Technical Field

The present disclosure relates, in general to a solar control coated article comprising a transparent substrate, on the surface of which a stack of thin layers is deposited which comprises a functional layer based on NiCr or NiCrN. More specifically the invention relates to a solar control coated article having an improved resistance to corrosion while retaining an internal reflection of less than 10% for varying values of light transmission (TL) in the visible spectrum.

Background

The popularity of coated glass article in architecture and automotive design is well known. As reported prolifically in patent and other literature, such glass articles usually achieve, through the manipulation of the coating's layering system, quite acceptable degrees of reflectance, transmittance, emissivity, color matchability, and durability, as well as the color desired. It has also been well reported that while several reasonably acceptable techniques exist for applying such coatings, one of the most efficacious, and thus preferred, is the well-known technique referred to as "magnetically enhanced sputter coating".

Solar control glass has a large part to play in the future of construction, as external temperatures will continue to rise and so will the expectations of comfort. Legal agreements and devices aimed at reducing the environmental impacts of human activities are increasing on regional, national and international scales. These agreements and arrangements aim in particular to reduce the energy consumption of infrastructure. They recommend or oblige in particular the equipment of buildings and transport vehicles so as to reduce the energy consumption of their air conditioning and heating means.

With glazed surfaces often constituting the majority of the external surfaces of buildings and transport vehicles, there is a constantly growing need to meet the users demand in terms durability, particularly resistance of the glazing to corrosion in addition to acceptable degrees of reflectance, transmittance, emissivity, color matchability and color.

The absence of any substantial adverse effect upon heating the coating or its substrate, defines what is meant herein by the term "heat treatable". While in certain situations some characteristics may change somewhat during heat treatment, to be "heat treatable" as used herein means that the desired properties such as emissivity, sheet resistance, durability and corrosion resistance of the ultimate layer system and overall product must be achieved despite the fact that the coated glass has been subjected to one or more of the heat treatments (i.e. bending, tempering and/or heat strengthening). For most architectural purposes contemplated by this invention optimized heat treatability means that the glass and its layered coating remains substantially unchanged in at least its emissivity, sheet resistance, durability and corrosion resistance properties as between the pre-heat treated product and the final product after heat treatment.

In general, it has been found that resistance to corrosion of “heat treatable” solar control glasses in most cases diminish to unacceptably low levels post their heat treatment. This has been found to be particularly true for layer stack comprising: gl as s/di electric layer/metal alloy functional 1 ay er/di electric layer, the metal alloy functional layer being NiCr or NiCrN. In addition to the rather lower limit on heat treatment temperatures and times, these layer stack are rather soft and exhibit such unacceptably low chemical resistance characteristics that they can realistically be used only on the inner surfaces of laminated glass windshields. Color matchability attainable (before heat treatment vs. after heat treatment) is also not very advantageous.

It is also a common knowledge that such layer stacks comprising functional layers based on NiCr or NiCrN are susceptible to chloride attacks even in their annealed form, while their tempered counterparts suffer more severe susceptibility. This further leads to loss of solar control properties of the layer stack along with the loss in aesthetic characteristics. For example, in this respect, U.S. Pat. No. 5,688,585; 6,926,967; 1,055,034; European Pat. No. 747329 just to name a few are herein incorporated as references. In most of the prior art, the resistance to corrosion of the layer stack is determined by boiling a 2" *5" sample of a coated glass substrate in about 500 cc of 5% HC1 for one hour (i.e. at about 220° F.). The sample is deemed to pass this test (and thus the layer system is "chemically resistant" or is deemed to have "chemical durability") if the sample's layer system shows no pinholes greater than about 0.003" (76.2 p) in diameter after this one-hour boil. However, none of these prior art references suggest the layer stack to be durable or resistant to chemical corrosion for longer exposure. Although deemed to be a rigorous testing for establishing chemical resistivity of coated glass articles, this testing is far from the real time exposure conditions of the coated glass articles.

In real time installation conditions, the solar control coated articles can be subjected to harsh environmental conditions such as that in coastal regions where the presence of chloride ions is very high. In such cases the performance of these coated articles are severely impacted by their limited resistance to corrosion.

Secondly, the light transmission and the solar factor of the coated glass article depend in particular on the thickness of the functional layer that comprise the layer stack deposited on the surface of the transparent substrate which forms the glass surface. The light transmission and the solar factor vary contradictorily with the thicknesses of the functional layers. The thicker the functional layers, the lower is the light transmission and solar factor.

Thirdly, the coated glass article surfaces can also have an aesthetic function for buildings and transport vehicles in which they are likely to be incorporated. In certain applications, they must present, in external reflection, an appearance of neutral color, that is to say preferably close to the gray color. Such a surface appearance is generally desired for pleasant aesthetic appearance and is the result of the values of the two parameters a * and b * in the L * a * b * system being close to zero, ideally between -5 and 0. The external reflection depends partly on the thickness of the functional layers. The thicker the metallic functional layers, the higher the external reflection, and vice versa.

However, it has been found that any increase in the thickness of the functional metal causes a decrease in light transmission and solar factor. Therefore, although the external reflection increases as the thickness of the metallic functional layer increases, the selectivity (ratio of the light transmission to the solar factor, TL/g) decreases detrimentally for thermal performance (may not be entirety true for layer stack having multiple functional layers). It should further be noted that higher the reflection (be it internal and / or external) lower will be the visual comfort of building occupants and bystanders, respectively. Therefore, it is desirable and beneficial to keep the internal reflection low.

In brief, a thin functional layer is preferred for higher light transmission TL. On the other hand, if we increase the thickness of functional layer, solar factor comes down but both external and internal reflection increase. However, the materials currently in the market do not make it possible to combine a low solar factor and low internal reflection for a range of light transmission starting from a lower value of 7% up to a higher value of 65%, while achieving desired neutral external reflection.

As can be seen from the above, heretofore if the skilled artisan wished to achieve improved resistance to corrosion (i.e. chemical) resistance, but also wished to avoid costly downtime or the need to create a different layer system for matchability, while at the same time achieving heat treatability and yet have flexibility to vary the solar management properties over a reasonably wide range to avoid further production shutdowns (to meet the needs of different customers), that artisan was faced with an unsolvable problem.

It is apparent from the above that there exists a need in the art for a sputter-coated layer system which achieves the benefits of sputter-coating while overcoming the above-described problems and drawbacks in the art. It is a purpose of this invention to fulfill this need in the art as well as other needs which will become apparent to the skilled artisan once given the following disclosure.

The objective of the invention is therefore to develop a heat treatable material having:

Improved resistivity to corrosion;

- vary the solar management properties over a reasonably wide range of light transmission while maintaining lowest possible internal reflection; and exceptional aesthetic characteristics, in particular a neutral external color.

According to the invention, it is therefore sought to maximize corrosion resistance; flexible solar control properties; enhance aesthetics while keeping a light transmission suitable for allowing good insulation and good vision.

Unfortunately, none of the referenced prior art achieve all the optical, performance and aesthetic characteristics desired according to the present disclosure. It is thus a purpose of this disclosure to help achieve all the said characteristics, detail of which will become apparent to the skilled artisan once given the following disclosure.

Certain example embodiments of this disclosure relate to glazing that is durable having an increased thermal and chemical stability while retaining desired optical characteristics of the article. Certain example embodiments of this invention also relate to a process of making the same.

Summary of the Disclosure

In one aspect of the present disclosure, a solar control coated article comprising a transparent substrate coated with a stack of thin layers on at least one of its surface is disclosed. The stack of thin layers successively comprising, starting from the substrate: a first dielectric coating; a functional layer based on NiCr or NiCrN placed above the first dielectric coating; a metallic layer placed over and in direct contact with the functional layer; and a second dielectric coating placed above the metallic layer, wherein: the metallic layer is based on Ti or Nb and has a thickness not greater than 4 nm; and wherein the solar control article has a neutral external appearance in both reflection and transmission.

The present disclosure also relates to: a glazing comprising at least one solar control coated article according to the invention, the use of a glazing according to the invention for buildings or vehicles, a building or vehicle comprising a glazing according to the disclosure.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

Embodiments are illustrated by way of example and are not limited to those shown in the accompanying figures.

FIG. 1 illustrates a stack of thin layers deposited on a transparent glass substrate, according to one embodiment of the present disclosure; and

FIG. 2 illustrates a stack of thin layers deposited on a transparent glass substrate, according to an optional embodiment of the present disclosure.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

Detailed Description

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. Embodiments disclosed herein are related to solar control coated article having an improved resistance to corrosion while retaining an internal reflection of less than 10% for varying values of light transmission (TL) in the visible spectrum.

FIG. 1 illustrates a solar control glass article 500 comprising a stack of thin layers 200 having one function layer 50 based on NiCr or NiCrN sandwiched between a first dielectric coating 20 deposited below and a second dielectric coating 120 deposited above, all arranged on a transparent substrate 10. Deposited above and in direct contact with the functional layer 50 is a metallic layer 100 based on Ti or Nb. Although the basic stack configuration of glass: dielectric/ NiCr or NiCrN/ dielectric was largely known in the art, they were found and reported to be highly susceptible to chloride attack particularly after exposure to glass heat treatment temperatures. This resulted in reduced durability and product life.

In order to improve the resistivity of the basic stack configuration glass: dielectric/ NiCr or NiCrN/ dielectric to corrosion and to design a product with other desirable solar management and aesthetic properties the metallic layer 100 based on Ti or Nb was introduced to the stack of thin layers 200. Adding a metallic layer 100 based on Ti or Nb, metals that are highly chemically resistant significantly improves the durability of the underlying NiCr or NiCrN based functional layer 50. Further the metallic layer 100 is advantageously positioned directly above and in contact with the functional layer 50.

The present invention in general relates to performance of single glazed unit (SGU) with low internal reflection. The low internal reflection is achieved for different transmission levels in visible spectrum and neutral external reflection color. Adding to the aesthetic properties, is the ability of the stack of thin layers to block solar radiation and thus provides solar control properties.

The stack of thin layers 200 may further comprise an additional optional metallic layer 100’ (not represented) placed directly under and in direct contact with the functional layer 50 and at least one protective layer 150 (not represented).

By adjusting the thicknesses of the dielectric coatings 20, 120 to maintain the ratio of their thicknesses (20/120) to be less than 1.2 and restricting the dielectric coating 120 to 0.255* optical thickness measured at 550 nm i.e., maintaining the physical thickness of the dielectric coating 120 to be less than 78 nm, the desired advantageous optical characteristics viz., neutral external color in reflection and in transmission were surprisingly obtained by the inventors of the present invention. The optimized color values were maintained at a*ext -6 to +3; and b*ext -5 to +3 both in transmission color and reflection color. Further the thickness of the functional layer 50 was varied to get a wide range of transmission value: lowest of 7% and a highest of 65%. Furthermore, the thickness of specifically the dielectric coating 120 was adjusted to maintain the internal reflection values below 10% for all said varying values of light transmission in the visible spectrum. Finally, the combination of thicknesses of the first and second dielectric coating 20, 120 were adjusted in such a way that neutral color is achieved in light transmission and external reflection i.e., to maintain color values at: a*ext = -5 to +3, b*ext = -5 to +3; and a*T = -6 to 2 and b*T = -7 to 3. Finally, for the glazing comprising the solar control coated article to have no significant change in transmission and reflection color values post heat treatment, the metallic layer 100 based on Ti or Nb was maintained at thickness levels not greater than 4 nm.

Within the meaning of the present invention, the label “first” and “second” for dielectric coatings are defined starting from the substrate bearing the stack and with reference to the layers or coatings having the same function. For example, the dielectric coating closest to the substrate is the first dielectric coating, the next one moving away from the substrate is the second dielectric coating. Thicknesses stated in the present document with no other specifications are physical, real or geometric thicknesses are expressed in nanometers (and not optical thicknesses).

According to one embodiment of the present invention, the functional layer 50 satisfy the condition: the thickness of the functional layer 50 does not exceed 30 nm, inclusive of said value. The thickness of the functional layer 50 is varied to achieve varying values of light transmission (TL) in the visible spectrum ranging between 7% and 65%. According to one embodiment, the thickness of the functional layer 50 being NiCr ranges between 0.1 nm and 25 nm. According to another embodiment, the thickness of the functional layer 50 being NiCrN ranges between 0.1 nm and 35 nm. According to yet another embodiment of the present invention, the functional layer 50 is partially or completely oxidized.

According to yet another embodiment of the present invention, the metallic layer 100 deposited as over layer in contact with the functional layer 50 acts as a barrier layer. The role of the barrier layer is conventionally to protect the functional layer from a possible degradation during the deposition of the second dielectric coating 120 and during high-temperature heat treatment of the bending and/or tempering type. The barrier layer is selected from metallic layers based on a metal selected from Ti or Nb. When the barrier layer is deposited in metallic form, the layer may undergo a partial or complete oxidation depending on their thickness and the nature of the layer that surround them, for example, at the time of the deposition of the next layer or by oxidation in contact with the underlying layer. Nevertheless, the barrier layer deposited in metallic form does not oxidize the functional layer 50 underlying it during deposition and/ or further processing such as heat treatment which is advantageous for obtaining the many desired optical and performance characteristics of the solar control coated article 500 of the present invention.

According to one embodiment of the present invention, the metallic layer 100 satisfy the condition: the functional layer 50 is in contact with at least one metallic layer 100 selected from a barrier over layer (as illustrated in FIG. 1); and/or the functional layer 50 is in contact with a barrier under layer and a barrier over layer (as illustrated in FIG. 2); and/or the thickness of each barrier layer does not exceed 4 nm and ranges preferably between 0.1 nm and 4 nm.

According to one other embodiment of the present invention, the metallic layer 100 is preferably based on Ti and is deposited as a continuous layer or a discontinuous layer. In a preferred embodiment the metallic layer 100 based on Ti is deposited as a discontinuous layer with a preferred thickness of less than 2 nm, in a particular exemplary embodiment.

According to another embodiment, the dielectric coatings 20, 120 satisfy the condition: the thickness of the second dielectric coatings 120 is greater than or equal to the thickness of the first dielectric coating 20; and/or thickness of first dielectric coating 20 does not exceed 65 nm; and/or thickness of second dielectric coating 120 is greater than 45 nm and less than 78 nm; the two dielectric coatings 20, 120 comprise at least one dielectric layer based on a material selected from silicon nitride, titanium nitride, aluminum nitride or oxynitrides of silicon and aluminum, zinc oxide, tin and zinc oxide, tin oxide, titanium oxide, silicon oxide, titanium and tin oxide, alone or in combination; the two dielectric coatings 20, 120 each comprise one or combination of other dielectric layer. According to another embodiment of the present invention, the first dielectric coating 20 comprises at least one dielectric layer positioned below the functional layer 50; this dielectric layer has a barrier function and is based on oxides such as SiO2 and A12O3, silicon nitrides Si3N4 and AIN and oxynitrides SiOxNy and AlOxNy, most preferably silicon nitride optionally doped with aluminum, having a thickness not exceeding 65 nm. According to another aspect of this embodiment, the dielectric coating 20 may comprise two dielectric layers whose combined thickness does not exceed 65 nm. According to yet another aspect of this embodiment, the dielectric layer is placed directly below and in contact with the functional layer 50 if the additional metallic layer based on Ti or Nb is absent. According to yet another aspect of this embodiment, the dielectric layer is placed directly below but not in contact with the functional layer 50 if the additional metallic layer based on Ti or Nb is present.

According to another embodiment of the present invention, the second dielectric coating 120 comprises at least one dielectric layer positioned above the first functional layer 50; this dielectric layer also has a barrier function and is based on oxides such as SiO2 and A12O3, silicon nitrides Si3N4 and AIN and oxynitrides SiOxNy and AlOxNy, most preferably silicon nitride optionally doped with aluminum, having a thickness ranging between 45 nm and 78 nm. According to another aspect of this embodiment, the dielectric coating 120 may comprise two dielectric layers whose combined thickness ranging between 45 nm and 78 nm. In all embodiments of the present invention, the dielectric coating 120 is placed above the functional layer 50 but not on direct contact with the functional layer 50 unlike the dielectric coating 20.

Dielectric layer having a barrier function according to the present invention should be understood as a layer made of a material capable of forming a barrier to the diffusion of sodium, oxygen and/or water at high temperature, originating from the ambient atmosphere or from the transparent substrate, toward the functional layer. The constituent materials of the dielectric layer having a barrier function thus must not undergo chemical or structural modification at high temperature which would result in a modification to their optical properties. The layer or layers having a barrier function are preferably also selected from a material capable of forming a barrier to the constituent material of the functional layer. The dielectric layers having a barrier function thus allow the stack to be subjected, without excessively significant optical change, to heat treatment, tempering or bending.

According to an optional embodiment of the present invention, the stack of thin layers 200 comprises at least one protective layer 150 (as illustrated in FIG. 2) deposited farthest from the surface capable of being in contact with the atmosphere based on titanium zirconium nitride or oxynitirde, titanium zirconium oxide or titanium oxide, alone or in combination. The protective layer generally has a thickness of less than 10 nm, more preferably less than 5 nm. Further the stack of thin layer 200 comprises an optional additional metallic layer 100’ based on Ti or Nb placed directly under and in contact with the functional layer 50.

According to a particular exemplary embodiment of the present invention, the stack of thin layers 200 comprises starting from the glass substrate 10: a first dielectric coating comprising one dielectric layer having a barrier function based on Si3N4; optionally a metallic layer based on Ti; a functional layer based on NiCr or NiCrN; a metallic layer based on Ti; a second dielectric coating comprising one dielectric layer having a barrier based on Si3N4; and optionally one protective layer based on TiZrO _x .

The transparent substrates according to the present invention are preferably made of an inorganic rigid material, such as glass, or an organic material based on polymers (or made of polymer). The substrate is preferably a sheet of glass or of glass-ceramic. The substrate is preferably transparent, colorless (it is then a clear or extra-clear glass) or colored, for example colored blue, green, grey or bronze. The glass is preferably of soda-lime-silica type, but it may also be made of glass of borosilicate or alumino-borosilicate type. The substrate advantageously has at least one dimension greater than or equal to 1 m, or even 2 m and even 3 m. The thickness of the substrate generally varies between 0.5 mm and 19 mm, preferably between 0.7 and 9 mm, in particular between 2 and 12 mm, or even between 4 and 6 mm. The substrate may be flat or curved, or even flexible.

The material, that is to say the substrate coated with the stack, may undergo a high-temperature heat treatment such as an annealing, for example a flash annealing such as a laser or flame annealing, a tempering and/or a bending. The temperature of the heat treatment is greater than 600°C, preferably greater than 650°C., and better still greater than 700°C. The substrate coated with the stack may therefore be curved and/or tempered.

The invention also relates to a glazing comprising a solar control coated article 500 according to the invention. Conventionally, the faces of a glazing are denoted starting from the outside of the building and by numbering the faces of the substrates from the outside towards the inside of the passenger compartment or room that it equips. This means that the incident solar light passes through the faces in the increasing order of their number.

The stack 200 is preferably positioned in the glazing so that the incident light coming from outside passes through the first dielectric coating 20 before passing through the functional layer 50. The stack is not deposited on the face of the substrate that defines the external wall of the glazing but on the inner face of this substrate. The stack is therefore advantageously positioned on face 2, face 1 of the glazing being the outermost face of the glazing, as is customary.

The material may be intended for applications that require the substrate coated with the stack to have undergone a heat treatment at a high temperature such as a tempering, an annealing or a bending. The glazing of the invention may be in the form of monolithic, laminated or multiple glazing, in particular double glazing or triple glazing.

In the case of a monolithic or multiple glazing, the stack is preferably deposited on face 2, that is to say that it is not on the substrate that defines the external wall of the glazing and more specifically on the inner face of this substrate. A monolithic glazing comprises 2 faces; face 1 is on the outside of the building and therefore constitutes the external wall of the glazing, face 2 is on the inside of the building and therefore constitutes the internal wall of the glazing.

A multiple glazing comprises at least two substrates kept at a distance so as to delimit a cavity filled by an insulating gas. The materials according to the invention are very particularly suitable when they are used in double glazings with enhanced thermal insulation (ETI). A double glazing comprises 4 faces; face 1 is outside of the building and therefore constitutes the external wall of the glazing, face 4 is inside the building and therefore constitutes the internal wall of the glazing, faces 2 and 3 being on the inside of the double glazing.

In the same way, a triple glazing comprises 6 faces; face 1 is outside of the building (external wall of the glazing), face 6 is inside the building (internal wall of the glazing) and faces 2 to 5 are on the inside of the triple glazing. A laminated glazing comprises at least one structure of first substrate/sheet(s)/second substrate type. The stack of thin layers is positioned on at least one of the faces of one of the substrates. The stack may be on the face of the second substrate not in contact with the, preferably polymer, sheet. This embodiment is advantageous when the laminated glazing is assembled as double glazing with a third substrate.

The glazing according to the invention, used as monolithic glazing or in a multiple glazing of double glazing type, has neutral and pleasant appearance in external reflection and transmission. The internal reflection is kept lesser than 10%. These two features aid in visual comfort for people facing the interior and exterior of the glazing.

The glazing of the invention has colors in transmission in the L*a*b* color measurement system: a*T between -6 and 2, preferably between -4.0 and 1.0**; in a particular exemplary embodiment a*T is -2.9; b*T between -7.0 and 3, preferably between -6.0 and2.0; in a particular exemplary embodiment b*T is -5.8. The glazing of the invention has colors in reflection on the external side in the L*a*b* color measurement system: a*ext between -5 and 3, preferably between -4.0 and 1.0; in a particular exemplary embodiment a* ext is -3.6; b* ext between -5 and 3, preferably between -4 and 2.0; in a particular exemplary embodiment b* ext is 1.8.

According to advantageous embodiments, the glazing of the invention in the form of a glazing comprising the stack positioned on face 2 makes it possible to achieve, in particular, the following performances: a solar factor less than or equal to 70%, preferably less than or equal to 65%, and/or a light reflection on the internal side of less than or equal to 10%, preferably less than or equal to 8%, and/or neutral color in external reflection and transmission.

Preferably, the stack is deposited by magnetron sputtering. According to this advantageous embodiment, all the layers of the stack 200 are deposited by magnetron sputtering.

Examples

Example 1

Preparation of the Substrates: Stack of thin layers

Stack of thin layers, defined below, are deposited on substrates made of clear soda-lime glass with a thickness of 6 mm.

In the example of the invention: the functional layers are layers of NiCr, the metallic layers made of titanium (Ti), the dielectric layers are based on silicon nitride (SisN^, the protective layer is made of titanium zirconium oxide (TiZrOx).

Table 1 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to the substrate bearing the stack (final line at the bottom of the table). The “Ref.” numbers correspond to the references from FIG. 1.

Table 1 : Stack of thin layers

Solar Control and Optical Properties

Table 2 lists the main optical characteristics measured when the glazings are part of monolithic structure, the stack being positioned on face 2 (face 1 of the monolithic glazing being the outermost face of the glazing, as is customary). For these monolithic glazings:

TL indicates: the light transmission in the visible region in %, measured according to the illuminant D65 Obs 2; a*T and b*T indicate the a* and b* colors in transmission in the L*a*b* system measured according to the illuminant D65 Obs 2 and measured perpendicularly to the glazing;

Rext indicates: the light reflection in the visible region in %, measured according to the illuminant D65 Obs 2 on the side of the outermost face, face 1; a*Rext and b*R _ex t indicate the a* and b* colors in reflection in the L*a*b* system measured according to the illuminant D65 Obs 2 on the side of the outermost face and thus measured perpendicularly to the glazing;

Rint indicates: the light reflection in the visible region in %, measured according to the illuminant D65 Obs 2 on the side of the internal face, face 4; a*Rint and b*Rint indicate the a* and b* colors in reflection in the L*a*b* system measured according to the illuminant D65 Obs 2 on the side of the internal face and thus measured perpendicularly to the glazing.

Table 2: Optical & Solar Control Properties

While the TL values and color in transmission and reflection are similar for sample 1 prepared according to the teaching of the present invention and comparative sample 1, a thickness reduction of about 10 nm in the second dielectric layer of the comparative sample 1 almost doubles the internal reflection of the sample. This is because the condition for the dielectric layers: ratio of thickness of the first dielectric coating to the thickness of the second dielectric coating should be less than 1.2 is not maintained in the comparative sample 1. Example 2 Heat Treatment of Solar Control Coated Article

Table 3 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to the substrate bearing the stack (final line at the bottom of the table). The “Ref.” numbers correspond to the references from FIG. 1. Table 3 : Stack of thin layers

Solar Control and Optical Properties Table 4 lists the main optical characteristics measured when the glazings are part of monolithic structure, the stack being positioned on face 2 (face 1 of the monolithic glazing being the outermost face of the glazing, as is customary).

Table 4: Optical & Solar Control Properties

Sample 2 including a metallic layer of Ti according to the teachings of the present invention and comparative sample 2 without any metallic Ti layer were heat treated (tempered) at 630°C for about 6 minutes and the color

5 matchability post tempering was assessed. The results tabulated in table 5 demonstrates that the presence of Ti layer in sample 2 does not influence the tempering shift in the sample and the results are similar.

Table 5: Calorimetric Values

10 Example s

Retaining Low Internal Reflection Values for similar Light Transmission & Neutral Aesthetics

Table 6 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to 15 the substrate bearing the stack (final line at the bottom of the table). The “Ref.” numbers correspond to the references from FIG. 1.

Table 6: Stack of thin layers Solar Control and Optical Properties

Table 7 lists the main optical characteristics measured when the glazings are part of monolithic structure, the stack being positioned on face 2 (face 1 of the monolithic glazing being the outermost face of the glazing, as is 5 customary).

Table 7: Optical & Solar Control Properties

From the optical characteristics of sample 3 and comparative sample 3, it can be understood that for similar visible transmission values, the 10 external reflection of these samples can be controlled by varying the thicknesses of 20, 120 & 50 while still retaining the neutral external aesthetic and low internal reflection values. Comparative sample 3 is to demonstrate how the introduction of the metallic Ti layer does not significantly impact the optical properties but only contributes to the improvement of chemical resistivity of the sample.

15 Example 4

Continuous Vs Discontinuous Metallic Ti Layer

Table 8 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to the substrate bearing the stack (final line at the bottom of the table). The “Ref.” 20 numbers correspond to the references from FIG. 1.

Table 8: Stack of thin layers

Solar Control and Optical Properties

Table 9 lists the main optical characteristics measured when the glazings are part of monolithic structure, the stack being positioned on face 2

5 (face 1 of the monolithic glazing being the outermost face of the glazing, as is customary).

Table 9: Optical & Solar Control Properties

The inventors of the present invention have accidentally found that

10 the metallic Ti layer used in the stack of thin layers 200 of the present invention can be deposited as a discontinuous layer at thickness ranges below 4 nm and this discontinuous islands of metallic Ti becomes a continuous layer when the layer thickness exceeds 4 nm. Thus the comparative sample 4 of this example has a continuous metallic Ti layer with thickness of 7 nm and the sample 4 prepared

15 according to the teaching of the present invention has a thickness of only 1.5 nm.

The inventors have further found by trial and error method that when this metallic Ti layer is deposited as a continuous layer having thickness above 4 nm, the visible light transmission of the coated article decreases and the external reflection of the coated article increases. Further the external reflection

20 color turns more yellowish when compared to a coated article having a discontinuous metallic Ti layer (sample 4).

Example 5

NiCrN as the functional layer 50:

Stack of thin layers, defined below, are deposited on substrates

25 made of clear soda-lime glass with a thickness of 6 mm. In the example of the invention: the functional layers are layers of NiCrN, the metallic layers made of titanium (Ti), the dielectric layers are based on silica nitride (Si3N4),

5 the protective layer is made of titanium zirconium oxide (TiZrOx).

Table 9 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to the substrate bearing the stack (final line at the bottom of the table). The “Ref.” numbers correspond to the references from FIG. 1.

10 Table 9: Stack of thin layers

Solar Control and Optical Properties

Table 10 lists the main optical characteristics measured when the glazings are part of monolithic structure, the stack being positioned on face 2 15 (face 1 of the monolithic glazing being the outermost face of the glazing, as is customary).

Table 10: Optical & Solar Control Properties

Sample 5 and 6 are added to demonstrate that the functional layer

20 50 be it NiCr ot NiCrN retains the same optical characteristics for the desired external reflection and transmission. Further samples 1, 2 & 3 prepared according to the teachings of the present invention demonstrate that varied visible transmission values are achievable while retaining a neutral external reflection color and transmission color and low internal reflection value of less than 10%.

Example 6

CASS Test (Resistivity to Corrosion - Testing)

CASS test was performed as per ISO 9227:2012. CASS solution was prepared by adding 5% NaCl salt in DI water following which 0.26 g/liter of dehydrated CuCh was added. Acetic acid was added to adjust the pH in the range of 3-3.1. During the test, the temperature of the testing chamber was maintained at 50°C. The microscopic images of the solar control coated article prepared according to the teachings of the present invention were observed initially (before testing) and after exposure to CASS solution for a period of 28 days (accelerated testing period) were compared to identify any visible defects or scratches. Samples were deemed to fail the test if the defect area was greater than 300 pm ² and the number of defects were greater than 100 or the equivalent area for the image taken at lOx magnification in optical microscope. Tempered comparative sample 2 was also exposed to CASS test. Microscopic images of the tempered comparative sample 2 revealed a lot of defects suggesting the degradation of the stack of thin layers resulting in significant degradation of the coating’s performance.

Table 11 : Chemical durability

Whereas microscopic images of sample 2 (including a metallic Ti layer) showed no defects both for tempered as well as annealed samples. This demonstrates that the stack of thin layers is intact post the extended exposure and the performance of the coating is not impacted.

Example 7 Table 12 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to the substrate bearing the stack (final line at the bottom of the table). The “Ref.” numbers correspond to the references from FIG. 2. Sample 7 was constructed according to one embodiment of the present invention wherein the stack of layers comprise an additional metallic layer provided below the functional layer.

Table 12: Stack of thin layers

Solar Control and Optical Properties Table 13 lists the main optical characteristics measured when the glazings are part of monolithic structure, the stack being positioned on face 2 (face 1 of the monolithic glazing being the outermost face of the glazing, as is customary).

Table 13: Optical & Solar Control Properties

Table 13 illustrates that the introduction of an additional Ti layer below the functional layer also results in the desired properties of the solar control article according to the present invention and further the optical results of the heat treated solar control article and its counterpart are similar. Further it was also seen that the additional Ti layer does not influence the tempering shift in the sample and the results are similar.

Industrial Applicability

The glazing described in the present disclosure finds application as a glazed element in building. In this application case, the glazing may form a monolithic, a double or triple glazing with the coating side of the glass arranged facing the closed space inside the multiple glazing. The glazing may also form a laminated glazing whose stack of layers may be in contact with the thermoplastic adhesive material connecting the substrates, in general PVB. The glazing according to the invention is, however, particularly useful when the multilayer stack is facing the outer environment, whether it is an insulated glazing or laminated glazing, but also optionally a multiple glazing. The glazing may also be enameled. The glazing of the present disclosure can also be annealed, strengthened, toughened, tempered or curved and/or bent.

The tempered glazing can also be used in building wall cladding panel of curtain walling for interior applications. Further can also be used as a side window, rear window or sunroof for an automobile or other vehicle.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one 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).

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

List of Elements

TITLE: A SOLAR CONTROL COATED ARTICLE WITH IMPROVED

RESISTANCE TO CORROSION

10 Glass Substrate

20 First Dielectric Coating

50 Functional Layer

100, 100’ Metallic Layer

120 Second Dielectric Coating

150 Protective Layer