Non-intumescent passive fire protection coating

Abstract

The disclosure relates to non-intumescing or non-swelling coating compositions for use as fire-retardant coating on a variety of substrates. The coating compositions include at least one temperature-resistant polymeric matrix component, a fireproof filler material, and a pigment material. Methods and coated articles using the disclosed coating composition are also described.

Description

SW Ref. P01566-USP-WO (WO22145)NON-INTUMESCENT PASSIVE FIRE PROTECTION COATINGBACKGROUND

[0001] Passive fire protection (PFP) systems are widely used across industries and are critical for electric vehicle (EV) batteries. Materials are needed that can mitigate heat / electrical transfer, combustion and thermal runaway, upon the event of a catastrophic battery failure within the battery enclosure. These materials cannot prevent total failure of the enclosure; however, they are designed to mitigate and slow down heat transfer and enclosure failure for a period of time such that danger to occupants and those in the immediate vicinity can be minimized.[00021 Many state-of-the-art solutions currently rely on intumescent coatings - those that upon combustion and heat swell in thickness to form an inert passivation layer that prevents further combustion and thermal conductivity through the coated surface. These coatings have been demonstrated to have limited utility in EV battery enclosures as they (i) form electrically conductive char that can lead to short-circuiting, (ii) discharge char particulate that can block pressure release vents within the enclosure, and (ii) lack dynamic mechanical properties to absorb energy of discharged battery particles during failure.SW Ref. P01566-USP-WO (WO22145)

[0003] Alternative PFP strategies for EV battery enclosures include mica sheets, encapsulants, and phase change materials. These materials present particular trade-offs in cost, weight, manufacturability, application difficulty, flexibility to complex enclosure shapes, durability and corrosion protection.

[0004] Accordingly, there is a need for non-intumescent coatings that can mitigate these challenges while providing effective passive fire protection and thermal insulation for EV batteries.SUMMARY

[0005] Disclosed herein are compositions and methods for improved fire resistance or thermal insulation. The disclosed coating compositions may help stop or halt the spread of fire and / or reduce or mitigate the intensity of a fire, thermal runaway, or other events with uncontrollable high temperatures. The disclosed coating compositions are non-intumescent coatings and / or ceramifying coatings and may be part of a passive fire protection system and may be used in a wide variety of applications, including as protective coatings for the battery enclosures in electric vehicles. In some embodiments, the coating compositions described herein include at least one temperature-resistant polymeric matrix component, a fireproof filler component, and a pigment component.SW Ref. P01566-USP-WO (WO22145)

[0006] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0007] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. All combinations of the embodiments pertaining to the invention are specifically embraced by the present invention and are disclosed herein just as if each and every combination was individually and explicitly disclosed. In addition, all subcombinations of the various embodiments and elements thereof are also specifically embraced by the present invention and are disclosed herein just as if each and every such subcombination was individually and explicitly disclosed herein.Selected Definitions

[0008] As used herein, the term “fire retardant” describes an article or material that can slow or halt the spread of fire and / or mitigate or reduce the intensity of the fire, a thermal runaway, or other uncontrollable increases in temperature. With respect to theSW Ref. P01566-USP-WO (WO22145) compositions or methods described herein, the term “fireproof” and “fire-resistant” are used interchangeably with “fire-retardant.”

[0009] The term “passive fire protection” (PFP) refers to a system of components in a building that slows or stops the spread of smoke and fire without the need for activation. The fire-retardant compositions and methods described herein may be part of a passive fire protection system. In an aspect, the fire-retardant compositions and methods described herein may be a ceram ifying coating. As used herein, the term “ceramifying coating” refers to a material, preferably a liquid coating composition, that transforms into a ceramic-like layer when exposed to high temperatures, especially during a fire or thermal event.

[0010] Unless otherwise indicated, the term “polymer” includes both homopolymers and copolymers (i.e. , polymers of two or more different monomers). As used herein, the terms “polymer matrix” or “binder resin” are used interchangeably with “polymer.”[0011| The term “crosslinker” refers to a molecule capable of forming a covalent linkage between polymers or between two different regions of the same polymer.

[0012] The term “self-crosslinking,” when used in the context of a self-crosslinking polymer, refers to the capacity of a polymer to enter into a crosslinking reaction with itself and / or another molecule of the polymer, in the absence of an external crosslinker, to formSW Ref. P01566-USP-WO (WO22145) a covalent linkage therebetween. Typically, this crosslinking reaction occurs through reaction of complimentary reactive functional groups present on the self-crosslinking polymer itself or two separate molecules of the self-crosslinking polymer.[0013J The term “substantially free” of a particular component means that the compositions of the present invention contain less than 5 wt % of the component, based on the total weight of the composition. The term “essentially free” of a particular component means that the compositions of the present invention contain less than 1 wt % of the component, based on the total weight of the composition.

[0014] The term “on,” when used in the context of a coating applied on a surface or substrate, includes both coatings applied directly or indirectly to the surface or substrate. Thus, for example, a coating applied to a primer layer overlying a substrate constitutes a coating applied on the substrate.

[0015] The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.[0016| The term "and / or" or “and or” refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0017] The term "about," when referring to a measurable value such as length, width, diameter, radius, or an amount of a compound, dose, time, temperature, and theSW Ref. P01566-USP-WO (WO22145) like, is meant to encompass variations of 10%, 5%, 1 %, 0.5%, or even 0.1 % of the specified amount.

[0018] In the interest of brevity and conciseness, any ranges of values set forth in this specification contemplate all values within the range and are to be construed as support for claims reciting any sub-ranges having endpoints which are real number values within the specified range in question. By way of a hypothetical illustrative example, a disclosure in this specification of a range of from 1 to 5 shall be considered to support claims to any of the following ranges: 1 -5; 1-4; 1 -3; 1 -2; 2-5; 2-4; 2-3; 3-5; 3-4; and 4-5.

[0019] The term “substantially” is utilized herein to represent the inherent degree of uncertainty that can be attributed to any quantitative comparison, value, measurement, or other representation. The term “substantially” is also utilized herein to represent the degree by which a quantitative representation can vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0020] The terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Unless otherwise defined, all terms, including technical and scientific terms used in the description, have the same meaning as commonly understood by one of ordinary skill inSW Ref. P01566-USP-WO (WO22145) the art to which this disclosure belongs. In the event of conflicting terminology, the present specification is controlling.

[0021] The terms “preferred” and “preferably” refer to embodiments that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the present disclosure

[0022] As used throughout this description, and in the claims, a list of items joined by the term “at least one of” or “one or more of” can mean any combination of the listed terms. For example, the phrase “at least one of X, Y or Z” can mean X; Y; Z; X and Y; X and Z; Y and Z; or X, Y and Z.

[0023] All patents, patent applications and publications referred to herein are incorporated by reference in their entirety.DETAILED DESCRIPTION

[0024] Disclosed herein are fire-retardant coating compositions, coated articles, and a methods for improving the fire resistance of coated articles, including, but not limited to, electric vehicle (EV) batteries and the housing or enclosures for such devices.SW Ref. P01566-USP-WO (WO22145)

[0025] The coating compositions provided herein have the advantage of being non- intumescing or non-swelling, while exhibiting optimal fire-retardant and thermal insulative behavior, i.e. , the ability to mitigate or reduce heat transfer in the event of a fire, thermal runaway, or other event involving uncontrollable high temperature. This disclosure provides compositions and methods for use in or as a passive fire protection (PFP) system.

[0026] In at least one embodiment, the non-intumescing coating composition described herein is a ceram ifying coating. Such a coating is a specialized material designed to transform into a rigid ceramic-like layer when exposed to high temperatures such as during a fire or thermal runway event. The ability of the coating to transform into a ceramic-like layer enhances thermal protection and preserves the structural integrity of the underlying substrate.

[0027] Unlike intumescent coatings, which expand when heated, increasing their volume and forming a protective layer of char, ceram ifying coatings do not expand on exposure to heat but instead become a rigid, ceramic-like layer that provides an insulating barrier and can protect the surface of the substrate to which the coating is applied even when exposed to extreme temperatures.SW Ref. P01566-USP-WO (WO22145)

[0028] The PFP coating described herein maintains strong adhesion to the substrate and cohesion within itself on exposure to extreme temperature and thereby prevents delamination or cracking of the coating.

[0029] In one embodiment, the coating composition disclosed herein includes a polymeric matrix component or binder resin system. The polymer matrix component or binder resin system includes a polymer resin and optionally a crosslinking agent. Polymer resins in the binder resin system may be thermosetting and / or thermoplastic. In certain embodiments, a thermoplastic resin useful in the practice of the present invention may be amorphous, crystalline or semicrystalline. Example resins used in the polymer matrix component or binder resin system described herein include acyclic, cyclic, branched, linear, aliphatic, or aromatic resins. In an aspect, the binder system described herein may be waterborne, water-reducible, water-dispersible, or solvent-borne. Suitable polymeric resins include, without limitation, epoxy resin, (meth)acrylics, polyolefins, polyurethanes, polyamines, alkyds, polyesters, chlorinated resins, fluorinated resins, and the like. The choice of resin for a coating composition will be determined by the performance requirements of a given end use.

[0030] In an aspect, the polymeric matrix component is an epoxy resin, preferably a silicone epoxy. The term "silicone epoxy" (also referred to as “epoxy polysiloxane” or "epoxy-functional polysilicone") as used herein is intended to have its customary meaningSW Ref. P01566-USP-WO (WO22145) in the art, and includes a linear or branched polymeric constituent having one or more polysiloxane chains and having at least one epoxy functional group, including two or more epoxy groups, for example, diglycidyl functionality.[0031J Any suitable silicone epoxy, and mixtures or combinations thereof, may be used in the coating compositions described herein. Various commercially available silicone epoxy resin systems may be used as the polymer matrix component or binder resin system. Commercially available examples of silicone epoxy resin systems include, without limitation, resins sold under the trademarks SILIKOPOW EW, SILIKOPON ED, and others (Evonik). Other commercially available silicone epoxy resins that may be used in the compositions described herein include HP1250 (Wacker), ES-1002T and ES-1001T (Shin Etsu), and the like. Other types of pre-formulated silicone epoxy resin systems may be used, and silicone epoxy resins may be prepared by methods known in the art.

[0032] The polymer matrix component may be present in the coating composition described herein at a concentration that results in the desired coating performance. The amount may vary based on the specific silicone epoxy resins used. The amount may also vary based on the amounts of other components present in the coating composition, including on the amounts of resins in the composition as a whole. In some embodiments, the polymer matrix component is a silicone epoxy component present in the coating composition at a concentration of 2 wt% or higher, 5 wt% or higher, 10 wt% or higher, 15SW Ref. P01566-USP-WO (WO22145) wt% or higher, 20 wt% or higher, 25 wt% or higher, 30 wt% or higher, 35 wt% or higher, 40 wt% or higher, 45 wt% or higher, or 50 wt% or higher, based on the total weight of the composition. In some embodiments, the silicone epoxy component may be present in the coating composition at a concentration of 70 wt% or lower, 60 wt% or lower, 50 wt% or lower, 40 wt% or lower, 35 wt% or lower, 30 wt% or lower, 25 wt% or lower, 20 wt% or lower, 15 wt% or lower, 10 wt% or lower, or 5 wt% or lower, based on the total weight of the composition. In some embodiments, the silicone epoxy component may be present in the coating composition at a concentration of 2 wt% to 70 wt%, 5 wt% to 65 wt%, 10 wt% to 60 wt%, 15 wt% to 55 wt%, or 20 wt% to 50 wt%, based on the total weight of the composition.

[0033] In an embodiment, the polymer matrix component of the coating composition described herein further includes an additional resin component. In an aspect, the additional resin component is a silicone or polysiloxane resin. Any suitable silicone or polysiloxane resin, and mixtures or combinations thereof, may be used in the coating compositions described herein. The polysiloxane described herein may be alkyl and / or aryl substituted polysiloxane, copolymer, blend or mixture thereof, the alkyl substitution preferably selected from alkyl groups of 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, and most preferably methyl, propyl and the aryl substitution most preferably comprising phenyl groups. The compositions may include hydroxy functionalSW Ref. P01566-USP-WO (WO22145) organo-siloxanes, said organo-siloxane comprises units, including dimethyl, diphenyl, methyl-phenyl, phenylpropyl and their mixtures.

[0034] Various commercially available polysiloxane resins systems may be used as part of the polymer matrix component along with epoxy silane. Suitable examples of commercially available silicone resins include, without limitation, the DOWSIL line of products (Dow Corning); the SILRES line of products (Wacker), SR-355 (Momentive), and PDS-9931 (Gelest), or mixtures and combinations thereof. Other suitable silicone- based polymers are well known in the art, such as, for example, those described in Fujiyoshi et al., U.S. Pat. No. 4,107,148 and Woo et al., U.S. Pat. No. 4,879,344, both of which are incorporated herein by reference.

[0035] In some embodiments, the silicone resin in the polymer matrix component is present at a concentration of 0.5 wt% or higher, 1 wt% or higher, 2 wt% or higher, 5 wt% or higher, 10 wt% or higher, 15 wt% or higher, 20 wt% or higher, 25 wt% or higher, 30 wt% or higher, 35 wt% or higher, 40 wt% or higher, 45 wt% or higher, or 50 wt% or higher, based on the total weight of the coating composition. In some embodiments, the silicone resin may be present in the coating composition at a concentration of 50 wt% or lower, 40 wt% or lower, 35 wt% or lower, 30 wt% or lower, 25 wt% or lower, 20 wt% or lower, 15 wt% or lower, 10 wt% or lower, 5 wt% or lower, 2 wt% or lower, or 1 wt% or lower, based on the total weight of the composition. In some embodiments, the siliconeSW Ref. P01566-USP-WO (WO22145) resin may be present in the coating composition at a concentration of 0.5 wt% to 50 wt%, 1 wt% to 45 wt%, 2 wt% to 40 wt%, 5 wt% to 35 wt%, or 10 wt% to 30 wt%. In a preferred aspect, the silicone resin is present in the coating composition at a concentration of 1 wt% to 10 wt%, based on the total weight of the composition.

[0036] In an aspect, the polymer matrix component of the coating composition described herein is self-crosslinking, and in another aspect, the resin component is crosslinkable with an optional crosslinking agent reactive with the functional group(s) of the resin component.

[0037] In an embodiment, the coating composition described herein further includes a fireproof component, preferably a fireproof or fire-retardant filler component. Any suitable filler material may be used in the coating compositions described herein, and in a preferred aspect, the fire-retardant filler material contains phosphorous, chlorine, antimony, magnesium, boron, sulfur, nitrogen, carbon, and mixtures or combinations thereof. Suitable examples include, without limitation, antimony compounds, magnesium hydroxide, hydrated alumina compounds, borates, carbonates, bicarbonates, inorganic halides, phosphates, sulfates, organic halogens, organic phosphates, or any combination. In a preferred aspect, the fireproof filler material is an amine-functional phosphate material, such as, for example, commercially available fillers such as SACOFLAM 31103 (KrebsChem).SW Ref. P01566-USP-WO (WO22145)

[0038] In some embodiments, mineral fillers known to provide thermal insulation may also be used in the coating composition described herein, either alone or in combination with the fire-retardant filler component. These fillers may include glass microspheres, finely divided metal oxides, which may comprise at least one of pyrogenic silicas, arc silicas, low-alkali precipitated silicas, fumed silica, silicon dioxide aerogels, aluminum oxides, titania, calcia, magnesia, potassia, or combinations thereof. In a preferred aspect, the thermal insulation material is a purely mineral silicon dioxide material, such as, for example, commercially available filler material like TEGO Therm HPG 4000 (Evonik).[0039| In certain embodiments, the filler material may comprise endothermic fillers such as alumina trihydrate, magnesium carbonate, and other hydrated inorganic materials including cements, hydrated zinc borate, calcium sulfate (gypsum), magnesium ammonium phosphate, magnesium hydroxide, or any combination thereof. In further embodiments, the filler(s) may include lithium-containing minerals.[0040| The fireproof filler component of the coating composition described herein is present in an amount that is effective to provide fire retardation without being detrimental to other desirable performance attributes. In an aspect, the fireproof material is present in amount of from 2 wt% or higher, 5 wt% or higher, 10 wt% or higher, 15 wt% or higher, 20 wt% or higher, 25 wt% or higher, 30 wt% or higher, 35 wt% or higher, 40SW Ref. P01566-USP-WO (WO22145) wt% or higher, 45 wt% or higher, 50 wt% or higher, 60 wt% or higher, 70 wt% or higher, or 80 wt% or higher, based on the total weight of the composition. In some embodiments, the fireproof filler material may be present in the coating composition at a concentration of 80 wt% or lower, 70 wt% or lower, 60 wt% or lower, 50 wt% or lower, 40 wt% or lower, 35 wt% or lower, 30 wt% or lower, 25 wt% or lower, 20 wt% or lower, 15 wt% or lower, 10 wt% or lower, or 5 wt% or lower, based on the total weight of the composition. In a preferred aspect, the fireproof filler component is present in an amount of about 10 wt% to 80 wt%, based on the total weight of the composition.

[0041] In one embodiment, the coating composition described herein includes at least one pigment component. The pigment component may be an inorganic pigment, an organic pigment, or mixtures or combinations thereof. Various organic or inorganic pigments may be used in the present invention. Suitable examples of pigments include titanium dioxide (TiC ), carbon black, red iron oxide, yellow iron oxide, raw umber, phthalocyanine blue, phthalocyanine green, naphthol red, toluidine red, various organic yellows, various organic reds, carbazole violet, DPP reds, DPP yellows, and quinacridones.

[0042] In some embodiments, the pigment component is present at a concentration of 0.5 wt% or higher, 1 wt% or higher, 2 wt% or higher, 5 wt% or higher, 10 wt% or higher, 15 wt% or higher, 20 wt% or higher, 25 wt% or higher, 30 wt% or higher, 35 wt% or higher,SW Ref. P01566-USP-WO (WO22145)40 wt% or higher, 45 wt% or higher, or 50 wt% or higher, based on the total weight of the coating composition. In some embodiments, the pigment may be present in the coating composition at a concentration of 50 wt% or lower, 40 wt% or lower, 35 wt% or lower, 30 wt% or lower, 25 wt% or lower, 20 wt% or lower, 15 wt% or lower, 10 wt% or lower, 5 wt% or lower, 2 wt% or lower, or 1 wt% or lower, based on the total weight of the composition. In some embodiments, the pigment may be present in the coating composition at a concentration of 0.5 wt% to 50 wt%, 1 wt% to 45 wt%, 2 wt% to 40 wt%, 5 wt% to 35 wt%, or 10 wt% to 30 wt%. In a preferred aspect, the pigment is present in the coating composition at a concentration of 1 wt% to 10 wt%, based on the total weight of the composition.

[0043] In one embodiment, the coating composition described herein includes at least one adhesion promoter. By “adhesion promoter” is meant an additive that is included in a coating composition to form primary bonds with either the substrate surface or with any previously applied coating or pretreatment. As used herein, the one or more adhesion promoters function to improve dry adhesion, wet adhesion, or preferably, both, of the coating composition described herein to the substrate.

[0044] Suitable examples of adhesion promoters useful with the coating compositions described herein include, without limitation, silanes, silicones, catalytic metals, and the like. Of these, organosilane adhesion promoters or coupling agents areSW Ref. P01566-USP-WO (WO22145) preferred, including commercially available products such as SILQUEST A187 (Momentive), for example.

[0045] In an embodiment, if present in the coating composition, the adhesion promoter is present in an amount of preferably 0.001 to 10 wt%, more preferably 0.5 to 2.0 wt%, and even more preferably 0.1 to 1 .0 wt%, based on the total weight of the coating composition.

[0046] In one embodiment, the coating composition described herein includes at least one corrosion inhibitor. Suitable corrosion inhibitors useful in the compositions described herein include, for example, zinc borate, and the like. In an aspect, the corrosion inhibitor is present in an amount of about 1 to 30 wt%, preferably 5 to 25 wt%, based on the total weight of the composition.

[0047] Other additive compounds may optionally be included in the coating compositions described herein, depending on the substrate and application of interest. Examples of these include one or more solvents, defoaming aids, dispersing agents, grinding aids, wetting agents, surfactants, coalescing aids, processing aids, skid resistance agents, abrasion resistance agents, conductive agents, antistatic agents, coloring agents, anticorrosion aids, thickeners, sag resistant agents, plasticizers, antioxidants, ultraviolet stabilizers, biocides, fungicides, fillers, curing agents, or anySW Ref. P01566-USP-WO (WO22145) combination thereof. These can be used in accordance with conventional practices currently known or hereafter developed.

[0048] The coating compositions described herein are suitable for application on a variety of substrates to provide fire-retardant coatings, particularly metal or metal alloy substrates. Non-limiting examples of metal substrates that may benefit from having a coating composition of the invention applied on a surface thereof include hot-rolled steel, cold-rolled steel, hot-dip galvanized, electro-galvanized, aluminum, tin plate, various grades of stainless steel, and aluminum-zinc alloy coated sheet steel (e.g., GALVALUME sheet steel). The coating composition described herein may be applied as a primer coat directly to an applied over a pretreated substrate, over a primer, or over a pretreated and primed substrate surface.

[0049] The coating composition described herein may be applied in a thickness that provides full coverage of the substrate being coated. For example, the intumescent coating composition may be applied at a thickness of at least 400 pm (micrometer), at least 500 pm, at least 700 pm, at least 900 pm, at least 1000 pm, at least 1200 pm, at least 1400 pm, at least 1700 pm, or at least 1900 pm. The intumescent coating composition may be applied at a thickness of up to 2000 pm, up to 1800 pm, up to 1500 pm, up to 1300 pm, up to 1100 pm, up to 900 pm, up to 700 pm, up to 600 pm, or up to 500 pm. The intumescent coating composition may be applied at a thickness of 400 pmSW Ref. P01566-USP-WO (WO22145) to 2000 pm, 500 pm to 1800 pm, 600 pm to 1700 pm, 700 pm to 1600 pm, 800 pm to 1500 pm, 900 pm to 14000 pm, 1000 pm to 13000 pm, or 1100 pm to 12000 pm. In an aspect, the coating composition described herein is applied over a protective coating already on the substrate, including, for example, a pretreatment, a primer coating, and the like. In some embodiments, the substrate is pretreated and has an electrocoat primer coating applied thereon. In another embodiment, an electrocoat or other primer may not be necessary and the coating composition described herein can be applied directly to the pretreated substrate.

[0050] The present description provides a method to make a fire-retardant article. The method. The non-intumescent coating composition and / or ceramifying coating described herein may be applied to any surface or substrate to be protected against fire. Examples of substrates that the coating composition may be applied to include metals and metal alloys, e.g., steel, iron, aluminum, and the like; wood, composite, plastic, ceramic, and concrete. In particular, the coating may be useful for protecting one or more structures or components that make up the housing or enclosure of electric vehicle (EV) batteries. The coating composition described herein may be applied to the outside of an EV battery enclosure or on the inside of the inside of the EV battery enclosure, and in some embodiments, the coating maybe applied to both the inside and outside of the EV battery enclosure. The coating composition may be applied by any suitable method, suchSW Ref. P01566-USP-WO (WO22145) as spraying, brushing, or rolling. In a preferred aspect, the coating composition is spray applied by methods well known in the art. The coating composition may be applied using a single spray applicator or a dual spray applicator. In some embodiments, the coating composition is mixed prior to application and is applied by spraying using a single spray applicator.

[0051] Following application to the substrate, the coating composition described herein is cured to form a non-intumescent fire-retardant coating on the substrate. The time and temperature used to cure the applied coating composition will vary according to the intended use of the coating system. In a preferred aspect, the coating is spray applied to the substrate and cured at ambient temperature, typically 25°C, for seven (7) days.

[0052] The present description provides a fire-retardant coating system, such as a passive fire protection (PFP) system, for example. The coating system includes a substrate, and a non-intumescent coating composition applied on the substrate. The non- intumescent coating composition includes a temperature-resistant polymer matrix component, a fireproof filler component, and a pigment component. In at least some embodiments, the fire-retardant coating system described herein forms at least part of a PFP system. In an aspect, the fire-retardant coating described herein system is a ceram ifying coating system.SW Ref. P01566-USP-WO (WO22145)

[0053] PFP systems are critical for a wide variety of applications with a significant risk of fire, thermal runaway, or other events with uncontrollable high temperatures. PFPs are particularly important in EV battery technology, where PFPs can mitigate heat / electrical transfer, combustion, and thermal runaway, upon the event of a catastrophic battery failure within the battery enclosure.

[0054] The coating composition described herein combines the features of fire retardant, corrosion resistant, and mechanically robust coatings, into a non-intumescent or non-swelling formulation that is desirable for EV battery housing or enclosure applications. In this application, the protective material must be able to easily be applied (e.g. spray coating), while maintaining protective mechanisms that will not inhibit other safety features of the EV battery assembly, such as pressure relief vents, in contrast to intumescent coatings, where fire protection requires coating expansion and char formation that tends to block pressure relief vents in the EV battery housing. The material must also be more robust towards impact and corrosion than typical fire-resistant coatings that are applied on structural materials or building products, as the fire-retardant coatings described herein will be used in automotive / road applications.

[0055] The coating composition described herein is a non-intumescent / non- swelling coating composition with improved or comparable fire retardation and thermal insulative ability, (as demonstrated by flame test resistance (i.e., thermal resistance))SW Ref. P01566-USP-WO (WO22145) relative to existing intumescent coatings known in the art, such as SIKAGARD 834 (Graco), for example.

[0056] The coating composition described herein demonstrates several advantages over other fire-retardant coatings known in the art, particularly intumescent coatings: (a) reduced carbon charring and formation of conductive char; (b) reduced degradation on thermal exposure; (c) improved electrical resistivity; (d) low expansion, and material release, compared to intumescent materials; (e) increased thermal and fire protection at lower temperatures (500F), without material degradation (intumescing materials activate at 390-480F); (f) longer fire protection than intumescing coatings due to better chemical stability; and (g) optionally, may eliminate the need for electrocoat in providing corrosion protection.EXAMPLES

[0057] The invention is illustrated by the following examples. It is to be understood that the particular examples, materials, amounts, and procedures are to be interpreted broadly in accordance with the scope and spirit of the inventions as set forth herein. Unless otherwise indicated, all parts and percentages are by weight and all molecular weights are weight average molecular weight. Unless otherwise specified, all chemicals used are commercially available from, for example, Sigma-Aldrich, St. Louis, Missouri.SW Ref. P01566-USP-WO (WO22145)Example 1 : Preparation of Coating Compositions

[0058] A sample formulation, X1 , of the non-intumescing coating composition described herein was prepared by combining a silicone-based resin, fireproof filler materials, and other components in the amounts shown in Table 1 .Table 1. Preparation of Test Formulation X1Example 2: Thermal Insulation Performance

[0059] To test the thermal insulative performance of the sample formulation, X1 , a back panel test according to ASTM E84 (Standard Test Method for Surface BurningSW ef. P01566-USP-WO (WO22145)Characteristics of Building Materials) is conducted, where a coating is exposed to controlled fire conditions to evaluate its ability to resist flame spread and heat transfer, i.e. its thermal insulative performance. In this test, a test panel coated with the X1 sample formulation at a coating film thickness of about 630 to 670 pm is mounted vertically in a test chamber and a controlled flame is applied to the front surface of the panel until it reaches a temperature of about 850°C. The temperature increase of the coating over a 15-minute time period is measured using thermocouples placed on the back of the test panel. This provides a measure of heat transfer through the panel, and the steady maintenance of a relatively low temperature (i.e., no more than about 300°C) demonstrates effective thermal insulation on exposure to extremely high temperatures. Results of the test are shown in Table 2.SW Ref. P01566-USP-WO (WO22145)Table 2. Thermal Insulative Performance TestingExample 3. Torch and Grit Testing

[0060] To test the thermal insulative performance of the sample formulation, X1 , a torch and grit test according to UL2596 (Test Method for Thermal and Mechanical Performance of Battery Enclosure Materials) is conducted. In this test, a coated specimen or test panel is subjected to a simulated thermal runway, using a heat exposure sequenceSW ef. P01566-USP-WO (WO22145) of 15 seconds at 1200°C flame followed by 5 seconds of flame and grit blast to evaluate the number of cycles until the coating on the test panel fails or until 10 cycles are completed. A test panel coated with the X1 sample formulation at the film thickness shown in Table 3. The test panel is mounted vertically in a test chamber and a propane torch burner of specific diameter, typically 28.6mm, is used to direct a 3kW test flame at the coating. Surface temperature of the back panel, directly aligned with the torch, is measured by a thermocouple. A second thermocouple is placed a controlled distance away (typically 25mm) from the back panel to monitor the panel for complete burn through. Mechanical damage to the coating is qualitatively observed during the test by video. Results of the test are shown in Table 3.Table 3. Thermal Insulative Performance Testing (Torch and Grit)

[0061] Those skilled in the art will understand from the foregoing description that modifications and changes may be made in various embodiments of the presentSW Ref. P01566-USP-WO (WO22145) disclosure without departing from its true spirit of the invention. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense.

Claims

SW Ref. P01566-USP-WO (WO22145)CLAIMSWhat is claimed is:1 . A fire-retardant coating composition, the composition comprising: a temperature-resistant polymer matrix component; a fireproof component; and a pigment component, wherein the coating composition is non-intumescing.

2. A fire-retardant coating system, comprising a substrate; and a non-intumescent coating composition applied on the substrate, wherein the coating composition comprises a temperature-resistant polymer matrix component;SW Ref. P01566-USP-WO (WO22145) a fireproof filler component; and a pigment component.

3. A coated article, comprising: a substrate; and a non-intumescent coating composition applied on the substrate, wherein the coating composition comprises a temperature-resistant polymer matrix component; a fireproof filler component; and a pigment component.

4. A method to make a fire-retardant article, comprising: providing a substrate; applying a non-intumescent coating composition on the substrate, wherein the coating composition comprises a temperature-resistant polymer matrix component;SW Ref. P01566-USP-WO (WO22145) a fireproof filler component; and a pigment component; and curing the coating to form a non-intumescent fire-retardant coating on the substrate.

5. The composition, system, article, or method of any of the above claims, wherein the polymer matrix component comprises epoxy, silicone epoxy, silicone, (meth)acrylic resin, and mixtures or combinations thereof.

6. The composition, system, article, or method of any of the above claims, wherein the polymer matrix component comprises at least one silicone epoxy present in an amount of about 20 wt% to 50 wt%, based on the total weight of the composition.

7. The composition system, article, or method of any of the above claims, wherein the polymer matrix component comprises at least one silicone resin present in an amount of about 1 wt% to 10 wt%, based on the total weight of the composition.SW Ref. P01566-USP-WO (WO22145)8. The composition, system, article, or method of any of the above claims, wherein the fireproof component is a filler material that phosphorous, chlorine, nitrogen, carbon and mixtures or combinations thereof.

9. The composition, system, article, or method of any of the above claims, where the fireproof component is present in an amount of about 10 wt% to 80 wt%, based on the total weight of the composition.

10. The composition, system, article, or method of any of the above claims, wherein the pigment component is selected from an organic pigment, an inorganic pigment, or mixtures or combinations thereof.

11. The composition, system, article, or method of any of the above claims, wherein the pigment component is present in an amount of about 1 wt% to 20 wt%, based on the total weight of the composition.

12. The composition, system, article, or method of any of the above claims, further comprising an adhesion promoter.

13. The composition, system, article, or method of any of the above claims, further comprising an adhesion promoter present in the amount of about 0.1 wt% to 1 .0 wt%, based on the total weight of the composition.SW Ref. P01566-USP-WO (WO22145)14. The composition, system, article, or method of any of the above claims, further comprising a corrosion inhibitor.

15. The composition, system, article, or method of any of the above claims, further comprising a corrosion inhibitor present in an amount of about 5 wt% to 25 wt%, based on the total weight of the composition.

16. The composition, system, article, or method of any of the above claims, further comprising one or more additives selected from dispersants, rheology modifiers, levelers, defoamers, insulating additives, and mixtures or combinations thereof.

17. The system, article, or method of any of the above claims, wherein the substrate is pretreated metal.

18. The system, article, or method of any of the above claims, wherein the substrate is a composite material.

19. The system, article, or method of any of the above claims, wherein the substrate forms at least part of an external surface of an electric vehicle battery housing.SW Ref. P01566-USP-WO (WO22145)20. The system, article, or method of any of the above claims, wherein the substrate forms at least part of an internal surface of an electric vehicle battery housing.

21. The system, article, or method of any of the above claims, wherein the coating is part of a passive fire protection system.

22. The system, article, or method of any of the above claims, wherein the coating is applied over an electrocoat primer applied to the substrate.

23. The system, article, or method of any of the above claims, wherein the coating is applied over a pretreated metal or composite surface of an electric vehicle battery housing.

24. The composition, system, article, or method of any of the above claims, wherein the coating demonstrates reduced carbon charring and formation of conductive char relative to an intumescent coating composition .

25. The composition, system, article, or method of any of the above claims, wherein the coating demonstrates improved electrical resistivity relative to an intumescent coating composition.SW Ref. P01566-USP-WO (WO22145)26. The composition, system, article, or method of any of the above claims, wherein the coating demonstrates low expansion and reduced material release relative to an intumescent coating composition.

27. The composition, system, article, or method of any of the above claims, wherein the coating demonstrates increased thermal protection at a lower temperature without material degradation relative to an intumescent coating composition.

28. The composition, system, article, or method of any of the above claims, wherein the coating demonstrates equal or improved thermal insulation relative to an intumescent coating composition.

29. The composition, system, article, or method of any of the above claims, wherein the non-intumescent coating composition is a ceramifying coating.

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