Repulpable barrier packaging

Abstract

A cellulosic, fiber-based material having moisture barrier properties is shown and described herein. The cellulosic, fiber-based material, which may be referred to as a paper barrier material, is repulpable providing a material that exhibits moisture barrier properties to provide products with extended ambient shelf life and provides high yields during recycling processes. The material can be employed as a moisture barrier material suitable for use in packaging materials. Also shown and described are barrier materials and articles comprising the paper barrier material.

Description

PATENT APPLICATIONDocket No.: 55334-00019REPULP ABLE BARRIER PACKAGINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 681,217, titled ‘ REPULPABLE BARRIER PACKAGING,” filed on August 9, 2024, the disclosure of which is incorporated herein by reference in its entirety.FIELD OF INVENTION

[0002] The present technology relates to a barrier packaging material, packaging materials comprising the same, and articles comprising the same. In particular, the present technology relates to a repulpable paper-based barrier material having water vapor barrier properties. The paper-based barrier material may be used in packaging and is suitable for packaging material and articles for housing foodstuffs or other products where the control of the ingress or egress of moisture in the package is desirable.BACKGROUND

[0003] Utilizing cellulosic, fiber-based materials, like paper or paperboard, presents a challenge in maintaining product freshness over time as cellulosic, as such materials do not exhibit or possess significant moisture barrier properties. Traditionally, these products have employed plastic membrane layers to create barriers against moisture. Barriers are typically established by applying a coating to the fiber-based substrate to impart it with barrier properties. Various coatings can be employed based on the required barrier characteristics. Common materials used for forming barriers on fiber-based products include polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), ethylene vinyl alcohol (EV OH), or ethylene vinyl acetate (EVA). However, achieving the necessary thickness of a polymer layer to provide effective barrier properties can be costly.

[0004] Laminated paper materials do find wide application in packaging for various products, including, for example, food items (liquids, solids, hot or cold), ream wrap,136634300.1sandwich wrap, and numerous other uses. Their extensive usage and subsequent disposal, however, raises concerns regarding their biodegradability in landfills and other waste disposal sites. The combination of plastic with cellulosic fibers often renders the packaging non- recyclable within paper recycling systems. Packaging materials comprising multiple layers of polyolefins pose challenges in the repulping process because of difficulties in separating the plastic coating from the paperboard.

[0005] Limiting the content and type of polymers used in the moisture barrier layers has been proposed as a way to render the structures recyclable and repulpable. U.S. Patent Publication US2023 / 365283 discloses a cellulosic fiber-based material with at least one moisture barrier layer attached to the substrate. The moisture barrier layer comprises a polyolefin-based polymer resin, a functionalized polyolefin-based polymer resin, and a dried polymer dispersion. The combined weight of the polymer materials in the multilayer packaging material does not exceed 20% by weight of the total weight. In this manner, the quantity' of non-cellulosic materials in the structures can be reduced to sufficiently low levels to render the structures recyclable and repulpable.

[0006] U.S. Patent No. 8.637,126 discloses a paper-based substrate having one or more layers of biodegradable / compostable polymers that have oxygen and moisture barrier properties. An example of a degradable described in the ‘126 patent is a polyolefin (dPE) blended with a transition metal carboxylate catalyst. If the barrier layers have poor adhesion, degradable tie layers can be included to improve adhesion. However, such restrictions in the content and type of polymers limits the barrier performance and material selection for optimization.

[0007] U.S. Patent No. 6,150,451 describes a composition designed to create a repulpable moisture vapor barrier coating for flexible packaging materials. This composition includes a wax-free polymer emulsion and a particulate material additive consisting of carboxylated styrene-butadiene. This additive has the ability to combine within the interstices of the polymer particles and forms a coating on the flexible packaging material, thereby maintaining the moisture vapor barrier properties imparted by the polymer. During the repulping process the additive helps breakdown the polymer layer and avoid common problems during the fiber recovery process, such as plugging the screen or contaminating the finished product. The barrier performance, however, is dependent on the polymer content and the coating layer thickness and limited by the ability7to breakdown the coating to sufficiently smaller particles during repulping process.236634300.1

[0008] In practice, it is still difficult to achieve the perfect balance between barrier performance and ability to repulp the packaging material with prior methods and package designs such as those described above.SUMMARY

[0009] The following presents a summary of this disclosure to provide a basic understanding of some aspects. This summary is intended to neither identify key or critical elements nor define any limitations of embodiments or claims. Furthermore, this summary may provide a simplified overview of some aspects that may be described in greater detail in other portions of this disclosure.

[0010] In one aspect, provided is a cellulosic, fiber-based material having moisture barrier properties. The present cellulosic, fiber-based material is repulpable providing a material that exhibits moisture barrier properties to provide products with extended ambient shelf life and provides high yields during recycling processes.

[0011] In another aspect, provided is a packaging material comprising the paper barrier material. In one embodiment, the paper barrier material may be used to form a packaging material.

[0012] In another embodiment, the paper barrier material constitutes a layer of a packaging material. In still another embodiment, the packaging material may comprise two or more layers formed from the paper barrier material. In one embodiment, the packaging material comprises at least one moisture barrier layer adjacent to a layer formed from the paper barrier material.

[0013] In another aspect, provided is an article comprising the packaging material that comprises the paper barrier material. The article may be formed from the packaging material or the packaging material may constitute a component (e.g., a lid or cover) of the article. The article is configured to house or store a product, and is particularly suited for use with products where it is desirable that a article moisture content be maintained within the article such as to, for example, maintain the integrity of the product stored therein.

[0014] In one aspect, provided is a packaging material comprising a substrate having a first surface and a second surface opposite the first surface, the substrate layer comprising (i) a bulk layer of paper defining a plurality of cavities, and (ii) a filler particle that sorbs water, wherein at least one of the plurality of cavities has at least one filler particle in communication therewith.

[0015] In one embodiment, the filler particle comprises surface hydroxyl groups.336634300.1

[0016] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle is selected from silica, anhydrous salts, molecular sieves, silica gels, clays, starches, ammonium chloride, calcium chloride, calcium carbonate, calcium oxide, potassium chloride, potassium carbonate, sodium chloride, sodium phosphate di-basic, sodium pyrophosphate, sodium nitrate, or a combination of two or more thereof.

[0017] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle is selected from silica.

[0018] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle has an average particle size of from about 1 nm to about 150 nm.

[0019] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle has a surface area of from about 50 m2 / g to about 600 m2 / g..

[0020] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle is present in the substrate in an amount of from about 0.1 wt.% to about 12 wt.% based on the weight of the substrate.

[0021] In one embodiment in accordance with any of the previous aspects or embodiments, the substrate further comprises a nanocellulosic material. In one embodiment, the nanocellulosic material is selected from microfibrillated cellulose.

[0022] In one embodiment in accordance with any of the previous aspects or embodiments, the nanocellulosic material is comprises the nanocellulosic material in an amount of from about 2 wt.% to about 10 wt.% based on the weight of the substrate.

[0023] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging material further comprises a hydrophobic sizing agent. In one embodiment, the hydrophobic sizing agent is disposed within the substrate.

[0024] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging material comprises a moisture barrier coating disposed on the first surface of the substrate, the second surface of the substrate, or both the first and second surface of the substrate.

[0025] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging material comprises a moisture barrier coating disposed on the first surface of the substrate.

[0026] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging material comprises a sealing layer disposed on the second surface of the substrate.436634300.1

[0027] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging material comprises a moisture barrier coating disposed on the second surface of the substrate.

[0028] In another aspect, provided is a package defining an interior space for holding a product, the package comprising the packaging material of any of the previous aspects or embodiments.

[0029] In one embodiment, the package comprises a first package wall and a second package wall, wherein the interior space is defined between the first and second package wall, and the first and second package walls are formed from the packaging material of the previous aspects or embodiments.

[0030] In one embodiment, the package comprises a container portion defining an interior space, and a cover disposed over the container portion, wherein the cover comprises the packaging material of the previous aspects or embodiments.

[0031] In still another aspect, provided is a packaging material comprising a first outer layer; a second outer layer; an inner layer disposed between the first outer layer and the second outer layer; a first paper barrier layer disposed between the first outer layer and the inner layer; and a second paper barrier layer disposed between the second outer layer and the inner layer; the first and second paper barrier layers independently comprising (i) a bulk layer of paper defining a plurality of cavities, and (ii) a filler particle that sorbs water, wherein at least one of the plurality’ of cavities has at least one filler particle in communication therewith.

[0032] In one embodiment, the first outer layer, the second outer layer, and the inner layer are substantially free of nanofiller particles.

[0033] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle comprises surface hydroxyl groups.

[0034] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle is selected from silica, anhydrous salts, molecular sieves, silica gels, clays, starches, ammonium chloride, calcium chloride, calcium carbonate, calcium oxide, potassium chloride, potassium carbonate, sodium chloride, sodium phosphate di-basic, sodium pyrophosphate, sodium nitrate, or a combination of two or more thereof.

[0035] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle is selected from silica.536634300.1

[0036] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle has an average particle size of from about 1 nm to about 150 nm.

[0037] In one embodiment in accordance with any of the previous aspects or embodiments, the filler particle has a surface area of from about 50 m2 / g to about 600 m2 / g.

[0038] In one embodiment in accordance with any of the previous aspects or embodiments, the first and second paper barrier layers independently comprise the filler particle in in an amount of from about 0.1 wt.% to about 12 wt.% based on the weight of the substrate.

[0039] In one embodiment in accordance with any of the previous aspects or embodiments, the first and second paper barrier layers independently comprise further comprises a nanocellulosic material. In one embodiment, the nanocellulosic material is selected from microfibrillated cellulose.

[0040] In one embodiment in accordance with any of the previous aspects or embodiments, the nanocellulosic material is comprises the nanocellulosic material in an amount of from about 2 wt.% to about 10 wt.% based on the weight of the substrate.

[0041] In one embodiment in accordance with any of the previous aspects or embodiments, the packaging material comprises a hydrophobic sizing agent. In one emodiment, the hydrophobic sizing agent is disposed within the first and second paper barrier layers.

[0042] In one embodiment in accordance with any of the previous aspects or embodiments, the inner layer has a thickness that is from about 20% to about 60% of a total thickness of the packaging material.

[0043] In one embodiment in accordance with any of the previous aspects or embodiments, the inner layer has a thickness that is from about 30% to about 50% of a total thickness of the packaging material.

[0044] In yet another aspect, provided is an article comprising the packaging material in accordance with any of the previous aspects or embodiments

[0045] The following description and the drawings disclose various illustrative aspects. Some improvements and novel aspects may be expressly identified, while others may be apparent from the description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS636634300.1

[0046] The accompanying drawings illustrate various systems, apparatuses, devices and related methods, in which like reference characters refer to like parts throughout, and in which:

[0047] FIG. 1 is a schematic sectional view of a moisture barrier material comprising a paper barrier material;

[0048] FIG. 2 is a schematic sectional view of an embodiment of a multilayer moisture barrier material;

[0049] FIG. 3 is a schematic sectional view of an embodiment of a multilayer moisture barrier material;

[0050] FIG. 4 is a schematic sectional view of an embodiment of a multilayer moisture barrier material;

[0051] FIG. 5 is a schematic sectional view of an embodiment of a multilayer moisture barrier material; and

[0052] FIG. 6 is a schematic sectional view of an embodiment of a multilayer moisture barrier material.DETAILED DESCRIPTION

[0053] Reference will now be made to exemplary embodiments, examples of which are illustrated in the accompanying drawings. It is to be understood that other embodiments may be utilized and structural and functional changes may be made. Moreover, features of the various embodiments may be combined or altered. As such, the following description is presented by way of illustration only and should not limit in any way the various alternatives and modifications that may be made to the illustrated embodiments. In this disclosure, numerous specific details provide a thorough understanding of the subject disclosure. It should be understood that aspects of this disclosure may be practiced with other embodiments not necessarily including all aspects described herein, etc.

[0054] As used herein, the words “example” and “exemplary” means an instance, or illustration. The words “example” or “exemplary ” do not indicate a key or preferred aspect or embodiment. The word “or” is intended to be inclusive rather than exclusive, unless context suggests otherwise. As an example, the phrase “A employs B or C,” includes any inclusive permutation (e.g., A employs B; A employs C; or A employs both B and C). As another matter, the articles “a” and “an” are generally intended to mean “one or more” unless context suggest otherwise.736634300.1

[0055] The recitation of numerical ranges includes all numbers (whole numbers, fractions, or decimals) subsumed within that range. Numerical ranges for a given parameter may be combined to form new and non-specified ranges.

[0056] Provided is, among other things, a repulpable paper barrier material possessing outstanding water vapor barrier properties, a repulpable barrier material composition, packaging materials comprising the repulpable barrier material, and articles comprising the repulpable barrier material configured to house products such as. for example, foodstuffs that are disposed within packages. The repulpable paper barrier material may also be referred to herein as the repulpable barrier material and / or the paper barrier material. In embodiments, the repulpable paper barrier material comprises a base paper composition, and a nanoparticle filler. The paper barrier material may optionally comprise one or more of a hydrophobic sizing additive and / or a nanocellulose additive. In some embodiments, the repulpable paper barrier material further comprises at least one moisture barrier coating layer. In some embodiments described herein, the repulpable barrier material is free of any other polymer coatings or a laminated polymer layer or a metal layer yet still serves to maintain a desired range of moisture content within a sealed package that includes the repulpable barner material.

[0057] As used herein, “recyclable” refers to a paper-based product that is acceptable into a paper recycling program. As used herein, “repulpable” refers to a product that can be reused or remade into paper.

[0058] Paper substrate

[0059] The paper barrier material comprises a paper substrate. The paper substrate is formed from a pulp comprising a plurality of fibers. The pulp is selected from a material that is repulpable. Examples of suitable pulp material includes, but is not limited to, pulps from wood, flax, hemp, sisal, aback, and the like. Examples of wood pulp include, but are not limited to, pulp from spruce, pine, larch, beech, birch, eucalyptus, and the like.

[0060] The pulp material can be formed into paper sheets by any suitable method as is now known or later discovered. As described further herein, the process may include providing a nano particle filler and one or more other additives to impart moisture barrier properties to the paper.

[0061] The weight of the paper is not particularly limited and can be selected for a particular application or intended use.

[0062] Nano Particle Fillers836634300.1

[0063] The paper barrier material comprises a nanoparticle filler material. The nanoparticle filler is selected from a material that sorbs water or reacts with water via chemical reaction (e.g., hydration) to form a new compound. As used herein, ‘'sorb” refers to a material that can absorb, adsorb, or both absorb and adsorb water. In embodiments, the repulpable barrier material includes a nano particle filler that sorbs water via physisorption or a nano particle filler that, upon reaction with water, sorbs water via physisorption.

[0064] Examples of suitable nano particle fillers that sorbs water via physisorption or a nano particle filler that, upon reaction with water, sorbs water via physisorption, one or more of which can be included in the repulpable barrier material, include anhydrous salts, molecular sieves, silica gels, clays, starches, ammonium chloride, calcium chloride, calcium carbonate, calcium oxide, potassium chloride, potassium carbonate, sodium chloride, sodium phosphate di-basic, sodium pyrophosphate, and sodium nitrate. Some preferred examples of suitable nano particle fillers include silica such as fumed silica or amorphous silica, silicates, zeolites, clays, activated carbon, calcium chlorite, calcium carbonate, absorbent polymers, and the like. In embodiments, the nanoparticle fillers comprise a surface functionality configured to interact with water molecules. In one embodiment, the nanoparticle filler comprises surface hydroxyl groups.

[0065] The nanoparticle filler can have an average particle size of from about 1 nm to about 250 nm, from about 5 nm to about 200 nm, from about 10 nm to about 175 nm, from about 20 nm to about 150 nm, from about 25 nm to about 125 nm, from about 30 nm to about 100 nm, from about 40 nm to about 75 nm, or from about 50 nm to about 60 nm.

[0066] In some embodiments, the nano filler particles are selected based on their specific surface area. Without wishing to be bound by any particular theory, nano filler particles with higher specific surface area are more effective in providing barrier performance. The higher surface area increases the water sorbing capacity and is expected to result in a higher vapor pressure inside the cavity that is in communication with the nano filler particle. The higher vapor pressure results in higher barrier to moisture transmission through the cavity. In one embodiment, the nano filler particle has a specific surface area of from about 50 m2 / g to about 600 m2 / g. from about 100 m2 / g to about 500 m2 / g, from about 150 m2 / g to about 450 m2 / g, or from about 200 m2 / g to about 400 m2 / g.

[0067] In one embodiment, the paper barrier material comprises silica. Silica surfaces can form hydrogen bonds with water molecules through silanol groups, which are Si-OH groups. The type of silanol group and its acidity can affect the strength of the hydrogen bond. In-plane silanols have an acid dissociation constant (pKa) of 8.5 and form weaker hydrogen936634300.1bonds. Out-of-plane silanols have a strong acidic character (pKa = 5.6) and form strong, short hydrogen bonds with water molecules. Without being bound to any particular theory’, the stronger hydrogen bonds between the silanol group and water has been found to provide a level of repellency for additional water molecules in the immediate vicinity of the silica surface.

[0068] Nano silica, or silicon dioxide nanoparticles, refers to extremely small particles of silica with dimensions typically ranging from 1 to 100 nanometers. Nano silica exhibits effectiveness in absorbing water vapor and other aqueous substances due to its fine porosity7, which results in a large surface area for trapping moisture. These nano silica particles remove moisture by adsorbing it onto the surface of their pores, rather than absorbing it into the particles themselves. Its moisture-adsorbing capabilities enable the nano silica particles to control the humidity and related vapor pressure in immediate vicinity of the particles.

[0069] In one embodiment, the nanoparticle filler is selected from fumed silica. In one embodiment, the fumed silica has a primary particle size of from about 5 to about 50 nm. These primary particles are non-porous. and the agglomerated secondary particles formed in solution typically have a surface area of 50-600 m2 / g. Suitable fumed silica include, but are not limited to, available from Evonik Degussa, Cabot, and Wacker Chemie-Dow Coming. An example of suitable fumed silica is Evonik Aerosil 380, having an average particle size of between 1 and 50 nanometers, such as about 5 nanometers, about 7 nanometers, about 12 nanometers, or about 50 nanometers.

[0070] The repulpable barrier material may comprise from about 0. 1 wt.% to about 12 wt.%, from about 0.5 wt.% to about 10 wt.%, from about 1 wt.% to about 8 wt.%, or from about 3 wt.% to about 6 wt.% of the nanoparticle fillers based on the total weight of the paper material layer in which the nanoparticle filler is contained. Thus, in a barrier material comprising a plurality of paper barrier layers, each paper barrier layer may’ separately contain the nanoparticle filler in the amounts described. In embodiments, the repulpable barrier material may include from about 3 wt.% to about 12 wt.% of the nanoparticle filler. In still other embodiments, the repulpable barrier material may include from about 6 wt.% to about 10 wt.% of the nanoparticle filler based on the total weight of the paper material layer in which the nanoparticle filler is contained.

[0071] In some embodiments, the repulpable barrier material may include from about 0.1 wt.% to about 12 wt.%. from about 0.5 wt.% to about 10 wt.%, from about 1 wt.% to about 8 wt.%, or from about 3 wt.% to about 6 wt.% of the nano silica fillers based on the1036634300.1total weight of the paper material layer in which the nanoparticle filler is contained. In embodiments, the repulpable barrier material may include from about 3 wt.% to about 12 wt.% based on the total weight of the paper material layer in which the nanoparticle filler is contained. In still other embodiments, the repulpable barrier material may include from about 6 wt.% to about 10 wt.% of the nano silica fillers based on the total weight of the paper material layer in which the nanoparticle filler is contained.

[0072] Nanocellulose

[0073] The paper barrier material may comprise a nanocellulose material. Nanocellulose refers to a category of highly purified cellulosic materials obtained through mechanical and / or chemical processes aimed at isolating the smallest components of the cellulose fiber. An example of a suitable nanocellulose material is microfibrillated cellulose (MFC). MFC has fibers that ty pically range in diameter from 5 to 100 nm, with lengths varying from 1 to 10 pm. This type of nanocellulose is often referred to as either or both "microfibrillated cellulose," indicating the length of the fibrils on the micrometer scale, and synonymously as "nanofibrillated cellulose," representing its width on the nanometer scale. MFCs can be isolated by intensive mechanical processing of purified cellulose. Since the aspect ratio of MFC is in the range 70-100, this leads to a small percolation threshold, 0.7-1.0 vol. %. Thus, even small additions of these nanofibers can form a continuous netw ork within the paper bulk. Application of aqueous dispersions of MFCs in paper compositions even in the range of 2-10 weight % improves the mechanical properties of the resulting paper significantly. An example of commercially available MFC is Borregaard's Exilva F 01 -V, an insoluble microfibrillated cellulose, which consists of an entanglement of the cellulose fibers which has the ability to interact both physically through its extreme surface area and chemically through hydrogen bonding. Its novel nature gives it rheological and mechanical functionalities, which as an additive, imparts a unique combination of properties in finished product systems. Without being bound by any particular theory, the fibrillation process may produce many hydroxyl groups that become accessible to the matrix in a network, which may contribute to a very' high water retention capability'.

[0074] Hydrophobic Sizing Additive

[0075] The paper barrier material may optionally include a hydrophobic sizing additive. Most paper types consist of microfibril cellulose networks, which inherently render the paper porous and highly hydrophilic. These characteristics present challenges in numerous packaging applications due to the papers' natural deficiencies in providing effective barriers against gases, water, and grease. Hydrophobic sizing additives are substances added1136634300.1to paper to reduce the amount of liquid water it absorbs. These additives may be used to improve paper's printability, coatability, and water repellency. Hydrophobic sizing additives are usually added to the furnish, the aqueous suspension of fibers and other materials that will be formed into a sheet and dried on the paper machine. This process is called internal sizing. Hydrophobic additives can also be applied to the paper after it has been formed using a size press or vapor deposition. This process is called surface sizing. Some examples of hydrophobic sizing additives include, but are not limited to, ASA (alkenyl succinic anhydride), AKD (alkyl ketene dimer), rosin products, and Wood gum. Hydrophobic sizing additives, when employed, can be added in an amount of from about 0.05 wt. % to about 2 wt. %, from about 0.1 wt.% to about 1.75 wt.%, from about 0.2 wt.% to about 1.5 wt.%, from about 0.25 wt. % to about 1.25 wt.%, or from about 0.5 wt.% to about 1 wt.% of the dry weight of the paper. Examples of suitable non-starch hydrophobic surface sizing additives include, for example, anhydrides, dimers, polymers, copolymers, polymer latexes, etc., and may include, for example, one or more of styrene-maleic anhydride (SMA) copolymers; styrene-acrylic (SA) copolymers, such as styrene-acrylic acid (SAA) copolymers; alkylated melamines; rosin-based sizes (e.g.. rosin emulsion sizes, rosin soap sizes, etc.); styrenebutadiene (SB) copolymers; acrylonitrile-butadiene (AB) copolymers; alkyl ketene dimers (AKDs); polyacrylamides polymers or copolymers; etc.

[0076] Micro Cavitation of the Paper Bulk

[0077] In some embodiments, the repulpable barrier material has a plurality of cavities or pores formed between the paper fibers. The addition of a nanocellulose filler such as MFCs further acts as bridge between the paper fibers, increases the bond strength and fills the gaps to create a fine network of micro cavities. Microstructure of these cavities mainly depends on the paper fibers themselves, fiber length, fiber orientation distribution, contact area between fibers, and the number of hydrogen bonds in the matrix. It is expected that the MFCs when added to pulp is distributed in the gaps between the fibers or on the fiber surface and closely combined with the pulp fibers, which strengthens the adhesion between the fibers, fill the voids in the paper, and results in the formation of micro cavities in the paper bulk.

[0078] In some embodiments, the plurality7of micro cavities in the paper bulk are rendered water-tight by the presence of a hydrophobic sizing additive. Hydrophobic sizing agents are typically added to the furnish and coat the fiber surfaces with a molecular level layer of hydrophobicity. However, these agents do not obstruct the intended hydrogen bonding between the fibers, allowing the approach of forming micro cavities still effective.1236634300.1In some embodiments, the plurality of water-tight micro cavities in the paper bulk have associated nano filler particles in communication therewith. It is the intent of this invention to form a majority of water-tight micro cavities that are in communication with the nano filler particles to improve the moisture barrier properties of the repulpable barrier material. Without wishing to be bound by theory, it is believed that the presence of nano filler particles in communication with the cavities increases the amount of w ater that can be absorbed by the particle through the bulk phase or increases the probability that a given w ater molecule will interact, at least indirectly through the bulk phase, with a nano filler particle. The moisture absorbed by in contact with or bonded to the nano filler particle in communication with a cavity then increases the vapor pressure inside the cavity and stops additional moisture in vapor form from passing through the cavity. In other words, a cavity that is in communication with a nano filler particle that is saturated with absorbed moisture becomes a barrier to moisture transmission through the cavity. On the other hand, a cavity that is not in communication with a nano filler particle continues to transmit moisture vapor through the cavity without any resistance to the transmission. It is, therefore, desirable to have more cavities having one or more particles in communication therewith so that such cavities can function as a barrier to moisture vapor transmission and minimize the cavities without particles that let through moisture without any resistance.

[0079] Moisture Barrier Coating Layer

[0080] In one embodiment, the paper barrier material may include a moisture barrier coating material disposed on a surface of the paper barrier material. Several techniques are available for applying either single or multiple coating layers onto paper, including extrusion coating, curtain coating, size press coating, bar coating, and dip coating. Extrusion coating stands as one of the most conventional processes for applying paper coatings on an industrial scale. Extrusion coating may provide continuous and solvent-free operations, uniform coating finishes, and the effective elimination of pinholes and cracks. As an alternative to extrusion coating to enhance water repellency and moisture resistance (referred to as "holdout") of paper substrates, a coating of aqueous polymer emulsion can be applied to the paper. This moisture barrier coating, typically comprising an aqueous polymer emulsion, serves to impart water repellency and moisture resistance. Ideally, the moisture barrier coating should yield a smooth surface with adequate w ater holdout, using a minimal amount of the aqueous polymer emulsion to coat the paper surface to establish a continuous hydrophobic moisture barrier layer.1336634300.1

[0081] An aqueous emulsion coating composition designed to impart moisture barrier (hydrophobicity) benefits to the coated paper substrate typically comprises one or more water-dispersible emulsion polymers; polymers or copolymers which are dispersible in aqueous solvents (e.g., water) to form an aqueous polymer emulsion.

[0082] The water-dispersible emulsion polymers utilized in this context should exhibit several key characteristics. They should be capable of forming polymer particles that coalesce into a continuous film under typical drying temperatures employed in papermaking processes. Additionally, these polymers should possess heat-sealable properties, allowing for sealing at temperatures and durations comparable to or wi thin the range of materials like low- density polyethylene (LDPE) or polyethylene terephthalate (PET). Moreover, they must meet safety standards for contact with food or beverages if intended for such applications.

[0083] Suitable water-dispersible emulsion polymers may encompass a variety of materials, including but not limited to, polyethylene (PE) polymers (such as low-density polyethylene (LDPE) and copolymers thereof), polyethylene terephthalate (PET) polymers and copolymers, polyhydroxyalkanoate (PHA) polymers, polylactic acid (PLA) polymers, polyglycolic acid (PGA) polymers, polyvinyl acetate polymers, waxes, polyurethane polymers, epoxy resins, among others. Suitable commercially available PE polymer emulsions may include high density' polyethylene (HDPE), as well as low density polyethylene (LDPE) emulsions available, for example, Coating X300 from Michelman, MD-80 from Omnova. Berchem 4000 from Bercen. etc. Suitable commercially available PET polymer emulsions or modified PET emulsions may include EvCote Water Barrier 3000 from AkzoNobel, SFS 230HS and 250HS from Sustainable Fiber Solutions, etc.

[0084] Moisture Barrier Materials

[0085] The paper barrier materials may be employed to form all or a part of a moisture barrier material. In one embodiment, a moisture barrier material comprises, consists essentially of, or consists of a paper barrier material.

[0086] In accordance with FIG. l, a moisture barrier material 100 comprises a substrate 110 formed from a paper barrier material in accordance with the present technology.

[0087] In embodiments, the moisture barrier material may be provided as a multilayer material comprising one or more paper barrier layers optionally with one or more other moisture barrier layers. In some embodiments, water-tight micro cavitated structures with associated nano filler particles in communication therewith, by themselves, may not provide a suitable level of moisture barrier property for a particular application or use. As such, one or more moisture barrier layers or additional paper barrier layers may be employed. In one1436634300.1embodiment, a moisture barrier material may comprise two, three, four or more paper barrier layers disposed adjacent to one another.

[0088] Referring to FIG. 2, a moisture barrier material 200 comprises a paper barrier material layer 210 having a moisture barrier layer 220 disposed on surface 212 of the paper barrier layer. In this two layer configuration, either the paper barrier 210 or the moisture barrier layer 220 may be employed as the inner or outer layer of a package formed from the barrier material. In some embodiments, water-tight micro cavitated structures with associated nano filler particles in communication therewith, is combined with an outer layer comprising moisture barrier coating that is substantially free of the nano silica filler.

[0089] FIG. 3 shows an embodiment of a barrier material 300 comprising a paper barrier material 310 comprising a first moisture barrier layer 320 disposed on a surface 312 of the paper barrier layer 310, and a sealing layer 330 disposed on a surface 314 of the paper barrier layer 310.

[0090] FIG. 4 shows an embodiment of a barrier material 400 comprising a paper barrier material 410 comprising a first moisture barrier layer 420 disposed on a surface 412 of the paper barrier layer 410, and a second moisture barrier layer 430 disposed on a surface 414 of the paper barrier layer 410.

[0091] In some embodiments, the first outer layer and a second outer layer both comprise moisture barrier coating that is substantially free of the nano silica filler.

[0092] In some embodiments, water-tight micro cavitated structures with associated nano filler particles in communication therewith, is positioned between a first outer layer and a second outer layer with a first inner layer interposed in between, all three layers comprising moisture barrier coating that is substantially free of the nano silica filler. FIG. 5 shows a moisture barrier material 500 comprising (i) a first paper barrier material 510 disposed between a first inner layer 550 and a second outer layer 530 comprising a moisture barrier coating, and (ii) a second paper barrier material 520 disposed between the first inner layer 550 and a second outer layer 540 comprising a moisture barrier coating. This first inner layer is more effective in isolating the micro cavitated barrier layers when it constitutes a major portion of the multilayer structure, and in emodiments is in the range of from about 20% to about 60% of the overall thickness of the multilayer structure, from about 25% to about 55% of the overall thickness of the multilayer structure, or from about 30% to about 50% of the overall thickness of the multilayer structure.

[0093] FIG. 6 shows a moisture barrier material 600 comprising (i) a first paper barrier material 610 disposed between a first inner layer 650 and a second outer layer 6301536634300.1comprising a moisture barrier coating, and (ii) a second paper barrier material 620 disposed between the first inner layer 650 and a second outer layer 640 comprising a moisture barrier coating. In this embodiment, first inner layer 650 is a paper layer that is formed from a paper material other than the paper barrier material in accordance with the present technology. In particular, in one embodiment, the paper layer 650 is substantially free of a nano filler such as nano silica. The inner layer 650, similar to the layer 550, may be effective to separate or isolate the paper barrier material layers (610 and 620). In embodiments, the first inner layer 650 has a thickness in the range of from about 20% to about 60% of the overall thickness of the multilayer structure, from about 25% to about 55% of the overall thickness of the multilayer structure, or from about 30% to about 50% of the overall thickness of the multilayer structure. Employing a paper material as the first inner layer may allow for the structure to be repulpable when the first inner layer is present at higher thicknesses (e.g., from about 30 to about 50% of the overall thickness of the multilayer structure).

[0094] In some embodiments, the process of making a repulpable barrier material involve:

[0095] (A) Providing an aqueous pulp suspension that comprises hydrophobic sizing additive, nanocellulose additive, and a nano particle filler (e.g., in embodiments nano silica particles).

[0096] (B) Sheeting and drying the aqueous pulp suspension to obtain a dried paper or paperboard web.

[0097] (C) Drying the paper or paperboard web.

[0098] Step (A) involves providing an aqueous pulp suspension. The methods for forming such suspensions are well-established in the paper and paperboard industry and will not be elaborated upon in detail here. Although not obligator)’ for the invention, in embodiments, the pulp is subjected to bleaching to eliminate lignin to achieve the desired pulp brightness. Following completion of the bleaching process and subsequent washing and screening of the pulp, one or more refining steps are ty pically undertaken. Subsequently, the refined pulp is transferred to a blend chest, where it is blended with various additives and fillers.

[0099] In step (B) of this process, the pulp suspension from step (A) is sheeted and dried to produce a dried paper or paperboard web. Techniques and equipment for sheeting and drying pulp suspensions are widely recognized within the paper and paperboard industry.1636634300.1

[0100] In step (C) of this process, the paper or paperboard web is dried after treatment with the size composition. Techniques and equipment for drying paper or paperboard webs treated with a sizing composition are well-established in the paper and paperboard industry.

[0101] In some embodiments, the process of making a repulpable barrier material involve:

[0102] (A) Providing an aqueous pulp suspension that comprises hydrophobic sizing additive, nanocellulose additive, nano particle filler (e.g., in embodiments nano silica particles).

[0103] (B) Sheeting and dry ing the aqueous pulp suspension to obtain a dried paper or paperboard web.

[0104] (C) Coating the dried paper or paperboard web by applying a moisture barrier containing one or more hydrophobic polymers to at least one surface of the web.

[0105] (D) Dry ing the paper or paperboard web.

[0106] In step (C) of this process, the dried paper or paperboard web is coated by applying a water-based emulsion containing one or more hydrophobic polymers to at least one surface of the web. Techniques and equipment for treating a dried web of paper or paperboard with a water-based coating layer are widely recognized in the paper and paperboard industry.

[0107] Following dry ing, the paper may undergo one or more post-drying steps. For instance, the paper or paperboard web may be coated and / or calendered to attain the desired final caliper to enhance the smoothness and other properties of the web.

[0108] Packaging

[0109] A multilayer moisture barrier may itself be used as a packaging film or may be incorporated into or be treated to form a packaging film. Preferably, the packaging film is flexible and capable of sealing to itself or another film around a product. The packaging film can heat sealable, cold sealable, sealed with an adhesive such as a pressure sensitive adhesive, sealed via an ultrasonic weld, or the like. While FIG. 3 is described as having a sealing layer, it will be appreciated that any embodiment of the packaging material may employ a sealing layer. Sealing layers can be provided in any suitable manner, design, or arrangement. For example, the sealing layer can be a continuous layer or a patterned layer. The sealing layer can be applied over the entire layer or over selected area (e.g., along one or more edges).

[0110] One or both of the first and second outer layers of the multilayer moisture barrier can sen e as one or both of the outer layers of the packaging film.1736634300.1

[0111] If desired one or more layers can be added to the multilayer moisture barrier film by lamination to produce the packaging film. For example, if the first or second outer layers of the moisture barrier do not have suitable protective properties or sealing properties for the packing needs, layers having appropriate properties can be laminated to the moisture barrier.

[0112] In some embodiments, the inner polymeric layer of a packaging is coated to facilitate sealing. Any suitable seal-facilitating coating can be applied to the inner polymeric layer. Examples of suitable seal-facilitating coatings include cohesive cold seal coatings, such as acrylic emulsions, natural and synthetic latex materials, and the like, and combinations thereof. Such materials are commercially available from a number of manufacturers such as HB Fuller Co.; Bostik. Inc.; Ashland, Inc.; The Dow Chemical Company; and Henkel AG & Co.

[0113] In some cases, for example if the multilayer moisture barrier includes a polyolefin, such as polypropylene, as the first and second outer layer, the moisture barrier will have suitable sealing and protective properties to be used as a packaging film.

[0114] The moisture barrier material in accordance with the present technology can be used to form all or part of a packaging material including, but not limited to, a pouch, a bag, an overwrap, and the like. Some particular examples of packaging include, but are not limited to, pinch bottom pouches or bags, four-side seal bags, three-side seal bags, pillow bags, standup pouches, side gusset bags, quad seal bags, side weld bags, etc.

[0115] The moisture barrier material or packaging material comprising the moisture barrier material may also be used, for example as a lid or cover of an article. When used as a lid or cover, the packaging material may be configured with an appropriate adhesive to facilitate attachment of the packaging material to the packaging article.

[0116] Packaged Product

[0117] Any suitable product can be contained or sealed within a package containing a moisture barrier as described herein. Products for which moisture barrier protection is desirable may be advantageously contained or sealed within packages having a multilayer moisture barrier.

[0118] In some embodiments, a foodstuff is contained or sealed within a package containing a multilayer moisture barrier as described herein. Any suitable foodstuff can be contained or sealed within a package as described herein. The foodstuffs can be raw or natural foodstuffs or processed foodstuffs. Food processing includes the transformation of raw' ingredients into food or transforming forms of food into other forms of food. Food1836634300.1processing often includes using harvested crops or animal products to produce marketable and often long shelf-life products. Processed foodstuffs include products for which additional processing by a consumer may be desired prior to consumption. For example, a foodstuff for which heating, cooking, baking, or the like, may be desired by a consumer prior to consumption may be a processed foodstuff despite not being in its final form (e.g., being unheated, uncooked, unbaked, etc.) prior to delivery to a consumer.

[0119] Examples of processed foodstuffs that may be contained or sealed within a package as described herein include a confectionary, a gum, a bakery product, an ice cream, a daily7product, a fruit snack, a chip or crisp, an extruded snack, a tortilla chip or com chip, a popcorn, a pretzel, a nut, a snack bar, a meal replacement, a ready meal, a soup, a pasta, a canned food, a frozen processed food, a dried processed food, an instant noodle, a chilled processed food, an oil or fat, a sauce dressing or condiment, a dip, a pickled product, a seasoning, a baby food, a spread, a chip or a crisp such as chips or crisps comprising potato, com, rice, vegetable (including raw, pickled, cooked and dried vegetables), a fruit, a grain, a soup, a seasoning, a baked product such as a ready-to-eat breakfast cereal, hot cereal or dough, an ice cream such as a frozen yogurt, a dairy products such as a yogurt or cheese, ready meal, a soup, a pasta, a canned food, a frozen processed food, a dried processed food, an instant noodle, or a chilled processed food, a beverage including beverages that include fiber or protein a meat or a meat substitute, a pet food, an animal product, and a medical food.

[0120] In some embodiments, a foodstuff that may be contained or sealed within a package as described herein includes a vitamin supplement, an infant formula product, a medicinal or pharmaceutical product, or the like.

[0121] What has been described above includes examples of the present specification. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of descnbing the present specification, but one of ordinary skill in the art may recognize that many further combinations and permutations of the present specification are possible. Accordingly, the present specification is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

[0122] The foregoing description identifies various, non-limiting embodiments of a repulpable barrier material, a packaging material comprising such repulpable barrier material.1936634300.1and articles comprising such packaging material. Modifications may occur to those skilled in the art and to those who may make and use the invention. The disclosed embodiments are merely for illustrative purposes and not intended to limit the scope of the invention or the subject matter set forth in the claims.2036634300.1

Claims

1. CLAIMSWhat is claimed is:

1. A packaging material comprising a substrate having a first surface and a second surface opposite the first surface, the substrate layer comprising (i) a bulk layer of paper defining a plurality of cavities, and (ii) a filler particle that sorbs water, wherein at least one of the plurality of cavities has at least one filler particle in communication therewith.

2. The packaging material of claim 1, wherein the filler particle comprises surface hydroxyl groups.

3. The packaging material of claim 1 or 2, wherein the filler particle is selected from silica, anhydrous salts, molecular sieves, silica gels, clays, starches, ammonium chloride, calcium chloride, calcium carbonate, calcium oxide, potassium chloride, potassium carbonate, sodium chloride, sodium phosphate di-basic, sodium pyrophosphate, sodium nitrate, or a combination of two or more thereof.

4. The packaging material of any of claims 1-3. wherein the filler particle is selected from silica.

5. The packaging material of any of claims 1-4, wherein the filler particle has an average particle size of from about 1 nm to about 150 nm.

6. The packaging material of any of claims 1-5, wherein the filler particle has a surface area of from about 50 m2 / g to about 600 m2 / g.

7. The packaging material of any of claims 1-6 wherein the filler particle is present in the substrate in an amount of from about 0.1 wt.% to about 12 wt.% based on the weight of the substrate.

8. The packaging material of any of claims 1-7, wherein the substrate further comprises a nanocellulosic matenal.2136634300.19 The packaging material of claim 8, wherein the nanocellulosic material is selected from microfibrillated cellulose.

10. The packaging material of claim 8 or 9, wherein the nanocellulosic material is comprises the nanocellulosic material in an amount of from about 2 wt.% to about 10 wt.% baseed on the weight of the substrate.

11. The packaging material of any of claims 1-10 further comprising a hydrophobic sizing agent.

12. The packaging material of claim 11, where the hydrophobic sizing agent is disposed within the substrate.

13. The packaging material of any of claims 1-12 comprising a moisture barrier coating disposed on the first surface of the substrate, the second surface of the substrate, or both the first and second surface of the substrate.

14. The packaging material of claim 13 comprising a moisture barrier coating disposed on the first surface of the substrate.

15. The packaging material of claim 14 comprising a sealing layer disposed on the second surface of the substrate.

16. The packaging matenal of claim 14 comprising a moisture barrier coating disposed on the second surface of the substrate.

17. A package defining an interior space for holding a product, the package comprising the packaging material of any of claims 1-16.

18. The package of claim 17, wherein the package comprises a first package wall and a second package wall, wherein the interior space is defined between the first and second package wall, and the first and second package walls are formed from the packaging material of any of claims 1-16.2236634300.

119. The package of claim 17 comprising a container portion defining an interior space, and a cover disposed over the container portion, wherein the cover comprises the packaging material of any of claims 1-16.

20. An article comprising: a packaging material comprising a first outer layer; a second outer layer; an inner layer disposed between the first outer layer and the second outer layer; a first paper barrier layer disposed between the first outer layer and the inner layer; and a second paper barrier layer disposed between the second outer layer and the inner layer; the first and second paper barrier layers independently comprising (i) a bulk layer of paper defining a plurality of cavities, and (ii) a filler particle that sorbs water, wherein at least one of the plurality of cavities has at least one filler particle in communication therewith.

21. The article of claim 20, wherein the first outer layer, the second outer layer, and the inner layer are substantially free of nanofiller particles.

22. The article of claim 20 or 21, wherein the filler particle comprises surface hydroxyl groups.

23. The article of any of claims 20-22, wherein the filler particle is selected from silica, anhydrous salts, molecular sieves, silica gels, clays, starches, ammonium chloride, calcium chloride, calcium carbonate, calcium oxide, potassium chloride, potassium carbonate, sodium chloride, sodium phosphate di-basic, sodium pyrophosphate, sodium nitrate, or a combination of two or more thereof.

24. The article of any of claims 20-23, wherein the filler particle is selected from silica.

25. The article of any of claims 20-24, wherein the filler particle has an average particle size of from about 1 nm to about 150 nm.2336634300.

126. The article of any of claims 20-25, wherein the filler particle has a surface area of from about 50 m2 / g to about 600 m2 / g.

27. The article of any of claims 20-26, wherein the first and second paper barrier layers independently comprise the filler particle in in an amount of from about 0.1 wt.% to about 12 wt.% based on the weight of the substrate.

28. The article of any of claims 20-26, wherein the first and second paper barrier layers independently comprise further comprises a nanocellulosic material.29 The article of claim 28, wherein the nanocellulosic material is selected from microfibrillated cellulose.

30. The article of claim 27 or 28, wherein the nanocellulosic material is comprises the nanocellulosic material in an amount of from about 2 wt.% to about 10 wt.% baseed on the weight of the substrate.

31. The article of any of claims 20-30 further comprising a hydrophobic sizing agent.

32. The article of claim 31, where the hydrophobic sizing agent is disposed within the first and second paper barrier layers.

33. The article of any of claims 20-32. wherein the inner layer has a thickness that is from about 20% to about 60% of a total thickness of the packaging material.

34. The article of any of claims 20-33, wherein the inner layer has a thickness that is from about 30% to about 50% of a total thickness of the packaging material.2436634300.1

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