD improves the water absorption dramatically. However, the oil penetrates very easily after 15 minutes to the other side.

[0170] Treatment of cellulose with cationic PEI alone (Entry 3) doesn’t affect much the water and oil absorption in compared to bagasse without additives. The addition of Cationic PEI and the Sizing agent BA (Entry 4) reduces the amount of absorbed water drastically and the oil absorption moderately.

[0171] The addition of Cationic PEI and the Sizing agent AKD (Entries 7-8) reduces the amount of absorbed water drastically and oil absorbed as well. However, in certain conditions (Entry 9) with low amount of PEI (0.5%) and low amount of AKD (3%) relative to the bagasse, the water repellency was improved in contrast to the oil repellency.

[0172] The addition of acid (e.g phosphoric acid entry 5) to the cationic PEI and to the sizing agent, can improve the water and oil repellent properties.

[0173] Addition of modifying agent to the cationic PEI and the sizing agent AKD (entry 10, 15-18) show improved results compared to PEI and AKD.

[0174] When chemically modified PEI was used with sizing agent AKD (Entries 11-12), it improves the water repellency and improved only moderately the oil repellency.

[0175] When other cellulose fibers rather than bagasse, i.e. cellulose fibers from hardwood and softwood (Entries 13-14), were tried, the performance shows improvement of the water and oil repellent properties compared to the control.

[0176] To thi s end, treating the natural cellulose-based material with cationic polymer PEI and using sizing agent provides to the natural cellulose-based material both water and oil repellent properties by obtaining a composite cellulose based material. Furthermore, addition of a surface modifying agent such as Rosin, fumed Silica, CMC and aluminium oxide, further improves of the water and oil repellent properties of the composite material.

[0177] Food grade colorants from the family of E172 (Iron oxide pigments) were used to achieve colored water and oil repellency pancakes. The modified cellulose fibers with the colorants improve the oil repellency properties. The results of the cobb test of oil and water and the drop test on colored pancakes are summarized in Table 2.Table 2: Cobb test of water and oil and drop test on colored pancakes.>>>>>>

[0178] Table 2 shows that the colored pancakes obtained are water and oil repellent. In general, all the colorants which were used with the cellulose composite materials show improved results in the cobb oil and water. The Cobb of water is improved from 810 g / m2(without any treatment) to less than 100 g / m2in the process described. The Cobb of oil is improved from 145 g / m2(without any treatment) to less than 100 g / m2in the process described.

[0179] The time for a drop of oil to penetrate to the other side was 10 minutes without treatment of the cellulose fibers, whereas after treatment over more than 4 hours and in some cases more than 24 hours.

[0180] The inventors postulate that the water and oil repellent cellulose fiber composites colored and uncolored disclosed herein can be utilized as a recyclable (and / or degradable / compostable) and environmentally friendly packaging material or dishware.

[0181] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

CLAIMSWhat is claimed is:

1. A material comprising cellulose fibers in contact with a cationic polymer and a sizing agent selected from alkyl ketene dimer (AKD), butyl acrylate, including any copolymer thereof, styrene acrylate co-polymer, alkenyl succinic anhydride, alkenyl succinic acid, including any combination and any salt thereof.

2. The material of claim 1, wherein an amount of said sizing agent within the material relative to the dry weight of the cellulose fibers is between 0.5 and 20%.

3. The material of claim 1 or 2, wherein the amount of said sizing agent is between 0.8 and 5%w / w and wherein said sizing agent is AKD.

4. The material of any one of claims 1 to 3, wherein the amount of said sizing agent is between 1 and 3%w / w.

5. The material of any one of claims 1 to 4, wherein the amount of said sizing agent is between 1 and 2%w / w.

6. The material of any one of claims 1 to 5, wherein a w / w portion of the cationic polymer relative to the dry weight of the cellulose fibers is between about 0.1 and about 10%.

7. The material of any one of claims 1 to 6, wherein the cellulose fibers comprise natural cellulose fibers derived from a plant biomass, and wherein between 80 and 100% w / w of the polymeric content of the plant biomass consists of cellulose, lignin or hemicellulose or any combination thereof.

8. The material of claim 7, wherein the plant biomass comprises any one of bagasse, wood biomass selected from softwood and hard wood, Eucalyptus biomass, bamboo biomass, coffee biomass, hemp biomass, grass biomass, wheat biomass, cotton biomass, Flax biomass, Jute biomass, Sisal biomass, Kenaf biomass, Rice straw biomass, Sorghum biomass, Banana stem biomass, Pineapple leaf biomass, Alfalfa biomass, or any combination thereof.

9. The material of any one of claims 1 to 8, wherein the cellulose fibers are in a form of a non-woven material coated by the cationic polymer and the sizing agent.

10. The material of any one of claims 1 to 9, wherein said cationic polymer is or comprises any one of polyethylene imine (PEI), poly(amidoamine dendrimer) (PAMAM) and Poly(dimethylamine ethyl methacrylate) (PDMAEME), including any mixture, and any co-polymer thereof.

11. The material of claim 10, wherein said PEI is selected from a branched and a linear PEI and is characterized by average MW of between 60.000 and 1.000.000 Da.

12. The material of claim 10 or 11, wherein said PEI is a non-modified PEI; and wherein a w / w portion of the non-modified PEI relative to the dry weight of the cellulose fibers is between about 0.1 and about 5%.

13. The material of any one of claims 1 to 12, further comprising a surface modifying agent;wherein the cellulose fibers, the surface modifying agent, the cationic polymer and the sizing agent are in a form of a composite material.

14. The material of claim 13, wherein at least one of: (i) a w / w portion of the surface modifying agent relative to the dry weight of the cellulose fibers is between about 1 and about 10%; and (ii) wherein the surface modifying agent selected from Polyvinyl alcohol (PVA), a non-cellulose polysaccharide, a cellulose derivative, a metal oxide particle, glycerin, abietic acid, melamine formaldehyde, urea formaldehyde and pinic acid, including any combination, any salt thereof.

15. The material of claim 14, wherein the metal oxide particle is selected from, zirconia, titania, alumina and silica, including any combination thereof.

16. The material of claim 14 or 15, wherein the non-cellulose polysaccharide is selected from starch, chitosan, guar gum, Xanthan gum, carrageenan, pectin, alginate, including any mixture, co-polymer and any salt thereof.

17. The material of any one of claims 14 to 16, wherein the cellulose derivative is selected from Carboxymethyl cellulose (CMC), Hydroxyethyl cellulose, and Methyl cellulose, including any mixture, co-polymer and any salt thereof.

18. The material of any one of claims 13 to 17, wherein the surface modifying agent is covalently bound to the cellulose fibers.

19. The material of any one of claims 1 to 18, further comprising a colorant.

20. The material of claim 19, wherein a w / w concentration of the colorant within the material is between 0.1 and 5% relative to the dry weight of the cellulose fibers; and wherein the colorant is an inorganic pigment.

21. The material of any one of claims 1 to 20, further comprising an acid and / or a salt thereof, wherein a w / w concentration of the acid within the material is between 0.1 and 5% relative to the dry weight of the cellulose fibers.

22. The material of claim any one of claims 1 to 21, wherein the cellulose fibers, the cationic polymer, the sizing agent, and optionally the surface modifying agent are uniformly distributed within the material.

23. The material of any one of claims 1 to 22, being an oil and water repellent material characterized by (i) water absorbency below 100 g / m2, as determined by Cobb test performed for 30min; and / or by (ii) oil absorbency below 90 g / m2, as determined by Cobb test performed for 30min.

24. The material of claim 23, wherein said material is characterized by oil absorption time of at least Ih, as determined by oil drop test.

25. An article comprising the material of any one of claims 1 to 24.

26. The article of claim 25, wherein said article is in a form of a ribbon, a sheet, a film, a packaging material, a thread, a container, or any combination thereof and wherein said article is shaped form the material.

27. The article of any one of claims 25 or 26, wherein said article is a food package or a dishware.

28. A method of manufacturing the material of any one of claims 1 to 17, comprising: mixing a cellulose-based material in an aqueous medium with (i) the cationic polymer and (ii) the sizing agent and optionally the surface modifying agent under suitable conditions, thereby obtaining a mixture;separating the mixture, to obtain a wet material; anddrying the wet material.

29. The method of claim 28, wherein a w / w concentration of the cellulose-based material in the aqueous medium in step i is between 1 and 5%.

30. The method of claim 28 or 29, wherein the step i further comprising diluting the mixture with an additional amount of the aqueous medium sufficient for obtaining a w / w concentration of the cellulose-based material ranging between 0.2 and 1%.

31. The method of any one of claims 28 to 30, wherein a w / w ratio between the cellulose- based material and the cationic polymer within said mixture is between about 0.5 and 6%; and wherein a w / w ratio between the cellulose-based material and (i) the surface modifying agent or (ii) the sizing agent within said mixture is between about 0.5 and about 10%.

32. The method of claim 31, wherein the w / w ratio between the cellulose-based material and (i) the surface modifying agent or (ii) the sizing agent within said mixture is between about 0.5 and about 3%.

33. The method of any one of claims 28 to 32, wherein said step i further comprises adding the colorant to said mixture and optionally at least one of the sizing agent and the acid.

34. The method of any one of claims 28 to 33, wherein the cellulose-based material is in a form of fibers characterized by an average length of between 10 and 5000um.

35. The method of any one of claims 28 to 34, wherein said separating is by filtration and wherein said process further comprising shaping the wet material; and wherein shaping and drying are performed simultaneously or subsequently.

36. The method of any one of claims 28 to 35, wherein said shaping comprises pressing, molding, calendaring, casting, vacuum forming, sheet forming, wet laid process, felting or any combination thereof.

37. The method of any one of claims 28 to 36, wherein said drying is performed by a hot press.

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