Starch and cellulose foam materials and uses thereof in paper packaging applications

Abstract

The present disclosure relates to starch and cellulose foam materials, to processes for their preparation, and to uses thereof as protective packaging materials in, e.g., paper packaging applications. These protective packaging materials may be biodegradable, compostable and / or recyclable.

Description

STARCH AND CELLULOSE FOAM MATERIALS AND USES THEREOF IN PAPERPACKAGING APPLICATIONSField of the Invention

[0001] The present invention relates to starch and cellulose foam materials, to processes for their preparation, and to uses thereof as protective packaging materials in, e.g., paper packaging applications. These protective packaging materials may be biodegradable, compostable and / or recyclable.Background of the Invention

[0002] The focus on sustainable solutions, particularly in the paper packaging industry, is growing rapidly as consumers and brands are becoming more aware of the environmental impacts. As a result, there is an increased need for bio-based and recyclable paper packaging solutions to replace petroleum-based ones, particularly for single-use articles.

[0003] Cellulose foam products are recyclable in the curb side paper recycling process but use high quantities of water and are slow to dry and manufacture. Cellulose based foams are typically produced at relatively low solids contents (2 - 8%), resulting in the requirement of a large amount of energy to remove the high water content. As a result, a vacuum is often used to aid in the removal of the water, with extensive convection or infrared drying energy and times being required to dry the foams completely. The high costs associated with this time and energy have acted as a barrier to commercialization for these types of foams.

[0004] Starch packaging “peanuts” or foams offer another biobased packaging material with low impact at end-of-life. These can be made from powder with low water content through twin screw extrusion or similar processes. These require landfill disposal or washing down a household drain. Some alternatives combine sheets of paper with a layer of starch peanuts to create insulated packaging materials, but an excess of starch compared to paper content can make these of low value in paper recycling.

[0005] U.S. Publication No. 2023 / 0124547 describes protective packaging materials and processes for their preparation.

[0006] U.S. Patent No. 10,259,151 describes a method of forming a molded fibrous product that involves foaming fibers in which the solids content may be 0.1-10%, preferably 0.5-5%. The process involves a dewatering step to remove water. This is typical of most cellulose foam processes today. The low solids content and dewatering step lead to slow process times and high energy requirements creating a barrier to entry in the commercial world.

[0007] German Publication No. DE 102018105384 describes a device and method of producing a fibrous foam. The method described therein is also a low solids content process, where water makes up 94 - 99% of the solution. The process requires a multiple step mixing procedure to foam. Additionally, a flotation injector is used for introducing air. The mold formation hold time is 12 - 24 hours. The cycle time being this long makes it difficult to commercialize as it is a complex process to carry out on a large scale.

[0008] U.S. Patent No. 7,563,830 describes a method for producing a foamed biodegradable product, in particular a thick-walled biodegradable foamed product. A starch-based biodegradable polymeric base material is extruded using water as a blowing agent. The extrudate is conditioned at a controlled temperature and humidity and then passed through a two-step microwave heating section. This can be a cumbersome process since it requires additional steps to condition and preheat the material prior to obtaining the final product. Additionally, the base of the product is starch and does not contain any fibers, making it undesirable in a paper waste stream since there is no reclaimable content.

[0009] U.S. Patent No. 7,989,524 describes a fiber-reinforced and starch-based composition and a multi-step process for its manufacture.

[0010] Chinese Publication No. CN 114106395 describes a starch-based material that contains fiber.

[0011] There is still a need for new economically viable processes to prepare biodegradable, compostable and / or recyclable foam compositions for use in paper packaging applications. The present invention addresses such needs. The processes described herein combine both nongelatinized starch and cellulose raw materials. The processes described herein lower the drying requirements of most cellulose foams but retain the recyclable nature of the product by increasing the solids with biobased, non-gelatinized starches.Summary of the Invention

[0012] The present invention is directed to foam compositions containing both cellulose fibers and starch and their use in packaging applications. The compositions have a high solids content, thereby helping to overcome challenges encountered using either purely cellulose or purely starch-based packaging products. The present invention is also directed to methods of manufacturing such foam compositions. In certain embodiments, the methods involve mechanical mixing in a cold state e.g., (less than about 50° C) and maintaining a product low in viscosity, thereby providing for easy pumping and application. In the methods described herein, a non -gelatinized starch starting material is gelatinized via heated drying, such as, e.g., dielectric heating.

[0013] The processes described herein use cellulose foam -forming methods combined with the synergistic effect of a non-gelatinized starch starting material to reduce the water content required, combine process steps into single unit operations for simplification, and reduce equipment expenditure. The compositions described herein add reclaimable fibers to the paper recycling streams, unlike purely starch foam products. The compositions and processes described herein also reduce the water content greatly from purely cellulose foam products available today, lowering the energy requirements for drying. The blend of cellulose and starch at high solids content sets (i.e., dries, cooks, set up, cures) effectively via the use of dielectric heating for foam drying, significantly reducing process time and enabling thick structures with high structural strength to be prepared. Using nongelatinized starch and maintaining a low process temperature also provides an acceptable viscosity for pumping and applying the foam.

[0014] The present inventors have also surprisingly found that a low water content is still sufficient for building adequate foam to take the place of water in breaking apart cellulose fibers so they can blend with the starch particles and allow for flow through pipes and application equipment. Fiber foams typically require much more water to create foam than the compositions and processes described herein.

[0015] In certain embodiments of the processes described herein, in order to ensure that the starch stays ungelatinized before a desired drying / gelatinizing step, mixing is performed in a cold state (such as, e.g., less than about 50° C). The use of mechanical mixing at, e.g., atmospheric pressure allows the cellulose and starch-based suspension to incorporate about, e.g., 65 to about95% air by volume. The foam is then carried in the cold state (such as, e.g., less than about 50° C) through a pump and to the application site where it may be applied to a web material suitable for the manufacture of packaging materials. The starch becomes gelatinized in a drying step where water is removed (vaporized).

[0016] In the processes described herein, continuous gelatinization of starch in the drying stage provides the binding and structural properties needed for a protective paper packaging application. Cellulose foam without a binder, or in this case starch, cannot be immediately dried in a dielectric heating system, as the foam will collapse and provide little structural support for packaging. Surprisingly, the starch provides stability for the foam during dielectric heating, maintaining the structure of the combined cellulose and starch foam.

[0017] The compositions and / or processes described herein exhibit one or more of the following advantages.• The compositions described herein are biobased and recyclable foams, which add paper recyclability to starch foams and makes cellulose foam economically viable to produce.• The foams prepared herein exhibit a high compressive strength for sufficient impact resistance for packaging.• The process described herein is a continuous process, which allows for faster production / commercial line speeds.• The simplified processes described herein allow for lower capital investment (less equipment & process steps needed).

[0018] Accordingly, in a first aspect, the present invention relates to a foamable composition. In one embodiment, the foamable composition comprises:(a) cellulose fibers;(b) a non-gelatinized starch;(c) a foaming agent;(d) water; and(e) optionally, an additive.

[0019] In one embodiment, the foamable composition comprises (a) about 5 wt. % to about 25 wt. % cellulose fibers, (b) about 5 wt. % to about 35 wt. % non-gelatinized starch, (c) about 0.1 wt. % to about 5 wt. % foaming agent, (d) about 40 wt. % to about 90 wt. % water; and (e) optionally, up to about 20 wt. % additive.

[0020] In one embodiment, the foamable composition comprises (a) about 10 wt. % to about 20 wt. % cellulose fibers, about 7 wt. % to about 30 wt. % non-gelatinized starch; (c) about 0.75 wt. % to about 2 wt. % foaming agent, (d) about 50 wt. % to about 80 wt. % water; and (e) optionally, up to about 5 wt. % additive.

[0021] In one embodiment, the total solids content of the foamable composition is between about 15 % and about 50 %, such as between about 25 % and about 50%. In certain embodiment, the total solids content of the foamable composition is about 15 %, about 20 %, about 25 %, about 30 %, about 35 %, about 40 %, about 45 %, or about 50 %.

[0022] In a second aspect, the present invention relates to a process for preparing a foamed composition. In one embodiment, the process comprises:(a) preparing a foamable composition comprising(i) cellulose fibers;(ii) a non-gelatinized starch;(iii) a foaming agent;(iv) water; and(v) optionally, an additive;(b) incorporating air into the foamable composition at a temperature less than about 60° C;(c) optionally, applying the foamable composition onto a substrate; and(d) removing water and gelatinizing the starch in the foamable composition to form the foamed composition.

[0023] In one embodiment of the second aspect, step (b) comprises mechanical mixing at a temperature less than about 60° C.

[0024] In one embodiment of the second aspect, after step (c) but before step (d), the process optionally further comprises a step of removing a portion of the water from the product of step (b) to form a partially dried product. In certain embodiments, the step of removing a portion of the water removes between about 30 wt. % and about 70 wt. %, such as between about 40 wt. % and about 60 wt. %, or about 50 wt. % of the initial water content from the product of step (b).

[0025] In another embodiment of the second aspect, the partially dried product is, optionally, molded into a desired form with any suitable tools, forms, or equipment before step (d) and then drying is completed on the molded shape with appropriate drying equipment, such as, for example dielectric, convection or infrared.

[0026] In another embodiment of the second aspect, the process further optionally comprises step (e) molding the product of step (d) into a desired form with any suitable tools, forms, or equipment.

[0027] In certain embodiments, the desired form may be a folded form, a shaped three- dimensional package, a flat sheet with scored markings for later folding, an embossed sheet with patterns, or a sheet of an initial thickness when applied wet but with various thickness levels after forming with pressure and, optionally, heat.

[0028] Accordingly, another embodiment of the second aspect is directed to a process for preparing a foamed composition comprising:(a) preparing a foamable composition comprising(i) cellulose fibers;(ii) a non-gelatinized starch;(iii) a foaming agent;(iv) water; and(v) optionally, an additive;(b) incorporating air into the foamable composition at a temperature less than about60° C;(c) optionally, removing a portion of the water from the product of step (b) to form a partially dried product, and, optionally, molding the partially dried product into a desired form (e.g., with any suitable tools, forms, or equipment);(d) optionally, applying the product of step (b) or step (c) onto a substrate;(e) removing additional water and gelatinizing the foamable composition to form the foamed composition; and(f) optionally, molding the product of step (e) into a desired form (e.g., with any suitable tools, forms, or equipment).

[0029] Substrate herein may be a molding belt to form the molded good and then subsequently removed to form the stand-alone finished molded good. In another embodiment, the substrate herein may be a cellulosic substrate where the foam is applied and adhered onto the cellulosic substrate. The substrate can also be envisioned to be made from a different material, e.g., foil, film, plastic, metal, and the like.

[0030] In one embodiment of the second aspect, step (b) (e.g., mixing / foaming) is conducted at a temperature below about 60°C, such as below 50° C, below about 45° C, below about 40° C, below about 35° C, below about 30° C or below about 25° C.

[0031] For example, in certain embodiments, step (b) (e.g., mixing / foaming) is performed at temperatures between about 20° C and about 60°C, between about 20° C and about 55° C, between about 20° C and about 50° C, between about 20° C and about 45° C, between about 20° C and about 40° C, between about 20° C and about 35° C, between about 20° C and about 30° C or between about 20° C and about 25° C.

[0032] In additional embodiments, step (b) (e.g., mixing / foaming) is performed at temperatures between about 25° C and about 60°C, between about 25° C and about 55° C, between about 25° C and about 50° C, between about 25° C and about 45° C, between about 25° C and about 40° C, between about 25° C and about 35° C, or between about 25° C and about 30° C.

[0033] In certain embodiments, step (b) (e.g., mixing / foaming) is performed at temperatures between about 20° C and about 55°C or between about 35° C and about 45° C.

[0034] In certain embodiments, step (b) (e.g., mixing / foaming) is conducted for a time less than about 25 minutes, such as less than about 15 minutes.

[0035] In one embodiment of the second aspect, the water is removed by dielectric heating.

[0036] In a third aspect, the present invention relates to an article comprising:(a) a foamed composition comprising:(i) cellulose fibers;(ii) a gelatinized starch;(iii) a foaming agent;(iv) a plurality of air pockets; and(v) optionally, an additive.

[0037] In one embodiment, the foamed composition comprises about 65 to about 95 %, such as between about 75 % and about 85 % air (e.g., air provided by the plurality of air pockets present in the foamed composition).

[0038] In one embodiment, the article further comprises (b) one or more substrates.

[0039] In certain embodiments, the one or more substrates is, independently, a cellulosic substrate, a metal substrate, a plastic substrate, or any combination thereof.

[0040] In certain embodiments, the one or more substrates is, independently, paper, a corrugate, a compostable polymer film, a biodegradable polymer film, a biobased film, cellophane, a polyester film, a polypropylene film, a polyethylene film, a metalized film, a recyclable paper, a recycled paper, a recyclable coated paper, a recyclable metal vapor deposited paper, or any combination thereof.

[0041] In certain embodiments, the article is in the form of an envelope, a pouch, a bag, a box, a carton, a case, a lid, a wrap, a clamshell, a cup, a flat thermally insulating sheet, a molded three- dimensional package element, a folded package element, or a food container with adhesive.

[0042] In additional embodiments of any of the compositions or processes described herein, the cellulose fibers comprise softwood virgin fibers, hardwood virgin fibers, recycled softwood virgin fibers, recycled hardwood virgin fibers, or any combination thereof.

[0043] In additional embodiments of any of the compositions or processes described herein, the cellulose fibers comprise kraft pulp fibers.

[0044] In additional embodiments of any of the compositions or processes described herein, the non-gelatinized starch is selected from the group consisting of non-gelatinized potato starch, non-gelatinized wheat starch, non-gelatinized com starch, non-gelatinized tapioca starch, nongelatinized rice starch, or any combination thereof.

[0045] In additional embodiments of any of the compositions or processes described herein, the foaming agent is an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or any combination thereof.

[0046] In additional embodiments of any of the compositions or processes described herein, the surfactant is selected sodium dodecyl sulfate, sodium dioctyl sulfosuccinate, dodecyldimethylamine oxide, stearyl alcohol, glyceryl laurate, polysorbate, cetostearyl alcohol, starch, sucrose, hexadecyl palmitate, lauryl dimethylamine oxide (LDAO), coamidopropyl betaine (CAPB), ethanolamine, sorbitol, disodium dihydrogen ethylene diaminetetraacetate, sulfosuccinates, or any combination thereof.

[0047] In additional embodiments of any of the compositions or processes described herein, the additive is selected from anti-fungal agents, preservatives, biocides, plasticizers, tackifiers, salts, starches, unexpanded microspheres, expanded microspheres, calcium carbonate, clay, nanocellulose, nanocrystalline cellulose, UV dyes, dyes, pigments, defoamers, humectants, waxes, phase-change materials, microencapsulated chemicals, plasticizers, tackifiers, adhesion promoters (e.g. EGDA, PEI), crosslinkers, polyether compounds, rheology modifiers, or any combination thereof.Brief Description of the Drawings

[0048] FIG. 1 is an exemplary schematic of apparatus that may be used in any of the processes described herein.

[0049] FIG. 2 depicts exemplary discrete foam elements applied onto a substrate and dried open- faced.

[0050] FIG. 3 depicts exemplary discrete foam elements applied to a bottom substrate with a laminating top substrate.

[0051] FIG. 4 depicts an exemplary continuous foam sheet applied to a bottom substrate and dried open faced.

[0052] FIG. 5 depicts an exemplary continuous foam sheet applied to a bottom substrate and laminated with a top substrate.

[0053] FIG. 6 shows a foam composition of the present invention prepared according to Example 1.

[0054] FIG. 7 shows a composition prepared according to Sample 4 of Example 6 (using 40 wt. % non-gelatinized starch).Detailed Description of the Invention

[0055] As used herein, the term “total solids content” refers to the weight percentage of solids in the foamable composition prior to any drying step.

[0056] As used herein, the term “about” when referring to a number or a numerical range means that the number or numerical range referred to is an approximation within experimental variability (or within statistical experimental error), and thus the number or numerical range may vary from, for example, between 1% and 15% of the stated number or numerical range.

[0057] As used herein, the term “comprising” (and related terms such as “comprise” or “comprises” or “having” or “including”) includes, but is not limited to, those embodiments, for example, an embodiment of any composition of matter, composition, method, or process, or the like, that “consist of’ or “consist essentially of’ the described features.

[0058] Any use of the word “or” herein is intended to be inclusive and is equivalent to the expression “and / or,” unless the context clearly dictates otherwise. As such, for example, the expression “A or B” means A, or B, or both A and B. Similarly, for example, the expression “A, B, or C” means A, or B, or C, or any combination thereof.

[0059] All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (for example, the range of "from 2 to 10" is inclusive of the endpoints, 2 and 10, and all the intermediate values). The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value; they are sufficiently imprecise to include values approximating these ranges and / or values. As used herein, approximating language may beapplied to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about," may not be limited to the precise value specified, in some cases. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. The modifier "about" should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression "from about 2 to about 4" also discloses the range "from 2 to 4." The term "about" may refer to plus or minus 10% of the indicated number. For example, "about 10%" may indicate a range of 9% to 11 ", and "about 1" may mean from 0.9-1.1. Other meanings of "about" may be apparent from the context, such as rounding off, so, for example "about 1" may also mean from 0.5 to 1.4.Cellulose Fibers

[0060] The cellulose fibers used in any of the embodiments described herein may be wood fibers. The wood fibers can be virgin or recycled fibers, or a combination thereof. The virgin or recycled fibers can be hardwood fibers, for example, fibers produced from a deciduous tree. The wood fibers can be softwood fibers, for example, fibers produced from a coniferous tree.

[0061] The wood fibers used in in any of the embodiments described herein can be a combination of hardwood fibers and softwood fibers. The wood fibers can be softwood virgin wood fibers, such as, softwood virgin kraft pulp. The wood fibers can be kraft pulp fibers, fluff pulp fibers, Northern bleached softwood kraft (NBSK) pulp fibers, Southern bleached softwood kraft (SBSK) pulp fibers, virgin pulp fibers, bleached virgin pulp fibers, bleach virgin softwood, newsprint, recycled newsprint, recycled pulp fibers, deinked pulp fibers, bleached pulp fibers, or any combination thereof.

[0062] In some embodiments, the wood fibers used in any of the embodiments described herein comprise kraft pulp fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise fluff pulp fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise NBSK fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise SBSK fibers. In some embodiments, the wood fibers used in in any of the embodiments described herein comprise recycled fibers. In some embodiments, the wood fibers used in any of the embodimentsdescribed herein comprise deinked fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise bleached fibers.

[0063] The wood fibers used in in any of the embodiments described herein can include wood fibers of any species typically used for manufacturing paper products. The wood fibers suitable for use in in any of the embodiments described herein include, for example, spruce fibers, pine fibers, fir fibers, western Hemlock fibers, balsam fibers, cedar fibers, or a combination thereof. In some embodiments, the wood fibers used in any of the embodiments described herein comprise spruce fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise pine fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise fir fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise western Hemlock fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise balsam fibers. In some embodiments, the wood fibers used in any of the embodiments described herein comprise cedar fibers. In some embodiments, synthetic fibers can be added, in addition, to the wood fibers to form a composition. Synthetic fibers can be made from polymeric materials, including, but not limited to, polyester fibers and / or acrylonitrile fibers.

[0064] In certain embodiments, the wood fibers have a fiber length of about 0.5 mm to about 5 mm. Softwood fibers can measure from about 2 to about 4 mm (about 0.08 to about 0.16 inch) in length. Hardwood fibers can measure from about 0.5 to about 1.5 mm (about 0.02 to about 0.06 inch). Recycled fibers can have a reduced length of about 0.01 to about 5 mm. In some embodiments, the wood fibers have a fiber length of about 0.5 mm to about 4 mm. In some embodiments, the wood fibers have a fiber length of about 0.5 mm to about 3 mm. In some embodiments, the wood fibers have a fiber length of about 0.5 mm to about 2 mm. In some embodiments, the wood fibers have a fiber length of about 0.5 mm to about 1 mm. In some embodiments, the wood fibers have a fiber length of about 1 mm to about 4 mm. In some embodiments, the wood fibers used have a fiber length of about 2 mm to about 4 mm. In some embodiments, the wood fibers have a fiber length of about 3 mm to about 4 mm. For example, the wood fibers have a fiber length of about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, about 1, about 1.1, about 1.2, about 1.3, about 1.4, about 1.5, about 1.6, about 1.7, about 1.8, about 1.9, about 2, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, about 2.7, about 2.8,about 2.9, about 3, about 3.1, about 3.2, about 3.3, about 3.4, about 3.5, about 3.6, about 3.7, about 3.8, about 3.9, or about 4 mm.

[0065] In certain embodiments, the wood fibers have a fiber width of about 20 m to about 35 pm, for example about 20 pm to about 25 pm. In some about, the wood fibers have a fiber width of about 20 pm to about 30 pm. In some about, the wood fibers have a fiber width of about 25 pm to about 30 pm. In some about, the wood fibers have a fiber width of 30 pm to 35 pm. For example, the wood fibers about have a fiber length of about 20, about 21, about 22, about 23, about 24, about 25, about 26, about 27, about 28, about 29, about 30, about 31, about 32, about 33, about 34, or about 35 pm.

[0066] In certain embodiments, the wood fibers have a weight of about 5 million fibers per gram to about 30 million fibers per gram. In some embodiments, the wood fibers have a weight of about 5 million to about 10 million fibers per gram. In some embodiments, the wood fibers have a weight of about 10 million to about 15 million fibers per gram. In some asp embodiments ects, the wood fibers have a weight of 15 million to 20 million fibers per gram. In some embodiments, the wood fibers have a weight of 20 million to 25 million fibers per gram. In some embodiments, the wood fibers have a weight of 25 million to 30 million fibers per gram. For example, the wood fibers have a weight of about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24, about 25, about 26, about 27, about 28, about 29 or about 30 million fibers per gram.

[0067] In certain embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.5 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.1 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.15 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.2 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.25 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.3 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.35 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.4 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.05 mg / m to about 0.45 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.1 mg / m to about 0.2mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.2 mg / m to about 0.3 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.3 mg / m to about 0.4 mg / m. In some embodiments, the wood fibers have a fiber coarseness of about 0.4 mg / m to about 0.5 mg / m. For example, the wood fibers used in the disclosed methods and compositions have a fiber coarseness of about 0.05, about 0.1, about 0.15, about 0.2, about 0.25, about 0.3, about 0.35, about 0.4, about 0.45 about or 0.5 mg / m.

[0068] Wood fibers suitable for use in any of the processes and compositions described herein may be, for example, softwood kraft pulp (Mercer Peace River Pulp Ltd.) comprising White Spruce (Picea glauca) (>90%) and Lodgepole Pine (Pinus contortd) (<10%), e.g., having fiber length of 2.39 mm, fiber width of 27.4 pm, weight of 8.7 million fibers per gram, fiber coarseness of 0.14 mg / m.Starches

[0069] The starch used in any of the embodiments described herein can be sourced from potato, wheat, tapioca, corn, rice, or any combination thereof. The starch can be unmodified or, in part, modified.

[0070] In the foamable compositions according to any of the embodiments described herein, the starch is ungelatinized (non-gelatinized). In certain embodiments, the starch is unmodified, nongelatinized starch from corn, tapioca, or potato origins.

[0071] In certain embodiments, any of the foamable compositions described herein comprises about 5 to about 35 wt. % non-gelatinized starch, such as about 7 to about 30 wt. % nongelatinized starch.

[0072] In additional embodiments, any of the foamable and / or foamed compositions described herein comprises about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, about 8, about 8.5, about 9, about 9.5, about 10, about 10.5, about 11, about 11.5, about 12, about 12.5, about 13, about 13.5, about 14, about 14.5, about 15, about 15.5, about 16, about 16.5, about 17, about17.5, about 18, about 18.5, about 19, about 19.5, about 20, about 20.5, about 21, about 21.5, about 22, about 22.5, about 23, about 23.5, about 24, about 24.5, about 25, about 25.5, about 26, about 26.5, about 27, about 27.5, about 28, about 28.5, about 29, about 29.5, about 30, about30.5, about 31, about 31.5, about 32, about 32.5, about 33, about 33.5, about 34, about 34.5, or about 35 wt. % starch.Foaming Agents (Surfactants)

[0073] In one embodiment, the foaming agents described herein are surfactants. The surfactants suitable for use in any of the compositions described herein can be an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or any combination thereof. In some embodiments, the surfactant comprises an anionic surfactant. In some embodiments, the surfactant comprises a cationic surfactant. In some embodiments, the surfactant comprises an amphoteric surfactant.

[0074] Surfactants suitable for use in any of the compositions and / or methods described herein include sodium dodecyl sulfate, sodium dioctyl sulfosuccinate, dodecyldimethylamine oxide (DDAO), stearyl alcohol, glyceryl laurate, polysorbate, cetostearyl alcohol, starch, sucrose, hexadecyl palmitate, lauryl dimethylamine oxide (LDAO), coamidopropyl betaine (CAPB), ethanolamine, sorbitol, disodium dihydrogen ethylene diaminetetraacetate, sulfosuccinates, or a combination thereof.Water

[0075] The foamable compositions described herein include water, such as between about 40 wt. % and about 90 wt. % water, or between about 50 wt. % and about 80 wt. % water.

[0076] The water may be any water typically used in the manufacture of paper products and can include fresh water, spring water, purified water, distilled water, reverse osmosis water, and the like. Those of ordinary skill in the art will understand that the water used in the compositions and methods described herein can include trace amounts of minerals, inorganic compounds, and organic compounds.

[0077] In some embodiments, the foamable compositions include about 40 wt. % to about 50 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 50 wt. % to about 60 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 60 wt. % to about 70 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 70 wt. % toabout 80 wt. % water. In some embodiments any of the foamable compositions described herein includes about 80 wt. % to 90 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 40 wt. % to 80 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 40 wt. % to about 70 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 40 wt. % to about 60 wt. % water. In some embodiments, any of the foamable compositions described herein includes about 50 wt. % to about 75 wt. % water. For example, any of the foamable compositions described herein includes about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, or about 90 wt. % water.Additives

[0078] The compositions described herein may optionally include one or more additives.

[0079] Suitable additives include, but are not limited to, anti-fungal agents, preservatives, biocides, plasticizers, tackifiers, salts, starches, thickeners, unexpanded microspheres, expanded microspheres, calcium carbonate, clay, nanocellulose, nanocrystalline cellulose, UV dyes, dyes, pigments, defoamers, humectants, waxes, phase-change materials, microencapsulated chemicals, plasticizers, tackifiers, adhesion promoters (e.g. EGDA, PEI), crosslinkers, polyether compounds, rheology modifiers, or any combination thereof.

[0080] Microspheres suitable for use in the compositions described herein are described in, for example, U.S. Publication Nos. 2021 / 0214581, 2019 / 0284438 and 2019 / 0062028 and U.S. Patent No. 10,100,204, the entire contends of each of which is incorporated herein by reference.

[0081] The expandable microspheres can expand in size in the presence of heat and / or RF radiation. The microspheres useful in the present invention include, for example, heat expandable polymeric microspheres, including those having a hydrocarbon core and a polyacrylonitrile shell (such as those sold under the trade name DU ALITE®) and other similar microspheres (such as those sold under the trade name EXPANCEL®). The expandable microspheres may have any unexpanded size, including from about 5 microns to about 30 microns in diameter. In the presence of heat or radiation, the expandable microspheres of the present invention can increase in diameter by about 3 times to about 10 times the original size. Upon expansion of the microspheres in the composition, the composition becomes a foam-likematerial, which has improved insulation properties. The microspheres are typically made of plastic or polymeric shells and a blowing agent is inside the shell, designed to activate upon reaching specific temperatures.

[0082] In some embodiments, the compositions described herein do not include an additive that is an inorganic ionic salt, that is, the compositions described herein include about 0 wt. % of an inorganic ionic salt.

[0083] In some embodiments, the compositions described herein include an additive that is an inorganic ionic salt.-In some embodiments, the inorganic ionic salt may be present in the composition in an amount up to about 10 wt. %.

[0084] Suitable inorganic ionic salts for use in the compositions described herein include, but are not limited to, sodium chloride, calcium chloride, magnesium chloride, aluminum nitrate, ammonium zirconium, or any combination thereof. Sodium chloride is a particularly preferred inorganic ionic salt.

[0085] In some embodiments, the foamable compositions described herein consist of the cellulose fibers, the non-gelatinized starch, the foaming agent, and water. In other aspects, the compositions described herein consist essentially of the cellulose fibers, the non-gelatinized starch, the foaming agent, water, and additional elements that do not materially affect the basic and novel characteristics of the compositions for use in producing padded packaging materials.

[0086] In some embodiments, the compositions described herein comprise the cellulose fibers, the non-gelatinized starch, the foaming agent, water, and an additive (i.e., one or more additives). Those compositions including an additive include a non-zero wt. % of the additive up to about 20 wt. % of the additive. The additive can include a single additive, or the additive can comprise more than one additive. If the compositions described herein include more than one additive, the total, combined amount of the additives will be from a non-zero wt. % up to about 20 wt. %. In some embodiments, the compositions described herein include up to about 20 wt. % of additives. In some embodiments, the compositions described herein include up to about 15 wt. % of additives. In some embodiments, the compositions described herein include up to about 10 wt. % of additives. In some embodiments, the compositions described herein include up to about 5 wt. % of additives. In some embodiments, the compositions described herein include up to about 2 wt. % of additives. For example, the compositions described herein can include a non-zero wt. % that is less than about 0.1 wt. %, about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6,about 0.7, about 0.8. about 0.9, about 1, about 1.5, about 2, about 2.5, about 3, about 3.5, about 4, about 4.5, about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, about 8, about 8.5, about 9, about 9.5, about 10, about 10.5, about 11, about 11.5, about 12, about 12.5, about 13, about 13.5, about 14, about 14.5, about 15, about 15.5, about 16, about 16.5, about 17, about 17.5, about 18, about 18.5, about 19, about 19.5 or about 20 wt. % of additive.Substrates

[0087] The substrates described herein can be any web material suitable for the manufacture of packaging materials. For example, the substrate (such as a bottom and / or or a top (laminate) substrate) can independently be comprised of paper, corrugate, compostable polymer film, biodegradable polymer film, biobased films, cellophane, polyester film, polypropylene film, polyethylene film, metalized film, recyclable paper, recycled paper, recyclable coated paper, recyclable metal vapor deposited paper, or any combination thereof. In certain embodiments for the compositions disclosed herein, the substrate(s) are paper or fiber-based in nature (corrugate, recycled paper, coated paper, etc.).Articles

[0088] In certain embodiments the article is paper packaging product, such as, for example, an envelope, a pouch, a bag, a box, a carton, a lid, a wrap, a clamshell, a cup, a molded three- dimensional package element, a folded package element, or a food container with adhesive.

[0089] Exemplary parameters for the compositions and methods described herein are shown in Table 1.TABLE 1Processes

[0090] FIG. 1 is an exemplary schematic of apparatus that may be used in any of the processes described herein.

[0091] In the exemplary apparatus, 1, 2 and 3 are supply streams to the mixing tank 4. Stream 1 is a supply stream for cellulosic wood fibers. Stream l is a supply stream for non-gelatinized starch and other solid additives. Stream 3 is a supply stream for water. The mixing tank 4 is where the materials are mixed into a homogenous composition and foamed to, e.g., about 65 % to about 99 % air by volume. The homogenous foam 5 is then pumped 6 to the application site 7 whereby the foam is applied to a substrate (e.g., a web substrate) 8. The substrate with applied foam 8 is then passed through a drier 9 where water is removed (vaporized) and the starch is gelatinized. The resulting product 10 can be used for paper packaging applications.

[0092] FIGS. 2-5 depict representative products that can be produced in stream 10 of FIG. 1.

[0093] FIG. 2 depicts exemplary discrete foam elements applied onto a substrate and dried open- faced.

[0094] FIG. 3 depicts exemplary discrete foam elements applied to a bottom substrate with a laminating top substrate.

[0095] FIG. 4 depicts an exemplary continuous sheet applied to a bottom substrate and dried open faced.

[0096] FIG. 5 depicts an exemplary continuous foam sheet applied to a bottom substrate and laminated with a top substrate.

[0097] FIG. 6 shows a foam composition prepared according to a process of the present invention prepared according to Example 1.

[0098] FIG. 7 shows a composition prepared according to Sample 4 of Example 6 (using 40 wt. % non-gelatinized starch).

[0099] In one embodiment, the processes described herein include a singular mixing process step. In this process step, the raw materials are added to the mixing tank. The tank is configured with high shear turbine blades. This configuration works to disintegrate the compacted wood fibers while homogenizing the mixture into a foam. For the compositions described herein, the mixing and foaming time may be less than about 25 minutes, less than about 15 minutes, or about 5 to about 20 minutes, depending on the desired air content. In one embodiment, the composition is foamed to an air content of about 65 vol. % to about 99 vol. %, such as about 75 vol. % to about 85 vol. %. Mixing and foaming is performed at temperatures to ensure that the starch remains non-gelatinized.

[0100] In certain embodiments, e.g., to prevent an increase in viscosity due to swollen or gelatinized starch, the mixing / foaming (e g., step (b) of the second aspect, incorporating air into the foamable composition) is performed at temperatures below about 60°C, such as below 50° C, below about 45° C, below about 40° C, below about 35° C, below about 30° C or below about 25° C.

[0101] For example, in certain embodiments, the mixing / foaming is performed at temperatures between about 20° C and about 60°C, between about 20° C and about 55° C, between about 20° C and about 50° C, between about 20° C and about 45° C, between about 20° C and about 40° C, between about 20° C and about 35° C, between about 20° C and about 30° C or between about 20° C and about 25° C.

[0102] In additional embodiments, the mixing / foaming is performed at temperatures between about 25° C and about 60°C, between about 25° C and about 55° C, between about 25° C and about 50° C, between about 25° C and about 45° C, between about 25° C and about 40° C, between about 25° C and about 35° C, or between about 25° C and about 30° C.

[0103] In certain embodiments, the mixing / foaming is performed at temperatures between about 20° C and about 55°C or between about 35° C and about 45° C.

[0104] In certain embodiments, the mixing / foaming time is less than about 25 minutes, such as less than about 15 minutes. For example, the mixing / foaming time may be between about 5 and about 25 minutes, between about 5 and about 20 minutes, between about 5 and about 15 minutes, between about 5 and about 10 minutes, between about 10 and about 25 minutes, between about10 and about 25 minutes, between about 10 and about 15 minutes, between about 15 and about 25 minutes or between about 15 and about 20 minutes. The reduced mixing time, high air content and low mixing / foaming temperature are all advantages of the processes described herein.

[0105] In the processes described herein, the foam can be pumped using any method known in the art wherein the temperature of the foam remains below about 60° C (such as below 50° C, below about 45° C, below about 40° C, below about 35° C, below about 30° C or below about 25° C). Increasing the temperature beyond, e.g., about 60° C may lead to a significant increase in foam viscosity due to the starch swelling and beginning to gelatinize. This can lead to pump or application site blockages.

[0106] The foams described herein may be applied to a substrate using any method known in the art.Water Removal (Drying)

[0107] The foamable compositions described herein are dried to become a functional product.

[0108] Suitable drying methods for use in any of the processes described herein include dielectric heating, such as radio frequency or microwave heating, convectional heating, or any combination thereof.

[0109] Preferably, dielectric heating is used at least in part for the removal (vaporization) of water and the gelatinization of the starch. While not wishing to be bound to any particular theory, the passing of alternating electrical current through the product allows for uniform and rapid heating of the product. This internal heating allows for the starch gelatinization to occur at rapid rates at the same time the water is vaporized. Dielectric heating is the preferred method for removing water from thick products (about 3 to about 100 mm) and allows for different web substrates to be utilized. Convectional heating methods can be used but tend to remove the water slower than dielectric heating methods. As a result, the starch gelatinization may be less uniform or inefficient by this means of heating. This results in a weaker end product, specifically for thicker elements. Convection heating may be used with very thin foam layers.

[0110] Dielectric heating, electronic heating, radio frequency (RF) heating, and high-frequency heating, all interchangeably used herein, is the process in which high-frequency alternating electric field or radio wave heats a dielectric material. RF heating is distinguishable frommicrowave heating. Industrial radio frequencies operate between approximately 2 MHz and 300 MHz with typical wavelengths of about 141 to about 24 feet (43 to 7.3 meters). Industrial microwave systems use frequencies over 300 MHz with typical wavelengths of about 13 to about 5 inches (33 and 12 cm).

[0111] In certain embodiments, the processes described herein utilize dielectric RF heating of a foamable waterborne composition. RF creates an alternating electric field between a dielectric material, namely, polar water molecules. The article is conveyed between the electrodes causing the water molecules in the composition to continuously reorient to face opposite electrodes. Friction from this molecular movement causes the rapid heating. RF operates at much lower frequency than microwave heating and is associated with lower health risks than microwaves. RF is also suitable for heating bulkier and odd-shaped containers due to its higher depth of penetration. RF heating also allows for fast throughput of making articles. The composition must be designed to accommodate this fast throughput method to maximize solid contents in the composition. It is preferable that the water molecules to be efficiently driven off without leaving unsightly wrinkles or unevenness on the substrates. RF heating provides a uniform and faster egress of water from the composition, at a faster throughput. The uniform and evenness of the coalesced coating provides uniform thermal insulation to the article and minimizes unsightly wrinkles on the substrates, while increasing the production.

[0112] In additional embodiments, partial drying may be achieved through dielectric heating, while the removal of additional excess moisture may subsequently be achieved using convectional and / or dielectric heating.ExamplesExample 1

[0113] In this example, the components shown in Table 2 were mixed using a high shear mixer resulting in a foam with the physical properties shown in Table 3. The foam was approximately 36.2 % total solids and had a wet foam density of 169 g / L. See FIG. 6. The total solids was measured by weighing a small sample and recording its mass. Then that sample was placed in an oven set to 266°F for at least 30 minutes. The sample was allowed to cool for 1 minute uponremoval from the oven and then weighed again. The total solids was calculated by the change in mass before and after heating divided by the starting (wet) weight. The wet foam density was measured by first taring a graduated beaker on scale. Then, about 50 grams of the foam was added to the beaker, and the actual mass was recorded. The beaker was gently tapped against the counter to even out the foam and the volume was recorded. The density was then calculated by dividing the recorded mass by the recorded volume. The total air content was calculated using the initial and final volume of the foam before mixing and after mixing as the mixing occurs in a graduated beaker. The air content is calculated by the change in volume divided by the final volume.

[0114] The foam was then applied to a paper substrate in about 0.8-gram dots and placed in a 1000-Watt microwave to dry. The samples required about 75 seconds of microwave heat to dry. The resulting element had a dry foam density of about 70 g / L. The dry foam density was measured by carefully taking a small sample of the dried foam and cutting it into a 1” x 1” square. The sample was weighed on a balance and the mass was recorded. The thickness of the sample was measured using a micrometer. The volume of the sample was calculated by multiplying the length, width and thickness of the sample. The density was then calculated by dividing the recorded mass by the calculated volume.TABLE 2TABLE 3Example 2

[0115] This example demonstrates the effect of processing temperature on the manufacturing process. Samples 1-4 were prepared as shown in Table 4.TABLE 4

[0116] For Sample 4, the temperature of the foam rose to 68.5° C and the starch began to swell in the foam. This rapid increase in viscosity in the foam caused the pump and application site to clog up. The line had to be stopped and washed out to continue processing. Samples 1-3 represent successful trials, where the foam was processed below the gelatinization point of the starch and no process issues were noted.Example 3

[0117] This example demonstrates the benefit of using a starch and fiber-based foam compared to using a starch-based or fiber-based foam alone. Samples 1-3 were prepared as shown in Table 5.TABLE 5

[0118] For Sample 1 (starch in a 50% blend with water), using only mechanical mixing and microwave drying, a very stiff and dense element is created. When using ungelatinized starch, it is increasingly difficult to create a foam consistency. Too little starch creates a foamy but watery solution but too much starch creates a viscous paste-like suspension. Air doesn't incorporate well into this suspension using mechanical mixing alone. Additional equipment would be needed to produce a stable foam at high air contents.

[0119] Mechanical mixing works well to foam the cellulose-only mixture (Sample 2) to a stable foam. However, Sample 2 lacks structural support when processing quickly and drying using microwave. The foam ultimately left a flat, fibrous matrix on the substrate. The resulting element was very weak and provided no structural support.

[0120] The mixture of cellulose and starch (Sample 3) allows for quick mechanical mixing to the correct air content. Microwave drying vaporizes the water fast, maintain the structure formed by the air bubbles in the fibers and allows for the gelatinization of the starch. This results in a thick, lightweight, and strong element after drying.Example 4

[0121] Samples were prepared with a formulation comprised of the following, 14.5 wt. % wood fibers, 8.5 wt. % starch, 75.5 wt. % water, and 2.5 wt. % additives, resulting in a foam with a total dry solids content of 24 %. Approximately 0.8 grams of wet foam was applied to a paper substrate. The foam was covered with a release, liner and compressed to 10 mm height. Each sample was then either microwaved dry to completion, placed in a convection oven at 350° F to dry or left at ambient conditions to dry. Weights were taken every 30 second for microwave heated samples and every 2 minutes for convection heated samples. The samples were thentested with a texture analyzer (TAXTplusC, Stable Micro Systems) to determine the maximum stress of the samples. The test method used was derived from ASTM D1621, ASTM D3574, and ASTM DI 596. The method employed herein used the probe on the texture analyzer to measure the initial height of the sample. The machine then compressed the sample to 75% of that initial height, five times in series at a rate of 2 millimeters per second. The force the sample exerted on the probe was recorded. The maximum stress was then calculated by dividing the force at the peak by the area of the sample. The initial (first cycle) maximum stress and the fifth cycle maximum stress results are shown in Table 6.TABLE 6

[0122] The microwaved sample exhibits the lowest density and highest compression strength of the drying methods noted. Additionally, it requires the least amount of time to reach that state, making dielectric heating a good choice for a production scale. The increase in strength can be attributed to the complete gelatinization of the starch within the samples and the rapid heating method.Example 5

[0123] This example demonstrates the difference between using a wet binder compared to a dry powder binder. Compositions were created using 10 % fiber content and either a dry starch binder or a wet PVOH (poly (vinyl alcohol)) solution at 17 % solids. When a formulation was created with > 18 wt. % PVOH solution, the solution became too tacky and wouldn't foam properly. However, at this level, the total solids are still quite low and would have a higher energy requirement to dry.

[0124] Using a dry, ungelatinized starch, allows to the total solids to be increased greatly as the starch has a solids content of 88 - 92 %. Adding 18 wt. % starch to the formulation increases the total solids to approximately 32 % in a 10 % fiber formulation. The starch is ungelatinized during the mixing state so foaming occurs quite rapidly. The resulting foam is not tacky in nature. The resulting dry element made with 18 wt. % wet PVOH had a density of approximately 80 g / L. The resulting dry element made with 18 wt. % dry starch had a density of approximately 55 g / L. The element made with starch had much higher compressive strength, as evidenced by both the initial and 5thcycle maximum stress data shown in Table 7.TABLE 7Example 6

[0125] This example demonstrates the effect of different starch ranges. Samples 1-4 shown in Table 8 were prepared.TABLE S* Sample 4 did not form a foam but rather formed a paste with a dough like consistency.

[0126] The composition and processes described herein work well with starch content up to about 35 wt. %. Beyond that point (e.g., Sample 4) the cycle / mix times may become much greater due to high viscosity, and the foam may not incorporate the same amount of air as adesired. This leaves a dense and heavy foam material which is not commercially viable for the intended markets. See FIG. 7.

[0127] For compositions containing about 7 to about 30% starch, the foam incorporates the desired air content quickly, resulting in the reduction of mix times by nearly 67 %. Synergistically, the solids also are increased substantially in this range compared to typical cellulose-only foams, lowering the drying requirement for the material. The resulting elements are lightweight and strong in nature, making it good candidate for paper packaging systems.

[0128] Compositions containing less than about 7 % starch by weight have very low process times but don't significantly change the solid content compared to cellulose foams alone. These structures are lightweight in nature and may provide minimal protection in paper packaging systems.All patents and publications cited herein are incorporated by reference in their entirety.

Claims

WHAT IS CLAIMED IS:

1. A foamable composition comprising:(a) cellulose fibers;(b) a non-gelatinized starch;(c) a foaming agent;(d) water; and(e) optionally, an additive.

2. The foamable composition of claim 1, comprising:(a) about 5 wt. % to about 25 wt. % cellulose fibers;(b) about 5 wt. % to about 35 wt. % non-gelatinized starch;(c) about 0.1 wt. % to about 5 wt. % foaming agent;(d) about 40 wt. % to about 90 wt. % water; and(e) optionally, up to about 20 wt. % additive.

3. The foamable composition of claim 1 or claim 2, comprising:(a) about 10 wt. % to about 20 wt. % cellulose fibers;(b) about 7 wt. % to about 30 wt. % non-gelatinized starch;(c) about 0.75 wt. % to about 2 wt. % foaming agent;(d) about 50 wt. % to about 80 wt. % water; and(e) optionally, up to about 5 wt. % additive.

4. The foamable composition of any one of claims 1-3, wherein the cellulose fibers comprise softwood virgin fibers, hardwood virgin fibers, recycled softwood virgin fibers, recycled hardwood virgin fibers, or any combination thereof.

5. The foamable composition of any one of claims 1-3, wherein the cellulose fibers comprise kraft pulp fibers.

6. The foamable composition of any one of claims 1-5, wherein the non-gelatinized starch is selected from the group consisting of non-gelatinized potato starch, non-gelatinized wheat starch, non-gelatinized corn starch, non-gelatinized tapioca starch, non-gelatinized rice starch, or any combination thereof.

7. The foamable composition of any one of claims 1-6, wherein the foaming agent is an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or any combination thereof.

8. The foamable composition of claim 7, wherein the surfactant is selected sodium dodecyl sulfate, sodium dioctyl sulfosuccinate, dodecyldimethylamine oxide, stearyl alcohol, glyceryl laurate, polysorbate, cetostearyl alcohol, starch, sucrose, hexadecyl palmitate, lauryl dimethylamine oxide (LDAO), coamidopropyl betaine (CAPB), ethanolamine, sorbitol, disodium dihydrogen ethylene diaminetetraacetate, sulfosuccinates, or any combination thereof.

9. The foamable composition of any one of claims 1-8, wherein the additive is selected from anti-fungal agents, preservatives, biocides, plasticizers, tackifiers, salts, starches, unexpanded microspheres, expanded microspheres, calcium carbonate, clay, nanocellulose, nanocrystalline cellulose, UV dyes, dyes, pigments, defoamers, humectants, waxes, phasechange materials, microencapsulated chemicals, plasticizers, tackifiers, adhesion promoters (e.g. EGDA, PEI), crosslinkers, polyether compounds, rheology modifiers, or any combination thereof.

10. A process for preparing a foamed composition comprising(a) preparing a foamable composition comprising(i) cellulose fibers;(ii) a non-gelatinized starch;(iii) a foaming agent;(iv) water; and(v) optionally, an additive;(b) incorporating air into the foamable composition at a temperature less than about 60° C;(c) optionally, applying the foamable composition onto a substrate; and(d) removing water and gelatinizing the starch in the foamable composition to form the foamed composition.

11. The process of claim 10, wherein step (d) comprises dielectric heating.

12. The process of claim 10 or claim 11, wherein the foamable composition comprises:(a) about 5 wt. % to about 25 wt. % cellulose fibers;(b) about 5 wt. % to about 35 wt. % non-gelatinized starch;(c) about 0.1 wt. % to about 5 wt. % foaming agent;(d) about 40 wt. % to about 90 wt. % water; and(e) optionally, up to about 20 wt. % additive.

13. The process of any one of claims 10-12, wherein the foamable composition comprises:(a) about 10 wt. % to about 20 wt. % cellulose fibers;(b) about 7 wt. % to about 30 wt. % non-gelatinized starch;(c) about 0.75 wt. % to about 2 wt. % foaming agent;(d) about 50 wt. % to about 80 wt. % water; and(e) optionally, up to about 5 wt. % additive.

14. The process of any one of claims 10-13, wherein, wherein the cellulose fibers comprise softwood virgin fibers, hardwood virgin fibers, recycled softwood virgin fibers, recycled hardwood virgin fibers, or any combination thereof.

15. The process of any one of claims 10-14, wherein the cellulose fibers comprise kraft pulp fibers.

16. The process of any one of claims 10-15, wherein the non-gelatinized starch is selected from the group consisting of non-gelatinized potato starch, non-gelatinized wheat starch, non-gelatinized corn starch, non-gelatinized tapioca starch, non-gelatinized rice starch, or any combination thereof.

17. The process of any one of claims 10-16, wherein the foaming agent is an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or any combination thereof.

18. The process of claim 17, wherein the surfactant is sodium dodecyl sulfate, sodium dioctyl sulfosuccinate, dodecyldimethylamine oxide, stearyl alcohol, glyceryl laurate, polysorbate, cetostearyl alcohol, starch, sucrose, hexadecyl palmitate, lauryl dimethylamine oxide (LDAO), coamidopropyl betaine (CAPB), ethanolamine, sorbitol, disodium dihydrogen ethylene diaminetetraacetate, sulfosuccinates, or any combination thereof.

19. The process of any one of claims 10-18, wherein the additive is selected from anti-fungal agents, preservatives, biocides, plasticizers, tackifiers, salts, starches, unexpanded microspheres, expanded microspheres, calcium carbonate, clay, nanocellulose, nanocrystalline cellulose, UV dyes, dyes, pigments, defoamers, humectants, waxes, phase-change materials, microencapsulated chemicals, plasticizers, tackifiers, adhesion promoters (e g. EGDA, PEI), crosslinkers, polyether compounds, rheology modifiers, and any combination thereof.

20. An article comprising:(a) a foamed composition comprising:(i) cellulose fibers;(ii) a gelatinized starch;(iii) a foaming agent;(iv) a plurality of air pockets; and(v) optionally, an additive.

21. The article of claim 20, further comprising (b) one or more substrates.

22. The article of claim 21, wherein the one or more substrates is, independently, a cellulosic substrate, a metal substrate, a plastic substrate, or any combination thereof.

23. The article of claim 21 or claim 22, wherein the one or more substrates is, independently, paper, a corrugate, a compostable polymer film, a biodegradable polymer film, a biobased film, cellophane, a polyester film, a polypropylene film, a polyethylene film, a metalized film, a recyclable paper, a recycled paper, a recyclable coated paper, a recyclable metal vapor deposited paper, or any combination thereof.

24. The article of any one of claims 20-23, where the article is in the form of an envelope, a pouch, a bag, a box, a carton, a case, a lid, a wrap, a clamshell, a cup, a flat thermally insulating sheet, a molded three-dimensional package element, a folded package element, or a food container with adhesive.

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