Biodegradable biological foams

Abstract

The present invention relates to biodegradable biofoams and methods of making biodegradable biofoams, such as the claimed biofoams. The foams provide a product comprising organic materials that can be naturally broken down in compost or soil, or can be used for bioenergy. The present invention eliminates or reduces any dependence on fossil fuels and provides a biofoam that is completely free of petrochemicals. The biofoam can be made almost entirely from plant-based and / or renewable materials. The biofoam can comprise green fillers, additives, and structural components to replace petrochemical compounds.

Description

Technical Field

[0001] The present invention relates to biodegradable biofoam, a method for producing the biodegradable biofoam, and an object comprising the biodegradable biofoam. Background Technology

[0002] The foam materials industry is a large and crucial sector with wide-ranging applications, facing significant environmental challenges. These challenges stem from the environmental impact of foam material production, waste management issues, and the urgent need to transition to more sustainable alternatives.

[0003] Globally, the production of furniture foam materials alone generates 105 million tons of CO2 emissions annually. A significant portion of these emissions is due to the heavy reliance on petroleum in their production. Specifically, global polyurethane foam production totals 26 million tons, with the majority (90-88%) derived from petrochemical products. While petrochemical products constitute only a small fraction of crude oil, their demand largely sustains fossil fuel consumption.

[0004] The production of petrochemical products heavily relies on fossil fuels, which serve as both raw materials and energy sources in materials manufacturing. Therefore, the International Energy Agency emphasizes that petrochemical products could become a significant driver of oil demand growth within the next decade. To achieve the goal of limiting global warming to 1.5°C, a substantial portion of fossil fuel reserves must remain unexploited. For example, an average armchair emits 43 kg of CO2, nearly half of which is attributed to furniture foam. This demonstrates that the foam industry needs to find alternative methods to reduce its reliance on petrochemical products and mitigate its negative environmental impact.

[0005] US2022 / 0185978A1 describes a biodegradable foam material composed of a cellulose ester polymer, a polyglycerol ester plasticizer, and CaCO3, chitosan, or chitin as a nucleating agent, forming a closed-cell foam suitable for packaging applications. CN101003646A discloses a method for manufacturing low-cost starch-based foamable biomaterials and bio-foam products by processing a mixture of starch, a thermoplastic polymer, a nucleating agent, water, additives, and a blowing agent in a preheated screw extruder. US2022 / 0162413A1 describes a method for manufacturing expanded rigid foam with sealed pores, comprising mixing an anionic polymer, a blowing agent, a polyvalent cation, and a solvent, stirring to form a foam, adding a proton-releasing compound for gelation, and drying to obtain a foam with sealed pores. Expanded rigid foam can be used in packaging, garden containers, decorations, insulation materials, and other applications. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide alternative foam materials that do not contain petrochemical products and a method for sustainably manufacturing such foam materials.

[0007] This invention relates to biodegradable biofoam, methods for manufacturing the foam, and novel uses of the foam, as described in the patent claims and detailed description.

[0008] On one hand, the present invention relates to biodegradable biofoam, comprising: Biodegradable biofoam, comprising: At least 80% by weight of bio-based materials and / or renewable materials, wherein The bio-based materials and / or renewable materials include At least one structural component, wherein the at least one structural component is a hydrocolloid; and Up to 20% by weight of bio-derived inorganic compounds, Optional one or more additives, wherein the additives contain green filler. This invention provides a bio-foam product comprising at least 80% bio-based and / or renewable materials, with the remainder comprising bio-derived inorganic compounds. This distinguishes the invention from industrial polyurethane foams, which heavily rely on petrochemical products. 60% to 80% of the raw materials used in various aspects of this invention are derived from the ocean, with a focus on sustainable development and efforts to protect ecosystems. This biodegradable bio-foam includes organic materials that can decompose naturally in compost or soil, or can be used for bioenergy. This invention eliminates or reduces any dependence on fossil fuels and provides a completely petrochemical-free bio-foam. On the other hand, the present invention relates to a method for producing biodegradable biofoam (e.g., the claimed biofoam), wherein the method comprises at least the following steps: A. Preparing a structural polymer-solvent mixture by mixing at least one structural component and a solvent; B. Pre-foamed mixtures are prepared by mixing the structural polymer-solvent mixture with at least one additive; C. Heat the pre-foamed mixture and / or the structural polymer-solvent mixture to a temperature range of 30-70°C; D. A foamed mixture is prepared by adding a foaming agent, a foam stabilizer, and / or applying mechanical stirring to induce mechanical and / or chemical foaming in the pre-foamed mixture; E. A gel mixture is prepared by providing at least one gel initiator to the foaming mixture; F. Set the foam in a mold; G. Dry the foam; wherein Step AF includes a wet phase, and step G includes a dry phase.

[0009] The bio-foam of this invention can preferably be handcrafted in a sustainable production facility. The bio-foam of this invention can also be manufactured by machine. Compared to conventional foam production methods, this invention can reduce the carbon footprint from cradle to gate by at least 30%.

[0010] The production method of this invention is divided into a wet stage and a dry stage, which can recover 40% of the wastewater and then reintegrate it into our production cycle, thereby minimizing waste. More than 90% of the energy used in the method of this invention comes from renewable energy sources, which underscores our commitment to sustainable development.

[0011] This invention provides foams that can be used, for example, in furniture padding, shoe insoles, sound insulation materials, seat padding, headphone padding, microphone padding, and other applications that typically use flexible polyurethane. In some aspects, this invention relates to objects comprising biodegradable bio-foams selected from the group consisting of furniture padding, shoe insoles, sound insulation materials, seat padding, headphone padding, and microphone padding. Therefore, this novel bio-foam can replace polyurethane or other petrochemical-based materials.

[0012] This invention provides materials that can be modified or customized to exhibit specific properties. Depending on the customer's preference, these materials can be flexible foam materials similar to polyurethane or rigid materials similar to isoprene.

[0013] This invention includes two variants of the biofoam: open-cell and closed-cell. Detailed Implementation

[0014] Unless otherwise defined, all technical terms, symbols, and other scientific terms used herein are intended to have the meaning commonly understood by one of ordinary skill in the art to which this invention pertains. In some cases, for clarity and / or convenience of reference, terms with a generally understood meaning are defined herein, and these definitions should not necessarily be construed as materially different from their generally understood meaning in the art.

[0015] This invention relates to biodegradable biofoam and methods for producing said foam.

[0016] This biodegradable biofoam is at least partially a bio-based material, meaning it is a material containing biological and / or renewable resources, rather than a material made from petroleum or fossil resources. Biological or renewable resources are typically plants or animals, preferably from marine plants or marine animals. In some respects, the biodegradable biofoam may be a molded foam.

[0017] In some respects, biodegradable biofoams contain at least 80% by weight of bio-based materials and / or renewable materials, such as 85%, 90%, 95%, or 98% by weight.

[0018] This biodegradable biofoam is biodegradable, meaning it can at least partially decompose naturally in compost or soil, or it can be used for bioenergy. Therefore, the biofoam can decompose naturally through natural processes, particularly through the action of living microorganisms such as bacteria and fungi. Because of the biodegradable nature of the biofoam disclosed herein, essential nutrients can be returned to the environment, or degradation products can be converted into bioenergy.

[0019] Foam materials are a class of materials comprising porous structures, which include air-filled cavities or bubbles embedded in a solid matrix, wherein the solid matrix defines the pores. These air-filled pores can be open or interconnected, thus forming open-cell foam. Alternatively, the air-filled pores can be closed or isolated, thus forming closed-cell foam. Therefore, as used herein, foam or biofoam refers to materials comprising porous structures having voids or air-filled pores dispersed in a solid matrix, thus forming lightweight porous materials. Depending on the structure of the air-filled pores, foam materials can have different properties. Compared to closed-cell foam, open-cell foam contains more air, which is reflected in the foam's stiffness. Open-cell foam is more compressible than closed-cell foam.

[0020] The solid matrix of a biofoam defines the walls of the pores. This invention relates to biodegradable biofoams, a type of polymer-based foam, and more specifically, a biopolymer-based foam. The solid matrix is ​​typically made from a structural polymer through a process called gelation. Gelation refers to the process by which a liquid solution containing a structural polymer transforms into a semi-solid or solid state, forming a network structure. Structural polymers have long-chain molecules with repeating units and typically contain side groups or functional groups on their main chain or side chains. Due to their high molecular weight and chain-like structure, multiple interaction points exist between the polymer chains in solution. Crosslinking of the structural polymer leads to the formation of the polymer matrix. Therefore, the molecular structure of such polymers influences gelation and network formation.

[0021] The disclosed biodegradable biofoam comprises at least one structural component, such as a structural polymer, wherein the at least one structural polymer is a hydrocolloid. In the biofoam described herein, the structural polymer is a bio-based material and / or derived from renewable materials. The hydrocolloid is a water-soluble polymer that, when dispersed in water, can form a viscous dispersion or gel. Hydrocolloids can alter the texture of an aqueous system and provide stability. The at least one hydrocolloid can be various types of hydrocolloids, such as bio-hydrocolloids, synthetic hydrocolloids, and semi-synthetic hydrocolloids. Preferably, the at least one hydrocolloid is derived from a biological source, such as a plant source, an animal source, or a microbial source. Plant sources may include algae such as macroalgae. Non-limiting examples of macroalgae include red algae (Rhodyphyta), brown algae (Phaeophyta), and green algae (Chlorophyta). The algae can be wet or dry. Animal sources may include crustaceans, fish, and terrestrial animals. Non-limiting examples of crustaceans include shellfish such as shrimp, crab, and krill. Therefore, in all respects, at least one hydrocolloid is selected from agar, carrageenan, cellulose, cellulose nanofibers, chitosan, chitin, pectin, guar gum, xanthan gum, wet seaweed, dry seaweed and gelatin.

[0022] During extensive testing, the applicant found that crosslinking more than one type of structural polymer with each other was a significant challenge, and often impossible, leading to material collapse and rendering it unusable as a foam material.

[0023] In some aspects, biofoams contain at least one structural polymer, such as one structural polymer, two structural polymers, or three structural polymers. At least one structural polymer may be suitable for crosslinking with other structural polymers of the biofoam material, i.e., crosslinking with structural polymers of the same type and / or different types, and maintaining a stable polymer matrix over time. In some aspects, at least one structural polymer may be a hydrocolloid selected from the group consisting of: alginate, gelatin, chitin, chitosan, carrageenan, pectin, guar gum, xanthan gum, fucoidan, agar, cellulose derivatives, cellulose, and cellulose nanofibers. If the biofoam contains more than one structural polymer, the different structural polymers are generally chemically compatible, capable of forming strong chemical bonds with each other, have similar thermal stability, and are compatible with other additives in the biofoam.

[0024] The applicant has invested significant effort in product development to identify combinations of different structural polymers capable of forming a stable cross-linked polymer matrix. By combining different types of structural polymers, biofoam properties different from those obtained using only one structural polymer can be achieved.

[0025] In some aspects, at least one structural polymer may comprise an alginate and one or more structural polymers selected from gelatin, chitin, chitosan, carrageenan, pectin, guar gum, xanthan gum, fucoidan, agar, cellulose derivatives, cellulose, and cellulose nanofibers. Preferably, at least one structural polymer comprises an alginate and one or more structural polymers selected from gelatin, chitin, chitosan, and guar gum.

[0026] The biofoam may also contain two structural polymers, namely alginate and gelatin, or alginate and chitin, or alginate and chitosan, or alginate and cellulose, or alginate and cellulose nanofibers.

[0027] Biofoams can also contain more than two structural polymers, such as alginate, gelatin and chitin, or alginate, gelatin and chitosan.

[0028] The choice of at least one structural polymer can affect the properties of biofoam, including mechanical strength, density, flexibility and elasticity, compressibility and thermal properties.

[0029] The applicant discovered that biofoam variants containing two structural polymers, alginate and gelatin, produce thicker, stronger, and more compressible foams compared to biofoams containing only an alginate structural polymer. This effect was observed in both closed-cell and open-cell biofoams, likely due to the way the two structural polymers organize the polymer matrix. Biofoam variants containing two structural polymers, alginate and chitin or alginate and chitosan, produced more porous and more inflatable foam structures compared to other biofoam variants. Surprisingly, biofoams containing two structural polymers, alginate and chitin or alginate and chitosan, exhibited viscoelasticity very similar to memory foam. Another biofoam variant, comprising three structural polymers—alginate, gelatin, and chitin—is an inflatable foam with superior foaming properties, resulting in increased biofoam thickness.

[0030] At least one structural polymer can be used in its native form or in its salt form. The salt form typically consists of an organic polymer backbone containing acidic or basic functional groups and a counterion that neutralizes these groups. Examples of such counterions include sodium, calcium, and potassium. Therefore, at least one structural polymer can exist in its salt form, preferably an alginate, which comprises sodium alginate (Na-alginate), calcium alginate (Ca-alginate), or potassium alginate (K-alginate). At least one structural polymer can exist in its native form and be converted in situ to its salt form. For example, alginate and sodium hydroxide can be used in combination to form sodium alginate in situ. The content of at least one structural polymer is sufficient to gel the at least one structural polymer and form a structural matrix. If the content of at least one structural polymer is too high, the biofoam may become too rigid and dense, thereby impairing its ability to foam effectively and ultimately forming a rigid, inflexible material, i.e., a material lacking characteristic foam properties. In some aspects, the biofoam may include alginate as at least one structural component, in an amount of 50-95% by weight of the biofoam, for example, typically 50-65% by weight, for example 65-95% by weight, more preferably 60-90% by weight. In some aspects, at least one structural component of the biofoam comprises alginate and gelatin, or alginate and chitin, or alginate and chitosan. The biofoam may contain at least one structural component in a ratio of 2:1 to 1:2, for example 2:1, 1:1, or 1:2. In some aspects, at least one structural component of the biofoam comprises alginate, chitin, and gelatin. The ratio of each structural component can be from 1:1:1 to 3:1:3, for example, 1:1:1, 2:1:2, 2:1:3, 3:1:2, or 3:1:3. The amount of each structural component can be varied depending on the desired performance of the bio-foam.

[0031] In some respects, biodegradable biofoams contain up to 20% by weight of bio-derived inorganic compounds, such as 0-5% by weight, 5-10% by weight, 10-15% by weight, or 15-20% by weight. Inorganic compounds make a variety of contributions to foam materials.

[0032] For example, such inorganic compounds can be used as fillers, stabilizers, reinforcing agents, foaming agents, or blowing agents. In various respects, inorganic compounds are selected from salts, oxides, acids, bases, minerals, and metals. Preferably, the inorganic compounds are bio-derived inorganic compounds selected from minerals, such as CaCO3, CaSO4, SiO2, and Na3PO4. Preferably, the inorganic compounds include bio-derived inorganic compounds, wherein the bio-derived inorganic compounds include minerals from marine and / or terrestrial sources, such as plant and / or animal sources. Marine sources of inorganic compounds are selected from microalgae, marine protozoa, mollusc shells, fish scales and bones, and crustacean shells. Non-limiting examples of such marine sources include diatoms, foraminifera, oysters, clams, mussels, fish waste from the food industry, crabs, and shrimp. Terrestrial sources include sources such as animal bones and eggshells. Preferably, the sources of inorganic compounds are obtained using methods that do not disturb the ecosystem. This means that these raw materials are waste from other industries, such as fish waste from the food industry, but can be further used in foams as disclosed herein. Another example is the use of crab shells recovered from the seabed during seabed cleanup operations. The choice of inorganic source depends on the structural polymer used in the biofoam, as the properties of the inorganic component may be suitable for the structure and properties of the structural polymer. Alternatively, inorganic compounds may include substances from non-biological sources, such as minerals from mining activities. When selecting the source of inorganic compounds, careful consideration should be given to the properties of the biofoam material, its environmental impact, its biodegradability, and its long-term sustainability.

[0033] This biodegradable biofoam may contain at least one additive. Additives comprise a broad class of compounds that, when incorporated into the biopolymer matrix, can enhance, alter, or impart specific properties to the final product. Therefore, the role of the structural polymer in the foam is to form the structural matrix, providing the foundation for the foam material and supporting its overall integrity. Additives can enhance foam stability, regulate mechanical properties, control cell structure, promote nucleation, improve fire resistance, or provide specific functions such as antimicrobial or UV protection. Additives include, but are not limited to, fillers, curing agents, plasticizers, stabilizers, foaming agents, flame retardants, and colorants. Each additive contributes differently to the biofoam. For example, nucleating agents can enhance the formation of small crystals during polymer foaming, promoting bubble formation and thus affecting the foam's porous structure, porosity, and density, thereby influencing the overall microstructure of the foam. In contrast, fillers are chemically inert in biofoam; they alter the foam's properties by physically occupying space within the foam matrix.

[0034] The biodegradable biofoam may contain at least one filler, preferably a biodegradable and / or recyclable green filler. When the filler is incorporated into the polymer matrix, it physically occupies space within the polymer matrix, thereby altering the properties of the biofoam. Therefore, the filler described herein is chemically inert to the biofoam. When used as a filler, the compound does not crosslink with any of the structural polymers of the biofoam. The filler can enhance the mechanical strength, hardness, robustness, thermal conductivity, flexibility, elasticity, compressibility, fire resistance, and aesthetics of the biopolymer-based foam, thus making various contributions to the biopolymer-based foam. For example, the filler can modulate properties such as the hardness and robustness of the biofoam.

[0035] In some aspects, at least one green filler is used as a component of the biofoam. When defining a filler as a green filler, not only is the filler source natural, but at least one green filler is also sustainably sourced, has a minimal carbon footprint, is non-toxic, and is biodegradable and / or recyclable. To obtain ideal foam properties and performance, careful selection and optimization of the filler type, size, concentration, and distribution within the polymer matrix are required. At least one green filler can be an inorganic compound as described above. Alternatively, it can be an organic compound derived from plants, where the plant source can include marine and terrestrial sources. In some aspects, at least one green filler is an inorganic and / or organic compound. In some aspects, at least one green filler is selected from CaCO3, cellulose, and cellulose nanofibers. In some aspects, at least one green filler is selected from CaCO3, cellulose, cellulose nanofibers, chitin, and chitosan. Preferably, at least one filler comprises CaCO3 and cellulose nanofibers. In some aspects, at least one filler comprises CaCO3 and cellulose nanofibers, and also comprises at least one additional biodegradable and / or recyclable filler selected from chitosan and chitin. Preferably, at least one filler is sourced from waste from other industries. In some respects, cellulose nanofibers are waste products from the papermaking process, CaCO3 comes from crab shells or eggshells or mining, while chitosan and chitin come from shrimp shells and / or old crab shells. The type and quantity of filler can be selected based on one or more structural polymers of the biofoam. The size of the filler can be appropriate to fit the polymer matrix of the biofoam, and its content can allow the polymer matrix to maintain its structure, i.e., not collapse. The biofoam may contain CaCO3 as filler, with a content of 0.2-35% by weight, for example, typically 0.2-3% by weight, for example 3-10% by weight, or 10-35% by weight, preferably 0.3-10% by weight. The biofoam may further contain cellulose nanofibers as filler, with a content of 1-80% by weight, for example, typically 1-25% by weight, 25-50% by weight, 50-80% by weight, preferably 5-45% by weight.

[0036] The biodegradable biofoam may contain at least one blowing agent and / or at least one foam stabilizer. These agents are substances that contribute to the formation of a porous structure during a process commonly referred to as the foaming process. The foaming process refers to the formation of a porous structure within a polymer matrix, typically due to the generation and expansion of bubbles. Gases used for foaming can be introduced in various ways, usually using blowing agents and / or foam stabilizers. Blowing agents include chemical blowing agents, which are compounds that decompose upon heating to release gas; and enzymatic blowing agents, which are enzymes that utilize sources within the biopolymer composition to generate gas within the biopolymer matrix, such as yeast or yeast mixtures. Enzymatic blowing agents mentioned herein, specifically those used to convert a substrate into a gaseous product via an enzymatic conversion reaction, are also considered part of the enzymatic blowing agent. For example, yeast containing catalase combined with the desired substrate hydrogen peroxide (H₂O₂) is considered an enzymatic blowing agent. In chemical foaming processes, blowing agents are typically added to the polymer mixture.

[0037] The biofoam may contain at least one foam stabilizer. Foam stabilizers (such as surfactants) do not generate gas themselves, but rather promote and stabilize the foam formed after gas introduction. In some respects, foam stabilizers contain surfactants. Such surfactants can be used in mechanical foaming processes, which employ mechanical methods, including high-speed stirring, agitation, or other methods of incorporating or introducing air or other gases into the biopolymer solution. Surfactants contribute to bubble formation and stabilization. Surfactants can also be used in conjunction with blowing agents in chemical foaming processes. Therefore, the biofoam may include at least one foam stabilizer and at least one blowing agent. The foaming process can also occur without any additives, i.e., by mechanically incorporating air, such as through vigorous stirring, agitation, or agitation. The method of initiating the foaming process depends on the composition of the biofoam, particularly the structural polymer used. Therefore, biodegradable biofoams may not contain blowing agents and / or foam stabilizers.

[0038] The choice of foaming agent or foam stabilizer depends on the desired performance of the final biofoam. Combining a foam stabilizer with mechanical foaming can produce a closed-cell foam, wherein the pores within the biopolymer matrix are closed and tightly packed together. This biodegradable biofoam may include a closed-cell foam containing at least one foam stabilizer, which in turn contains at least one surfactant. Preferably, the at least one surfactant is selected from saponins, alkyl polysaccharides, sucrose esters, and sorbitol esters. Preferably, the foam stabilizer is derived from renewable resources.

[0039] Foaming agents and / or foam stabilizers and / or mechanical foaming can produce open-cell foams, in which the pores within a biopolymer matrix are interconnected, thereby forming a more flexible and compressible material. In some respects, biodegradable biofoams are open-cell foams containing at least one foaming agent, such as at least one chemical foaming agent and / or at least one enzymatic foaming agent. Preferably, the at least one enzymatic foaming agent is selected from catalase, glucose oxidase, and α-amylase, and also includes a corresponding substrate for each enzyme. Preferably, the at least one enzymatic foaming agent contains catalase and also contains a substrate for catalase, namely hydrogen peroxide (H₂O₂). In some cases, closed-cell foams can be converted into open-cell foams by applying mechanical force to them. In some aspects, mechanical forces such as kneading can be used to convert closed-cell foams into open-cell foams.

[0040] In some respects, biodegradable biofoams contain at least one plasticizer. Plasticizers are a class of additives that help modify or improve the properties of foam materials, including their flexibility, softness, compressibility, and resilience. Plasticizers are typically small-molecule or low-molecular-weight compounds because these molecules can interweave with polymer chains, reducing intermolecular forces and allowing the polymer chains to move more freely. Increased polymer chain fluidity results in greater flexibility and better processability. In some respects, plasticizers may be foaming agents. In others, plasticizers may be polyols, such as sugars or larger alcohols. Preferably, the plasticizer is glycerol, also known as glycerol or glyceryl alcohol. The choice of plasticizer depends on the structural polymer used, processing requirements, and end use.

[0041] This invention includes compositions providing closed-cell foams in various aspects and compositions providing open-cell foams in various aspects. This invention also includes methods for manufacturing closed-cell and open-cell biofoams.

[0042] The selection of at least one foaming agent or foam stabilizer depends on the desired performance of the final product. Combining a foam stabilizer with mechanical foaming can produce closed-cell foam, where the pores within the biopolymer matrix are closed and tightly packed together. Foaming agents and / or foam stabilizers and / or mechanical foaming can produce open-cell foam, where the pores within the biopolymer matrix are interconnected, thereby forming a more flexible and compressible material. In some aspects, biodegradable biofoams contain at least one foaming agent, such as a foam stabilizer. In some aspects, biodegradable biofoams contain at least one foaming agent, such as a foam stabilizer, and / or at least one enzymatic foaming agent. Preferably, at least one foam stabilizer is a surfactant; more preferably, the surfactant is a green surfactant derived from a renewable resource selected from saponins, alkyl polysaccharides, sucrose esters, or sorbitan esters. Preferably, at least one enzymatic foaming agent is selected from catalase, glucose oxidase, and α-amylase, and also includes a corresponding substrate for each enzyme. In some cases, closed-cell foam can be converted into open-cell foam by applying mechanical force to it. In some respects, mechanical forces such as kneading can be used to convert closed-cell foam into open-cell foam.

[0043] The biodegradable biofoam may contain at least one additive in the form of a chelating agent. A chelating agent (sequestering agent, chelator, or chelating agent) can form multiple coordination bonds with a single metal ion. Therefore, they are able to chelate metal ions, preventing these ions from participating in unwanted premature reactions or processes. The choice of chelating agent depends largely on the choice of the biopolymer used as a structural component. The chelating agent may possess suitable properties to effectively bind to metal ions present in the aqueous biopolymer solution and form complexes. Other variables that may be considered when selecting a chelating agent include, but are not limited to: the metal ion to be chelated, pH sensitivity, desired foam characteristics, and the desired release mechanism of the chelated ions. In some respects, at least one chelating agent is selected from trisodium phosphate (Na3PO4), disodium hydrogen phosphate (Na2HPO4), sodium citrate (Na3C6H5O7), and tetrasodium pyrophosphate (Na4P2O7).

[0044] The biodegradable biofoam disclosed in this invention may include at least one gel initiator, also commonly referred to as a gelling agent. Herein, a gel initiator is defined as a method for transforming a foam from a liquid or semi-liquid state into a solid state while ensuring that the foam retains its desired porous structure and mechanical properties. The primary function of a gel initiator is to promote the crosslinking or bonding of polymer chains, thereby forming a three-dimensional network structure within a polymer matrix. Thus, the gel initiator promotes the crosslinking of the structural components (i.e., the structural biopolymers of the biofoam). The formation of the solid matrix subsequently imparts the foam structure. The gelation reaction provides the foam material with the desired rigidity and structure, enabling it to possess the desired properties. The choice of gel initiator depends on the type of structural biopolymer used, as the properties of the gel initiator may be suitable for interacting with the biopolymer to provide a stable foam structure. In various respects, a gel initiator includes a substance, a gel initiation step, and / or a gel initiation action. In some respects, at least one gel initiator is a substance selected from cationic, anionic, and organic acid groups. In some respects, at least one gel initiator is selected from potassium ions (K+). + ), calcium ions (Ca 2+ ), magnesium ions (Mg 2+ ), aluminum ions (Al) 3+ The gel initiator comprises tripolyphosphate (TPP) and acetic acid. Preferably, at least one gel initiator comprises a divalent cation. Preferably, at least one gel initiator is selected from calcium sulfate (CaSO4), calcium carbonate (CaCO3), and calcium chloride (CaCl2).

[0045] In some respects, biodegradable biofoams do not contain gel initiators. Gelation initiation methods may include a gelation initiation step (e.g., temperature regulation) or incubation at a specific temperature for a specific time. For temperature-dependent gelation, a change in temperature, rather than the addition of a gel initiator, drives the structured polymer solution from a liquid phase to a gel or solid phase. Temperature-dependent gelation can be classified as positive temperature-dependent gelation and negative temperature-dependent gelation, reflecting that increasing and decreasing temperature, respectively, promotes gelation. Whether an increase or decrease in temperature promotes gelation depends on the structured polymer and other components in the polymer mixture.

[0046] Therefore, various variants of biodegradable biofoam can be modified by changing the ratio of bio-based and / or renewable materials to inorganic compounds. In some respects, the ratio of bio-based and / or renewable materials to inorganic compounds may be in the range of 100:1 to 4:1, such as 9:1, 19:1, or 30:1.

[0047] For example, a variant of the biodegradable biofoam of the present invention may include alginate as a structural component, inorganic CaCO3 from old crab shells as a filler, and cellulose nanofibers as a green filler. Another variant of the biodegradable biofoam may include alginate and gelatin as structural components, and inorganic CaCO3 from eggshells as a filler.

[0048] In some aspects, the biodegradable biofoam may include an alginate selected from alginate, alginic acid, sodium alginate, calcium alginate, and potassium alginate as at least one structural component, and at least one biodegradable and / or recyclable filler comprising CaCO3 and cellulose nanofibers. The alginate comprises 50-95% by weight, calcium carbonate 0.2-31% by weight, and cellulose nanofibers 1-80% by weight. In some aspects, the biofoam is a soft foam comprising at least one structural component of 50-65% by weight alginate, and at least one biodegradable and / or recyclable filler comprising 0.2-3% by weight CaCO3 and 1-25% by weight cellulose nanofibers. This biofoam variant is suitable for surfaces that bear slight weight, such as sandwich structures. In some respects, this biofoam is a relatively rigid foam comprising at least one structural component of 50-65% by weight alginate and at least one biodegradable and / or recyclable filler comprising 0.2-3% by weight CaCO3 and 25-50% by weight cellulose nanofibers. This is an example of a biofoam variant capable of withstanding weights up to 100 kg, such as 80 kg or 50 kg. Therefore, this biofoam variant is suitable as part of a structure required to support a weight of 100 kg, such as 80 kg or 50 kg. Preferably, the biofoam comprises at least one structural component, which is 60-90% by weight of alginate, and at least one biodegradable and / or recyclable filler comprising 0.3-1% by weight of calcium carbonate and 5-45% by weight of cellulose nanofibers.

[0049] In some respects, biodegradable biofoams contain alginate and chitin and / or gelatin as structural polymers, and calcium carbonate and cellulose nanofibers as fillers.

[0050] On the other hand, the present invention relates to a method for producing biodegradable biofoam according to the first aspect, such as the biodegradable biofoam disclosed herein, wherein the method includes a wet process stage and a dry process stage. The applicant has developed a method for producing biodegradable biofoam in which the production process can recover 40% of the wastewater and subsequently reintegrate it into the production cycle. This is achieved through a process comprising wet and dry phases. During the dehumidification process of the biofoam transitioning from the wet phase to the dry phase, the collected water can be reused in subsequent production processes. Therefore, this production process can significantly reduce total water consumption and wastewater volume. Furthermore, the production process follows sustainable development principles, with over 90% of the energy used in the production process derived from renewable resources.

[0051] This invention provides, in some respects, a method for producing biodegradable biofoam, the method comprising at least the following steps: A. Preparing a structural polymer-solvent mixture by mixing at least one structural component and a solvent; B. Pre-foamed mixtures are prepared by mixing a structural polymer-solvent mixture with at least one additive; C. Heat the pre-foamed mixture and / or the structural polymer-solvent mixture to a temperature range of 30-70°C; D. A foamed mixture is prepared by inducing mechanical and / or chemical foaming by adding a foaming agent, a foam stabilizer, and / or mechanical stirring to the pre-foamed mixture; E. A gel mixture is prepared by providing at least one gel initiator to the foaming mixture; F. Shape the foam material in a mold; G. Dry the foam; wherein Step AF includes a wet phase, and step G includes a dry phase.

[0052] The above methods can be detailed below. The definition of biological foam is as described in the first aspect.

[0053] Examples 1 and 2 provide examples of specific concentrations used for each component in the production of the closed-cell and open-cell foams described herein. Specific quantities are merely illustrative and may vary. Those skilled in the art will recognize that the specific amounts of the compounds described herein can be adjusted according to the desired characteristics or performance of the final product (i.e., the biodegradable biofoam). Such fine-tuning of component amounts should be within the capabilities of those skilled in the art to optimize the method and achieve the desired specifications.

[0054] First, at least one structural component (wherein at least one structural component is a structural polymer) is mixed with a solvent to prepare the structural polymer-solvent mixture of step A. The at least one structural component comprises a hydrocolloid. In some aspects, the structural polymer-solvent mixture is mixed until homogeneous. In some aspects, the structural polymer-solvent mixture is not homogeneously mixed, i.e., the structural polymer is not uniformly dispersed in the solvent. As described above in the application, the structural polymer can be in its natural form or salt form. In some aspects, the at least one structural polymer is selected from alginate, gelatin, chitin, chitosan, carrageenan, pectin, guar gum, xanthan gum, fucoidan, agar, cellulose, cellulose derivatives, and cellulose nanofibers. In some aspects, the at least one structural polymer is an alginate, selected from alginic acid, alginate, sodium alginate, calcium alginate, and potassium alginate. In some aspects, the at least one structural polymer is an alginate in salt form, preferably sodium alginate. In some aspects, at least one structural polymer is an alginate, and at least one additional structural polymer is selected from gelatin, chitin, chitosan, carrageenan, pectin, guar gum, xanthan gum, fucoidan, agar, cellulose, cellulose derivatives, and cellulose nanofibers, preferably gelatin, chitin, chitosan, and guar gum. In some aspects, at least one structural polymer is alginate and gelatin, or alginate and chitin, or alginate and chitosan, or alginate and cellulose, or alginate and cellulose nanofibers. In aspects where more than one structural component is added, at least one structural component in the structural polymer-solvent mixture is selected from alginate, sodium alginate, potassium alginate, calcium alginate, and alginic acid. The solvent used in step A can be a suitable dispersion or dissolution medium for at least one structural polymer, thereby uniformly forming a solution or gel, which can then be foamed. The at least one structural polymer of the present invention is a biopolymer, preferably a hydrocolloid polymer. Since hydrocolloids are water-soluble polymers, the solvent is preferably a polar or hydrophilic solvent. In some aspects, the solvent is selected from water, glycerol, and ethanol, with water being the preferred solvent. Optionally, means are provided to heat the structural polymer-solvent mixture to better dissolve the structural polymer in the solvent. In some aspects, the solvent is preheated to a temperature range of 30-70°C, for example, 30-50°C, 50-70°C, preferably 35-65°C. In some aspects, the temperature range is 30-100°C, for example, 35-65°C, or 65-100°C. In some aspects, when the at least one structural polymer contains alginate, the temperature range is 30-70°C to sufficiently dissolve the alginate. In some aspects, when at least one structural polymer comprises alginate and gelatin, the temperature range is 30-100°C, for example 65-100°C. In some aspects, at least one structural polymer is added to a preheated solvent and mixed.

[0055] Next, the structural polymer-solvent mixture from step A is mixed with at least one additive (e.g., at least one filler, chelating agent, and / or plasticizer) to prepare the pre-foamed mixture from step B. Such additives are added to the pre-foamed mixture containing the basic structural polymer to modify the properties or processing characteristics of the pre-foamed mixture. The function of each additive has been described in detail in the foregoing sections of this invention. In some aspects, the at least one additive added to the structural polymer-solvent mixture for preparing the pre-foamed mixture comprises at least one plasticizer (e.g., glycerol), at least one filler (e.g., at least one filler selected from CaCO3, cellulose nanofibers, chitosan, and chitin), and / or at least one chelating agent (e.g., Na3PO4). In some aspects, the at least one additive comprises at least one biodegradable and / or recyclable filler selected from CaCO3 and cellulose nanofibers. In some aspects, the at least one additive comprises at least two biodegradable and / or recyclable fillers comprising CaCO3 and cellulose nanofibers. In some aspects, the at least one biodegradable and / or recyclable filler comprises CaCO3, cellulose nanofibers, and chitosan and / or chitin.

[0056] Optionally, at least one additional structural component may be added to the pre-foamed mixture. The at least one additional structural component is selected from agar, carrageenan, cellulose, cellulose nanofibers, pectin, guar gum, xanthan gum, gelatin, chitin, chitosan, and fucoidan, preferably gelatin, chitin, chitosan, cellulose, cellulose nanofibers, and guar gum. In some aspects, when at least one structural polymer in the structural polymer-solvent mixture comprises alginate, the at least one additional structural polymer added to the pre-foamed mixture comprises gelatin and chitin, or gelatin and chitosan.

[0057] Optionally, at least one chelating agent and / or plasticizer may be added to the mixture in step B to modify the properties or processing characteristics of the pre-foamed mixture. The selection of the components and their amounts depend on the desired properties of the final biofoam product. In some aspects, at least one plasticizer containing glycerol is added in step B. In other aspects, at least one plasticizer containing glycerol and / or at least one chelating agent selected from Na3PO4, CaSO4, Na2HPO4, Na3C6H5O7, and Na4P2O7 are added in step B to prepare the pre-foamed mixture. The function of each additive has been described in detail in the foregoing sections of this invention.

[0058] Optionally, in step C, the structural polymer-solvent mixture from step A and / or the pre-foamed mixture from step B are heated to a temperature in the range of 30-70°C, for example, 30-50°C, 50-70°C, or 40-60°C, preferably 35-65°C. In some aspects, the solvent in step A is preheated to a temperature in the range of 30-70°C, for example, 30-50°C, 50-70°C, preferably 35-65°C. In some aspects, the heating of at least one of the pre-foamed mixture and / or the structural polymer-solvent mixture is performed by preheating it to 35-75°C before introducing the solvent in step A. In some aspects, the temperature range is 30-100°C, for example, 35-65°C, or 65-100°C. In some aspects, when at least one structural polymer contains alginate, the temperature range is 30-70°C to sufficiently dissolve the alginate. In some aspects, when at least one structural polymer comprises alginate and gelatin, the temperature range is 30-100°C, for example, 65-100°C. In some aspects, the structural polymer of step A is added to a preheated solvent and mixed. The optional heating step of the structural polymer-solvent mixture of step A and / or the pre-foamed mixture of step B is to better dissolve at least one structural polymer in the solvent. Once the mixture reaches the desired temperature within this range, it is immediately removed from the heat source.

[0059] Third, the foaming mixture in step D is obtained by adding, to the pre-foaming mixture in step B, at least one foaming agent and / or at least one foam stabilizer and / or mechanical stirring to induce mechanical and / or chemical foaming. The functions of foaming agents and foam stabilizers have been described in detail in the foregoing sections of this invention.

[0060] In some aspects, at least one foam stabilizer is added to the pre-foamed mixture to prepare the foamed mixture. In a preferred aspect, the at least one foam stabilizer is a surfactant, preferably a green surfactant. As described in the detailed description above, the foam stabilizer can be used in conjunction with vigorous stirring to incorporate air during the mechanical foaming process. In some aspects, at least one blowing agent and / or at least one foam stabilizer is added to the pre-foamed mixture to prepare the foamed mixture. In a preferred aspect, at least one foam stabilizer is a surfactant, preferably a green surfactant, i.e., a biodegradable and / or recyclable surfactant, and at least one blowing agent is an enzymatic blowing agent, preferably a substrate of catalase, such as H2O2. By using at least one blowing agent alone or in combination with at least one foam stabilizer, chemical foaming and / or mechanical foaming can introduce more air than mechanical foaming alone. Only mechanical foaming is achieved at this stage because a second enzymatic blowing agent is required to initiate chemical foaming (see step E2). In some aspects, the pre-foamed mixture of step B is mixed with at least one foam stabilizer, preferably a surfactant selected from saponins, alkyl polysaccharides, sucrose esters, and sorbitol esters, and then the mixture is vigorously mixed to incorporate air during mechanical foaming. In some aspects, foaming is induced solely by mechanical means (such as whipping, stirring, or whisking), i.e., without the addition of a foam stabilizer. In some aspects, the pre-foamed mixture of step B is mixed with at least one blowing agent comprising a chemical or enzymatic blowing agent. In some aspects, the pre-foamed mixture of step B is mixed with at least one chemical or enzymatic blowing agent and at least one foam stabilizer comprising a surfactant. In some aspects, when the method is used to manufacture open-cell biofoam, at least one blowing agent is an enzymatic blowing agent.

[0061] Fourth, the gel mixture of step E is prepared by adding at least one gel initiator to the foaming mixture of step D. In some aspects, the at least one gel initiator is added to the foaming mixture under stirring, wherein the at least one gel initiator promotes the release of ions suitable for interacting with at least one structural polymer to form a stable foam structure. In some aspects, the at least one curing agent comprises a cation, such as calcium ions (Ca). 2+ ), magnesium ions (Mg 2+ ), potassium ions (K) + ) or aluminum ions (Al 3+ In some aspects, when at least one structural polymer comprises alginate, sodium alginate, potassium alginate, calcium alginate, or alginic acid, at least one gel initiator comprises a divalent cation, preferably Ca2+. 2+It exists in ionic form. In some aspects, when the structural polymer is sodium alginate, at least one curing agent is selected from calcium sulfate (CaSO4), calcium carbonate (CaCO3), and calcium chloride (CaCl2). The gelation process can be initiated by adding at least one gel initiator. In some aspects, the at least one gel initiator is in the form of providing a suitable temperature for gel initiation. The temperature required for gelation depends largely on at least one structural polymer used in the upstream steps of the method.

[0062] In some respects, this method is for producing open-cell, biodegradable biofoam. After the gelation process begins, at least one foaming agent may be selectively added to the gel mixture of step E to initiate an enzymatic foaming process in step E2. Here, the selected at least one foaming agent is determined based on the at least one foaming agent added in step D, i.e., during the preparation of the foaming mixture. In some respects, the at least one foaming agent added in step D is an enzymatic foaming agent, such as H2O2. Therefore, the at least one enzymatic foaming agent added in step E2 is a source of catalase, such as a yeast mixture. Adding the yeast mixture and stirring in step E2 will initiate the enzymatic foaming process. In some respects, the enzymatic foaming agent added in step E2 is selected from catalase, glucose oxidase, and α-amylase, preferably catalase.

[0063] Fifth, the gel mixture from step E or step E2 is transferred to the mold from step F, where the gelation process continues until completion. The time span from the gelation process to the solidification of the biofoam is approximately 30-90 minutes, for example, about 30-50 minutes, about 50-90 minutes, preferably 60 minutes. Sixth, after the gelation process is complete, the gel from step F is demolded and dehumidified or dried in step G. In some cases, the bio-foam is dried in a dehumidifier combined with hot air drying at a temperature range of 30-40°C (e.g., 30-35°C or 35-40°C, preferably 36°C), thereby creating a vacuum effect. The drying time depends on parameters such as the drying temperature and the amount of gel product. The drying time can last from 1 to 7 days, for example 1 to 4 days, for example 3 to 7 days, preferably 3 days.

[0064] While a preferred order of method steps has been mentioned above, the method is not strictly limited to this particular order. The invention may also be limited to the order of the method steps described above. In some aspects, in the method described above, the drying of the foam includes a drying stage, while in other methods it includes a wet stage.

[0065] Table 1 shows examples of specific concentrations (wt%) of the components used in the methods described herein for producing the closed-cell foam (column 2) and open-cell foam (column 3) described herein. In this document, the biofoam comprises sodium alginate as a structural polymer, CaCO3 and cellulose nanofibers as biodegradable and / or recyclable fillers, Na3PO4 as a chelating agent, and CaSO4 as a gel initiator. Specific quantities are for reference only and may vary. The biofoam may include a structural polymer, namely alginate, in a content of 50-95% by weight, for example 50-65% by weight, for example 65-95% by weight, more preferably 60-90% by weight. The biofoam may contain CaCO3 as a filler in a content of 0.2-31% by weight, for example 0.2-3% by weight, for example 3-10% by weight, or 10-31% by weight, preferably 0.3-10% by weight. The biofoam also contains cellulose nanofibers as filler, with a content of 1-80% by weight, for example 1-25% by weight, for example 25-50% by weight, for example 50-80% by weight, preferably 5-45% by weight.

[0066]

[0067] Table 1: Exemplary specific concentrations (wt%) of components used in methods for preparing representative closed-cell and open-cell foams using sodium alginate (Na-alginate) as the structural biopolymer and CaCO3 and cellulose nanofibers as two recyclable and / or biodegradable fillers. In the exemplary specific concentrations disclosed herein, the weight percentage of sodium alginate is calculated based on the dry weight of sodium alginate. If converted to water-soluble sodium alginate, i.e., a sodium alginate solution, the weight percentage of the sodium alginate solution corresponds to approximately 77% by weight.

[0068] Depending on whether the method is used to produce foam materials for testing and characterizing foam properties, or for large-scale foam production, there are several alternative variations of the method for manufacturing biodegradable biofoam. Example 1 describes an alternative variation of the method for producing a closed-cell variant of biodegradable biofoam for testing and / or characterizing foam materials. Example 2 describes an alternative variation of the method for producing an open-cell variant of biodegradable biofoam for testing and / or characterizing foam materials. Other variations of the method, such as methods for large-scale production, may include steps or conditions from the methods described in Examples 1 and / or 2, combined with additional steps and / or conditions depending on the desired composition and properties of the biodegradable biofoam material.

[0069] The materials disclosed in this invention can be used in a wide range of applications. Non-limiting examples of such applications include furniture upholstery, shoe insoles, sound insulation materials, seat upholstery, headphone pads, microphone pads, and other applications that typically use flexible polyurethane. Therefore, in some aspects, this invention relates to objects comprising a biodegradable biofoam selected from furniture upholstery, shoe insoles, seat upholstery, headphone pads, microphone pads, sound insulation materials, and automotive seat upholstery. This biodegradable biofoam contains at least 80% bio-based material and, as tested by the applicant in Example 3, has been found to have surprising flame-retardant properties. Therefore, this biofoam is suitable for applications with stringent fire safety requirements, such as automotive seats. This biofoam offers a highly attractive alternative to traditional flame retardants, which often contain substances harmful to health. These flame retardants contain substances that can easily leak into the surrounding environment over time, reducing their flame-retardant effect, compromising safety, and posing potential health risks upon exposure.

[0070] As shown in this disclosure, the inherent properties of each component or reagent and how they interact to affect the final properties and performance of the foam can be carefully considered. Those skilled in the art will understand that various components, such as the type of structural polymer, filler, chelating agent, blowing agent, and foam stabilizer, can be selected based on the desired properties and characteristics of the biopolymer-based foam. While specific aspects and examples are provided herein for illustration, they are not intended to be limiting. This disclosure provides guidance, principles, and general methods to enable those skilled in the art to select appropriate components based on the intended application and specific requirements of the biopolymer-based foam.

[0071] Example Example 1: A method for producing a closed-cell variant of biodegradable alginate biofoam for testing and / or characterization purposes.

[0072] One aspect of the invention includes a method for producing closed-cell variants of biofoam (as disclosed in the second column of Table 1 or Table 2), the method comprising the following steps / method steps: 1. Heat water to 35-65°C on a magnetic stirrer. Remove from heat. Add sodium alginate and stir until smooth. Cover and let stand overnight in a refrigerator at 2°C.

[0073] a. The next day, stir again before adding other ingredients to ensure the mixture is smooth.

[0074] 2. Add glycerol, calcium carbonate (CaCO3), and sodium phosphate (Na3PO4) to the water-alginate mixture. Heat to 35-65℃ (different temperatures will result in different properties of the final product).

[0075] a. If necessary: ​​Add additional structural components or fillers.

[0076] 3. Remove from the heat source.

[0077] 4. Add cellulose and stir until smooth at the maximum ratio. 5. Add the surfactant and stir at the maximum ratio until fully incorporated and the mixture is foamy.

[0078] 6. Add calcium sulfate (CaSO4) and stir thoroughly. This will initiate the gelation process.

[0079] 7. Transfer to a mold and let it gel in the mold for 1 hour.

[0080] 8. After gelation, pour the gel foam out of the mold and dry it in a ventilated drying cabinet at 50-60℃.

[0081] 9. Place the bio-foam gel in a ventilated drying cabinet. The bio-foam is dried using a combination of dehumidification and hot air drying (HAD) to create a vacuum effect. The drying process is carried out at 36°C for 3 days.

[0082] The ratio of bio-based materials and / or renewable materials to inorganic compounds in the prepared bio-foam is approximately 30:1.

[0083] Example 2: Method for manufacturing an open-cell variant of biodegradable alginate biofoam for testing and / or characterization purposes.

[0084] One aspect of the invention includes a method for manufacturing open-cell variants of biofoam (as disclosed in the third column of Table 1 or Table 2), the method comprising the following steps / method steps: 1. Heat water to 35-65°C on a magnetic stirrer. Remove from heat. Add sodium alginate and stir until smooth. Cover and let stand overnight in a refrigerator at 2°C.

[0085] a. The next day, stir again before adding other ingredients to ensure the mixture is smooth.

[0086] 2. Add glycerol, calcium carbonate (CaCO3), and sodium phosphate (Na3PO4) to the water-alginate mixture. Heat to 35-65℃ (different temperatures will result in different properties of the final product). a. If necessary: ​​Add additional structural components or fillers.

[0087] 3. Remove from the heat source.

[0088] 4. Add cellulose and stir until smooth at the maximum ratio. 5. Add the surfactant and H2O2. Stir at maximum ratio until fully combined and the mixture is slightly foamy.

[0089] 6. Add calcium sulfate (CaSO4) and stir thoroughly. This will initiate the gelation process.

[0090] 7. Add the yeast mixture and stir quickly but thoroughly. The mixture will increase in volume due to the enzymatic foaming process, in which yeast catalase converts H2O2 into O2 and H2O. This will release air into the mixture, creating bubbles.

[0091] 8. Transfer to a mold and allow it to gel.

[0092] 9. After gelling, remove from the mold and place on a metal mesh drying tray. Place the metal mesh tray on top of the foam as well. This prevents shrinkage during drying.

[0093] 10. Dry in a ventilated drying oven at 50-60℃.

[0094] 11. Place the bio-foam gel in a ventilated drying cabinet. The bio-foam is dried using a combination of dehumidification and hot air drying (HAD) to create a vacuum effect. The drying process is carried out at 36°C for 3 days.

[0095] Table 2 lists the concentrations of specific materials (components) used in the preparation of closed-cell variants (column 2) and open-cell variants (column 3) of biodegradable sodium alginate biofoam for testing and / or characterization purposes.

[0096] Table 2: Exemplary specific concentrations (by weight or volume) of closed-cell variants (column 2) and open-cell variants (column 3) for the preparation of biodegradable sodium alginate biofoam for testing and / or characterization purposes.

[0097] Example 3: The flame retardant properties of a bio-foam according to one aspect were evaluated by Crib 5 test.

[0098] The tested biofoam is a biofoam according to the preferred aspects described above, comprising at least one structural component, which is 60-90% by weight alginate, and at least one biodegradable and / or recyclable filler comprising 0.3-10% by weight CaCO3 and 5-45% by weight cellulose nanofibers.

[0099] The flame-retardant properties of bio-foam were tested using the Crib 5 fire resistance test (also known as the ignition source 5 test). This test is designed to evaluate the fire resistance of materials used in upholstered furniture, such as fabrics, foams, and fillings. It assesses the behavior of the material when exposed to flame, simulating a potential ignition source.

[0100] The bio-foam sample dimensions (width x depth x height) are 41 cm x 25 cm x 2.5 cm. Two pieces of the same type of bio-foam are stacked together and placed on top of a woodpile or log, simulating the situation of bio-foam used for purposes such as interior decoration, furniture upholstery, or car seat upholstery near a potential ignition source. The woodpile is ignited, and the flame is allowed to burn for a specified time, or until the fire extinguishes itself without intervention. For the sample to pass the test, the fire must self-extinguish within 10 minutes. Furthermore, the fire should not completely burn through the thickness of the test material.

[0101] The biofoam sample self-extinguished after 4 minutes and 17 seconds. A weight loss of 28.6 grams was recorded, leaving approximately 2471.4 grams of unburned material after the flame extinguished. Furthermore, the charred area measured on the biofoam surface was only 9 centimeters in diameter. The fire failed to burn through the uppermost of the two stacked biofoam samples.

[0102] Therefore, the bio-foam according to the preferred aspects successfully passed the Crib 5 test, indicating that the bio-foam meets the fire resistance rating defined by the Crib 5 test. This demonstrates that the bio-foam described herein has potential applications, which can reduce the risk of fire-related accidents and improve overall safety.

Claims

1. Biodegradable bio-foam, comprising: At least 80% by weight of bio-based materials and / or renewable materials, including: At least one structural component, wherein the at least one structural component is a hydrocolloid; Up to 20% by weight of bio-derived inorganic compounds; as well as One or more additives, including at least two biodegradable and / or recyclable fillers, said fillers including CaCO3 and cellulose nanofibers.

2. The biodegradable biofoam according to claim 1, wherein the at least one structural component comprises alginate.

3. The biodegradable biofoam according to any one of the preceding claims, wherein the at least one structural component comprises alginate and gelatin, or alginate and chitin, or alginate and cellulose, or alginate and cellulose nanofibers, or alginate and chitosan.

4. The biodegradable biofoam according to any of the preceding claims, wherein the alginate component comprises sodium alginate, potassium alginate, or calcium alginate.

5. The biodegradable biofoam according to any one of the preceding claims, further comprising at least one gel initiator.

6. The biodegradable biofoam according to claim 1 or claim 5, wherein claim 5 refers to claim 1, and wherein the at least one structural component is a hydrocolloid selected from agar, carrageenan, cellulose, cellulose nanofibers, chitosan, chitin, pectin, guar gum, xanthan gum, wet seaweed, dry seaweed and gelatin.

7. The biodegradable biofoam according to any one of the preceding claims, wherein the biodegradable and / or recyclable filler comprises: CaCO3, with a content ranging from 0.2-35% by weight, preferably 0.3-10% by weight; and Cellulose nanofibers, with a content ranging from 1-80% by weight, preferably 5-45% by weight.

8. The biodegradable biofoam according to any of the preceding claims, wherein the at least one structural component comprises alginate in an amount of 50-95% by weight, preferably 60-90% by weight.

9. The biodegradable biofoam according to any of the preceding claims, comprising at least one biodegradable and / or recyclable filler selected from chitin and chitosan.

10. The biodegradable biofoam according to any of the preceding claims, wherein the biodegradable biofoam is a molded foam.

11. The biodegradable biofoam according to any of the preceding claims, wherein the biodegradable biofoam is a closed-cell foam.

12. The biodegradable biofoam according to any of the preceding claims, wherein the biodegradable biofoam is an open-cell foam.

13. A method for producing biodegradable biofoam, comprising: A structural polymer-solvent mixture is prepared by mixing at least one structural component, including a hydrocolloid, and a solvent; A pre-foamed mixture is prepared by mixing the structural polymer-solvent mixture with one or more additives, the additives comprising at least two biodegradable and / or recyclable fillers, the biodegradable and / or recyclable fillers comprising CaCO3 and cellulose nanofibers; At least one of the pre-foamed mixture and the structural polymer-solvent mixture is heated to a temperature range of 30-70°C; A foamed mixture is prepared by introducing at least one of induced mechanical foaming and chemical foaming into the pre-foamed mixture, for example by adding a foaming agent, a foam stabilizer, and applying mechanical stirring; A gel mixture is prepared by providing at least one gel initiator to the foaming mixture; The foam is shaped in a mold; Dry the foam; wherein, Drying the foam includes a drying stage, while the remaining steps include a wet stage.

14. The method of claim 13, further comprising adding at least one additional structural component to the pre-foamed mixture.

15. The method according to any one of claims 13 or 14, wherein at least one structural component used to prepare the structural polymer-solvent mixture is an alginate.

16. The method according to any one of claims 13-15, in, The solvent is water; Furthermore, the heating of at least one of the pre-foamed mixture and the structural polymer-solvent mixture is performed by preheating the solvent to 35°C-75°C before introducing the solvent. Wherein, at least one structural component of the structural polymer-solvent mixture is selected from alginate, sodium alginate, potassium alginate, calcium alginate, and alginic acid.

17. The method according to any one of claims 13-16, The preparation of the pre-foamed mixture also includes at least one of the following: Add at least one additional structural component, wherein each additional structural component is selected from agar, carrageenan, cellulose, cellulose nanofibers, pectin, guar gum, xanthan gum, gelatin, chitin, chitosan, and fucoidan; and Add at least one additional biodegradable and / or recyclable filler selected from chitosan and chitin.

18. A method for producing a biodegradable biofoam with open cells according to any one of claims 13-17, comprising: Hydrogen peroxide is added together with the stabilizer; as well as Add the yeast mixture to the prepared gel mixture before transferring it to the mold.

19. A method for producing biodegradable biofoam according to any one of claims 13-18.

20. An object comprising a biodegradable biofoam according to claims 1-12 or 19, wherein the object is selected from furniture padding, shoe insoles, seat padding, headphone padding, microphone padding, sound insulation materials, and automotive seat padding.

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