Methods for forming structured cellulosic material

Abstract

In various aspects, a method for forming structured cellulosic material is provided. The method may include providing a fibrous material containing lignin. The method may include performing partial cold caustic extraction in combination with use of a rolling mill on the fibrous material containing lignin to generate a plurality of fibers. The method may include neutralizing and drying the plurality of fibers. The method may include forming a slurry by mixing a desiccant, a binder, and the plurality of fibers. The method may include introducing the slurry into a mould while under pressure. The method may include allowing the slurry to at least partially cure in the mould.

Description

[0001] METHODS FOR FORMING STRUCTURED CELLULOSIC MATERIAL

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present application claims priority to U.S. Provisional Patent Application 63 / 675,607, filed July 25, 2024, the contents of which are incorporated by reference herein in its entirety.

[0004] TECHNICAL FIELD

[0005] The present disclosure is drawn to techniques for forming structured cellulosic materials, and in particular, techniques for partially delignifying and re-lignifying wood-based materials.

[0006] BACKGROUND

[0007] This section is intended to introduce the reader to various aspects of the art, which may be related to various aspects of the present disclosure that are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0008] Current wood-based material manufacturing exists along a spectrum of processing intensity and waste generation. At one end, highly processed materials like wood pulp products (paper, cardboard, MDF) utilize extensive chemical and mechanical processing that breaks down the wood’s intrinsic cellulose and lignin structure, resulting in structurally weak products with minimal waste generation. At the other end of the spectrum, materials like glue-laminated timber, plywood, and chipboard require minimal chemical processing but rely on higher- quality wood feedstock, producing stronger products but generating significant waste from selective material usage. Thus, there is a significant need for processes that can produce high structural performance while minimizing both chemical processing and waste generation.

[0009] BRIEF SUMMARY

[0010] Various deficiencies in the prior art are addressed below by the disclosed methods for forming structured cellulosic material.

[0011] In various aspects, a method for forming structured cellulosic material may be provided. The method may include providing a fibrous material containing lignin. The method may also include performing partial cold caustic extraction in combination with use of a rolling mill on the fibrous material containing lignin to generate a plurality of fibers having a range of lengths and having a desired thickness or diameter. The range of lengths may include longer length fibers, shorter length fibers, and intermediate length fibers.

[0012] The method may also include neutralizing and drying the plurality of fibers. The method may also include forming a slurry by mixing a desiccant, a binder, and the plurality of fibers. The method may also include introducing the slurry into a mould while under pressure. The method may also include allowing the slurry to at least partially cure in the mould. The incorporation of the shorter length fibers and intermediate length fibers may create a final structured material that has a reduced void space between fibers than a structured material utilizing only the longer length fibers.

[0013] In some embodiments, utilizing the rolling mill may include rolling only a portion of the fibrous material containing lignin.

[0014] In some embodiments, performing the partial cold caustic extraction in combination with use of a rolling mill may include soaking a fibrous material containing lignin in a sodium hydroxide (NaOH) solution at a temperature no more than 35°C for cold caustic extraction. Performing the partial cold caustic extraction in combination with use of a rolling mill may also include utilizing a rolling mill to form a plurality of fibers and to partially reduce the thickness of the fibrous material containing lignin. Performing the partial cold caustic extraction in combination with use of a rolling mill may include repeating the soaking of the fibrous material containing lignin in the sodium hydroxide solution and utilizing the rolling mill a predetermined number of repetitions. The predetermined number of repetitions may be at least 10. The predetermined number of repetitions may be between 1-9. In some embodiments, the rolling mill may be utilized multiple times following each soaking of the fibrous material containing lignin.

[0015] In some embodiments, the sodium hydroxide solution may include sodium hydroxide at a concentration of at least 2.5% by weight of sodium hydroxide solution. The sodium hydroxide may be present at a concentration of 18% to 22% by weight of sodium hydroxide solution.

[0016] In some embodiments, neutralizing and drying the plurality of fibers may include neutralizing the plurality of fibers to a target pH using one or more acids. Neutralizing and drying the plurality of fibers may include removing at least some liquid absorbed by the plurality of fibers, by using a device to squeeze the plurality of fibers and / or allowing the plurality of fibers to air dry. The device may be a rolling mill. Neutralizing and drying the plurality of fibers may further include immersing the fibers in a mixture including a silica source and allowing the fibers to interact with the silica source. The silica source may be at least one of tetraethyl orthosilicate (TEOS) and a colloidal silicate. In some embodiments, the method may further include drying the plurality of fibers after at least some of the silica source has been absorbed.

[0017] In some embodiments, the method may further include sorting the plurality of fibers by length. In some embodiments, sorting the plurality of fibers by length may include sorting the plurality of fibers into three or more groups of fibers based group having a different range of fiber lengths. In some embodiments, the method may further include preparing a blend of fibers. The blend of fibers may have a predetermined ratio of fibers of different lengths.

[0018] In some embodiments, the desiccant may be a sulfate. The sulfate may be magnesium sulfate (MgSCfi) and / or calcium sulfate ('CaS(Ti).

[0019] In some embodiments, the desiccant may be at least one of bentonite, clay, calcium chloride (CaCh), calcium oxide (CaO), lithium bromide (LiBr), sodium chloride (NaCl), plaster, magnesium oxide (MgO), sodium hydroxide (NaOH), and sulfuric acid (H2SO4).

[0020] In some embodiments, forming the slurry may include forming a dry mixture including the desiccant and a lignin. Forming the slurry may include forming an aqueous mixture including aqueous lignin, a laccase enzyme, optionally a silica source, optionally a colloidal silicate, and optionally a C2-C4 monoalcohol. Forming the slurry may include forming wet fibers by immersing the plurality of fibers into the aqueous mixture for a predetermined period of time. Forming the slurry may include forming the slurry by combining the wet fibers with the dry mixture, and mixing. The silica source may be tetraethyl orthosilicate (TEOS) and / or colloidal silicate. The C2-C4 monoalcohol may be ethanol. The aqueous lignin may include at least some of the sodium hydroxide solution used in the partial cold caustic extraction.

[0021] In various aspects, a structural composition may be provided. The structural composition may include a plurality of relatively long, lignin-containing fibers, that are oriented in three dimensions. The structural composition may also include a plurality of medium and relatively short, lignin-containing fibers. The plurality of medium and relatively short, lignin containing fibers may be disposed in volumes of space between the relatively long, lignin containing fibers.

[0022] The plurality of relatively long, lignin-containing fibers may be substantially uniformly oriented in three dimensions. The plurality of relatively long, lignin-containing fibers may be substantially randomly oriented in three dimensions. Additional objects, advantages, and features of the present disclosure will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the present disclosure. The objects and advantages of the present disclosure may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

[0023] BRIEF DESCRIPTION OF FIGURES

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with a general description of the present disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

[0025] Figure 1 shows a flow diagram of an embodiment of a method.

[0026] Figure 2 A shows an embodiment of a mould system for curing the plurality of fibers.

[0027] Figure 2B shows an exploded view of a mould system for curing the plurality of fibers.

[0028] Figure 3 A shows an embodiment of a structural composition.

[0029] Figure 3B shows a cross-sectional view of an embodiment of a structural composition.

[0030] Figure 4 shows an embodiment of a molded structural composition.

[0031] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the present disclosure. The specific design features or the sequence of operations as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes of various illustrated components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration.

[0032] DETAILED DESCRIPTION

[0033] The following description and drawings merely illustrate the principles of the present disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the present disclosure and are included within its scope. Furthermore, all examples recited herein are principally intended expressly to be only for illustrative purposes to aid the reader in understanding the principles of the present disclosure and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Additionally, the term, "or," as used herein, refers to a nonexclusive or, unless otherwise indicated (e.g., “or else” or “or in the alternative”). Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0034] The numerous innovative teachings of the present application will be described with particular reference to the presently preferred exemplary embodiments. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the claims. Moreover, some statements may apply to some features but not to others. Those skilled in the art and informed by the teachings herein will realize that the present disclosure is also applicable to various other technical areas or embodiments.

[0035] Disclosed are various fabrication techniques that may result in one or more types of compositions of matter. At a high level, these fabrication techniques involve partially delignifying wood and then re-lignifying it with selected additives (e.g., laccase, de-alkali lignin, or desiccants). The process may also include the use of a rolling mill to obtain fibers of varying lengths. Using a rolling mill maximally preserves the original strength of the wood’s cellulose fiber bundles and allows for efficient processing on a commercial scale, regardless of tree species or initial wood dimensions.

[0036] Incorporating fibers of different lengths reduces or eliminates the need for heavy pressing and artificial binders such as formaldehyde, thereby broadening the potential applications of the resulting material beyond conventional sheet goods and milled products. However, when pressing is applied, the material can achieve even greater strength. Additionally, by deconstructing and reconstructing the wood structure, various additives - such as sharp sand - can be incorporated to further enhance specific mechanical properties or provide other desirable characteristics.

[0037] A structural composition produced using the disclosed method may include a mixture of long, medium, and short fibers, with the specific ratios tailored to the intended application. The long fibers provide the primary structural strength and load-bearing capacity of the composition. The spaces between these long fibers are filled with medium-length fibers, and this infilling process may be repeated recursively down to the sub-millimeter scale. These shorter gap-filler fibers may act as interlinkers between the longer fibers, maximizing cross- linking, enhancing multi-axis rigidity, and significantly reducing the need for artificial binders such as formaldehyde.

[0038] As used herein, the term “wood” is used to refer broadly to any plant-based material that contains cellulose and hemicellulose fibers interlinked with lignin. This definition is not limited to traditional tree-derived wood but may also encompass a wide range of lignocellulosic feedstocks, including but not limited to trees, grasses, agricultural residues, hemp, bamboo, and other fibrous plant materials containing lignin. Utilizing a diverse range of renewable, lignin-containing biomass allows for greater flexibility in feedstock selection and promotes the use of underutilized or non-traditional plant materials.

[0039] The strength of the resulting composition derives from the friction between the fibers and the lignin polymers that interlink them. Unlike conventional pulping, this process only partially delignifies the wood using a mild caustic solution. This partial delignification, combined with processing through a rolling mill, acts as a natural selection step: the caustic solution penetrates and weakens the less dense fiber regions, while the tightly packed, stronger fiber bundles remain intact. When tangential pressure is applied, the fibers separate along these weakened, delignified areas. To cure the product, materials such as laccase and additional dealkali lignin are added. The laccase enzyme promotes polymerization between the cleaved lignin and the added lignin, effectively interlinking the fiber bundles. This partial delignification is advantageous because the remaining lignin is already covalently bonded to hemicellulose, eliminating the need for additional chemical bonding of the new lignin macromolecules to the fiber bundles.

[0040] Because fiber-to-fiber friction is a major contributor to overall strength, fiber alignment also plays a significant role in determining the material’s mechanical properties. Since the fibers are produced using a rolling mill, they are much longer in one dimension, resulting in needle-like or oval cross-sectional shapes. This enables the creation of various anisotropic configurations during the curing stage, producing a natural material with a wide range of strength characteristics. Additionally, the combination of long fiber bundles and lignin - which has low water solubility at room temperature - reduces swelling compared to products like medium-density fiberboard, minimizing the loss of strength due to moisture absorption.

[0041] Referring to FIG. 1, a flow diagram of a method for forming structured cellulosic material (100) is shown. The method may include providing (110) a fibrous material containing lignin. Non-limiting examples of fibrous material containing lignin may include, for example, natural woods (e.g., oak, pine, spruce, etc.), wood waste and byproducts, woody plants and shrubs (e.g., willow, poplar eucalyptus, hemp stalks), and bark. The method may also include performing (120) partial cold caustic extraction. Cold caustic extraction may include treating (e.g., soaking) the fibrous material containing lignin with a cold alkaline solution. The caustic solution breaks down lignin bonds and dissolves hemicelluloses while leaving cellulose fibers relatively intact. In some embodiments, the cold alkaline solution may be a sodium hydroxide solution and / or potassium hydroxide.

[0042] Performing the cold caustic extraction may be in combination with use of a rolling mill on the fibrous material containing lignin to generate a plurality of fibers having a range of lengths and having a desired thickness or diameter. The range of lengths may include longer length fibers, shorter length fibers, and intermediate length fibers. The longer length fibers may be longer than the intermediate length fibers and shorter length fibers. The intermediate length fibers may be longer than the shorter length fibers. The shorter length fibers may be shorter than the longer length fibers and the intermediate length fibers.

[0043] The longer length fibers may have an axial length greater than the intermediate length fibers and the shorter length fibers. In some embodiments, the longer length fibers may have an axial length between about 20 mm to 2000 mm. The longer length fibers may have an axial length between about 20 mm to 1500 mm. The longer length fibers may have an axial length between about 50 mm to 1250 mm. The longer length fibers may have an axial length between about 100 mm to 1000 mm. The longer length fibers may have an axial length between about 200 mm to 800 mm. The longer length fibers may have an axial length between about 400 mm to 600 mm.

[0044] The intermediate length fibers may have an axial length greater than the shorter length fibers and shorter than the longer length fibers. The intermediate length fibers may have an axial length between about 11 mm to 19 mm. The intermediate length fibers may have an axial length between about 12 mm to 18 mm. The intermediate length fibers may have an axial length between about 13 mm to 17 mm. The intermediate length fibers may have an axial length between about 14 mm to 16 mm.

[0045] The shorter length fibers may have an axial length shorter than the intermediate length fibers and the longer length fibers. The shorter length fibers may have an axial length between about 0.1 mm to 1 mm. The shorter length fibers may have an axial length between about 0.2 mm to 0.8 mm. The shorter length fibers may have an axial length between about 0.3 mm to 0.7 mm. The shorter length fibers may have an axial length between about 0.4 mm to 0.6 mm.

[0046] In some embodiments, the rolling mill may include one or more “teeth”. The one or more teeth may be utilized to split the fibrous material containing lignin into strands. The method may also include neutralizing and drying (130) the plurality of fibers. The plurality of fibers may be dried using various techniques. For example, the plurality of fibers may be air dried by spreading them into thin layers on screens or perforated surfaces and allowing natural air circulation to evaporate moisture at ambient temperatures. In another example, the plurality of fibers may be dried using heated air circulation to accelerate moisture removal, which can be performed in convection ovens or specialized drying chambers. In yet another example, the plurality of fibers may be dried via vacuum drying, where reduced pressure lowers the boiling point of water to enable drying at lower temperatures. Additionally, the plurality of fibers may be dried using mechanical dewatering techniques, such as applying centrifugal forces or pressing to remove excess water from the plurality of fibers. The various drying techniques described above may be applied independently or in combination with one another. Those skilled in the art and informed by the teachings herein will appreciate that other suitable drying techniques may also be applied to the plurality of fibers.

[0047] The method may also include forming (140) a sluny by mixing a desiccant, a binder, and the plurality of fibers.

[0048] The method may also include introducing (150) the slurry into a mould while under pressure. The pressure may be applied tangentially using a mechanical press, or by vacuum- assisted molding techniques wherein negative pressure draws the slurry into the mould cavity. In some embodiments, pressure may be applied hydraulically, pneumatically, or through centrifugal force generated by rotating the mould assembly.

[0049] The method may also include allowing (160) the slurry to at least partially cure in the mould. The incorporation of the shorter length fibers and intermediate length fibers may create a final structured material that has a reduced void space between fibers than a structured material utilizing only the longer length fibers. In some embodiments, the slurry may cure in the mould for about 6-72 hours. In some embodiments, the slurry may cure in the mould for about 12-60 hours. The slurry may cure in the mould for about 18-54 hours. The slurry may cure in the mould for about 24-48 hours. The sluny may cure in the mould for about 30-42 hours.

[0050] In some embodiments, utilizing the rolling mill may include rolling only a portion of the fibrous material containing lignin. For example, for large diameter source materials, the rolling mill may not be able to process the entire material in a singular pass. Additionally, because each pass through the rolling mill typically reduces the material’s thickness by only a small fraction of its maximum dimension, multiple passes or partial processing may be necessary to achieve the desired reduction and fiber separation throughout the entire material. In some embodiments, performing the partial cold caustic extraction in combination with use of a rolling mill may include soaking a fibrous material containing lignin in a sodium hydroxide solution at a temperature no more than 35°C for cold caustic extraction. Performing the cold caustic extraction may include utilizing a rolling mill to form a plurality of fibers and to partially reduce the thickness of the fibrous material containing lignin.

[0051] In some embodiments, partial cold caustic extraction may be performed in combination with a rolling mill. This process may involve repeating the soaking of the fibrous material containing lignin in a sodium hydroxide (NaOH) solution, followed by utilizing the rolling mill a predetermined number of repetitions. The number of repetitions is predetermined based on factors such as the desired fiber dimensions, flexibility, and the inherent characteristics of the source material (e.g., hardwood, softwood, bamboo).

[0052] The term "repetition" in this context may be defined in various ways, depending on processing goals or material constraints. For instance, a single repetition may consist of one soaking stage followed by a single pass through the rolling mill. Alternatively, it may be defined as one soaking stage followed by multiple consecutive passes through the rolling mill. This flexibility in defining a repetition allows the process to be tailored to different materials and desired mechanical properties, enabling finer control over fiber morphology and surface chemistry.

[0053] In some embodiments, the predetermined number of repetitions may be at least 10. In some embodiments, the predetermined number of repetitions may be between about 1-50. The predetermined number of repetitions may be between about 1 -40. The predetermined number of repetitions may be between about 1-30. The predetermined number of repetitions may be between about 1-20. The predetermined number of repetitions may be between about 1-9. The predetermined number of repetitions may be between about 1-6. The predetermined number of repetitions may be between about 1-4. The predetermined number of repetitions may be between about 1-2.

[0054] In some embodiments, the rolling mill may be utilized multiple times following each soaking of the fibrous material containing lignin. For example, the rolling mill may be utilized at least twice following each soaking of the fibrous material containing lignin. The rolling mill may be utilized at least three times following each soaking of the fibrous material containing lignin. The rolling mill may be utilized at least five times following each soaking of the fibrous material containing lignin. The rolling mill may be utilized at least ten times following each soaking of the fibrous material containing lignin. In some embodiments, the sodium hydroxide solution may include sodium hydroxide at a concentration of at least 1.5%. In some embodiments, the sodium hydroxide solution may include sodium hydroxide at a concentration of at least 2.5%. The sodium hydroxide solution may include sodium hydroxide at a concentration of at least 6%. The sodium hydroxide solution may include sodium hydroxide at a concentration of at least 9%. The sodium hydroxide solution may include sodium hydroxide at a concentration of at least 12%. The sodium hydroxide solution may include sodium hydroxide at a concentration of at least 15%. The sodium hydroxide solution may include sodium hydroxide at a concentration of at least 20%. The sodium hydroxide solution may include sodium hydroxide at a concentration of at least 30%.

[0055] In some embodiments, the sodium hydroxide may be present at a concentration of 5% to 40% by weight of sodium hydroxide solution. The sodium hydroxide may be present at a concentration of 10% to 30% by weight of sodium hydroxide solution. The sodium hydroxide solution may be present at a concentration of 12% to 28% by weight of sodium hydroxide solution. The sodium hydroxide solution may be present at a concentration of 14% to 26% by weight of sodium hydroxide solution. The sodium hydroxide solution may be present at a concentration of 16% to 24% by weight of sodium hydroxide solution. The sodium hydroxide solution may be present at a concentration of 18% to 22% by weight of sodium hydroxide solution. The sodium hydroxide solution may be present at a concentration of 19% to 21% by weight of sodium hydroxide solution. The sodium hydroxide solution may be present at a concentration of 19.5% to 20.5% by weight of sodium hydroxide solution.

[0056] In some embodiments, neutralizing and drying the plurality of fibers may include neutralizing the plurality of fibers to a target pH using one or more acids (e.g., HC1). Neutralizing and drying the plurality of fibers may include removing at least some liquid absorbed by the plurality of fibers. Removing at least some liquid absorbed by the plurality of fibers may be accomplished via a device to squeeze the plurality of fibers and / or allowing the plurality of fibers to air dry. In some embodiments, the device may be a rolling mill. Other suitable devices may include, but are not limited to, a rolling mill, a belt press, a twin-screw extruder, or a nip roller system.

[0057] In some embodiments, the method may further include immersing the fibers in a mixture. The mixture may include a silica source. The method may further include allowing the fibers to interact with the silica source. In some cases, the fibers may interact with the silica source by e.g., absorbing the silica source. In some embodiments, the silica source may be tetraethyl orthosilicate (TEOS) and a colloidal silicate. Those skilled in the art and informed by the present disclosure will appreciate that the silica source is not limited to TEOS. For example, in other embodiments, the silica source may include other alkoxysilanes such as tetramethyl orthosilicate (TMOS), methyltrimethoxysilane (MTMS), or ethyl silicate. Alternatively, the silica source may be a colloidal silica dispersion, a sodium silicate solution, or an organosilane precursor such as silane coupling agents.

[0058] In some embodiments, the target pH may be between about 4-5.5. In some embodiments, the target pH may be between about 4.2 to 5.3. The target pH may be between about 4.4 to 5. 1. The target pH may be between about 4.6-4.9. In some embodiments, the target pH may be between about 4.8-6.0. The target pH may be between about 5.0-5.8. The target pH may be between about 5.2-5.6. The target pH may be between about 5.3-5.5. A target pH may be about 4.5 for embodiments which utilize TEOS while a target pH may be about 5.5 for embodiments which do not utilize TEOS. The target pH may be selected to strike the balance of Lacasse reaction vs. TEOS polymerization.

[0059] In some embodiments, neutralizing and drying the plurality of fibers may further include drying the plurality of fibers after at least some of the silica source has been absorbed.

[0060] In some embodiments, the method may further include sorting the plurality of fibers by length. Sorting the plurality of fibers by length may include sorting the plurality of fibers into three or more groups of fibers based group having a different range of fiber lengths. Sorting may occur before, during, or after other processing steps, depending on the desired fiber characteristics and the intended application.

[0061] Various techniques may be used to perform the sorting, including mechanical sieving, air classification, fluidized bed separation, or optical and laser-based systems capable of detecting and segregating fibers by length. This classification enables precise control over downstream processing and material performance. Length-sorted fibers can improve product uniformity, enhance mechanical properties, and allow for targeted functionalization. The sorting process may be carried out manually, automatically, or through a hybrid approach, and may include rejecting or recycling fibers that fall outside the acceptable length thresholds.

[0062] In some embodiments, the plurality of fibers may be sorted into three or more groups of fibers based group. Each group may have a different range of fiber lengths. For example, the fibers may be categorized into short, intermediate, and long fiber groups, or divided into additional groups to achieve finer length gradation. The specific length ranges for each group may be selected based on the intended application, desired material properties, or processing requirements. Sorting into multiple length-based groups can facilitate tailored blending ratios, optimize the packing density, or improve the alignment and distribution of fibers in the final product.

[0063] In some embodiments, the method may further include preparing a blend of fibers. The blend of fibers may have a predetermined ratio of fibers of different lengths. The preparation of the blended fibers may be carried out by combining the sorted fiber groups in controlled quantities using batching equipment, weighing systems, or automated feed mechanisms to ensure precise ratios. The fibers may be mixed using mechanical mixers, blenders, or air agitation systems to achieve a uniform distribution of lengths throughout the blend. While a uniform distribution of lengths throughout the blend may be preferred in some use cases, those skilled in the art and informed by the present disclosure will appreciate that non-uniform distributions of lengths may be preferential in other use cases. In some embodiments, the blending process may also include the addition of binder, additives, or functionalizing agents to enhance the bonding or performance of the fibers in the composite material or matrix.

[0064] In some embodiments, the desiccant may be a sulfate. The sulfate may be magnesium sulfate (MgSOfi and / or calcium sulfate (CaSOty. In other embodiments, the sulfate may include sodium sulfate (Na2SO4), potassium sulfate (K2SO4). copper(II) sulfate (CuSCfi), zinc sulfate (ZnSOty, or aluminum sulfate ( AtySOtyty

[0065] In some embodiments, the desiccant may be at least one of bentonite, clay, calcium chloride (CaCh), calcium oxide (CaO), lithium bromide (LiBr). sodium chloride (NaCl), plaster, magnesium oxide (MgO), sodium hydroxide (NaOH), and / or sulfuric acid (H2SO4).

[0066] In some embodiments, forming the slurry may include forming a dry mixture. The dry mixture may include the desiccant and a lignin. Forming the slurry may include forming an aqueous mixture. The aqueous mixture may include aqueous lignin, a laccase enzyme, optionally a silica source, optionally a colloidal silicate, and optionally a C2-C4 monoalcohol. Forming the slurry may include forming wet fibers by immersing the plurality of fibers into the aqueous mixture for a predetermined period of time. Forming the slurry may also include forming the slurry by combining the wet fibers with the dty' mixture, and mixing. In some embodiments, the silica source may be tetraethyl orthosilicate (TEOS) and / or colloidal silicate. The monoalcohol may be ethanol.

[0067] Referring now to FIG. 2A, an embodiment of a mould system (200) for curing the plurality of fibers is show n. The mould system may include a base portion (202) having one or more cavities (210) for receiving a slurry. The one or more cavities may be defined by a sidewall (212) and a bottom portion (214) each defining an interior surface of the cavity. The cavity may optionally include a shaping element (218). As shown in FIG. 2A, the shaping element (218) may be configured to mould the slurry into a substantially U-shaped structure. Those skilled in the art and informed by the teachings herein will appreciate that several other constructions of a shaping element may be utilized. For example the shaping element may form a solid rod.

[0068] Referring now to FIG. 2B, an exploded view of another embodiment of a mould system for curing the plurality of fibers is shown. When introducing the slurry into the mould, it is crucial that the slurry is introduced under pressure. Therefore, one way of ensuring that the slurry is introduced under pressure is to compress the slurry in a single direction within the mould with a removable top plate (230). As illustrated, the system includes a mould cavity defined within the base portion and a removable top plate that covers the cavity. To secure the top plate during the curing process, four screws may be positioned at each comer of the removable top plate (230), aligned with corresponding cylindrical cavities formed in the base portion (202). Dashed lines in FIG. 2B show how each screw is inserted vertically through the removable top plate and into the cavities to fasten the removable top plate securely. This arrangement enables the application of uniform pressure onto the slurry, ensuring consistent compaction and improved fiber distribution within the mould cavity during curing.

[0069] While this embodiment is shown using screws, other sealing arrangements are envisioned. For example, clamps, latches, or hydraulic or pneumatic locking mechanisms may be employed to secure the top plate to the mould body. Additionally, gaskets or O-rings may be positioned between the top plate and the mould cavity to enhance the seal and prevent slurry leakage during compression. In some variations, the entire mould system may be placed within an external press or vacuum chamber to apply uniform pressure externally, eliminating the need for internal fasteners altogether. These alternative configurations allow for flexibility in design while maintaining the desired pressurized environment for proper slurry curing.

[0070] Referring back to FIG. 2A, an alternative configuration for ensuring the slurry is introduced under pressure is shown. Instead of using a removable top plate, the mould system may include a cavity counterpart (240). The cavity counterpart may be configured to apply pressure to the slurry by being manually pressed into the cavity after the slurry is introduced. Those skilled in the art will appreciate that the cavity counterpart and removable top plate may be used in conjunction with each other.

[0071] In various aspects, a structural composition may be provided. Referring to FIGS. 3A and 3B, FIG. 3A depicts a three-dimensional view of an embodiment of the structural composition (300). The structural composition may include a plurality of relatively long, lignin-containing fibers (346) that are oriented in three dimensions. As illustrated in the coordinate system in FIG. 3A, these relatively long fibers may extend uniformly and orthogonally to one another. That is, the relatively long, lignin-containing fibers may be arranged so that each fiber is aligned along the x-, y-, or z-axis of the coordinate system. Shown in the section view of FIG. 3B, the structural composition may include a plurality of mediumlength (342) and relatively short (344), lignin-containing fibers that are positioned within volumes of space (340) between the relatively long fibers. These spaces may exist at submicron, micron, or millimeter scales, depending on the specific application or source material. The structural composition may be a homogeneous material with the plurality of fibers uniformly and / or randomly oriented. In some embodiments, the structural composition may also include salt desiccants evenly distributed in the structural composition. In some embodiments, the salt desiccants may be unevenly distributed in the structural composition.

[0072] Referring now to FIG. 3B, a cross-sectional view of another embodiment of a structural composition is shown. In this embodiment, the plurality of relatively long fibers are randomly oriented rather than uniformly constrained along any single axis. As illustrated, the fibers within the structural composition are distributed in multiple directions, resulting in a more isotropic arrangement. For example, in region (360). the fibers may extend along various angles relative to the x-, y-, and z-axes, providing a random, interwoven fiber network throughout the section. This random orientation can enhance the structural integrity' and multi-directional strength of the composition.

[0073] The relatively long, lignin-containing fibers may have an axial length longer than the medium and relatively short lignin-containing fibers. The medium lignin-containing fibers may have an axial length longer than the relatively short lignin-containing fibers. The relatively short lignin-containing fibers may have an axial length shorter than the relatively long and medium lignin-containing fibers.

[0074] The relatively long, lignin-containing fibers may have an axial length greater than the medium lignin-containing fibers and the relatively short, lignin-containing fibers. In some embodiments, the relatively long, lignin-containing fibers may have an axial length between about 20 mm to 2000 mm. The relatively long, lignin-containing fibers may have an axial length between about 20 mm to 1500 mm. The relatively long, lignin-containing fibers may have an axial length between about 50 mm to 1250 mm. The relatively long, lignin-containing fibers may have an axial length betw een about 100 mm to 1000 mm. The relatively long, lignincontaining fibers may have an axial length betw een about 200 mm to 800 mm. The relatively long, lignin-containing fibers may have an axial length between about 400 mm to 600 mm. The medium lignin-containing fibers may have an axial length greater than the relatively short, lignin-containing fibers and shorter than the relatively long, lignin-containing fibers. The medium lignin-containing fibers may have an axial length between about 10 mm to 20 mm. The medium lignin-containing fibers may have an axial length between about 11 mm to 19 mm. The medium lignin-containing fibers may have an axial length between about 12 mm to 18 mm. The medium lignin-containing fibers may have an axial length between about

[0075] 13 mm to 17 mm. The medium lignin-containing fibers may have an axial length between about

[0076] 14 mm to 16 mm.

[0077] The relatively short, lignin-containing fibers may have an axial length shorter than the medium lignin-containing fibers and the relatively long, lignin-containing fibers. The relatively short, lignin-containing fibers may have an axial length between about 0.1 mm to 1 mm. The relatively short, lignin-containing fibers may have an axial length between about 0.2 mm to 0.8 mm. The relatively short, lignin-containing fibers may have an axial length between about 0.3 mm to 0.7 mm. The relatively short, lignin-containing fibers may have an axial length between about 0.4 mm to 0.6 mm.

[0078] While FIGS. 3A and 3B show structural compositions that are substantially a rectangular prism, the structural composition may also be a molded structural composition (400) (see FIG. 4). As shown in FIG. 4, it may be desirable to mold the structural composition into cinder block structures which may then be used for construction purposes. The plurality of lignin-containing fibers are omitted in FIG. 4 for clarity; The molded structural composition may be achieved using the method described herein.

[0079] The disclosed structural composition may serve as a replacement for conventional structural materials, including wood-based products. One notable advantage is its ability' to minimize or eliminate the use of artificial, non-biological, or non-renewable components, making it a more sustainable alternative.

[0080] The versatility of the material enables a wide range of applications, depending on the additives and fiber architecture. For example, a composition with high lignin content and long fibers may be suitable for constructing durable, water-resistant structures such as boats. Similarly, lignin-rich formulations can be used to create compostable, moisture-resistant packaging. Incorporating sharp sand and aggregates, along with a helical fiber alignment, may yield a composite material capable of replacing concrete in certain architectural contexts. Additionally, the use of spray-on curing techniques allow for the fabrication of complex, three- dimensional wooden forms without the material waste associated with traditional milling methods. In general, where weight and material thinness are not critical constraints, the disclosed composition may offer a promising and sustainable alternative to conventional structural materials.

[0081] Some differences from conventional structural materials can be described as follows. Conventional paper uses the neutral sulfite semi-chemical process to extract nearly all lignin content from short-fiber wood chips. The resulting fibers are then randomly oriented in two dimensions, and the strength of the paper comes primarily from the friction between these short fibers. In contrast, the disclosed material differs because the feedstock for paper is typically limited to similar tree species and relies on extensive bleaching and delignification to ensure consistent product quality. The disclosed process, however, uses minimal chemical treatment and preserves much of the natural character of the raw material. Desired physical properties are instead achieved by combining different types of fibrous materials with varying fiber lengths. This heterogeneity in both the raw material and the resulting composition is a distinctive feature of the disclosed process and product.

[0082] Medium-density7fiberboard (MDF) is another existing product with some similarities. The primary raw material for MDF is sawdust, which consists of fibers with lengths generally in the sub-millimeter range. This extremely short fiber length results in a high surface area relative to the overall volume of the material, which dramatically increases the porosity of the finished board. High porosity, in turn, leads to significant water absorption and causes the material to swell when exposed to moisture. This swelling can be structurally catastrophic, resulting in dimensional instability, loss of strength, and degradation of the board’s mechanical integrity. Additionally, the very short fiber length results in low inherent structural strength, which is typically compensated for by using binders such as formaldehyde-based resins or similar alternatives. These binders are often derived from petroleum and can be toxic. In contrast, the disclosed material achieves enhanced structural performance by using longer, lignin-containing fibers that reduce overall porosity and improve dimensional stability, even in humid or wet conditions.

[0083] Oriented strand boards (OSB) also share certain similarities with MDF. The fabrication of OSB and plywood generally uses less formaldehyde or other adhesive agents than MDF and may incorporate laccase as an additional bonding agent. In these products, the fibers or strands are primarily oriented in two dimensions, similar to paper. To activate the bonding agents, including formaldehyde and the laccase enzyme, heat and pressure must be applied to promote adhesion to the fibers or cellulose. In contrast, the disclosed approach enables either anisotropic or isotropic fiber alignment in three dimensions, rather than limiting fiber orientation to one or two dimensions as in OSB and plywood. Glued-1 aminated timber (Glulam) also differs significantly from the disclosed approach. Glulam does not chemically homogenize the wood; therefore, to ensure product quality, only a very limited selection of tree species can be used. Any large imperfections must be cut away, resulting in wasted fibrous material. Furthermore, fiber alignment in Glulam is only possible in up to two dimensions.

[0084] Pressed carboard, such as that used for egg cartons, relies on a narrow range of short fiber lengths and functions similarly to thick paper, with strength primarily derived from the friction between fibers. Pressed cardboard products tend to swell and lose structural integrity when exposed to water. Additionally, pressed cardboard is typically formed through pressing, whereas in the disclosed approach, the fibers may be cast or spray -applied, providing greater flexibility in manufacturing and product performance.

[0085] Lastly, mineral-bonded wood wool boards are typically used for insulation applications. They are made from loosely packed wood wool that is bonded together with minerals or binding agents such as glue or resin. Because the fibers are loosely packed, these boards generally lack sufficient strength for structural applications. Additionally, the wood wool is produced by mechanically shaving or cutting wood logs, which results in non-continuous fiber bundles and does not allow for any selection based on fiber bundle quality. To compensate for the loose packing, the boards must be pressed to increase fiber density.

[0086] In contrast, the disclosed approach employs a milder caustic treatment that softens the fibers without fully disintegrating them, preserving longer, stronger fiber bundles. This method eliminates the need for extensive pressing to achieve the desired fiber density. As a result, the disclosed material can be cured and formed without heavy pressing equipment, enabling the production of much thicker products with unconventional shapes, rather than being limited to flat panels.

[0087] Furthermore, because the disclosed method uses a rolling mill instead of mechanical cutting or shaving, the fiber groups are separated along naturally weaker gaps between cellulose fiber bundles. This process is inherently self-selecting for stronger, more intact fiber bundles. Finally, the disclosed technique further reduces - and in some cases eliminates - the need for formaldehyde-based binders by filling the gaps between longer fibers with progressively shorter fibers. This gradation of fiber sizes creates a denser, more interlocked matrix that enhances strength and stability while minimizing voids. By decreasing or altogether eliminating the use of formaldehyde, the process lowers emissions of harmful volatile organic compounds (VOCs). and may improve environmental sustainability and the safety of the end product. Lastly, the present disclosure enables utilization of previously discarded portions of harvested trees, including branches, bark, and crown wood. Conventional forestry practices typically utilize only approximately 30% of a harvested tree for structural applications, with the remaining biomass often relegated to lower-value uses or waste. The present disclosure significantly increases the biomass yield from harvested trees by converting these underutilized portions into high-value structural materials, thereby maximizing the economic return from each tree while reducing forestry waste streams.

[0088] The following examples include data from experiments conducted to produce structural compositions. These examples are provided for illustrative purposes only and are not intended to limit the scope of the present disclosure. The specific values, materials, and conditions described are merely exemplary, and those skilled in the art will recognize that variations and modifications may be made without departing from the spirit and scope of the invention.

[0089] Example 1

[0090] In a first example, the composition included 3 grams of sulfate (comprising calcium sulfate and magnesium sulfate), 5 grams of colloidal silicate, 10 grams of lignin solution. 10 grams of lignin powder, 7.5 grams of silicate fibers, and 10 grams of laccase. The resultant structural material exhibited a post-cure weight of 23.3 grams, a post-cure thickness of 9.9 mm, and a density of 0.00148712 kg / m3. The tensile strength of the structural composition was measured at 63.5 N, with an ultimate compressive strength of 118.7 N.

[0091] Example 2

[0092] In a second example, the composition included 3 grams of sulfate (comprising calcium sulfate and magnesium sulfate), 10 grams of lignin solution, 5 grams of lignin powder, 7.5 grams of silicate fibers, and 10 grams of laccase. The resultant structural material exhibited a post-cure weight of 22.9 grams, a post-cure thickness of 8.6 mm, and a density of 0.001314 kg / m3. The tensile strength of the structural composition was measured at 22.9 N, with an ultimate compressive strength of 1907 N.

[0093] Various modifications may be made to the systems, methods, apparatus, mechanisms, techniques, and portions thereof described herein with respect to the various figures, such modifications being contemplated as being within the scope of the present disclosure. For example, while a specific order of steps or arrangement of functional elements is presented in the various embodiments described herein, various other orders / arrangements of steps or functional elements may be utilized within the context of the various embodiments. Further, while modifications to embodiments may be discussed individually, various embodiments may use multiple modifications contemporaneously or in sequence, compound modifications and the like.

[0094] Although various embodiments which incorporate the teachings of the present disclosure have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. Thus, while the foregoing is directed to various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. As such, the appropriate scope of the present disclosure is to be determined according to the claims.

Claims

What is claimed is:

1. A method for forming structured cellulosic material, comprising: providing a fibrous material containing lignin; performing partial cold caustic extraction in combination with use of a rolling mill on the fibrous material containing lignin to generate a plurality of fibers having a range of lengths and having a desired thickness or diameter, the range of lengths including longer length fibers, shorter length fibers, and intermediate length fibers; neutralizing and dry ing the plurality of fibers; forming a slurry by mixing a desiccant, a binder, and the plurality of fibers; introducing the slurry' into a mould while under pressure; and allowing the slurry' to at least partially cure in the mould, where incorporation of the shorter length fibers and intermediate length fibers creates a final structured material that has a reduced void space between fibers than a structured material utilizing only the longer length fibers.

2. The method of claim 1, wherein utilizing the rolling mill comprises rolling only a portion of the fibrous material containing lignin.

3. The method of any one of the preceding claims, wherein performing the partial cold caustic extraction in combination with use of a rolling mill comprises: soaking a fibrous material containing lignin in a sodium hydroxide solution at a temperature no more than 35°C for cold caustic extraction; and utilizing a rolling mill to form a plurality of fibers and to partially reduce the thickness of the fibrous material containing lignin.

4. The method of claim 3, wherein performing the partial cold caustic extraction in combination with use of a rolling mill comprises repeating the soaking of the fibrous material containing lignin in the sodium hydroxide solution and utilizing the rolling mill a predetermined number of repetitions.

5. The method of claim 4, wherein the predetermined number of repetitions is at least 10.

6. The method of claim 4, wherein the predetermined number of repetitions is 1-9.

7. The method of any one of claims 4-6, wherein the rolling mill is utilized multiple times following each soaking of the fibrous material containing lignin.

8. The method of any one of claims 3-7, wherein the sodium hydroxide solution includes sodium hydroxide at a concentration of at least 2.5% by weight of sodium hydroxide solution.

9. The method of claim 8, wherein the sodium hydroxide is present at a concentration of 18% to 22% by weight of sodium hydroxide solution.

10. The method of any one of the preceding claims, wherein neutralizing and drying the plurality of fibers comprises: neutralizing the plurality of fibers to a target pH using one or more acids; and removing at least some liquid absorbed by the plurality of fibers, by using a device to squeeze the plurality of fibers and / or allowing the plurality of fibers to air dry.

11. The method of claim 10, wherein the device is a rolling mill.

12. The method of any one claims 10 or 11. further comprising immersing the plurality of fibers in a mixture comprising a silica source and allowing the fibers to interact with the silica source.

13. The method of claim 12, wherein the silica source is at least one of tetraethyl orthosilicate (TEOS) and a colloidal silicate.

14. The method of any one of claims 12 or 13, further comprising drying the plurality of fibers after at least some of the silica source has been absorbed.

15. The method of any one of the preceding claims, further comprising sorting the plurality of fibers by length.

16. The method of claim 15, wherein sorting the plurality' of fibers by length includes sorting the plurality of fibers into three or more groups of fibers based group having a different range of fiber lengths.

17. The method of any one of claims 15 or 16, further comprising preparing a blend of fibers, the blend of fibers having a predetermined ratio of fibers of different lengths.

18. The method of any one of the preceding claims, wherein the desiccant is a sulfate.

19. The method of claim 18, wherein the sulfate is MgSCh and / or CaSC>4.

20. The method of any one of the preceding claims, wherein the desiccant is at least one of bentonite, clay, calcium chloride (CaCh), calcium oxide (CaO), lithium bromide (LiBr), sodium chloride (NaCl), plaster, magnesium oxide (MgO), sodium hydroxide (NaOH), or sulfuric acid (H2SO4).

21. The method of any one of the preceding claims, wherein forming the slurry comprises: forming a dry mixture comprising the desiccant and a lignin; forming an aqueous mixture comprising aqueous lignin, a laccase enzyme, optionally a silica source, optionally a colloidal silicate, and optionally a C2-C4 monoalcohol; forming wet fibers by immersing the plurality of fibers into the aqueous mixture for a predetermined period of time; and forming the slurry by combining the wet fibers with the dry mixture, and mixing.

22. The method of claim 21, wherein the silica source is tetraethyl orthosilicate (TEOS) and / or colloidal silicate, and wherein the C2-C4 monoalcohol is ethanol.

23. A structural composition, comprising: a plurality of relatively long, lignin-containing fibers, that are oriented in three dimensions; and a plurality of medium and relatively short, lignin-containing fibers, that are disposed in volumes of space between the relatively long, lignin-containing fibers.

24. The structural composition of claim 23, wherein the plurality of relatively long, lignincontaining fibers are substantially uniformly oriented in three dimensions.

25. The structural composition of any one of claims 23 or 24, wherein the plurality’ of relatively long, lignin-containing fibers are substantially randomly oriented in three dimensions.

26. The method of claim 4, wherein the rolling mill is utilized multiple times following each soaking of the fibrous material containing lignin.

27. The method of claim 3, wherein the sodium hydroxide solution includes sodium hydroxide at a concentration of at least 2.5% by weight of sodium hydroxide solution.

28. The method of claim 27, wherein the sodium hydroxide is present at a concentration of 18% to 22% by weight of sodium hydroxide solution.

29. The method of claim 1, wherein neutralizing and drying the plurality of fibers comprises: neutralizing the plurality of fibers to a target pH using one or more acids; and removing at least some liquid absorbed by the plurality of fibers, by using a device to squeeze the plurality of fibers and / or allowing the plurality of fibers to air dry .

30. The method of claim 29, wherein the device is a rolling mill.

31. The method of claim 29, further comprising immersing the plurality of fibers in a mixture comprising a silica source and allowing the fibers to interact with the silica source.

32. The method of claim 31, wherein the silica source is at least one of tetraethyl orthosilicate (TEOS) and a colloidal silicate.

33. The method of claim 31, further comprising drying the plurality of fibers after at least some of the silica source has been absorbed.

34. The method of claim 1, further comprising sorting the plurality of fibers by length.

35. The method of claim 34, wherein sorting the plurality of fibers by length includes sorting the plurality of fibers into three or more groups of fibers based group having a different range of fiber lengths.

36. The method of claim 34, further comprising preparing a blend of fibers, the blend of fibers having a predetermined ratio of fibers of different lengths.

37. The method of claim 1, wherein the desiccant is a sulfate.

38. The method of claim 37, wherein the sulfate is MgSCrt and / or CaSO-i.

39. The method of claim 1, wherein the desiccant is at least one of bentonite, clay, calcium chloride (CaCh), calcium oxide (CaO), lithium bromide (LiBr), sodium chloride (NaCl), plaster, magnesium oxide (MgO), sodium hydroxide (NaOH), or sulfuric acid (H2SO4).

40. The method of claim 1, wherein forming the slurry comprises: forming a dry mixture comprising the desiccant and a lignin; forming an aqueous mixture comprising aqueous lignin, a laccase enzyme, optionally a silica source, optionally a colloidal silicate, and optionally a C2-C4 monoalcohol; forming wet fibers by immersing the plurality of fibers into the aqueous mixture for a predetermined period of time; and forming the slurry by combining the wet fibers with the dry mixture, and mixing.

41. The method of claim 40, wherein the silica source is tetraethyl orthosilicate (TEOS) and / or colloidal silicate, and wherein the C2-C4 monoalcohol is ethanol.

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