Glazing having hydrophobic properties by the gaseous release of hydrophobic compounds contained in an emitter

Abstract

The present invention relates to glazing comprising a transparent substrate, characterised in that it comprises, at the periphery of the substrate, at least one emitter of hydrophobic compounds by a gaseous process; said at least one emitter being arranged to enable the release of said hydrophobic compounds, and a fraction of said released hydrophobic compounds being able to be deposited on the surface of said transparent substrate. The present invention also relates to the use of this glazing as described above as rain-proof glazing, said rain-proof glazing being able to be used as glazing in buildings, land-, air- or water-based vehicles, or urban furniture, preferably as aircraft cockpit glazing. The present invention also relates to a method for hydrophobising glazing as described above.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: Glazing with hydrophobic properties by gaseous release of hydrophobic compounds contained in an emitter

[0003] The present invention relates to a glazing comprising a transparent substrate, in particular a glass article, the external surface of which has been made hydrophobic by gaseous release of hydrophobic compounds contained in an emitter placed on the periphery of said substrate. The invention relates in particular to rain-proof glazing for buildings, land, air or water vehicles, or street furniture.

[0004] Hydrophobic properties are sought for windows and windshields in the transport sector, particularly for motor vehicles and aircraft, as well as for glazing in the building sector. For applications in the transport sector, rain-repellent properties are sought, as water collected by the glazing and the areas upstream of the vehicle must easily flow off the glass wall in the form of drops or streams, for example when moving under the effect of air and wind, in order to improve visibility and, consequently, safety, or to facilitate cleaning, easily remove frost, etc.

[0005] To this end, a contact angle of a water droplet with the substrate is sought which is greater than 60° or 70° and preferably greater than 90°, the water droplet not having to crush or spread until continuous films are formed. Indeed, a glazing is said to be functional as long as this angle is greater than 60° for aeronautics and 70° for automobiles. To make a glass substrate hydrophobic, it is known to deposit on its external surface, grafted hydrophobic compounds of the fluorinated silane type, as described in US patent application 4,983,459.It is also known to cover the glass with a mineral layer serving as a primer in order to graft said fluorinated silane molecules, said mineral layer being a dense silica layer such as that described in patent EP 0545201, or a sol-gel silica layer such as that described in patent EP 799873, or even a silicon layer in the activated state such as that described in patent application WO 2005 / 084943. However, these hydrophobic coatings by grafting fluorinated silanes onto the external surface of a glass substrate present risks to health and the environment due to the fluorinated compounds; which are also under threat of regulatory limitations. In addition, these coatings tend to degrade over time due to the attacks that the glazing is constantly subjected to, such as: hydrolysis, photodegradation, sensitivity to the impacts of atmospheric dust, sensitivity to electrostatic discharges, etc.Thus, these hydrophobic fluorinated silane coatings have short lifetimes, particularly in flight, for example of the order of 6 months when deposited on the windshield of a short-haul commercial aircraft. It would be possible to increase the thickness of the hydrophobic coating on the surface of the glazing in order to increase their lifespan. This strategy is also implemented in the case of hydrophobic varnishes. However, these coatings are sensitive to scratches; this would also limit their lifespan and the general optical quality of the glazing would also be degraded. In addition, these visible scratches are generally not repairable and may require the glazing to be replaced. Therefore, coatings with thick functionalization (>100 nm) should not be considered to solve the aforementioned problems.

[0006] Furthermore, the loss of performance of coatings of grafted hydrophobic compounds of the fluorinated silane type is difficult to predict since, as stated above, it strongly depends on climatic and atmospheric conditions (exposure to dust, events leading to surface electrostatic discharges, saline environment, etc.). In particular, solutions based on fluorinated silanes used on aeronautical glazing present a significant regeneration complexity. Indeed, the maintenance of such glazing requires an intervention sheltered from the rain with good access to the glazing, as well as good lighting to guarantee good final optical quality, and heating systems improving the fixation of the fluorinated silanes. This also requires the availability of a hangar and often leads to the temporary cessation of commercial operation of an aircraft.In addition, chemicals are used by specially trained operators and the short lifetime of the reagents prepared by these operators makes the processes sensitive to the vagaries of deposition as well as to ambient temperatures. In other words, poor control of deposition conditions can lead to a shortened lifetime of the hydrophobic functionalization of regenerated fluorinated silanes.

[0007] In conclusion, these fluorinated silane solutions degrade easily over time and generate maintenance costs, logistical complexities and degradations in the commercial availability of aircraft for airlines. The inventors therefore sought to develop a glazing comprising a transparent substrate, preferably a glazing for an air vehicle such as an airplane, having continuous hydrophobic properties and for which the regeneration of the hydrophobic properties of said substrate is simple to implement. Advantageously, the inventors sought to provide a glazing having improved hydrophobic properties, in particular in their durability and predictability, while retaining other properties such as resistance to mechanical stresses (resistance to friction, abrasion, and wiping, etc.); resistance to climatic stresses (resistance to UVA and UVB rays, neutral salt spray, acid rain, etc.)); and the preservation of optical properties, in particular when the glazing is a glass article. Even more preferably, the inventors have sought to use volatile hydrophobic compounds so that they can be applied continuously to the external surface of the transparent substrate of a glazing, without maintenance intervention, in other words by continuous regeneration of the hydrophobic functions on the surface of said substrate.

[0008] The inventors have thus proposed that the hydrophobic compounds are transported by gas directly from an emitter located at the periphery of the transparent substrate of a glazing unit to the external surface of said substrate. Thus, the object of the present invention is to provide a glazing unit (1) comprising a transparent substrate (S), of which said glazing unit comprises, at the periphery of the substrate, at least one emitter (2) of hydrophobic compounds by gas; said at least one emitter being arranged to allow a release of said hydrophobic compounds, and a fraction of said released hydrophobic compounds being capable of being deposited on the surface of said transparent substrate.

[0009] Indeed, it was surprisingly found by the inventors that the gaseous release of hydrophobic compounds contained in at least one emitter located on the periphery of a transparent substrate of a glazing unit made it possible to make the external surface of said substrate hydrophobic. It was further observed that this hydrophobic performance is maintained over time; as long as the balance of the flows of hydrophobic compounds, between on the one hand those arriving on the surface and coming from the emitter or the environment and, on the other hand those leaving for various reasons already mentioned (such as hydrolysis, evaporation, erosion, etc.) allows the persistence of a sufficient quantity of hydrophobic compounds which can be approximated to a fraction of a molecular monolayer of hydrophobic compounds.Maintaining a sufficient quantity of hydrophobic compounds on the surface of the transparent substrate is thus improved according to the invention, by generating a flow of hydrophobic compounds emitted by the emitter, and adding to the natural flows, and / or by a specifically strong affinity between the surface of the substrate and the hydrophobic compounds. By this mechanism, the emitters associated with the air flows on the surface of the transparent substrate continuously ensure the regeneration of the surface with hydrophobic compounds and therefore an improved hydrophobic performance of the substrate. If necessary, regeneration of the emitters may be required either by replacing them or by recharging them with hydrophobic compounds.

[0010] The invention is illustrated using the following non-limiting figures:

[0011] - Figure 1 (Fig. 1) schematically represents a glazing (1) according to the invention;

[0012] - Figures 2 (Fig. 2) and 3 (Fig. 3) schematically represent a glazing (1) according to the invention each comprising an example of substrate (S) and an emitter (2), the emitter (2) comprising in the two figures at least one reservoir (20) in the form of a solid serving as an emitting surface;

[0013] - Figure 4 (Fig. 4) schematically represents a glazing (1) according to the invention in which the emitter (2) comprises a reservoir (20') and an emitting surface (21);

[0014] - Figures 5a (Fig. 5a) and 5b (Fig. 5b) schematically represent a glazing (1) comprising an emitter (2) which comprises a reservoir (20') and an emitting surface (21) in the form of a membrane (210) or a plate provided with at least one opening (212) respectively;

[0015] - Figure 6 (Fig.6) schematically represents an example of glazing (1) according to the invention;

[0016] - Figures 7 (Fig. 7) and 8 (Fig. 8) schematically represent a glazing (1) according to the invention comprising a frame (3) in which the transparent substrate (S) is mounted, and the emitter (2) is arranged at the level of the frame (3).

[0017] The transparent substrate (S) of a glazing (1) according to the invention may comprise:

[0018] - a ply of a material chosen from the list comprising glass, glass-ceramic, polymer, as shown in figure 2, or

[0019] - a laminated assembly of at least two plies (S1, S2), said plies being made of an identical or different material, said material being chosen from the list comprising glass, glass-ceramic, polymer, as shown in figure 3.

[0020] According to the invention, the term "glass" means a mineral glass, in particular of the soda-lime-silica, borosilicate or aluminosilicate type. The polymer may be chosen from polycarbonate (PC), poly(methyl methacrylate) (PMMA), polyurethane (PU) and polyethylene terephthalate (PET).

[0021] In the case of a laminated assembly, the plies (S1, S2) are laminated or assembled by means of an interlayer (S3). This interlayer (S3) may comprise one or more adhesive layers made of a polymeric material. Said polymeric material is preferably chosen from thermoplastic polyurethane (TPU), poly(vinyl butyral) (PVB), poly(ethylene-vinyl acetate) (EVA), silicones and ionomer resins. Several adhesive layers of different natures may be used on the same glazing between two pairs of successive or different plies and between the same pair of successive plies.

[0022] In a preferred embodiment, the glazing (1) is a laminated glazing whose substrate (S) comprises at least two plies (S1, S2) of glass glued or assembled by means of intermediate adhesive layers (S3) of the thermoplastic polyurethane, poly(vinyl butyral) or poly(ethylene-vinyl acetate) type.

[0023] In another preferred embodiment, the glazing is a laminated glazing whose substrate comprises at least one ply of poly(methyl methacrylate) (PMMA), preferably at least two plies of PMMA glued or assembled by means of intermediate adhesive layers as mentioned above.

[0024] In yet another preferred embodiment, the glazing is a laminated glazing whose substrate comprises at least one polycarbonate (PC) ply, preferably at least two PC plies glued or assembled by means of intermediate adhesive layers as mentioned above.

[0025] But other designs are possible, such as glazing comprising at least one layer of polyethylene terephthalate (PET) and an adhesive layer of thermoplastic polyurethane (TPU) or polyvinyl butyral (PVB).

[0026] In the present invention, the glazing (1) comprises a transparent substrate (S) and at least one emitter (2) of hydrophobic compounds by gaseous means which is positioned at the periphery of said transparent substrate, as can be seen in Figures 1 and 2. In the present application, the term "emitter" means a gas diffusion system. The emitter is therefore intended to produce / emit gases and to supply them to the transparent substrate and in particular to supply them to the layer capable of adsorbing the hydrophobic compounds. In the present application, the term "periphery" means the zone corresponding to the connection or the interface between the transparent substrate and the structure on which the substrate is placed, either on the substrate side or on the structure side, and preferably upstream of the air flows.It is also possible to move away from this zone (boundary) by being limited by the visibility zone on the substrate side and to extend even further upstream of the air flows on the structure side. However, positioning in close proximity to the transparent substrate, particularly in the lower part of the glazing, is preferred. This positioning is particularly advantageous in the case where the structure is that of a vehicle since it makes it possible to improve the efficiency of use of the hydrophobic compounds since one takes advantage of the air flow on the surface of the substrate (most often induced by the speed of the vehicle) to sweep the surface of air loaded with hydrophobic compounds.

[0027] More specifically, in the case of glazing of an air vehicle, the transmitter is positioned in the glazing-aircraft interface zone, either on the glazing side or on the aircraft side and upstream of the air flows sweeping the glazing in flight conditions.

[0028] In a first configuration of the invention, the glazing comprises an emitter which extends over the entire periphery of the substrate.

[0029] In a second configuration of the invention, the glazing comprises at least two emitters arranged to extend over the entire periphery of the substrate.

[0030] In a third configuration of the invention, the glazing comprises one or at least two emitters on the periphery of said substrate but which do not extend over the entire periphery of the substrate.

[0031] The emitter according to the invention may have a linear geometry, for example in the form of a strip or a slot, or may consist of several point emission sites, for example in the form of holes. Furthermore, the emitter may be integrated into the transparent substrate or integrated into the structure supporting the transparent substrate.

[0032] In a first embodiment, said emitter (2) according to the invention comprises at least one reservoir (20) in the form of a solid serving as an emitting surface, as seen in Figures 2 and 3.

[0033] Said reservoir (20) can then be flush and / or uneven with the surface of the transparent substrate of the glazing, and can comprise:

[0034] - according to a first variant, at least one pure hydrophobic compound or several hydrophobic compounds in a mixture, preferably in solid form. According to this variant, the emission of the hydrophobic compounds is carried out by sublimation on the external surface of the substrate, i.e. on the surface of the substrate exposed to the air, the emission being able to be amplified by the convections of the air; or

[0035] - according to a second variant, at least one hydrophobic compound solubilized and / or dispersed in a polymer matrix. The polymer matrix may comprise a polymer chosen from polysulfides, epoxies, polyurethanes, silicones and rubbers. According to this variant, the hydrophobic compound(s) solubilized and / or dispersed in said polymer matrix are in the form of solid grains or droplets which diffuse in said matrix, then the hydrophobic compounds are desorbed and emitted in the gas phase on the external surface of the substrate. The polymer matrix makes it possible to protect the hydrophobic compounds which, without encapsulation by said matrix, could at least under certain conditions of use flow when they are in the liquid state at high operating temperatures. The polymer matrix also makes it possible to protect the hydrophobic compounds from dissolution by certain fluids, by erosion, by rain or dust, or

[0036] - according to a third variant, at least one hydrophobic compound integrated into a porous matrix, in other words the hydrophobic compound(s) filling the porosities of the porous matrix. The porous matrix may be metallic, ceramic or sintered glass. Optionally, the porous matrix may consist essentially of a polymer and be in the form of a sponge or a seal, for example. Said porous matrix may have open porosity. Advantageously, the pore size of said matrix is ​​between 1 μm and 0.1 mm in order to prevent the penetration of rainwater into the tank. This porous matrix with open porosity physically separates the tank from the outside air and allows the diffusion of the hydrophobic compounds through said open pores. This is followed by desorption and then remission in the gas phase of the hydrophobic compounds towards the external surface of the substrate.The hydrophobic compounds filling the open pores of the matrix are in the liquid or solid state.

[0037] In a second embodiment, said emitter (2) according to the invention comprises a reservoir (20') and an emitting surface (21), said reservoir (20') being a volume communicating with said emitting surface (21), as can be seen in Figure 4. In other words, in this second embodiment, the reservoir (20') and the emitting surface (21) of the emitter (2) are dissociated. The volume of said reservoir can then comprise at least one hydrophobic compound located:

[0038] - in solid form, or

[0039] - in liquid form, or - solubilized and / or dispersed in a polymer matrix, or

[0040] - integrated into a porous matrix.

[0041] In the particular case of a reservoir (20') comprising at least one hydrophobic compound in liquid form, said reservoir may further comprise compounds without hydrophobic properties such as solvents or solid fillers. Where appropriate, elements such as fibers or powders or porous particles may be added to the reservoir to prevent the flow of the liquid compounds by capillary mechanisms. The reservoir (20') is thus designed to allow the transport of the hydrophobic compounds in liquid form by direct contact, towards the emitting surface (21) which is flush with the outer surface of the substrate.

[0042] In the particular cases where the reservoir (20') comprises at least one hydrophobic compound in solid form, solubilized and / or dispersed in a polymer matrix, or integrated in a porous matrix, the gas phase emissions of the hydrophobic compounds towards the external surface of the substrate are carried out by the emitting surface (21) and as mentioned in the first embodiment.

[0043] The emitting surface (21), according to the invention, may comprise:

[0044] - at least one membrane (210), and / or

[0045] - at least one plate provided with at least one opening (212).

[0046] According to a first alternative, the emitting surface (21) comprises at least one membrane (210), as shown in Figure 5a. The membrane according to the invention may be essentially made of at least one polymer chosen from polysulfides, polyurethanes, polyvinyl chlorides, and rubbers. The membrane is advantageously solid; it may thus be a permeation membrane. The use of a membrane as an emitting surface allows the emission of hydrophobic compounds by absorption on the reservoir side, then diffusion in the membrane then desorption and emission of said hydrophobic compounds in the gas phase on the face exposed to the outside air of the substrate (called the external face or outer face of the substrate), which has the advantage of better controlling or regulating the release in the gas phase of the hydrophobic compounds towards the external surface of the substrate.

[0047] According to a second alternative, the emitting surface (21) comprises at least one plate provided with at least one opening (212), as shown in figure 5b or in figure 6. This plate can be a metal plate pierced by one or more slots or by a multitude of holes. These slots or these openings can all be identical or there can be openings or slots of different sizes, shapes.

[0048] According to a third alternative, the emitting surface (21) comprises at least one membrane (210) according to the first alternative and at least one plate (212) according to the second alternative.

[0049] Furthermore, the emitter (2) may comprise a protective layer for the emitting surface (21), said protective layer being made of a porous material. The porous material is a material chosen from ceramics, metal foams, sintered glasses and polymeric foams.

[0050] In the particular case where the emitting surface (21) comprises at least one membrane (210) or one membrane (210) and a plate provided with at least one opening (212), said porous material is placed above the membrane, which itself may, if necessary, cover the openings of the plate. This protective layer then has the purpose of protecting the membrane from the abrasive external environment, and this without hindering the gaseous transport of the hydrophobic compounds.

[0051] In another particular case, when the emitting surface (21) comprises at least one plate provided with at least one opening (212), said porous material can cover said openings of the plate, being able to serve as a “plug” for filling with hydrophobic compounds. The filling can be done with liquid hydrophobic compounds by pouring them directly into the porous material (which can have the function of a wick). The plug(s) can then be accessible without having to remove the glazing.

[0052] In a preferred embodiment of the invention, when the reservoir (20') comprises at least one hydrophobic compound in liquid form, said emitter (2) may further comprise at least one channel (22) connecting the emitting surface to the reservoir, as shown in Figure 8. This allows the emitter to include a larger reservoir in order to be able to store a larger quantity of liquid hydrophobic compounds.

[0053] According to this embodiment, the emitter may also comprise a diffusion means for supplying the entire emitting surface. This diffusion means may, for example, take the form of a cavity to which the entire emitting surface and the channel are connected.

[0054] According to the second embodiment, the emitting surface (21) can extend particularly over the entire periphery of the transparent substrate, and more preferably over all or part of the length of the lower upright of the glazing (1) with a width of up to 3 cm. This emitting surface can also be partially up to one millionth of its surface in the case of emission by a few thin holes having a diameter of between 0.05 mm and 2 mm.

[0055] According to the first and second particular embodiments mentioned above, the reservoir (20) or (20') may be in the form of a profile or a bulb or a parallelepiped or any other shape. The reservoir may be essentially made of a material chosen from elastomers such as rubber, thermoplastic polymers such as polyvinyl chloride, or metals such as steel or aluminum.

[0056] More particularly, the emitter according to the invention also provides the function of peripheral seal of a glazing commonly called "drop". The drop is in fact known to provide the glazing with aerodynamic continuity between glazing and mounting structure (such as the structure of an aircraft), as well as good inertia to treatment fluids (such as aeronautical fluids, cleaning products, degreaser, glycol for ground de-icing and the like); this drop can be made of polysulfide or equivalent.

[0057] According to the present invention, the glazing (1) may further comprise at least one heating means. The heating means(s) are preferably located in or around the emitter (2) so as to allow heating by thermal conduction: of the reservoir (20) or (20'), of the emitting surface (21) and, where appropriate, of any elements allowing the transport of the hydrophobic compounds from the reservoir to the emitting surface, such as channels (22) or tubes. The heating may be obtained by means of resistive wires, or resistive layers. The heating means(s) may in particular be placed directly opposite the emitter. Alternatively, the heating means may be positioned in the transparent substrate (S) of the glazing (1). In the case of a laminated assembly, the heating means is placed inside the laminate, preferably in contact with the glass fold located towards the outside.Said heating means may be in the form of a transparent conductive layer, typically based on ITO or based on copper, nickel, iron and nickel alloy, or tungsten wires having a diameter of between 20 pm and 40 pm.

[0058] In the case of glazing for aerial vehicles, heating means are very useful. Indeed, convection and low pressures in flight conditions significantly accelerate the evaporation of hydrophobic compounds compared to ground conditions. But, conversely, the low temperatures encountered in flight significantly lower the partial pressures of hydrophobic compounds and therefore the molecular flows by gaseous means. This is why heating means make it possible to optimize the preferential emission of hydrophobic compounds in the flight phases which tend to carry the compounds towards the glazing, compared to the emissions of hydrophobic compounds when the aerial vehicle is on the ground.

[0059] Additionally, heating means can help prevent the transmitter from becoming blocked by frost.

[0060] According to the present invention, the glazing (1) may further comprise a frame (3) in which the transparent substrate (S) is mounted. The frame (3) may be a metal profile or a polymer seal.

[0061] In the case of vehicle glazing, the frame is either an integral part of the vehicle, or the frame is, as mentioned above, an element in which the substrate is mounted and thus the assembly formed by the frame and the transparent substrate is then mounted in the vehicle.

[0062] According to a preferred embodiment, the frame (3) is used for the arrangement of the emitter (2). Indeed, the frame (3) can be arranged to carry the emitter (2), as can be seen in figures 7 and 8 or be arranged so that the emitter is placed at the interface between the substrate and the frame.

[0063] As mentioned previously, the glazing (1), according to the invention, comprises a transparent substrate (S) and at least one emitter (2) of hydrophobic compounds by gaseous means positioned at the periphery of the substrate; said at least one emitter being arranged to allow a release of said hydrophobic compounds, and a fraction of said released hydrophobic compounds being capable of being deposited on the surface of said transparent substrate. In the present application, the term "by gaseous means" means that the hydrophobic compounds are transported between the emitter and the glazing in gaseous molecular form, subject to the phenomena of entrainment by air flows and diffusion in a gaseous medium. As described above, the emitter may comprise pure hydrophobic compounds or diluted hydrophobic compounds in cases where these hydrophobic compounds are solubilized and / or dispersed in a polymer matrix or integrated into a porous matrix.Then, said hydrophobic compounds are: either directly exposed to the air (when the emitter comprises a reservoir in the form of a solid serving as an emitting surface), or transported to an emitting surface such as a membrane or a plate provided with openings (when the emitter comprises a reservoir and an emitting surface). Geometrically, the emission surface of the hydrophobic compounds can therefore take a multitude of forms. In the case of continuous emission or in a multitude of emitting zones along the uprights of a glazing, the emitting surface can be likened to an equivalent band characterized by an equivalent slot width generating the same flow of contaminants. As a result, the emitting surface generates a flow of hydrophobic compounds equal to or less than the flow that the same surface consisting essentially of pure compounds would emit.For example, an emitting surface comprising a 20 mm opening associated with a product diluted to 10% is equivalent to an emitting surface with a 2 mm opening for a pure compound. The person skilled in the art therefore knows that the fluxes of hydrophobic compounds must be weighted in relation to the emission surface, at the dilution rate.

[0064] Furthermore, the emitting surface may be a strip placed on the periphery of the transparent substrate of a glazing or one or more fractions (or piece(s)) placed on the periphery of the substrate, which also varies the vapor pressure of the hydrophobic compounds of the emitter. The person skilled in the art will integrate this variable and adapt each of the cases in order to obtain the correct partial vapor pressure allowing the hydrophobic compounds to be released.

[0065] Thus, the hydrophobic compounds of the emitter, according to the invention, preferably have a vapor pressure of between 10' 8Pa and 1 Pa, more preferably between 10' 8 Pa and 10' 6 Pa for emitters with a large emission surface between 10 mm and 30 mm, and advantageously between 10' 2 Pa and 1 Pa for emitters with a small emission surface between 10 pm and 3 mm. These partial pressures are defined at a temperature between 20°C and 30°C, more preferably at a temperature equal to 25°C. This low vapor pressure adapted to the emission surface allows the hydrophobic compounds to be evaporated in quantities high enough to allow functionalization of the transparent substrate while being limited to minimize the consumption of hydrophobic compounds.

[0066] Once the hydrophobic compounds are emitted by the emitter by gaseous means, the hydrophobic compounds are integrated into the air flow which flows parallel to the transparent substrate of the glazing. In this air flow, the hydrophobic compounds can diffuse and in particular in the directions normal to the surface of the glazing, which causes some of the compounds to move away from the glazing and be lost, while some are redirected towards the external surface of the transparent substrate on which they can be adsorbed. Thus, some or a fraction of the hydrophobic compounds released by the emitter condense on the surface of the glazing, giving it hydrophobic characteristics.

[0067] The hydrophobic compounds of the emitter, according to the invention, are preferably chosen from:

[0068] (a) a carboxylic acid of formula (I): R-COOH in which R represents a linear, branched or cyclic, saturated or unsaturated, C4-C22 alkyl group, preferably R is an alkyl group of formula (A): CnH2n+i, in which n is between 6 and 20, or

[0069] (b) a phosphate of formula (II): RO-PO(OH)2 in which R represents a linear, branched or cyclic, saturated or unsaturated, C4-C22 alkyl group, preferably R is an alkyl group of formula (A): CnH2n+i, in which n is between 6 and 20, or

[0070] (c) a phosphonic acid of formula (III): R-PO(OR')(OR”) in which R, R' and R” represent a hydrogen atom, an alkyl group or an aryl group, C4-C22, preferably R, R' and R” are alkyl groups of formula (A): CnH2n+i, in which n is between 6 and 20, or

[0071] (d) a silicone,

[0072] (e) a paraffin, or

[0073] (f) a mixture of these.

[0074] More preferably, the hydrophobic compounds are chosen from carboxylic acids of formula (IA): CnH2n+i-COOH, in which n is between 7 and 19. In the particular case of a large emission surface, the preferred carboxylic acid is stearic acid (n is equal to 17) since this hydrophobic compound has the advantage of being inexpensive, without risk to health or the environment and is sufficiently volatile. And in the particular case of a small emission surface, for example obtained by openings by a plate pierced with openings of 0.1 mm in diameter spaced apart by a few millimeters and aligned parallel to the edge of the glazing, the preferred carboxylic acid is decanoic acid (n is equal to 9) since this hydrophobic compound has the advantage of being liquid which allows easy refilling of the tank while remaining a safe and inexpensive compound. In fact, the inventors chose hydrophobic compounds which are:

[0075] - sufficiently volatile to be able to evaporate, vaporize or sublimate easily,

[0076] - chemically stable to avoid polymerization reactions, and

[0077] - resistant to climatic or atmospheric conditions, such as oxidation, UV, neutral salt spray, etc.

[0078] The transparent substrate (S) of the glazing (1) may further comprise on its external face at least one layer capable of adsorbing hydrophobic compounds. For the purposes of the present invention, the external (or "external") face corresponds to the face of the transparent substrate facing the exterior of a building or a vehicle.

[0079] The layer capable of adsorbing hydrophobic compounds may comprise:

[0080] - at least one oxide or nitride of a lanthanide, or an alloy of at least two lanthanides, the lanthanide being chosen from the list comprising lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or

[0081] - at least one oxide or nitride of a metal or an alloy of at least two metals, the metal being chosen from the list comprising scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), or

[0082] - at least one oxide or nitride of an alloy comprising a lanthanide and a metal chosen from the above-mentioned lists.

[0083] Advantageously, the layer capable of adsorbing hydrophobic compounds consists essentially of a material chosen from cerium oxide (CeOx), gadolimium oxide (Gd), yttrium oxide (YOx), titanium oxide (TiOx), zirconium oxide (ZrOx) or hafnium oxide (HfOx).

[0084] And, as an example as an alloy, we can cite the following mixed oxides, such as TiYOx, HfYOx, HfZrOx, ZrYOx or GdYOx.

[0085] Furthermore, it should be noted that the layers capable of adsorbing hydrophobic compounds according to the invention are deposited on the external face of the transparent substrate by a physical vapor phase (PVD) or chemical vapor phase (CVD) process, such as sputtering, or by evaporation or by atomic layer deposition (ALD) or alternatively by a liquid route of the sol-gel type. The layers capable of adsorbing compounds may have a thickness of between 5 and 1000 nm, preferably between 6 and 200 nm, and more preferably between 7 and 30 nm.

[0086] The inventors found that at least one layer capable of adsorbing hydrophobic compounds placed on the external face of the substrate made it possible to promote the adsorption of hydrophobic compounds after diffusion and transport of these compounds thanks to air flows.

[0087] The transparent substrate may further comprise on its external face at least one additional layer which does not have the function of adsorbing volatile hydrophobic compounds. For example, said additional layer may have electrical dissipative properties. Said additional layer may be placed above or below said at least one layer capable of adsorbing hydrophobic compounds. Said additional layer is preferably essentially made of a material chosen from tin oxide or indium-tin oxide.

[0088] The glazing (1) according to the invention is advantageously used as rain-proof glazing, and even more advantageously as glazing for buildings, land, air or water vehicles, or street furniture, preferably as glazing for the cockpit of an air vehicle.

[0089] The present application also relates to a method for hydrophobizing a glazing (1) as described above comprising the following steps:

[0090] - gaseous release of hydrophobic compounds from the emitter (2) at a pressure ranging from 2.10 4 Pa at 10 5 Pa,

[0091] - depositing on the transparent substrate a fraction of said hydrophobic compounds released using a flow or stream of air flowing parallel to said transparent substrate and at a speed of at least 70 meters per second.

[0092] During the process, a fraction of the hydrophobic compounds released by the emitter condense on the surface of the glazing, giving it hydrophobic characteristics. It is thus understood that the glazing according to the invention allows, thanks to the emitter, its hydrophobization as well as the renewal of this hydrophobization over time. Indeed, the emitter associated with the air flows on the surface of the transparent substrate continually ensures the regeneration of the surface in hydrophobic compounds and therefore an improved hydrophobic performance of the substrate.

Claims

DEMANDS 1. Glazing (1) comprising a transparent substrate (S), characterized in that it comprises, in the periphery of the substrate, at least one emitter (2) of hydrophobic compounds by gaseous means; said at least one emitter being arranged to permit a release of said hydrophobic compounds, and a fraction of said released hydrophobic compounds being capable of being deposited on the surface of said transparent substrate.

2. Glazing according to claim 1, characterized in that said transparent substrate (S) comprises: - a fold in a material chosen from the list including glass, glass-ceramic, polymer, or - a laminated assembly of at least two plies (S1, S2), said plies being of the same or different material, said material being chosen from the list including glass, glass-ceramic, polymer.

3. Glazing according to claim 1 or 2, characterized in that said transparent substrate (S) further comprises on its external face at least one layer capable of adsorbing hydrophobic compounds.

4. Glazing according to claim 3, wherein the layer capable of adsorbing hydrophobic compounds comprises: - at least one oxide or nitride of a lanthanide, or an alloy of at least two lanthanides, the lanthanide being chosen from the list including lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or - at least one oxide or nitride of a metal or an alloy of at least two metals, the metal being chosen from the list including scandium, yttrium, titanium, zirconium, hafnium, or - at least one oxide or nitride of an alloy comprising a lanthanide and a metal chosen from the aforementioned lists.

5. Glazing according to claim 3 or 4, wherein the layer capable of adsorbing hydrophobic compounds has a thickness of between 5 and 1000 nm, preferably between 6 and 200 nm, and more preferably between 7 and 30 nm.

6. Glazing according to any one of the preceding claims, characterized in that said emitter comprises at least one reservoir (20) in the form of a solid serving as an emitting surface, said reservoir (20) comprising: - at least one pure hydrophobic compound or several hydrophobic compounds in a mixture, or - at least one hydrophobic compound solubilized and / or dispersed in a polymer matrix, or - at least one hydrophobic compound integrated into a porous matrix.

7. Glazing according to any one of claims 1 to 5, characterized in that said emitter comprises a reservoir (20') and an emitting surface (21), said reservoir being a volume communicating with said emitting surface.

8. Glazing according to claim 7, characterized in that the volume of said reservoir (20') comprises at least one hydrophobic compound found: - in solid form, or - in liquid form, or - solubilized and / or dispersed in a polymeric matrix, or - integrated into a porous matrix.

9. Glazing according to any one of claims 7 or 8, characterized in that the emitting surface (21) comprises: - at least one membrane (210), and / or - at least one plate with at least one opening (212).

10. Glazing according to any one of claims 7 to 9, characterized in that the emitter (2) comprises a protective layer for the emitting surface (21), said protective layer being made of a porous material.

11. Glazing according to claim any one of claims 8 to 10, characterized in that when the reservoir (20') comprises at least one compound hydrophobic in liquid form, the emitter (2) further comprises at least one channel (22) connecting the emitting surface (21) to the reservoir (20').

12. Glazing according to claim 11, characterized in that the emitter (2) further comprises a diffusion means.

13. Glazing according to any one of the preceding claims, characterized in that it further comprises at least one means for heating the emitter.

14. Glazing according to any one of the preceding claims, characterized in that it further comprises a frame (3) in which the transparent substrate (S) is mounted.

15. Glazing according to claim 14, characterized in that said frame (3) is arranged to also carry the emitter (2).

16. Glazing according to any one of the preceding claims, characterized in that the hydrophobic compounds of the emitter (2) have a vapor pressure between 10' 8 Pa and 1 Pa, at a temperature between 20°C and 30°C.

17. Glazing according to any one of the preceding claims, characterized in that the hydrophobic compounds of the emitter (2) are selected from: (a) a carboxylic acid of formula (I): R-COOH in which R represents a linear, branched or cyclic, saturated or unsaturated alkyl group, in C4-C22, preferably R is an alkyl group of formula (A): CnH2n+i, in which n is between 6 and 20, or (b) a phosphate of formula (II): RO-PO(OH)2 in which R represents a linear, branched or cyclic, saturated or unsaturated alkyl group, in C4-C22, preferably R is an alkyl group of formula (A): CnH2n+i, in which n is between 6 and 20, or (c) a phosphonic acid of formula (III): R-PO(OR')(OR”) in which R, R' and R” represent a hydrogen atom, an alkyl group or an aryl group, in C4-C22, preferably R, R' and R” are alkyl groups of formula (A): CnH2n+i, in which n is between 6 and 20, or (d) a silicone, (e) a paraffin, or (f) a mixture of these.

18. Use of glazing (1) according to any one of the preceding claims as rainproof glazing.

19. Use of rainproof glazing according to claim 18, as glazing for buildings, land vehicles, aircraft or watercraft, or street furniture, preferably as cockpit glazing for aircraft.

20. A method for hydrophobicizing glazing (1) according to any one of claims 1 to 17 comprising the following steps: - gaseous release of hydrophobic compounds from the emitter (2) at a pressure ranging from 2.10 4 Pa at 10 5 Pa, - deposition on the transparent substrate of a fraction of said hydrophobic compounds released by means of a flow or stream of air flowing parallel to said transparent substrate and at a speed of at least 70 meters per second.

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