JP5343133B2 - Undercoating layer that improves topcoat functionality - Google Patents

Abstract

A coated article includes a substrate and a first coating formed over at least a portion of the substrate. The first coating includes a mixture of oxides including oxides of at least two of P, Si, Ti, Al and Zr. A functional coating is formed over at least a portion of the first coating. The functional coating is selected from an electrically conductive coating and a photoactive coating. In one embodiment, the functional coating includes fluorine doped tin oxide. In another embodiment, the functional coating includes titania.

Description

  This application claims the priority of U.S. Patent Application No. 12/273617, U.S. Patent Application No. 12/273623, and U.S. Patent Application No. 12/2733641, all filed on November 19, 2008, All of these three applications are hereby incorporated by reference in their entirety.

  The present invention relates generally to coated articles, particularly multilayer coated articles having a functional topcoat and at least one undercoating layer.

  Articles having a multilayer coating are used in a variety of applications. One example is in the field of thin film solar cells. A typical solar cell includes a substrate having a transparent conductive film (first electrode), for example, a glass plate. A semiconductor film having a photoelectric conversion material is deposited on the transparent conductive film. The battery includes another substrate having a transparent conductive film (second electrode). An electrolyte can be encapsulated between the two electrodes. When the photoelectric conversion material adsorbed on the semiconductor film is irradiated, electrons generated by the irradiation move through the semiconductor film into one of the transparent conductive films. For example, electrons can travel through the first electrode, through the electrical lead, and to another electrode. In a solar cell, it is important for photoelectric conversion efficiency that electrons move to another electrode through the first conductive film as quickly as possible. That is, it is desirable if the surface resistance of the transparent conductive film is low. If the electrons do not move fast, recombination between the electrons and the photoelectric conversion material (usually referred to as “reverse current” or “reverse current”) can occur. It is also desirable if the conductive film is very transparent so as to allow the maximum amount of solar radiation to travel to the photoelectric conversion material. Accordingly, it may be desirable to provide a coated article for a solar cell that increases the flow of electrons through the transparent conductive film. That is, a transparent conductive film having a low surface resistance.

  Another example of a field that utilizes coated articles is the field of photocatalytic articles. In order to obtain coated articles with self-cleaning properties, it is known to apply a photocatalytic coating, such as titania, on the substrate. Upon exposure to certain electromagnetic radiation, such as ultraviolet light, the photocatalytic coating interacts with the organic contaminant at the coating surface to degrade or decompose the organic contaminant. However, conventional photocatalytic articles have a relatively large visible light reflectivity and as a result may be unsuitable for use in some architectural applications. Furthermore, conventional photocatalytic coatings can be degraded through what is commonly referred to as “sodium ion poisoning” caused by sodium ions diffusing from the underlying glass substrate to the photocatalytic coating. In addition, conventional photocatalytic coatings tend to exhibit irrideence effects that detract from the aesthetic appearance of the coated article.

  Therefore, it sits between the substrate and a functional topcoat (eg, but not limited to a conductive photovoltaic transparent conductive coating or photocatalytic coating) and only serves as a barrier for sodium ion diffusion. It would be desirable to provide a coated article having an undercoating layer that also improves the performance of the coated article. For example, performance can be improved by reducing the reflectance of the coated article and / or providing color suppression to the article and / or enhancing the functionality of the topcoat. For example, in photovoltaic applications, the undercoating layer can reduce the surface resistance of the topcoat (eg, transparent conductive layer) to increase electron flow. In photocatalytic applications, the undercoating layer can increase the photocatalytic activity of the photocatalytic coating.

  The coated article includes a substrate and a first coating formed on at least a portion of the substrate. The first coating includes at least two oxides of P, Si, Ti, Al, and Zr. A functional coating is formed on at least a portion of the first coating. In one non-limiting embodiment, the first coating includes at least Ti and Si oxides. In another non-limiting embodiment, the first coating comprises at least Ti, Si and P oxides. In yet another non-limiting embodiment, the first coating includes at least oxides of Ti, Si and Al. Another embodiment may include any combination of two or more of these materials. Examples of functional coatings include, but are not limited to, photoactive coatings (eg, photocatalytic coatings and / or photohydrophilic coatings), and conductive coatings. The functional coating can be applied over the first coating having any combination of the components.

  Another coated article includes a glass substrate and a first coating formed on at least a portion of the substrate. The first coating includes at least two oxides of P, Si, Ti, Al, and Zr. A functional coating is formed on at least a portion of the first coating. The functional coating is selected from titania and fluorine doped tin oxide.

  The method of manufacturing a coated article includes the steps of providing a glass substrate; forming a first coating on at least a portion of the glass substrate by directing the first coating composition to the glass substrate by CVD. The first coating composition includes a silica accelerator comprising a silica precursor, a titania precursor, and at least one accelerator material having at least one of P, Al, and Zr. Forming a functional coating on at least a portion of the first coating by directing the second coating composition to the glass substrate by CVD, wherein the second coating composition is doped with fluorine. Tin oxide precursor composition or titania precursor assembly Comprising the step of including things.

  The further coated article includes a substrate and a first coating formed on at least a portion of the substrate. The first coating includes a mixture of oxides including at least two oxides of P, Si, Ti, Al, and Zr. A conductive coating is formed on at least a portion of the first coating. The conductive coating is made of Zn, Fe, Mn, Al, Ce, Sn, Sb, Hf, Zr, Ni, Zn, Bi, Ti, Co, Cr, Si or In, or an alloy of two or more of these materials. Contains one or more oxides.

  A method for reducing the surface resistance of a conductive coating includes: providing a substrate; forming a first coating on at least a portion of the substrate, wherein the first coating comprises P, Si, Ti, Al, and Including at least two oxides of Zr; and forming a conductive coating on at least a portion of the first coating.

  A method for reducing haze and / or increasing visible light transmission of a coated article comprises: providing a substrate; forming a first coating on at least a portion of the substrate, the first coating comprising: The coating includes at least two oxides of P, Si, Ti, Al, and Zr; and forming a functional coating on at least a portion of the first coating.

  The further coated article includes a substrate and a first coating formed on at least a portion of the substrate. The first coating includes a mixture of oxides including at least two oxides of P, Si, Ti, Al, and Zr. A photoactive coating is formed on at least a portion of the first coating.

  The photoactive article includes a glass substrate and a first coating formed on at least a portion of the substrate. The first coating comprises a mixture of silica, titania and alumina. A photoactive functional coating comprising titania is formed on at least a portion of the first coating.

  A method for improving the photocatalytic activity of a photoactive coating comprises: providing a substrate; forming a first coating on at least a portion of the substrate, wherein the first coating comprises P, Si, Ti, Al, and Including at least two oxides of Zr; and forming a photoactive coating on at least a portion of the first coating.

  The method for producing a photoactive article includes the steps of providing a glass substrate; forming a first coating on at least a portion of the glass substrate by directing the first coating composition to the glass substrate by CVD; At least a portion of the first coating by directing the second coating composition to the glass substrate by CVD, and wherein the first coating composition comprises tetraethylorthosilicate, titanium isopropoxide, and dimethylaluminum isopropoxide; Forming a photoactive coating thereon, wherein the photoactive coating comprises titania.

  A full understanding of the invention will be gained from the following description, when considered in conjunction with the accompanying drawings.

1 is a side cross-sectional view (not drawn to scale) of a coated article that includes features of the present invention. FIG. Surface resistance vs. for fluorine doped tin oxide coatings formed directly on glass or on the undercoating of the present invention. It is a graph of [Sn]. Percent transmittance vs. for fluorine doped tin oxide coatings formed directly on glass or on the undercoating of the present invention. It is a graph of a wavelength. Reflectance vs. for the coated article of Example 5. It is a graph of the thickness of titania. 7 is a graph of color change for the coated article of Example 6.

  As used herein, space or direction terms, such as “left”, “right”, “inside”, “outside”, “upper”, “lower”, etc., are shown in the figures. As such, it is relevant to the present invention. However, it is to be understood that the present invention can take a variety of alternative orientations, and thus such terms should not be considered limiting. Furthermore, as used in this document, all numerical values used in the specification and claims, such as dimensions, physical properties, processing parameters, component amounts, reaction conditions, etc., are in all cases the term “ It should be understood that it is modified by “about”. Accordingly, unless stated otherwise, the numerical values set forth in the following specification and claims may vary depending on the desired properties sought to be obtained by the present invention. At least, and not as an attempt to limit the applicability of the doctrine of equivalents to the claims, each number is at least interpreted by taking into account the reported significant figures and applying normal rounding techniques. It should be. Moreover, all ranges disclosed herein are to be understood to encompass the beginning and ending values of those ranges and any and all subranges that are part of them. . For example, a range referred to as “1 to 10” is any sub-range between the minimum value of 1 and the maximum value of 10 (and includes these boundary values), ie a minimum value of 1 or All subranges beginning with a value greater than and ending with a maximum value of 10 or less should be considered to include, for example, 1 to 3.3, 4.7 to 7.5, 5.5 to 10, and the like. Further, as used herein, the terms “formed on”, “deposited on (evaporated)”, or “provided on” form a deposited (evaporated) on a surface. ) Or provided, but not necessarily in direct contact with the surface. For example, a coating layer “formed on” a substrate does not exclude the presence of one or more other coating layers or films of the same or different composition located between the formed coating layer and the substrate. . As used herein, the term “polymer” or “polymeric” includes oligomers, homopolymers, copolymers, and terpolymers, eg, polymers produced from two or more monomers or polymers. The term “visible region” or “visible light” refers to electromagnetic radiation having a wavelength in the range of 380 nm to 760 nm. The term “infrared region” or “infrared” refers to electromagnetic radiation having a wavelength in the range of greater than 760 nm to 100,000 nm. The term “ultraviolet region” or “ultraviolet light” means electromagnetic energy having a wavelength in the range of 300 nm to less than 380 nm. The term “microwave region” or “microwave” refers to electromagnetic radiation having a frequency in the range of 300 megahertz to 300 gigahertz. Moreover, all documents referred to herein, such as, but not limited to, issued patents and patent applications, are to be considered “incorporated by reference” in their entirety. In the following description, the refractive index value is at a reference wavelength of 550 nanometers (nm). The term “membrane” refers to the portion of the coating having the desired or selected composition. A “layer” includes one or more “membranes”. A “coating” or “coating stack” includes one or more “layers”.

  A coated article 10 that includes features of the present invention is illustrated in FIG. Article 10 includes a substrate 12 having at least one major surface. The first coating (undercoating layer) 14 of the present invention is formed on at least a part of the main surface. The second coating (functional coating) 16 is formed on at least a part of the first coating 14. Although specific exemplary embodiments will now be described, one or more features of the present invention included in these embodiments may be combined with one or more embodiments of other embodiments, And it should be understood that the invention is not limited to the specific exemplary embodiments described below.

  In a broad implementation of the invention, the substrate 12 includes any desired material having any desired characteristics. For example, the substrate 12 can be transparent, translucent, or opaque to visible light. By “transparent” is meant having a visible light transmission greater than 0% and up to 100%. Alternatively, the substrate 12 can be translucent or opaque. “Translucent” means that electromagnetic energy (eg, visible light) is transmitted, but this energy is diffused so that an object on the other side of the viewer cannot be seen clearly. By “opaque” is meant having a visible light transmission of 0%. Examples of suitable materials include, but are not limited to, plastic substrates (eg, acrylic polymers such as polyacrylates; polyalkyl methacrylates such as polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, etc .; polyurethanes; polycarbonates; Polyalkyl terephthalates, such as polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate, etc .; polysiloxane-containing polymers; or copolymers of any monomer to produce them, or mixtures thereof); metal substrates, such as these But not limited to: galvanized steel, stainless steel, and aluminum; ceramic substrate; tile substrate; glass substrate; It is included any mixture or combination of the above. For example, the substrate can include conventional soda lime silicate glass, borosilicate glass, or lead glass. The glass can be a transparent glass. By “transparent glass” is meant a glass that is not lightly colored or uncolored. Alternatively, the glass can be lightly colored or differently colored glass. The glass can be annealed or heat treated glass. As used herein, the term “heat treated” means tempered or at least partially tempered. The glass can be of any type, for example, normal float glass, and can have any optical properties such as visible transmittance, ultraviolet transmittance, infrared transmittance, and / or total sun It may be of any composition having any value of energy transmission. By “float glass” is meant glass formed by the usual float process in which molten glass is placed on a molten metal bath and controlled to cool to produce a float glass ribbon. While not limiting to the present invention, examples of glasses suitable for the substrate include: U.S. Pat. No. 4,746,347, U.S. Pat. No. 4,792,536, U.S. Pat. No. 5,030,593, U.S. Pat. No. 5,030,594, U.S. Pat. And U.S. Pat. No. 5,393,593. Non-limiting examples of glasses that can be used in the practice of the present invention include Solargreen®, Solextra®, GL-20®, GL-35®, Solarbronze®, Starphire (R), Solarfire (R), Solarfire PV (R) and Solargray (R) glass, all of which are available from PPG Industries Inc. (Pittsburgh, Pennsylvania). The glass may have a smooth surface or, alternatively, a rough or textured surface. In a non-limiting embodiment, the glass surface can have a surface roughness (RMS) in the range of 100 nm to 5 mm.

  The substrate 12 may be of any desired dimension (eg, length, width, shape, or thickness). For example, the substrate 12 may be planar or curved, or may have both planar and curved portions. In one non-limiting embodiment, the substrate 12 can have a thickness in the range of 1 mm to 10 mm (eg, 1 mm to 5 mm, eg 2 mm to 4 mm, eg 3 mm to 4 mm).

  In one non-limiting embodiment, the substrate 12 can have a high visible light transmission at a reference wavelength of 550 nanometers (nm). By “large visible light transmittance” is meant a visible light transmittance at 550 nm of 85% or more (eg, 87% or more, eg, 90% or more, eg, 91% or more, eg, 92% or more).

  The first coating (undercoating layer) 14 provides various performance advantages to the coated article 10, as described in more detail below. In one non-limiting embodiment of the present invention, the first coating 14 can be a uniform coating. By “uniform coating” is meant a coating in which the material is distributed evenly throughout the coating. Alternatively, the first coating 14 can include multiple coating layers or films (eg, two or more separate coating films). Further alternatively, the first coating 14 can be a gradient layer. By “gradient layer” is meant a layer comprising two or more components whose concentration of components changes continuously (or stepwise) as the distance from the substrate changes.

  In one non-limiting embodiment, the first coating 14 comprises a mixture of two or more oxides selected from silicon, titanium, aluminum, zirconium, and / or phosphorus oxides. The oxide can be in any desired ratio. In one non-limiting embodiment, the first coating 14 comprises a mixture of silica and titania, the silica is present in the range of 0.1 weight percent (wt%) to 99.9 wt%, and the titania is 99.99 wt. It exists in the range of 9 wt% to 0.1 wt%. The first coating 14 can be a uniform coating. Alternatively, the first coating 14 may be a gradient coating in which the relative proportions of silica and titania vary throughout the coating. For example, the first coating 14 may be primarily silica in the portion adjacent to the substrate surface and primarily titania in the outer portion of the first coating 14.

  As explained above, the first coating 14 may comprise a mixture of at least two oxides having an element selected from silicon, titanium, aluminum, zirconium and / or phosphorus. Such mixtures include, but are not limited to, titania and phosphorus oxide; silica and alumina; titania and alumina; silica and phosphorus oxide; titania and phosphorus oxide; silica and zirconia; titania and zirconia; alumina and zirconia; Phosphorus oxide; zirconia and phosphorus oxide; or any combination of the above materials. The relative proportions of oxides can be any amount desired (eg, 0.1 wt% to 99.9 wt% of one material and 99.9 wt% to 0.1 wt% of other materials).

  Furthermore, the first coating 14 is a mixture of at least three oxides, such as, but not limited to, three or more oxides having an element selected from silicon, titanium, aluminum, zirconium and / or phosphorus. Can be included. Examples include, but are not limited to, silica, titania and phosphorus oxide; silica, titania and alumina; and mixtures comprising silica, titania and zirconia. In one non-limiting embodiment, the first coating 14 includes silica and titania with at least one other oxide selected from alumina, zirconia, and phosphorus oxide. The relative proportions of oxides can be any amount desired (eg, 0.1 wt% to 99.9 wt% of one material, 99.9 wt% to 0.1 wt% of a second material, and 0. 99.9 wt% third material from 1 wt%).

  The particular first coating 14 of the present invention comprises a mixture of silica, titania and phosphorus oxide. Silica can be present in the range of 30 volume percent (vol%) to 80 vol%. Titania can be present in the range of 5 vol% to 69 vol%. Phosphorus oxide can be present in the range of 1 vol% to 15 vol%.

  The first coating 14 may have any desired thickness (for example, but not limited to, 10 nm to 120 nm, such as 30 nm to 80 nm, such as 40 nm to 80 nm, such as 30 nm to 70 nm).

  The second coating (topcoat) 16 includes a functional coating. Examples of functional coatings useful in the present invention include, but are not limited to, conductive coatings, solar control coatings, low emissivity coatings, and photoactive coatings.

  In one non-limiting embodiment, the second coating 16 includes at least one conductive oxide layer, eg, a doped oxide layer. For example, the second coating 16 may include one or more oxide materials such as, but not limited to, Zn, Fe, Mn, Al, Ce, Sn, Sb, Hf, Zr, Ni, Zn, Bi, One or more of one or more oxides of Ti, Co, Cr, Si or In, or two or more alloys of these materials may be included. The second coating 16 may also include one or more dopant materials, such as, but not limited to, F, In, Al, and / or Sb. In one non-limiting embodiment, the second coating 16 is tin oxide doped with fluorine, the fluorine being less than 20 wt% (eg, less than 15 wt%, such as less than 13 wt%) relative to the total weight of the precursor material. Present in the coating precursor material in an amount of, for example, less than 10 wt. The second coating 16 can be amorphous, crystalline, or at least partially crystalline.

  In one non-limiting embodiment, the second coating 16 has a thickness greater than 200 nm (eg, greater than 250 nm, such as greater than 350 nm, such as greater than 380 nm, such as greater than 400 nm, such as greater than 420 nm), fluorine. Contains doped tin oxide. In one non-limiting embodiment, the thickness is in the range of 350 nm to 420 nm.

  The undercoating layer 14 of the present invention is less than 15 ohms / square (Ω / □) (eg, less than 14 Ω / □, such as less than 13.5 Ω / □, such as less than 13 Ω / □, such as less than 12 Ω / □, such as 11 Ω / □. A topcoat 16 (eg, fluorine-doped tin oxide) having a surface resistance of less than □, eg, less than 10 Ω / □ is provided.

In another non-limiting embodiment, the second coating 16 can be a photoactive coating. The term “photoactive” or “by photoactivity” refers to the photoinduced generation of hole-electron pairs when illuminated by a particular frequency of radiation, eg, ultraviolet (“UV”) light. The photoactive coating can be photocatalytic, photoactive hydrophilic, or both. By “photocatalyst”, coatings that are self-cleaning, ie, coatings that interact with organic contaminants on the coating surface upon exposure to certain electromagnetic radiation, eg UV, to degrade or degrade organic contaminants Means. By “hydrophilic due to photoactivity” is meant a coating in which the contact angle of a water droplet on the coating decreases over time as a result of exposing the coating to electromagnetic radiation in the light absorption band of the material. For example, after 60 minutes exposure to radiation in the light absorption band of the material having an intensity of 24 W / m ² at the coating surface, the contact angle drops to a value of less than 15 ° (eg less than 10 °) For example, it can drop below 5 °. Even if photoactive, the coating does not necessarily have to be photocatalytic as much as it is self-cleaning, i.e. organic materials such as dirt on the coating surface for a reasonable or economically effective period. It may not be photocatalytic enough to decompose. For example, the photocatalytic activity is less than 4 × 10 ⁻³ / centimeter · minute (cm ⁻¹ min ⁻¹ ) (for example, less than 3 × 10 ⁻³ cm ⁻¹ min ⁻¹ , for example, 2 × 10 ⁻³ cm ⁻¹ min Less than ⁻¹ , for example less than 1 × 10 ⁻³ cm ⁻¹ min ⁻¹ ).

  The photoactive coating comprises at least one photoactive coating material and optionally at least one additive designed to effect a change in the photoactivity of the coating relative to the photoactivity of the coating without the dopant material. Or a dopant. The photoactive coating material includes at least one oxide, such as, but not limited to, one or more oxides or oxide semiconductors (eg, titanium oxide, silicon oxide, aluminum oxide, iron oxide, silver oxide, Cobalt oxide, chromium oxide, copper oxide, tungsten oxide, zinc oxide, oxide (zinc / tin), strontium titanate, and mixtures thereof). Oxides include elemental oxides, superoxides or suboxides. The oxide can be crystalline or at least partially crystalline. In one exemplary coating of the present invention, the photoactive coating material is titanium dioxide (titania). Titanium dioxide exists in an amorphous state and in three crystal forms: anatase, rutile and brookite crystal forms. Anatase phase titanium dioxide is particularly useful because it exhibits strong photoactivity and at the same time has excellent resistance to chemical attack and excellent physical durability. However, a combination of a rutile phase or anatase and / or rutile phase with a brookite and / or amorphous phase is also acceptable in the present invention.

  Examples of dopants useful for the present invention for photoactive coatings include, but are not limited to, chromium (Cr), vanadium (V), manganese (Mn), copper (Cu), iron (Fe), magnesium (Mg), scandium (Sc), yttrium (Y), niobium (Nb), molybdenum (Mo) ruthenium (Ru), tungsten (W), silver (Ag), lead (Pb), nickel (Ni), rhenium ( Re), tin (Sn), and / or one or more of any mixture or combination thereof, either in elemental or ionic state.

  In one non-limiting embodiment, the second coating 16 is greater than 10 nm (e.g. greater than 20 nm, e.g. greater than 30 nm, e.g. greater than 40 nm, e.g. greater than 50 nm, e.g. greater than 60 nm, e.g. greater than 70 nm, e.g. greater than 80 nm. Titania with a thickness greater than, eg greater than 90 nm, eg greater than 100 nm, eg in the range of 10 nm to 150 nm.

  In one non-limiting embodiment, the first coating 14 of the present invention is less than 23% (eg, less than 20%, such as less than 19%, such as less than 18%, such as less than 17%, such as less than 16%, such as 15%. An article 10 having a titania second coating 16 having a reflectivity in the visible region of less than, such as less than 14%, such as less than 12%, such as less than 11%, such as less than 10%.

  The first coating 14 and / or the second coating 16 may be applied to at least a portion of the substrate 12 in any conventional manner, such as, but not limited to, spray pyrolysis, chemical vapor deposition (CVD), or magnetron. It can be formed by vacuum deposition (MSVD) by sputtering. In spray pyrolysis, an organic or metal-containing precursor comprising one or more oxide precursor materials (eg, titania and / or silica and / or alumina and / or phosphorus oxide and / or zirconia precursor material). The composition is held in suspension, for example in aqueous or non-aqueous solution, and directed to the surface of the substrate, while the substrate causes degradation of the precursor composition and forms a coating on the substrate. The temperature is high enough. The composition may include one or more dopant materials. In the CVD method, the precursor composition is held in a carrier gas, such as nitrogen gas, and directed to a heated substrate. In the MSVD method, one or more metal-containing cathode targets are sputtered under reduced pressure in an inert or oxygen-containing atmosphere to deposit a sputter coating on the substrate. The substrate can be heated during or after the coating to cause crystallization of the coating by sputtering to form the coating.

  In one non-limiting implementation of the present invention, one or more CVD coating equipment can be used at one or more locations in a typical float glass ribbon manufacturing process. For example, a CVD coating device can be used when a float glass ribbon is moving an annealing rare after it leaves the tin bath and before it enters the annealing rare when it is moving the tin bath. Or it can be used after leaving the annealing rare. Since CVD methods can coat moving float glass ribbons and can withstand the harsh environments associated with producing float glass ribbons, CVD methods deposit coatings on float glass ribbons in molten tin baths. Especially well suited for. US Pat. No. 4,853,257, US Pat. No. 4,971,843, US Pat. No. 5,536,718, US Pat. No. 5,464,657, US Pat. No. 5,714,199, and US Pat. No. 5,599,387 are designed to coat float glass ribbons in a molten tin bath. Describes a CVD coating apparatus and method that can be used to practice the present invention.

  In one non-limiting embodiment, one or more CVD coating devices can be placed over the molten tin pool in a tin bath. As the float glass ribbon moves through the tin bath, the vaporized precursor composition can be added to the carrier gas and directed onto the upper surface of the ribbon. The precursor composition decomposes to form a coating (eg, first coating 14 and / or second coating 16) on the ribbon. In one non-limiting embodiment, the coating composition has a ribbon temperature of less than 1300 ° F. (704 ° C.), such as less than 1250 ° F. (677 ° C.), such as less than 1200 ° F. (649 ° C.), such as 1190 ° F. At a position that is less than (643 ° C.), such as less than 1150 ° F. (621 ° C.), such as less than 1130 ° F. (610 ° C.), such as in the range of 1190 ° F. to 1200 ° F. (643 ° C. to 649 ° C.). It is deposited on. This is particularly useful for depositing a second coating 16 (eg, fluorine-doped tin oxide) having a low surface resistance, since the lower the deposition temperature, the lower the resulting surface resistance.

  For example, to form a first coating 14 that includes silica and titania, the composition includes both a silica precursor and a titania precursor. One non-limiting example of a silica precursor is tetraethylorthosilicate (TEOS).

  Examples of titania precursors include, but are not limited to, titanium oxides, suboxides, or superoxides. In one embodiment, the titania precursor material includes one or more titanium alkoxides, such as, but not limited to, titanium methoxide, ethoxide, propoxide, butoxide, etc .; or isomers thereof, such as titanium Isopropoxide, tetraethoxide and the like are included. Exemplary precursor materials suitable for the practice of the present invention include, but are not limited to, tetraisopropyl titanate (TPT). Alternatively, the titania precursor material may be titanium tetrachloride. Examples of alumina precursors include, but are not limited to, dimethylaluminum isopropoxide (DMAP) and aluminum tri-sec-butoxide (ATSB). In one non-limiting embodiment, dimethylaluminum isopropoxide can be prepared by mixing trimethylaluminum and aluminum isopropoxide in a 2: 1 molar ratio in an inert atmosphere at room temperature. Examples of phosphorus oxide precursors include, but are not limited to, triethyl phosphite. Examples of zirconia precursors include, but are not limited to, zirconium alkoxides.

  The first coating 14 having a combination of silica and titania provides advantages over previous oxide combinations. For example, a combination of a low refractive index material such as silica (550 nm, refractive index 1.5) and a high refractive index material such as titania (550 nm, 2.4 refractive index) allows silica and titania. By changing the amount of the first coating 14, the refractive index of the first coating 14 is changed between these two extreme values. This is particularly useful for obtaining a first coating 14 that has coloring or iridescence inhibiting properties.

  However, the deposition rate of titania is usually much faster than that of silica. Under normal volume conditions, this limits the amount of silica to about 50 wt% or less, and in turn this limits the lower range of refractive index of the resulting silica / titania coating. Thus, a dopant material can be added to the silica and titania composition to increase the deposition rate of silica. Since the dopant forms part of the resulting oxide mixture, it can be selected to provide improved performance characteristics to the resulting coating. Examples of dopants useful in the practice of the present invention include, but are not limited to, materials comprising one or more of phosphorus, aluminum, and zirconium, so as to produce oxides of these materials in the resulting coating. . An example of a phosphorus oxide precursor material includes triethyl phosphite. Examples of alumina precursor materials include aluminum trisec butoxide (ATSB) and dimethylaluminum isopropoxide (DMAP). Examples of the zirconia precursor include zirconium alkoxide.

(Example 1)
This example illustrates the use of the undercoating layer of the present invention as a color suppression layer for a titania topcoat. The undercoating layer was a combination of silica, titania and phosphorus oxide.

The undercoating layer was deposited on the glass substrate by chemical vapor deposition using a laboratory coating apparatus. A titania coating was then deposited on the undercoating. Table 1 shows the coating composition (composition and thickness) of Samples 1-4. The undercoating comprises three undercoating films: a first undercoating film on the glass substrate, a second undercoating film on the first undercoating film, and a third undercoating film on the second undercoating film. Deposited as a multi-layer with a coating film. The multi-layer configuration simulates a graded undercoating layer.

Table 2 shows the reflected color performance data for Samples 1-4 and comparative samples (glass sheets coated with titania without an undercoating layer). Color data are reported ⁱⁿ D65, 10 0 Observer, the coated side of the substrate, using a conventional TFCalc (TM) software was modeled.

In this example, the presence of the undercoating layer generally results in a ^* being smaller (more negative) and b ^* being larger (more positive) compared to an article without the undercoating layer.

(Example 2)
This example illustrates the use of the undercoating layer of the present invention to improve the photoactivity of the titania topcoat. The undercoating layer contained silica, titania and phosphorus oxide.

Both the undercoating layer and the topcoat (titania) were formed by chemical vapor deposition. The precursor of phosphorus oxide was triethyl phosphite (TPE). The silica precursor was tetraethylorthosilicate (TEOS). The titania precursor was tetraisopropyl titanate (TPT) in both the undercoat layer and the topcoat. Table 3 shows the deposition parameters for Samples 5-9.

Table 4 shows the layer thickness of Samples 5-9.

Table 5 shows the results of the normal stearic acid test for Samples 5-9. The stearic acid test is described in US Pat. No. 6,027,766 (incorporated herein by reference). As can be seen, the article with the undercoating layer of the present invention had a higher photocatalytic activity than the article without the undercoating layer (Sample 9).

(Example 3)
This example illustrates the use of the undercoating layer of the present invention to reduce the surface resistance of a fluorine doped tin oxide topcoat.

  The undercoating layer was a silica, titania, phosphorous oxide undercoat deposited by CVD. The precursors used were TEOS (silica), TPT (titania), and TEP (phosphorus oxide). Fluorine-doped tin oxide topcoats of varying thickness were deposited on the undercoating layer and also on uncoated glass (as a comparative sample). Both coatings were obtained from Electronic Design To Market, Inc. Measured by a commercially available R-Chek + 4 point meter and compared by surface resistance. Although the amount of [Sn] was determined by X-ray fluorescence, the amount of [Sn] corresponds to the thickness of the tin oxide coating doped with fluorine. FIG. 2 shows that the surface resistance of the fluorine-doped tin oxide coating on the undercoating layer of the present invention was on average 1 to 3 ohms / square lower than the same thickness of fluorine-doped tin oxide coating on the glass. . In FIG. 2, white squares and broken lines are for fluorine-doped tin oxide on glass. Black circles and solid lines are for the fluorine doped tin oxide coating on the undercoating layer of the present invention. The undercoating layer (composition and thickness) was the same for each sample.

(Example 4)
A piece of transparent glass (12 inches × 24 inches; 30 cm × 61 cm) was coated with the precursor using a CVD method. Half of the glass was coated directly on the glass with a fluorine-doped tin oxide coating, and the other half of the glass was coated with a silica, titania, phosphorous undercoating layer and a fluorine-doped tin oxide topcoat. Samples were cut from each part of the glass sheet and analyzed as described below.

(1) X-ray fluorescence (XRF) data The XRF data in Table 6 show similar amounts of [Sn] for both coatings (slightly larger for FTO / UL coating stacks).

(2) Haze and transmittance The samples were also tested for haze and transmittance. The results are shown in Table 7. The transmittance spectrum is shown in FIG. Compared to the fluorine-doped tin oxide (FTO) coating directly on the glass, the haze was greater and the transmittance was also greater with the fluorine-doped tin oxide (FTO) / undercoating layer (UL) coating stack. Thus, the undercoating layer of the present invention also provides a method for increasing the haze and transmittance of a coated article. This can be useful in the field of solar cells, where increasing haze increases the absorption process of electromagnetic energy, which in turn leads to an increased opportunity for electromagnetic energy to be absorbed.

(3) Surface resistance Table 8 shows data of surface resistance. The FTO / UL coating had a surface resistance of 1.5 ohm / sq lower than that of the FTO coating on glass.

(4) Coating thickness The thickness of the FTO coating, as determined by the etching method, was slightly greater for the FTO on glass (356 nm) versus the FTO on the UL (FTO top coating 334 nm).

(5) Porousness of coating The coating was observed using a scanning electron microscope (SEM). A large number of small holes were found in the FTO coating directly on the glass. In the FTO / UL coating stack, no holes were observed.

(6) Surface roughness The surface roughness was analyzed using an atomic force microscope (AFM) for regions of 10 micrometers (μm) × 10 μm; 5 μm × 5 μm; and 1 μm × 1 μm. The results are shown in Table 9. The surface roughness was greater for the FTO / UL coating stack than for FTO directly on glass. The increase in surface roughness increases the haze of the coating and, as a result, the absorption process of any electromagnetic energy that impinges.

(Example 5)
This example illustrates the effect of the undercoating layer of the present invention on the reflectance of the coated article.

FIG. 4 shows the change in reflectivity for a 10 nm to 120 nm TiO ₂ coating on glass (white rhombus, dashed line) and the same TiO ₂ layer on the undercoating layer of the present invention on glass. Undercoating layer is _{75% 13nm SiO 2 -20% TiO 2 -5} % P 2 O 5/49% SiO 2 -49% of _{23nm TiO 2 -2% P 2 O} 5 / 21nm of 75% SiO ₂ - It was 20% TiO ₂ -5% P ₂ O ₅ (black circle, solid line). The thickness change of TiO ₂ is from 10 nm to 120 nm with an interval of 5 nm.

FIG. 4 shows that the reflectivity fluctuates as the thickness of the TiO ₂ functional coating on the glass increases (ie, somewhere 11.7% <R <38.8%). However, when a TiO ₂ functional coating is deposited on the undercoating layer, the change in reflectivity is much smaller (ie, in the range of 17.2% to 27.4%). This indicates that the reflectivity of the entire coating stack with the underlying coating is not as sensitive to changes in the thickness of the top coating as it is without the underlying coating.

To a certain extent, reflectivity can be significantly reduced by the undercoating layer of the present invention. Table 10 shows the difference in reflectivity at 55 nm and 165 nm titania levels.

(Example 6)
This example illustrates the effect of the undercoating layer of the present invention on the color of the article (eg, a ^* and b ^* ).

5, TiO ₂ (open diamonds, dashed) of 120nm from 10nm on transparent glass, and a transparent glass on the under coating layer (13 nm of _{75% SiO 2 -20% TiO 2} -5% P 2 O 5 / 23nm for the _{49% SiO 2 -49% TiO 2} -2% P 2 O 5 / 21nm of _{75% SiO 2 -20% TiO 2} -5% P 2 O 5) the same coating on (closed circles, solid line), ^{a *} And b ^* change. The thickness change of TiO ₂ is 10 nm to 120 nm at 5 nm intervals.

FIG. 5 shows that when the thickness of the TiO ₂ functional coating increases, the color of the TiO ₂ coating without an underlayer (a ^* and b ^* ) swings greatly (−24 <a ^* <+ 37, and − 42 <b ^* <+ 34 somewhere). However, when the TiO ₂ functional coating is deposited on the undercoating layer as described above, a ^* and b ^* change only slightly (−8 <a ^* <+ 12 and −10 <b ^*). <+7). This means that the color of the entire coating stack with the underlying coating layer of the present invention is not as sensitive to changes in the thickness of the top coating as it is without the underlying coating.

(Example 7)
This example illustrates the effect of a gradient undercoat layer of silica and titania on the photocatalytic activity of a titania topcoat (120 nm thickness).

Table 11 shows the composition of the two gradient undercoating layers.

Table 12 shows the effect of the two undercoating layers of Table 11 on the photocatalytic activity of a 120 nm thick titania topcoat compared to the activity of titania without the undercoating layer. The unit of [Ti] is macrogram / cm ² .

  Those skilled in the art will readily appreciate that modifications can be made to the present invention without departing from the basic concept disclosed in the foregoing description. Accordingly, the specific embodiments described in detail herein are merely exemplary and are not a limitation on the scope of the invention, which is encompassed by the full scope of the appended claims and the scope thereof. Shown in all equivalents.

Claims (11)

substrate;
A first coating formed on at least a portion of the substrate, the first coating comprising at least two oxides selected from the group consisting of oxides of P, Si, Ti, Al, and Zr; And a functional coating formed on at least a portion of the first coating,
The first coating is
A first portion comprising phosphorous oxide, silica, and titania, wherein the titania is present at 10-25% by volume;
A second portion comprising phosphorus oxide, silica, and titania, wherein the titania is present in 36-50% by volume; and
A coated article comprising phosphorous oxide, silica, and titania, wherein the titania comprises a third portion present at 9-25% by volume . The article of claim 1, wherein the first coating further comprises an oxide of Al. substrate;
  A first coating formed on at least a portion of the substrate, the first coating comprising at least two oxides selected from P, Si, Ti, Al and Zr; and
  A functional coating formed on at least a portion of the first coating
Including
  The first coating is
  A first part comprising 5-10% by volume phosphorous oxide, 70-80% by volume silica and 10-25% by volume titania, the first part having a thickness of 11 nm to 29 nm;
  A second part comprising 2% by volume phosphorous oxide, 48-62% by volume silica and 36-50% by volume titania, the second part having a thickness of 21 nm to 33 nm; and
  A third part comprising 5-11% by volume phosphorous oxide, 70-80% by volume silica and 9-25% by volume titania, the third part having a thickness of 15 nm to 23 nm
A coated article comprising: The functional coating is Ti, Zn, Fe, Mn, Al, Ce, Sn, Sb, Hf, Zr, Ni, Zn, Bi, Ti, Co, Cr, Si, In, and two or more of these materials The article of claim 1 comprising at least one oxide selected from the group consisting of alloys. The article of claim 4, wherein the functional coating comprises at least one dopant selected from F, In, Al, and Sb. The article of claim 5, wherein the functional coating comprises tin oxide doped with fluorine. The article of claim 5, wherein the functional coating comprises titania.   −10 ≦ a ^* ≦ 2, and −15 ≦ b ^* The article of claim 1, having a color in the range of ≦ 0. A in the range of -8 to -4.4 ^* , B in the range of -12.6 to -5.2 ^* , And L in the range of 50.5 to 52.3 ^* The article of claim 8 having The article of claim 7, wherein the titania has a thickness in the range of 113 nm to 121 nm. Glass substrate;
  A first coating formed on at least a portion of the substrate, the first coating comprising at least two oxides selected from the group consisting of oxides of P, Si, Ti, Al, and Zr;
  A functional coating formed on at least a portion of the first coating, comprising an oxide selected from the group consisting of titania and fluorine doped tin oxide;
Including
  The first coating is
  A first portion comprising phosphorous oxide, silica, and titania, wherein the silica is present at 70-80% by volume;
  A second portion comprising phosphorus oxide, silica, and titania, wherein the silica is present at 48-62% by volume; and
  A coated article comprising phosphorous oxide, silica, and titania, wherein the silica comprises a third portion present at 70-80% by volume.

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