Product based on magnesium oxide and continuous preparation method thereof

Abstract

A continuous process for forming a magnesium oxide-based product. The method includes preparing a feedstock, transferring the feedstock to a continuous curing process performed at elevated temperature and pressure, and drying the product of the continuous curing process. The method may also include a lamination process performed after drying or concurrently with curing. The continuous process reduces the cost and time associated with conventional processes.

Description

Technical Field

[0001] The present disclosure relates to magnesium oxide-based products, methods for preparing magnesium oxide-based products, and continuous preparation methods thereof. Background Art

[0002] Magnesium oxide (MgO)-based products have been applied in various industries due to their inherent water resistance, which provides advantages in applications where water-based damage can cause serious problems, and their excellent fire resistance. Summary of the Invention

[0003] It should be understood that this summary is not an extensive overview of the present disclosure. The summary is merely exemplary and non-limiting, and it is neither intended to identify key or important elements of the present disclosure nor to describe its scope. The sole purpose of the summary is to explain and illustrate certain concepts of the present disclosure as an introduction to the following complete and extensive detailed description.

[0004] The present disclosure relates to a method for preparing a magnesium oxide (MgO)-based product. The product includes, but is not limited to, an MgO core. The method includes an accelerated curing process that significantly shortens the time required to prepare the MgO-based product.

[0005] The present disclosure relates to a method that includes preparing a feedstock. In one aspect, the feedstock includes MgO, a salt, water, and a selected fiber. The fiber is selected from various fibers of different lengths, thicknesses, and materials, including but not limited to wood fiber, bamboo fiber, cellulose fiber, hemp fiber, natural fiber, pecan fiber, synthetic fiber, and any combination thereof. More than one fiber type can be used when selecting the fiber. The feedstock may also include additives. The present disclosure also relates to a method for preparing a variety of feedstocks with different compositions (such as different amounts of MgO, salt, water, fiber, etc. and different selections of fiber) to prepare an MgO core.

[0006] The present disclosure relates to a curing process that is accelerated compared to traditional curing processes. In one aspect, the curing process described herein is a continuous process that uses simultaneously elevated temperature and pressure. In one aspect, the temperature ranges from about 155°F up to about 310°F, and the pressure ranges from about 3 MPa up to about 13 MPa (per square inch), about 2 MPa up to about 4 MPa, or about 4 MPa up to about 10 MPa. The curing process can be carried out in about 3 minutes up to about 60 minutes and produces a product with a moisture content of about 4% up to about 20%. Depending on the combination of temperature, pressure, and moisture content in the product, the curing treatment time can vary. In one aspect, at a lower high temperature (e.g., about 155°F), the curing time can be below sixty minutes. In another aspect, at 180°F, the curing time can be 30 min, and at 250°F, the curing time can be 3 min, depending on the amount of water in the mixture. If there is too much water, it may cause bubbles (which may boil) and produce boil ripples on the board, which is undesirable.

[0007] The curing process can be carried out on or within various machines configured to provide high temperature and pressure, including but not limited to double belt presses. The MgO-based product (e.g., MgO core) coming out of the curing process can be subsequently dried to achieve a moisture content of about 4% up to about 13%. The thickness of the MgO-based product can range from about 3 mm up to about 15 mm. As a non-limiting example, the thickness of the MgO-based product can range from about 7 mm up to about 9 mm.

[0008] The present disclosure also relates to a process of applying one or more outer layers onto an MgO core. The outer layers include but are not limited to laminates, veneers, melamine, phenolic resin paper, melamine-impregnated phenolic resin paper, vinyl resins, digitally printed inks, polyurethane coatings, stain coatings, and other such materials. In one aspect, the process includes applying one or more outer layers to one or more sides of the MgO-based product. The process can be carried out after the drying process, or the outer layers can be applied simultaneously during the curing process. For the latter, one or more outer layers are placed on one or more sides of the MgO-based product before curing, and then they are applied or bonded to the MgO-based product while the curing process is taking place. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The features and components in the following figures are illustrated to emphasize the general principles of the present disclosure. For consistency and clarity, corresponding features and components in each figure can be labeled with matching reference numerals.

[0010] Figure 1Describe embodiments of a continuous method for preparing MgO products according to one or more example aspects of the present disclosure.

[0011] Figure 2 Describe embodiments of a raw material preparation process according to one or more example aspects of the present disclosure.

[0012] Figure 3 Describe embodiments of a curing process according to one or more example aspects of the present disclosure.

[0013] Figure 4 Describe embodiments of a drying process according to one or more example aspects of the present disclosure.

[0014] Figure 5 Describe embodiments of an outer layer application process according to one or more example aspects of the present disclosure.

[0015] Figures 6A-6B Illustrate embodiments of products according to one or more example aspects of the present disclosure that are free of powder ( Figure 6A ) and contain powder ( Figure 6B ).

[0016] Figure 7 Is a schematic diagram of an embodiment of a mechanical device used according to one or more example aspects of the present disclosure.

[0017] Figure 8 Illustrate a schematic diagram of an embodiment product according to one aspect of the present disclosure.

[0018] Figure 9 Illustrate a schematic diagram of an embodiment product according to one aspect of the present disclosure.

[0019] Figure 10 Illustrate embodiments of fibers that can be incorporated into products according to one aspect of the present disclosure.

[0020] Figure 11 Illustrate a magnified image of an embodiment fiber according to one aspect of the present disclosure. Include representative measurements of the embodiment fiber.

[0021] Figure 12 Illustrate a magnified image of an embodiment fiber according to one aspect of the present disclosure. Include representative measurements of the embodiment fiber.

[0022] Figure 13 Illustrate embodiments of products according to one aspect of the present disclosure. Detailed Description

[0023] It should be understood that the present disclosure is not limited to the compositions and methods described herein. It should also be understood that the terminology used herein is for the purpose of describing certain embodiments only and is not intended to be limiting, as the scope of the present disclosure is defined only by the appended claims.

[0024] I. Definitions

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Any compositions, methods, and materials similar or equivalent to those described herein may be used in the practice or testing of the present disclosure. All publications mentioned are hereby incorporated by reference in their entirety.

[0026] Unless otherwise defined, all percentage values of components used herein are given by weight.

[0027] In the context of describing the presently claimed disclosure (especially in the context of the claims), the terms "a", "an", "the", and similar references are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by the context.

[0028] Unless otherwise indicated herein, the numerical ranges recited herein are merely intended as a convenient method of referring individually to each separate value falling within the range, and each separate value is incorporated into the specification as if it were recited herein individually.

[0029] The term "about" is intended to describe values that are within approximately + / - 15% of the recited value; in other embodiments, the value may be within approximately + / - 10% of the recited value; in other embodiments, the value may be within approximately + / - 5% of the recited value; in other embodiments, the value may be within approximately + / - 2% of the recited value; in other embodiments, the value may be within approximately + / - 1% of the recited value. The foregoing ranges are intended to be clearly stated by context and do not imply further limitation. Unless otherwise indicated herein or clearly contradicted by the context, all methods described herein may be performed in any suitable order. Unless otherwise required, the use of any and all examples or instance language (e.g., "such as") provided herein is only intended to better illustrate the present disclosure and does not limit the scope of the present disclosure. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the present disclosure.

[0030] As used herein, "cement" refers to an adhesive substance that forms and solidifies into a hard mass through various hardening processes. The formation of cement can result in a "cement matrix" that may contain pores, voids, or gaps formed during the cement formation process. As a non-limiting example, the hardening process can include curing. The degree of solidification and hardening may depend on the level of hydration in the mixture undergoing the hardening process. The formation of cement can result from the reaction of mineral materials and salts in the presence of water. Such cement formation reactions can produce different yields, depending on reaction parameters known in the art, including but not limited to temperature, time, humidity, pressure, etc. As a non-limiting example, MgO, MgSO4, limestone, and other such materials can react in the presence of water to form cement.

[0031] As used herein, a "curing process" is a process during which chemical reactions occur to form cement, resulting in a product with desired qualities (e.g., harder, tougher, more stable, easier to handle in subsequent processes, etc.). In the presence of water, chemical reactions may occur between mineral materials and selected salts. Examples of mineral materials include but are not limited to MgO. Some salts can also be considered mineral materials. Some curing processes may require maintaining certain temperature, pressure, humidity levels, and other important process parameters.

[0032] As used herein, "moisture content" refers to the weight percentage of water in a test sample. Related test methods include drying a given sample in an oven. For example, the sample is dried in an oven at 212°F for approximately 24 hours. The sample is weighed at the start and end of the drying process and compared to calculate the percentage of the initial weight lost during drying. This is the moisture content of the original sample.

[0033] As used herein, "process parameters" can refer to process characteristics that have an impact on the quality of the final product. Such qualities can include moisture content, rigidity, tensile strength, water resistance, and other suitable qualities. Exemplary process parameters can include but are not limited to temperature, pressure, humidity, the order of mixing raw materials, and process time.

[0034] As used herein, "salt" refers to an ionic compound composed of two groups of ions with opposite charges (i.e., cations and anions). The cations and anions must be present in such a ratio that the total charge of the salt is zero (i.e., an equal balance between positive and negative charges). Salts can be used in the curing processes herein, where the salt can react with MgO in the presence of water. Non-limiting examples of salts include magnesium chloride (MgCl2), magnesium sulfate (MgSO4), and other such salts.

[0035] As used herein, "dimensional stability" refers to the ability of an MgO-based product to maintain its shape (e.g., flatness), rigidity, strength, and other such desired properties in the presence of stress sources. Stress sources include, but are not limited to, extreme temperatures, water contact, high pressures, etc. A product with poor dimensional stability may warp or fail in the presence of the above stress sources, while a product with good or high dimensional stability will maintain its shape (e.g., flatness), rigidity, strength, etc. in the presence of the stress sources.

[0036] As used herein, "yield" or "percent yield" refers to the ratio of the amount of actual product formed by a chemical reaction to the amount of product that could theoretically be formed in the reaction given the amount of reactants. The amount of product that could theoretically be formed can be calculated using the stoichiometric coefficients associated with the given reaction, while the amount of product actually formed can be measured. The general formula for "yield" or "percent yield" is

[0037]

[0038] II. Current Methods for Preparing Magnesium Oxide Products

[0039] Currently, MgO-based products are manufactured using a batch process, in which a wet or dry MgO composition is first placed in a mold and then cured through a reaction between MgO and a salt (e.g., magnesium chloride (MgCl2)). The total preparation time for all associated processes (e.g., curing, maintaining humidity, drying) is typically 36 hours to 156 hours, depending on the desired product. Throughout the curing time, the MgO product must remain in the mold so that cement is formed through the above reaction and to ensure that the product has the desired strength before being removed from the mold for further processing. The curing time monopolizes the use of these molds, resulting in a bottleneck in the overall MgO product forming method using the currently known batch processing methods in the art. In addition, the curing step requires a large amount of space in the factory to place the molds before the product can be removed.

[0040] Attempts have been made to accelerate the curing reaction of MgO compositions by increasing the temperature or pressure. However, water must be sufficient to facilitate the effective reaction of MgO and the selected salts. These attempts to increase pressure or temperature result in a decrease in the amount of water during the curing process, which produces undesirable products (e.g., brittle, non - moisture - resistant, etc.). Traditionally, the curing process using raw materials with a high water content (i.e., slurries) is carried out at low temperature and low pressure. To accelerate the curing of the slurry, water must be removed as quickly as possible during curing (i.e., at high temperature), which results in incomplete reactions and poor cement formation. Poor cement formation may result in brittle boards that may crack under pressure. In traditional methods using dry raw materials, the formation of cement during curing does not proceed adequately. This can be addressed by adding more fibers and using high pressure while maintaining a low temperature. If high temperature is used in a low - water - content method, air pockets may form due to water evaporation, reducing the strength and rigidity of the board. In both methods, the combination of high temperature and high pressure has not been successfully applied.

[0041] After the curing process, a drying process (i.e., allowing water to evaporate or escape from the panel) is typically carried out, which may be from 1 hour to 24 hours before the MgO core is ready for further steps, such as applying one or more outer layers (e.g., applying or adhering a top layer (e.g., laminate, decorative layer, wear - resistant layer, etc.) to the MgO core) by hot pressing. The drying step allows the manufacturer to control the moisture content desired for the final product, and more specifically, the moisture content desired for the MgO core. As a non - limiting example, controlling the desired moisture content is important when the MgO core must undergo additional processing. The additional processing may include adding one or more outer layers, including but not limited to laminates applied by high temperature and high pressure. As a non - limiting example, controlling the desired moisture content is important when the MgO core is used in applications that require high dimensional stability. Such applications may include but are not limited to floating floor applications using a locking system. Applications that do not require additional processing of the MgO core may not require control of the moisture content within a specific range, but still expect the moisture content to be reduced by drying.

[0042] Attempts have not been made to accelerate the individual steps (e.g., curing, drying, etc.) by increasing both temperature and pressure simultaneously. This is because increasing temperature or pressure has negative impacts, so it is not desirable to attempt to increase both simultaneously. However, the present disclosure outlines some benefits of such a change for traditional MgO methods.

[0043] III. Continuous Preparation Method of Magnesium Oxide Products

[0044] The present disclosure may be more readily understood by reference to the following detailed description, examples, drawings, and claims, as well as the description before and after them. However, before disclosing and describing the compositions, systems, and / or methods of the present invention, it should be understood that, unless otherwise specified, the present disclosure is not limited to the specific devices, systems, and / or methods disclosed, as these may of course vary. It should also be understood that the terms used herein are for the purpose of describing particular aspects only and are not intended to be limiting.

[0045] The present disclosure relates to a continuous method 1000 for preparing a magnesium oxide (MgO)-based product 100. In this regard, the exemplary process steps include, but are not limited to, preparing the raw materials for the MgO product (step 1100), curing (step 1200) the MgO product, drying (step 1300) the MgO product, and applying (step 1400) one or more outer layers to the MgO product, as Figure 1 shown. The last step includes adding one or more outer layers to the MgO product 100. Such outer layers include, but are not limited to, laminates, veneers, melamine, phenolic resin paper, melamine-impregnated phenolic resin paper, vinyl resins, digitally printed inks (with or without a primer coat), polyurethane coatings, dyed coatings, and other such materials. One or more outer layers may be applied during or after the curing process 1200 and / or after the drying process 1300.

[0046] The continuous method 1000 has significant improvements compared to the batch methods known in the art for preparing such products. In one aspect, the continuous method 1000 greatly reduces the time, space, and cost required to prepare MgO-based products, including the possibility of performing some of the above steps simultaneously. In these aspects, the time, space, and cost requirements are reduced by replacing batch processing steps on the order of hours or days with continuous variants of these steps on the order of minutes.

[0047] In one aspect, the continuous method 1000 includes preparing the raw materials (step 1100). In one aspect, preparing the raw materials includes selecting: MgO (step 1110), salts (step 1120), the amount of water (step 1130), a fiber component (step 1140), and any necessary additives (step 1150), as Figure 2 shown. The preparation of the raw materials does not necessarily have to be carried out in the order Figure 2 shown, but can be rearranged. That is, each component can be prepared at different times.

[0048] The composition of the raw material is selected (steps 1110-1150) to have the desired properties. Such properties include, but are not limited to, the desired reaction yield, the ideal water absorption (e.g., substantially all of the water is absorbed into the components of the raw material, as described below), the ability to be further processed, etc. In these aspects, the desired reaction yield can be obtained by selecting the ideal MgO formula (e.g., particle size) and salt, wherein the reaction of MgO and salt in the presence of water produces cement. In addition, the fiber composition can be selected to obtain the desired water absorption. In these aspects, the fiber composition may also affect the ability of the raw material to be further processed, such as applying one or more outer layers (step 1400). In addition, a specific fiber composition may affect and / or actively affect the strength of the MgO core (e.g., increase tensile strength). The composition of the raw material can also be selected to determine the desired properties of the final product 100. In this regard, the raw material can be prepared (step 1100) to provide a product 100 with properties, including, but not limited to, rigidity, water resistance (through absorption and expansion of the MgO product), surface smoothness and other such properties. These features and other features are discussed in detail below.

[0049] The selection of MgO (step 1110) and salt (step 1120) plays an important role in the whole method. The MgO and salt in the raw material will react chemically through the curing process (forming cement in the presence of water, discussed in more detail below) to give the final product 100 rigidity and durability. Other side reactions may also occur during the curing process, such as the reaction between MgO and water, which can form non-cement materials. Compared with the cement formation reaction, this type of side reaction may not be needed. In order to increase the yield of the cement formation reaction, MgO is usually in powder form (step 1110). Such a selection will make MgO react fully with salt in the presence of water during curing to form cement of sufficient strength to combine rigid plates together (maintain the shape of the plate). The salt can be selected from one or more of a variety of salts known in the art, including but not limited to magnesium chloride (MgCl2), magnesium sulfate (MgSO4), etc. (step 1120). In some embodiments, the salt can be magnesium phosphate.

[0050] In one aspect, the composition of the raw materials can be developed to include fine particles of MgO-based powder. Selecting finer MgO particles results in an increased rate of reaction of MgO with the salt in the presence of water during curing to form cement. This is partly due to the increased surface area of MgO. The increased reaction rate consumes more water during the curing process (e.g., see the chemical reaction equations above), leaving less water in the cement. The increased reaction rate and water consumption are desirable in this continuous process to accelerate curing while minimizing the remaining water after the curing process, which will be discussed in detail below. Also, using MgO-based powder with increased reactivity (e.g., fine particles) results in a higher cement yield in the curing reaction, thereby producing a stronger product 100. Although MgO-based powder with lower reactivity (i.e., MgO with reduced reactivity (i.e., larger particles)) can be used, the cement formed will be weaker and there will be excess water after the accelerated curing process (step 1200). The remaining excess water will impede the subsequent steps of the continuous process and will also produce a finished product with less desirable properties. Additionally, the increased reaction rate is beneficial for increasing the yield of cement in product 100. In these aspects, the reaction yield between MgO and the salt in the presence of water can range from about 50% up to about 95%. In certain aspects, a yield of at least about 80% is preferred. As non-limiting examples, particles less than 50 microns, less than 75 microns, and less than 150 microns can be used as the MgO-based powder.

[0051] In addition, fine powders without MgO can be used in the raw materials to reduce the porosity of the final product and improve its water resistance. As described below, the continuous curing process can benefit from an increased fiber content. However, the increased fibers can cause more expansion and contraction of the fibers, creating more space / pores between the fibers. The fine powders can be prepared using materials that do not react with water - including but not limited to natural fibers (e.g., wood, bamboo, etc.), additives (CaCO3, talc, perlite, fly ash, plastics, etc.), and other such materials - to reduce porosity by filling the spaces (i.e., acting as fillers) between fibers of various sizes. As can be seen in Figure 6A (without powder) and 6B (with powder), the use of additional powder can reduce the porosity of the boards in embodiments using large fibers. As the porosity is reduced, the final product 100 includes fewer open pores for water to enter the product 100.

[0052] Water can be added in various amounts, depending on process requirements (step 1130). The presence of water in the raw materials causes a cement formation reaction between MgO and the salts. As a non-limiting example, water can be added until the desired reactivity level is reached. This can be measured by using x-ray diffraction to analyze the amount of unreacted MgO remaining in product 100, as described herein. In some instances, water can be added until only 5% of the MgO in the raw materials remains unreacted in product 100. In subsequent steps of method 1000, substantially most of the water must be removed to facilitate additional process steps (e.g., applying one or more outer layers 1400), as described below.

[0053] The amount of water prepared is based on the amount of water that will be absorbed by other components of the raw materials, which in turn depends largely on the fiber component, as described below. Water absorbency is necessary to ensure proper cement hydration and crystal growth. In these respects, no excess water remains in the raw materials after absorption by the fiber component. The raw materials described herein do not suspend in water or have any appreciable excess water as would be expected in a slurry used in a conventional wet batch process. Instead, the raw materials of the present disclosure more closely resemble a dry powder with unique powdery fibers that can be spread onto a surface. Although the raw materials may have a slight, detectable moisture when touched, they do not visibly contain a slurry.

[0054] In addition, the amount of water used in the raw materials can affect the chemical and physical processes during the various steps after the raw materials are prepared. During curing (step 1200), water is necessary for the cement-forming reaction between MgO and the salt. The water is removed during curing (i.e., by chemical reaction, evaporation, or pressure) or after curing (e.g., evaporation during drying or under pressure) (step 1300) in order to perform subsequent processing (e.g., applying one or more outer layers 1400). However, as described above, the amount of water added to the raw materials before the curing step ensures that all or substantially all of the added water is absorbed by the other components of the raw materials (i.e., there is no excess water), as described below. In these respects, water is added to the raw materials in an amount such that the other components absorb the water without any water remaining (i.e., the raw materials do not form a slurry). The amount of water allows the cement reaction during curing 1200 to proceed sufficiently to bond the fibers present in the raw materials without producing a slurry. In this regard, the raw materials can be described as dry rather than wet. In some aspects, the amount of water required can be determined based on how much water is needed to cause a certain amount of MgO in the raw materials to react. In such an aspect, the level of unreacted MgO in product 100 is determined by x-ray diffraction (XRD) analysis as is known in the art. If there is still unreacted MgO in product 100, additional water can be added to the raw material formulation. The dry raw materials facilitate further processing. As a non-limiting example, the dry raw materials can prevent the formation of bubbles in processes involving high temperatures (e.g., hot pressing), while wet raw materials (i.e., slurries) may cause bubble formation due to the evaporation of excess water. In addition, the elevated water content in the final product 100 resulting from the presence of excess water in the raw materials reduces the rigidity. The reduced rigidity may cause product 100 to fail in its applications (e.g., flooring, decoration, and other such applications). The example moisture contents required after the different stages of the continuous method 1000 are discussed below.

[0055] As described above, the water is absorbed by the various components of the raw materials. In this regard, about 20 wt% to about 50 wt% of water can be added to the raw materials. The water can be absorbed by the fibers. In this regard, the fibers are selected to retain a sufficient amount of water to facilitate an effective curing reaction during the curing process 1200 and to release the water sufficiently at a later stage (e.g., drying 1300), where elevated water content can result in undesirable properties (e.g., during drying 1300). For some outer layer application steps 1400, a high or even moderate water content / water retention is not required. In these respects, it is desirable to configure the MgO product 100 to have a low moisture content value before receiving the top layer. The low moisture content allows the water to leave the outer layer and be absorbed into the MgO product during the application process (e.g., hot pressing, etc.), thereby promoting a stronger bond formation between the MgO core and the outer layer (e.g., laminate, veneer, etc.).

[0056] It also includes adding a fiber component to the raw materials during raw material preparation (step 1140). In one aspect, the selection of fibers in the raw materials is important for obtaining the desired properties of the final MgO product 100, as described above. The fibers can be selected from a variety of natural and synthetic fibers. The selection of fiber length and coarseness is also important. As a non-limiting example, long and thin fibers increase the rigidity of the final product 100 and reduce the water absorption rate, while also providing some flexibility. Due to the inclusion of an increased proportion of individual fiber strands, long and thin fibers can provide increased rigidity, including but not limited to tensile strength. Such fiber strands may be more likely to tangle with each other. This tangling forms a network structure within the cement matrix formed during the curing process 1200. This combination provides increased tensile strength. As described herein, long and thin fibers can also be better encapsulated by the cement formed during the curing process 1200. This may provide a final product 100 that is more resistant to swelling and cracking. Encapsulating the fibers completely with cement prevents these fibers from further absorbing water in the product 100.

[0057] In another exemplary aspect, short and thin fibers also reduce the water absorption rate of the final product 100. Short and thin fibers are easily compacted. This allows for a reduction in porosity and an increase in water resistance. Coarse fibers of different lengths result in a high water absorption rate for the product 100. Such fibers may lead to an increased porosity due to their larger fiber size, which, as described above, can be addressed by using fine particles to fill these spaces.

[0058] As described above, fiber selection determines not only the important properties of the final product 100 but also the absorption characteristics of the raw materials. In one exemplary aspect, long and thin fibers provide a low water absorption rate for the raw materials. In one exemplary aspect, short and thin fibers provide a high water absorption rate for the raw materials. In one exemplary aspect, coarse fibers of different lengths can provide a high water absorption rate and uniformity during raw material preparation. The absorption characteristics of the fibers in the raw materials are important for both efficient curing 1200 and subsequent processing (e.g., applying one or more outer layers 1400). In this regard, the fibers are required to have an initial water absorption rate for the cement formation reaction between MgO and salts to occur in the presence of water for curing. The initial water absorption rate can be provided by short and thin fibers or coarse fibers of different lengths. In one aspect, as described herein, a lower water absorption rate of long and thin fibers may be required for subsequent processing (e.g., applying one or more outer layers 1400). In these aspects, different combinations of fiber morphologies can be selected to provide an optimized array of process parameters to the raw materials. In certain aspects, the fibers can additionally be pretreated to change their absorption characteristics. As a non-limiting example, the fibers can be soaked in a hydrogen peroxide solution to reduce the water absorption rate of the final product 100. Soaking the fibers in a hydrogen peroxide solution or other similar chemical solutions will digest the cellulose component of the fibers, ultimately reducing the water absorption rate and swelling.

[0059] Fiber selection may also affect the flexural strength of the finished product 100. As a non-limiting example, fibers of lower coarseness (including but not limited to fine fibers) may provide improved flexibility to the product 100. Such fibers may also be more easily encapsulated by the cement crystals formed during the curing process 1200. As a non-limiting example, crystal formation may also depend on the ratio of components in the liquid mixture, as described herein. In such an example, crystals may be more easily formed using a liquid mixture comprising a water:MgO ratio of 0.3 to 1 or a water-salt-solution:MgO ratio of 0.40 to 1.5. In some examples, crystals may be more easily formed using a liquid mixture comprising a water:MgO ratio of 0.3 to 1 or a water-salt-solution:MgO ratio of 0.45 to 1.43, and any other suitable ratio therebetween. Cement crystals may form dendritic cement crystals. Such fibers may also fill the gaps in the cement matrix. As described herein, the cement matrix is formed during the curing process 1200. The matrix includes but is not limited to pores or gaps, cement crystals, and other related components.

[0060] As a non-limiting example, the raw materials may use only long and thin fibers. Long and thin fibers may include softwoods, including but not limited to pine, poplar, etc. Such a composition may provide a final product 100 with enhanced flexibility and strength. This combination of properties (i.e., flexibility and strength) may be beneficial for the product 100 to be used in "click" or "lock" profile applications. Such applications include but are not limited to products 100 for floor installation, where individual panels snap and lock into place. In another non-limiting example, the raw materials may use mostly long and thin fibers, while the remaining fibers include different morphologies. In some examples, conversely, only thick and short fibers or thick and long fibers or mostly such fibers may be used. Such fibers may be from hardwoods, including but not limited to oak. In such an example, the product 100 may be used in applications that do not require flexibility.

[0061] On the other hand, fibers not bound to lignin can also be used. As a non-limiting example, fibers bound to lignin can include fibrous structures. Such structures may have undergone less processing compared to fibers not bound to lignin. One such example may include a piece of untreated wood. In such an example, the wood may contain fibers bound to an increased amount of lignin relative to treated fibers not bound to lignin. Incorporating fibers with less lignin can produce products with better properties (including but not limited to tensile strength). Fibers not bound to lignin may have a higher volume of actual fibers (i.e., non-lignin). When added to product 100, this allows such fibers to provide more fibers per unit area. The increased fibers per unit area can provide enhanced flexibility to the final product 100. As a non-limiting example, fiber values per unit area of about 1 up to about 10 g / in 2 , about 2 up to about 9 g / in 2 , about 3 up to about 8 g / in 2 , about 4 up to about 7 g / in 2 , and about 5 up to about 6 g / in 2 can be used. In one example, the fibers per unit area can be from 2 g / in 2 up to 5 g / in 2 .

[0062] The fiber components can include, but are not limited to, wood fibers, bamboo fibers, cellulose fibers, other natural fibers (e.g., hemp fibers, pecan fibers), synthetic fibers (e.g., acrylic, polypropylene (PP), polyethylene terephthalate (PET)), etc. Some fibers may need to be avoided. Fibers rich in lignin, hemicellulose, sugars, fatty acids, or other organic impurities may impede the setting time of cement and crystal growth. As mentioned above, the fiber components added before curing help retain moisture during curing. In one aspect, the continuous curing process requires a higher fiber content than traditional curing setting, so more fibers are needed in the prepared raw materials. The continuous curing process is accelerated with increasing temperature and pressure. As mentioned above, the continuous curing process also uses raw materials without excessive water content. Such a combination can lead to a reduction in cement formation. By adding more fibers to the raw materials, the increased fiber content can effectively bond together regardless of the level of cement formation reduction. Despite the reduced amount of cement formed, the increased fiber content provides an effective binder to form an MgO core with the necessary properties. Increasing the fiber content can form an MgO core with rigidity, strength, and other such desired properties that are not expected in traditional curing due to a lower level of cement formation caused by a smaller amount of excess water and time. In one aspect, the fiber selection of the raw materials also affects the surface smoothness of the MgO product. Long fibers may result in reduced smoothness, while short fibers may result in increased smoothness. In some aspects, surface smoothness may be required for further processing, including but not limited to adding a top layer. In some instances, short fibers or shorter fibers can be used closer to the surface of the MgO core to obtain a smoother surface, while a mixture of short fibers or long fibers can be used in the middle and away from the surface, and vice versa. In some instances, a mixture of short fibers and long fibers can be used throughout the MgO core, with more short fibers present at the surface and nearby, and more long fibers present in the middle, and vice versa.

[0063] In some instances, the fibers can also be rinsed. Rinsing the fibers may clean them or alter their structure. This may promote the bonding of the fibers to the cement. The fibers can be rinsed with hot or cold liquids. Such liquids can include, but are not limited to, water, alkaline solutions, sodium hypochlorite solutions, sodium hydroxide solutions, and other such known fiber cleaners.

[0064] The composition of the raw materials may also include additives and other such substances known in the art (step 1150). The additives help to provide additional desired properties to the MgO core. As non-limiting examples, the additives can evenly disperse the particles in the core, improve the water resistance of the board by encapsulating unreacted MgO particles, help molecules (such as water, salts, minerals, etc.) move more freely during the curing stage and reduce the risk of cracking, fill the voids in the core and reduce the porosity, improve the bonding between the fibers, etc. The additives may include but are not limited to latex, phosphoric acid, perlite, CaCO3, talc, synthetic fibers, polymers, and other such substances.

[0065] The dimensional stability of the MgO product 100 can be measured in various ways. As a non-limiting example, according to the Window and Door Manufacturers Association Test Method (WDMA T.M.) 2-15 test standard, measuring the linear growth after immersing the product 100 in water under ambient conditions for about 24 hours can be called the swello-meter test. In this test, it may be desirable to achieve an initial expansion of less than about 0.80% up to about 0.60%, which indicates the presence of sufficient water. On the other hand, it may be desirable to achieve an initial expansion of less than about 0.50%. In this regard, the level of the initial expansion provides sufficient water for at least 95% of the MgO in the raw materials to react in the curing reaction (i.e., 5% unreacted MgO). In this regard, the fibers can be selected to achieve this initial expansion. As described herein, fibers with different properties (such as length, thickness, material, etc.) have different water absorptions. As non-limiting examples, fibers that can absorb about 60% to about 400% of their own weight of water can be used. As described herein, this absorption rate can enable the fibers to effectively bond with the cement formed during curing. Insufficient absorption (e.g., <60%) may result in the formation of a porous cement matrix during curing and expose the fibers. Excessive absorption (e.g., >400%) can cause the fibers to expand excessively and be difficult to encapsulate in the final product 100. Lack of encapsulation may cause the fibers to absorb more water over time. This may cause the product 100 to crack or expand.

[0066] In one aspect, although the length and thickness of the fibers used can be important factors, the surface area of the fibers (sometimes referred to as the particle size) also plays an important role. As non-limiting examples, fibers with a surface area of less than about 0.4 mm can be used. In another exemplary aspect, fibers with a surface area of less than about 0.2 mm can be used.

[0067] In another aspect, it is desirable to use fibers having a range of surface area dimensions, as both large (e.g., greater length to increase strength) and small (e.g., short and thin to occupy space / fill voids) dimensions are needed to meet certain properties of the MgO product. In another aspect, a combination of fiber surface areas can be used in a single batch. As a non-limiting example, a fiber blend can be used that includes no more than about 70 wt% of fibers having a surface area of about 1 mm, about 20 wt% to about 70 wt% of fibers having a surface area of about 0.45 mm up to about 0.7 mm, and about 4 wt% up to about 15 wt% of fibers having a surface area less than 0.1 mm. In most cases, fibers having a surface area greater than 4 mm should not be included.

[0068] As with the surface area values, the length and coarseness of the fibers can also vary, including within a single batch. As a non-limiting example, fibers having a length of about 0.1 mm up to about 4 mm can be used. In some instances, fibers having a coarseness of about 0.02 mm up to about 0.05 mm can be used. In one exemplary aspect, according to the present disclosure, fibers having the desired properties include, but are not limited to, wood fibers, hemp fibers, rice fibers, cellulose fibers, pecan fibers, synthetic fibers, and other such fibers known in the art.

[0069] After preparing the raw materials (step 1100), the curing process (1200) can be initiated. In one aspect, the curing process 1200 begins when the components of the raw materials come into contact with each other. More specifically, when MgO and the salt come into contact in the presence of water, the curing process begins (step 1210). In this regard, MgO and the salt can undergo a curing reaction in the presence of water to form a cement. In one aspect, to ensure good distribution of all materials, the water and the salt can first be mixed together. Then the water and salt solution can be added to the fibers. If additives are to be used, they can be added to the fibers before introducing the water and salt solution. In some instances, the additives can also be added at other steps in the raw material preparation. The fibers that have absorbed the water and salt solution can then be mixed with the MgO-based powder. After adding and mixing the MgO-based powder, the raw materials can be maintained at the desired temperature and humidity conditions (e.g., 60 °C and 70% relative humidity) for about 30 min. This can help initiate the chemical reaction and achieve the desired cement formation. At this stage, some of the water will start to be consumed through the cement formation reaction of MgO and the salt. This consumption will make the raw materials drier and reduce the risk of air pockets appearing during the curing stage.

[0070] As a non-limiting example, it may be advantageous to first mix all of the dry materials before combining them with the liquid. This can reduce the water content in the final feedstock, as the dry materials can be continuously added to the liquid until the water content is significantly reduced. It may be advantageous to add the mixed dry materials to the liquid rather than adding the liquid to the mixed dry materials. As described herein, the liquid can include a solution of water and salt.

[0071] Once mixed, the feedstock can be spread on a surface 10 (e.g., a conveyor belt, as Figure 9 shown) (1220). The surface 10 can include a mold or a flat surface for forming the MgO product. In one aspect, the spread feedstock is relatively dry when spread based on the absorption of moisture by the components and the progress of the curing reaction. Once spread on the surface, a combination of high temperature and high pressure is used to accelerate the curing process (step 1230). In this regard, compared to the prior art range of about 75°F up to about 150°F, the high temperature can include a temperature range of about 160°F up to about 300°F. In some examples, the high temperature range can be 155°F to 310°F. In certain examples, the high temperature range can be about 180°F up to about 210°F. Additionally, the high pressure can include a pressure of about 4 MPa up to about 10 MPa per square inch. In some examples, the high pressure range can be about 2 MPa up to about 13 Mpa, or about 2 MPa up to about 4 MPa. Regardless of the known ranges, the MgO product has never been cured using both high temperature and high pressure levels simultaneously. Traditional methods focus on not increasing or increasing little pressure (i.e., processes using high water content feedstock rather than low water content feedstock) and low temperature (i.e., wet and dry MgO board preparation). In one aspect, the high temperature and high pressure can accelerate the chemical reaction, removing water from the feedstock faster while still retaining enough water to further promote curing. In one aspect, the fibers described herein allow the feedstock to maintain sufficient water content to achieve the desired reaction yield (i.e., MgO and salt react in the presence of water to form cement), while minimizing any remaining amount of unnecessary water after curing.

[0072] As described above, the use of fine MgO particles may result in increased reaction rates and yields due to the increased surface area. In this regard, the increased reaction rate helps to reduce the amount of time required for curing. Shortening the curing time enables the curing process to be continuous. In this regard, the reaction yield can range from about 50% up to about 80%. In this regard, simultaneously raising the temperature and pressure enables the curing process 1200 to proceed more rapidly than prior art curing processes for MgO products. High temperatures increase the reaction rate due to effects such as (but not limited to) endothermic reactions, LeChatelier’s principle, etc. However, the temperature cannot be raised excessively because this may result in the formation of amorphous cement. The formation of amorphous is undesirable and may weaken the board. Thus, while it is possible to expose the curing stock to temperatures above 310°F, it is not recommended in order to avoid the formation of amorphous cement. In some aspects, exposing the curing stock to temperatures above 300°F may result in the formation of amorphous cement.

[0073] High pressure is desirable to increase heat transfer from the ambient high temperature to the middle of the product. This will provide a more efficient reaction as the entire board will receive the high temperature more quickly. In this regard, the curing process 1200 conducted at high temperature and high pressure can be carried out in about 3 minutes up to about 10 minutes, compared to the curing times of 6 hours to 72 hours for batch methods known in the art. Additional curing times and their considerations are described herein. In these aspects, the stock in the continuous method described herein can be demolded (i.e., removed from its mold) after about 3 minutes up to about 10 minutes. This is very different from traditional batch methods where the MgO material must remain in the mold for a long period of time. Depending on the combination of temperature, pressure, and water content in the product, the curing treatment time can vary. In one aspect, at a lower high temperature (e.g., about 155°F), the curing time can be less than sixty minutes. In another aspect, at 180°F, the curing time can be 30 minutes, while at 250°F, the curing time can be 3 minutes, depending on how much water is in the mixture. As a non-limiting example, curing can be carried out at about 4 MPa and about 200°F for about 10 minutes. As a further non-limiting example, curing can be carried out at about 6 MPa and about 270°F for about 5 minutes. In another aspect, as described herein, using a stock with a low water content also results in a product from the curing process 1200 having a low water content. This enables the subsequent drying process to proceed more rapidly. Additionally, while most of the curing occurs during the curing process where high temperature and pressure are applied, smaller scale curing can occur after this exposure (e.g., during drying 1300), which can also result in a reduced water content in the final product while also increasing its strength. However, if there is too much water, bubbles (which may boil) will form and produce undesirable boiling ripples on the board.

[0074] As described above, according to one aspect of the present invention, the raw material can be placed on a surface after mixing and exposed to high temperature and high pressure during the curing portion (step 1200) of the continuous process. The surface can include a moving belt. In this regard, the moving belt can move the raw material through a machine that provides the high temperature and high pressure required to accelerate the curing process (step 1230). The machine can be selected from various machines capable of providing high temperature and high pressure to enable continuous flow of the raw material, including but not limited to a continuous double belt press. Other machines capable of applying pressure and heat can also be used.

[0075] As the raw material moves through the machine (see Figure 7 ), the moisture content of the reactive raw material decreases during the curing process 1200. During the curing process (step 1200), especially during the application of high temperature and high pressure (step 1230), the moisture content can decrease, where some water is consumed due to curing, and an additional portion of the moisture / water can also evaporate due to the high temperature and high pressure of the machine. In this regard, the moisture content can be reduced to the level required for subsequent processes (e.g., drying 1300, applying one or more outer layers 1400). In this regard, after applying high temperature and high pressure 1230 during the curing process 1200, the MgO product can contain from about 4% to about 20% moisture content, depending on time, applied temperature, and pressure. In this regard, the MgO product can contain from about 5% to about 12% moisture content. In some instances, after applying high temperature and high pressure 1230 during the curing process 1200, the MgO product can contain from about 2% to about 20% moisture content, depending on time, applied temperature, and pressure. In some aspects, the MgO product produced by the methods described herein can contain from about 2% to about 6% moisture content.

[0076] Traditional slurry (i.e., wet) batch methods (i.e., placing the raw materials on the mold surface without exposure to high temperature and pressure) contain a relatively high moisture content after curing. For example, traditional slurry batch methods (having an excessive water content in the raw materials) can provide a product with a moisture content of 10% up to 25% after curing. Traditional dry batch methods (using raw materials without excess moisture) can provide a product with a moisture content of 7% up to 20% after curing. In this regard, traditional batch methods remove the product with these moisture contents from the mold and then send the product for subsequent processing steps, such as drying, at the end of curing (i.e., when the product reaches the said moisture content range). These traditional slurry batch methods can require 6 hours up to 24 hours of curing for high moisture raw material methods and 12 hours up to 72 hours for low moisture raw material methods to reach this moisture content. According to one aspect of the present disclosure, when high temperature and pressure are applied to the raw materials during curing (step 1230), the curing process 1200 can achieve a desired moisture content of about 5% up to about 12% in less than about 1 hour. In additional examples, the desired moisture content can be achieved within a curing time of about 10 minutes up to about 60 minutes, about 3 minutes up to about 60 minutes, about 10 minutes up to about 50 minutes, and about 3 minutes up to about 10 minutes. The curing time can depend on the temperature used during curing and the amount of water present in the raw material composition. As a non - limiting example, curing carried out at 180°F can be done in about 30 min. In another non - limiting example, curing carried out at 250°F can be done in about 3 min. In both of these examples, the required curing time may depend on how much water is present in the raw material composition. In such examples, compositions with a high water content may form bubbles during curing due to water evaporation, which can lead to ripples or other defects in the final product 100.

[0077] In some aspects, the use of a high-temperature accelerated curing process 1200 may result in unreacted salts in the hardened MgO product 100. Other factors may also cause unreacted salts, such as low mixing efficiency, which fails to evenly distribute the reactants throughout the raw materials. The salts may absorb moisture in the final product 100, resulting in reduced rigidity. In other aspects, the accelerated curing process 1200 may produce a higher percentage of amorphous phase reaction products. The slower curing process employed in traditional batch methods may result in a lower percentage of amorphous phase reaction products and a higher percentage of crystalline phase reaction products. In these aspects, a higher level of crystalline products and a lower level of amorphous products result in increased product rigidity. Thus, the accelerated method may lead to lower rigidity. To counteract the lower rigidity due to hygroscopic salts and lower crystalline reaction products, the final product 100 may be made to have a greater thickness 110 to accommodate the reduced rigidity. In these aspects, to address the potential issue of reduced rigidity, the thickness 110 of the product 100 cured in the accelerated curing process may be about 5% to about 15% thicker than that of the product 100 made with a non-accelerated curing process.

[0078] As an example, using a flexure test in accordance with ASTM 1037, products with a thickness of about 6 mm and about 7 mm manufactured by prior art batch methods produced static flexure test results of about 75 lbf and about 100 lbf, respectively. In some examples, products 100 of similar dimensions of about 6 mm and about 8 mm made by the continuous method 1000 of the present disclosure produced static flexure test results of about 55 lbf and about 85 lbf, respectively. By increasing the thickness of the products 100 of the continuous method by 10 - 15%, comparable static flexure test results can be produced compared to prior art batch methods. For example, a 7 mm product 100 prepared by the continuous method produced a static flexure test result of 85 lbf, and a 9 mm product 100 prepared by the continuous method produced a static flexure test result of 110 lbf. Additionally, adding 2 - 5 wt% more fibers to the overall mixture can achieve the same effect. Although more materials may be used to manufacture the product, the increased associated cost is offset by a significant reduction in the processing time during curing 1200.

[0079] As another example, the present disclosure relates to various raw material compositions for preparing product 100. Other examples of the compositions may result in product 100 having a tensile strength that is stronger or weaker than the examples discussed above. As an example, the present disclosure relates to a plate having a thickness of about 5 mm and capable of withstanding an 80 lbf static bend test. In this example, increasing the thickness of product 100 also increases the tensile strength. In this example, product 100 using the same composition is capable of withstanding 110 lbf in a static bend test when prepared to a thickness of about 6 mm. A plate of about 7 mm may be capable of withstanding 120 lbf in a static bend test. An 80 lbf static bend test result may be advantageous for exemplary applications. As an example, the application of paper layers to the top and bottom of product 100 may require a minimum static bend test result of 80 lbf to balance the paper layers (i.e., counteract dimensional instability or the tendency of the paper to shrink and cause the plate to curl).

[0080] In other examples, compared to prior art products, an increased thickness may not be required to maintain the quality of the final product 100. In such examples, the fiber composition and concentration may be varied rather than the final product thickness 100 to provide the same or improved quality as prior art products. In such examples, quality includes tensile strength, flexibility, etc. In such examples, as described herein, by using from about 20% to about 40% by weight of long and thin fibers in the raw materials, the quality of the final product 100 can be maintained compared to prior art products of the same thickness. Such fibers may include lengths up to about 4 mm. Such fibers may also be fibrillated. In such examples, the plate thickness may still be increased. This will increase the strength of the final product 100 compared to prior art products using a batch curing method.

[0081] As described above, the conventional curing time of about 6 to about 24 hours can be reduced to about 3 minutes to about 10 minutes or other such curing times described herein. The use of the continuous curing process 1200 also eliminates the storage space required by conventional methods, i.e., storing the raw materials in a mold during the curing process.

[0082] After curing 1200, product 100 can be removed from the mold (step 1240) and cut to the desired size (step 1250), and then transferred to the drying process 1300, as Figure 7As shown. In other aspects, the product 100 can be cut within the mold and then removed. In one aspect, the moisture content of the product can be maintained first after leaving the curing process 1200 and before drying 1300. In this regard, the product can be placed on a tray or some other storage device and left for a specified period of time before drying. Maintaining the moisture content after the accelerated curing process 1200 allows the product 100 to reach the desired strength by continuing with additional curing. In this regard, the moisture content can be maintained for several hours or days. This additional curing is carried out without high pressure and high temperature.

[0083] However, in some aspects of the present invention, the additional time between the curing and drying processes is not necessary for a continuous method. For example, the product 100 after curing can be immediately transferred to a drying device (e.g., a drying rack) after leaving the curing process (step 1310). In this regard, the moisture content can then be reduced to the desired level during the drying process. The drying process can include placing the product in an oven. The drying process can include placing the product on a conveyor (e.g., a belt or rack) and moving it through a tunnel. The temperature and humidity within the tunnel can be raised or lowered to achieve the desired moisture content when the product 100 comes out. In this regard, drying can be carried out by applying a high temperature for a period of time (step 1320). The high temperature range can be from about 140°F to about 390°F. Although using a higher high temperature (e.g., above 300°F) during curing can result in the formation of amorphous cement and should therefore be avoided, a higher high temperature is acceptable during drying. Most of the cement formation occurs during the curing process, resulting in a reduced likelihood of forming amorphous cement during the drying process. In this regard, drying can be carried out for about 30 min to about 4 h. As a non-limiting example, drying can be carried out at about 320°F for about 30 minutes, at about 150°F for about 4 h, and any combination thereof. Drying is carried out until the desired moisture content level is reached (step 1330). In this regard, depending on the desired use of the board 100, the moisture content can be reduced to about 4% to about 13%. In some cases, the moisture content can be deliberately reduced to prepare an MgO core with a moisture content between about 6% and about 8%.

[0084] After the drying process (step 1300) is completed, the MgO product can be subjected to the application of one or more outer layers 1400, as Figure 1 , 5As shown in FIGS. 6 and 7. In these aspects, the product from the drying process 1300 can be transferred to the outer layer application process (step 1405). Feed the MgO product into the application process, where the outer layer can be placed on the surface of the MgO product (e.g., the MgO core formed in the previous step) in step 1410, so as to apply the outer layer in step 1420. Depending on the application, these outer layers can include, but are not limited to, laminates, veneers, melamine, phenolic resin paper, melamine-impregnated phenolic resin paper, vinyl resins, digitally printed inks, polyurethane coatings, dyed coatings, and other such materials. In these aspects, melamine can be selected because of its scratch resistance.

[0085] In one aspect, the outer layer can include a decorative MgO surface covering for placement on the MgO core / product 100. In one exemplary aspect, the MgO core / product 100 includes a first surface 102, a second surface 104, and a thickness 110, as Figure 8 shown. The MgO core can be configured to bond with an additional layer (also interchangeably referred to as an "outer layer" or "top layer" in this disclosure without departing from the broader scope of this disclosure). The additional layer added to the MgO core can be one or more outer layers, which can include single or multiple layers of the materials described herein (e.g., laminates, veneers, etc.). The multiple layers can include, but are not limited to, a decorative layer and a wear-resistant layer. In some instances, the decorative and wear-resistant layers can be a single layer, in which case the top layer can be a single layer. For example, decorative paper impregnated with melamine. In some instances, a single layer of decorative paper impregnated with melamine. In other instances, a primer coating can be applied to the surface of the MgO core and an image can be digitally printed thereon. The image may contain UV ink or other similar types of ink. Although the additional layer can be added to both sides of the MgO core, in some cases, the additional layer is added only to one side of the MgO core. In some aspects, the outer layer can be applied to the first surface 102 of the product 100, the second surface 104 of the product 100, or both. The outer layer can be applied (step 1420) by various methods, including but not limited to hot pressing, cold pressing, double-belt pressing, single daylight pressing, etc.

[0086] The fibers added to the raw materials can also be used to facilitate the application of one or more outer layers to the product 100. In these aspects, short and thin fibers can initially retain water, while long and thin fibers that retain less water are beneficial for the easy application of one or more outer layers 1400. In this regard, the fibers (which were present during the curing process 1200 with high temperature and pressure and subsequent drying) facilitate the application 1400 by absorbing the liquid leaving the outer layer when the outer layer binds to the product. In this regard, the absorption of the liquid into the fibers enables the outer layer to better adhere to the MgO-based product 100 during the application process 1400. In this regard, the application 1400 can be carried out using various methods. Such processes can be carried out at about 260°F up to about 360°F and about 1 Mpa up to about 4 MPa for about 30 seconds up to about 4 hours, depending on the selected application process 1400.

[0087] As described above, the continuous method according to aspects of the present disclosure can significantly reduce the preparation time of MgO products. Traditional wet batch methods can require 6 hours up to 24 hours for curing and 6 hours up to 24 hours for drying, where the intermediate stage between curing and drying can require 12 hours up to several days. Thus, traditional wet batch methods can require 36 hours up to 120 hours to prepare the MgO product 100. Traditional dry batch methods can require 12 hours to 72 hours for curing and 1 hour to 12 hours for drying, where the intermediate stage between curing and drying can require several days. Thus, traditional dry batch methods can require 85 hours up to 156 hours. The continuous method described herein can require about 3 minutes up to about 10 minutes for curing, or other curing times as discussed herein, and about 3 minutes up to about 24 hours for drying. In other examples, drying can require about 1 hour up to about 12 hours. Thus, the continuous method can require about 1 hour 3 minutes up to about 24 hours 10 minutes to produce the MgO product 100, or about 1 hour to about 25 hours. In certain aspects, drying can require about 6 hours to be carried out.

[0088] IV. Compositions and Example Methods

[0089] The following compositions and example methods should be understood as potential compositions and methods related to the present disclosure. Such compositions and example methods are not intended to limit the scope of the present disclosure.

[0090] Table 1 below provides potential compositions for preparing the raw materials. Example 1 provides a high-strength board with a low moisture content after curing, which enables a very rapid drying process. Example 1 may contain unreacted MgO after curing, which may cause the final product 100 to expand in a humid environment. Example 2 contains more water than Example 1, which helps to reduce the level of unreacted MgO. This can help to reduce the undesired expansion of the final product 100. However, a water-to-MgO ratio greater than 1 produces more magnesium hydroxide than the desired crystals (which do not provide strength values). In addition, a water-to-MgO ratio higher than 1 produces air bubbles and may cause problems during the continuous pressing process. Example 3 shows a raw material with too low a fiber content. This low fiber content may result in a low-strength board. In addition, as described herein, the raw materials of the present disclosure should be dry after preparation. Using a low fiber content may result in less water absorption, which is necessary for preparing a dry powder raw material. Example 4 shows a raw material composition containing too much MgCl2. An increase in the salt level attracts indoor moisture and causes condensation to accumulate on the surface of the product 100. This effect is called "sweating".

[0091] Table 1 Example Raw Material Compositions

[0092] Example 1 Example 2 Example 3 Example 4 Component wt% wt% wt% wt% MgO 45 30 42 30 <![CDATA[MgCl2]]> 4 4 4 10 Water 11 35 42 30 Wood fiber 35 31 12 30 Perlite 5 - - -

[0093] In one aspect, the composition of the raw materials can be selected to obtain the desired final product 100. In this regard, the raw materials can be prepared with MgO powder. The MgO-based powder can account for about 30 wt% to about 50 wt% of the raw materials. The fibers can account for about 20 wt% to about 50 wt% of the raw materials. The water can account for about 20 wt% to about 50 wt% of the raw materials. As previously mentioned, all the water in the raw materials is absorbed by the fiber component, such that the raw materials do not suspend in water like a slurry. Instead, the raw materials resemble dry raw material powder with individual fiber components that can be spread on a surface. In certain aspects, the salt accounts for about 3 wt% to about 6% of the raw materials. In this regard, the raw materials can also contain additives. The additives can account for about 0 wt% to about 10 wt% of the raw materials.

[0094] In one aspect, the raw material components can be mixed in a certain order. To facilitate the proper distribution of the materials required to form the MgO core, water and salt can be mixed first, and then the fiber component can be added to absorb the water and salt solution. Then the MgO-based powder can be added. After preparation, the raw materials can be allowed to stand for about 20 - 40 minutes (e.g., 30 minutes) under warm (e.g., about 130 °C up to about 160 °C, such as about 140 °C) and moist (e.g., about 63% up to about 80% humidity, such as about 70% humidity) conditions. This standing allows the cement formation to start before the raw materials are spread. The standing also reduces air pockets due to the reaction of water and MgO starting to occur. After standing for a period of time, any necessary additives can then be added. This raw material preparation sequence is exemplary and non-limiting.

[0095] As described above, an accelerated curing process can result in an excess of salt remaining in the final product. For example, MgCl2 can be used as the salt. When this salt dissolves in water, it decomposes into Mg + ions and Cl2 - ions. Cl2 - will corrode metals. If the amount of salt added to the raw materials is not calculated correctly or the salt does not react completely with MgO, Cl2 ions can remain in the board. These Cl2 - ions are unstable and will attract the H2O contained in the air. The H2O in the air will condense on the board surface and form water droplets, in which a high level of Cl2 - may dissolve in the water droplets. If these droplets come into contact with metals (such as power sockets, metal structures, electrical switches, etc.), Cl2 - will start to corrode all metals, which may cause these systems to malfunction. Therefore, the free chloride ion concentration in the final product 100 can be tested. In one example aspect, the ASTM D512 - 12 test method can be used to test for free chloride. In this regard, the product 100 of the present disclosure contains less than about 6% free chloride ion concentration, thus providing a minimum corrosion risk. In one aspect, the density range of the final product 100 can be from about 1300 kg / m 3 up to about 1700 kg / m 3 . In some aspects, the density range of the final product 100 can be from about 1400 kg / m 3 up to about 1500 kg / m 3 . An increase in the density of the product 100 can improve the strength of the product 100, including but not limited to tensile strength and flexural strength. The density of the product 100 can be affected by various factors. These factors can include but are not limited to air gaps in the product 100, the amount of filler used in the product 100, etc. The density can also affect the tensile strength of the product 100. In some instances, a product 100 with less than 1% of the final product volume consisting of air gaps may be desirable.

[0096] In one aspect, the process steps of the continuous method 1000 can be arranged to occur in a variety of sequences. In this regard, exemplary process steps include, but are not limited to, preparing the raw materials (step 1100), curing (step 1200), drying (step 1300), and applying one or more outer layers (step 1400). In one aspect, the raw materials can be prepared as follows and as Figure 2 shown. First, a salt (see examples of salts above) can be mixed with water to prepare a solution. The solution of salt and water can be added to a blend of desired fibers. In this regard, the desired fibers can be selected from, but are not limited to, wood fibers, bamboo fibers, cellulose fibers, hemp fibers, natural fibers, pecan fibers, natural fibers, synthetic fibers, and other such fibers known in the art. In this regard, the desired fibers can include different lengths and thicknesses. The blend of desired fibers can absorb the solution of salt and water. The blend of desired fibers that has absorbed the salt and water solution may still be dry enough to be spread or dispersed. These fibers are then mixed with MgO, and subsequently any desired additives (such as latex, phosphoric acid, synthetic fibers, perlite, etc.) can be added to ultimately form the raw materials. As described above, the preparation of the raw materials can occur in a number of alternative steps. As described above, curing can begin after the components are mixed because MgO and the salt come into contact in the presence of water.

[0097] The mixture is then spread onto the surface of a moving belt so that an accelerated curing process 1200 can be carried out by a machine, as Figure 3 shown. The curing process 1200 applies high temperature and high pressure to the mixture / raw materials for a given period of time, thereby accelerating the curing. After the accelerated curing process is completed, the product 100 exits the machine and is subsequently transferred to the drying process 1300, as Figure 4 shown, to achieve the desired moisture content. After the target moisture content is reached, the dried product 100 can then have one or more outer layers 1400 applied to have outer layers added on one or both surfaces (see Figure 5 ).

[0098] In one aspect, two or more raw materials having different fiber compositions can be prepared for forming the final product. For example, a first raw material containing short fibers of a selected thickness and material and a second raw material 20 containing long fibers of a selected thickness and material can be prepared. The first raw material can then be laid on the second raw material to obtain the desired product 100 characteristics. As a non-limiting example, the first raw material can be laid on the surface 10 to form a first layer 120, and the second raw material can be laid on the first layer 120 to form a second layer 130, as Figure 9As shown. An additional layer 140 made of different raw materials with different compositions or made using the same raw materials as above can be added to the first layer 120 and the second layer 130. The raw materials containing short fibers can facilitate the application of the outer layer in subsequent process step 1400 and can serve as the outer layer 120 / 140 of the product. In one aspect, other lamination techniques can be used. In this regard, two layers, three layers, four layers, five layers or more layers can be used.

[0099] In one aspect, as described above, the curing process 1200 and the outer layer application process 1400 can be combined. In this regard, before the product enters the machine for the curing process 1200, the outer layer is placed on the surfaces 102 and 104 of the product 100. In this regard, the first outer layer can be placed on the surface. Then the raw materials can be spread on the outer layer. In this regard, then the second outer layer can be placed on the dispersed raw materials. In this regard, the outer layer can include melamine (e.g., a melamine-based layer, such as but not limited to melamine-impregnated paper). In this regard, the outer layer can further include phenolic resin paper. In this regard, the outer layer can further include additives, including but not limited to formaldehyde. In one aspect, the outer layer can also be selected from other materials, including but not limited to veneer, laminate, vinyl resin, digitally printed ink, polyurethane coating, dyed coating, and other such materials. In these aspects, the product 100, now including one or more outer layers adjacent to the surfaces 102 and 104, can be moved along a moving belt into a machine for curing. The product 100 can also be configured to have one or more outer layers adjacent to only one of the surfaces 102 or 104 before being moved along the moving belt into a machine for curing. In this regard, the product 100 can be cured while the outer layer is being joined to the product 100. In this regard, a separate curing process 1200 and outer layer application process 1400 are no longer required. In this regard, production costs and time can be reduced.

[0100] As described above, MgO-based products have some advantages compared to other building materials. As a non-limiting example, incorporating MgO into or on a subfloor (e.g., as a surface covering over a concrete subfloor) can help prevent the subfloor structure from rotting in the case of water penetrating the floor structure. Other materials that can be used in a similar manner (such as high-density fiberboard (HDF), plywood, and oriented strand board (OSB)) do not have such properties and are thus easily damaged by water. MgO-based products also have excellent fire resistance compared to materials such as plywood and OSB boards.

[0101] Although several aspects have been disclosed in the foregoing specification, those skilled in the art will understand that, based on the foregoing description and the teachings presented in the related drawings, numerous modifications and other aspects related to the present disclosure can be contemplated. Accordingly, it is to be understood that the present disclosure is not limited to the specific aspects disclosed above, and that numerous modifications and other aspects are intended to be included within the scope of any claims that can state the disclosed subject matter.

[0102] It should be emphasized that the above aspects are merely possible examples of embodiments, and their elaboration is only for clearly understanding the principles of the present disclosure. Any process description or block diagram in the flowcharts should be understood to represent a part of a module, segment, or code that includes one or more executable instructions for implementing specific logical functions or steps in the process, and includes alternative embodiments, where some functions may be omitted or not executed at all, and executed in an order different from the shown or discussed order, including substantially synchronous or reverse order execution, depending on the functions involved, as understood by those skilled in the art of the present disclosure. Various changes and modifications can be made to the above aspects without materially departing from the spirit and principles of the present disclosure. In addition, the scope of the present disclosure is intended to cover any and all combinations and sub - combinations of all elements, features, and aspects discussed above. All such modifications and changes are intended to be included within the scope of the present disclosure, and all possible claims for each aspect or combination of elements or steps are intended to be supported by the present disclosure.

[0103] Composition

[0104] The above - described method can produce a variety of MgO - based products. In one aspect, the MgO product has a tensile strength of 80 lbf. In another aspect, when immersed in water for 24 hours, the MgO product has a thickness expansion of 3.5%. In one aspect, the MgO product has less than 1% by volume of entrapped air. In one aspect, the thickness of the MgO product is from 3 mm to 15 mm. In another aspect, the thickness of the MgO product is from 5 mm to 9 mm. In one aspect, after curing has been carried out, the moisture content of the MgO product is from 4 to 15% by weight. In one aspect, the MgO product can have an outer layer. For example, the outer layer can include, but is not limited to, laminates, veneers, melamine, resin paper, vinyl, and / or digitally printed inks.

[0105] In one aspect, the MgO product contains a magnesium-based binder, a magnesium-based salt, water, and fibers that form a cement board. The magnesium-based binder may include magnesium oxide (MgO). The MgO ranges from 20 wt% to 50 wt% of the MgO product (by product or raw material). In one aspect, the MgO is in the form of a fine powder. In this case, the powder form ranges between 50 and 150 microns. In one aspect, the MgO product includes less than 5% unreacted MgO. In one aspect, the MgO product has a tensile strength of 80 lbf. In one aspect, when the MgO product is immersed in water for 24 hours, the thickness swells by 3.5%.

[0106] The amount of salt and water (combined as brine) used to ultimately form the MgO product depends on the amount of MgO, the final properties of the product, and the type of salt used to form the brine. However, the weight ratio between MgO and brine should be 0.45 to 1.45 brine / MgO compared to the rest of the raw material mixture. If the water and salt are separated, the ratio of water to MgO should be between 0.3 and 1. The brine ratio depends on the curing temperature and the desired board flexibility and tensile strength, as well as the salt used. In one aspect, the combination of MgO and brine can result in a cement yield of 80%.

[0107] For example, the salt in the MgO product may include magnesium chloride (MgCl2) and / or magnesium sulfate (MgSO4). If it is desired to reduce the swelling of the final product, MgSO4 can be used alone (100% MgSO4 results in a water swelling rate of approximately 0.9%). In this case, the ratio of MgSO4 salt to MgO can be approximately 0.1 to 0.5, or the ratio of MgSO4 brine to MgO is 0.4 to 0.8. If only MgCl2 is used, the ratio of MgCl2 salt to MgO can be between 0.1 and 0.5. However, if the MgO product has good thermal and tensile stability, a mixture of MgCl2 and MgSO4 brine should be used, where the ratio of MgSO4:MgCl2 is desirably 1.5 to 3.0.

[0108] In another aspect, various fibers can be used in the MgO product. The fibers can increase the flexibility and rigidity of the final MgO product while reducing swelling. The fibers can include wood fibers, bamboo fibers, cellulose fibers, hemp fibers, natural fibers, pecan fibers, synthetic fibers, or any combination thereof. In one aspect, the fibers can account for 30 - 40 wt% of the MgO product.

[0109] In one aspect, thinner MgO products can be made with fibers while maintaining the flexibility and tensile strength of the MgO products. In such cases, it is more desirable to use thin and long fibers as described above. For example, a 5 mm thick sample with 30% fiber fill has a tensile strength of 80 lbf. Similarly, a 6 mm thick sample has a tensile strength of 110 lbf, while a 7 mm thick sample has a tensile strength of 120 lbf with 30% fiber fill. These values indicate good flexibility and tensile strength. Thinner MgO products are desired as they can reduce the total weight of the MgO products while maintaining flexibility and tensile strength.

[0110] Microfibrillated fibers or fibers containing small amounts of lignin or unwanted sugars can be used to obtain thin fibers. In these aspects, the fibers can range from 20 to 50 μm. In one aspect, long fibers can be used in the MgO products to increase fiber entanglement and thus improve strength. In one aspect, the length of the fibers can be from 1 to 4 mm. In some aspects, MgO products with long fibers can be sandwiched between layers of MgO products using shorter fibers to prevent telegraphing through surface finishes. The combination of long and thin fibers can increase flexibility, increase rigidity, and improve anti-swelling properties. Short and thin fibers can be used to reduce the number of voids in the final MgO products.

[0111] Example

[0112] Example 1. Characteristics of Plates Prepared Using Traditional Batch Curing Method

[0113] Samples of magnesium oxide-based products were manufactured using a traditional batch curing method. Different sample products were made using a variety of fibers. Then, different samples with different fibers were tested to determine the performance characteristics of the products. Table 2 below lists the six fibers used in each sample.

[0114] Table 2.

[0115]

[0116] The raw material components were mixed in a bench-top mixer according to the formulations described herein. Then, the raw materials were placed on a plate-and-frame press. Then, the surface of the mixture was leveled, and then pressure and heat were applied. The mixture was pressed on the press for about 24 hours, then sanded and dried. Then it was maintained at about 100 °C for about 48 hours. All samples were made with the same water / salt water / cement ratio and filler loading. Then, the samples were tested for flexural strength using ASTM 1037 standard to determine the flexural strength of the resulting products. The thickness of each product sample was about 7 mm. The strength results are provided in Table 3 below.

[0117] Table 3

[0118]

[0119] Table 3 shows samples prepared using ground wood pulp with a traditional batch curing method, yielding the desired 2-day three-point bend (lbf) test results. The ground wood pulp includes microfibrillated lignocellulose fibers not bound to lignin.

[0120] Example 2

[0121] Using the same formulation but changing the fiber source used, seven different fiber sources were tested in product samples. When the product thickness was reduced from approximately 7 mm to approximately 5 mm, each different fiber source substituted into the formulation showed a reduction in tensile strength of approximately 50%. The results are shown in the table below.

[0122] Table

[0123]

[0124] The results show that reducing the fiber thickness from approximately 7 mm to approximately 5 mm reduces the tensile strength by approximately 50%. However, for fibers of the same thickness, using long and thin fibers increases the tensile strength by at least 1.5 times. Any coating on the fibers reduces the strength. Compared to other coatings such as clay coatings, using a resin coating reduces the strength to a greater extent. The presence of lignin in fibers containing lignin (e.g., pine) (such as lignin-bound fibers like pine) reduces the tensile strength.

[0125] The results also show that microfibrillated or long and thin fibers have better tensile strength than short and wide fibers. Compared to control fibers, urea-formaldehyde resin fibers showed a decrease in strength. The resin causes the fibers to bond to each other. The resin also affects the ability of the fibers to absorb water and bond within the cement matrix. Fibers with lengths from approximately 1 mm to approximately 4 mm showed desirable results. Fibers with widths from approximately 20 μm to approximately 50 μm also showed desirable results.

[0126] Example 3

[0127] The product samples were cold-pressed and hot-pressed. The fibers used in the product were microfibrillated fibers. The examples are shown in Table 5 below.

[0128] Table 5

[0129]

[0130] Table 5 (continued)

[0131]

[0132] The results show that when hot pressing is changed to cold pressing, the tensile strength decreases. On the one hand, at 120°F, 80 - 90% of the cement crystals are formed as observed by X-ray diffraction.

[0133] Example 4

[0134] Samples of the products of the present disclosure and competing products were heat treated. All sample products according to the present disclosure contain microfibrillated fibers. It should be noted that ordinary discontinuous wet processes may use a brine:MgO ratio of 1.43:1 or a water:MgO ratio of 0.95:1, where the brine contains water and salt. The continuous hot pressing method of the present disclosure used herein employs a formulation where the brine:MgO ratio ranges from about 0.58:1 to about 0.88:1, or the water:MgO ratio ranges from about 0.45:1 up to about 0.66:1. The results are shown in Table 6 below.

[0135] All dry components of the product formulation are mixed before being added to the liquid components. The powder is added to a mixer rotating at about 140 RPM up to about 290 RPM. The powder is added slowly but continuously through a side port to the rotating mixer. This achieves uniform wetting of the powder and the fibers.

[0136] Table 6

[0137]

[0138] Table 6 (continued)

[0139]

[0140] Table 6 (continued)

[0141]

[0142] The results show the effects of water and temperature on the tensile strength and water stability (e.g., anti-swelling in the presence of water) of the final product. Desirable water stability includes less than 3.5% swelling.

[0143] The results show that according to the first and last rows of Table 5, at 220°F, less water is required. At 220°F, increasing the water decreases the tensile strength of the product.

[0144] Products can also be made using only MgSO4 salt, but their tensile strength is lower than that of products mixed with MgCl2 or using only MgCl2. However, 100% MgSO4 plates have better swelling characteristics / dimensional stability.

[0145] Table 6 shows that the pressing process at 180°F can produce a more stable board compared to 220°F, which has various desired properties, including expansion, density, and flexural strength when using a high water composition. The acceptable expansion range is below 3.5%, and the acceptable flexural strength is above 80 lbf. This indicates that the expansion property is not affected by the flexural strength.

[0146] Table 6 examples illustrate working examples of the raw material components. As a non-limiting example, the salts and water are adjusted in relation to the amount of magnesium oxide. A brine / MgO ratio of 0.45:1 to 1.45:1 is used. A water:MgO ratio of 0.3:1 to 1:1 is used. A MgCl2 salt:MgO ratio of approximately 0.1:1 to approximately 0.5:1 is used. A MgSO4 salt:MgO ratio of approximately 0.1:1 to approximately 0.5:1 is used. A MgSO4 brine:MgO ratio of approximately 0.4:1 to approximately 0.8:1 is used. A MgSO4 brine:MgCl2 brine ratio of approximately 1.5:1 to approximately 3.0:1 is used and shown to be advantageous.

[0147] In addition, the lower water composition prevents the sample product from forming bubbles that may be caused by evaporation during hot pressing. Therefore, raw materials with a lower water composition can be used in methods involving high-temperature pressing processes. During this continuous hot pressing process, a water:MgO ratio of approximately 0.7 can be used. It has been shown that it is advantageous to pre-mix the MgO powder with the fibers when reducing the brine (or water):MgO ratio in the product formulation.

[0148] The above Table 6 shows the effect of the mixture of MgCl2 brine and MgSO4 brine on the tensile strength of the product. The three-point bending result for 100% MgCl2 brine is 115 lbf. The three-point bending result for 100% MgSO4 brine is 84 lbf.

[0149] The results show that the pressing temperature also affects the product strength. Higher temperatures require more water to be removed from the raw material mixture before pressing. A water:MgO ratio as low as approximately 0.40:1 can be used. A water:MgO ratio of approximately 0.66:1 can be used at approximately 82°C. Due to the appearance of steam voids at approximately 104°C, the final strength is affected. Due to the reduced amount of water, a water:MgO ratio of approximately 0.45:1 is applicable to approximately 104°C. A water:MgO ratio of approximately 0.3:1 has been shown to be applicable.

[0150] The results show that MgSO4 and lower temperatures have a great impact on water stability. Compared to MgCl2 crystals, MgSO4 provides a more stable crystal structure, which forms better at higher temperatures. The percentage of water expansion for a formulation using 100% MgSO4 as the salt is approximately 0.9%. The percentage of water expansion for a formulation using 100% MgCl2 as the salt is approximately 3.4%.

[0151] Example 5

[0152] In one aspect, a sample product made with Fiber 4 in Table 2 produced desirable 2-day three-point bend (lbf) test results. The fiber is a fine, fluffy powder that appears fibrillated when viewed under a scanning electron microscope (SEM). Additional three-point bend tests on products using this fiber also produced desirable properties. The tests consistently produced results above 130 lbf at a 30% weight loading. An image of Fiber 4 before it was incorporated into the sample product is shown in Figures 10-12 . An example of the sample product using Fiber 4 is shown in Figure 13 .

Claims

1. A method for preparing a magnesium oxide (MgO)-based product, the method comprising: a. preparing at least one raw material, wherein the at least one raw material comprises magnesium oxide; b. transferring the at least one raw material to a curing process, wherein the curing process is continuous and carried out under high temperature and high pressure; and c. moving the product of the curing process to a drying process.

2. The method according to claim 1, wherein the at least one raw material further comprises salt.

3. The method according to claim 1, wherein the at least one raw material further comprises water.

4. The method according to claim 1, wherein the at least one raw material further comprises fiber.

5. The method according to claim 4, wherein the fiber further comprises fibers of different lengths and thicknesses, including wood fiber, bamboo fiber, cellulose fiber, hemp fiber, natural fiber, pecan fiber, synthetic fiber, or any combination thereof.

6. The method according to claim 1, wherein the at least one raw material further comprises an additive.

7. The method according to claim 1, wherein more than one raw material is prepared, and wherein the more than one raw material comprises fibers of different lengths.

8. The method according to claim 1, wherein the curing process occurs at about 155°F up to about 310°F.

9. The method according to claim 1, wherein the curing process occurs at about 3 MPa up to about 13 MPa.

10. The method according to claim 1, wherein the curing process uses a double-belt press.

11. The method according to claim 1, wherein the curing process produces an MgO-based product with a moisture content of about 4% up to about 20% within about 3 minutes up to about 60 minutes.

12. The method according to claim 1, wherein the drying process produces an MgO-based product with a moisture content of about 4% up to about 13%.

13. The method according to claim 1, wherein the MgO-based product is about 3 mm up to about 15 mm.

14. The method according to claim 1, which further comprises an outer layer application process.

15. The method according to claim 14, wherein the outer layer application process comprises applying one or more outer layers to one or more sides of the MgO-based product after the drying process.

16. The method according to claim 15, wherein the outer layer is selected from laminates, veneers, melamine, phenolic resin paper, melamine-impregnated phenolic resin paper, vinyl resin, digitally printed inks, polyurethane coatings, dyed coatings, and other such materials.

17. The method according to claim 14, wherein the outer layer application process and the curing process are carried out simultaneously.

18. The method according to claim 17, wherein the outer layer application process comprises applying one or more outer layers to one or more sides of the MgO-based product before the curing process.

19. The method according to claim 18, wherein when the MgO-based product moves through the continuous curing process, the one or more outer layers are bonded to the product.

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