Anti-fog and Anti-frost optical coatings and methods of making and using same

Abstract

Transparent and mechanically robust anti-fog and / or anti-frost coatings are disclosed, along with systems and methods for producing same. The coatings comprise polyvinyl alcohol, polyacrylic acid, and at least one organic or inorganic chemical crosslinking agent in a process and / or formulation that may provide mediated crosslinking. The coatings may be produced in a substantially VOC-free manner.

Description

ANTI-FOG AND ANTI-FROST OPTICAL COATINGS AND METHODS OF MAKING AND USING SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US Provisional Application No. 63 / 604,581, filed November 30, 2023. The entire contents of the above -referenced patent application(s) are hereby expressly incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not Applicable.TECHNICAL FIELD

[0003] The present disclosure is related to the technical field of optical coatings. More specifically, the present disclosure is related to the field of fog and frost mitigation coatings for optical components.BACKGROUND

[0004] Fogging and frosting occur when water vapor condenses on a solid surface to form water droplets or ice particles. This phenomenon is detrimental to the performance and function of optical materials due to reduced optical clarity and reduced light transmission, making mitigation of these effects important to a variety of fields, including medical instruments, eye-glasses, photography equipment, face shields, goggles, telescopic or laparoscopic devices, food displays, mirrors, automotive surfaces, sensors, shower doors, etc.

[0005] A common approach is to increase the surface energy of the optical component, creating a more hydrophilic (water-loving) surface with correspondingly lower water contact angle. The result being a surface where water drops spread and coalesce to form a continuous film of water that allows incident light to pass through without scattering.

[0006] Hydrophilic surfaces; however, in many cases fail to prevent the formation of frost when exposed to temperatures below the freezing point of water. The coalesced film of water quickly freezes forming a thin sheet of ice, or frost, that results in light scattering.

[0007] Optical surfaces exist for the purpose of being highly transmissive and nonscattering to preserve the fidelity of the image projected or reflected. Fogging occurs when the surface temperature of a material is lower than the dew point of water vapor, resulting in condensation of the water vapor on the material. Water condensation, or fogging, of the surface is harmful to optical systems primarily due to poor optical clarity and reduced light transmittance. This may occur when, for example, water droplets present on the surface exist as discrete droplets larger than 190 nm, or half the shortest wavelength of visible light (380 nm) which results in optical light scattering, reducing the optical intensity and / or image fidelity.

[0008] There are various known processes used to make anti-fog / anti-frost coatings. However, those processes suffer from various drawbacks. For example, some processes produce coatings using hazardous organic solvents and produce significant hazardous waste in production environments due to the solvents required for cleaning processes. These coatings are typically several micrometers thick, and generally swell because of water absorption, causing them to soften and become less mechanically resilient. Other examples, such as lamination processes have rejection rates that have been reported as high as 50%.

[0009] The production of a robust, mechanically resilient coating with permanent antifog and anti-frost performance with high-throughput, VOC-free production methods remains a challenge in the industry.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more implementations described herein and, together with the description, explain these implementations. The drawings are not intended to be drawn to scale, and certain features and certain views of the figures may be shown exaggerated, to scale or in schematic in the interest of clarity and conciseness. Not every component may be labeled in every drawing. Like reference numerals in the figures may represent and refer to the same or similar element or function.

[0011] FIG. 1 contains a flow diagram showing a process for producing an anti-fog and / or anti-frost coating in accordance with the present disclosure.

[0012] FIG. 2 is a block diagram showing two examples of an anti-fog and / or anti-frost coating(s) disposed on a substrate in accordance with the present disclosure.

[0013] FIG. 3 shows an example of a crosslinking mechanism for inorganic crosslinking according to the present disclosure. Note that: each crosslinking agent has multiple reactive sites and can react one or more time with a multitude of PVA molecules; and the relative molecular weights of PVA and PAA (designated by "n", number of repeat units) are independent, and can individually be represented by any range disclosed in the embodiment for each component.

[0014] FIG. 4 contains graphs showing an illustrative measurement of light transmittance of coated and uncoated glass substrates as a function of wavelength.

[0015] FIG. 5 contains a graph illustrating Taber abrasion.

[0016] FIG. 6 graphically illustrates a basic set up utilized for Time To Fog (TTF) testing.DETAILED DESCRIPTION

[0017] Before explaining at least one embodiment of the present disclosure in detail by way of exemplary language and results, it is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of the components set forth in the following description. The present disclosure is capable of other embodiments or of being practiced or carried out in various ways. As such, the language used herein is intended to be given the broadest possible scope and meaning; and the embodiments are meant to be exemplary - not exhaustive. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0018] Unless otherwise defined herein, scientific and technical terms used in connection with the present disclosure 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. The prior art techniques and procedures are generally performed according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout the present specification.

[0019] All patents, published patent applications, and non-patent publications mentioned in the specification are indicative of the level of skill of those skilled in the art to which the present disclosure pertains. All patents, published patent applications, and non-patent publications referenced in any portion of this application are herein expressly incorporatedby reference in their entirety to the same extent as if each individual patent or publication was specifically and individually indicated to be incorporated by reference.

[0020] All of the articles, systems, kits, and / or methods disclosed herein can be made and executed without undue experimentation in light of the present disclosure. While the articles, systems, kits, and / or methods have been described in terms of particular embodiments, it will be apparent to those of skill in the art that variations may be applied to the articles, systems, kits, and / or methods and in the steps or in the sequence of steps of the methods described herein without departing from the concept, spirit, and scope of the present disclosure. All such similar substitutions and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the present disclosure as defined by the appended claims.

[0021] As utilized in accordance with the present disclosure, the following terms, unless otherwise indicated, shall be understood to have the following meanings:

[0022] The use of the term "a" or "an" when used in conjunction with the term "comprising" in the claims and / or the specification may mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more than one." As such, the terms "a," "an," and "the" include plural referents unless the context clearly indicates otherwise. Thus, for example, reference to "a compound" may refer to one or more compounds, two or more compounds, three or more compounds, four or more compounds, or greater numbers of compounds. The term "plurality" refers to "two or more."

[0023] The use of the term "at least one" will be understood to include one as well as any quantity more than one, including but not limited to, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" may extend up to 100 or 1000 or more, depending on the term to which it is attached; in addition, the quantities of 100 / 1000 are not to be considered limiting, as higher limits may also produce satisfactory results. In addition, the use of the term "at least one of X, Y, and Z" will be understood to include X alone, Y alone, and Z alone, as well as any combination of X, Y, and Z.

[0024] The use of ordinal number terminology (i.e., "first," "second," "third," "fourth," etc.) is solely for the purpose of differentiating between two or more items and, unless explicitly stated otherwise, is not meant to imply any sequence or order or importance to one item over another or any order of addition, for example.

[0025] The use of the term "or" in the claims is used to mean an inclusive "and / or" unlessexplicitly indicated to refer to alternatives only or unless the alternatives are mutually exclusive. For example, a condition "A or B" is satisfied by any of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0026] As used herein, any reference to "one embodiment," "an embodiment," "some embodiments," "one example," "for example," or "an example" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearance of the phrase "in some embodiments" or "one example" in various places in the specification is not necessarily all referring to the same embodiment, for example. Further, all references to one or more embodiments or examples are to be construed as non-limiting to the claims.

[0027] Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error for a composition / apparatus / device, the method being employed to determine the value, or the variation that exists among the study subjects. For example, but not by way of limitation, when the term "about" is utilized, the designated value may vary by plus or minus twenty percent, or fifteen percent, or twelve percent, or eleven percent, or ten percent, or nine percent, or eight percent, or seven percent, or six percent, or five percent, or four percent, or three percent, or two percent, or one percent from the specified value, as such variations are appropriate to perform the disclosed methods and as understood by persons having ordinary skill in the art.

[0028] As used in this specification and claim(s), the words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include"), or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherently present therein.

[0029] The term "or combinations thereof" as used herein refers to all permutations and combinations of the listed items preceding the term. For example, "A, B, C, or combinations thereof" is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuingwith this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AAB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

[0030] As used herein, the term "substantially" means that the subsequently described event or circumstance completely occurs or that the subsequently described event or circumstance occurs to a great extent or degree. For example (but not by way of limitation), when associated with a particular event or circumstance, the term "substantially" means that the subsequently described event or circumstance occurs at least 80% of the time, or at least 85% of the time, or at least 90% of the time, or at least 95% of the time. The term "substantially adjacent" may mean that two items are 100% adjacent to one another, or that the two items are within close proximity to one another but not 100% adjacent to one another, or that a portion of one of the two items is not 100% adjacent to the other item but is within close proximity to the other item.

[0031] As used herein, the phrases "associated with," "coupled to," and "connected to" include both direct association / coupling / connection of two elements to one another as well as indirect association / coupling / connection of two elements to one another. When two elements are indirectly associated / coupled / connected to one another, one or more intervening elements may be present therebetween.

[0032] The term "water soluble polymer," as used herein, means organic substances that dissolve, disperse, and / or swell in water without the need for cosolvent or emulsification. Examples include polyvinyl alcohol, poly acrylic acid, or polyacrylamide.

[0033] The term "inorganic oxide," as used herein, means a compound that contains metal and can be converted to metal oxide by, for example by hydrolysis or condensation reaction of an organic metal alkoxide, or may be obtained in the form of stabilized nanoparticle in water or other solvent.

[0034] The term "crosslinking agent," as used herein, means a compound possessing two or more functional groups that are reactive, for example, secondary alcohol groups like those exemplified by PVA. Non-limiting examples of crosslinking agents include di-, tri-, or poly acrylic acids or aldehydes, such as (but not limited to) glyoxal, glutaraldehyde, formaldehyde, and the like; metal and metalloid alkoxides, such as (but not limited to) silicon alkoxides (such as, but not limited to, di-, tri-, or tetra-ethyl orthosilicates), silanes (such as, but not limitedto, PEG silanes and Dipodal silanes), titanium alkoxides, zirconium alkoxides, aluminum alkoxides, boric acid, and the like; other class moieties possessing varied organic constituents, for example tetra-methyl orthosilicate or functionalized alkoxides, such as (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS) and tetraethoxysilane (TEOS); di- or poly carboxylic acids, such as but not limited to maleic acid, or citric acid; polyisocyanates; polyurethanes; epichlorohydrins (polycup); and the like; as well as any combinations thereof. One non-limiting example of a PEG silane comprises triethoxysilylpropoxy(polyethyleneoxy)dodecandoate, while one non-limiting example of a Dipodal silane comprises 1,2-Bis(trimethoxysilyl)decane.

[0035] The terms "substantially volatile organic compound-free" and "substantially VOC- free," as used herein, refer to a solution that is substantially free from alcohol or organic solvents. More specifically, a solution that includes only miniscule amounts of volatile organics, particularly alcohols (e.g., produced due to hydrolysis of the alkoxides), "substantially VOC-free" means having volatile organic amounts such as (but not limited to) less than about 10 wt%, less than about 5 wt%, less than about 2 wt%, or less than about 1 wt%.

[0036] The terms "water-based," "aqueous," and "water-borne" are herein used as synonyms with the common definition of a solution in which water is the primary solvent, which is defined as greater than 50% of the solvents present in the solution.

[0037] The term "ambient" as used herein refers to a temperature typically in a range of from about 16°C to about 26°C at 1 atm pressure.

[0038] Turning now to the inventive concepts, certain non-limiting embodiments of the present disclosure relate to coating compositions for fog and frost mitigation for optical components, as well as methods of making and using same. While not wishing to be bound by any theory, these coatings may not overcome the physics of vapor condensation on the solid optical surface, but may seek to mitigate the detrimental effects of droplet / crystal formation leading to optical scattering, obscuring substrate, and decreased optical clarity and / or reduced transmission of light.

[0039] Certain non-limiting embodiments of the present disclosure are directed to a process for making an anti-fog / anti-frost coating (AFC) composition comprising the steps of preparing an aqueous dispersion of water-soluble polymers and non-inert inorganic oxide filler and / or at least one chemical crosslinking agent (CLA), whereby chemical reactionbetween the components render the dried and cured coating mechanically durable and robust toward ambient environmental conditions.

[0040] Certain non-limiting embodiments of the present disclosure also relate to a coating composition as obtained with said process, and to a process of applying AFC to a substrate using such compositions, and to the resulting coated substrate or component.

[0041] Certain non-limiting embodiments of the present disclosure relate to a process for making an anti-fog / anti-frost coating (AFC) composition comprising the steps of preparing an aqueous dispersion of water-soluble polymers and non-inert inorganic oxide filler and / or at least one chemical crosslinking agent (CLA), whereby chemical reaction between the components renders the dried and cured coating mechanically durable, insoluble, and robust toward ambient environmental conditions.

[0042] Certain non-limiting embodiments of the present disclosure are related to a system for producing an anti-fog and / or anti-frost optically transparent coating. The system includes (1) an aqueous solution comprising a water-soluble polyvinyl alcohol (PVA) and optionally a water-soluble polyacrylic acid (PAA); and (2) at least one of: (a) an aqueous solution comprising at least one water-soluble, organic or inorganic chemical crosslinking agent, and / or (b) a hydrolyzable metal-alkoxide. The metal-alkoxides are not water-borne or water-soluble but undergo a hydrolysis reaction that renders them miscible in water.

[0043] In certain particular (but non-limiting) embodiments, the system may further include instructions for one or more steps of: combining (1) and (2) to form a mixture, applying the mixture to a substrate, and / or curing the mixture applied to the substrate to produce the anti-fog and / or anti-frost coating on the substrate.

[0044] In certain particular (but non-limiting) embodiments, the solution of (1) may further contain at least one additional component. One non-limiting example of an additional component that may be present includes at least one surfactant, such as, but not limited to, anionic, non-ionic, fluorinated, or surfactants based on polydimethylsiloxane or sodium or ammonium polyacrylates; and in a particular (but not limiting) embodiment, surfactants based on fluorinated ethoxylates. One non-limiting embodiment of a surfactant that may be utilized in accordance with the present disclosure is polyoxyethylene ether nonionic fluorosurfactant (such as, but not limited to, CAPSTONE® FS-30, Dupont Chemicals Company, Wilmington, DE). Non-limiting examples of anionic surfactants that may be utilized in accordance with the present disclosure include sodium dodecylsulfate (SDS), sodiumdodecyl benzene sulfate (SDBS), ammonium lauryl sulfate, and the like. Non-limiting examples of non-ionic surfactants that can be utilized in accordance with the present disclosure include Decaethyleneglycol monodecyl ether (DGDME), poloxamers, Tweens, and the like.

[0045] Other non-limiting examples of additional component(s) that may be added include: (1) at least one filler material for creating a composite structure and to provide greater structural rigidity and resistance to abrasion (such as, but not limited to, fumed silica, silica nanoparticles, organically modified silica nanoparticles, and the like, as well as any combinations thereof); (2) at least one slip additive to reduce friction at interface between the coating and another material (such as, but not limited to, at least one release agent for injection molded plastics, etc.); (3) at least one cellulosic, saccharide, biopolymer, and the like, as well as any combinations thereof (e.g., chitosan, chitin, sodium a Iginate / a Igin ic acid, and the like, as well as combinations thereof); (4) at least one pH modifier (such as, but not limited to, acetic acid, hydrochloric acid, citric acid, or other di- or poly carboxylic acids, and the like; note that sodium alginate is also acidic and can function as a pH modifier); and the like, as well as any combinations thereof. Non-limiting examples of silica nanoparticles that may be utilized in accordance with the present disclosure include ST-O, CT20DH, CC301, other acidic aqueous particles or epoxy functionalized particles, and the like.

[0046] In certain particular (but non-limiting) embodiments, the systems of the present disclosure are substantially free of volatile organic compounds.

[0047] Certain non-limiting embodiments of the present disclosure are related to an antifog and / or anti-frost coating composition, wherein the coating composition comprises polyvinyl alcohol; at least one organic or inorganic chemical crosslinking agent; and optionally polyacrylic acid. In addition, the coating composition may be substantially optically transparent and / or have a transmission loss of less than about 1% at 550 nm wavelength. In addition, in certain particular (but non-limiting) embodiments, the coating composition is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

[0048] In certain particular (but non-limiting) embodiments, any of the coatings disclosed or otherwise contemplated herein may have a pencil hardness of at least about 3H. In addition, in certain particular (but non-limiting) embodiments, the coating is not degraded after 10 minutes water immersion test.

[0049] In certain particular (but non-limiting) embodiments, the coating composition may contain at least one additional component. One non-limiting example of an additional component that may be present includes at least one surfactant, such as, but not limited to, fluorinated ethoxylates. In a particular (but non-limiting) embodiment, the coating composition contains polyoxyethylene ether nonionic fluorosurfactant (such as, but not limited to, CAPSTONE® FS-30, Dupont Chemicals Company, Wilmington, DE).

[0050] Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer manufactured by turning ethylene into vinyl acetate through chemical reaction with oxygen and acetic acid, then polymerized and dissolved in alcohol to become the polymer polyvinyl acetate. Treating this polymer with an alkaline catalyst such as sodium hydroxide results in the hydrolysis of the polyvinyl acetate, converting some of the acetyl groups to alcohol groups, without disruption of the long-chain carbon polymer backbone. The resulting PVA may have a range of molecular weight (commonly from 25,000 to 500,000+) and level of hydrolysis (commonly from 55 to 99+% hydrolyzed). The molecular weight effects the solubility and viscosities, while the level of hydrolysis influences solubility and reactivity. For example, PVA with a high degree of hydrolysis will be highly soluble in water and virtually insoluble in practically any organic solvent. Further, hydroxyl groups are the primary reactive component of the PVA when used as a binder in a variety of systems, such as protective films, adhesives, and the like.

[0051] In these systems, PVA is "crosslinked" commonly using chemicals with multiple sites reactive toward the secondary alcohols of PVA to bind one PVA-bound hydroxyl to another.

[0052] For example (but not by way of limitation), a high degree of crosslinking results in a mechanically robust film highly resistant to physical and chemical abrasion while a noncrosslinked film results in little to no water resistance. To achieve a mechanically robust and hydrophilic / hygroscopic / swellable PVA film, the crosslinking must be mediated to achieve the necessary trade-offs between the extremes of crosslinking.

[0053] Crosslinking of PVA may be accomplished using a variety of multifunctional chemical species or molecules that link together various PVA moieties by reaction with secondary alcohols along the PVA polymer chain. Non-limiting examples of crosslinking agents that may be utilized in accordance with the present disclosure include di-, tri-, or poly acrylic acids or aldehydes, such as (but not limited to) glyoxal, glutaraldehyde, formaldehyde, and the like; metal and metalloid alkoxides, such as (but not limited to) silicon alkoxides (suchas, but not limited to, di-, tri-, or tetra-ethyl orthosilicates), titanium alkoxides (such as, but not limited to, titanium isopropoxide and titanium ethoxide), zirconium alkoxides (such as, but not limited to, zirconium ethoxide), aluminum alkoxides (such as, but not limited to, aluminum isopropoxide and aluminum sec butoxide), vanadium alkoxides (such as, but not limited to, vanadyl isopropoxide), niobium alkoxides (such as, but not limited to, niobium ethoxide), tantalum alkoxides (such as, but not limited to, tantalum ethoxide), silanes (such as, but not limited to, PEG silanes and Dipodal silanes, and in particular (but not by way of limitation, triethoxysilylpropoxy(polyethyleneoxy)dodecandoate and 1,2-Bis(trimethoxysilyl) decane, respectively), boric acid, and the like; other class moieties possessing varied organic constituents, for example potassium tert-butoxide, tetraethyl orthosilicate, tetra-methyl orthosilicate, or (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS) and tetraethoxysilane (TEOS); di- or poly carboxylic acids, such as but not limited to maleic acid, citric acid, or poly acrylic acid; polyisocyanates; polyurethanes; epichlorohydrins (polycup); and the like; nanoparticle-based forms of any of the above (e.g., metal nanoparticles, metalloid nanoparticles, metal oxide nanoparticles, metalloid oxide nanoparticles, etc.); as well as any combinations thereof.

[0054] Disclosed herein includes the use of a crosslinking strategy for water-based PVA coatings utilizing monomeric, polymeric, or nanoparticle based inorganic metal oxides such as silicon oxides, titanium oxides, aluminum oxides, tin oxides, etc. In this case, the PVA hydroxyls react with the surface hydroxyls on the metal oxides to form a chemical bond through condensation reactions. Alternatively, disclose herein includes the use of a crosslinking strategy utilizing metal alkoxides, whereby the metal alkoxide is first hydrolyzed, then facilitates crosslinking of PVA via condensation reaction with the polymer. Lastly, disclosed herein includes the use of a crosslinking strategy utilizing di- or higher poly carboxyl moieties to facilitate crosslinking via esterification reaction with PVA hydroxyls.

[0055] The polyvinyl alcohol utilized in accordance with the present disclosure may possess any molecular weight that allows the polyvinyl alcohol to function in accordance with the present disclosure. In addition, the polyvinyl alcohol may be a "low molecular weight" or a "high molecular weight" polyvinyl alcohol. Non-limiting examples of PVA molecular weights that may be utilized in accordance with the present disclosure include about 5,000; about 10,000; about 15,000; about 20,000; about 25,000; about 30,000; about 35,000; about 40,000; about 45,000; about 50,000; about 55,000; about 60,000; about 65,000; about70,000; about 75,000; about 80,000; about 85,000; about 90,000; about 95,000; about 100,000; about 125,000; about 150,000; about 175,000; about 200,000; about 225,000; about 250,000; about 275,000; about 300,000; about 325,000; about 350,000; about 375,000; about 400,000; about 425,000; about 450,000; about 475,000; about 500,000; and the like, as well as a range formed of two of any of the above values (e.g., a range of from about 5,000 to about 500,000; a range of from about 5,000 to about 100,000; a range of from about 100,000 to about 500,000; a range of from about 5,000 to about 50,000; a range of from about 10,000 to about 30,000; etc.).

[0056] The polyvinyl alcohol utilized in accordance with the present disclosure may possess any degree of hydrolysis that allows the polyvinyl alcohol to function in accordance with the present disclosure. Non-limiting examples of degrees of hydrolysis that may be utilized in accordance with the present disclosure include about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 95%, about 99%, about 100%, and the like, as well as a range formed from two of the above values (e.g., a range of from about 55% to about 100%, a range of from about 70% to about 90%, etc.).

[0057] The at least one crosslinking agent may be present in the coating at any concentration that allows for crosslinking of the PVA (and PAA, if present). Non-limiting examples of crosslinking agent concentrations that may be utilized, based on the total weight of solids, include about 0.1%, about 0.5%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, and the like, as well as a range formed of any two of the above values (a range of from about 0.1% to about 40%, etc.).

[0058] Each of the PVA and PAA may be present in (1) at any concentration and at any ratio that allows the chemical crosslinking agent(s) to form crosslinks and thereby produce the coating. Non-limiting examples of PVA:PAA ratios (by weight) that may be utilized in accordance with the present disclosure include about 5:0.5, about 5:0.6, about 5:0.7, about 5:0.8, about 5:0.9, about 5:1, about 5:1.1, about 5:1.2, about 5:1.3, about 5:1.4, about 5:1.5,and the like, as well as any range formed of two or more of the above ratios (i.e., a range of from about 5:0.5 to about 5:1.5, etc.).

[0059] In certain particular (but non-limiting) embodiments, any of the coating compositions disclosed or otherwise contemplated herein may be in the form of a film for application to a substrate, such as (but not limited to) at least a portion of at least one surface of an article of manufacture. The film may be provided with any thickness that allows the film to function in accordance with the present disclosure. Non-limiting examples of thicknesses that may be utilized include about 1 micron, about 5 microns, about 10 microns, about 25 microns, about 50 microns, about 75 microns, about 100 microns, about 150 microns, about 200 microns, about 250 microns, about 300 microns, about 350 microns, about 400 microns, about 450 microns, about 500 microns, about 550 microns, about 600 microns, about 650 microns, about 700 microns, about 750 microns, about 800 microns, about 850 microns, about 900 microns, about 950 microns, about 1 nm, about 5 nm, about 10 nm, about 25 nm, about 50 nm, about 75 nm, about 100 nm, about 110 nm, about 120 nm, about 130 nm, about 140 nm, about 150 nm, about 160 nm, about 170 nm, about 180 nm, about 190 nm, about 200 nm, or larger, as well as a range formed of any two of the above values (a range of from about 10 microns to about 200 nm, etc.).

[0060] In certain particular (but non-limiting) embodiments, the coating compositions of the present disclosure are substantially free of volatile organic compounds.

[0061] Certain non-limiting embodiments of the present disclosure are directed to an assembly that includes a substrate having at least one surface, and any of the anti-fog and / or anti-frost optically transparent coatings disclosed or otherwise contemplated herein, wherein the coating is disposed on at least a portion of the at least one surface of the substrate. For example, FIG. 2 shows a coating applied to an upper surface of a substrate (upper panel) as well as a coating applied to both the upper surface and lower surface of a substrate (lower panel). In certain particular (but non-limiting) embodiments, the coating comprises polyvinyl alcohol; polyacrylic acid; and at least one organic or inorganic chemical crosslinking agent (and may optionally contain one or more additional components as described or otherwise contemplated herein). In certain particular (but non-limiting) embodiments, the coating is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength and / or is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

[0062] The coatings of the present disclosure may be applied to any substrate for which an anti-fogging and / or anti-frosting characteristic is desired. For example, but not by way of limitation, the substrates utilized in accordance with the present disclosure may have at least a portion of at least one surface that is transparent, translucent, and / or reflective.

[0063] In certain particular (but non-limiting) embodiments, any of the substrates disclosed or otherwise contemplated herein may be an optically transparent polymeric material, and / or glass or its derivatives.

[0064] Any of the assemblies disclosed or otherwise contemplated herein may further comprise an adhesion / primer layer, such as (but not limited to) a coupling agent applied to the substrate to improve adhesion of the coating to the substrate. Non-limiting examples of coupling agents that may be utilized in accordance with the present disclosure include a functional siloxane, like epoxy silane. Non-limiting examples of epoxy silaned that may be utilized in accordance with the present disclosure include (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), and the like, as well as combinations thereof.

[0065] Certain non-limiting embodiments of the present disclosure are directed to a method of producing any of the anti-fog and / or anti-frost optically transparent coatings disclosed or otherwise contemplated herein on any of the substrates disclosed or otherwise contemplated herein (such as, but not limited to, a portion of an article of manufacture). The method includes mixing an aqueous solution comprising a water-soluble polyvinyl alcohol and a water-soluble polyacrylic acid (and optionally one or more additional components as described or otherwise contemplated herein) with an aqueous solution comprising at least one water-soluble, organic or inorganic chemical crosslinking agent to provide a mixture; applying the mixture to at least a portion of at least one surface of the substrate; and curing the mixture applied to the substrate to form the coating. Alternatively, the mixture may be cured into a film prior to applying to the surface of the substrate, whereby the preformed film is thereby applied directly to the substrate.

[0066] The mixture may be applied to the substrate by any methods known in the art or otherwise contemplated herein. Non-limiting examples of application / deposition methods include roll coating, spray coating, dip coating, slot die coating, or curtain coating.

[0067] The curing step may occur at any temperature and under any conditions that cause crosslinking of the PVA and at least one organic or inorganic chemical crosslinking agent (andPAA, if present) and thus form the coating. In certain non-limiting examples, the curing step occurs at ambient temperature and environment. In another non-limiting examples, the curing step involves heating at least a portion of the mixture applied to the substrate to form the coating. When heat is utilized, the mixture may be heated to any temperature that allows for curing of the mixture to form the coating. Non-limiting examples of temperatures that may be utilized in accordance with the present disclosure include about 15°C, about 20°C, about 25°C, about 30°C, about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, about 100°C, about 110°C, about 120°C, about 130°C, about 140°C, about 150°C, about 160°C, about 170°C, about 180°C, about 190°C, about 200°C, and the like, as well as a range formed from any two of the above values (e.g., a range of from about 15°C to about 25°C, a range of from about 100°C to about 190°C, etc.).

[0068] In certain particular (but non-limiting) embodiments, the method is performed substantially in the absence of volatile organic compounds.

[0069] In certain particular (but non-limiting) embodiments, the method is performed at a point of manufacture of the substrate / article of manufacture. In other non-limiting embodiments, the coating is provided in the form of a film that can be applied at the point of manufacture, in the field, and / or at the point of use.

[0070] The methods of the present disclosure may include one or more optional additional steps. Non-limiting examples of optional additional steps include degassing of the mixture, adjusting the pH of the mixture, sonication of the mixture, resting of the mixture, and / or application of one or more additional layers to a substrate (either prior to or after application of the coating), and the like.

[0071] In certain particular (but non-limiting) embodiments, the method may further comprise the step of applying a coupling agent and / or an adhesion / primer layer to the surface of the substrate prior to application of the mixture thereto to improve adhesion of the coating to the substrate. Non-limiting examples of coupling agents that may be utilized in accordance with the present disclosure include a functional siloxane, like epoxy silane. Non-limiting examples of epoxy silanes that may be utilized in accordance with the present disclosure include (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), and the like, as well as combinations thereof.

[0072] Certain non-limiting embodiments of the present disclosure relate to a coating formulation for preparing a hydrophilic coating for optical surfaces to mitigate the scatteringeffect and reduction of optics due to condensation or freezing of water vapor droplets. The coating formulation may have any of the formulations disclosed or otherwise contemplated herein.

[0073] Certain non-limiting embodiments of the present disclosure relate to processes of making an anti-fog / anti-frost coating (AFC) composition comprising the steps of preparing an aqueous dispersion of polyvinyl alcohol (PVA) and at least one organic or inorganic crosslinking agent (CLA).

[0074] Certain non-limiting embodiments of the present disclosure also relate to a coating composition as obtained with said process, and to a process of applying the anti-fog coating on a substrate using such composition, and to the resulting coated substrate.

[0075] In certain particular (but non-limiting) embodiments, the present disclosure results in a coating on a substrate that has a thickness in a range of from about 200 nm to about 10 microns and possesses the characteristics of being hygroscopic, abrasion resistant, anti-fog, and / or anti-frost in nature.

[0076] Certain non-limiting embodiments of the present disclosure are directed to a method of making an anti-fog / anti-frost coating comprising the steps of: preparing, in water, a solution of water-soluble polymers and adding at least one water-borne organic or inorganic chemical crosslinking agent to the solution, thereby resulting in an aqueous medium of pH 1- 9. In certain particular (but non-limiting) embodiments, the at least one water-borne organic crosslinking agent comprises a di- or poly- aldehyde (such as (but not limited to, glyoxal, acetaldehyde, glycolaldehyde, propanediol, and / or methylglyoxal), which may be used with polyvinyl alcohol in a ratio in a range of from about 5:0 to about 5:2 by weight. In certain particular (but non-limiting) embodiments, the dialdehyde is present in said coating in an amount of about 0.1% to about 40% based on the total weight of solids in said coating, and / or the at least one polyacrylic acid crosslinker is present in said coating in an amount of about 0.1% to about 40% based on the total weight of solids in said coating. In addition, the pH range of the water may be between about 1 to about 5, such as (but not limited to) between about 3 to about 4.

[0077] Certain non-limiting embodiments of the present disclosure are directed to a method of making an anti-fog / anti-frost coating comprising the steps of: preparing, in water, a solution of water-soluble polymers; and adding inorganic metal oxides, or alkoxides to the solution, thereby resulting in an aqueous medium of pH 1-9. In certain particular (but non-limiting) embodiments, the inorganic metal oxides may constitute hydrolyzed alkoxides or nanoparticles (such as, but not limited to, silica nanoparticles) thereof. For example (but not by way of limitation), the hydrolyzed inorganic oxides may include hydrolyzed metal alkoxides, and the hydrolyzed metal alkoxides are added such that the hydrolyzed metal alkoxides are present in said coating in an amount of about 0.1% to about 10% based on the total weight of solids in said coating. Non-limiting examples of hydrolyzed metal alkoxides include at least one of titanium isopropoxide, titanium ethoxide, zirconium ethoxide, tetraethyl orthosilicate, tetramethylorthosilicate, (3-glycidyloxypropyl)trimethoxysilane (3- GPTMS), tetraethoxysilane (TEOS), aluminum isopropoxide, aluminum sec butoxide, vanadyl isopropoxide, niobium ethoxide, tantalum ethoxide, or potassium tert-butoxide. In certain particular (but non-limiting) embodiments, the method may further include curing said coating at a temperature in a range of from about room / ambient temperature to about 190°C to form an anti-fog and / or anti-frost coating (such as, but not limited to, a range of from 100°C to about 190°C, or a range of from about 90°C to about 150°C, or a range of from about room / ambient temperature to about 110°C, etc.). Table 1 below describes various exemplary procedures for use of the primary cross-linking agents in accordance with the present disclosure (see also FIG. 3).TABLE 1

[0078] Certain non-limiting embodiments of the present disclosure are directed to a method of making an anti-fog / anti-frost coating comprising the steps of: preparing, in water, a mixture of water-soluble polymers (such as, but not limited to, a mixture of polyvinyl alcohols A); and adding at least one organic crosslinking agent possessing carboxylic functional groups (such as, but not limited to, di-, tri-, or poly- carboxylic moieties (such as citric acid, maleic acid, or poly acrylic acid). In certain particular (but non-limiting)embodiments, the ratio of polymers to crosslinking agent(s) is in a range of from about 5:0.5 to about 5:2 by weight.

[0079] Certain non-limiting embodiments of the present disclosure are directed to a method of forming an anti-fog and / or anti-frost optically transparent coating on a substrate, comprising the steps of: depositing polyvinyl alcohol and at least one crosslinking agent including, inorganic metal oxides, hydrolyzed alkoxides, acrylic acid polymer, and dialdehyde; and curing the deposited polyvinyl alcohol and at least one crosslinking agent. The curing step may be performed by any of the methods disclosed herein, including (but not limited to), at ambient temperatures for less than about 24 hours or at temperatures in a range of from about ambient temperature to about 150°C.

[0080] Certain non-limiting embodiments of the present disclosure are directed to an anti-fog and / or anti-frost coating that comprises a hygroscopic polyvinyl alcohol layer. The hygroscopic polyvinyl alcohol layer may comprise, in certain non-limiting embodiments, at least one of a polyvinyl alcohol; at least one inorganic crosslinking component and / or at least one organic crosslinking component (such as, but not limited to, an inorganic metal oxide, or alkoxide in the range of about 0.1% to about 10% based on the total weight of solids; or di- or poly- aldehyde, or polyacrylic acid, in the range of about 0.1% to about 40% based on total weight of solids in said coating).

[0081] FIG. 1 provides a flow diagram showing one non-limiting embodiment of a process for producing an anti-fog and / or anti-frost coating in accordance with the present disclosure, as described in detail herein below.

[0082] Path 1 of FIG. 1: PVA is crosslinked via condensation reaction with metal oxides containing surface hydroxyls (-OH groups). Condensation reaction can take place at room temperature over the course of days or weeks -OR- at elevated temperature, for example 120°C for 10 minutes.

[0083] Path 2 of FIG. 1: PVA is crosslinked primarily PAA, in addition to a secondary organic crosslinking agent. Hydrolysable components (alkoxides, not water soluble) require acidic or basic pH for hydrolysis (which renders them water-borne). For path 2, appropriate pH is accomplished by addition of PAA (which is mildly acidic). PVA and PAA crosslink via esterification reaction, which requires heating to proceed at an appreciable rate (for example, but not by way of limitation, 140 -160°C for 5 - 15 minutes).

[0084] Path 3 of FIG. 1: PVA is crosslinked using secondary organic crosslinking agents. In the case of alkoxides, will require pH adjustment (in the absence of PAA) to facilitate hydrolysis (rendering them water-borne). In the case metal alkoxides are used, curing will take place over the course of a few days at ambient, or can be accomplished more rapidly by, for example, heating to 110°C for 10 minutes to force the condensation reaction to proceed by the removal of water.

[0085] Path 4 of FIG.l: PVA is crosslinked primarily with PAA. Inorganic metal oxide is included for additional functionality and / or increased mechanical properties, as well as contributing to crosslinking of the PVA. Since PVA and PAA crosslink via esterification, heating is again used (for example, but not by way of limitation, 140 -160°C for 5 - 15 minutes).EXAMPLES

[0086] Examples are provided hereinbelow. However, the present disclosure is to be understood to not be limited in its application to the specific experimentation, results, and laboratory procedures disclosed herein after. Rather, the Examples are simply provided as one of various embodiments and are meant to be exemplary, not exhaustive.

[0087] Example 1:

[0088] 10 grams of polyvinyl alcohol (Selvol E575) was dissolved in 100 ml deionized water(DI) at 95°C under stirring for 4 hours or until solids were fully dissolved. The resulting solution was then allowed to cool to ambient temperature to obtain a clear, fully dissolved PVA solution which was further diluted to a final solids content of 5 wt%. To this, 8 ml of 25 wt% poly acrylic acid and 5 ml of 40 wt% glyoxal were added dropwise under vigorous stirring after which the intensity was reduced and allowed to continue for 4 hours. The coating solution was then allowed to rest for 24 hours before use. The coating solution was then applied to a glass substrate by spin coating at 1 kRPMs for 10 seconds, where it was then allowed to dry at ambient temperature before being heat-treated at 150°C for 15 minutes.

[0089] Example 2:

[0090] 10 grams of PVA (Poval 25-98R, Silanol functionalized) was dissolved in 100 ml deionized water (DI) at 95°C under stirring for 4 hours or until solids were fully dissolved. The resulting solution was then allowed to cool to ambient temperature to obtain a clear, fully dissolved PVA solution, which was further diluted to a final solids content of 5 wt%. To this, a silica nanoparticle dispersion was added under stirring so that the final silica:PVA ratio wasaround 4:5, and further diluted so that the final PVA concentration was 5 wt%. The coating solution was then allowed to rest for 24 hours before use. The coating solution was then applied to a glass substrate by spin coating at 1 kRPMs for 10 seconds, where it was then allowed to dry at ambient before being heat treated at 150°C for 20 minutes.

[0091] Example 3:

[0092] To hydrolyze titanium (IV) isopropoxide (97%), 2 ml of titanium (IV) isopropoxide (97%) and 2 ml of nitric acid (65 wt.%) were added into 50 ml deionized water and stirred vigorously for 24 hours at room temperature. 1 ml of hydrolyzed titanium isopropoxide was added into 3 ml of 1 wt% SELVOL E575 polyvinyl alcohol (high molecular weight (180,000 - 215,000), partially hydrolyzed (65%-90%)) under continuous stirring. The resulting solution was coated onto a microscope slide by spin coating 3 mL of solution at a speed of 4000 rpm. The coated slide was cured at 150°C for 5 minutes.

[0093] Example 4:

[0094] 1 ml of glyoxal (40 wt.%) and 1 ml of polyacrylic acid (25 wt.%, molecular weight250,000) was added into 5 ml of 3 wt% SELVOL E575 polyvinyl alcohol (high molecular weight (180,000 -215,000), partially hydrolyzed (65%-90%)) under continuous stirring. The resulting solution was coated onto a microscope slide by spin coating 3 mL of solution at a speed of 4000 rpm. The coated slide was cured at 150°C for 5 minutes.

[0095] Example 5:

[0096] To hydrolyze titanium (IV) isopropoxide (97%), 2 ml of titanium (IV) isopropoxide (97%) and 2 ml of nitric acid (65 wt.%) were added into 50 ml deionized water and stirred vigorously for 24 hours at room temperature. 1 ml of hydrolyzed titanium isopropoxide, 1 ml of glyoxal (40 wt.%), and 1 ml of polyacrylic acid (25 wt.%, molecular weight 250,000) were added into 3 ml of 1 wt% SELVOL E575 polyvinyl alcohol (high molecular weight (180,000 - 215,000), partially hydrolyzed (65%-90%)) under continuous stirring. The resulting solution was coated onto a microscope slide by spin coating 3 mL of solution at a speed of 4000 rpm. The coated slide was cured at 150°C for 5 minutes.

[0097] Like other wet-coating processes, the present disclosure benefits from multiple known inclusions that improve the robustness of the achieved film and the quality achieved from the coating process. For example, glass substrates were coated with the coating solution produced in Example 5, and at least one surfactant was utilized to increase the wettability of the surface to be coated. This surfactant was chosen based on the properties of the substrateand was optimized based on use requirements. In a particular (but non-limiting) embodiment, the at least one surfactant comprises a polyoxyethylene ether nonionic fluorosurfactant (such as, but not limited to, CAPSTONE® FS-30, Dupont Chemicals Company, Wilmington, DE).

[0098] As an additional example, the coating solution produced in Example 5 was coated on polycarbonate substrates utilizing a coupling agent, or primer layer, to improve adhesion to the substrate. Mechanical strength can be improved when coated on polycarbonate by using a functional siloxane, such as (but not limited to) epoxy silane, as a coupling agent. Likewise, the silane coupling agent can be used as a coupling agent on glass substrates since reactive silanol groups will be reactive toward PVA hydroxyls as well as glass surface hydroxyls. Coupling agents and priming layers are chosen based on the properties of the substrate, and can be optimized based on use requirements.

[0099] Example 6:

[0100] The coating solution produced in sample 5 was deposited on a glass substrate using a roll coating method. The sample was dried in a drying tunnel at 90°C for 5 minutes. The drying process removed the water from the film resulting in the formation of a film.

[0101] After drying, the sample was placed in a convection oven for curing at 150°C for 5 minutes. The curing process resulted in appropriate crosslinking to provide a mechanically robust film with hygroscopic properties.

[0102] Coated substrates were produced using this process with coating thicknesses in the range of 100 nm to 10 microns. The anti-fog properties were measured by exposing the samples to water vapor produced by heating a container of water to 90°C. It was found that the exposure time required to generate fog on the coated substrates increased with greater coating thickness. This provides a method to optimize the coating performance based on enduse requirements by changing the coating thickness.

[0103] Transmission Results:

[0104] FIG. 4 contains plots of the transmittance of the bare glass and the sample prepared in Example 1 after curing at 150°C. The coated sample in Example 1 has less than 1% transmission loss at 550 nm wavelength.

[0105] Mechanical Durability:

[0106] Surface Hardness: Surface hardness of the coated samples was measured by using the pencil hardness test (Wolff-Wilborn test), where a graphite pencil of a known hardness ismoved across the coating under certain pressure at a specified angle. Pencil hardness of greater than 2H was achieved for coatings produced according to Example 5.

[0107] Abrasion Resistance (FIG. 5): The sample produced in Example 5 was subjected to a felt-abrasion test as specified by EN 1096-2 for 500 strokes. The sample was evaluated after testing for both visible damage and anti-fog performance. The coating was found to show no visible signs of damage when viewed at a distance of 24 inches under room lighting. Additionally, the abraded area showed no degradation in the anti-fog behavior relative to the unabraded area when exposed to 100°C steam for 5 seconds.

[0108] Example 7:

[0109] Below are lists of various materials that have been utilized to produce various embodiments of the water-based polymer anti-fog coating for glass or other transparent substrates. This list is for purposes of example only and is not meant to be all inclusive.

[0110] Non-limiting examples of PVA (Polyvinyl alcohol) that have been utilized include Kuraray Poval 5-88 (88% hydrolyzed, low molecular weight which is indicated by the 5, i.e. 5 cP viscosity at 4 wt% solution); higher or lower molecular weight PVAs; varying hydrolysis levels of PVA; silanol functional, amino functional, PEGylated, and other functionalized PVAs; and the like.

[0111] One non-limiting example of a PAA (Poly Acrylic acid) includes BASF Sokalan PA80S, 35 wt% solution.

[0112] One non-limiting example of a fluorosurfactant includes FS-30 (Chempoint Chemours FS-30 - PEGylated fluorocarbon surfactant).

[0113] Non-limiting examples of anionic surfactants include SDS (Sodium Dodecyl sulfate), SDBS (Sodium dodecylbenzene sulfonate), Ammonium lauryl Sulfate, and the like.

[0114] Non-limiting examples of non-ionic surfactants include DGDME (Decaethyleneglycol monododecyl ether, non-ionic surfactant), cocoglucoside, poloxamers, Tweens, and the like.

[0115] Non-limiting examples of silanes include 3-GPTMS (3-glycydoxypropyl trimethoxy silane), TEOS (tetraethoxysilane), Tris 3-trimethoxysilyl propyl isocyanurate, aminopropyl triethoxysilane, and the like.

[0116] Non-limiting examples of silica nanoparticles include various silica particles (ST-O, CT20DH, CC301, other acidic aqueous particles, epoxy functionalized particles, or deionizedparticles), as well as PEGylated silica nanoparticles, epoxy functionalized particles, and other functionalized silica nanoparticles, and the like.

[0117] Non-limiting examples of acids include hydrochloric acid, acetic acid, citric acid, and other di- or poly carboxylic acids, and the like. The carboxylic acids can also act as crosslinkers.

[0118] Non-limiting examples of additional optional ingredients that can be added include the following: sugar alcohols; cel lulosics (sodium alginate, xanthan gum, etc.); slip additives (Evonik Tego line, BYK, and others; to increase scratch resistance); micronized silica and silicones (to increase scratch resistance); PEG and PEGylated compounds; glycols and glycol ethers; various MW of PAA; various MW and hydrolysis levels of PVA; polyether modified polysiloxanes; other silanes and combinations thereof, such as (but not limited to) PEGylated silanes; 3-Aminopropyltriethoxy silane; 3-Ureidopropyltrimethoxy silane; Tris[3- (trimethyoxysilyl)propyl)isocyanurate; 3-(trimethoxysilyl)propyl methacrylate; triethoxysilylpropoxy(polyethyleneoxy)dodecandoate; l,2-Bis(Trimethoxysilyl)decane; N,N'- bis-[(3-triethoxysilylpropyl)aminocarbonyl]polyethylene oxide; and the like; as well as any combinations thereof.

[0119] Example 8:

[0120] This Example utilized PVA, PAA, 0.2 ml FS-30 (Chempoint Chemours FS-30 PEGylated fluorocarbon surfactant), and 0.2 ml 3-GPTMS (3-glycydoxypropyl trimethoxy silane). 100 ml of 10 wt% solution of PVA and 5.7 g PAA at 35 wt% stock were combined; alternatively, the PVA and PAA may be premixed at a 5:1 ratio by weight solids as a stock solution, with no shelf life or other issues. Reagents were combined on a stir plate with good vortex. There is no sensitivity to mixing order or timing. The ingredients were mixed well for 15 minutes before use while trying to avoid incorporation of bubbles. The solution may be good for up to one month (although it is desirable that the solution be used within one week).

[0121] Example 9:

[0122] This Example utilized the same ingredients and production method as in Example 8, except that 2% 3-GPTMS (i.e., 2 ml of 3-GPTMS) was used instead of 0.2%. This formulation possesses improved cleanability, scratch resistance, and overall mechanical properties. The formulation of Example 8 has a "tackiness" to it when wet, making it slightly harder to clean. However, the formulation of Example 8 also possesses generally better anti-fog performance than Example 9.

[0123] Example 10:

[0124] This Example utilized 100 ml 10 wt% PVA, 5.7 g PAA 35 wt% stock, 0.2 ml FS-30, 4 ml 11 wt% SDS, 2 ml 3-GPTMS, and 0.5 ml PCH2 (see Example 13 for recipe). The reagents were combined using the mixing instructions of Example 8.

[0125] This iteration had a well-balanced performance on the suite of tests conducted without lacking drastically on any one test.

[0126] Example 11:

[0127] This Example utilized 100 ml 10 wt% PVA, 5.7 g PAA 35 wt% stock, 3 ml 1% v / v FS- 30, 0.4 ml TEOS, 2 ml 10 wt% SDS, 0.25 ml 3-GPTMS, 3 ml ST-0-25. The first 5 ingredients were mixed and allowed to stir / hydrolyze for 30 minutes. Then the remaining ingredients were added and allowed to stir / hydrolyze for an additional 15 minutes.

[0128] This formulation possessed very good cleanability and scratch resistance, while also doing well on most of the other tests.

[0129] Example 12:

[0130] This Example utilized 100 ml 10% PVA, 5.7 g PAD1 (see Example 14 for recipe), 1 ml 10 wt% SDS, 0.25 ml 3-GPTMS, 0.4 ml TEOS, 6.5 ml ST-O, and 4 ml 10wt% SDS.

[0131] The first 3 ingredients were mixed under stirring, followed by addition of the 3- GPTMS and TEOS. The resultant mixture was allowed to stir / hydrolyze for 30 minutes. While the mixture was mixing, the ST-0 and remaining SDS were combined in a separate container. When the mixing time was completed, the combined ST-0 and SDS were added to the remaining solution. Combining the ST-0 silica nanoparticles and SDS surfactant prior to addition to the remainder of ingredients prevents the solution and final film from being hazy.

[0132] This formulation performed well on all tests.

[0133] Example 13:

[0134] PCH2

[0135] One of the early challenges with certain formulations was diminished anti-fog performance over time, especially with exposure to water. While not wishing to be bound by any theory, it was assumed that the FS30 was simply diffusing out of the coating over time, since there was no chemical bonding to retain the surfactant. A number of various strategies, including reacting non-ionic surfactants with isocyanate functional silanes, were utilized. In another iteration, the silane was reacted with the surfactant to "anchor" it into the coating. While not wishing to be bound by theory, it is possible that the hydrolyzed silane should beable to react with some of the pendant -OH groups on the non-ionic surfactant. The use of PCH2 provided much better performance on chemical and water exposure tests.

[0136] The production of PCH2 began with 100 ml DI water, pH adjusted to 3 by HCL. 5 ml 3GPTMS was added under stirring, and waited for hydrolysis to complete (solution goes from hazy to clear, plus an additional 5 - 15 minutes to ensure hydrolysis is complete). 5 grams of DGDME was added until fully dissolved (it is a waxy substance at room temperature, so this can be sped up by gentle heating). Once this step was complete, the beaker was placed into a pressure cooker, and a 30 min cycle was run (at approximately 1.3 ATM and 110°C). This drives the esterification reaction between the silane and the surfactant. The esterification reaction may be accomplished at much lower temperatures, but based on literature, a temperature was targeted near or above 100°C. However, some later experiments indicate that the esterification may be accomplished at even lower temperatures, such as 60°C, or even at room temperature.

[0137] Example 14:

[0138] PAD1

[0139] PAA was reacted with non-ionic surfactant through elevated temperature and / or pressure to "anchor" the surfactant to the PAA.

[0140] In one particular (but non-limiting) experiment, 100 g Sokalan PA80S (PAA, 35 wt% in water) and 1 g Decaethylene glycol monododecyl ether (DGDME) were utilized. TheDGDME was dissolved in the PAA solution under stirring. Once fully dissolved, the mixture was heated to 130°C under pressure for 30 minutes and allowed to cool back to ambient. The resultant solution is now ready to use in the final formulation. Same as for PCH2, this drives the esterification reaction between the silane and the surfactant. The esterification may be accomplished at much lower temperatures, but based on literature, a temperature was targeted near or above 100°C. Some later experiments indicate that this may be accomplished at even lower temperatures, such as 60°C or even at room temperature. This reaction may further be catalyzed using an acid, such as (but not limited to) sulfuric acid.

[0141] Example 15:

[0142] Novel trends discovered in the Development stage

[0143] Surfactant "Anchoring"

[0144] By taking advantage of the primary alcohol groups present on PEG, non-ionic surfactants, or biopolymers such as cellulosics, it was found that these compounds can beanchored into the final film by first pre-reacting them with carboxylic groups (such as (but not limited to) on PAA) or silanes (such as (but not limited to) 3-GPTMS). This results in a more long lasting anti-fog / hydrophilic effect on the final film.

[0145] Nanoparticle stabilization through micellization

[0146] Addition of an anionic surfactant in quantities sufficient to yield a micellar layer between nonionic surfactants / polymers and silica nanoparticles "protects" the particles from destabilizing and consequently agglomerating. The surfactant should be added to the nanoparticle solution before incorporation with the nonionic surfactant to prevent haze of the final coating.

[0147] Alternative Metal alkoxide crosslinkers

[0148] Metal alkoxide alternatives to silanes may be added as more reactive / more hydrophilic crosslinkers. Non-limiting examples thereof include tetraethoxy silane, aluminum sec-butoxide, titanium isopropoxide, zirconium propoxide, and the like.

[0149] Metal alkoxides, which are highly reactive with water, incorporate poorly in the water-based polymer medium without a stabilizing agent. Therefore, a chelating compound such as (but not limited to) acetic acid or ethylacetoacetate can be added to slow the rate of hydrolysis and condensation such that the metal alkoxide reacts more homogeneously into the film.

[0150] Ring-opening reactions with various products

[0151] One of the main production challenges is a lack of hydrophilicity after rinsing or extended exposure to water. The source of this issue arose when the surfactant leached out of the coating. By utilizing maleic anhydride, additives such as (but not limited to) fluorinated surfactants and hydrophilic silica particles could be reacted to bind to epoxy-functionalized silanes. To address this issue, a series of experiments were conducted that aimed at binding the proprietary, fluorinated surfactant to the epoxy-functionalized silane via a combination of maleic anhydride, maleic acid, and a mixture of the two. Results indicated that surfactant leaching was minimized.

[0152] pH adjustment to address crosslinking

[0153] The goal for the curing step was a ramped, short duration process, that would mimic available and common industrial equipment and practices. This was a challenge because the coatings tend to cross-link less at shorter cure times. Therefore, mechanical properties are reduced when ramp cured versus the steady 30 min cure profile that wasinitially used. By using weak and strong acids, it was possible to achieve stronger coatings via acid-catalyzed hydrolysis and acid-catalyzed esterification.

[0154] Sil ica nanoparticles

[0155] Nanoparticles can impart mechanical strength to the polymer film but may also have incompatibilities resulting in haze or other issues. This can be addressed by pH-adjusting the PAA with a strong base, diluting the fluorinated surfactant, and / or pretreating the silica nanoparticles with anionic surfactant (such as, but not limited to, SDS) prior to being added to the final coating material, or any combination of thereof.

[0156] Example 16:

[0157] Examples of testing utilized

[0158] Time To Fog (TTF): the basic set up forTTF testing is shown in FIG. 6. In the analysis, a sample should pass 60 seconds without fogging.

[0159] Cleanability: in this analysis, the sample is sprayed with a commercially available ammonia-based glass cleaning product (such as, but not limited to, Windex) and cleaned with a common household paper towel and rubbed until dry. There should be no scratching or failure of the film. The film should not feel tacky or prone to collecting lint.

[0160] Dry B rush Test (DBT): this analysis is based on ASTM D2486 and uses a device such as (but not limited to) BGD 526 (Wet Abrasion Scrub Tester; Biuged Laboratory Instruments (Guangzhou) Co., Ltd; Guangzhou, China) to rub a nylon brush over the coating. The desired result is to pass 1500 cycles at 37 cycles per minute. The metric for "pass" is performance with very minimal scratching, as represented by a higher silane control.

[0161] Chemical Resistance Testing: This is a submersion test that utilizes, separately, in three different baths: (i) tap water; (ii) 1 M HCI; and (iii) 1 M NaOH. Samples are submerged in each bath for 1 hour, then rinsed, dried, and evaluated for damage. Any damage should be noted. If no or minimal damage, the TTF test should be reperformed to see if performance is degraded by exposure to chemicals.

[0162] Example 17:

[0163] Summary of results

[0164] The results for the different formulations of Examples 8-13 in the performance analyses of Example 16 (including haze, cleanability, tap water submersion, 1 M HCI submersion, 1 M NaOH submersion, and time to fog) are shown in Table 2. Table 3 contains the performance metrics for each test.TABLE 2: Qualitative Performance Rankings of Different FormulationsTABLE 3: Performance Metrics for Each TestNON-LIMITING ILLUSTRATIVE EMBODIMENTS

[0165] The following is a list of non-limiting illustrative embodiments disclosed herein:

[0166] Illustrative embodiment 1. A system for producing an anti-fog and / or anti-frost optically transparent coating, the system comprising: (1) an aqueous solution comprising a water-soluble polyvinyl alcohol; and (2) at least one of: (a) an aqueous solution comprising atleast one water-soluble, organic or inorganic chemical crosslinking agent; and / or (b) a hydrolysable metal-alkoxide.

[0167] Illustrative embodiment 2. The system of Illustrative embodiment 1, wherein (1) further comprises a water-soluble polyacrylic acid.

[0168] Illustrative embodiment 3. The system of Illustrative embodiment 2, wherein (1) contains a polyvinyl alcohol: polyacrylic acid ratio in a range of from about 5:0.5 to about 5:1.5 by weight.

[0169] Illustrative embodiment 4. The system of any one of Illustrative embodiments 1-3, wherein the at least one crosslinking agent of (2) is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, a silane, and combinations thereof.

[0170] Illustrative embodiment 5. The system of any one of Illustrative embodiments 1-4, wherein the at least one crosslinking agent of (2) is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

[0171] Illustrative embodiment 5a. The system of Illustrative embodiment 5, wherein the at least one crosslinking agent of (2) comprises (3-glycidyloxypropyl)trimethoxysilane (3- GPTMS) and / or tetraethoxysilane (TEOS).

[0172] Illustrative embodiment 5b. The system of Illustrative embodiment 5 or 5a, wherein the at least one crosslinking agent of (2) comprises a PEG silane.

[0173] Illustrative embodiment 5c. The system of Illustrative embodiment 5b, wherein the PEG silane comprises triethoxysilylpropoxy(polyethyleneoxy)dodecandoate.

[0174] Illustrative embodiment 5d. The system of any one of Illustrative embodiments 5- 5c, wherein the at least one crosslinking agent of (2) comprises a Dipodal silane.

[0175] Illustrative embodiment 5e. The system of Illustrative embodiment 5d, wherein the Dipodal silane comprises 1,2-Bis(trimethoxysilyl)decane.

[0176] Illustrative embodiment 6. The system of any one of Illustrative embodiments 1- 5e, wherein the at least one crosslinking agent is present in (2) at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

[0177] Illustrative embodiment 7. The system of any one of Illustrative embodiment 1-6, further comprising instructions for combining (1) and (2) to produce the anti-fog and / or antifrost coating on a substrate.

[0178] Illustrative embodiment 8. The system of any one of Illustrative embodiments 1-7 , wherein the system is substantially free of volatile organic compounds.

[0179] Illustrative embodiment 9. The system of any one of Illustrative embodiments 1-8, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

[0180] Illustrative embodiment 10. The system of any one of Illustrative embodiments 1-9, further comprising at least one surfactant.

[0181] Illustrative embodiment 10a. The system of Illustrative embodiment 10, wherein the at least one surfactant is a polyoxyethylene ether nonionic fluorosurfactant.

[0182] Illustrative embodiment 11. The system of any one of Illustrative embodiments 1- 10a, further comprising at least one coupling agent.

[0183] Illustrative embodiment 11a. The system of Illustrative embodiments 11, wherein the at least one coupling agent comprises (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS) and / or tetraethoxysilane (TEOS).

[0184] Illustrative embodiment lib. The system of any one of Illustrative embodiments 1-lla, further comprising at least one additional component selected from the group consisting of a slip additive, fumed silica, silica nanoparticles, organically modified silica nanoparticles, a cellulosic, a saccharide, a biopolymer, sodium alginate / alginic acid, and combinations thereof.

[0185] Illustrative embodiment 12. An anti-fog and / or anti-frost coating composition, the composition comprising: polyvinyl alcohol; and at least one organic or inorganic chemical crosslinking agent; and wherein the coating composition is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength.

[0186] Illustrative embodiment 13. The coating composition of Illustrative embodiment12, further comprising polyacrylic acid.

[0187] Illustrative embodiment 13a. The coating composition of Illustrative embodiment 13, wherein polyvinyl alcohol and polyacrylic acid are present in a polyvinyl alcohokpolyacrylic acid ratio in a range of from about 5:0.5 to about 5:1.5 by weight.

[0188] Illustrative embodiment 14. The coating composition of Illustrative embodiment 12 or 13, wherein the coating composition is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

[0189] Illustrative embodiment 15. The coating composition of any of Illustrative embodiments 12-14, wherein the at least one crosslinking agent is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, and combinations thereof.

[0190] Illustrative embodiment 16. The coating composition of any one of Illustrative embodiments 12-15, wherein the at least one crosslinking agent is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

[0191] Illustrative embodiment 16a. The coating composition of Illustrative embodiment 16, wherein the at least one crosslinking agent comprises (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS) and / or tetraethoxysilane (TEOS).

[0192] Illustrative embodiment 16b. The coating composition of Illustrative embodiment 16 or 16a, wherein the at least one crosslinking agent comprises a PEG silane.

[0193] Illustrative embodiment 16c. The coating composition of Illustrative embodiment 16b, wherein the PEG silane comprises triethoxysilylpropoxy (polyethyleneoxy)dodecandoate.

[0194] Illustrative embodiment 16d. The coating composition of any one of Illustrative embodiments 16-16c, wherein the at least one crosslinking agent comprises a Dipodal silane.

[0195] Illustrative embodiment 16e. The coating composition of Illustrative embodiment 16d, wherein the Dipodal silane comprises 1,2-Bis(trimethoxysilyl)decane.

[0196] Illustrative embodiment 17. The coating composition of any one of Illustrative embodiment 12-16e, wherein the at least one crosslinking agent is present in the coatingcomposition at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

[0197] Illustrative embodiment 18. The coating composition of any one of Illustrative embodiments 12-17, further defined as a film for application to at least a portion of at least one surface of an article of manufacture.

[0198] Illustrative embodiment 19. The coating composition of Illustrative embodiment 18, wherein the film has a thickness in a range of from about 10 microns to about 200 nm.

[0199] Illustrative embodiment 20. The coating composition of any one of Illustrative embodiments 12-19, wherein the coating composition is substantially free of volatile organic compounds.

[0200] Illustrative embodiment 21. The coating composition of any one of Illustrative embodiments 12-20, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

[0201] Illustrative embodiment 22. The coating composition of any one of Illustrative embodiments 12-21, further comprising at least one surfactant.

[0202] Illustrative embodiment 22a. The coating composition of Illustrative embodiment22, wherein the at least one surfactant is a polyoxyethylene ether nonionic fluorosurfactant.

[0203] Illustrative embodiment 23. The coating composition of any one of Illustrative embodiments 12-22a, further comprising at least one coupling agent.

[0204] Illustrative embodiment 23a. The coating composition of Illustrative embodiment23, wherein the at least one coupling agent comprises (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS) and / or tetraethoxysilane (TEOS).

[0205] Illustrative embodiment 23b. The coating composition of any one of Illustrative embodiments 12-23a, further comprising at least one additional component selected from the group consisting of a slip additive, fumed silica, silica nanoparticles, organically modified silica nanoparticles, a cellulosic, a saccharide, a biopolymer, sodium alginate / alginic acid, and combinations thereof.

[0206] Illustrative embodiment 24. An assembly, comprising: a substrate having at least one surface; and an anti-fog and / or anti-frost optically transparent coating disposed on at least a portion of the at least one surface of the substrate, wherein the coating comprises: polyvinyl alcohol; and at least one organic or inorganic chemical crosslinking agent; andwherein the coating is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength.

[0207] Illustrative embodiment 25. The assembly of Illustrative embodiment 24, wherein the coating further comprises polyacrylic acid.

[0208] Illustrative embodiment 25a. The assembly of Illustrative embodiment 25, wherein polyvinyl alcohol and polyacrylic acid are present in a polyvinyl alcohokpolyacrylic acid ratio in a range of from about 5:0.5 to about 5:1.5 by weight.

[0209] Illustrative embodiment 26. The assembly of Illustrative embodiment 24 or 25, wherein the coating is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

[0210] Illustrative embodiment 27. The assembly of any one of Illustrative embodiments 24-26, wherein the at least one crosslinking agent is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, and combinations thereof.

[0211] Illustrative embodiment 28. The assembly of any one of Illustrative embodiments 24-27, wherein the at least one crosslinking agent is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

[0212] Illustrative embodiment 28a. The assembly of Illustrative embodiment 28, wherein the at least one crosslinking agent comprises (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS) and / or tetraethoxysilane (TEOS).

[0213] Illustrative embodiment 28b. The assembly of Illustrative embodiment 28 or 28a, wherein the at least one crosslinking agent comprises a PEG silane.

[0214] Illustrative embodiment 28c. The assembly of Illustrative embodiment 28b, wherein the PEG silane comprises triethoxysilylpropoxy(polyethyleneoxy)dodecandoate.

[0215] Illustrative embodiment 28d. The assembly of any one of Illustrative embodiments 28-28c, wherein the at least one crosslinking agent comprises a Dipodal silane.

[0216] Illustrative embodiment 29e. The assembly of Illustrative embodiment 28d, wherein the Dipodal silane comprises 1,2-Bis(trimethoxysilyl)decane.

[0217] Illustrative embodiment 30. The assembly of any one of Illustrative embodiments 24-29e, wherein the at least one crosslinking agent is present in the coating at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

[0218] Illustrative embodiment 31. The assembly of any one of Illustrative embodiments 24-30, wherein the coating has a thickness in a range of from about 10 microns to about 200 nm.

[0219] Illustrative embodiment 32. The assembly of any one of Illustrative embodiments 24-31, wherein the surface of the substrate to which the coating is applied is transparent, translucent, and / or reflective.

[0220] Illustrative embodiment 33. The assembly of any one of Illustrative embodiments 24-32, wherein the coating is substantially free of volatile organic compounds.

[0221] Illustrative embodiment 34. The assembly of any one of Illustrative embodiments 24-33, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

[0222] Illustrative embodiment 35. The assembly of any one of Illustrative embodiments 24-34, wherein the coating further comprises at least one surfactant.

[0223] Illustrative embodiment 35a. The assembly of Illustrative embodiment 35, wherein the at least one surfactant comprises a polyoxyethylene ether nonionic fluorosurfactant.

[0224] Illustrative embodiment 36. The assembly of any one of Illustrative embodiments 24-35a, wherein the coating further comprises at least one coupling agent.

[0225] Illustrative embodiment 36a. The assembly of Illustrative embodiment 36, wherein the at least one coupling agent comprises (3-glycidyloxypropyl)trimethoxysilane (3- GPTMS) and / or tetraethoxysilane (TEOS).

[0226] Illustrative embodiment 36b. The assembly of any one of Illustrative embodiments 24-36a, wherein the coating further comprises at least one additional component selected from the group consisting of a slip additive, fumed silica, silica nanoparticles, organically modified silica nanoparticles, a cellulosic, a saccharide, a biopolymer, sodium alginate / alginic acid, and combinations thereof.

[0227] Illustrative embodiment 37. A method of producing an anti-fog and / or anti-frost optically transparent coating for a substrate, the method comprising the steps of: mixing an aqueous solution comprising a water-soluble polyvinyl alcohol with at least one of (a) or (b) to provide a mixture: an aqueous solution comprising at least one water-soluble, organic or inorganic chemical crosslinking agent; and / or a hydrolyzable metal alkoxide; applying the mixture to at least a portion of at least one surface of the substrate; and curing the mixture applied to the substrate to form the coating.

[0228] Illustrative embodiment 38. The method of Illustrative embodiment 37, wherein the aqueous solution comprising the water-soluble polyvinyl alcohol further comprises a water-soluble polyacrylic acid.

[0229] Illustrative embodiment 38a. The method of Illustrative embodiment 38, wherein polyvinyl alcohol and polyacrylic acid are present in a polyvinyl alcohokpolyacrylic acid ratio in a range of from about 5:0.5 to about 5:1.5 by weight.

[0230] Illustrative embodiment 39. The method of Illustrative embodiment 37 or 38, wherein the curing step occurs at ambient temperature and environment.

[0231] Illustrative embodiment 40. The method of any of Illustrative embodiments 37-39, wherein the curing step involves heating at least a portion of the mixture applied to the substrate to form the coating.

[0232] Illustrative embodiment 41. The method of Illustrative embodiment 40, wherein the mixture is heated to a temperature in a range of from about 100°C to about 190°C.

[0233] Illustrative embodiment 42. The method of any one of Illustrative embodiments 37-41, wherein the mixture is applied to the surface by a method selected from the group consisting of roll coating, spray coating, dip coating, slot die coating, or curtain coating.

[0234] Illustrative embodiment 43. The method of any one of Illustrative embodiments 37-42, wherein the coating is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength.

[0235] Illustrative embodiment 44. The method of any one of Illustrative embodiments 37-43, wherein the coating is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

[0236] Illustrative embodiment 45. The method of any one of Illustrative embodiments 37-44, wherein the at least one crosslinking agent is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloidalkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, and combinations thereof.

[0237] Illustrative embodiment 46. The method of any one of Illustrative embodiments 37-45, wherein the at least one crosslinking agent is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3- glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

[0238] Illustrative embodiment 46a. The method of Illustrative embodiment 46, wherein the at least one crosslinking agent comprises (3-glycidyloxypropyl)trimethoxysilane (3- GPTMS) and / or tetraethoxysilane (TEOS).

[0239] Illustrative embodiment 46b. The method of Illustrative embodiment 46 or 46a, wherein the at least one crosslinking agent comprises a PEG silane.

[0240] Illustrative embodiment 46c. The method of any of Illustrative embodiments 46- 46b, wherein the PEG silane comprises triethoxysilylpropoxy (polyethyleneoxy)dodecandoate.

[0241] Illustrative embodiment 46d. The method of any one of Illustrative embodiments 46-46c, wherein the at least one crosslinking agent of (2) comprises a Dipodal silane.

[0242] Illustrative embodiment 46e. The system of Illustrative embodiment 46d, wherein the Dipodal silane comprises 1,2-Bis(trimethoxysilyl)decane.

[0243] Illustrative embodiment 47. The method of any one of Illustrative embodiments 37-46e, wherein the at least one crosslinking agent is present in the coating at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

[0244] Illustrative embodiment 48. The method of any one of Illustrative embodiments 37-47, wherein the coating has a thickness in a range of from about 10 microns to about 200 nm.

[0245] Illustrative embodiment 49. The method of any one of Illustrative embodiments 37-48, wherein the surface of the article of manufacture to which the coating is applied is transparent, translucent, and / or reflective.

[0246] Illustrative embodiment 50. The method of any one of Illustrative embodiments 37-49, wherein the method is performed substantially in the absence of volatile organic compounds.

[0247] Illustrative embodiment 51. The method of any one of Illustrative embodiments 37-50, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

[0248] Illustrative embodiment 52. The method of any one of Illustrative embodiments 37-51, wherein the substrate forms a portion of an article of manufacture.

[0249] Illustrative embodiment 53. The method of any one of Illustrative embodiments 37-52, wherein the mixture further comprises at least one surfactant.

[0250] Illustrative embodiment 53a. The method of Illustrative embodiment 53, wherein the at least one surfactant is a polyoxyethylene ether nonionic fluorosurfactant.

[0251] Illustrative embodiment 54. The method of any one of Illustrative embodiments 37-53a, wherein the mixture further comprises at least one coupling agent.

[0252] Illustrative embodiment 54a. The method of Illustrative embodiment 54, wherein the at least one coupling agent comprises (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS) and / or tetraethoxysilane (TEOS).

[0253] Illustrative embodiment 54b. The method of any one of Illustrative embodiments 37-54a, wherein the mixture further comprises at least one additional component selected from the group consisting of a slip additive, fumed silica, silica nanoparticles, organically modified silica nanoparticles, a cellulosic, a saccharide, a biopolymer, sodium a Igi nate / algi nic acid, and combinations thereof.

[0254] Illustrative embodiment 55. The method of any one of Illustrative embodiments 37-54a, further comprising the step of adjusting a pH of the mixture to a pH in a range of from about 3 to about 4 prior to applying the mixture to at least a portion of at least one surface of the substrate.

[0255] Thus, in accordance with the present disclosure, there have been provided composition, assemblies, and kits, as well as methods of producing and using same, which fully satisfy the objectives and advantages set forth hereinabove. Although the present disclosure has been described in conjunction with the specific drawings, experimentation, results, and language set forth hereinabove, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it isintended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the present disclosure.

Claims

CLAIMS1. A system for producing an anti-fog and / or anti-frost optically transparent coating, the system comprising:(1) an aqueous solution comprising a water-soluble polyvinyl alcohol; and(2) at least one of:(a) an aqueous solution comprising at least one water-soluble, organic or inorganic chemical crosslinking agent; and / or(b) a hydrolysable metal-alkoxide.

2. The system of claim 1, wherein (1) further comprises a water-soluble polyacrylic acid.

3. The system of claim 2, wherein (1) contains a polyvinyl alcohol: polyacrylic acid ratio in a range of from about 5:0.5 to about 5:1.5 by weight.

4. The system of claim 1, wherein the at least one crosslinking agent of (2) is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, a silane, and combinations thereof.

5. The system of claim 1, wherein the at least one crosslinking agent of (2) is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

6. The system of claim 1, wherein the at least one crosslinking agent is present in (2) at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

7. The system of claim 1, further comprising instructions for combining (1) and (2) to produce the anti-fog and / or anti-frost coating on a substrate.

8. The system of claim 1, wherein the system is substantially free of volatile organic compounds.

9. The system of claim 1, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

10. The system of claim 1, further comprising at least one surfactant.

11. The system of any one of claims l-10a, further comprising at least one coupling agent.

12. An anti-fog and / or anti-frost coating composition, the composition comprising: polyvinyl alcohol; and at least one organic or inorganic chemical crosslinking agent; and wherein the coating composition is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength.

13. The coating composition of claim 12, further comprising polyacrylic acid.

14. The coating composition of claim 12, wherein the coating composition is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

15. The coating composition of claim 12, wherein the at least one crosslinking agent is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, and combinations thereof.

16. The coating composition of claim 12, wherein the at least one crosslinking agent is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane(TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

17. The coating composition of claim 12, wherein the at least one crosslinking agent is present in the coating composition at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

18. The coating composition of claim 12, further defined as a film for application to at least a portion of at least one surface of an article of manufacture.

19. The coating composition of claim 18, wherein the film has a thickness in a range of from about 10 microns to about 200 nm.

20. The coating composition of claim 12, wherein the coating composition is substantially free of volatile organic compounds.

21. The coating composition of claim 12, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

22. The coating composition of claim 12, further comprising at least one surfactant.

23. The coating composition of claim 12, further comprising at least one coupling agent.

24. An assembly, comprising: a substrate having at least one surface; and an anti-fog and / or anti-frost optically transparent coating disposed on at least a portion of the at least one surface of the substrate, wherein the coating comprises: polyvinyl alcohol; and at least one organic or inorganic chemical crosslinking agent; and wherein the coating is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength.

25. The assembly of claim 24, wherein the coating further comprises polyacrylic acid.

26. The assembly of claim 24, wherein the coating is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

27. The assembly of claim 24, wherein the at least one crosslinking agent is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, and combinations thereof.

28. The assembly of claim 24, wherein the at least one crosslinking agent is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

29. The assembly of claim 24, wherein the at least one crosslinking agent is present in the coating at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

30. The assembly of claim 24, wherein the coating has a thickness in a range of from about 10 microns to about 200 nm.

31. The assembly of claim 24, wherein the surface of the substrate to which the coating is applied is transparent, translucent, and / or reflective.

32. The assembly of claim 24, wherein the coating is substantially free of volatile organic compounds.

33. The assembly of claim 24, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

34. The assembly of claim 24, wherein the coating further comprises at least one surfactant.

35. The assembly of claim 24, wherein the coating further comprises at least one coupling agent.

36. A method of producing an anti-fog and / or anti-frost optically transparent coating for a substrate, the method comprising the steps of: mixing an aqueous solution comprising a water-soluble polyvinyl alcohol with at least one of (a) or (b) to provide a mixture:(a) an aqueous solution comprising at least one water-soluble, organic or inorganic chemical crosslinking agent; and / or(b) a hydrolyzable metal alkoxide; applying the mixture to at least a portion of at least one surface of the substrate; and curing the mixture applied to the substrate to form the coating.

37. The method of claim 36, wherein the aqueous solution comprising the water-soluble polyvinyl alcohol further comprises a water-soluble polyacrylic acid.

38. The method of claim 36, wherein the curing step occurs at ambient temperature and environment.

39. The method of claim 36, wherein the curing step involves heating at least a portion of the mixture applied to the substrate to form the coating.

40. The method of claim 39, wherein the mixture is heated to a temperature in a range of from about 100°C to about 190°C.

41. The method of claim 36, wherein the mixture is applied to the surface by a method selected from the group consisting of roll coating, spray coating, dip coating, slot die coating, or curtain coating.

42. The method of claim 36, wherein the coating is substantially optically transparent and has a transmission loss of less than about 1% at 550 nm wavelength.

43. The method of claim 36, wherein the coating is substantially water and abrasion resistant according to EN-1096 for greater than about 500 cycles.

44. The method of claim 36, wherein the at least one crosslinking agent is selected from the group consisting of a di- or poly acrylic acid, a di- or poly carboxylic acid, an aldehyde, a metal alkoxide, a metalloid alkoxide, a polyisocyanate, a polyurethane, an epichlorohydrin, a metal nanoparticle, a metalloid nanoparticle, and combinations thereof.

45. The method of claim 36, wherein the at least one crosslinking agent is selected from the group consisting of glyoxal, glutaraldehyde, formaldehyde, a silicon alkoxide, a titanium alkoxide, a zirconium alkoxide, an aluminum alkoxide, a vanadium alkoxide, a niobium alkoxide, a tantalum alkoxide, boric acid, potassium tert-butoxide, tetra-methyl orthosilicate, (3-glycidyloxypropyl)trimethoxysilane (3-GPTMS), tetraethoxysilane (TEOS), a PEG silane, a Dipodal silane, maleic acid, citric acid, and combinations thereof.

46. The method of claim 36, wherein the at least one crosslinking agent is present in the coating at a concentration in a range of from about 0.1% to about 40% based on the total weight of solids.

47. The method of claim 36, wherein the coating has a thickness in a range of from about 10 microns to about 200 nm.

48. The method of claim 36, wherein the surface of the article of manufacture to which the coating is applied is transparent, translucent, and / or reflective.

49. The method of claim 36, wherein the method is performed substantially in the absence of volatile organic compounds.

50. The method of claim 36, wherein the polyvinyl alcohol has a degree of hydrolysis in a range of from about 55% to about 100%.

51. The method of claim 36, wherein the substrate forms a portion of an article of manufacture.

52. The method of claim 36, wherein the mixture further comprises at least one surfactant.

53. The method of claim 36, further comprising the step of adjusting a pH of the mixture to a pH in a range of from about 3 to about 4 prior to applying the mixture to at least a portion of at least one surface of the substrate.

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