Building panel

Abstract

Disclosed is a formaldehyde free gypsum product comprising gypsum, a moisture-resistant additive, a dispersant, and a liner. Suitable moisture-resistant additives include those selected from the group consisting of waxes, water-resistant polymers, and monomers or oligomers that polymerize in-situ. The moisture-resistant additive can be a stearate, for example, a metallic stearate.

Description

BUILDING PANELCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application Nos. 63 / 560,053, filed March 1, 2024, and 63 / 636,902, filed April 22, 2024, each of which is herein incorporated by reference in its entirety for all purposes.BACKGROUND OF THE INVENTION

[0002] Formaldehyde is a volatile organic compound that can be released from building materials, including gypsum board, into the air. Therefore, it is important to develop and use gypsum board products that are free of formaldehyde to minimize the potential health risks and improve indoor air quality.BRIEF SUMMARY OF THE INVENTION

[0003] Disclosed are gypsum products containing zero formaldehyde in the finished good state. Embodiments can include gypsum boards, for example, weatherable gypsum boards and water-resistant gypsum boards.

[0004] An embodiment of the invention is a formaldehyde free gypsum product comprising: a) gypsum; b) a moisture-resistant additive; c) a dispersant; and d) a liner.

[0005] In an embodiment, the moisture-resistant additive is selected from the group consisting of waxes, water-resistant polymers, and monomers or oligomers that polymerize in-situ.

[0006] In an embodiment, the moisture-resistant additive is a stearate.

[0007] In an embodiment, at least one stearate comprises a metallic stearate.

[0008] In an embodiment, the formaldehyde free gypsum product further comprises at least one wax.

[0009] In an embodiment, the wax comprises at least one of linear, cross-liked, branched and charged waxes.

[0010] In an embodiment, the moisture-resistant additive comprises one or more compounds that polymerize after contact with gypsum stucco slurry.

[0011] In an embodiment, the moisture-resistant additive is selected from the group consisting of linear waxes, cross-linked waxes, branched waxes, charged waxes, water- resistant polymers, polymers that can polymerize in-situ, and stearates.

[0012] In an embodiment, the dispersant is selected from the group consisting of polycarboxylate ethers, polycarboxylate esters, polystyrene sulfonates, lignin-based dispersants and mixtures of one or more of these.

[0013] In an embodiment, the polystyrene sulfonate comprises sodium polystyrene sulfonate (PSS).

[0014] In an embodiment, the lignin-based dispersant comprises a lignosulfonate.

[0015] In an embodiment, the lignosulfonate is selected from the group consisting of aluminum lignosulfonate, ammonium lignosulfonate, calcium lignosulfonate, copper lignosulfonate, magnesium lignosulfonate, potassium lignosulfonate, sodium lignosulfonate, and zinc lignosulfonate.

[0016] In an embodiment, the dispersant is selected from the group consisting of a polycarboxylate ether, a polycarboxylate ester, polystyrene sulfonates, and lignin-based dispersants.

[0017] In an embodiment, the liner comprises a cellulose-based material.

[0018] In an embodiment, the cellulose-based material further comprises a water-resistant coating.

[0019] In an embodiment, the water-resistant coating further comprises a weatherable coating.

[0020] In an embodiment, the liner comprises at least one of: a) a melt spun non-woven; b) a coated glass fiber mat; c) an uncoated fiber glass mat; d) a polymeric mat with glass fibers; e) a natural fiber nonwoven; f) a nonwoven or woven glass or polymeric scrims; g) a spun bond nonwoven; h) a hydroentangled nonwoven; and i) a nonwoven with aspect ratio layering.SPECIFIC EMBODIMENTS

[0021] 1. A formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from cellulose-based materials with water-resistant and weatherable coatings, and linear waxes as a water-resistant additive.

[0022] 2. A formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from extruded polymer films, and cross-linked waxes as a water-resistant additive.

[0023] 3. A formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from melt-spun non-wovens, and branched waxes as a water-resistant additive.

[0024] 4. A formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from coated glass fiber mats, and charged waxes as a water-resistant additive.

[0025] 5. A formaldehyde-free gypsum board manufactured with a poly carboxylate ether, a liner made from uncoated fiber glass mats, and water-resistant polymers as a water-resistant additive.

[0026] 6. A formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from polymeric mats with glass fibers, and molecules that when added can polymerize in-situ as a water-resistant additive.

[0027] 7. A formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from natural fiber nonwovens, and metallic stearates as a water-resistant additive.

[0028] 8. A formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from nonwoven and woven glass or polymeric scrims, and linear waxes as a water-resistant additive.

[0029] 9. A formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from spun bond nonwovens, and cross-linked waxes as a water-resistant additive.

[0030] 10. A formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from hydroentangled nonwovens, and branched waxes as a water-resistant additive.

[0031] 11. A formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from nonwovens with aspect ratio layering, and charged waxes as a water- resistant additive.

[0032] 12. A formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from other coated nonwovens, and water-resistant polymers as a water-resistant additive.

[0033] 13. A formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from cellulose-based materials with water-resistant and weatherable coatings, and molecules that when added can polymerize in-situ as a water-resistant additive.

[0034] 14. A formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from extruded polymer films, and metallic stearates as a water-resistant additive.

[0035] 15. A formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from melt-spun non-wovens, and linear waxes as a water-resistant additive.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0036] Having thus described the subject matter in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale.

[0037] Figure 1A is an exemplary diagram of a gypsum panel cross section comprising two slate coat layers.

[0038] Figure IB is an exemplary diagram of a gypsum panel cross section comprising one slate coat layer.

[0039] Figure 1C is an exemplary diagram of a gypsum panel cross section lacking a slate coat layer.Example Embodiment #1

[0040] A formaldehyde free gypsum panel includes gypsum core and can have but is not required to have one or two slate coat layers. If they are present the second slate coat layer is present on the face of the gypsum core opposite the first slate coat layer. The slate coat layer(s) and the gypsum core collectively may be referred to as the gypsum layers, as the slate coat layers are also made of gypsum.

[0041] Each “gypsum layer” may be manufactured by adding water to a mixture primarily made up of calcium sulfate hemihydrate (also known as “stucco”). The hydration of the calcium sulfate hemihydrate creates calcium sulfate dihydrate which is also referred to as gypsum. During this hydration reaction and the formation of the gypsum layer additives are utilized to impart additional properties on the gypsum layer. These additives include but are not limited to fiber glass for enhanced strength and fire resistance of the gypsum layer, and a water reducing agent which is also referred to as a dispersant or super plasticizer.

[0042] The gypsum panel also comprises one or two face layers that are associated with the gypsum panel. The second face layer, if present, is present on a face of the gypsum panel opposite the first face layer.DEFINITIONS

[0043] It is understood that where a parameter range is provided, all integers and ranges within that range, and tenths and hundredths thereof, are also provided by the embodiments. For example, “5-10%” includes 5%, 6%, 7%, 8%, 9%, and 10%; 5.0%, 5.1%, 5.2%....9.8%, 9.9%, and 10.0%; and 5.00%, 5.01%, 5.02%....9.98%, 9.99%, and 10.00%, as well as, for example, 6-9%, 8-10%, 5. l%-9.9%, and 5.01%-9.99%. Similarly, where a list is presented, unless stated otherwise, it is to be understood that each individual element of that list, and every combination of components of that list, is a separate embodiment. For example, “1, 2, 3, 4, and 5” encompasses, among numerous embodiments, 1; 2; 3; 1 and 2; 3 and 5; 1, 3, and 5; and 1, 2, 4, and 5. All ranges are inclusive of their endpoints unless otherwise stated.

[0044] As used herein, “about” means within a statistically meaningful range of a value or values such as a stated concentration, length, molecular weight, pH, sequence identity, time frame, temperature or volume. Such a value or range can be within an order of magnitude, typically within 20%, more typically within 10%, and even more typically within 5% of a given value or range. The allowable variation encompassed by “about” will depend upon the particular system under study, and can be readily appreciated by one of skill in the art.

[0045] As used herein, “msf’ refers to 1,000 square feet.

[0046] The term “liner” means a woven or nonwoven sheet affixed to a surface of a gypsum product. If the product is a gypsum board, the liner can be affixed to the front surface, the back surface or both surfaces of the gypsum board. The terms “face layer,” “mat”, “liner” and “scrim” can be used interchangeably when the sheet is affixed to a surface of the gypsum product. “Scrim” can be used to describe a highly permeable mat which can optionally be encased or immersed in a gypsum layer or in a higher density layer comprising gypsum, often referred to as a slate coat.

[0047] The term “zero formaldehyde” as used herein means that the product does not contain formaldehyde and does not release formaldehyde in its normal intended use. For example, the formaldehyde is not present in the raw material components, the raw material processing, finished good processing, product installation, and is not evolved during the product lifetime. The term “zero formaldehyde,” describing a product, does not proscribe peripheral manufacturing steps that are external to the products. For example, formaldehyde can beintroduced to the manufacturing process as a minor component in a fuel gas stream. Similarly, products can be cross-contaminated by other products manufactured in the facility, or by the presence of human beings, who naturally produce and exhale formaldehyde as part of their metabolism.

[0048] The term “raw material components” means the constituents that make up gypsum board manufacturing (i.e. a liner, gypsum, water resistant additive, dispersant, reinforcing fiber, etc.).

[0049] The term “detectable levels of formaldehyde in raw material components” means formaldehyde detectable by currently used formaldehyde measurement methods including SDS and chemical composition analysis tools such as headspace gas chromatography and mass spectroscopy.

[0050] The term “raw material processing” means the steps of preparing the finely divided stucco powder, including mixing, layering, and drying gypsum slurries, including any additives, and preparing and adding glass mats and other non-gyspum layers.

[0051] Measurement methods for determining formaldehyde evolved during raw material processing include the volatile organic compound (VOCs) emission via measurement methods like EPA 323 and corresponding analytical methods, ASTM D7770-12(2019), or UL GREENGUARD Gold.

[0052] The term “product installation and product lifetime” means the period beginning with installation of the gypsum product through demolition. “Product installation and product lifetime” does not include post-consumer recycling. During product installation and product lifetime, “detectable levels of formaldehyde” are those levels of formaldehyde in volatile organic compound (VOCs) emission using measurement methods such as ASTM D7770- 12(2019) and UL GREENGUARD Gold.

[0053] As used herein, the term "slate coat" refers to a gypsum slurry having a higher wet density than the remainder of the gypsum slurry that forms the gypsum core. In some embodiments, the slate coat is formed from a slurry which lacks a foaming agent, but is otherwise identical to the slurry used to form the gypsum core.DETAILED DESCRIPTION

[0054] Gypsum slurry and layers

[0055] As noted above, each gypsum layer may be manufactured by adding water to a mixture primarily made up of calcium sulfate hemihydrate (stucco).

[0056] In embodiments, gypsum slurries are prepared with a stucco to water ratio of 100 parts of stucco to 50-100 parts of water.

[0057] In certain embodiments, the gypsum slurries of the present disclosure, used to form the gypsum core or the slate coat layers, further contain one or more ingredients or additives to achieve the desired board properties. Various additives are discussed herein and may be used in any combination. In particular, suitable additives may include, but are not limited to, one or more of starch, fiberglass, dispersants, ball mill accelerators, retarders, potash, polyphosphates, and polymer binders.

[0058] In certain embodiments, as shown in FIG. 1 A, a gypsum panel 100 includes a gypsum core 102, and two slate coat layers 104, 106. The second slate coat layer 106 is present on a face of the gypsum core 102 opposite the first slate coat layer 104. The two slate coat layers 104, 106 and the gypsum core 102, collectively, may be referred to as the gypsum layers 101, as the slate coat layers 104, 106 are also made of gypsum. The gypsum panel also comprises two liners 108, 110 that are associated with the gypsum panel 101. The second liner 110 is present on a face of the gypsum panel opposite the first liner 108. In some embodiments, one or both of the liners 108, 110 may have a coating disposed on one or both surfaces thereof, prior to combination with the gypsum slurry, or, for external surface coatings, after combination with the gypsum slurry. In an alternate embodiment, there is only one liner (108 or 110).

[0059] Another embodiment, shown in FIG. IB, is identical to that depicted in FIG. 1A, but without a second slate coat layer 106. The gypsum core 102 is directly adjacent to the second liner 110. Thus, the gypsum layers 101 include only the gypsum core 102 and the first slate coat layer 104. In an alternate embodiment, there is only one liner (108 or 110).

[0060] Another embodiment, shown in FIG. 1C, is identical to that depicted in FIG. 1A, but without any slate coat layers. The gypsum core 102 is directly adjacent to both the first liner 108 and the second liner 110. Thus, the only component in the gypsum layers 101 is the gypsum core 102. In an alternate embodiment, there is only one liner (108 or 110).

[0061] During manufacturing, gypsum slurries are be deposited on the uncoated surface of a liner material (which may be pre-coated offline or online), and set to form a gypsum core ofthe panel. The gypsum slurries may adhere to a liner or penetrate some portion of the thickness of the liner, and provide a mechanical bond for the panel. In an embodiment, there are three gypsum slurry layers applied, in order, to form the embodiment depicted in Fig. 1 A: 1) a first slate coat slurry; 2) a gypsum core layer slurry; and 3) a second slate coat slurry. In an embodiment, the first and the second slate coat slurries are identical. In an embodiment, there are two gypsum slurry layers applied, in order, to form the embodiment depicted in Fig. IB: 1) a first slate coat slurry; and 2) a gypsum core layer slurry. Following the deposition of the gypsum slurry layers, a second liner is laid on top of the slurries, prior to curing.

[0062] In embodiments comprising more than one liner, the liners do not need to be identical. For example, in an embodiment where both liners are glass mats, one liner may be uncoated while the other liner is coated. The components in each of the liners are independent of each other.

[0063] A suitable polyphosphate may be contained in a gypsum slurry. For example, the polyphosphate may be sodium trimetaphosphate (STMP), sodium hexametaphosphate (SHMP), ammonium polyphosphate (APP). Other suitable phosphate salts may also be used and include other metaphosphate, polyphosphate, and pyrophosphate salts, such as ammonium trimetaphosphate, potassium trimetaphosphate, lithium trimetaphosphate, calcium trimetaphosphate, sodium calcium trimetaphosphate, aluminum trimetaphosphate; ammonium, lithium, or potassium hexametaphosphates; sodium tripolyphosphate, potassium tripolyphosphate, sodium and potassium tripolyphosphate; calcium pyrophosphate, tetrapotassium pyrophosphate, and / or tetrasodium pyrophosphate.

[0064] In certain embodiments, a polyphosphate is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 1 percent, by weight. In certain embodiments, the polyphosphate is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 0.5 percent, by weight. In some embodiments, the polyphosphate is present in the relevant gypsum layer or slurry in an amount of about 0.05 percent to about 0.2 percent, by weight. In some embodiments, the polyphosphate is present in the relevant gypsum layer or slurry in an amount of about 1 Ib / msf to about 50 Ib / msf, for a gypsum panel having a thickness of about 14 inch to about 1 inch.

[0065] For example, a suitable polymer binder, such as an organic polymer binder may be contained in a gypsum slurry. Suitable polymer binders may include polymeric emulsions and resins, e.g., acrylics, siloxane, silicone, styrene-butadiene copolymers, polyethylene-vinyl acetate, polyvinyl alcohol, polyvinyl chloride (PVC), polyurethane, phenolics resin, polyvinyl butyryl, styrene-acrylic copolymers, styrene-vinyl-acrylic copolymers, styrene-maleicanhydride copolymers. In some embodiments, the binders may include UV curable monomers and polymers (e.g., epoxy acrylate, urethane acrylate, polyester acrylate). For example, on a dry basis, the polymer binder content in the relevant gypsum layer or slurry may be between 1 Ib / msf to 50 Ib / msf, for a gypsum panel having a thickness of about 1 / 4 inch to 1 inch.

[0066] In certain embodiments, a polymer binder is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 1 percent, by weight. In certain embodiments, the polymer binder is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 0.5 percent, by weight. In some embodiments, the polymer binder is present in the relevant gypsum layer or slurry in an amount of about 0.05 percent to about 0.2 percent, by weight. In some embodiments, the polymer binder is present in the relevant gypsum layer or slurry in an amount of about 1 Ib / msf to about 50 Ib / msf, for a gypsum panel having a thickness of about 14 inch to about 1 inch.

[0067] In certain embodiments, each of the slate coat layers is deposited in an amount of from about 5 percent to about 20 percent, by weight, of the gypsum layers. This would mean that the gypsum core layer comprises about 80 to about 95 percent of the total weight of the gypsum layers, when one slate coat layer is present, and about 60 to about 90 percent of the total weight of the gypsum layers, when two slate coat layers are present. The gypsum slurries may be deposited by any suitable means, such as roll coating.

[0068] In certain embodiments, a gypsum layer or slurry contains one or more additional agents to enhance its performance, such as, but not limited to, wetting agents, moisture resistance agents, fillers, accelerators, set retarders, foaming agents, polyphosphates, and dispersing agents. Various example uses of such further additives will now be described.

[0069] In certain embodiments, a wetting agent is selected from a group consisting of surfactants, superplasticisers, dispersants, agents containing surfactants, agents containing superplasticisers, agents containing dispersants, and combinations thereof. For example, suitable superplasticisers include Melflux 2651 F and 4930F, commercially available from BASF Corporation. In certain embodiments, the wetting agent is a surfactant having a boiling point of 200° C. or lower. In some embodiments, the surfactant has a boiling point of 150° C. or lower. In some embodiments, the surfactant has a boiling point of 110° C. or lower. For example, the surfactant may be a multifunctional agent based on acetylenic chemistry or an ethoxylated low-foam agent.

[0070] In certain embodiments, a surfactant is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 1 percent, by weight. In certain embodiments, the surfactant is present in the relevant gypsum layer or slurry in an amount of about 0.01 percentto about 0.5 percent, by weight. In some embodiments, the surfactant is present in the relevant gypsum layer or slurry in an amount of about 0.05 percent to about 0.2 percent, by weight. In some embodiments, the surfactant is present in the relevant gypsum layer or slurry in an amount of about 1 Ib / msf to about 50 Ib / msf, for a gypsum panel having a thickness of about % inch to about 1 inch.

[0071] Suitable surfactants and other wetting agents may be selected from non-ionic, anionic, cationic, or zwitterionic compounds, such as alkyl sulfates, ammonium lauryl sulfate, sodium lauryl sulfate, alkyl-ether sulfates, sodium laureth sulfate, sodium myreth sulfate, docusates, dioctyl sodium sulfosuccinate, perfluorooctanesulfonate, perfluorobutanesulfonate, linear alkylbenzene sulfonates, alkyl-aryl ether phosphates, alkyl ether phosphate, alkyl carboxylates, sodium stearate, sodium lauroyl sarcosinate, carboxylate-based fluorosurfactants, perfluorononanoate, perfluorooctanoate, amines, octenidine dihydrochloride, alkyltrimethylammonium salts, cetyl trimethylammonium bromide, cetyl trimethylammonium chloride, cetylpyridinium chloride, benzalkonium chloride, benzethonium chloride, 5-Bromo- 5 -nitro- 1,3 -di oxane, dimethyldioctadecylammonium chloride, cetrimonium bromide, dioctadecyldimethylammonium bromide, sultaines, cocamidopropyl hydroxysultaine, betaines, cocamidopropyl betaine, phospholipids phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, sphingomyelins, fatty alcohols, cetyl alcohol, stearyl alcohol, cetostearyl alcohol, stearyl alcohols, oleyl alcohol, polyoxyethylene glycol alkyl ethers, octaethylene glycol monododecyl ether, pentaethylene glycol monododecyl ether, polyoxypropylene glycol alkyl ethers, glucoside alkyl ethers, polyoxyethylene glycol octylphenol ethers, polyoxyethylene glycol alkylphenol ethers, glycerol alkyl esters, polyoxyethylene glycol sorbitan alkyl esters, sorbitan alkyl esters, cocamide MEA, cocamide DEA, dodecyldimethylamine oxide, polyethoxylated tallow amine, and block copolymers of polyethylene glycol and polypropylene glycol. For example, suitable surfactants include Surfynol 61, commercially available from Air Products and Chemicals, Inc. (Allentown, PA).

[0072] In certain embodiments, a moisture resistance or hydrophobizing agent is provided in the gypsum slurry or layers thereof to impart desired moisture resistance and / or processing properties to the panel. For example, the moisture resistance or hydrophobizing agent may include a wax, wax emulsions or co-emulsions, silicone, siloxane, siliconate, or any combination thereof. In certain embodiments, a moisture resistance or hydrophobizing agent is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 1 percent, by weight. In certain embodiments, the moisture resistance or hydrophobizing agent is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about0.5 percent, by weight. In some embodiments, the moisture resistance or hydrophobizing agent is present in the relevant gypsum layer or slurry in an amount of about 0.05 percent to about 0.2 percent, by weight. In some embodiments, the moisture resistance or hydrophobizing agent is present in the relevant gypsum layer or slurry in an amount of about 1 Ib / msf to about 50 Ib / msf, for a gypsum panel having a thickness of about % inch to about 1 inch.

[0073] In certain embodiments, the gypsum slurry (or one or more layers thereof) is substantially free of foam, honeycomb, excess water, and micelle formations. As used herein, the term “substantially free” refers to the slurry containing lower than an amount of these materials that would materially affect the performance of the panel. That is, these materials are not present in the slurry in an amount that would result in the formation of pathways for liquid water in the glass mat of a set panel, when under pressure.

[0074] In certain embodiments, a gypsum slurry layer, and particularly a slate coat layer, may be deposited on a horizontally oriented moving web of facer material, such as pre-coated fibrous mat or paper facing material. A second coated or uncoated web of facer material may be deposited onto the surface of the gypsum slurries (particularly a second slate coat slurry) opposite the first web of facer material, e.g., a non-coated surface of the second web of facer material contacts the gypsum slurry layer. In some embodiments, a moving web of a facer material may be placed on the upper free surface of the gypsum slurry. Thus, the gypsum layers may be sandwiched between two facer materials, none, one or both having a coating. In certain embodiments, allowing the gypsum layer slurries and / or coating to set includes curing, drying, such as in an oven or by another suitable drying mechanism, or allowing the material(s) to set at room temperature (i.e., to self-harden).

[0075] A barrier coating may be applied to both face layers, prior to or after drying of the face layers. In some embodiments, the glass mats are pre-coated when they are associated with the slate coat slurry. In some embodiments, depositing a barrier coating onto the second surface of the first coated face layer occurs after setting the first gypsum slurry to form a slate core layer. In some embodiments, the slate coat layer coated with the barrier coating is cured, dried, such as in an oven or by another suitable drying mechanism, or the materials are allowed to set at room temperature. In some embodiment, infrared heating is used to flash off water and dry the barrier coating.

[0076] Suitable coating materials (i.e., the precursor to the dried mat coating) may contain at least one suitable polymer binder. Suitable polymer binders may be selected from polymeric emulsions and resins, e.g. acrylics, siloxane, silicone, styrene-butadiene copolymers, polyethylene-vinyl acetate, polyvinyl alcohol, polyvinyl chloride (PVC), polyurethane,phenolics resin, polyvinyl butyryl, styrene-acrylic copolymers, styrene-vinyl-acrylic copolymers, styrene-maleic anhydride copolymers. In some embodiments, the polymer binder is an acrylic latex or a polystyrene latex. In some embodiments, the polymer binder is hydrophobic. In certain embodiments, the binder includes UV curable monomers and / or polymers (e.g. epoxy acrylate, urethane acrylate, polyester acrylate). In certain embodiments, the mat coating contains the polymer binder in an amount of from about 5 percent to about 75 percent, by weight, on a dry basis.

[0077] Examples of suitable polymer binders that may be used in the continuous barrier coatings described herein include SNAP 720, commercially available from Arkema Coating Resins, which is a structured nano-particle acrylic polymer containing 100% acrylic latex and 49% solids by weight, with a 0.08 micron particle size; SNAP 728, commercially available from Arkema Coating Resins, which is a structured nano-acrylic polymer containing 100% acrylic latex and 49% solids by weight, with a 0.1 micron particle size; and NEOCAR 820, commercially available from Arkema Coating Resins, which is a hydrophobic modified acrylic latex containing 45% solids by weight, with a 0.07 micron particle size.

[0078] In certain embodiments, the mat coating also contains one or more inorganic fillers. For example, the inorganic filler may be calcium carbonate or another suitable filler known in the industry. In certain embodiments, the filler is an inorganic mineral filler, such as ground limestone (calcium carbonate), clay, mica, gypsum (calcium sulfate dihydrate), aluminum trihydrate (ATH), antimony oxide, sodium-potassium alumina silicates, pyrophyllite, microcrystalline silica, and talc (magnesium silicate). In certain embodiments, the filler may inherently contain a naturally occurring inorganic adhesive binder. For example, the filler may be limestone containing quicklime (CaO), clay containing calcium silicate, sand containing calcium silicate, aluminum trihydrate containing aluminum hydroxide, cementitious fly ash, or magnesium oxide containing either the sulfate or chloride of magnesium, or both. In certain embodiments, the filler may include an inorganic adhesive binder as a constituent, cure by hydration, and act as a flame suppressant. For example, the filler may be aluminum trihydrate (ATH), calcium sulfate (gypsum), and the oxychloride and oxysulfate of magnesium. For example, fillers may include MINEX 7, commercially available from the Cary Company (Addison, IL); IMSIL A- 10, commercially available from the Cary Company; and TALCRON MP 44-26, commercially available from Specialty Minerals Inc. (Dillon, MT). The filler may be in a particulate form. For example, the filler may have a particle size such that at least 95% of the particles pass through a 100 mesh wire screen.

[0079] In certain embodiments, the precursor material that forms the mat coating also contains water. For example, the coating material may contain the polymer binder in an amount of from about 35 percent to about 80 percent, by weight, and water in an amount of from about 20 percent to about 30 percent, by weight. In embodiments containing the filler, the continuous barrier coating material may also contain an inorganic filler in an amount of from about 35 percent to about 80 percent, by weight. In some embodiments, the polymer binder and the inorganic filler are present in amounts of within 5 percent, by weight, of each other. For example, the polymer binder and filler may be present in a ratio of approximately 1 : 1.

[0080] In some embodiments, the mat coating also includes water and / or other optional ingredients such as colorants (e.g., dyes or pigments), transfer agents, thickeners or rheological control agents, surfactants, ammonia compositions, defoamers, dispersants, biocides, UV absorbers, and preservatives. Thickeners may include hydroxyethyl cellulose; hydrophobically modified ethylene oxide urethane; processed attapulgite, a hydrated magnesium aluminosilicate; and other thickeners known to those of ordinary skill in the art. For example, thickeners may include CELLOSIZE QP-09-L and ACRYSOL RM-2020NPR, commercially available from Dow Chemical Company (Philadelphia, Pa.); and ATTAGEL 50, commercially available from BASF Corporation (Florham Park, N.J.). Surfactants may include sodium polyacrylate dispersants, ethoxylated nonionic compounds, and other surfactants known to those of ordinary skill in the art. For example, surfactants may include HYDROP ALAT 44, commercially available from BASF Corporation; and DYNOL 607, commercially available from Air Products (Allentown, Pa.). Defoamers may include multi-hydrophobe blend defoamers and other defoamers known to those of ordinary skill in the art. For example, defoamers may include FOAMASTER SA-3, commercially available from BASF Corporation. Ammonia compositions may include ammonium hydroxide, for example, AQUA AMMONIA 26 BE, commercially available from Tanner Industries, Inc. (Southampton, Pa.). Biocides may include broad-spectrum microbicides that prohibit bacteria and fungi growth, antimicrobials such as those based on the active diiodomethyl-p-tolylsulfone, and other compounds known to those of ordinary skill in the art. For example, biocides may include KATHON LX 1.5%, commercially available from Dow Chemical Company, POLYPHASE 663, commercially available from Troy Corporation (Newark, N.J.), and AMICAL Flowable, commercially available from Dow Chemical Company. Biocides may also act as preservatives. UV absorbers may include encapsulated hydroxyphenyl-triazine compositions and other compounds known to those of ordinary skill in the art, for example, TINUVIN 477DW, commercially available from BASF Corporation. Transfer agents such as polyvinyl alcohol (PVA) and othercompounds known to those of ordinary skill in the art may also be included in the coating composition.

[0081] While this disclosure is generally directed to gypsum panels, it should be understood that other cementitious panel core materials comprising the first and second additive packages are also intended to fall within the scope of the present disclosure. For example, cementitious panel core materials such as those including magnesium oxide or aluminosilicate may be substituted for the gypsum of the embodiments disclosed herein, to achieve similar results. Similarly, composite panels comprising a cementitious layer, in which the cementitious layer comprises the first and second additive packages, are also within the scope of the present disclosure.LINER

[0082] The disclosed gypsum product can include a liner. Suitable materials for liners are formaldehyde free. Examples of such materials include but are not limited to: cellulose- based materials with water resistant and weatherable coatings, extruded polymer films, melt spun non-wovens, coated glass fiber mats, uncoated fiber glass mats, polymeric mats with glass fibers, natural fiber nonwovens, nonwoven and woven glass or polymeric scrims, spun bond nonwovens, hydroentangled nonwovens, nonwovens with aspect ratio layering, other coated nonwovens as well, and / or any composites of these materials, etc. CELLULOSE-BASED LINERS

[0083] Here are a few cellulose-based options that could be considered for providing good weather and water resistance to gypsum board:

[0084] 1. Asphalt-Coated Cellulose Liners: Asphalt impregnation of the cellulose liners can provide a significant barrier to water. This method involves coating the cellulose fibers with asphalt or bitumen, which is hydrophobic and helps to repel water.

[0085] 2. Silicone-Treated Cellulose Liners: Silicone compounds can be used to treat cellulose liners, giving them hydrophobic properties. Silicone can penetrate the fibers and provide durable water resistance without significantly affecting the breathability of the liner.

[0086] 3. Acrylic or Latex-Modified Cellulose Liners: Acrylic or latex polymers can be added to cellulose liners to improve their moisture resistance. These polymers form a film that can protect the gypsum board from water ingress.

[0087] 4. Wax-Emulsion-Treated Cellulose Liners: Wax emulsions can be used to treat cellulose fibers, providing a water-resistant coating. When the emulsion dries, it leaves behind a layer of wax that helps to repel water.

[0088] 5. Polymer-Enhanced Cellulose Liners: Various polymers, such as polyvinyl acetate (PVA), can be integrated into the cellulose liners to create a barrier to moisture. These polymers can provide added strength and resistance to the liners.

[0089] 6. Glass Fiber Reinforced Cellulose Liners: Although not purely cellulose-based, incorporating glass fibers can increase the structural integrity of the liners and provide better moisture resistance.

[0090] When selecting the appropriate cellulose-based liner, it is important to consider the specific application and exposure conditions the gypsum board will face. The chosen liner should provide a balance between water resistance, durability, and the ability to allow the material to breathe to prevent trapped moisture and potential mold growth.EXTRUDED POLYMER FILMS

[0091] For improving water resistance in gypsum board, extruded polymer films can be applied to create a barrier that reduces moisture absorption. These films can be applied to the surface of the disclosed gypsum board during the manufacturing process, and they must exhibit good adhesion to the gypsum core and any paper or fibrous facers that may optionally be used.

[0092] Factors to consider in selecting an extruded polymer film for the disclosed gypsum products include durability, moisture barrier properties, and compatibility with the board's intended use. Suitable extruded polymer films include the following non-limiting examples.

[0093] 1. Polyethylene (PE): PE films can be used due to their moisture barrier properties and chemical resistance. Low-density polyethylene (LDPE) films can provide a flexible, water-resistant surface.

[0094] 2. Polyvinylidene Chloride (PVDC): PVDC films can provide moisture and vapor barrier properties. They are resistant to water and have good chemical stability.

[0095] 3 Ethylene Vinyl Alcohol (EVOH): EVOH films provide barrier properties against gases and moisture.

[0096] 4. Polyvinyl Chloride (PVC): PVC films have good moisture resistance and can be used in end-uses where durability is key.

[0097] 5. Polypropylene (PP): PP films can also be used for their moisture resistance, and they offer good chemical resistance and tensile strength.MELT SPUN NON-WO VENS

[0098] Melt-spun non-wovens (synthetic fabrics produced by extruding melted polymer fibers that are spun and then cooled to form a web-like material) can be applied to thedisclosed gypsum boards to provide water resistance, improve durability, and enhance mechanical properties, such as tensile strength and impact resistance.

[0099] Suitable melt-spun non-wovens for the disclosed water-resistant gypsum board can include the following nonlimiting examples.

[0100] 1. Polypropylene (PP): Melt-spun PP non-wovens can be used with the disclosed gypsum board and are desirable for their hydrophobic properties. PP formulations can be chemical-resistant and can impart improved tensile and nail-pull properties. Fiber size and density can be adjusted to meet specific performance requirements.

[0101] 2 Polyester (PET): PET non-wovens can be used with the disclosed gypsum board to provide good strength, durability, and chemical resistance. Suitable PET non-wovens can be treated to enhance hydrophobicity, making them appropriate for water-resistant applications.

[0102] 3 Polyethylene (PE): PE non-wovens can provide excellent moisture resistance to the disclosed gypsum board. PE non-wovens can exhibit more flexibility compared to other materials, which may be beneficial depending on the end-use requirements.

[0103] In selecting a melt-spun non-woven for the disclosed water-resistant gypsum board, the following factors can be considered.Water ResistanceBreathabilityDurabilityAdhesionChemical ResistanceCompatibilityEnvironmental ConsiderationsCostCOATED GLASS FIBER MATS

[0104] Coated glass fiber mats can be used as a reinforcement layer in the production of the disclosed gypsum boards. Generally, when the face layer is a glass mat, the glass mat will comprise glass fibers, a resin binder, and a mat coating. Properties such as enhanced moisture and mold resistance, as well as improved durability, can be improved with the inclusion of coat glass fiber mats. These mats can be applied to the face and back of gypsum boards to provide a barrier to water while also increasing the board's structural integrity.

[0105] Examples of suitable coating materials for glass fiber mats to achieve the desired properties include the following.

[0106] 1. Acrylic or Polymer Coating: Mats coated with an acrylic polymer can offer good water resistance while maintaining the breathability of the disclosed board.

[0107] 2. Asphalt or Bitumen Coating: For the disclosed boards, weight and limited breathability of asphalt-coated glass mats may limit application to those end-uses that require robust moisture protection, especially for exterior applications.

[0108] 3. Poly vinylidene Chloride (PVDC): PVDC coatings can be suitable to provide superior moisture barrier properties and chemical resistance to the disclosed board.

[0109] 4. Polyethylene (PE): PE coatings can impart strong moisture resistance. Careful consideration must be given to breathability if selected for the disclosed board.

[0110] 5. Silicone or Other Water-Repellent Treatments: Silicone treatments that neither contain nor evolve formaldehyde can be applied to glass mats to enhance their water-repellent properties without significantly affecting the breathability of the final product.[oni] Factors to consider in the selection of coated glass fiber mat for the disclosed water- resistant gypsum board can include the following.

[0112] Water Resistance: The coating should provide an effective barrier to moisture to protect the gypsum core.

[0113] Vapor Permeability: While water resistance is critical, the mat should also allow the board to breathe, preventing potential moisture buildup within the wall cavity.

[0114] Tensile Strength: The mat should contribute to the overall structural strength of the board, increasing its resistance to breaks and cracks.

[0115] Compatibility: The coated mat should have good compatibility with the gypsum core, ensuring strong adhesion and preventing delamination over time.

[0116] Surface Finish: The mat should provide a suitable surface for receiving paint, plaster, or other decorative treatments without the need for extensive preparation.

[0117] Ease of Installation: The reinforced gypsum board should be easy to cut and install without damaging the mat or compromising its protective properties.

[0118] Environmental Considerations: The environmental impact of the mat's production, as well as its end-of-life disposal or recyclability, should be considered.

[0119] Cost-Effectiveness: The benefits of the coated mat should be balanced against the additional costs to determine its value in enhancing the gypsum board's performance. UNCOATED FIBER GLASS MATS

[0120] The focus is typically on mats that can provide reinforcement and improve the board's mechanical properties. Uncoated glass fiber mats are designed to be embedded into thegypsum core or adhered to the surface to enhance the board's strength, fire resistance, and durability.

[0121] Here are the key characteristics to consider when selecting an uncoated glass fiber mat:

[0122] 1. Fiber Diameter and Length: A finer fiber diameter can lead to a smoother surface finish, which is important for interior wallboards that will be painted or finished. Longer fibers may improve tensile strength and overall durability.

[0123] 2. Mat Weight: The weight of the glass fiber mat (often expressed in grams per square meter, g / m2) can impact the strength and rigidity of the gypsum board. Lightweight mats are typically used for interior applications, while heavier mats might be chosen for more demanding uses, such as exterior sheathing or impact-resistant boards.

[0124] 3. Binder Content: The glass fibers in the mat are held together by a binder. The type and amount of binder used can affect the mat's flexibility, porosity, and compatibility with the gypsum slurry. The binder should be chosen to provide enough integrity during handling and to allow for proper embedding into the gypsum core.

[0125] 4. Porosity and Permeability: The mat should allow for the passage of air and moisture during the drying process of the gypsum slurry, ensuring a strong bond between the mat and the gypsum core without trapping moisture.

[0126] 5. Compatibility with Gypsum Slurry: The mat should be engineered to integrate well with the gypsum slurry, allowing for efficient penetration and adhesion, which results in a strong bond upon setting and drying.

[0127] When selecting an uncoated glass fiber mat, the intended application of the gypsum board should be considered:

[0128] For standard interior wallboard, a lightweight mat with good flexibility and a fine fiber structure may be sufficient.

[0129] For high-impact or high-moisture areas, a mat with greater tensile strength and a heavier weight may be more appropriate.

[0130] For exterior sheathing or shaft liner panels, the mat should have the strength and durability to withstand the elements and provide additional fire resistance.POLYMERIC MATS WITH GLASS FIBERS

[0131] Polymeric mats reinforced with glass fibers are specialized products used in the production of high-performance gypsum boards, offering improved moisture resistance, strength, and durability compared to standard paper-faced gypsum boards. When choosing apolymeric mat with glass fibers for gypsum board applications, there are several options that manufacturers might consider:

[0132] 1. Fiberglass Mat Faced Gypsum Boards: These mats are made from glass fibers bonded together with a resin. They are designed to be highly water-resistant and can also provide enhanced mold and mildew resistance. They are commonly used for exterior sheathing, shaft liners, and tile backers where moisture and mold resistance are critical.

[0133] 2. Composite Mats: Some mats are composites that combine glass fibers with synthetic fibers, such as polyester or polypropylene, to add additional properties. For example, the synthetic fibers may be hydrophobic to increase water resistance, or they might be chosen for their ability to bond well with gypsum.

[0134] 3. Scrim-Reinforced Mats: These are polymeric mats where a lightweight scrim made of woven or non-woven glass fibers is embedded into the mat to provide additional strength and dimensional stability to the gypsum board.

[0135] When selecting a polymeric mat with glass fibers, the characteristics to consider include:

[0136] Moisture Resistance: The mat should offer excellent moisture resistance to protect the gypsum core from water absorption, which can compromise the structural integrity of the board.

[0137] Mold and Mildew Resistance: Materials that are naturally resistant to mold and mildew growth are preferred, especially for applications in high humidity environments.

[0138] Tensile and Impact Strength: The mat should contribute to the overall strength of the board, making it more resistant to impacts, breaks, and cracks.

[0139] Fire Resistance: Glass fibers are inherently fire-resistant, but the polymeric component of the mat should also not compromise the fire-resistant properties of the gypsum board.

[0140] Adhesion to Gypsum: The mat should have good adhesion properties to ensure a strong bond with the gypsum core without delamination.

[0141] Ease of Installation: The reinforced gypsum board should be easy to cut and install and compatible with a variety of finishing treatments like paint, wallpaper, or tile adhesive.

[0142] Environmental Considerations: Assess the environmental impact of the mat's production, as well as its recyclability or disposal options at the end of the product's lifecycle NATURAL FIBER NONWOVENS

[0143] Natural fiber nonwovens offer an eco-friendly alternative to synthetic mats for reinforcing gypsum boards. These types of nonwovens can contribute to the sustainabilityprofile of a building product and may be preferred in green building practices. However, it's important to remember that natural fibers may not inherently provide the same level of moisture resistance as synthetic or glass fiber mats, so additional treatments might be necessary for certain applications.

[0144] Some natural fiber nonwovens that could be considered for gypsum board reinforcement are as follows:

[0145] 1. Wood Fiber Nonwovens: Wood fibers are a common choice for natural fiber mats. They can be made from softwoods or hardwoods and treated to improve their moisture resistance and adhesion to the gypsum core.

[0146] 2. Jute Fiber Nonwovens: Jute is a sustainable, highly renewable fiber with good mechanical properties. It is also relatively inexpensive compared to synthetic fibers. Jute nonwovens can be treated for enhanced performance in gypsum boards.

[0147] 3. Kenaf Fiber Nonwovens: Kenaf fibers are known for their strength and durability. When used in nonwoven mats, kenaf provides reinforcement that can improve the structural properties of gypsum boards.

[0148] 4. Flax Fiber Nonwovens: Flax is another natural fiber with good mechanical properties, including tensile strength. It is sometimes used in composite applications and might be suitable for reinforcing gypsum boards.

[0149] 5. Hemp Fiber Nonwovens: Hemp fibers have high tensile strength and durability, making them a potential candidate for gypsum board applications. Like other natural fibers, hemp can be processed into nonwoven mats.

[0150] 6. Cotton Fiber Nonwovens: Although not as common due to cost and moisture absorption, cotton fibers can be processed into nonwovens and used for reinforcement in certain types of gypsum boards.

[0151] When considering natural fiber nonwovens for gypsum boards, these factors should be taken into account:

[0152] Moisture Resistance: As mentioned earlier, natural fibers typically absorb more moisture than synthetic or glass fibers, so they may need to be treated with water-resistant coatings or additives.

[0153] Mechanical Properties: The nonwoven should provide adequate tensile strength and impact resistance to enhance the durability of the gypsum board.

[0154] Adhesion to Gypsum: The nonwoven mat needs to bond well with the gypsum core, which may require special binder systems or treatments.

[0155] Fire Resistance: While natural fibers are not inherently fireproof, they can be treated with fire retardants to improve their fire resistance.

[0156] Environmental Impact: One of the advantages of natural fibers is their reduced environmental footprint, which can contribute to LEED certification or other green building standards. The sustainability of the fiber source, as well as the manufacturing process, should be considered.

[0157] Cost: Natural fiber nonwovens may vary in price, so it's important to balance performance characteristics with cost-effectiveness.

[0158] Before selecting a natural fiber nonwoven, it's crucial to perform testing to ensure that it meets the required performance standards, especially regarding moisture resistance and adhesion to the gypsum core.NONWOVEN AND WOVEN GLASS OR POLYMERIC SCRIMS

[0159] When choosing nonwoven or woven glass or polymeric scrims for gypsum board reinforcement, the selection largely depends on the specific requirements of the board, such as its intended use, required strength, fire resistance, and moisture resistance. Scrims provide dimensional stability, impact resistance, and help to control cracking.

[0160] Some options and considerations for scrims in gypsum board applications are as follows:Glass Fiber Scrims:

[0161] Glass fiber scrims offer excellent strength, durability, and fire resistance, making them a popular choice for gypsum board reinforcement.

[0162] 1. Woven Glass Fiber Scrims: These scrims provide high tensile strength and dimensional stability due to the orderly arrangement of the fibers. They can be selected based on weave density and yarn thickness to meet the specific strength requirements.

[0163] 2. Nonwoven Glass Fiber Scrims: While typically providing less strength than woven scrims, nonwoven glass fiber scrims can be easier to integrate into the gypsum matrix due to their random fiber orientation and can still offer considerable reinforcement.POLYMERIC SCRIMS:

[0164] Polymeric scrims, typically made from materials like polyester or polypropylene, are lighter and can offer resistance to biological growth and chemicals. They are not as inherently fire-resistant as glass fiber but can be treated with fire retardants.

[0165] 1. Woven Polymeric Scrims: These scrims provide good tensile strength and more flexibility compared to glass fiber. They are especially useful when the board needs to be more resistant to cracking upon impact or flexing.

[0166] 2. Nonwoven Polymeric Scrims: Offering a random fiber orientation, these scrims can enhance the overall toughness of the gypsum board and are often used in conjunction with other reinforcing materials.Considerations for Selecting Scrims:

[0167] Mechanical Properties: Choose a scrim based on the required tensile strength, elongation, and tear resistance.

[0168] Compatibility with Gypsum: The scrim should adhere well to the gypsum slurry and maintain its integrity during the board's setting and drying processes.

[0169] Moisture Resistance: For applications where moisture resistance is crucial, select a scrim that does not absorb water or degrade in humid conditions, or ensure it is adequately treated.

[0170] Fire Resistance: Glass fiber scrims are inherently fire-resistant, while polymeric scrims may need additional fire-retardant treatments.

[0171] Ease of Installation: Consider how the scrim affects the cutting, scoring, and fastening of the gypsum board during installation.

[0172] Environmental Considerations: Evaluate the environmental impact of the scrim material, including its production process and end-of-life recyclability.

[0173] Cost-Effectiveness: Balance the performance benefits of the scrim against its cost to ensure its economic viability for the intended application.SPUN BOND NONWOVENS:

[0174] For a gypsum board application where good moisture resistance is a key requirement, spun bond nonwovens made from polypropylene (PP) or polyester (PET) are recommended due to their hydrophobic properties and suitability for use in construction materials where durability and resistance to water are important.POLYPROPYLENE (PP) SPUN BOND NONWOVENS:

[0175] PP nonwovens are widely used in various applications due to their excellent moisture resistance, chemical resistance, and overall durability. The hydrophobic nature of polypropylene makes it particularly suitable for environments where the presence of moisture is a concern. PP spun bond nonwovens are also resistant to mold and mildew growth, which is advantageous for indoor air quality and structural integrity of the board.POLYESTER (PET) SPUN BOND NONWOVENS:

[0176] PET nonwovens also exhibit good moisture resistance and have the added benefit of higher tensile strength compared to PP. They can be treated to enhance specific properties,such as fire resistance and adhesion to gypsum. PET nonwovens have good thermal stability and are suitable for applications where the material might be exposed to higher temperatures.

[0177] When selecting a spun bond nonwoven for gypsum boards, properties to be considered include:

[0178] Moisture Resistance: The nonwoven must repel water effectively to protect the gypsum core from moisture penetration.

[0179] Bond Strength: The material should have good compatibility with gypsum to ensure a strong bond during the board manufacturing process.

[0180] Dimensional Stability: The nonwoven should maintain its dimensions and not stretch or shrink excessively under normal conditions, which can cause issues during installation or use.

[0181] Mold and Mildew Resistance: The nonwoven should not support the growth of mold or mildew, which is important for indoor air quality and product longevity.

[0182] Durability: The nonwoven should contribute to the overall durability of the gypsum board, making it resistant to wear and tear during handling and installation.

[0183] Environmental Impact: Consider the sustainability aspect of the nonwoven, including its production process, recy cl ability, and overall environmental footprint. HYDROENTANGLED NONWOVENS

[0184] Hydroentangled (also known as spunlaced) nonwovens are created using high- pressure waterjets that entangle the fibers together, resulting in a fabric with a soft hand and cloth-like texture. For gypsum board applications where good moisture resistance is important, you would typically look for hydroentangled nonwovens made from synthetic fibers that have inherent water-repelling properties.

[0185] The most suitable hydroentangled nonwovens for moisture-resistant gypsum boards would usually be those made from:

[0186] 1. Polypropylene (PP) Fibers: Polypropylene is naturally water-resistant, does not absorb water, and is less susceptible to mold and mildew growth. A hydroentangled nonwoven made from PP fibers would offer a good barrier against moisture while maintaining the mechanical properties needed for gypsum board reinforcement.

[0187] 2. Polyester (PET) Fibers: Polyester is another synthetic fiber with good moisture resistance. PET nonwovens can also be treated for additional properties such as enhanced fire resistance and improved bonding to gypsum.

[0188] When selecting a hydroentangled nonwoven for this application, consider the following factors:

[0189] Moisture Barrier: The nonwoven must provide an effective moisture barrier to protect the gypsum core from water damage.

[0190] Bonding with Gypsum: The nonwoven should be able to form a strong and durable bond with the gypsum material during production.

[0191] Tensile Strength: The nonwoven should contribute to the overall strength of the gypsum board, particularly in terms of resistance to tearing and puncturing.

[0192] Mold and Mildew Resistance: Given that moisture resistance is a priority, the nonwoven should not support the growth of mold or mildew.

[0193] Dimensional Stability: The fabric should retain its dimensions during the manufacturing process and under changing environmental conditions.

[0194] Surface Compatibility: The external surface of the gypsum board should be suitable for finishing treatments, such as painting or wallpaper application.

[0195] Environmental Considerations: Evaluate the sustainability of the nonwoven, including its lifecycle impact and end-of-life disposal or recycling options.NONWOVENS WITH ASPECT RATIO LAYERING

[0196] In the context of gypsum board manufacturing, nonwovens with aspect ratio layering refers to the structure of the fabric in which fibers are oriented or layered in a way to optimize their length-to-diameter (aspect ratio) for enhanced mechanical properties. Nonwovens designed with a focus on aspect ratio layering can provide improved tensile strength, tear resistance, and other properties that are beneficial to gypsum boards.

[0197] For nonwovens with aspect ratio layering in gypsum boards, the following types of nonwovens are typically considered:

[0198] 1. Multilayer Nonwovens: These are constructed with multiple layers where each layer could be designed to perform a specific function. For instance, layers with higher aspect ratio fibers could be placed where tensile strength is most needed, while lower aspect ratio fibers could be used in layers intended for improved bonding and coverage.

[0199] 2. Directionally Oriented Nonwovens: Some nonwovens are manufactured with fibers predominantly oriented in one direction, which provides greater strength in that orientation. This can be useful in applications where the board is expected to bear loads or stresses more in one direction than another.

[0200] 3. Hybrid Nonwovens: These are designed by combining different types of fibers or structures to exploit the advantages of each. For example, a hybrid nonwoven could integrate high aspect ratio synthetic fibers for strength with natural fibers for sustainability.

[0201] When recommending a nonwoven with aspect ratio layering for gypsum boards, one must consider the manufacturing capabilities, the intended application of the gypsum board, and the specific performance requirements it needs to meet.

[0202] Here's what to look for in nonwovens for this purpose:

[0203] Fiber Orientation: The orientation of fibers plays a large role in the mechanical properties of the nonwoven. Horizontal or vertical orientation can be chosen based on the load-bearing requirements.

[0204] Fiber Type and Properties: High-performance synthetic fibers like glass, polyester, or polypropylene may be chosen for layers requiring moisture resistance and strength.

[0205] Layer Configuration: The design of the layers should be such that it provides the necessary strength, flexibility, adhesion, and moisture resistance required for the gypsum board.

[0206] Bonding Technique: The method used to bond layers together (e.g., thermal bonding, needle punching, chemical bonding) must maintain the integrity of the aspect ratios while providing a durable bond.

[0207] Compatibility with Gypsum: The nonwoven should bond well with the gypsum slurry during manufacturing and not interfere with the setting process.MOISTURE RESISTANCE ADDITIVE

[0208] Suitable moisture-resistant additives include formaldehyde free additives such as waxes (linear, cross-liked, branched, or charged), water-resistant polymers, molecules when added can polymerize in-situ, metallic stearates, and any combination thereof.

[0209] Examples of suitable linear waxes include paraffin or microcrystalline waxes for enhancing the moisture resistance of gypsum boards. These linear waxes can be used as effective hydrophobic agents because they can be applied to the gypsum core or incorporated into the paper facing.

[0210] Paraffin waxes, which are a mixture of saturated hydrocarbons, are known for their excellent water-repellent properties. They can be applied through a variety of methods, including impregnation or coating, to provide a moisture barrier. Their chain lengths and melting points can be selected based on the specific requirements of the gypsum board application.

[0211] Microcrystalline waxes, which have a higher melting point and a more branched structure compared to paraffin waxes, offer good adhesion to various substrates and can also enhance water resistance. They are often used in applications that require a more robust moisture barrier.

[0212] In an embodiment, the moisture resistance additive is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 10 percent, by weight. In certain embodiments, the moisture resistance additive is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 0.5 percent, by weight. In some embodiments, the moisture resistance additive is present in the relevant gypsum layer or slurry in an amount of about 0.05 percent to about 0.2 percent, by weight. In some embodiments, the moisture resistance additive is present in the relevant gypsum layer or slurry in an amount of about 1 Ib / msf to about 50 Ib / msf, for a gypsum panel having a thickness of about 14 inch to about 1 inch.

[0213] In an embodiment, the moisture resistance additive is present in each gypsum layer. In an embodiment, the moisture resistance additive is present in the gypsum core. In an embodiment, the moisture resistance additive is present in one or two slate coat layers. In an embodiment, the moisture resistance additive is not present in the gypsum core. In an embodiment, the moisture resistance additive is not present in one or two slate coat layers. Charged waxes

[0214] In the context of gypsum board manufacturing, the use of charged waxes — specifically cationic waxes — is an effective way to enhance the moisture resistance of gypsum boards. These waxes are positively charged, which enables them to adhere well to the negatively charged cellulosic fibers in the paper facing of gypsum boards.

[0215] When selecting a charged wax, the following criteria should be considered:

[0216] 1. Compatibility: The charged wax should be compatible with the gypsum slurry and other additives to ensure it does not adversely affect the setting time or the strength of the board.

[0217] 2. Charge Density: The charge density of the wax should be sufficient to ensure good adhesion to the paper facing and to disperse appropriately in the gypsum slurry.

[0218] 3. Melting Point: The wax should have a suitable melting point that allows it to be easily processed during manufacturing but high enough to maintain its properties under expected conditions of use.

[0219] 4. Environmental Considerations: The environmental impact of the wax, including its biodegradability and any potential regulatory concerns, should be assessed.

[0220] 5. Cost-Effectiveness: The chosen wax should provide the desired performance benefits without significantly increasing the overall cost of the gypsum board.

[0221] Cationic emulsions of waxes are often used because the positive charge enhances their retention on the negatively charged surfaces of the paper fibers. These emulsions can besprayed onto the paper or added to the gypsum slurry. The improved adhesion helps to create a water-repellent layer, reducing the absorption of moisture into the paper and the gypsum core.

[0222] Branched waxes are often used to improve moisture resistance while maintaining good processability. These waxes have non-linear molecular structures that can enhance the water-repellent properties of the board by creating a more complex matrix that hinders water penetration.

[0223] Two common types of branched waxes used in the gypsum board industry are:

[0224] 1. Polyethylene Waxes: These are synthetic waxes with a branched structure that can provide excellent water resistance. They are available in various molecular weights and can be modified to enhance their compatibility with gypsum. High-density polyethylene (HDPE) waxes are a specific type used for this application.

[0225] 2. Microcrystalline Waxes: As mentioned earlier, microcrystalline waxes have branched hydrocarbon chains and are more flexible and adhesive than paraffin waxes. They have higher melting points, which is beneficial for processing and maintaining integrity at higher temperatures.Cross-linked Waxes

[0226] Cross-linked waxes can be suitable for use in the disclosed gypsum products. The standard approach for improving moisture resistance in gypsum boards generally involves the use of wax emulsions, which may include paraffin, microcrystalline, or polyethylene waxes. These waxes are not cross-linked but instead are used in a linear or branched form.

[0227] Cross-linking refers to the process of chemically joining two or more molecules by a covalent bond. In the disclosed cross-linked wax, cross-linking can be used to selectively alter the physical properties of the wax, making it more rigid or changing its melting behavior, which could affect its efficacy as a water repellent and its processability.

[0228] Cross-linked waxes can be suitable for use in the disclosed gypsum products to create a three-dimensional network that provides a durable, water-resistant barrier. Examples of suitable cross-linked waxes include [fill in the blank], merely to name a few.Dispersants

[0229] Dispersants for the disclosed formaldehyde free gypsum product can include formaldehyde free additives, nonlimiting examples of which include polycarboxylate ethers, polycarboxylate esters, polystyrene sulfonates, and lignin-based dispersants along with combinations of these examples.

[0230] Polycarboxylate ethers or esters (PCEs) can be suitable dispersants for the disclosed gypsum products to improve workability and strength by reducing the water content without affecting the hydration process. In gypsum board manufacturing, the role of a dispersant is to improve the flow properties of the gypsum slurry, ensuring a more uniform fill and reducing the amount of water needed.

[0231] In the disclosed gypsum products, PCEs can reduce viscosity and improve the flow of stucco slurries, improving ease of processing and manufacturing the gypsum products. PCEs are known for their effectiveness at low dosages, excellent dispersing properties, and ability to provide high slump retention.

[0232] Polystyrene sulfonates are a type of superplasticizer often used as dispersants in a variety of applications due to their ability to improve the flow of materials. In the context of gypsum board manufacturing, dispersants are important for achieving a homogeneous gypsum slurry, which is critical for producing boards with uniform properties and quality.

[0233] Sodium polystyrene sulfonate (PSS) is one example of a polystyrene sulfonate suitable for use in the disclosed gypsum products. It is water-soluble and known for its ability to disperse particles effectively, which in turn can reduce the water demand of the slurry and improve the flowability without compromising the setting time or the strength of the final product.

[0234] Lignin-based dispersants, particularly lignosulfonates, can be suitable for use in the disclosed gypsum products. Lignin-based dispersants can be favored for their costeffectiveness and sustainability. These dispersants can be derived from the sulfite pulping process of wood and can be utilized in the formulation of gypsum products to improve the workability of the gypsum slurry.

[0235] The dosage of the dispersant can be adjusted to improve adsorption of water onto the surface of gypsum particles, providing a steric barrier that keeps particles apart, thus reducing the water demand and improving the flow properties of the slurry. With a moderate amount of trial and error, dosage can be adjusted to provide improved properties including a smoother finish, better board quality, and potentially lower manufacturing costs due to reduced water usage and faster drying times.

[0236] In an embodiment, the dispersant is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 10 percent, by weight. In certain embodiments, the dispersant is present in the relevant gypsum layer or slurry in an amount of about 0.01 percent to about 0.5 percent, by weight. In some embodiments, the dispersant is present in the relevant gypsum layer or slurry in an amount of about 0.05 percent to about 0.2 percent, byweight. In some embodiments, the dispersant is present in the relevant gypsum layer or slurry in an amount of about 1 Ib / msf to about 50 Ib / msf, for a gypsum panel having a thickness of about 14 inch to about 1 inch.

[0237] In an embodiment, the dispersant is present in each gypsum layer. In an embodiment, the dispersant is present in the gypsum core. In an embodiment, the dispersant is present in one or two slate coat layers. In an embodiment, the dispersant is not present in the gypsum core. In an embodiment, the dispersant is not present in one or two slate coat layers.

[0238] The skilled artisan can adjust dosage of the disclosed dispersant (alone or in combination with other known dispersants along with those disclosed herein) taking into consideration factors such as the following.

[0239] 1. Reduction in Water Demand: Effective lignin-based dispersants will enable you to reduce the amount of water needed to achieve a workable slurry, thereby improving the drying process and final product quality.

[0240] 2. Consistency and Performance: The lignin-based dispersant should provide consistent performance, ensuring that it does not adversely affect the setting time or the board's mechanical properties.

[0241] 3. Compatibility: The dispersant must be compatible with other additives in the formulation, such as accelerators, retarders, moisture-resistant additives, and starches, without causing any adverse interactions.

[0242] 4. Source and Quality: Lignin-based dispersants, such as lignosulfonates, are available in various grades and from multiple sources. The purity, molecular weight, and degree of sulfonation (for lignosulfonates) can affect their performance as dispersants.

[0243] 5. Sustainability: Some lignin-based dispersants are a byproduct of the paper industry and are often favored for their renewable nature and contribution to the circular economy.

[0244] 6. Cost-Effectiveness: The dispersant's cost relative to the benefits it provides, including potential savings from reduced water usage, should justify its inclusion in the manufacturing process.

[0245] For example, with respect to compatibility, using PCE dispersant can save water, which reduces the global warming potential (GWP) of the product. However, PCE dispersants may exhibit compatibility issues with certain moisture-resistant additives, like siloxane. If a wax is used as the moisture-resistant additive, instead of siloxane, in conjunction with PCE, a synergistic effect is achieved, allowing for water / GWP reduction, while making both components formaldehyde-free.EXAMPLES

[0246] Experimental setup

[0247] Gypsum panels containing raw materials as well as other typical gypsum panel making additives (fiberglass, starch, dextrose, boric acid, etc.) are placed in a laboratory scale press. The lab press is fitted with a caul to create a seal around the press system to permit collection of VOCs. The sealed caul plate contains inlet and outlet ports to permit the controlled collection of the emitted VOCs. VOCs within the collected air stream are removed and the released formaldehyde is quantified via instrumental analysis. The setup and analysis is performed according to ASTM D7770-12(2019), but other methods of VOC detection may be used.

[0248] Example 1: Detection of formaldehyde released from prior art gypsum panels

[0249] A 16”xl6” formaldehyde-containing gypsum panel is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. It is found that formaldehyde is constantly released from the panel throughout this time period.

[0250] Example 2: Detection of formaldehyde released from gypsum panels of the invention

[0251] A 16”xl6” formaldehyde free gypsum product according to the invention is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0252] Example 3: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from cellulose-based materials with water-resistant and weatherable coatings, and linear waxes as a water- resistant additive

[0253] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ether, a liner made from cellulose-based materials with water-resistant and weatherable coatings, and linear waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0254] Example 4: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from extruded polymer fdms, and cross-linked waxes as a water-resistant additive

[0255] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ester, a liner made from extruded polymer films, and cross-linked waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested atroom temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0256] Example 5: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from melt-spun non-w ovens, and branched waxes as a water-resistant additive

[0257] A 16”xl6” formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from melt-spun non-wovens, and branched waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0258] Example 6: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from coated glass fiber mats, and charged waxes as a water-resistant additive

[0259] A 16”xl6” formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from coated glass fiber mats, and charged waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0260] Example 7: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from uncoated fiber glass mats, and water-resistant polymers as a water-resistant additive

[0261] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ether, a liner made from uncoated fiber glass mats, and water-resistant polymers as a water- resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0262] Example 8: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from polymeric mats with glass fibers, and molecules that when added can polymerize in-situ as a water-resistant additive

[0263] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ester, a liner made from polymeric mats with glass fibers, and molecules that when added can polymerize in-situ as a water-resistant additive is placed in a lab press according to the setupdescribed above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0264] Example 9: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from natural fiber nonwovens, and metallic stearates as a water-resistant additive

[0265] A 16”xl6” formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from natural fiber nonwovens, and metallic stearates as a water- resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0266] Example 10: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from nonwoven and woven glass or polymeric scrims, and linear waxes as a water-resistant additive

[0267] A 16”xl6” formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from nonwoven and woven glass or polymeric scrims, and linear waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0268] Example 11: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from spun bond nonwovens, and cross-linked waxes as a water-resistant additive

[0269] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ether, a liner made from spun bond nonwovens, and cross-linked waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0270] Example 12: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from hydroentangled nonwovens, and branched waxes as a water-resistant additive

[0271] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ester, a liner made from hydroentangled nonwovens, and branched waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0272] Example 13: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from nonwovens with aspect ratio layering, and charged waxes as a water-resistant additive

[0273] A 16”xl6” formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from nonwovens with aspect ratio layering, and charged waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0274] Example 14: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from other coated nonwovens, and water-resistant polymers as a water-resistant additive

[0275] A 16”xl6” formaldehyde-free gypsum board manufactured with lignin-based dispersants, a liner made from other coated nonwovens, and water-resistant polymers as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0276] Example 15: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from cellulose-based materials with water-resistant and weatherable coatings, and molecules that when added can polymerize in-situ as a water-resistant additive

[0277] A 16”xl6” formaldehyde-free gypsum board manufactured with a polycarboxylate ether, a liner made from cellulose-based materials with water-resistant and weatherable coatings, and molecules that when added can polymerize in-situ as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0278] Example 16: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with a polycarboxylate ester, a liner made from extruded polymer fdms, and metallic stearates as a water-resistant additive

[0279] A 16”xl6” formaldehyde-free gypsum board manufactured with a poly carboxylate ester, a liner made from extruded polymer films, and metallic stearates as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0280] Example 17: Detection of formaldehyde released from a formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from melt-spun non-w ovens, and linear waxes as a water-resistant additive

[0281] A 16”xl6” formaldehyde-free gypsum board manufactured with polystyrene sulfonates, a liner made from melt-spun non-wovens, and linear waxes as a water-resistant additive is placed in a lab press according to the setup described above. The panel is tested at room temperature and at 35°C, each for a period of 72 hours. No formaldehyde is detected as emitted from the panel during this time.

[0282] Many modifications and other embodiments set forth herein will come to mind to one skilled in the art to which this subject matter pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practicing the subject matter described herein. The present disclosure is in no way limited to just the methods and materials described.

Claims

What is claimed:

1. A formaldehyde free gypsum product comprising: a) gypsum; b) a moisture-resistant additive; c) a dispersant; and d) a liner.

2. The formaldehyde free gypsum product of claim 1 wherein the moisture-resistant additive is selected from the group consisting of waxes, water-resistant polymers, and monomers or oligomers that polymerize in-situ.

3. The formaldehyde free gypsum product of claim 1 wherein the moisture-resistant additive is a stearate.

4. The formaldehyde free gypsum product of claim 3 wherein at least one stearate comprises a metallic stearate.

5. The formaldehyde free gypsum product of claim 1 further comprising at least one wax.

6. The formaldehyde free gypsum product of claim 5 wherein the wax comprises at least one of linear, cross-liked, branched and charged waxes.

7. The formaldehyde free gypsum product of claim 3 wherein the moisture-resistant additive comprises one or more compounds that polymerize after contact with gypsum stucco slurry.

8. The formaldehyde free gypsum product of claim 1 wherein the moisture-resistant additive is selected from the group consisting of linear waxes, cross-linked waxes, branched waxes, charged waxes, water-resistant polymers, polymers that can polymerize in-situ, and stearates.

9. The formaldehyde free gypsum product of claim 1 wherein the dispersant is selected from the group consisting of polycarboxylate ethers, polycarboxylate esters, polystyrene sulfonates, lignin-based dispersants and mixtures of one or more of these.

10. The formaldehyde free gypsum product of claim 9 wherein the polystyrene sulfonate comprises sodium polystyrene sulfonate (PSS).

11. The formaldehyde free gypsum product of claim 9 wherein the lignin-based dispersant comprises a lignosulfonate.

12. The formaldehyde free gypsum product of claim 10, wherein the lignosulfonate is selected from the group consisting of aluminum lignosulfonate, ammonium lignosulfonate,calcium lignosulfonate, copper lignosulfonate, magnesium lignosulfonate, potassium lignosulfonate, sodium lignosulfonate, and zinc lignosulfonate.

13. The formaldehyde free gypsum product of claim 1, wherein the dispersant is selected from the group consisting of a polycarboxylate ether, a polycarboxylate ester, polystyrene sulfonates, and lignin-based dispersants.

14. The formaldehyde free gypsum product of claim 1 wherein the liner comprises a cellulose-based material.

15. The formaldehyde free gypsum product of claim 14 wherein the cellulose-based material further comprises a water-resistant coating.

16. The formaldehyde free gypsum product of claim 15 wherein the water-resistant coating further comprises a weatherable coating.

17. The formaldehyde free gypsum product of claim 14 wherein the liner comprises at least one of: a) a melt spun non-woven; b) a coated glass fiber mat; c) an uncoated fiber glass mat; d) a polymeric mat with glass fibers; e) a natural fiber nonwoven; f) a nonwoven or woven glass or polymeric scrims; g) a spun bond nonwoven; h) a hydroentangled nonwoven; and i) a nonwoven with aspect ratio layering.

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