WO2025235997A1

WO2025235997A1 - Fire resistant coating composition and making and using same

Info

Publication number: WO2025235997A1
Application number: PCT/US2025/028940
Authority: WO
Inventors: Yves Cordeau; Paul PUCKETT; Lei Zhao
Original assignee: Avient Corp
Current assignee: Avient Corp
Priority date: 2024-05-10
Filing date: 2025-05-12
Publication date: 2025-11-13
Anticipated expiration: 2026-11-10

Abstract

Coating compositions prepared from an aqueous formulation of (1) one or more metal silicates, (2) one or more metal oxides, (3) one or more water soluble caustic agents; and (4) water are disclosed to form fire resistant coatings. In some implementations, the coating composition can be free of, or substantially free of, large solid particles comprised of the metal silicate, metal oxide and water-soluble caustic agent.

Description

FIRE RESISTANT COATING COMPOSITION AND MAKING AND USING SAME

CLAIM OF PRIORITY

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/645,769 bearing Attorney Docket Number 1202409 and filed on May 10, 2024, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure is directed to coating compositions that can be formed from (1) one or more metal silicates, (2) one or more metal oxides, (3) one or more water soluble caustic agents; and (4) water. Such coating compositions can form a fire resistant (FR) barrier coating when applied to a substrate.

BACKGROUND

[0003] Many items used in the construction industry are composed of inherently flammable materials including, for example, poles, beams, decking, walls, etc. Many of these materials can be broadly classified as cellulosic (e.g., wood products) and organic polymeric (e.g., thermoplastic and thermoset products). All organic materials (i.e., carbon-containing materials) can degrade thermolytically and/or combust at sufficiently high temperature in the presence of air. Some ways to mitigate the combustibility of such materials are to add chemical components into the material to resist combustion or to coat the materials to slow the migration of heat and oxygen into a part and hinder the release of flammable fragments from the part.

[0004] Geopolymers with fire and heat resistant properties have been used to coat building construction components. See WO2018026714, WO2016/016385. Such coating formulations are applied as slurries or as compositions including aggregates or other large particle solids.

[0005] However, there is a continuing need to improve the resistance to combustibility of certain construction items, as well as other materials, along with improving manufacturability and costs.

SUMMARY OF THE DISCLOSURE

[0006] Advantages of the present disclosure include compositions and kits that can be prepared and used in forming fire-resistant coatings on a variety of substrates. Coatings prepared from the compositions of the present disclosure can also advantageously improve weather-resistance and/or corrosion resistance of the underlying substrate.

[0007] In certain aspects, a fire resistant coating composition can comprise an aqueous formulation prepared from: (1) a metal silicate; (2) a metal oxide; (3) a water-soluble caustic agent; and (4) water. It is understood that a metal hydroxide (i.e., a hydrated form of the metal oxide) can be used in place of a metal oxide in the present disclosure. Advantageously, the aqueous formulation of the present disclosure can be free of, or substantially free of, large solid particles comprised of the metal silicate, metal oxide and water-soluble caustic agent. Limiting the solid particle content and/or size of solid particles in the aqueous formulation allows a fire resistant coating composition to be applied as one or more thin layers and/or applied by an liquid atomizer or liquid aerosol spray. Further, the aqueous formulation of the present disclosure advantageously can have all of the components that react to form a geopolymer matrix (e.g., metal silicate, metal oxide, water-soluble caustic agent, and other reactive components) dissolved or substantially dissolved in the formulation to allow formation of thin coating layers from such a formulation.

[0008] In other aspects, a kit can comprise components of: (1) a metal silicate; (2) a metal oxide; (3) a water-soluble caustic agent; and (4) water. The kit can comprise one or more of the components isolated from another component. Further, the kit can include one or more optional components together or isolated from one or another component.

[0009] In still further aspects, the fire resistant coating composition can be formed by combining: (1) a metal silicate; (2) a metal oxide; (3) a water soluble caustic agent; and (4) water to form the composition. The components can be combined with sufficient water soluble caustic agent to dissolve or substantially dissolve the metal silicate and metal oxide in the formulation.

[0010] In other aspects, a fire resistant coating can be formed from compositions of the present disclosure by applying the composition to a substrate and drying the applied composition on the substrate to cure the composition into a fire resistant coating on the substrate. Advantageously, the coating composition can be applied by spraying the composition onto the substrate as an aerosol. Alternatively, or in addition thereto, the coating composition can be applied by dip coating, rolling, brushing, etc. Further, the coating composition can be applied to form one or more coating layers in which each layer can have a thickness in the range of 1- 50 mils (25 pm to 1,270 pm). In some implementations, the applied coating composition can be dried in air at a temperature of from about 5 °C to about 50 °C or can be dried by exposing the applied composition to heat at a temperature of from about 50 °C to about 500 °C.

[0011] Implementations of the present disclosure include one or more of the following features individually or combined. For example, the coating composition can further comprise optional components such as: (5) one or more catalysts or activators; (6) one or more pigments; (7) one or more rheology modifiers; (8) one or more ceramic particles; (9) one or more fibers; (10) one or more surfactants; or any combination thereof. Certain of these components may or may not be soluble in the composition and may be solid components of the coating composition.

[0012] In some implementations, the metal silicate comprises one or more of: an alkali metal silicate, sodium silicate, neosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, tectosilcates, Mullite, Kaolinite, Muscovite, or any combination thereof. In other implementations, the metal oxide comprises one or more of: aluminum trihydrate (ATH), zinc oxide (ZnO), iron oxide, titanium dioxide (TiO2), copper oxide, zirconium oxide, manganese oxide, nickel oxide, silver oxide, vanadium oxide, bismuth oxide, or any combination thereof. Further, the metal oxide can be used as the hydrated (hydroxy) form of itself. In still further implementations, the water soluble caustic agent comprises one or more of: an alkali metal hydroxide, Na2O(SiC>2), or ammonium hydroxide.

[0013] Additional advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only certain embodiments are shown and described, simply by way of illustration of carrying out certain subject matter. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 is a x-ray diffraction (XRD) spectra of sodium silicate.

[0015] Fig. 2 is a XRD spectra of a sample of a coating prepared from one or more fire resistant coating composition of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE [0016] The disclosure may be more fully appreciated by reference to the following description, including the following definitions and examples. Certain features of the disclosed compositions and methods which are described herein in the context of separate aspects, may also be provided in combination in a single aspect. Alternatively, various features of the disclosed compositions and methods that are, for brevity, described in the context of a single aspect, may also be provided separately or in any sub-combination.

[0017] Unless otherwise defined herein, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0018] As employed above and throughout the disclosure, the following terms and abbreviations, unless otherwise indicated, shall be understood to have the following meanings.

[0019] As used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0020] As used in the specification including the appended claims, when a range of values is expressed, such range includes from the one particular value and/or to the other particular value. All ranges are inclusive and combinable. Further, reference to values stated in ranges includes each and every value within that range. The term “about” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass reasonable variations of the value.

[0021] The present disclosure is directed to compositions and kits for such compositions that can form fire resistant coatings. Advantageously, the fire resistant coating compositions and kits of the present disclosure can be composed of relatively low cost components and can be readily applied to a variety of substrate surfaces. The coating composition can bond to the surface as it dries to form a fire resistant (FR) barrier coating. Coatings prepared from the compositions of the present disclosure can advantageously improve weather-resistance and/or corrosion resistance of the underlying substrate.

[0022] In certain aspects, a fire resistant coating composition of the present disclosure can comprise an aqueous formulation prepared from: (1) a metal silicate; (2) a metal oxide; (3) a water- soluble caustic agent; and (4) water. An advantage of the aqueous formulation of the present disclosure is that it generally can be free of, or substantially free of, aggregate or other large solid particles. For example, the coating composition can be free of, or substantially free of, large solid particles comprised of the metal silicate, metal oxide and water-soluble caustic agent. Limiting the solid particle content and/or size of solid particles in the aqueous formulation allows a fire resistant coating composition to be applied as one or more thin layers and/or applied by an liquid atomizer or liquid aerosol spray. Further, the aqueous formulation of the present disclosure advantageously can have all of the components that react to form a geopolymer matrix (e.g., metal silicate, metal oxide, water-soluble caustic agent, and other reactive components) dissolved or substantially dissolved in the formulation to allow formation of thin coating layers from such a formulation.

[0023] In certain aspects, the fire resistant coating composition of the present disclosure includes no more than 10 weight percent (wt%) of solid particles in the formulation based on the total weight of the formulation and when the formulation is at a temperature of 25 °C . For example, a fire resistant coating composition of the present disclosure can include no more than 9 wt%, 8 wt%, 6 wt% 4 wt%, 2 wt% or less of solid particles in the formulation based on the total weight of the formulation and when the formulation is at a temperature of 25 °C. That is, in some implementations, the fire resistant coating composition or aqueous formulation is free of, or substantially free of, solid particles comprised of the metal silicate, metal oxide and water-soluble caustic agent having no more than 10 wt% of such solid particles based on the total weight of the composition or formulation at a temperature of 25 °C, e g., no more than 8 wt%, 6 wt% 4 wt%, 2 wt% or less of solid particles. In other implementations, the composition or formulation is free of, or substantially free of, any type of solid particles in such amounts.

[0024] In another aspect of the present disclosure, the fire resistant coating composition and/or aqueous formulation can exclude solid particles (e.g., the metal silicate, metal oxide and water- soluble; or any type of solid particles) having a median diameter of greater than 10 pm, e.g., having median diameter of no more than 9 pm, 8 pm, 7 pm, 5 pm, 3 pm, 2 pm, or no greater than 1 pm, when the composition or aqueous formulation is at a temperature of 25 °C. The median diameter, or D50 value, may be determined via dynamic light scattering. In some implementations, the fire resistant coating composition of the present disclosure can be a solution of its components at a temperature of 25 °C with no detectible solid particles as determined by filtering the solution through a 0.5 pm filter at a temperature of 25 °C or by an equivalent determination. [0025] In other implementations, the fire resistant coating composition of the present disclosure can include optional components such as: (5) one or more catalysts or activators, e.g., carbonates or bicarbonates, phosphate acids and partial acids, or organic carboxylic acids to modify time of cure and/or reactivity of the formulation components; (6) one or more pigments, e.g., to adjust color; (7) one or more rheology modifiers; (8) one or more ceramic particles such as ceramic spheres, Zeeospheres, Carborundum (SiC), AI2O3, etc.; (9) one or more fibers such as those composed of cellulose or cellulose derivatives, jute, coir, a polyamide, polyethylene terephthalate, acrylic, modacrylic, polyacrylonitrile, polyvinylalcohol, basalt, glass, quartz, carbon, etc.; (10) one or more surfactants; or any combination thereof. Certain of these components may or may not be soluble in the composition and may be solid components of the coating composition.

[0026] However, in some implementations, the fire resistant coating composition or aqueous formulation is free of, or substantially free of, solid particles comprised of the metal silicate, metal oxide and water-soluble. In these or other implementations, the fire resistant coating composition or aqueous formulation is free of, or substantially free of, solid particles comprised of aluminosilicate minerals. For example, the fire resistant coating composition or aqueous formulation is free of, or substantially free of aluminosilicate minerals such as metakaolin, fly ash, mullite, akolinite, or muscovite. Those skilled in the art will appreciate that solid particles of aluminosilicates minerals are used in traditional geopolymers. Those solid particles do not substantially dissolve in the formation of a geopolymer and become bonded aggregates in a traditional geopolymer formulation.

[0027] The amounts of the components used to form the aqueous formulation can be adjusted for ease of application of the formulation to a substrate and the desired characteristics of the formed coating. For example, the fire resistant coating composition can have a weight ratio of the metal silicate to metal oxide ranging from about 5: 1 to 1 :5, e.g., from about 4.5:1, 4:1, 3.5: 1, 3: 1, 2.5: 1, 2: 1, 1.5:1, 1 :1 to 1 :1, 1 :1.5, 1 :2, 1 :2.5, 1 :3, 1 :3.5, 1 :4, 1 :4.5, and any value thereof or therebetween. For example, the fire resistant coating composition can have a weight ratio of the metal silicate to metal oxide ranging from about 1 : 1 to about 1 :3 for rapid curing formulations and from about 3 : 1 to about 1.5:1 to form very thin coatings. In some implementations the aqueous formulation includes, based on the total weight of the aqueous formulation, 10% to 45% of the (1) metal silicate; 5% to 65% of the (2) metal oxide; 5% to 30% of the (3) water soluble caustic agent. In addition, the aqueous formulation can include, based on the total weight of the aqueous formulation, 25% to 80%, 30% to 75%, 35% to 70%, or 40% to 65%, of the water. For example, when used for dip-coating, the fire resistant coating composition can be formed from, on a weight basis, 10% to 30% of the (1) metal silicate; 30% to 40% of the (2) metal oxide; 5% to 10% of the (3) water soluble caustic agent; and 20% to 50% of the (4) water, based on the total weight of the formulation. When used for an atomized spray application, the fire resistant coating composition can be formed from , on a weight basis, 15% to 35% of the (1) metal silicate; 5% to 30% of the (2) metal oxide; 10% to 25% of the (3) water soluble caustic agent; and 35% to 70% of the (4) water, based on a total weight of the formulation.

[0028] Although, the metal silicate and the metal oxide components are listed separately in the present disclosure, these components can be included in the aqueous formulation from a source that has both of these components together, such as, for example an aluminosilicate (e.g., a kaolin, etc.) and forming the aqueous formulation is not limited to using the metal silicate and the metal oxide as separate components. In certain embodiments, where the metal silicate and the metal oxide components are included from the same source, the combined metal silicate and the metal oxide component source are included is dissolved such that the aqueous formulation includes no more than 10 wt%, 8 wt%, 6 wt% 4 wt%, 2 wt% or less of solid particles in the formulation based on the total weight of the formulation and when the formulation is at a temperature of 25 °C. In these or other embodiments, where the metal silicate and the metal oxide components are included from the same source, the combined metal silicate and the metal oxide component source has a median diameter of less than 10 pm, e.g., having median diameter of no more than 9 pm, 8 pm, 7 pm, 5 pm, 3 pm, 2 pm, or no greater than 1 pm, when the composition or aqueous formulation is at a temperature of 25 °C. In certain embodiments, the metal silicate and the metal oxide components are not included from the same source

[0029] Useful metal silicates that can be used to form the compositions of the present disclosure include one or more of an alkali metal silicate, neosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, tectosilcates, Mullite, Kaolinite, Muscovite, etc. or combinations thereof. The metal silicate may be an amorphous metal silicate. Those skilled in the art will appreciate that an amorphous metal silicate will have an x-ray diffraction pattern that shows a broad, diffuse halo or hump-like feature instead of sharp, distinct peaks. For example, see Fig. 1. The alkali metal silicate can include a sodium silicate, e.g., sodium metasilicate, Na2 Si O2 ^x or (Na2O)_x (SiO2) , such as sodium metasilicate (Na2SiO3), sodium orthosilicate (Na4SiC>4), sodium pyrosilicate (Na6Si2O?), etc. These sodium silicate compounds are generally colorless transparent solids or white powders, and soluble in water in various concentrations. In some aspects of the present disclosure, the compositions and/or formulations comprise sodium metasilicate as the majority of the metal silicate, e.g. the metal silicate comprises at least 50 wt% sodium metasilicate such as at least 60 wt% of sodium metasilicate.

[0030] Metal oxides and metal hydroxides that can be used to form the compositions and aqueous formulations of the present disclosure include one or more of: aluminum trihydrate (ATH) (A1(OH)3), zinc oxide (ZnO), iron oxide, titanium dioxide (TiCh), copper oxide, zirconium oxide, manganese oxide, nickel oxide, silver oxide, vanadium oxide, bismuth oxide or combinations thereof. Further, it is understood that metal oxides in aqueous solutions convert to their equivalent hydroxide, and thus the use of metal hydroxide in the coating composition is equivalent to use of the metal oxide (e.g. ZnO is equivalent to Zn(OH)2). In some aspects of the present disclosure, the compositions and/or formulations are formed from aluminum trihydrate as the metal oxide in percent of the metal oxide of at least 20 wt % of the total metal oxide, e.g., 20 wt% to 100 wt%; 10 wt% to 50 wt%; or 75 wt% to 100 wt% of the total metal oxide.

[0031] The water soluble caustic agent of the composition and formulation is designed to facilitate dissolution of the alkali metal silicate and metal oxide in water and any other component that can react with the alkali metal silicate and metal oxide in water. Examples of water soluble caustic agents useful for the present disclosure include, without limitation or more of: an alkali metal hydroxide (such as NaOH, KOH), Na2O(SiO2), ammonium hydroxide, or a combination thereof. Sufficient amount of water soluble caustic agent is combined with the alkali metal silicate and metal oxide to form a composition and/or formulation with the desired level of solids and will increase the pH of the compositions and/or formulation to generate a pH of no less than 8, such as a pH no less than 8.5, 9, 9.5, 10, 10.5, 11, 12, 12.5, 13, 13.5, 14, 14.5, etc. Increasing the pH tends to increase the amount of alkali metal silicate and metal oxide dissolved in the formulation.

[0032] In some aspects, the coating compositions and/or formulations of the present disclosure has at least 95 wt. %, at least 96 wt. %, at least 97 wt. %, at least 98 wt. %, or at least 99 wt. % of the alkali silicate content as silicate ions in solution. In some aspects, the coating compositions and/or formulations of the present disclosure has 100% of the alkali silicate content as silicate ions in solution. This state can be determined, for example, when the solution can be passed through a 0.5 pm filter with no remaining visible particulate residue.

[0033] To facilitate spray application of the coating compositions of the present disclosure, the coating composition can have a viscosity ranging from about 25 cP to about 1,000 cP as determined by cup and bob viscosity measurement at a temperature of 85° F (29.4 °C), e.g., a viscosity ranging from about 20 cP to about 200 cP for very thin, uniform coating layers and about 140 cP to about 700 cP for thicker, rougher coating layers. Viscosity of the system measured by rotational viscometry (cup and bob viscosity measurement) is performed as per ASTM D2196, D2556, D7867.

[0034] The compositions and/or formulations of the present disclosure can be prepared by combining: (1) a metal silicate; (2) a metal oxide; (3) a water soluble caustic agent; and (4) water to form the composition. The (1) metal silicate and (2) the metal oxide can be from the same source material or separate source materials or a combination thereof. Coating compositions can further include combining other components that can react with the metal silicate and the metal oxide dissolved in, or substantially dissolved in, the formulation and combining other optional components.

[0035] Further the components can be in a kit prior to preparing the formulation in which one or more of the components are isolated from another component in the kit. The order of combining the components is not particularly limiting. Some components, however, typically take longer to dissolve in water and are thus more suited to combining as an initial step. For example, the metal silicate can be dissolved in water to form a metal silicate solution and then combined with the other components to form the coating composition. Alternatively, or in combinations, the water soluble caustic agent can be dissolved in water to form a caustic agent solution and then combined with the other components. Alternatively, or in combinations, the metal silicate and caustic agent can be dissolved in water as a metal silicate-caustic agent solution and then combined with the other components to form the coating composition. In some aspects, the initial (1) alkali metal silicate, (2) metal oxide, and/or (3) water soluble caustic agent initially can be in powder form such as finely divided powders having average powder diameters ranging from about 1 pm to about 40 pm. Such powder forms can facilitate dissolution of the components in a shorted period of time. (Typically when the powders have an average diameter of less than 1 micron, there can be viscosity increases associated with high surface areas to volume.) [0036] Further the kit can include the metal silicate solution isolated from the other components, or the caustic agent solution isolated from the other components, or the metal silicatecaustic agent solution isolated from the metal oxide and/or other components for forming the coating composition. The kit can further include instructions for preparing the coating composition and/or aqueous formulation according to the present disclosure and can provide instructions on how to apply the formulation to form a fire resistant coating on a substrate.

[0037] As explained earlier, in some implementations the prepared coating composition and/or formulation can be free of, or substantially free of, solid particles comprised of the metal silicate, metal oxide and water-soluble and even free of or substantially free of any solid particles. Such compositions and formulations can be prepared by substantially or completely dissolving the reactive components in water, including mixing and/or heating the composition until the desired dissolution of the component. In addition, or alternatively, preparing the compositions can include filtering the formed composition to remove solid particles and/or decanting the formed compositions from any solids. Filtering can be carried out by passing the formulation through a 0.5 pm to 50 pm filter or any range therebetween. Blending of the solution can be carried out by shear mixing, agitation, planetary centrifugal mixing, in-line static mixing, or other processes of combining liquid and solid components for dissolution or substantial dissolution. Particulate remnants may also be separated gravitationally or by centrifugal separation.

[0038] In certain implementations, the prepared coating composition and/or formulation can include one or more optional components, e.g., a catalyst, activator, pigment, rheology modifier, ceramic particle, fibers, surfactant, or any combination thereof. Certain of these components may or may not be soluble in the composition and may form solid components of the coating composition. However, in some implementations, the fire resistant coating composition or aqueous formulation is free of, or substantially free of, solid particles comprised of the metal silicate, metal oxide and water-soluble. In one aspect, an optionally included pigment can be selected from a pigment (e.g., iron oxide) that can react with and covalently bond to the metal silicate and/or metal oxide upon forming a coating from the composition. In some aspects, such a reactive pigment can be dissolved or substantially dissolved in the formulation to facilitate reaction with other reactive components.

[0039] In further aspects, a fire resistant coating can be formed from the fire resistant coating composition by applying the composition to a substrate and drying the applied composition on the substrate to cure the composition into a fire resistant coating on the substrate. As explained earlier the components of the coating composition are formed from (1) a metal silicate; (2) a metal oxide; (3) a water-soluble caustic agent; and (4) water. In some implementations, the coating composition can be free, or substantially free, of large solid particles such as solid particles of the metal silicate, metal oxide and water-soluble caustic agent. Limiting the solid particle content and/or size of solid particles in the aqueous formulation permits forming a fire resistant coating as one or more thin layers. The coating layers are believed formed by a reaction among the metal silicate, metal oxide and water-soluble caustic agent dissolved in the formulation to form a geopolymer matrix. In certain aspects, the aqueous formulation of the present disclosure advantageously can have all of the components that react to form the geopolymer matrix (e.g., metal silicate, metal oxide, water-soluble caustic agent, and other reactive components) dissolved or substantially dissolved in the formulation to allow formation of thin and uniform coating layers from such a formulation. Moreover, such coating compositions can be applied as a multi-layer coating with each layer composed of the same or a different coating composition.

[0040] In some implementations, a fire resistant coating can be formed by applying one or more coating compositions of the present disclosure to a substrate. The coating compositions can be applied to a surface of the substrate in a variety of ways including brushing, rolling, spray, dip coating, electrodeposition, etc. In one aspect, the coating composition is applied to the substrate by spraying the composition onto the substrate as an aerosol, e g., a suspension of fine liquid droplets in air or another gas. Aerosol sprays can be generated from aerosol spray dispensers, atomizers, etc.

[0041] In some implementations, one or more coating compositions can be applied to produce multiple layers of a coating with the same or different coating compositions. For example, one or more coating compositions can be applied to produce at least a first layer and a second layer. In such a way the first layer can have a composition derived from a first coating composition and the second layer can have a composition derived from a second coating composition. The first and second coating compositions and subsequent layers can be the same or be different such that the type and/or amounts of the components that comprise the coating composition can be different.

[0042] Concurrent with or after applying the one or more coating compositions to substrate surface, the composition dries or is dried. Drying the coating composition causes it to cure and bond to the surface of the substrate. Upon drying, the coating composition forms long-range, covalently bonded, non-crystalline (amorphous) networks from the reactive components of the composition such as a geopolymeric matrix material.

[0043] Drying can be carried out conveniently in air at ambient conditions. For example, the coating composition can be dried in air from a temperature range of about 5 °C to about 50 °C. Drying can also be carried out by heating at a temperature of from about 50 °C to about 500 °C in air or another gas, such as heating from 50 °C to about 500 °C, 50 °C to about 200 °C, 50 °C to about 150 °C. Exposing an applied coating composition of the present disclosure to heat can increase the hardness of the formed fire resistant coating as shown in an Example below.

[0044] Upon formation, the coating can include one or more layers formed from the fire resistant coating composition. In some aspects, each of the one or more layers can have a thickness in the range of 1 mil to 50 mils (25 pm to 1,270 pm) such as from 2-20 mils (51 pm to 508 pm), 2- 10 mils (51 pm to 254 pm), 2.5 - 6 mils, 3- 4 mils, for example. In some aspects, the coating may include 1 layer, at least 2 layers, at least 3 layers, at least 5 layers, at least 10 layers, at least 15 layers, or at least 20 layers. In these or other aspects, the coating may include from 1 layer to 50 layers, from 2 layer to 48 layers, from 3 layer to 45 layers, from 5 layer to 45 layers, from 10 layer to 40 layers, from 15 layer to 35 layers, or from 20 layer to 30 layers. In these or other aspects, each layer may be the same or different

[0045] Advantageously, the coating compositions of the present disclosure can be formed on a variety of substrates such as metals (e.g., steel, aluminum), cellulose, wood, concrete, thermoset and thermoplastic polymeric materials, construction and industrial materials, etc.

EXAMPLES

[0046] The following examples are intended to further illustrate certain aspects of the subject technology and are not limiting in nature. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific substances and procedures described herein.

[0047] Example 1

[0048] For this example, the coating composition was a solution of the components (and did not include solid particles). The solution was prepared by adding 200 g of commercially available 40% sodium silicate solution, 100 g ATH, 60 g zinc oxide, 5 g iron oxide (FesCL), 2 g sodium bicarbonate, 60 g 50% caustic soda solution, and 30 g water were added to a plastic container then stirred for 2 minutes with a 1 inch (2.5 cm) diameter blade shear mixer.

[0049] The coating composition was sprayed on the surface of a steel tube to form a uniform coating with no visible cracks. The steel tube with coating was then subjected to heat up to approximately 1,000 °F (538 °C), cooled and subject to stress by hitting the coating with a hammer while upon a metal support surface. The coating withstood the stress without chipping, cracking, or releasing from the steel tube.

[0050] Example 2

[0051] For this example, the coating composition was a solution of the components used for spray coating onto a flat thermoplastic panel substrate. The solution was prepared by adding 10 lbs. (4.54 kg) of commercially available 40% sodium silicate solution, 3.5 lbs. (1.59 kg) ATH, 3.0 lbs. (1.36 kg) zinc oxide, 3.0 lbs. (1.36 kg) wollastonite, 0.5 lbs. (0.23 kg) iron oxide (FesC ), 0.1 lbs (45.4 g) sodium bicarbonate, 2.5 lbs. (0.91 kg) 50% caustic soda solution, and 2.25 lbs. water were added to a 5 gallon (18.93 L) bucket and then stirred for 5 minutes with a 2 inch (5.1 cm) diameter blade shear mixer. The blend was allowed to sit for 48 hours, with re-mixing occurring occasionally to allow for maximum dissolution of components.

[0052] The coating composition was poured through a 125 mesh strainer into the reservoir of an airless paint sprayer. The sprayer was used to apply a thin coat (approximately 0.005”, or 0.13 mm) to the surface of the thermoplastic panel. The applied coating composition was allowed to dry for 30 minutes at ambient temperature and the practice was repeated until there were 3 coating layers on the substrate. The panel formed was tested for flame resistance by placing the sample flat on a ring stand 3 in. (7.6 cm) directly above a methane Bunsen burner for 30 seconds, removed from the flame for 30 seconds, and then burned again for 30 seconds. No melting or burning of the panel substrate was observed.

[0053] Example 3

[0054] It was observed that cure conditions for an applied coating composition of the present disclosure can affect the hardness of a coating made from the composition. In this example, a fire resistant coating composition was applied to the surface of panels under different application and cure conditions and Barcol hardness of the cured coatings were tested. Barcol hardness was determined with an INSIZE hardness tester on at least three different points of the sample and an average hardness was reported. Results from this testing are reported in Table 1 below. Table 1 : Barcol hardness of fire resistant geopolymer coating prepared with varying cure and postcure cycles.

[0055] The data show that heating an applied coating composition can increase the hardness of the formed coating.

[0056] Example 4

[0057] This example shows weight loss in forming a fire resistant coating from a coating composition of the present application. It is believed the coating compositions of the present disclosure form a geopolymer coating. The cure mechanism of geopolymers includes the consumption of OH ions from the caustic coating solution to form metal-ates i.e. silicates, aluminates, zincates, etc. as well as the evaporation of water as the metal -ate ions form into geopolymeric chains. A coating composition was mixed and samples were then drawn from the composition and measured for weight loss throughout the duration of curing the coating composition on the samples. The coating composition and the data gathered are displayed in Table 2 below. It is assumed that the entirety of the mass loss is water evaporation due to the fact it is the only material in the coating composition with an appreciable vapor pressure at the temperatures shown in the table. It is also believed that the materials being used will have some degree of water content (water of hydration) in their cured state, so a water loss of 100% is not anticipated. Table 2: Sample mass loss of a coating composition at different stages of the cure process.

[0058] Example 5

[0059] Fire barrier characteristics of a coating from a coating composition according to the present disclosure were determined in this example. Samples were submitted for third-party evaluation by way of the ASTM E-84-21a tunnel test. Total sample area for this test was 48 ft² (4.46 m²) with dimensions of 2 feet (0.61 m) wide by 24 feet (7.32 m) long. Two sets of samples were prepared: one using wood oriented strand board (OSB) and one with a pultruded fiberglass/iso-polyester resin composite panel. Sample preparation and test results are given in Table 3 below.

Table 3: ASTM E-84 fire tunnel test results of panels with a fire resistant coating according to the present disclosure.

[0060] It is understood that the E-84 flame spread index performance of OSB products is between 76 - 200 when un-coated, depending on wood and glue content in the product. However after application of 2 layers of the coating composition on the OSB, the flame spread index performance was successfully reduced such that the coated OSB could be classified as “Class A” which is desirable in many building and construction applications. The wide-spread use of OSB in housing and commercial construction could benefit greatly from fire resistant coating compositions of the present disclosure which can be readily applied to such substrates as shown by this example. The flame spread performance of the coated pultruded fiberglass/iso-polyester resin composite panel matched that of the coated OSB. However, the substrate itself produced smoke which exceeded the smoke index qualification to meet Class A. Nevertheless, the composite panel showed improved fire resistance with the particular coating formed in this example.

Example 5

[0061] For this example, the coating composition was a solution of the components that included 100 parts Sodium Silicate (40% solution in H2O), 50 parts ATH, 50 parts Zinc Oxide, and 20 parts Sodium Hydroxide (50% solution in H2O) For comparison a sample of sodium silicate was prepared. XRD analysis was performed on the Sodium silicate shown in Fig 1 and Example 5 shown in Fig. 2. As shown in Fig. 1, Sodium silicate forms an amorphous domain. XRD analysis of this produces two very broad peaks. Viewing example 5 in Fig. 2, introduction of a metal oxide, (i.e., aluminum hydroxide and zinc oxide) alters the sodium silicate such that peaks from the amorphous domain are significantly or even completely disrupted. These can be seen easily by comparing the broad peak of the amorphous sodium silicate in Fig. 1 at about the 20 range of 8.5 to 10.5to the same area on Fig. 2. The extent of the disruption is not just from dilution because the changes in the peak intensity are far greater than the relationship of the percent mass. This is further supported by EDX analysis of the system which shows incorporation of aluminum into the sodium silicate domains.

[0062] Only certain features and aspects of the present disclosure and examples of their versatility are shown and described in the present disclosure. It is to be understood that the technology disclosed herein is capable of use in various other combinations and environments and is capable of changes or modifications. Thus, for example, those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific substances, procedures and arrangements described herein. Such equivalents are considered to be within the scope of the invention and are covered by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A fire resistant coating composition comprising: an aqueous formulation prepared from:

(1) a metal silicate;

(2) a metal oxide;

(3) a water-soluble caustic agent; and

(4) water.

2. The fire resistant coating composition of claim 1, wherein the aqueous formulation excludes solid particles having an median diameter of greater than 10 pm when the aqueous formulation is at a temperature of 25 °C.

3. The fire resistant coating composition of claim 1, wherein the aqueous formulation is a solution of (1), (2) and (3) at 25 °C

4. The fire resistant coating composition of claim 1, wherein the ratio of metal silicate to metal oxide ranges from about 5:1 to 1 :5.

5. The fire resistant coating composition of claim 1, wherein at least 95 wt. % of the silicate content in the fire resistant coating composition are silicate ions in solution.

6. The fire resistant coating composition of claim 1, wherein the metal silicate comprises at least 50 wt% sodium metasilicate.

7. The fire resistant coating composition of claim 1, wherein the aqueous formulation includes, based on the total weight of the aqueous formulation, 10% to 45% of the (1) metal silicate; 5% to 65% of the (2) metal oxide; 5% to 25% of the (3) water soluble caustic agent.

8. The fire resistant coating composition of claim 1, wherein the aqueous formulation includes, based on the total weight of the aqueous formulation, 25% to 80% of the water.

9. The fire resistant coating composition of claim 1, wherein the aqueous formulation includes, based on the total weight of the aqueous formulation, 35% to 60% of the water.

10. The fire resistant coating composition of claim 1, wherein the aqueous formulation has a pH of no less than 9.

11. The fire resistant coating composition of any one of claims 1-10, wherein the aqueous composition has a viscosity ranging from about 25 cP to about 1,000 cP as measured by cup and bob viscosity measurement.

12. The fire resistant coating composition of any one of claims 1-10, wherein the metal silicate comprises an alkali metal silicate.

13. The fire resistant coating composition of any one of claims 1-10, wherein the metal silicate comprises an amorphous metal silicate.

14. The fire resistant coating composition of any one of claims 1-10, wherein the metal silicate comprises an amorphous sodium silicate.

15. The fire resistant coating composition of any one of claims 1-10, wherein the metal silicate comprises neosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, tectosilcates, or any combination thereof.

16. The fire resistant coating composition of any one of claims 1-10, wherein the metal silicate comprises Mullite, Kaolinite, Muscovite, or any combination thereof.

17. The fire resistant coating composition of any one of claims 1-10, wherein the metal oxide comprises one or more of aluminum trihydrate (ATH), zinc oxide (ZnO), iron oxide, titanium dioxide (TiO2), copper oxide, zirconium oxide, manganese oxide, nickel oxide, silver oxide, vanadium oxide, bismuth oxide, or any combination thereof.

18. The fire resistant coating composition of any one of claims 1 -10, wherein the water soluble caustic agent comprises one or more of an alkali metal hydroxide, Na₂O(SiO₂), or ammonium hydroxide.

19. The fire resistant coating composition of any one of claims 1-10, wherein the metal silicate comprises one or more of an alkali metal or alkali earth silicate; the metal oxide comprises one or more of aluminum trihydrate, or zinc oxide; and the water soluble caustic agent comprises one or more of NaOH, KOH, or Na₂O(SiO₂).

20. The fire resistant coating composition of any one of claims 1-10, further comprising a pigment that can covalently bond to the metal silicate and/or metal oxide upon forming a coating from the composition.

21. The fire resistant coating composition of claim 20, wherein the pigment comprises iron oxide.

22. The fire resistant coating composition of any one of claims 1-10, further comprising one or more catalysts or activators.

23. The fire resistant coating composition of any one of claims 1-10, further comprising one or more rheology modifiers.

24. The fire resistant coating composition of any one of claims 1-10, further comprising one or more fibers.

25. The fire resistant coating composition of any one of claims 1-10, further comprising one or more ceramic particles.

26. The fire resistant coating composition of any one of claims 1-10, further comprising one or more surfactants.

27. The fire resistant coating composition of any one of the previous claims, wherein the fire resistant coating composition is free of aluminosilicate mineral particles.

28. A coating formed from the fire resistant coating composition of any one of claims 1 to 27.

29. The coating of claim 28, wherein the coating is on a surface comprising a cellulose, polymer, metal, ceramic, cementitious based material, or a combination thereof.

30. The coating of claim 28, wherein the coating comprises one or more layers formed from one or more of the fire resistant coating composition, wherein each of the one or more layers has a thickness in the range of 1 mil to 50 mils (25 pm to 1,270 pm).

31. The coating of claim 28, wherein the coating comprises at least a first layer and a second layer, each of which is formed from one or more of the fire resistant coating composition, wherein the first layer has a composition that is different from the second layer.

32. A process for forming a fire resistant coating, the process comprising: applying the fire resistant coating composition of any one of claims 1 to 21 to a substrate; drying the applied composition on the substrate to cure the composition into a fire resistant coating on the substrate.

33. The process of claim 32, wherein applying the composition comprises spraying the composition onto the substrate as an aerosol.

34. The process of claim 32, wherein applying the composition comprises forming one or more layers of the fire resistant coating, wherein each layer has a thickness in the range of 1 - 50 mils (25 pm to 1,270 pm).

35. The process of claim 32, wherein applying the composition comprises spraying, rolling and/or rolling one or more of the compositions to form the coating.

36. The process of claim 32, wherein drying the applied composition comprises exposing the applied composition in air at a temperature of from about 5 °C to about 50 °C.

37. The process of claim 32, wherein drying the applied composition comprises exposing the applied composition to heat at a temperature of from about 50 °C to about 500 °C.

38. A kit comprising components of:

(1) a metal silicate;

(2) a metal oxide; and

(3) a water soluble caustic agent; wherein one or more of the components are isolated from another component.

39. The kit according to claim 38, wherein (1), (2) or (3) are in powder form.

40. The kit of claim 38, wherein the metal silicate is dissolved in water as a metal silicate solution and the kit comprises the metal silicate solution isolated from the other components.

41. The kit of claim 38, wherein the water soluble caustic agent is dissolved in water as a caustic agent solution and the kit comprises the caustic agent solution isolated from the other components.

42. The kit of claim 38, wherein the metal silicate and caustic agent are dissolved in water as a metal silicate-caustic agent solution and the kit comprises the metal silicate-caustic agent solution isolated from the metal oxide.

43. The kit of claim 38, further including one or more components of: a pigment; a catalyst; an activator; a rheology modifier; fibers; ceramic particles, or any combination thereof.

44. A process for forming a fire resistant coating composition, the process comprising: combining (1) a metal silicate; (2) a metal oxide; (3) a water soluble caustic agent; and (4) water to form the composition.

45. The process of claim 44, wherein (1) and (2) are in finely divided powder form.

46. The process of claim 44, wherein (1), (2) and (3) are combined and dissolved in the water to form an aqueous solution.