Oil and water repellent cellulose-based material and use thereof

Abstract

The present invention is directed to a cellulose based material comprising modified cellulose fibers, wherein the modified cellulose fibers are crosslinked via a covalent crosslinker; and are further covalently bound to a 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 THEREOFCROSS 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 / 537,580, filed on September 11, 2023, 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, wherein the cellulose fibers are crosslinked via a covalent crosslinker; and wherein the cellulose fibers are covalently bound to a surface modifying agent selected from Polyvinyl alcohol (PVA), abietic acid and pinic acid, including any combination, any salt, and any derivative thereof.

[0007] In one embodiment, a w / w portion of the covalent crosslinker relative to the dry weight of the cellulose fibers is between about 1 and about 10%.

[0008] In one embodiment, a w / w portion of the surface modifying agent relative to the dry weight of the cellulose fibers is between about 1 and about 20%.

[0009] In one embodiment, the cellulose fibers comprise natural cellulose fibers derived from a plant biomass.

[0010] In one embodiment, the plant biomass comprises bagasse.

[0011] In one embodiment, the plant biomass is pretreated or non-pretreated.

[0012] In one embodiment, the material is a non-woven material.

[0013] In one embodiment, bound is via a covalent bond.

[0014] In one embodiment, covalent crosslinker comprises any one of a poly-carboxylic acid, boric acid, sulfuric acid and phosphoric acid, including any salt or any combination thereof; optionally wherein the poly-carboxylic acid is selected from citric acid, malic acid, succinic acid, tartaric acid, malonic acid, glutaric acid and adipic acid, including any salt or any combination thereof.

[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, wherein the material is characterized by oil repellency and water repellency.

[0018] In one embodiment, water repellency comprises water absorbency below 100 g / m2, as determined by Cobb test performed for 30min; and wherein the oil repellency comprises oil absorbency below 90 g / m2, as determined by Cobb test performed for 30min.

[0019] In one embodiment, the material is characterized by oil absorption time of at least Ih, as determined by oil drop test.

[0020] In one embodiment, between 80 and 100% by total weight polymeric content of said material consists of cellulose, lignin and hemicellulose.

[0021] In another aspect, there is provided an article comprising the material of the invention.

[0022] 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.

[0023] In one embodiment, the article is a food package.

[0024] In another aspect, there is provided a method of manufacturing the material of the invention, comprising: contacting a cellulose-based material with (i) the covalent crosslinker and (ii) the surface modifying agent under suitable conditions, thereby obtaining a crosslinked cellulose-based material; applying the sizing agent to the crosslinked cellulose-based material, thereby obtaining the material.

[0025] In one embodiment, contacting the cellulose-based material with (i) and with (ii) is performed simultaneously or subsequently.

[0026] In one embodiment, contacting comprises mixing a liquid composition comprising the cellulose-based material with (i) and with (ii), to obtain a mixture.

[0027] In one embodiment, a w / w ratio between the cellulose-based material and the covalent crosslinker within the mixture is between about 1 and about 10%; 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%.

[0028] In one embodiment, the mixture further comprises a base in an amount sufficient to adjust a pH of the mixture to a pH value between 10 and 14.

[0029] In one embodiment, the liquid composition is an aqueous composition, and wherein the base is selected from an alkaline metal hydroxide, alkaline-earth metal hydroxide, and carbonate.

[0030] In one embodiment, the crosslinked cellulose-based material is covalently bound to the surface modifying agent.

[0031] In one embodiment, applying comprises adding the sizing agent at an amount ranging between 1 and 20% by weight of the cellulose-based material.

[0032] In one embodiment, the method further comprises isolating the material from the mixture to obtain an isolated material, and further comprising shaping the isolated material.

[0033] 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.

[0034] 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.

[0035] 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

[0036] In one aspect of the invention, there is provided a material comprising cellulose fibers, wherein the cellulose fibers are crosslinked via a crosslinker; and wherein the cellulose fibers are covalently bound to a surface modifying agent. In some embodiments, the material is a cellulose based material. In some embodiments, the material is a fibrous material. In some embodiments, the cellulose fibers of the invention are natural cellulose fibers crosslinked via the crosslinker, and wherein the natural cellulose fibers are modified by the surface modifying agent covalently bound thereto.

[0037] In another aspect of the invention, there is provided a material comprising a plurality of modified 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 plurality of modified cellulose fibers comprise or consist essentially of natural cellulose fibers covalently bound to (i) the crosslinker and (ii) to the modifying agent; and wherein a weight concentration and the chemical composition of (i) and (ii) within the material of the invention is as disclosed hereinbelow.

[0038] In some embodiments, the cellulose based material is a woven or a non-woven material. In some embodiments, the cellulose based material is a non-woven material. In some embodiments, the cellulose based material is derived from a natural material. In some embodiments, the natural material is a plant based material. In some embodiments, the natural material is a plant material, having 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.

[0039] The term “fiber” refers to individual strands of plant-based cellulose that is significantly longer than it is wide. 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).

[0040] 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 several millimeters (e.g. between 50um and 5mm, including any range between). Yams are usually divdied into 3 cathegories based on their diameter: Fine Y ams: 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); andThick 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).

[0041] In some embodiments, the cellulose fibers are derived from a natural material. In some embodiments, the natural material is 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.

[0042] In some embodiments, a polymeric content of the cellulose fibers derived from a natural material (i.e. total polymeric material of the cellulose fibers) 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.

[0043] 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 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.

[0044] 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.

[0045] 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.

[0046] Natural cellulose refers to cellulose that is derived directly from plant sources without undergoing significant chemical modification. It retains its original molecular structure and properties 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.

[0047] 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.

[0048] 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.

[0049] 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, 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.

[0050] In some embodiments, the material disclosed herein comprises natural cellulose fibers crosslinked via the crosslinker and modified via covalent bonding to the modifying agent. In some embodiments, the material disclosed herein is devoid of chemically modified cellulose fibers, comprising additional chemical modifications other than the chemical modifications disclosed herein (i.e. crosslinking and covalent bonding to the modifying agent disclosed herein). In some embodiments, the material disclosed herein consists essentially of natural cellulose fibers crosslinked via the crosslinker and modified via covalent bonding to the modifying agent disclosed herein. In some embodiments, the fibers of the material disclosed herein consist essentially of natural cellulose fibers crosslinked via the crosslinker and modified via covalent bonding to the modifying agent, disclosed herein. In some embodiments, the chemical modification (i.e. crosslinking and covalent bonding to the modifying agent) affects or is 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 (and further optionally of).

[0051] In some embodiments, the cellulose fiber content of the material of the invention is between 10 and 80%. In some embodiments, the cellulose content of the material of the invention is between 10 and 80%, between 50 and 80%, including any range between. In some embodiments, the material of the invention (i.e. not including the crosslinker and the surface modifying agent) consists essentially of cellulose, hemicellulose, and lignin.

[0052] In some embodiments, the cellulose fiber content from the total cellulose content of the material is between 80 and 100%, between 85 and 99%, between 90 and 100%, between 90 and 99%, between 95 and 99%, including any range between. In some embodiments, the material of the invention consists essentially of the modified cellulose fibers disclosed herein. In some embodiments, a weight content of the modified cellulose fibers within the material of the invention is between 80 and 100%, between 85 and 99%, between 90 and 100%, between 90 and 99%, between 95 and 99%, including any range between.

[0053] In some embodiments, the modified cellulose fibers consists essentially of cellulose, hemicellulose, and lignin, and further of the the crosslinker and the surface modifying agent.

[0054] In some embodiments, the crosslinker is a covalent crosslinker. In some embodiments, the crosslinker is a complexation crosslinker. In some embodiments, the crosslinker is a covalent crosslinker configured to crosslink cellulose molecules within the cellulose fibers. In some embodiments, the crosslinker is a covalent crosslinker configured to crosslink cellulose molecules via ester bond(s), phosphodiester bond(s), and / or sulfuric acid ester bond(s).

[0055] In some embodiments, the crosslinked cellulose fibers comprise (i) inter-crosslinks (i.e. crosslinks between 2 cellulose molecules located in adjacent fibers) and / or (ii) intra-crosslinks (i.e. crosslinks between 2 cellulose molecules located within the same fiber).

[0056] In some embodiments, the crosslinker is a bifunctional crosslinker, wherein each crosslinker molecule is configured to react with at least two hydroxy groups of cellulose. In some embodiments, the crosslinker comprises any one of a poly-carboxylic acid, boric acid, sulfuric acid and phosphoric acid, including any salt or any combination thereof. In some embodiments, the poly-carboxylic acid comprises a di-carboxylic acid, a tri-carboxylic acid or a tetra-carboxylic acid. In some embodiments, the poly-carboxylic acid comprises any one of: citric acid, malic acid, succinic acid, tartaric acid, malonic acid, glutaric acid and adipic acid, including any salt or any combination thereof. In some embodiments, the crosslinker is selected from citric acid, phosphoric acid and sulfuric acid, including any salt and any combination thereof.

[0057] In some embodiments, a w / w portion of the covalent crosslinker relative to the dry weight of the cellulose fibers within the material of the invention is 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.

[0058] 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 20%, is between about 1 and about 10%, between about 3 and about 10%, between about 3 andabout 15%, 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 15%, including any range between. In some embodiments, the surface modifying agent is 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 present in an amount of between 1 and 10% by weight, 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.

[0059] 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 surface modifying agent has a functional group capable of reacting with the crosslinker 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.

[0060] In some embodiments, the surface modifying agent is selected from Polyvinyl alcohol (PVA), glycerin, abietic acid and pinic acid, including any combination, any salt, and any derivative thereof. In some embodiments, the surface modifying agent comprises Rosin, (e.g. natural extract or at least partially purified or pre -treated natural Rosin). In some embodiments, the surface modifying agent comprises Polyvinyl alcohol (PVA) and glycerin.

[0061] In some embodiments, the material further comprises a sizing agent bound thereto. In some embodiments, the sizing agent is stably bound to the cellulose fibers.

[0062] 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).

[0063] In some embodiments, the sizing agent comprises any sizing agent known in the textile or paper industry. Various sizing agents are known in the art, such as surface sizing agent and 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.

[0064] In some embodiments, a w / w concentration of the sizing agent within the material is between 1 and 20%, between 1 and 10%, between 5 and 20%, between 5 and 10%, between 5 and 15%, including any range between.

[0065] 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 crosslinking agent is phosphoric acid present at a concentration between about 2-4% within the material; and wherein the sizing agent is present at a concentration between about 5-10% within the material, and optionally wherein the material further comprises trace amounts of Ca, or Na.

[0066] In some embodiments, the material of the invention is characterized by improved oil repellency and / or water repellency, as compared to a similar material solely treated by the sizing agent (i.e. devoid of cellulose crosslinking and devoid of cellulose modification by the surface modifying agent). In some embodiments, the material of the invention is characterized by improved oil repellency, as compared to a similar material solely treated by the sizing agent. 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).

[0067] In some embodiments, the material 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.

[0068] In some embodiments, the material 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.

[0069] In some embodiments, the material 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.

[0070] In another aspect, there is provided an article comprising the material of the invention. In some embodiments, the article comprises one or more layer(s), wherein at least one layer comprises the material of the invention.

[0071] 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.

[0072] 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.

[0073] In another aspect, there is provided a method of manufacturing the material of the invention, the method comprises contacting a cellulose-based material with (i) the crosslinker and (ii) the surface modifying agent under suitable conditions, thereby obtaining a crosslinked cellulose-based material; and applying the sizing agent to the crosslinked cellulose-based material, thereby obtaining the material. 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).

[0074] In some embodiments, the method comprises simultaneously or subsequently contacting the cellulose-based material with the crosslinker and with the surface modifying agent.

[0075] In some embodiments, contacting comprises mixing a liquid composition comprising the cellulose-based material with the crosslinker and with the surface modifying agent, to obtain a mixture. In some embodiments, the mixture further comprises a base in an amount sufficient to adjust a pH of the mixture to a pH value between 10 and 14. In some embodiments, the liquid composition is an aqueous composition comprising the cellulose-based material. In some embodiments, the mixture is an aqueous composition. In some embodiments, the aqueous composition is selected from water or an aqueous solution comprises a salt dissolved therewithin (e.g. a aqueous buffer). In some embodiments, the base is an inorganic base soluble in an aqueous composition. In some embodiments, the base is selected from an alkaline metal hydroxide (e.g. NaOH, LiOH, KOH), alkaline-earth metal hydroxide, and a bicarbonate / carbonate (e.g. Ca- bicarbonate, Ca-carbonate). In some embodiments, the contacting step comprises adding a sufficient amount of the crosslinker and with the surface modifying agent to an aqueous composition comprising the cellulose-based material, to obtain an aqueous mixture and further comprising mixing or stirring the resulting mixture. In some embodiments, mixing or stirring isperformed for a time period ranging between lOmin and lOh (or until completion of the contacting step).

[0076] In some embodiments, a w / w portion of the crosslinker relative to the cellulose-based material within the mixture is 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.

[0077] In some embodiments, a w / w portion of the surface modifying agent relative to the cellulose-based material within the mixture is between about 1 and about 20%, is between about 1 and about 10%, between about 3 and about 10%, between about 3 and about 15%, 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 15%, including any range between.

[0078] In some embodiments, the contacting step is performed under conditions suitable for (i) crosslinking the cellulose molecules within the cellulose-based material (e.g. via inert-crosslinks and / or via internal crosslinks), and (ii) covalently binding the surface modifying agent to the cellulose molecules within the cellulose-based material. Covalent bonding and / or crosslinking can be determined by FTIR, XRF.

[0079] In some embodiments, contacting step is performed under conditions comprising a temperature between 10 and 90°C, pH between 10 and 14, and a reaction time between lOmin and lOh.

[0080] In some embodiments, the method further comprising washing the cellulose-based material after completion of the contacting step. In some embodiments, washing is performed to remove the residual surface modifying agent and crosslinker from the cellulose-based material.

[0081] In some embodiments, the applying step comprises adding the sizing agent at an amount ranging between 1 and 20%, between 1 and 10%, between 5 and 20%, between 5 and 10%, between 5 and 15% by weight of the cellulose-based material, including any range between. In some embodiments, the applying step results in the sizing agent stably bound to the cellulose- based material (e.g. incorporated, embed, or absorbed to the cellulose-based material). In some embodiments, the method further comprising washing the cellulose-based material after completion of the applying step, to obtain a washed material.

[0082] In some embodiments, the method further comprising isolating the washed material (e.g. by removing the aqueous composition from the applying step or from the washing step, thereby obtaining an isolated material. In some embodiments, the isolating step further comprises a drying step, to obtain a dried material.

[0083] In some embodiments, there is provided a method for manufacturing the article of the invention, the method comprises providing the isolated material and subjecting the isolated material under conditions suitable for shaping thereof, such as by pressing, molding, or any other shaping process, thereby obtaining the material of the invention having a predetermined shape.General

[0084] As used herein the term “about” refers to ± 10 %.

[0085] 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”. 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 80 and 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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 forconvenience 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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 withinthe 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."

[0096] 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.

[0097] 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 methods

[0098] Standard procedure:

[0099] A cellulose fiber paper (4%) is crashed with water 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 to 0.7-0.9% w / w cellulose fibers. Then a filtration of 650-700 cc of the mixture is carried out. The wet cake after filtration is then dried by hot press at 150-170oC. Pancakes of 4.0-5.0 gr are obtained.

[0100] The pancakes were checked for cobb oil and cobb water for half an hour to estimate the absorption of water and oil (g / m2) in the final pancakes.

[0101] An oil drop test is carried out to observe the time it takes to the drop to penetrate to the other side.

[0102] List of raw materials:

[0103] Bagasse, Citric acid salt, sulfuric acid 62%, phosphoric acid 85%, Sodium hydroxide >96%, calcium carbonate >96%, calcium hydroxide, Polyvinyl alcohol (12% solution commercial grade), Rosin based Emulsion (commercial grade), AKD emulsion (commercial grade), BA, butyl acrylate base emulsion (26% commercial grade).EXAMPLE 1

[0104] The inventors tested water and oil repellency of the material of the invention, compared to numerous control samples, according to Cobb and Oil drop test, as listed below. The results of these tests are summarized in Table 1.No. 1

[0105] Reference: A bagasse mixture in water 4%, was stirred for 2 hours at room temperature. Then pancakes were made according to the standard procedure.

[0106] Cobb water: 810 g / m2, Cobb oil: 145 g / m2

[0107] Oil drop test: 10 min.No. 2

[0108] To a stirred 4% bagasse mixture in water, Sizing agent, BA (butyl acrylate), was added in an amount of 10% and stirred for 20 minutes. Pancakes were then made according to the standard procedure.

[0109] Cobb water: 85 g / m2, Cobb oil: 160 g / m2

[0110] Oil drop test: 10 min.No. 3

[0111] To a stirred 4% bagasse mixture in water, 3% sodium hydroxide (w / w Bagasse on dry basis) was added and stirred for 1 hour at room temperature. Then phosphoric acid 3% (w / w Bagasse on dry basis) was added and the mixture was stirred for additional 1 hour. Sizing agent, BA, was added in an amount of 10% and stirred for 50 minutes. Pancakes were then made according to the standard procedure.

[0112] Cobb water: 90 g / m2, Cobb oil: 100 g / m2

[0113] Oil drop test: 50 min.No. 4

[0114] To a stirred 4% bagasse mixture in water, 3.5% sodium hydroxide (w / w Bagasse on dry basis) was added and stirred for 10 min. Then 9% PVOH and Glycerin (w / w Bagasse on dry basis each) was added and stirred under heating to 50oC for 30 min. Then phosphoric acid 3% was added in at 50oC and the mixture was stirred for additional 45 min at 50oC. Sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis each). Pancakes were made then according to the standard procedure.

[0115] Cobb water: 80 g / m2, Cobb oil: 90 g / m2

[0116] Oil drop test: 2 hoursNo. 5

[0117] To a stirred 4% bagasse mixture in water, 3.9% sodium hydroxide (w / w Bagasse on dry basis) was added and stirred for 10 min. Then 6% PVOH (w / w Bagasse on dry basis each) was added and stirred at room temperature for 50 minutes. Then phosphoric acid 3.4% was added at room temperature and the mixture was stirred for additional 30 min. Sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis each) and stirred for 50 min. Pancakes were made then according to the standard procedure.

[0118] Cobb water: 86 g / m2, Cobb oil: 71 g / m2

[0119] Oil drop test: 90 minutes .No. 6

[0120] To a stirred 4% bagasse mixture in water, 3.9% calcium hydroxide (w / w Bagasse on dry basis) was added and stirred for 10 min. Then 6% PVOH (w / w Bagasse on dry basis each) was added and stirred at room temperature for 50 minutes. Then phosphoric acid 3.4% was added at room temperature and the mixture was stirred for additional 30 min. Sizing agent. BA, was added in an amount of 10% (w / w Bagasse on dry basis each) and stirred for 50 min. Pancakes were made then according to the standard procedure.

[0121] Cobb water: 86 g / m2, Cobb oil: 70 g / m2

[0122] Oil drop test: 90 minutes.No. 7

[0123] To a stirred 4% bagasse mixture in water, Rosin emulsion 10% (w / w Bagasse on dry basis each) was added and stirred at room temperature for 60 minutes. Sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis each) and stirred for 60 min. Pancakes were made then according to the standard procedure.

[0124] Cobb water: 75 g / m2, Cobb oil: 95 g / m2

[0125] Oil drop test: 70 min.No. 8

[0126] To a stirred 4% bagasse mixture in water, 2.8% sodium hydroxide (w / w Bagasse on dry basis) was added and stirred for 10 min. Then Rosin emulsion 10% (w / w Bagasse on dry basis each) was added and stirred at room temperature for 50 minutes. Then phosphoric acid 2.8%was added at room temperature and the mixture was stirred for additional 30 min. Sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis each) and stirred for 30 min. Pancakes were made then according to the standard procedure.

[0127] Cobb water: 85 g / m2, Cobb oil: 86 g / m2

[0128] Oil drop test: 3.5 hours.No. 9

[0129] To a stirred 4% bagasse mixture in water, 2.8% calcium hydroxide (w / w Bagasse on dry basis) was added and stirred for 20 min. Then Rosin emulsion 3.5% (w / w Bagasse on dry basis each) was added and stirred at room temperature for 50 minutes. Then sulfuric acid 3.8% was added at room temperature and the mixture was stirred for additional 30 min. Sizing agent, BA, was added in an amount of 10% (w / w Bagasse on dry basis each) and stirred for 30 min. Pancakes were made then according to the standard procedure.

[0130] Cobb water: 88 g / m2, Cobb oil: 65 g / m2

[0131] Oil drop test: 2.5 hours .No. 10

[0132] To a stirred 4% bagasse mixture in water, 3.3% sodium hydroxide (w / w Bagasse on dry basis) was added and stirred for 20 min. Then Rosin emulsion 5% (w / w Bagasse on dry basis each) was added and stirred at room temperature for 50 minutes. Then phosphoric acid 3.8% was added at room temperature and the mixture was stirred for additional 30 min. Sizing agent, AKD, was added in an amount of 5% (w / w Bagasse on dry basis each) and stirred for 30 min. Pancakes were made then according to the standard procedure.

[0133] Cobb water: 85 g / m2, Cobb oil: 55 g / m2

[0134] Oil drop test: 4.5 hours.

[0135] Cellulose fibers have the property to absorb water and oil. In food packaging and other applications this property is undesired. Modification or cross-linking reactions on the fibers is needed to achieve oil and water repellency of the fibers.

[0136] The inventors performed crosslinking of cellulose fibers by esterification reaction between the hydroxyl groups of the fibers and bi- tri- or more functional acids. The fibers are activated with base to catalyze the crosslinking reaction. The crosslinking reaction between the cellulose fibers improves the oil repellency property.

[0137] Enhancement of the oil repellent property is enhanced by addition of surface modifying agent, such as PVOH or Rosin during or after the process of crosslinking.

[0138] A sizing agent such as AKD, or emulsion based on Butyl acrylate, BA, further improves the water repellency. The sizing agent may be bound to the cellulose based material via hydrophobic interactions or chemical bonds.

[0139] The treatment of the natural cellulose-based material (e.g. bagasse) according to the method disclosed herein drastically improves the water and oil repellency, as compared to the untreated natural cellulose-based material.

[0140] The absorption of water and oil into a shaped material 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.

[0141] Table 1: Cobb test of water and oil and drop test on pancakes.

[0142] From the results of Table 1 it is apparent that natural cellulose-based material without any treatment absorb water in very high levels (Exp 1) and oil in high level which penetrate and pass to the other side in a very short time. The addition of Sizing agent (Entry 2) reduces the amount of absorbed water drastically; however, the oil absorption is still high, and the time for the drop to penetrate to the other side is very short.

[0143] Esterification of the cellulose fibers by phosphoric acid with a base catalyzation as well as treatment with sizing agent reduces the water and oil absorption from the modified fibers. However, oil repellency of the natural cellulose-based material solely treated with the sizing agent along with (i) crosslinker or (ii) surface modifier is still insufficient, as demonstrated by oil drop test (#3 and 7).

[0144] Entries 4-6 were carried out in the presence of PVOH as the surface modifying agent. The inventors postulate that PVOH undergoes covalent attachment to the cellulose fibers via ester bonds.

[0145] From the results in Table 1 it is apparent that the drop test results were improved in all of these experiments in comparison to experiments that were done without PVOH (#3).

[0146] Entries 7-10 were carried out in the presence of Rosin emulsion as the surface modifying agent. The main ingredient in the Rosin is abietic acid. The inventors postulate that abietic can undergoes covalent attachment to the cellulose fibers via ester bonds.

[0147] Entry 7 shows the results for treatment of the natural cellulose-based material with Rosin along with a sizing agent. The drop test show that the oil penetrates during about one hour. However, treating the natural cellulose-based material with acid and base together with Rosin followed by a sizing agent treatment, dramatically improved the time for repellency of the oil drop (# 8-10).

[0148] From Table 1 it can be concluded that treating the natural cellulose-based material with (i) a multi-functional acid (as a crosslinker), and (ii) a surface modifying agent such as PVOH or Rosin at a basic pH, followed by treatment with a sizing agent provides to the natural cellulose-based material both water and oil repellent properties. The inventors postulate, that the water and oil repellent material disclosed herein can be utilized as a recyclable (and / or degradable / compostable) and environmentally friendly packaging material.

[0149] 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, wherein the cellulose fibers are crosslinked via a covalent crosslinker; and wherein said cellulose fibers are covalently bound to a surface modifying agent selected from Polyvinyl alcohol (PVA), abietic acid and pinic acid, including any combination, any salt, and any derivative thereof.

2. The material of claim 1, wherein a w / w portion of the covalent crosslinker relative to the dry weight of the cellulose fibers is between about 1 and about 10%.

3. The material of claim 1 or 2, 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 20%.

4. The material of any one of claims 1 to 3, wherein the cellulose fibers comprise natural cellulose fibers derived from a plant biomass.

5. The material of claim 4, wherein the plant biomass comprises bagasse.

6. The material of claim 4 or 5, wherein the plant biomass is pretreated or non-pretreated.

7. The material of any one of claims 1 to 6, wherein the material is a non-woven material.

8. The material of any one of claims 1 to 7, wherein said bound is via a covalent bond.

9. The material of any one of claims 1 to 8, wherein said covalent crosslinker comprises any one of a poly-carboxylic acid, boric acid, sulfuric acid and phosphoric acid, including any salt or any combination thereof; optionally wherein the poly-carboxylic acid is selected from citric acid, malic acid, succinic acid, tartaric acid, malonic acid, glutaric acid and adipic acid, including any salt or any combination thereof.

10. The material of any one of claims 1 to 9, further comprising a sizing agent in an amount ranging between 1 and 20% relative to the dry weight of the cellulose fibers.

11. The material of any one of claims 1 to 10, wherein said 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.

12. The material of any one of claims 1 to 11, wherein said material is characterized by oil repellency and water repellency.

13. The material of claim 12, wherein said water repellency comprises water absorbency below 100 g / m2, as determined by Cobb test performed for 30min; and wherein said oil repellency comprises oil absorbency below 90 g / m2, as determined by Cobb test performed for 30min.

14. The material of claim 13, wherein said material is characterized by oil absorption time of at least Ih, as determined by oil drop test.

15. An article comprising the material of any one of claims 1 to 14.

16. The article of claim 15, 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.

17. The article of any one of claims 15 or 16, wherein said article is a food package.

18. A method of manufacturing the material of any one of claims 1 to 14, comprising: contacting a cellulose-based material with (i) the covalent crosslinker and (ii) the surface modifying agent under suitable conditions, thereby obtaining a crosslinked cellulose-based material; applying the sizing agent to said crosslinked cellulose-based material, thereby obtaining said material.

19. The method of claim 18, wherein contacting the cellulose-based material with (i) and with (ii) is performed simultaneously or subsequently.

20. The method of claim 18 or 19, wherein said contacting comprises mixing a liquid composition comprising the cellulose-based material with (i) and with (ii), to obtain a mixture.

21. The method of claim 20, wherein a w / w ratio between the cellulose-based material and the covalent crosslinker within said mixture is between about 1 and about 10%; and wherein a w / w ratio between the cellulose-based material and the surface modifying agent within said mixture is between about 1 and about 10%.

22. The method of claim 20 or 21, wherein said mixture further comprises a base in an amount sufficient to adjust a pH of said mixture to a pH value between 10 and 14.

23. The method of claim 22, wherein said liquid composition is an aqueous composition, and wherein said base is selected from an alkaline metal hydroxide, alkaline-earth metal hydroxide, and carbonate.

24. The method of any one of claims 18 to 23, wherein said crosslinked cellulose-based material is covalently bound to the surface modifying agent.

25. The method of any one of claims 18 to 24, wherein applying comprises adding the sizing agent at an amount ranging between 1 and 20% by weight of the cellulose-based material.

26. The method of any one of claims 18 to 25, further comprising isolating said material from said mixture to obtain an isolated material, and further comprising shaping the isolated material.

27. The material of any one of claims 1 to 14, wherein between 80 and 100% by total weight polymeric content of said material consists of cellulose, lignin and hemicellulose.

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