Monolithic roof glazing for a motor vehicle

Abstract

Monolithic glazing comprising a sheet (1) of clear glass, said glazing comprising the following elements in succession, from the outside (5) to the inside (4) of said glazing: - the single sheet (1) of clear glass, - a stack of layers (2) reflecting infrared radiation, - a polymer layer (3), said polymer layer comprising a coloring agent, said coloring agent absorbing light in the visible range and being substantially transparent to infrared radiation.

Description

[0001]DESCRIPTION Title: Monolithic roof glazing for automobiles 5 The invention relates to glazing for automobiles and in particular for use as automobile roof glass. Glass glazing used as a panoramic opening or fixed roof in vehicles must meet a certain number of criteria, with regard to the heating of the interior of the vehicle under strong insolation: - on the one hand, not to let through all of the incident solar radiation so as not to excessively heat the interior space of the vehicle and / or limit energy consumption (due for example to excessive use of air conditioning due to the quantity of heat entering the passenger compartment), and - on the other hand, to let through a sufficiently large quantity of light to sufficiently illuminate the interior space and ensure a minimum of exterior visibility to maintain visual comfort and a feeling of comfort.Meeting these two requirements, namely preventing excessive entry of energy radiation and sufficiently illuminating the interior space, is necessarily the result of a compromise. There is therefore a demand for windows with the best compromise in terms of reflecting thermal energy while maintaining a certain transparency to light. 30 Furthermore, CO2 reduction is today a major issue for the industry. For example, in the context of CO2 energy savings, the United States Code of Federal Regulation (CFR, https: / / www.law.cornell.edu / cfr / text / 40 / 86.1869-12) grants CO2 credits to automobile manufacturers in the NAFTA market for off-cycle CO2 reduction technologies, particularly involving IR-reflective coatings or heat-absorbing glass.Thus, a panoramic roof glazing has an outer surface that is highly exposed to direct sunlight, which causes heat and glare if the glass does not include such coatings or is not tinted in its mass. The initial technical objective of the present invention is to limit glare by reducing the transmission of light through the glass, and also to improve the anti-solar performance in automotive glazing and in particular those used as roofs, so as to avoid heating of the interior space of the passenger compartment. To evaluate the transmission of heat through a glazing, the total solar transmittance (TTS) is often measured according to ISO 13837 with the convention "A" AM 1.5. The anti-solar performance is therefore measured by the total transmitted solar energy (TTS) for this type of glazing.To assess the light transmission through glazing in the visible range (380-780 nm), the light transmission TL as measured according to ISO9050 (2003) can be used, for example. The TL can be reduced by absorption. According to current techniques, absorption is achieved by using a mass-tinted glass sheet in the glazing or alternatively or in addition to one or more tinted PVB layers, within a laminated glazing, i.e. made up of several assembled glass sheets. However, such constructions lead to heating of the glazing. Another important factor concerning anti-solar glazing and its ability to prevent heating of the interior passenger compartment is its ability to selectively reflect solar infrared rays.Usually, such a capacity is obtained by stacking thin layers (i.e., layers with a thickness of the order of a few nanometers or a few tens of nanometers), one of which has a high reflection coefficient in the thermal infrared. This capacity is generally obtained by a stack comprising at least one and preferably two or even three silver layers with a thickness of a few nanometers, in particular of the type described in applications WO2005 / 051858 or WO2013 / 104439, to which reference will be made for further details on such stacks. The capacity of a glazing equipped with such stacks to reflect infrared is, for example, measured by the total emissivity at normal incidence ^n, for example as measured according to standard NF EN 12898 (2001). The lower the emissivity ^n, the more the glazing reflects infrared rays.To satisfy the objectives described above, several configurations of laminated structures have already been described. 25 According to a first possibility, we know, from publication WO 2006 / 108980A2, the use of tinted glasses which absorb part of the radiation and which block by filtering a major portion of the spectrum of the incident radiation, without distinction between the different parts of the solar spectrum (UV-Visible–near IR). According to other possible configurations, it has been proposed to use a tinted interlayer binding the two glass sheets also optionally tinted, in particular a tinted PVB (polyvinyl butyral) sheet. For example, we can also refer to publication EP0687554A1 for an example of such a configuration.The specification of patent US6910729 alternatively describes a glazing with a thermal comfort effect combining an electrochromic glass 5 with a low-emissivity layer arranged on the surface facing the interior space of the vehicle. Patent application EP 1060876 A2 describes, according to another solution, a laminated glazing consisting of an outer glass sheet, a solar protection stack 10 comprising two silver layers arranged on face 2 (the faces being numbered from the outside to the inside), a clear PVB sheet, a tinted PVB sheet, and an inner glass sheet, on which is deposited a low-emissivity layer of fluorine-doped tin oxide. 15 Also, various and other combinations of the preceding systems (tinted PVB and / or glass) have been proposed. In this way, in the end, values ​​of light transmission T are generally obtained. Lof the order of 8 to 20% for a TTS factor of the order of 20 to 35%. 20 While such values ​​are generally satisfactory, the solutions proposed to date are, however, expensive and complex to implement and the price of the final glazing is relatively high, due in particular to the high price of a mass-tinted glass and / or a mass-tinted PVB (or another interlayer). By mass-tinted, it is meant that the colorant is introduced during a manufacturing step of the product (glass or PVB) so as to be distributed homogeneously throughout the volume of said product, as opposed to a clear glass or a clear PVB which does not contain such colorants. However, the current solutions as described above appear relatively expensive and complex to implement, which lead to a joint reduction, without any possible adjustment, of the TTS and the TL,using in particular tinted glass and / or a tinted PVB sheet in a laminated glazing, cannot however be obtained without a joint increase in the emissivity of the glazing. In addition, all the configurations described above relate to laminated glazing, i.e. comprising at least two glass panels. Such glazing is expensive and quite complex to obtain, even if current techniques are mastered. Also, it increases the overall weight of the vehicle (thermal or electric) and therefore its consumption. 10 In order to obtain the best TL / TTS / emissivity compromise, a glazing is sought, which has an absorption profile that is just as effective but whose manufacture is much less complex than those of the prior art, and in particular based on a single (or monolithic) glazing,that is to say 15 comprising only a single glass substrate (glass sheet). The provision of such single glazing is the subject of the present invention. In particular, according to the present invention, glazings are preferably sought which jointly have the following specifications: - a TTS of the order of 20% or less, - a light transmission TL of less than 10% or even less than 5% and ideally of the order of 1 to 2%, - an emissivity^n as low as possible and in particular less than or equal to 30%. The problem underlying the invention is therefore to propose a glass that is easy and economical to manufacture, in particular one that does not include tinted glass or tinted PVB in its mass, which can in particular be used as a roof for an automobile, 30 which makes it possible to meet the desired compromise between TTS and TL, in particular a light transmission in the visible TL of less than 10%, or even less than 5% and a TTS factor of less than 20%,and low emissivity, in particular less than or equal to 30%. More particularly, the preceding technical problem is solved thanks to the monolithic glazing according to the invention. By monolithic glazing, is conventionally understood in the field of construction a glazing which comprises only a single 5 sheet of glass (see for example “The professional dictionary of construction” Eyrolles editions). Such glazing has the following characteristics: it comprises as a support and protective element a single sheet of clear glass. It comprises the succession of the following 10 elements, from the outside to the inside of said glazing: - said sheet of clear glass, - a stack of layers reflecting infrared radiation, in particular from 780 nm and preferably up to the far infrared (from 3 to 50 micrometers), said stack being preferably in contact with the inner surface of said sheet of clear glass, - a layer of a polymeric compound,preferably deposited directly on said stack of layers or bonded to it via a layer of an adhesion promoter, said polymeric compound comprising a coloring agent, said coloring agent absorbing light located in the visible range, between 380 and 780 nm, and being substantially transparent to infrared radiation, in particular to infrared radiation, in particular of wavelength between 780 and 2000 nm, said layer being in contact with the external environment (i.e. it is the last element of said succession, without a glass sheet,layer or stack covering it). The terms "exterior" and "interior" refer to the positioning of the glazing in the vehicle it equips. The external face of the glass sheet is at least partially bare according to the invention (i.e. directly in contact with the air outside the vehicle). Additional and advantageous characteristics of such glazing are given below which can of course be combined with each other if necessary: ​​- Said colorant has on an absorption spectrum between 380 and 2000 nm, as measured by a Perkin–Elmer lambda 950 spectrophotometer at 25°C, for a layer of 40 10 micrometers in an acrylate polymer and at a concentration of 1% by mass, an average absorbance between 780 and 2000 nm at least 3 times lower than the average absorbance between 380 and 780 nm and preferably at least 5 times lower,or at least 7 times lower. 15 - Said dye is black or substantially black. - Said dye has at 25°C, an average molar extinction coefficient (or molar absorptivity) between 780 nm and 2000 nm at least 3 times lower than the average molar extinction coefficient between 380 nm and 780 nm and preferably at least 5 times lower. As is well known, the molar extinction coefficient, also called molar absorptivity or molar absorption coefficient, characterizes the capacity of a composition to absorb light. The Beer-Lambert law 25 stipulates that it does not depend on the concentration of the composition or the thickness crossed by the light but on the nature of the solute (here the dye) and the solvent (here the matrix), the wavelength of the incident light and the temperature. An “average” molar extinction coefficient 30 thus corresponds, within the meaning of the present invention, to the average of said coefficients,as measured over the wavelength interval considered. - The stack of layers reflecting infrared radiation is a stack comprising at least two silver-based functional layers, preferably at least 3 silver-based functional layers, separated by layers of dielectric materials, in particular by oxides or nitrides. 5 - The polymer layer comprises or preferably consists of a polymeric compound chosen from (meth)acrylate compounds, preferably polyfunctional and comprising at least two acrylate functions. - The polymer layer is obtained by crosslinking a polymerizable composition comprising (meth)acrylate compounds, optionally comprising a polyorganosiloxane group, a polymerization initiator, and optionally an adhesion promoter,wherein said (meth)acrylate compounds comprise high functionality (meth)acrylate compounds: - having at least 4 (meth)acrylate functions and representing, by mass relative to the total mass of said composition, in increasing order of preference, at least 65%, at least 70%, at least 80%, at least 90%, at least 94% or - having at least 5 (meth)acrylate functions and representing, by mass relative to the total mass of said composition, in increasing order of preference, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 94% of said composition. 25 - Preferably, the polymerizable composition comprises high functionality (meth)acrylate compounds having at least 6 (meth)acrylate functions and representing, in order of increasing preference, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 94% of said composition. By (meth)acrylate is meant,an acrylate or a methacrylate. (Meth)acrylate functions are understood to mean an acrylate function (CH2=CH-COO-) or a methacrylate function (CH2=CH(CH3)-COO-). The polymeric layer is essentially organic in nature. It is obtained from a polymerizable composition. It results from the crosslinking of the polymerizable organic compounds present in the polymerizable composition. The (meth)acrylate compounds represent by mass relative to the total mass of the polymeric layer, in ascending order of preference: - at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, and / or - at most 99%, at most 98%, at most 97%, at most 96%,at most 95%. The (meth)acrylate compounds have a molecular mass or average molecular mass (hereinafter molecular mass) of between 150 and 10,000 g / mol. The (meth)acrylate compounds comprise high-functionality (meth)acrylate compounds. These high-functionality compounds are chosen from acrylic or methacrylic acid esters comprising, in order of increasing preference, at least 4, at least 5, at least 6 (meth)acrylate functions. The (meth)acrylate compounds comprising high-functionality (meth)acrylate compounds have a molecular mass, in order of increasing preference, of between 500 and 10,000, between 800 and 5,000, between 1,000 and 2,000 g / mol. According to an advantageous embodiment, the high-functionality (meth)acrylate compounds comprise at least 4 (meth)acrylate functions. They represent, in mass per 30 relative to the total mass of the polymeric layer,in ascending order of preference, at least 65%, at least 60%, at least 70%, at least 80%, at least 90%, at least 94%. According to another advantageous embodiment, the high-functionality (meth)acrylate compounds having at least 5 (meth)acrylate functions represent, by mass relative to the total mass of the polymeric layer, in ascending order of preference, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 94% 5 According to another advantageous embodiment, the high-functionality (meth)acrylate compounds having at least 6 (meth)acrylate functions represent, by mass relative to the total mass of the polymeric layer, in ascending order of preference, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 94%. Advantageously,the (meth)acrylate compounds a) comprise high-functionality (meth)acrylate compounds comprising at least 6 (meth)acrylate functions and a molecular mass ranging from 1000 to 2000 g / mol. By way of example, mention may be made of the product CN9010EU marketed by the company Sartomer which is an aliphatic urethane-acrylate prepolymer comprising 6 (meth)acrylate functions and a molecular mass of 1450 g / mol. According to advantageous embodiments of the invention, said polymerizable composition also has the following characteristics: - it comprises at least one polymerization initiator (or primer), preferably a photoinitiator, - the polymerization initiator represents 0.1 to 20%, or 1 to 15%, preferably 3 to 10% and better still 4 to 8% by mass of said composition, - the (meth)acrylate compounds a) are chosen from monomers, oligomers, prepolymers or polymers comprising at least one (meth)acrylate function,30 - the (meth)acrylate compounds are chosen from acrylic or methacrylic acid esters comprising at least two (meth)acrylate functions, - the (meth)acrylate compounds optionally comprise at least one aliphatic urethane-acrylic oligomer, - the (meth)acrylate compounds comprise at least one oligomeric or prepolymeric monomer comprising, in increasing order of preference, at least 2, at least 3, at least 4, at least 5, at least 6 (meth)acrylate functions, 5 - the polymerizable composition may further comprise at least one additive chosen from adhesion promoters, plasticizers, absorbers, separating agents, heat and / or light stabilizers, thickening agents or surface modifiers, 10 - the sum of all the additives is between 0 and 10%, preferably 0 and 5%, or even 0.5 to 2.5% by mass relative to said composition. According to an advantageous embodiment,the polymerizable composition comprises at least one additional compound 15 comprising a polyorganosiloxane group and at least two (meth)acrylate functions. According to the invention, the polymerization initiators and the compound comprising a polyorganosiloxane group are not considered to be additives. 20 The additional compound comprising a polyorganosiloxane group has, for example, a molecular mass of between 500 and 10,000 g / mol. Advantageously, said additional compound has a molecular mass, in order of increasing preference, of between 500 and 15,000, of between 1,000 and 10,000, of between 3,000 and 7,000 g / mol. The molecular masses can be determined by gel permeation chromatography. Said additional compound represents 0.05 to 5% by weight of the polymerizable composition. The compound comprising a polyorganosiloxane group represents, in order of increasing preference, 0.05 to 5%, 0.1 to 4%, 0.2 to 3%, 0.3 to 2%, 0,3 to 1.5% of the total mass of the organic protective layer. The polyorganosiloxane group of the compound comprising a polyorganosiloxane group consists of 2 to 1000 organosiloxane units. This polyorganosiloxane group may be part of the main chain of the compound or part of a side chain. The compound comprising a polyorganosiloxane group may be chosen from modified polyorganosiloxanes comprising a plurality of (meth)acrylate functions. This type of compound corresponds to a compound having at least two (meth)acrylate functions introduced in any position of a polyorganosiloxane chain (or skeleton), in particular on a side chain or at the end of the main chain. In this case, the compound comprising a polyorganosiloxane group represents, in order of increasing preference, 0.05 to 1.5%, 0.1 to 1%, 0.2 to 0.7%, 0.4 to 0.6% by mass of said composition. This type of compound is for example marketed under the name Byk 3505. The compound comprising a polyorganosiloxane group may be chosen from modified poly(meth)acrylates comprising 20 polyorganosiloxane groups and at least two (meth)acrylate functions. This type of compound is for example marketed by the company Sartomer under the name CN9800 (“difunctional aliphatic silicone acrylate oligomer”). In this case, the compound comprising a polyorganosiloxane group represents, in increasing order of preference, 0.2 to 4%, 0.4 to 3%, 0.6 to 2%, 0.9 to 1.6% by mass of said composition. - The thickness of the polymeric layer is between 0.1 and 25 micrometers, preferably between 0.1 and 20 micrometers, more preferably between 0.2 and 10 micrometers, or even between 0.2 and 5 micrometers and very preferably between 0.5 and 3 micrometers. - The coloring agent is chosen from the compounds of the Epolight 7527® range,in particular compounds 7527B and Epolight 7527C marketed by the company Epolin. - The coloring agent is chosen from Sudan Black B® ((2,2- 5 dimethyl-1,3-dihydroperimidin-6-yl)-(4-phenylazo-1- naphthyl)diazene, C29H24N6, CAS 4197-25-5) or Nigrosine Solvent black 5 (CAS 11099-03-9), and is preferably Sudan Black B®. - The coloring agent represents between 5 and 70% by weight of the polymer, preferably between 10 and 60% by weight and more preferably between 20 and 50% by weight of the polymer. - The glass sheet has a thickness of between 0.7 mm and 5 mm and preferably between 1.6 mm and 3.1 mm. - The stack of layers is a system of thin layers 15 with thicknesses between 0.5 and 100 nm which comprises one or more silver-based layers, preferably which comprises at least two silver-based layers. The invention also relates to a use of a monolithic glazing as previously described as a roof, 20 side window,or rear window of motor vehicles. Also, the invention relates to a method for manufacturing a monolithic glazing as described above, comprising a single sheet of glass, characterized in that it comprises the following steps: 25 - depositing a stack of layers reflecting infrared radiation, in particular with a wavelength greater than 780 nm, on an internal face of said sheet of glass, - depositing on said stack a polymeric layer 30 comprising a coloring agent as described above, said coloring agent absorbing substantially the light located in the visible range and being transparent to infrared, - drying and / or hardening the polymeric layer comprising the coloring agent, in particular by UV treatment. By way of non-limiting example and for a better understanding of the present invention,Figure 1 attached in the appendix shows an embodiment of a glazing according to the invention seen in a cross-section. This embodiment is particularly suitable for producing a glazed roof structure for an automobile 10 but could also be used as a rear window, or even as side glazing. The glazing 10 according to the invention comprises a sheet of clear glass 1, i.e. not tinted in its mass. In particular, such glazing is conventionally obtained by a process known as float glass. Such untinted glasses may in particular have a light transmission TL of at least 88%, and most often of the order of 90%. The glazing according to the invention comprises only a single sheet of glass. The glazing 10 separates the interior space 4 from the exterior 5 of the vehicle and can be curved as shown in Figure 1. The glass sheet has a thickness preferably between 1 mm and 8 mm,in particular between 1 and 4 mm. For reasons of weight saving, the single glass sheet must make it possible to achieve as good a compromise as possible between low thickness and high safety, in particular when the glazing is mounted in an automobile. 30 Such a compromise can be obtained in particular with a tempered glass sheet whose thickness is between 1.5 mm and 3.1 mm, for example 2.1 mm. According to the invention, the external face of the glass sheet 1 is preferably bare, while on the internal part of the sheet 1 is deposited a stack 2 of layers selectively reflecting infrared. Such stacks are well known and in particular comprise a combination of layers based on precious metals, in particular, based on silver and dielectric materials often called interference layers. In a known manner,these stacks consist of a succession of layers of dielectric materials such as oxides and / or nitrides and metal layers including silver-based layers whose so-called "low emissive" properties make it possible to selectively reflect so-called solar or near infrared (in particular with a wavelength between 780 nm and 2000 nm) and to allow at least part and preferably more than 70%, or even more than 80% of the visible light of the solar spectrum (with a wavelength between 380 and 780 nm) to pass through, in particular by minimizing light reflection by means of said interference layers or combination(s) of interference layers. In addition, the presence of such a stack on the internal face of the inner sheet makes it possible to maintain heat in the passenger compartment in winter. The stacks according to the invention are in particular selected in such a way that their resistance per square is less than 1.5 Ohms per square,more preferably less than 1.2 Ohms per square, or even less than 1.1 Ohms per square. The resistance per square can for example be measured using a Nagy Mess-systems SRM-14T type device. Such stacks can comprise up to several tens of layers whose thickness is of the order of 1 to 30 nm and are currently deposited by so-called cathode sputtering techniques, often magnetron-assisted. The preferred stacks according to the invention comprise two, and preferably three or even four silver-based layers. Examples of such stacks are described in particular in the publications WO2005 / 051858A1, WO2013 / 104439 or WO2013 / 107983 cited above. According to the invention, the low-emissivity stack is covered with a layer 3 comprising a coloring agent. This additional layer 3 is constituted by a layer 10 of a polymer compound. Preferably,such a polymer may be or comprise a polymer of the (metha)crylate type, in particular of the type described in publications WO2018 / 178559, WO2018 / 178547 or WO2018 / 115768, WO2020 / 016527 or more preferably as described in application WO2020 / 016529 as described previously. According to the invention, the polymeric layer 3 may advantageously be obtained from a liquid composition comprising (meth)acrylate oligomers comprising at least one methacrylate function and preferably a plurality of methacrylate functions. For example, the liquid composition may advantageously comprise at least one aliphatic urethane-acrylic oligomer, at least one polymerization initiator and the coloring agent. According to the invention, the polymeric layer 3 can advantageously be obtained from a liquid composition comprising (meth)acrylate compounds chosen from monomers, oligomers,or polymers comprising at least one methacrylate function and preferably several methacrylate functions. For example, the liquid composition comprises at least one monomer or oligomer of said (meth)acrylate compounds, preferably polyfunctional, at least one polymerization initiator and the coloring agent. Advantageously, the coloring agent is present in the initial composition in an amount of between 5% and 70% relative to the total mass of the polymeric compounds present in the layer of polymeric compound, preferably between 10 and 60%, or even between 20 and 50% by weight relative to said total mass. The polymeric layer 3 may further comprise an adhesion promoter on the stack of layers 2. The deposition of the polymeric layer 3 on the stack of layers 2 may be carried out by application at room temperature of the liquid composition described above, by roller coating, by spraying, by dipping,by curtain coating or by spraying, or by spin coating techniques (centrifugal coating). The polymeric layer 3 is advantageously then hardened by drying at a temperature below 200°C, by UV crosslinking, or by electron beam. The thickness of the dried and / or hardened polymeric layer 3 may be between 0.1 and 25 micrometers, typically between 0.5 and 3 micrometers. According to one possible embodiment, the polymeric layer comprises an adhesion promoter with the stack. According to an alternative embodiment, the surface of the stack of layers on which the colored polymeric layer is deposited may be previously treated with an adhesion promoter agent. According to the invention, the polymer layer serves as a matrix for a dye (or coloring agent) specifically chosen for its light absorption qualities located in the visible range (380-780 nm) but also substantially transparent to infrared,in particular those between 780 and 2000 nm. By absorbing visible light, it is meant that said dye absorbs the majority of the visible light between 380 and 780 nm, for example at least 60% or even more than 70% or more than 75%, or even substantially all of the visible light between 380 and 780 nm. Similarly, by transparent to infrared, it is meant that said dye lets through the majority, for example at least 60%, preferably at least 70% or even more than 80% or even more than 90% or even substantially all of the infrared, in particular between 780 and 2000 nm. According to an advantageous embodiment, such coloring agents are the compounds of the Epolight 7527® range,in particular the compounds 7527B and Epolight 7527C marketed by the company Epolin. (https: / / www.epolin.com / epolight-voirt-dyes-for-solvent-based-systems / ). Figure 2 attached shows the absorption spectrum of the compound Epolight 7527C in an acrylate layer and at a concentration of 1% by mass, as an example. The absorbance measured between 380 and 780 nm is 0.79 and the absorbance measured between 780 and 2000 nm is 0.08. Alternatively, dyes of the Sudan type and in particular the dye Sudan Black B can be chosen, the structural formula of which is given below:, 25 Of course, the present invention is not limited to such compounds and any dye having, in its matrix, a low infrared absorption coefficient between 780 nm and 2000 nm, and a high absorption coefficient in the visible range can be used according to the invention. The dye used is therefore in principle black but it is also possible to use dyes which do not absorb all of the visible light but at least 70% or even at least 80% or even of it, and which then has a slight coloration, although dark.More particularly, such a method for manufacturing a glazing unit comprises the following steps: - deposition by vacuum cathode sputtering techniques of an infrared-reflecting stack 2 as described above, on the inner face of a glass sheet 1, 10 - optionally shaping of said glazing unit such as bending or toughening, - deposition by liquid means, in particular by roller coating, by spraying, by dipping, by curtain coating or preferably by spray-coating on the inner face of said glass sheet (sheet 1 provided with the stack 2) of a polymeric layer 3 comprising the coloring agent or a varnish comprising the coloring agent, - drying and optionally hardening of the polymeric layer 3, in particular by drying and / or hardening by UV.Used as monolithic glazing, particularly for an application as a glass roof for automobiles, the glazing according to the invention makes it possible to solve the technical problem previously described thanks to its particular structure. In particular, it allows the following advantages to be combined: - a low cost of the materials used in its composition since it does not contain the most expensive elements present in current structures (in particular no PVB initially colored in its mass, no colored glass 30 in its mass) and therefore a low manufacturing cost.Furthermore, the liquid deposits that can be used according to the invention are generally inexpensive due to a high line speed and the colorants used are commercial and inexpensive; - the possibility of adjusting the light transmission of the glazing by adjusting the mass concentration of colorant in the polymeric layer up to values ​​of up to 70% of the total weight of said layer (dry matter).5 - optimal solar control properties of the glazing obtained: a) thanks to the presence on the glass sheet of a stack which reflects the solar infrared but allows a major part of the radiation in the visible range to pass through, b) due to the nature and positioning of the coloring agent within the glazing: the major part of the infrared portion of the solar spectrum is reflected by the stack of layers then the residual radiation, comprising essentially the visible portion of said radiation, is partially absorbed by the layer comprising the coloring agent, depending on the concentration in said layer. The glazing according to the invention thus has a low TTS value. Since the infrared does not reach the polymeric layer, no additional heating of the glazing and consequently of the passenger compartment of the vehicle is observed.In addition, the light reflection in the visible range is often low, typically less than 10%, on the internal side of the glazing, which ensures improved interior comfort, particularly at night, by avoiding a mirror effect on said internal face of the glazing. The stack of layers and the concentration of the colorant are advantageously chosen in combination to allow a sufficiently large quantity of light to pass through to sufficiently illuminate the interior space and thus maintain visual comfort and a feeling of comfort. Thus, it is advantageous to choose a stack of layers which, when deposited on a clear glass with a thickness of 2.1 mm without any other element, leads to a glazing having a light transmission T. Lin the sense previously described of at least 50%, or even at least 60% or even at least 70%. Two examples of the production of a glazing 5 according to the invention are given below: A- Manufacture of a monolithic structure according to the invention: A sample A is prepared, of a structure as described previously in relation to FIG. 1, with dimensions 10 × 10 cm². Sample A is obtained in the following manner: - A stack of 15 layers is deposited on a first clear glass with a thickness of 2.1 mm marketed by the applicant company under the reference Planiclear® (TL of approximately 90%, uncolored) by magnetron-assisted cathode sputtering techniques. The stack comprises three layers of silver and is described in example 14 of publication WO2005051858. Its resistance per square is 1.0 Ohm / square, as measured using a device type SRM-14T from 20 Nagy Mess Systems).On the stack of thin layers, a liquid composition of the following composition is deposited: - a hexa-functional aliphatic acrylate oligomer (hereinafter 6-functional acrylate oligomer) having a molecular mass of 1450 g / mol, marketed by the company Sartomer under the reference CN9010EU. - a modified polyorganosiloxane comprising a plurality of (meth)acrylates having a molecular mass of 6500 g / mol, marketed by the company Byk under the name Byk 30 3505. - an adhesion promoter consisting of a triacrylate monomer of the acid type marketed by the company Sartomer under the name SR9051. - a photoinitiator marketed by the company Lambson under the name Speedcure 500. The following table indicates the different proportions of the 4 initial ingredients of the initial mixture: 5 [Table 1]. The 4 ingredients, precursors of the initial polymer matrix, are dispersed in ethyl methyl ketone (MEK), used as a solvent. Before the solvent removal step, according to the invention, the Epolight 7527C dye described above is additionally added to the initial solution. According to a first example, a mixture is made comprising 12% by weight of the mixture of precursors and 12% by weight of said dye with 76% by weight of MEK. According to a second example, a mixture is made comprising 12% by weight of the mixture of precursors and 5% by weight of said dye with 83% by weight of MEK. The liquid composition thus obtained is filtered with a PTFE filter with a diameter of 0.2 micrometers and is then deposited on the glass substrate coated with the stack by spin coating until a thickness of 5 micrometers is reached. The layer thus obtained is hardened by UV irradiation (UVB dose of approximately 280 mJ / cm 2, running speed of 10 m / min). 25 The thickness of the dry colored layer is approximately 1 micrometer. B- Characterization of the glazing according to the invention: The optical characterizations of the glazing as described above are carried out with a Lambda900 spectrophotometer from Perkin Elmer. The light factors (TL and RL) were measured according to the ISO9050 (2003) standard. The total solar transmission (TTS) was measured according to the ISO 13837 standard with the "A" AM 1.5 convention. The emissivity was calculated according to the criteria defined in the international standard NF EN 12898: 2001. In the context of the examples set out below, it is considered that an emissivity of up to 30% is satisfactory and that beyond this the material can no longer be used satisfactorily as insulating glazing. Table 2 below shows the main colorimetric data of the glazing according to the invention when the Epolight 7527C colorant is used: [Table 2] 20 The light transmission TL is effectively reduced by the colored layer. The glazing obtained visually appears dark blue in transmission, from inside the passenger compartment. The TTS measured according to ISO 13837 convention A, AM1.5 is much lower than 20%, substantially equal to, or even lower than, the values ​​obtained for the prior art configurations previously described and based on the use of PVB and / or colored glass. The emissivity is less than 30% for both examples. According to the invention, it appears possible to easily modulate the light transmission T L , the total energy transmission of the TTS glazing and the emissivity ^n by acting on the concentration of coloring agent. 5

Claims

CLAIMS 1. Monolithic glazing comprising a single sheet of clear glass (1), said glazing comprising the following sequence of elements, from the outside (5) to the inside (4) of said glazing: - said single sheet (1) of clear glass, - a stack of layers (2) reflecting infrared radiation, preferably in contact with the inner surface of said clear glass sheet, - a layer of a polymeric compound (3), said polymeric layer comprising a colorant absorbing light in the visible range between 380 and 7805 nm and being substantially transparent to infrared radiation with wavelengths between 780 and 2000 nm, said polymeric layer being directly in contact with the external environment. 2.Monolithic glazing according to claim 1, in which said colorant exhibits, as measured by a Perkin–Elmer lambda 950 spectrophotometer over an absorption spectrum between 380 and 2000 nm, at a concentration of 1 wt% in a 40 micrometer layer of (meth)acrylate polymer, an absorbance between 780 and 2000 nm at least 3 times lower than the absorbance between 380 and 780 nm.

3. Monolithic glazing according to claim 1 or 2, in which said colorant exhibits, at 25°C, an average molar extinction coefficient between 780 nm and 2000 nm at least 3 times lower than the average molar extinction coefficient between 380 nm and 780 nm.

4. Monolithic glazing according to any one of the preceding claims, wherein the stacking of infrared radiation reflecting layers (2) is a stacking comprising at least two functional layers. silver-based and preferably at least 3 silver-based layers, separated by layers of dielectric materials, in particular oxides or nitrides.

5. Monolithic glazing according to any one of the preceding claims 5, wherein said polymeric layer (3) comprises and preferably is made of a polymeric compound selected from (metha)crylate compounds, preferably polyfunctional and comprising at least two acrylate functions. 6.Monolithic glazing according to any one of the preceding claims, wherein the polymeric layer (3) is obtained by crosslinking a polymerizable composition comprising (meth)acrylate compounds, optionally a polyorganosiloxane group, optionally a polymerization initiator, optionally an adhesion promoter with said stacking, the (meth)acrylate compounds comprising and preferably being high-functionality (meth)acrylate compounds: - having at least 4 (meth)acrylate functions and representing, by mass relative to the total mass of the organic protective layer, at least 65% or - having at least 5 (meth)acrylate functions and representing, by mass relative to the total mass of the organic protective layer, at least 50%.5 7.Monolithic glazing according to any one of the preceding claims, wherein the thickness of the polymer layer (3) is between 0.1 micrometers and 25 micrometers, in particular between 0.2 and 10 micrometers, preferably between 0.5 and 3 micrometers.

8. Monolithic glazing according to any one of the preceding claims, wherein the coloring agent is selected from among the compounds in the Epolight 7527® range, in particular compounds 7527B and Epolight 7527C marketed by Epolin.

9. Monolithic glazing according to any one of claims 1 to 7, wherein the coloring agent is selected from Sudan Black B® (CAS 4197-25-5) or Nigrosine Solvent Black 5 (CAS 11099-03-9), and preferably is Sudan Black B®.

10. Monolithic glazing according to any one of the preceding claims, wherein the coloring agent represents between 5 and 70% by weight of the polymer layer, preferably between 20 and 50% by weight of the polymer layer.

11. Monolithic glazing according to any one of the preceding claims, characterized in that the glass sheet has a thickness of between 0.7 mm and 5 mm, and preferably between 1.6 mm and 3.1 mm.

12. Use of monolithic glazing according to any one of the preceding claims as a roof, side window, or rear window of motor vehicles.

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