Solar protection glazing with two layers based on titanium nitride

Description

[0001] The invention relates to insulating glazing known as solar control glazing, provided with stacks of so-called functional thin layers, i.e. acting on solar and / or thermal radiation essentially by reflection and / or absorption of near (solar) or far (thermal) infrared radiation. The application more particularly targeted by the invention is primarily vehicle glazing, such as side windows, car roofs, rear windows. Without departing from the scope of the invention, the present glazing can also be used in the building sector, as solar control glazing.

[0002] The term "functional" or "active" layer, within the meaning of the present application, means the layers of the stack which give the stack the majority of its thermal insulation properties. Most often, the thin-film stacks equipping the glazing give it significantly improved insulation properties, very essentially through the intrinsic properties of said active layers. Said layers act on the flow of thermal infrared radiation passing through said glazing, as opposed to other layers, generally made of dielectric material and most often having the main function of chemical or mechanical protection of said functional layers. The term "dielectric material" means a material whose massive form, free from impurities, has a high resistivity, in particular an initially higher resistivity than 10 10 < ohms.meters (Ω.m).

[0003] Such glazings equipped with stacks of thin layers act on the incident solar radiation either essentially by the absorption of the incident radiation by the functional layer(s), or essentially by reflection by these same layers.

[0004] They are grouped under the name of solar control glazing. They are marketed and used mainly: either to essentially ensure protection of the passenger compartment (automobile) or the home from solar radiation and prevent overheating, such glazing being qualified in the trade as anti-solar, or essentially to ensure thermal insulation of the home and prevent heat loss, such glazing being qualified as insulating glazing.

[0005] By antisolar, we mean in the sense of the present invention the ability of the glazing to limit the energy flow, in particular the solar infrared radiation (SIR) passing through it from the outside to the inside of the dwelling or passenger compartment.

[0006] Thermal insulation means glazing provided with at least one functional layer providing reduced energy loss, said layer having IR radiation reflection properties of between 5 and 50 micrometers. The functional layers used in this function have a high IR radiation reflection coefficient and are called low-emissive (or low-e according to the English term), see for example US 2018 / 186691 or US 5,091,244.

[0007] In some countries, standards require that glazing have both solar protection and thermal insulation properties for building glazing. In other applications, such as automotive, it is sometimes sought to limit the amount of heat entering the vehicle interior or the building, i.e., to limit the energy transmission of solar radiation through the glazing.

[0008] In general, all the luminous and thermal characteristics presented in this description are obtained according to the principles and methods described in the international standards ISO 9050 (2003) and ISO 10292 (1994), relating respectively to the determination of the luminous and energy characteristics of glazing used in glass for construction. According to another aspect which can also be taken into account in certain applications, when associated with the glass substrate, the coatings must also be aesthetically pleasing, that is to say that the glazing provided with its stack must have a colorimetry, in particular in internal reflection, sufficiently neutral so as not to inconvenience the passengers of the vehicle or the inhabitants of the building in the CIE LAB colorimetry system (L*, a*, b*).In particular, values of the coefficient a* must be close to 0 for the color to be considered sufficiently neutral. In particular, excessively high values of the coefficient a* in internal reflection, i.e. on the stack side (denoted a* c in the rest of the description), reflect an intense coloring of the glazing and should be avoided, particularly in the automotive field. For such a purpose, it will be preferential to seek to obtain glass articles in which the parameter a* c is between -10 and 10, or even between -5 and 5.

[0009] Coatings are conventionally deposited by deposition techniques such as magnetic field-assisted vacuum sputtering of a cathode of the material or a precursor of the material to be deposited, often referred to in the field as magnetron sputtering. Such a technique is now conventionally used, particularly when the coating to be deposited consists of a more complex stack of successive layers with thicknesses of a few nanometers or a few tens of nanometers.

[0010] The most efficient stacks currently marketed to solve the above problems and deposited by magnetron sputtering techniques incorporate a metallic layer of the Silver type operating essentially on the mode of reflection of a major part of the incident IR (infrared) radiation. These stacks are thus used mainly as low-emissivity (or low-e in English) glazing for the thermal insulation of buildings. These layers are however very sensitive to humidity and are therefore exclusively used in double glazing, on face 2 or 3 of the latter, to be protected from humidity. The stacks according to the invention do not include such layers of the silver type, or even of the gold or platinum type or even copper.More generally, the stacks according to the invention do not contain such precious metals, or only in very negligible quantities, particularly in the form of unavoidable impurities.

[0011] The development of new stacks is made necessary by certain specific applications or arrangements.

[0012] Currently, there is a particular demand for glazing that also provides improved visual comfort, particularly in the automotive sector (as side glazing, rear window glazing or even as a glass roof). One of the objects of the present invention to meet such a demand is to provide thermally insulating glazing suitable so that the passengers of the vehicle or the occupants of the building equipped with said glazing are not or only slightly visible from the outside in daylight but can see the outside environment without any discomfort.

[0013] Furthermore, for certain particular applications such as automobiles, an additional object of the invention is to provide glazing meeting the preceding criteria and whose color in internal reflection is relatively neutral, in particular whose coefficient a* in internal reflection (a* c ) is between -10 and 10, or even between -5 and 5.

[0014] According to the results obtained by the applicant company, the preceding problems have been solved by glass articles as now described: According to a first aspect, the present invention relates to a vehicle or building glazing, with solar control properties, comprising at least one glass substrate supporting a stack of layers, in which the stack comprises (or is constituted by) successively from the surface of said substrate: a first module M 1 , constituted by one or more layer(s) based on dielectric materials, of total thickness e 1 , a first layer TN 1 comprising titanium nitride with a thickness of between 5 nanometers (nm) and 35 nanometers, a second module M 2 , consisting of one or more layer(s) based on dielectric materials, with a total thickness e 2 , a second TN 2 layer comprising titanium nitride with a thickness of between 5 nm and 35 nm, a third module M 3 , consisting of one or more layer(s) based on dielectric materials, with a total thickness e 3 , wherein the cumulative sum of the thicknesses of the TN 1 and TN 2 layers comprising titanium nitride is greater than 30 nm, wherein e 1 is less than 30 nanometers, e 2 is between 10 nm and 100 nm, e 3 is greater than 10 nm nanometers and less than or equal to 65 nm, wherein the ratio of the thicknesses e 1 / e 3 is less than 0.6.

[0015] It was discovered that such articles, having in particular a light reflection on the side of the stack of layers (R Lc ) of less than 5% and a difference between the light transmission and the R Lc of less than 30% (the measurement being carried out on a clear monolithic glass on which the stack described above is arranged) effectively made it possible to solve the technical problem described above.

[0016] According to preferred embodiments of the present invention, which can of course be combined with each other where appropriate: The thickness e 2 of the second module M 2 is between 20 nm and 65 nm inclusive, preferably is between 25 nm and 60 nm inclusive. The thickness e 1 of the first module M 1 is less than 25 nm, in particular between 1 nm and 25 nanometers, limits inclusive, preferably between 4 nm and 20 nanometers, limits inclusive. The thickness e 3 of the third module M 3 is between 20 nm and 65 nanometers, inclusive, preferably is between 25 nm and 60 nanometers, inclusive and very preferably is between 30 nm and 50 nanometers, inclusive. The thickness TN 1 of the first layer based on titanium nitride is between 10 nm and 30 nanometers, inclusive, preferably between 15 nm and 25 nanometers inclusive. The thickness TN 2 of the second layer based on titanium nitride is between 10 nm and 30 nanometers, inclusive. The cumulative thickness TN 1 + TN 2 of the first layers based on titanium nitride and second layer based on titanium nitride is less than 60 nm, preferably is less than 55 nm. The ratio of the thicknesses e 1 / e 3 is less than 0.55. The coating does not contain a silver or gold-based layer. The modules M 1 , M 2 and preferably M 3 comprise silicon nitride, in the form of a single layer or a set of layers, at least one of which comprises silicon nitride. M 1 comprises a layer comprising silicon nitride. M 2 comprises a layer comprising silicon nitride. M 3 comprises a layer comprising silicon nitride. The module(s) M 1 , M 2 or M 3 comprise materials selected from silicon nitride, aluminum nitride, tin oxide, mixed zinc and tin oxide, silicon oxide, titanium oxide, silicon oxynitride. M 1 and M 2 are single layers. M 1 and M 2 and M 3 are single layers. M 1 and M 2 are based on silicon nitride. M 1 , M 2 and M 3 are based on silicon nitride.M 2 is a single layer based on silicon nitride or consists essentially of silicon nitride and is in direct contact with the TN 1 and TN 2 layers based on titanium nitride. The glass substrate on which the stack is deposited is made of clear glass. Said coating comprises and preferably consists of the following succession of layers, starting from the surface of the substrate: a first layer M 1 based on silicon nitride with a thickness . e 1 preferably between 1 nm and 25 nm, preferably between 4 nm and 20 nm, a first layer comprising titanium nitride, with a thickness between 10 nm and 30 nanometers, a second layer M 2 based on silicon nitride, with a thickness e 2 between 20 nm and 65 nm, preferably between 25 nm and 60 nm, a second layer comprising titanium nitride, with a thickness between 10 and 30 nanometers, a third single layer M 3 based on silicon nitride with a thicknesse 3 greater than 10 nm, in particular between 20 nm and 65 nanometers, preferably between 25 nm and 60 nm, or a set of dielectric layers M 3 , including at least one layer based on silicon nitride with a thickness greater than 10 nm, in particular between 25 nm and 60 nanometers. The glazing comprises two glass substrates assembled by a thermoplastic sheet, said glazing being provided with said stack of layers, said stack being preferably arranged on the face of a substrate facing an external surface of said glazing. The preceding glazing comprises a first glass substrate, preferably colored in its mass, bonded to a second substrate by an intermediate thermoplastic sheet, in particular made of PVB, said second substrate being made of clear glass and provided with said stack of layers preferably arranged on its face exposed towards the outside of said glazing.By colored in its mass, we mean that the substrate includes in its glass composition elements intended to give it a coloring (i.e. different from that of a so-called "clear" glass), in particular elements such as cobalt, iron, selenium, or even chromium, which may also aim to reduce its light transmission. The said glass substrate(s) are toughened or curved.

[0017] Preferably, the titanium nitride layers are based on titanium nitride or more preferably consist essentially of titanium nitride.

[0018] Titanium-based layers according to the invention comprise, for example, more than 50% by weight of titanium nitride, preferably more than 80% or even more than 90% by weight of titanium nitride.

[0019] The titanium nitride according to the invention is not necessarily stoichiometric (Ti / N atomic ratio of 1) but may be over- or under-stoichiometric. According to an advantageous embodiment, the N / Ti ratio is between 1 and 1.2. Also, the titanium nitride according to the invention may comprise a minor amount of oxygen, for example between 1 and 10 mol% of oxygen, in particular between 1 and 5 mol% of oxygen.

[0020] According to a particularly preferred embodiment, the titanium nitride layers according to the invention correspond to the general formula TiN x O y , in which 1.00 < x < 1.20 and in which 0.01 < y < 0.10.

[0021] The dielectric materials, once deposited in thin layers, may however comprise additional elements substantially increasing their electrical conductivity, useful for example for improving the sputtering efficiency of the precursor material constituting the magnetron target. The dielectric layers of the modules M 1 , M 2 and M 3 according to the invention may be layers based on a material chosen from a silicon nitride, an aluminum nitride, a tin oxide, a mixed oxide of zinc or tin, a silicon oxide, a titanium oxide, a silicon oxynitride. Preferably the modules M 1 , M 2 and M 3 consist of a single layer and this layer is based on silicon nitride or consists essentially of silicon nitride.A material based on silicon nitride, tin oxide, mixed zinc and tin oxide, silicon oxide, titanium oxide, silicon oxynitride is for example a material consisting mainly, for example for more than 50% by weight, preferably for more than 80% or even more than 90% by weight, of such a compound but which may also nevertheless contain other minor elements, in particular as a substitute for the cations, in particular to promote their deposition in the form of thin layers by the usual magnetron sputtering techniques as described above. By way of example, the layers according to the present invention made of silicon nitride or silicon oxynitride, or even silicon oxide, in particular those deposited by magnetron, most often comprise elements of the type Al, Zr, B, etc., in proportions which can go for example up to 10 atomic% or even sometimes up to 20 atomic%, on the basis of the silicon content of the layer. Similarly, the titanium oxide layers can comprise, as a substitute for titanium, other metal cations such as zirconium, without departing from the scope of the present invention. The glazing according to the invention can be a single glazing in which the stack of thin layers is arranged on face 2 of the single glazing by numbering the faces of the substrate from the outside to the inside of the building or the passenger compartment which it equips. According to another embodiment, in particular for use in the automotive field, the glazing according to the invention can be a laminated glazing, comprising two glass substrates assembled by a thermoplastic sheet, said glazing being provided with a stack of layers as described previously.Preferably the stack is deposited on the face of the substrate facing the interior of the building or the living space it equips.

[0022] The substrates and glazings previously described can of course be thermally toughened and / or curved if necessary.

[0023] A method of manufacturing glazing according to the invention comprises, for example, at least the following steps: a glass substrate is introduced into a cathode sputtering device, in a first compartment at least one sub-layer of a dielectric material is deposited, in a subsequent compartment a titanium target is sputtered using a plasma generated from a gas comprising nitrogen, in a subsequent compartment at least one intermediate layer of a dielectric material is deposited, in a subsequent compartment a titanium target is sputtered using a plasma generated from a gas comprising nitrogen, in a subsequent compartment at least one over-layer of a dielectric material is deposited.

[0024] By the terms "underlayer" and "overlayer", reference is made in the present description to the respective position of said layers relative to the functional layer(s) in the stack, said stack being supported by the glass substrate. In particular, when the stack contains a single underlayer and a single overlayer, the underlayer is the layer in contact with the glass substrate and the overlayer is the outermost layer of the stack, facing away from the substrate.

[0025] The term "intermediate layer" refers to the layer(s) arranged between two functional layers.

[0026] For the purposes of the present invention, the term thickness of a layer means the actual geometric thickness of the layer, as it can be measured in particular by conventional electron microscopy or other techniques.

[0027] The invention and its advantages are described in more detail below by means of the non-limiting examples below, according to the invention and comparative examples. In all the examples and the description, unless otherwise specified, the thicknesses given are geometric.

[0028] All substrates are made of 2 mm thick clear glass of the Planiclear type marketed by Saint-Gobain Glass France. All layers are deposited in a known manner by magnetic field-assisted cathode sputtering (often called magnetron).

[0029] As is well known, the different successive layers are deposited in the successive compartments of the cathode sputtering device, each compartment being provided with a specific metal target in Si, Ti, chosen for the deposition of a specific layer of the stack.

[0030] Specifically, silicon nitride layers are deposited in device compartments from a metallic silicon target (doped with 8% by mass of aluminum), in a reactive atmosphere containing nitrogen. The silicon nitride layers therefore also contain aluminum. Titanium nitride layers are deposited in other compartments of the device from a pure metallic titanium target in a reactive atmosphere containing nitrogen and argon.

[0031] The conditions for magnetron deposition of such layers are technically well known in the field.

[0032] In the following examples, the glass substrate was thus successively covered with a stack of layers comprising two functional layers of titanium nitride (denoted for convenience TiN hereinafter even if the actual stoichiometry of the layer is not necessarily this) and sub-layers (first layer M 1 ), over-layers (third layer M 3 ) and intermediate layers (second layer M 2 ) of silicon nitride (denoted for convenience Si 3 N 4 hereinafter even if the actual stoichiometry of the layer is not necessarily this).

[0033] The deposition conditions were adjusted according to conventional techniques for magnetron deposition to obtain different stacks, the succession of layers and their thicknesses (in nanometers nm) of which are shown in Table 1 below: [Table 1] Example If 3 N 4 (M 1 ) TiN (TN 1 ) If 3 N 4 (M 2 ) TiN (TN 2 ) If 3 N 4 (M 3 ) e 1 / e 3 Example 1 (Invention) 15 21 49 29 40 0,37 Example 2 (Invention) 5 21 30 13 26 0,19 Example 3 (Invention) 20 23 54 27 37 0,54 Example 4 (comparative) 39 16 53 35 65 0,60 Example 5 (comparative) 14 20 59 24 8 1,75 Example 6 (comparative) 4 18 35 12 8 0,50 Example 7 (comparative) 38 8 70 21 45 0,85 A-Measurement of glazing characteristics

[0034] The thermal and optical characteristics of the glazing were measured according to the following principles and standards: 1°) Optical properties:

[0035] The measurements are carried out in accordance with the European standard ISO 9050 (2003). Specifically, the light transmission TL and the light reflection on the stack side R Lc are measured between 380 and 780 nm depending on the illuminant D 65.

[0036] The parameter a* c (stack side in internal reflection) is measured according to the colorimetry model (L, a*, b*). 2°) Thermal properties:

[0037] The thermal insulation properties of the glazing are assessed by determining the emissivity at normal incidence ε n measured on the inner face of the substrate covered with the stack of layers, according to the conditions described in standard ISO 10292 (1994), annex A.

[0038] The values of light transmission TL, a* c, reflection R Lc and normal emissivity ε n (in percentages) are measured for the glazing fitted with the stack. B-Results

[0039] The results obtained for monolithic glazing according to the examples described previously are grouped in table 2 below: [Table 2] Example R Lc a* c TL TL - R Lc ε n 1 (inv.) 2 1.5 21 19 <0,35 2 (inv.) 5 3 31 26 <0,35 3 (inv.) 3 -2.1 21 18 <0,35 4 (comp.) 12 0 19 7 <0,35 5 (comp.) 20 4 21 11 < 0,35 6 (comp.) 12 2 32 20 < 0,35 7 (comp.) 3 -14 41 38 <0,35

[0040] It is observed that the single glazings obtained according to the invention (examples 1 to 3) have a very low light reflection (less than 5%) without, however, the light transmission being too high as shown by the relatively small difference between the TL and the R Lc. Such characteristics make such glazings suitable for use allowing unobstructed vision of the exterior of the vehicle for the occupants of the vehicle or of the building equipped with such glazing.

[0041] Examples 4 to 6 show excessive reflection which gives the glazing an undesirable mirror effect in the desired application.

[0042] Example 7 shows a difference between the TL and the R Lc that is too large, which does not guarantee optimal visual comfort, in the sense previously described, particularly in automotive use, as described below. In addition, this high TL is necessarily accompanied by a significant increase in the energy transmission TE, which can lead to very rapid overheating of the passenger compartment in conditions of strong illumination.

[0043] Example 7 also presents a value of its parameter a* c which is too high, which reflects an intense coloration of the glazing visible to the occupants, which is undesirable in certain applications, particularly in the automotive sector.

[0044] According to the following additional examples in which the aim is to obtain glazed roofs for automobiles, the single glazings of examples 1 to 7 are assembled with a glazing colored in its mass and marketed by the applicant company under the reference Venus VG10 ®< (with a TL of approximately 10%), with a thickness of 2 mm. The assembly is obtained by means of a sheet of untinted polyvinyl butyral (PVB) with a thickness of 0.38 mm, such that the stack of layers is found on the outer side of the laminated glazing thus obtained.

[0045] The R Lc and TL parameters are measured on the final laminated glazing as previously described. The results are reported in Table 3 below: [Table 3] Example R Lc a* c TL ε n 1 (inv.) 1 2 6 <0,35 2 (inv.) 4 3.5 9 <0,35 3 (inv.) 3 -2 6 <0,35 4 (comp.) 13 0 5 <0,35 5 (comp.) 20 0 6 < 0,35 6 (comp.) 12 2 9 < 0,35 7 (comp.) 2 -18 12 <0,35

[0046] The optical and energy characteristics of the glazings according to the invention reported in Table 3 are ideal for their use as a glazed roof for a motor vehicle and combine very low TL and R Lc. The use of glazing according to Examples 4 to 6 results in too strong a light reflection. The TL of the glazing of Example 7, for such an application, appears a little too high.

[0047] Just as for monolithic glazing, the laminated glazing according to example 7 also has a value of its parameter a*c that is too high, which results in strong coloration, which is undesirable in certain applications such as the automotive sector.

Claims

1. A vehicle or building glazing having solar control properties comprising at least one glass substrate provided with a stack of layers, in which the stack successively comprises, from the surface of said substrate: - a first module M1 consisting of a layer based on a dielectric material with a thickness t1 or of a set of layers based on dielectric materials with a cumulative thickness t1, - a first layer TN1 comprising titanium nitride, with a thickness of between 5 nanometers and 35 nanometers, - a second module M2 consisting of a layer based on a dielectric material with a thickness t2 or of a set of layers based on dielectric materials with a cumulative thickness t2, - a second layer TN2 comprising titanium nitride, with a thickness of between 5 nanometers and 35 nanometers, - a third module M3 consisting of a layer based on a dielectric material with a thickness t3 or of a set of layers based on dielectric materials with a cumulative thickness t3, in which the cumulative sum of the thicknesses of the TN1 and TN2 layers comprising titanium nitride is greater than 30 nm, in which t1 is less than 30 nanometers, t2 is of between 10 nm and 100 nm and t3 is greater than 10 nanometers and lower or equal to 65 nm, and in which the ratio of the thicknesses t1 / f3 is less than 0.6.

2. The vehicle or building glazing as claimed in claim 1, in which the thickness t2 of the second module M2 is of between 20 nm and 65 nm, limits included.

3. The vehicle or building glazing as claimed in either of the preceding claims, in which the thickness t1 of the first module M1 is of between 1 nm and 25 nanometers, limits included.

4. The vehicle or building glazing as claimed in one of the preceding claims, in which the thickness t3 of the third module M3 is of between 20 nm and 65 nanometers, limits included.

5. The vehicle or building glazing as claimed in one of the preceding claims, in which the thickness TN1 of the first layer based on titanium nitride is of between 10 nm and 30 nanometers, limits included.

6. The vehicle or building glazing as claimed in one of the preceding claims, in which the thickness TN2 of the second layer based on titanium nitride is of between 10 nm and 30 nanometers, limits included.

7. The vehicle or building glazing as claimed in one of the preceding claims, in which the ratio of the thicknesses t1 / f3 is less than 0.55.

8. The vehicle or building glazing as claimed in one of the preceding claims, in which the coating does not contain a layer based on silver or on gold.

9. The vehicle or building glazing as claimed in one of the preceding claims, in which the module(s) M1, M2 or M3 comprise materials chosen from a silicon nitride, an aluminum nitride, a tin oxide, a mixed zinc tin oxide, a silicon oxide, a titanium oxide or a silicon oxynitride.

10. The vehicle or building glazing as claimed in one of the preceding claims, in which said first module, said second module and said third module all comprise a layer comprising silicon nitride and preferably consist of a single layer comprising silicon nitride.

11. The vehicle or building glazing as claimed in one of the preceding claims, in which M1 and M2 are single layers.

12. The vehicle or building glazing as claimed in one of the preceding claims, in which M1 and M2 are based on silicon nitride.

13. The vehicle or building glazing as claimed in one of the preceding claims, in which the glass substrate is made of clear glass.

14. The vehicle or building glazing as claimed in one of the preceding claims, in which said coating comprises and preferably consists of the sequence of following layers, starting from the surface of the substrate: - a first layer M1 based on silicon nitride, with a thickness t1 preferably of between 1 nm and 25 nm, - a first layer comprising titanium nitride, with a thickness of between 10 nm and 30 nanometers, - a second layer M2 based on silicon nitride, with a thickness t2 of between 20 nm and 65 nm, - a second layer comprising titanium nitride, with a thickness of between 10 and 30 nanometers, - a third single layer M3 based on silicon nitride, with a thickness t3 of greater than 10 nm, in particular of between 20 nm and 65 nanometers, or a set of dielectric layers M3, including at least one layer based on silicon nitride with a thickness of greater than 10 nm, in particular of between 25 nanometers and 60 nanometers.

15. The vehicle or building glazing as claimed in one of the preceding claims, comprising two glass substrates assembled by a thermoplastic sheet, said glazing being provided with said stack of layers, said stack preferably being positioned on the face of a substrate facing an exterior surface of said glazing.

16. The vehicle or building glazing as claimed in the preceding claim, comprising a first glass substrate, preferably colored in its bulk, bonded to a second substrate by an intermediate thermoplastic sheet, in particular made of PVB, said second substrate being made of clear glass and provided with said stack of layers preferably positioned on its face exposed toward the outside of said article.

17. The vehicle or building glazing as claimed in one of the preceding claims, in which said glass substrate(s) are tempered or bent.