EP4149897A1

EP4149897A1 - Low-e material comprising a thick layer based on silicon oxide

Info

Publication number: EP4149897A1
Application number: EP21732439.1A
Authority: EP
Inventors: Yann COHIN; Maëlis BANCI; Corinne Victor
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2020-05-12
Filing date: 2021-05-07
Publication date: 2023-03-22
Also published as: FR3110160A1; MX2022014175A; CO2022016074A2; FR3110160B1; WO2021229165A1; BR112022021996A2; US20230212065A1

Abstract

The invention relates to material comprising a transparent substrate coated with a stack comprising at least one functional metal layer based on silver and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, in such a way that each functional metal layer is positioned between two dielectric coatings, characterized in that the stack comprises a layer based on silicon oxide having a thickness of greater than or equal to 12 nm located directly in contact with the substrate.

Description

Title of the invention: Low emissivity material comprising a thick layer based on silicon oxide

The invention relates to a material comprising a transparent substrate coated with a stack comprising a functional silver-based metal layer. The invention also relates to glazing comprising these materials as well as the use of such materials for manufacturing glazing.

Functional silver-based metallic layers (or silver layers) have advantageous electrical conduction and infrared (IR) radiation reflection properties, hence their use in so-called “solar control” glazing aimed at reducing the amount of incoming solar energy and / or in so-called “low-emissive” glazing aimed at reducing the amount of energy dissipated to the outside of a building, a vehicle or a device.

These silver layers are deposited between coatings based on dielectric materials generally comprising several dielectric layers (hereinafter "dielectric coatings") making it possible to adjust the optical properties of the stack. These dielectric layers also help protect the silver layer from chemical or mechanical attack.

The invention relates very particularly to a material used to manufacture a glazing used as a component of a heating or cooling device.

A heating device comprises an enclosure delimited by one or more walls and heating means so as to allow the enclosure to be heated to a high temperature. The heating devices can in particular be chosen from ovens, fireplaces, stoves, etc. According to the invention, the heating means are distinct from the stack of thin layers. Heated automotive glazing, the stack of which serves as a heating element that does not correspond to a heating device according to the invention.

A refrigerating device comprises an enclosure delimited by one or more walls and means making it possible to cool the enclosure to a temperature below the normal temperature (20 ° C). The refrigerating devices can in particular be chosen from:

- refrigerators for which the desired temperatures vary between 0 and 20 ° C (positive cold),

- freezers for which the desired temperatures are below 0 ° C (negative cold). The glazing used as constituent elements of a refrigerating device of the freezer type (negative cold) are generally monolithic glasses.

The glazing used as component parts of a refrigerator-type heating or cooling device (positive cold) are generally multiple glazing.

According to the invention, a multiple glazing comprises at least two substrates kept at a distance so as to delimit a space. The faces of the glazing are designated from the inside of the heater or cooler and by numbering the faces of the substrates from the inside (inner face) to the outside (outer face) of the heater or cooler.

In the case of multiple glazing for a heating device, the different substrates are generally arranged side by side in an open space.

In the case of multiple glazing for a refrigerator-type refrigerating device, the various substrates are generally interconnected so as to form an airtight cavity between two substrates.

These glazing help maintain a set temperature inside the device while keeping the exterior surface of the glazing normally cool to the touch for the protection and comfort of users.

The use of a substrate coated with a functional coating reflecting infrared (IR) radiation in glazing used as component parts of a heating or cooling device allows:

- reduce the amount of energy dissipated to the outside in the case of a heating device by reflecting the heat towards the enclosure,

- reduce the amount of energy entering the interior of the enclosure in the case of a refrigeration device by reflecting the heat to the outside.

The use of these coatings helps to reduce the consumption of the heating or cooling device and the heating or cooling of the glazing.

Coatings comprising functional silver-based metallic layers (or silver layers) are the most effective for reducing the emissivity of glazing while preserving optical and aesthetic qualities. These coatings provide better user protection, lower energy consumption and greater comfort of use.

However, the chemical, thermal and mechanical resistance of the coatings comprising these functional silver-based metallic layers is often insufficient. This low resistance results in use under normal conditions, and a fortiori in more extreme conditions, by the short-term appearance defects such as corrosion spots, scratches, or even total or partial tearing of the stack.

This phenomenon is accentuated when these glazings are used in heating devices, especially when they are subjected to long and repeated heat treatment cycles at high temperatures in a humid environment.

This phenomenon is also accentuated when these glazings are used in refrigeration devices, especially when they are constantly subjected to a humid environment.

These extreme conditions further accelerate the degradation of silver layers, particularly by dewetting or corrosion of the silver. Any defects or scratches, whether due to corrosion or mechanical stress, are liable to alter not only the energy and optical performance but also the aesthetics of the coated substrate.

The applicant has developed a functional coating which is particularly suitable for these applications. This coating comprises a single functional silver-based layer protected by an undercoat and a blocking overlay. The dielectric coatings surrounding the functional layer essentially consist of oxide-based layers.

This coating is particularly suitable for refrigeration and heating device applications because it has both:

- high chemical durability with in particular resistance greater than 56 days in the High Humidity test), and

- low emissivity (around 3%).

The excellent chemical durability may be due to the nature of its dielectrics which are primarily oxides.

However, in order to be used in heating or cooling devices, the materials must undergo a high temperature heat treatment such as quenching. However, the functional coating developed by the applicant remains sensitive to overheating, both during its quenching and during its potential use in a heating device. This sensitivity to heat treatment could be due to the nature of its dielectrics, which are composed exclusively of oxides.

The silver-based functional layer is unstable and dewets during heat treatment at elevated temperature. This dewetting is characterized by the appearance of holes in the silver layer. These holes are called dendritic because of their shape often branched. These holes in the silver layer have two very damaging consequences for the product.

The product becomes blurry (after quenching, since the edge of the holes in the silver layer diffuses the light). Visually, this blur corresponds to the appearance of a more or less milky veil. This blur can be inhomogeneous because it can reveal defects on the surface of the glass (traces of drying, marks of suction cups handling the glass, etc.).

The product's emissivity, its key performance, is severely degraded by these holes. Indeed, we can show that in each hole, it is no longer the emissivity of the silver layer (3%, for example) that is to be taken into account, but that of the glass (close to 89%). Thus, if the holes represent only 1% of the area, the emissivity is already degraded by about 1.8 points, going from 3% to almost 5%.

There are a number of patent applications disclosing functional silver-based coatings comprising a thin low index layer which may be silicon oxide based in contact with the substrate. Among these applications, mention may be made of application EP1480920. The goal of these low index layers is to reduce haze following heat treatment of stacks including a silver-based functional layer. These layers would reduce the negative impact of aging of the glass substrate by "regenerating" the surface of a potentially degraded glass substrate, for example following long storage.

These applications or patents are not concerned with the problem of heating or cooling devices. The maximum thickness of these silicon oxide intermediate layers is 10 nm. Finally, these applications do not disclose stacks essentially consisting of an oxide layer exhibiting advantageous chemical durability.

The applicant has surprisingly discovered that this double optical / emissivity degradation can be largely eliminated while retaining the very good chemical durability of the product. In fact, certain technical solutions allow a strong improvement in the haze on quenching, without however maintaining the chemical durability necessary for the material, which is then largely weakened.

The solution of the invention consists in placing an intermediate layer based on silicon oxide with a thickness greater than 12 nm between the glass substrate and the first dielectric layer of the stack.

The solution of the invention has the significant advantage that it does not require any other modification of the stack already developed by the applicant. In fact, the use of this layer of optical index close to glass does not then require any modification of the stack already developed, because these layers are optically neutral. Light interference at the glass / Si02 interface is negligible.

The superior resistance to heating in the presence of such an interlayer is not only true when quenching, but also when used in a heater.

For example, the use of a 14 nm layer of silicon oxide in a functional coating has an 8 times greater resistance to heating at a temperature of 450 ° C than that of the same functional coating without a layer of silicon oxide. The term 8 times greater resistance is understood to mean that the material provided with a stack comprising a 14 nm layer of silicon oxide can be heated at the same temperature for a time 8 times longer than the same stack without an oxide layer. silicon, before exhibiting the same degree of degradation.

The applicant has discovered that there is a range of thicknesses for this silicon oxide layer to be observed so as to have an anti-blurring effect and very good chemical durability. The advantageous effects of the invention are not obtained for thicknesses less than 12 nm.

In particular, the Applicant has discovered that the use of a silicon oxide layer allows the degradation of the functional coating to be delayed. However, for this degradation delay to be sufficient not to cause degradation:

- during heat treatment at high temperature, i.e. at a temperature above 550 ° C for several minutes, or

- during long and repeated heating cycles (duration greater than 15 minutes) at a temperature between 100 ° and 250 ° C, a minimum thickness of silicon oxide is required, and in particular a thickness of at least 12 nm.

Indeed, thanks to the use of a silicon oxide layer of at least 12 nm, the time / temperature pair during heating becomes compatible with a transformation of the glass, such as toughening or bending, without blurring or degradation of emissivity. On the hardening and bending tools used, the glazing comprising a functional coating without a thick silicon oxide layer in contact with the substrate shows a haze at time and temperature parameters very close to those necessary to obtain flatness, fragmentation, and an acceptable form. Industrial tools used for bending and / or soaking substrates including coatings functionalities may also exhibit variability. A material must therefore be robust enough to accept these process variabilities. The materials of the invention have this additional strength. The observed degradation delay (several tens of seconds at 705 ° C) is sufficient to ensure that the materials will not be degraded, regardless of the variability of the quenching process.

The invention therefore relates to a material comprising a transparent substrate coated with a stack comprising at least one functional metallic layer based on silver and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is placed between two dielectric coatings, characterized in that the stack comprises a silicon oxide-based layer with a thickness greater than or equal to 12 nm located directly in contact with the substrate.

The invention also relates to:

- a glazing comprising a material according to the invention,

- a glazing comprising a material according to the invention mounted on a device, on a vehicle, in particular a motor vehicle or on a building, and

- the process for preparing a material or glazing according to the invention,

- the use of glazing according to the invention as solar control glazing and / or low emissivity for the building or vehicles,

- a building, a vehicle or a device comprising glazing according to the invention.

The invention also relates to a heating or cooling device comprising heating or cooling means and an enclosure delimited by one or more walls, at least one wall of which comprises at least one glazing comprising a material according to the invention.

The invention is particularly suitable as a freezer-type refrigerating device. In this case, the glazing can be made of the material (monolithic glazing) with preferably the stack located on the face of the substrate in contact with the enclosure.

The glazing of the invention is also suitable in all applications requiring the use of a stack comprising layers of silver for which the resistance to repeated heat treatments and to corrosion in a hot and cold humid environment are key parameters. . We can mention in particular:

- glazing for oven doors, pyrolytic or not,

- glazing for the fireplace insert door, - glazing for fire doors,

- glazing for heating elements such as radiators and towel dryers.

The invention also relates to the use of glazing as a constituent element of a cooling device, of a heating device or of a fire door, the glazing comprising a material according to the invention.

The glazing can be chosen from multiple glazing comprising at least two transparent substrates.

The glazing can also consist solely of the material according to the invention. In this case, it has only one substrate. It is then a simple glazing or monolithic glazing.

Throughout the description, the substrate according to the invention is considered to be laid horizontally. The stack of thin layers is deposited on top of the substrate. The meaning of the expressions “above” and “below” and “lower” and “upper” should be considered in relation to this orientation. In the absence of a specific stipulation, the expressions “above” and “below” do not necessarily mean that two layers and / or coatings are placed in contact with one another. When it is specified that a layer is deposited "in contact" with another layer or a coating, this means that there cannot be one (or more) layer (s) interposed between these. two coats (or coat and coating).

All the luminous characteristics described are obtained according to the principles and methods of European standard EN 410 relating to the determination of the luminous and solar characteristics of glazing used in glass for construction. The sunlight entering a building is considered to flow from the exterior to the interior.

The preferred characteristics which appear in the remainder of the description are applicable both to the material according to the invention and, where appropriate, to the glazing units, to the devices or to the process according to the invention.

The material, that is, the transparent substrate coated with the stack, is intended to undergo heat treatment at elevated temperature. Therefore, the stack and the substrate have preferably been subjected to heat treatment at an elevated temperature such as quenching, annealing or bending.

The stack is deposited by cathodic sputtering assisted by a magnetic field (magnetron process). According to this advantageous embodiment, all the layers of the stack are deposited by cathodic sputtering assisted by a magnetic field. The material and the glazing of the invention are transparent, that is to say not opaque. According to an advantageous embodiment, the material or the glazing according to the invention has a light transmission greater than 35%, greater than 40%, greater than 45% or greater than 50%.

Unless otherwise stated, the thicknesses mentioned in this document are physical thicknesses and the layers are thin layers. The term “thin layer” is understood to mean a layer having a thickness of between 0.1 nm and 100 micrometers.

The stack comprises a silicon oxide-based layer greater than 12 nm thick located directly in contact with the substrate.

The silicon oxide-based layer has a thickness:

- greater than or equal to 12 nm, greater than or equal to 13 nm or greater than or equal to 14 nm,

- less than or equal to 60 nm, less than or equal to 40 nm, less than or equal to 30 nm, less than or equal to 25 nm, less than or equal to 20 nm or less than or equal to 18 nm.

The silicon oxide-based layer can include other elements. These elements can be selected from aluminum, boron, titanium, and zirconium. Preferably, the elements are selected from aluminum, boron and titanium.

The silicon oxide-based layer may comprise at least 60%, at least 65%, at least 70% at least 75.0%, at least 80% or at least 90% by mass of silicon relative to the mass of all the elements constituting the silicon oxide-based layer other than oxygen.

Preferably, the silicon oxide-based layer comprises at most 35%, at most 30%, at most 20% or at most 10% by mass of elements other than silicon relative to the mass of all elements. constituting the layer based on silicon oxide other than oxygen.

The layer based on silicon oxide may comprise at least 2%, at least 5.0% or at least 8% by mass of aluminum relative to the mass of all the elements constituting the layer based on silicon oxide. silicon other than oxygen.

The amounts of oxygen and nitrogen in a layer are determined in atomic percentages relative to the total amounts of oxygen and nitrogen in the layer in question.

According to the invention, the layers based on silicon oxide essentially comprise oxygen and very little nitrogen. Silicon oxide-based layers include greater than 90%, greater than 95% or 100% atomic percent oxygen to oxygen and nitrogen in the silicon oxide based layer.

The silicon oxide-based layer can be obtained:

- by cathodic sputtering,

- from a metallic silicon target or a ceramic target based on silicon oxide.

The functional silver-based metal layer, before or after heat treatment, comprises at least 95.0%, preferably at least 96.5% and better still at least 98.0% by mass of silver relative to the mass of the functional layer.

Preferably, the functional silver-based metal layer before heat treatment comprises less than 5% or less than 1.0% by weight of metals other than silver based on the weight of the functional metal layer based on silver. 'money.

Functional silver-based layers range in thickness from 5 to 30nm, 5 to 25nm, or 7 to 16nm.

Preferably, the stack comprises a single functional layer. The stack comprises in this case a single functional layer and two dielectric coatings comprising at least one dielectric layer, so that the functional layer is disposed between two dielectric coatings.

The stack may include at least two metallic silver-based functional layers and at least three dielectric coatings comprising at least one dielectric layer, such that each functional layer is disposed between two dielectric coatings.

The stack is located on at least one side of the transparent substrate.

The stack may include blocking layers located below and / or above the functional silver-based metal layer.

The stack may include at least one blocking layer, the function of which is to protect the silver layers by preventing possible degradation linked to the deposition of a dielectric coating or linked to a heat treatment. These blocking layers are preferably located in contact with the functional silver-based metal layers.

According to advantageous embodiments, the stack may comprise at least one blocking layer, located below and (directly) in contact with a functional silver-based metal layer (under blocking layer) and / or at least one blocking layer located above and (directly) in contact with a functional silver-based metal layer (on blocking layer). A blocking layer on top of a functional silver-based metal layer is called a blocking overcoat. A blocking layer below a functional silver-based metal layer is called a blocking sublayer.

The blocking layers are chosen from metal layers based on a metal or a metal alloy, metal nitride layers, metal oxide layers and metal oxynitride layers of one or more elements chosen from titanium, nickel, chromium, tantalum and niobium such as Ti, TiN, TiOx, Nb, NbN, NbOx, Ni, NiN, NiOx, Cr, CrN, CrOx, NiCr, NiCrN, NiCrOx.

When these blocking layers are deposited in metallic, nitrided or oxynitrided form, these layers may undergo partial or total oxidation depending on their thickness and the nature of the layers which surround them, for example, at the time of deposition of the next layer or by oxidation. in contact with the underlying layer.

The blocking layers can be chosen from metallic layers, in particular of an alloy of nickel and chromium (NiCr) or of titanium.

Advantageously, the blocking layers are metallic layers based on nickel. The nickel-based metal blocking layers can comprise, (before heat treatment), at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of nickel relative to the mass of the metallic base layer nickel.

The nickel-based metal layers can be chosen from:

- metallic layers of nickel,

- metal layers of doped nickel,

- metallic layers based on nickel alloy.

Nickel alloy metal layers can be nickel chromium alloy based.

Each blocking layer has a thickness between 0.1 and 5.0 nm. The thickness of these blocking layers can be:

- at least 0.1 nm, at least 0.2 nm or at least 0.4 nm and / or

- not more than 5.0 nm, not more than 2.0 nm, not more than 1.0 nm or not more than 0.5 nm.

By “dielectric coating” within the meaning of the present invention, it should be understood that there may be a single layer or several layers of different materials inside the coating. A “dielectric coating” according to the invention mainly comprises dielectric layers. However, according to the invention these coatings can also comprise layers of another nature, in particular absorbent layers, for example metallic.

We consider that a "same" dielectric coating is located:

- between the substrate and the first functional layer,

- between each functional silver-based metal layer,

- above the last functional layer (furthest from the substrate).

By "dielectric layer" within the meaning of the present invention, it should be understood that from the point of view of its nature, the material is "non-metallic", that is to say is not a metal. In the context of the invention, this term denotes a material exhibiting an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n denotes the index of actual refraction of the material at a given wavelength and k represents the imaginary part of the refractive index at a given wavelength; the ratio n / k being calculated at a given wavelength identical for n and for k.

The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it.

The dielectric coatings have a thickness greater than 15 nm, preferably between 15 and 200 nm.

The dielectric layers of dielectric coatings exhibit the following characteristics alone or in combination:

- they are deposited by cathodic sputtering assisted by a magnetic field,

- they are chosen from the oxides or nitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin and zinc,

- They have a thickness greater than 2 nm, preferably between 2 and 100 nm.

Preferably, the silver-based functional layer is located above a dielectric layer called a stabilizing or wetting layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally zinc oxide based.

Preferably, the silver-based functional layer is located below a dielectric layer called a stabilizing or wetting layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally zinc oxide based.

The zinc oxide-based layers may comprise, at least 80%, at least 90% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide-based layer, excluding oxygen and nitrogen. The zinc oxide-based layers can comprise one or more elements chosen from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum.

Zinc oxide-based layers can optionally be doped with at least one other element, such as aluminum.

A priori, the zinc oxide-based layer is not nitrided, however traces may exist.

The zinc oxide-based layer comprises, in increasing order of preference, at least 80%, at least 90%, at least 95%, at least 98%, at least 100%, by weight of oxygen relative to the total mass of oxygen.

The dielectric coating located between the substrate and the first functional metallic layer and / or one or each dielectric coating located above the first functional silver-based layer located comprises a zinc oxide-based layer comprising at least 80 % by mass of zinc relative to the mass of all elements other than oxygen.

Preferably, each dielectric coating comprises a zinc oxide-based layer comprising at least 80% by mass of zinc relative to the mass of all elements other than oxygen.

Preferably, the dielectric coating located directly below the functional metal layer based on silver comprises at least one dielectric layer based on zinc oxide, optionally doped with at least one other element, such as aluminum. The metallic functional layer deposited on top of a zinc oxide-based layer is either directly in contact or separated by a blocking layer.

In all stacks, the dielectric coating closest to the substrate is called the bottom coating and the dielectric coating farthest from the substrate is called the top coating. Stacks with more than one silver layer also include intermediate dielectric coatings located between the bottom and top coatings.

Preferably, the lower or intermediate coatings comprise a dielectric layer based on zinc oxide located below and directly in contact with a metallic layer based on silver or separated from this layer by a blocking sublayer. Preferably, the dielectric coating located directly above the functional metal layer based on silver comprises at least one dielectric layer based on zinc oxide, optionally doped with at least one other element, such as aluminum. The metallic functional layer deposited below a zinc oxide-based layer is either directly in contact or separated by a blocking layer.

Preferably, the intermediate or top coatings comprise a zinc oxide-based dielectric layer located above and directly in contact with the silver-based metallic layer or separated from this layer by a blocking overlay.

Zinc oxide layers have a thickness:

- at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm or at least 5.0 nm, and / or

- not more than 25 nm, not more than 10 nm or not more than 8.0 nm.

The dielectric layers can have a barrier function. The term “dielectric layers with a barrier function (hereinafter barrier layer) is understood to mean a layer made of a material capable of forming a barrier to the diffusion of oxygen and water at high temperature, originating from the ambient atmosphere or from the substrate. transparent, towards the functional layer. Such dielectric layers are chosen from the layers:

- based on compounds of silicon and / or aluminum and / or zirconium chosen from oxides such as Si02, nitrides such as silicon nitride Si3N4 and aluminum nitrides AIN, and oxynitrides SiOxNy, optionally doped using at least one other element,

- based on zinc oxide and tin,

- based on titanium oxide.

Preferably, the material comprises one or more layers based on zinc oxide and tin. Zinc and tin oxide layers contain at least 20% by mass of tin based on the total mass of zinc and tin.

The layer based on zinc and tin oxide comprises, with respect to the total mass of zinc and tin, at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 80% by mass of tin.

Preferably, the zinc-tin oxide layer comprises 40-80% by weight of tin based on the total weight of zinc and tin.

The zinc-tin oxide-based layer has a thickness:

- greater than 5 nm, greater than 10 nm, greater than 15 nm, greater than 20 nm or greater than 25 nm,

- less than 50 nm, less than 40 nm or less than 35 nm.

The dielectric coating located between the substrate and the first functional metal layer and / or each dielectric coating located above the first functional silver-based layer located comprises a zinc oxide-based layer and tin comprising at less 20% by mass of tin relative to the total mass of zinc and tin.

Each dielectric coating may include a zinc-tin oxide-based layer comprising at least 20% by mass of tin based on the total mass of zinc and tin.

Preferably, the sum of the thicknesses of all the zinc and tin oxide-based layers located in the dielectric coating located between the substrate and the first silver layer is greater than 30%, greater than 40%, greater 50% or greater than 60% of the total thickness of the dielectric coating.

Preferably, the sum of the thicknesses of all the zinc and tin oxide based layers located in the dielectric coating located above a functional silver based layer is greater than 50%, greater than 60 %, greater than 70% or greater than 75% of the total thickness of the dielectric coating.

Preferably, the sum of the thicknesses of all the oxide-based layers present in the dielectric coating located between the substrate and the first functional metal layer and / or in each dielectric coating located above the first functional layer based on The silver is greater than 50%, greater than 60%, greater than 70%, greater than 80% or greater than 90% of the total thickness of the dielectric coating.

The dielectric coating located between the substrate and the first functional metal layer and / or one or each dielectric coating located above the first silver-based functional layer may consist of an oxide layer only.

Preferably, the stack comprises at least one dielectric layer based on zinc oxide and one layer based on zinc oxide and tin.

Preferably, the dielectric coating located directly below the functional silver-based metal layer has at least one zinc oxide-based dielectric layer and one zinc-tin oxide-based layer.

Preferably, one or each dielectric coating located above the functional metal layer based on silver comprises at least one dielectric layer based on zinc oxide and one layer based on zinc oxide and tin. Preferably, each dielectric coating comprises at least one dielectric layer based on zinc oxide and one layer based on zinc oxide and tin.

The stack of thin layers may optionally include a protective layer. The protective layer is preferably the last layer of the stack, that is to say the layer furthest from the substrate coated with the stack (before heat treatment).

The dielectric coating furthest from the substrate may include a protective layer. These layers generally have a thickness of between 0.5 and 10 nm, preferably 1 and 5 nm.

This protective layer can be chosen from a layer based on titanium, zirconium, hafnium, silicon, zinc and / or tin and their mixture, this or these metals being in metallic, oxidized or nitrided form.

According to one embodiment, the protective layer is based on zirconium and / or titanium oxide, preferably based on zirconium oxide, titanium oxide or titanium and zirconium oxide.

According to one embodiment, the stack comprises:

- a dielectric coating located below the functional silver-based metal layer,

- possibly a blocking layer,

- a functional silver-based metallic layer,

- possibly a blocking layer,

- a dielectric coating located above the functional silver-based metal layer optionally comprising a protective layer.

According to one embodiment, the stack comprises:

- a dielectric coating located below the functional silver-based metallic layer comprising the silicon oxide-based layer, a zinc-tin oxide-based layer, an oxide-based layer zinc,

- possibly a blocking layer,

- a functional silver-based metallic layer,

- possibly a blocking layer,

- a dielectric coating located above the functional silver-based metal layer comprising a zinc oxide-based layer, a zinc-tin oxide-based layer and optionally a protective layer.

The substrate coated with the stack or the stack only may be intended to undergo a heat treatment. The substrate coated with the stack may be curved and / or soaked. However, the present invention also relates to the untreated heat treated coated substrate.

The stack may not have undergone a heat treatment at a temperature above 500 ° C, preferably 300 ° C.

The stack may have undergone heat treatment at a temperature above 300 ° C, preferably 500 ° C.

The heat treatments are chosen from annealing, for example by rapid thermal annealing ("Rapid Thermal Process") such as laser or flash lamp annealing, hardening and / or bending. Rapid thermal annealing is for example described in application WO2008 / 096089.

The heat treatment temperature (at the stack) is greater than 300 ° C, preferably greater than 400 ° C, and better still greater than 500 ° C.

The substrate coated with the stack is preferably a tempered glass, especially when it forms part of a glazing used as a constituent element of a cooling device, of a heating device or of a fire door.

The transparent substrates according to the invention are preferably made of a rigid mineral material, such as glass, or organic based on polymers (or polymer).

The organic transparent substrates according to the invention can also be made of polymer, rigid or flexible. Examples of polymers suitable according to the invention include, in particular:

- polyethylene,

- polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN);

- polyacrylates such as polymethyl methacrylate (PMMA);

- polycarbonates;

- polyurethanes;

- polyamides;

- polyimides;

- fluorinated polymers such as fluoroesters such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene ethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP);

- photocrosslinkable and / or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate resins and

- polythiourethanes. The substrate is preferably a sheet of glass or ceramic glass.

The substrate is preferably transparent, colorless (this is then a clear or extra-clear glass) or colored, for example blue, gray or bronze. The glass is preferably of the soda-lime-silicate type, but it can also be of the borosilicate or alumino-borosilicate type glass.

According to a preferred embodiment, the substrate is made of glass, in particular soda-lime silica, or of polymeric organic material.

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 8 mm, or even between 2.8 and 6 mm. The substrate can be flat or curved, or even flexible.

The invention also relates to a glazing comprising at least one material according to the invention. The invention relates to glazing which may be in the form of monolithic, laminated or multiple glazing, in particular double glazing or triple glazing.

The glazing can be a monolithic glazing comprising 2 faces.

The glazing can be a multiple glazing comprising two, three or four substrates. In this case, the glazing comprises a material according to the invention, comprising in particular a substrate and one, two, three additional substrates.

Multiple glazing comprises at least one material according to the invention and at least one additional substrate. The material and the additional substrate are either side by side or separated by at least one intermediate gas sheet.

Double glazing has two substrates, an exterior substrate and an interior substrate and 4 sides.

A triple glazing has three substrates, an outer substrate, a central substrate and an inner substrate, and 6 sides.

In the case of a building, face 1 is outside the building and therefore constitutes the outer wall of the glazing. All the other faces are numbered successively. The face inside the building has the highest number.

A laminated glazing comprises at least one structure of the first substrate / sheet (s) / second substrate type. The polymeric sheet may in particular be based on polyvinyl butyral PVB, ethylene vinyl acetate EVA, polyethylene terephthalate PET, polyvinyl chloride PVC. The stack of thin layers is positioned on at least one side of one of the substrates.

These glazing can be mounted on a building or a vehicle. These glazings can be mounted on heating or cooling devices such as oven or refrigerator doors.

The glazing may include at least one transparent substrate coated with a functional coating other than a stack comprising at least one functional silver-based metal layer such as a coating comprising a transparent conductive oxide ("TCO"). The coating comprising a transparent conductive oxide can be chosen from a material based on indium tin oxide (ITO), based on zinc oxide doped with aluminum (ZnO: Al) or doped with boron. (ZnO: B), or else based on tin oxide doped with fluorine (SnO 2: F). These materials are deposited chemically, such as for example by chemical vapor deposition (“CVD”), optionally improved by plasma (“PECVD”) or physically, such as for example by vacuum deposition by cathode sputtering, optionally assisted by magnetic field ("Magnetron"). The presence of this other coating is particularly advantageous in the case of a heating device.

The non-stack functional coating comprising at least one functional silver-based metal layer may be on the same substrate. The non-stack functional coating comprising at least one silver-based functional metal layer may be on a different substrate than that coated with a stack comprising a silver-based functional metal layer. In this case the glazing is a multiple glazing.

The glazing can therefore include a functional coating other than a stack comprising a functional silver-based metallic layer such as a coating comprising a transparent conductive oxide located:

- on the substrate comprising a functional silver-based metal layer, on the opposite side to that comprising the functional silver-based metal layer,

- on one side of a substrate different from that comprising a functional silver-based metallic layer.

The heating device allows the enclosure to be heated to a high temperature, in particular greater than 50, 100, 200, 300, 400, 500 or 600 ° C. The heating device further comprises heating means. These heating means allow the enclosure to be heated to a high temperature, in particular greater than 50, 100, 200, 300, 400, 500 or 600 ° C.

The following examples illustrate the invention. Examples Stacks of thin layers defined below are deposited on clear soda-lime glass substrates with a thickness of 4 mm.

For these examples, the conditions for depositing the layers deposited by sputtering (so-called “magnetron cathode sputtering”) are summarized in Table 1 below.

[Table 1] at. : atomic; wt: weight; ^* : at 550 nm. Table 2 below summarizes the conditions for depositing silicon oxide-based layers. [Table 2]

Cpt. : Compartment

The materials Cp-1 to Cp-5 and lnv-1 and lnv-2 comprise a layer of SiO2 deposited in a single zone. For materials lnv-3 and lnv-4, the SiO 2 layer is deposited in two different zones. Table 3 below lists the materials and the physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating which constitutes the stacks as a function of their positions with respect to the substrate carrying the stack. [Table 3] RD: Dielectric coating; CB: Blocking layer; CF: Functional layer

A quench type heat treatment is performed on the coated substrates at 705 ° C for 180 seconds.

Assessment of haze and chemical durability

The level of blur is evaluated as follows. The tempered glass is placed on a desk tilted 20 degrees from the vertical, in a room with black walls. It is lit by a powerful lamp placed vertically over the desk. The observer stands in front of the desk, 1 m away. In this configuration, a fuzzy sample shows a marked milky appearance: it scatters the light from the lamp away from its specular reflection zone on the glass. Conversely, a sample that does not present a blur does not scatter any light in the direction of the observer, so it appears dark. The following assessment indicators were used:

- "-": The material is very blurry, - "0": The material is blurry,

- "+": The material is not blurry.

The chemical durability is evaluated by a high humidity test before (HH) and after heat treatment (TT-HH). The humidity test (HH) consists of storing samples for 56 days at 90% relative humidity and 60 ° C and observing the possible presence of defects such as pitting corrosion. The following assessment indicators were used:

- ok: no pitting, the material does not show any defect after 56 days of testing, - nok: many pitting, the material has defects and therefore does not pass the test.

The results are shown in Table 4 below.

[Table 4] In order to confirm the anti-blur effect photographs and images under the microscope were taken. Figure 1 shows two materials side by side, on the left the material Cp-

1 and on the right the material lnv-2. FIG. 2 groups together two images taken under a microscope, on the left the material Cp-1 and on the right the material lnv-2. Table 5 below summarizes the observations. [Table 5]

In the images of the material of the invention, there is no blurring. This is due to the sharp decrease in the number of dendrites.

Study of the degradation of emissivity as a function of the duration of the heat treatment

Applicant has found that the advantageous properties of the invention from the standpoint of resistance to heat treatments are attributable to a retardation of degradation. The delay is illustrated by the curves in Figure 3. These curves A, B, C, D and E represent the degradation of emissivity in percentage points as a function of the duration of the heat treatment in seconds. The heat treatment is carried out at a temperature of 705 ° C. The Cp-1 materials are compared to the Cp-3 (Curve A), Cp-4 (Curve B), lnv-2 (Curve C), lnv-3 (Curve D) and lnv-4 (Curve E) materials, respectively. The hollowed-out circles represent on each curve Cp-1 and the solid circles represent the element of comparison. The delay is observed when a silicon oxide-based layer of sufficient thickness is used (curves C, D and E).

Table 6 below shows the delay in degradation of the solution of the invention. For this, we compare the duration of the heat treatment in seconds for which we obtain 2 points of degradation of the emissivity between the material Cp-1 and respectively the materials Cp-3 and Cp-4 as well as the materials of the invention lnv-2, lnv-3 and lnv-4.

[Table 6]

For thicknesses less than 12 nm, the delay is too short to be really useful. With at least 12 nm of S1O2, the time / temperature pair during heating becomes compatible with a transformation of the glass, such as tempering or bending without blurring, or degradation of emissivity. On the hardening and bending tools used, the Cp-1 glazing showed a blurring at time and temperature parameters very close to those necessary to obtain an acceptable flatness, a fragmentation, and an acceptable shape. Industrial tools used to bend and / or toughen coated glazing which may exhibit variability. A glazing must therefore be sufficiently robust to accept these process variabilities. The materials lnv-2, lnv-3, and lnv-4 have this added strength.

Claims

1. Material comprising a transparent substrate coated with a stack comprising at least one functional metal layer based on silver and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer or placed between two dielectric coatings, characterized in that the stack comprises a layer based on silicon oxide with a thickness greater than or equal to 12 nm located directly in contact with the substrate.

2. Material according to claim 1 characterized in that the silicon oxide-based layer has a thickness greater than or equal to 14 nm.

3. Material according to any one of the preceding claims, characterized in that the silicon oxide-based layer has a thickness less than or equal to 60 nm.

4. Material according to any one of the preceding claims, characterized in that the dielectric coating located between the substrate and the first functional metal layer and / or one or each dielectric coating located above the first functional layer based on silver has a zinc oxide-based layer comprising at least 80% by mass of zinc relative to the mass of all elements other than oxygen.

5. Material according to any one of the preceding claims, characterized in that the dielectric coating located between the substrate and the first functional metal layer and / or one or each dielectric coating located above the first functional layer based on silver situated comprises a layer based on zinc oxide and tin comprising at least 20% by mass of tin relative to the total mass of zinc and tin.

6. Material according to any one of the preceding claims, characterized in that the stack comprises at least one dielectric layer based on zinc oxide and one layer based on zinc oxide and tin.

7. Material according to any one of the preceding claims, characterized in that each dielectric coating comprises at least one dielectric layer based on zinc oxide and one layer based on zinc oxide and tin.

8. Material according to any one of the preceding claims, characterized in that the sum of the thicknesses of all the oxide-based layers present in the dielectric coating located between the substrate and the first metal layer functional and / or in one or each dielectric coating located above the first functional silver-based layer is greater than 50%, greater than 60%, greater than 70%, greater than 80%, greater than 90% of the total thickness of the dielectric coating.

9. Material according to any one of the preceding claims, characterized in that the dielectric coating located between the substrate and the first functional metal layer and / or one or each dielectric coating located above the first functional layer based on silver consists only of an oxide layer.

10. Material according to any one of the preceding claims, characterized in that all the layers of the stack are deposited by cathodic sputtering assisted by a magnetic field.

11. Material according to any one of the preceding claims, characterized in that the stack comprises:

- a dielectric coating located below the functional silver-based metal layer comprising the silicon oxide-based layer, a zinc-tin oxide-based layer, an oxide-based layer zinc,

- possibly a blocking layer,

- a functional silver-based metallic layer,

- possibly a blocking layer,

12. Material according to any one of the preceding claims, characterized in that the stack comprises a single functional layer.

13. Material according to any one of the preceding claims, characterized in that at least the substrate coated with the stack is curved and / or tempered.

14. Glazing characterized in that it comprises a material according to any one of the preceding claims and one, two or three additional substrates.

15. Glazing according to claim 14, characterized in that it comprises a functional coating other than a stack comprising a functional metallic layer based on silver located:

- on the substrate comprising a functional silver-based metal layer, on the opposite side to that comprising a functional silver-based metal layer,

- on one of the faces of a substrate different from that comprising a functional metallic layer based on silver.

16. Heating or cooling device comprising heating or cooling means and an enclosure delimited by one or more walls, at least one wall of which comprises at least one glazing comprising a material according to any one of claims 1 to 13.

17. Refrigerating device according to claim 16, characterized in that it is of the freezer type and in that the glazing is made of the material and in that the stack is located on the face of the substrate in contact with the enclosure.

18. Use of glazing as a component of a cooling device, a heating device or a fire door, the glazing comprising a material according to any one of claims 1 to 13.

19. A method of preparing a material according to any one of claims 1 to 13 characterized in that all the layers of the stack are deposited by cathodic sputtering assisted by a magnetic field.