WO2019158865A1

WO2019158865A1 - Fire‑resistant glazing

Info

Publication number: WO2019158865A1
Application number: PCT/FR2019/050330
Authority: WO
Inventors: Marine BRUNET; François COMPOINT
Original assignee: Saint-Gobain Glass France
Priority date: 2018-02-16
Filing date: 2019-02-14
Publication date: 2019-08-22

Abstract

The invention relates to fire-resistant glazing comprising a first untempered glass sheet, a second untempered glass sheet and a solid intermediate stack, characterized in that the intermediate stack comprises a first intumescent layer, a substantially inorganic layer and a second intumescent layer.

Description

FIREPROOF GLAZING

The present invention relates to the field of fireproof glazing.

The evaluation criteria for fire-resistant glazing, which may depend on the regulations in force and the final application of the glazing, generally take into account the mechanical stability, the watertightness and the thermal insulation capacity of the glazing. The European standard EN 13501 defines three classes: E (fire stability: mechanical resistance, flameproofness and ability to hold fumes), EW (fire stability with heat radiation limit) or El (stability and fire resistance). fire insulation); associated with the time expressed in minutes (30, 60, 90, 120 and 180 minutes) during which the element considered is able to retain these properties. The present invention relates more particularly fireproof glazing class E / EW30 and higher.

Anti-fire glazing is known comprising a highly viscous aqueous solution based on hydrated alkali silicates sealed between two glass sheets (EP 3023245, WO 2007/118886, WO 2007/053248, EP 2072247, EP 2282889, WO 2008/053248 ). In case of fire, the exposed glass sheet breaks quickly. The silicate layer remaining adherent to the second glass sheet is directly exposed to fire. The water contained in this layer evaporates and forms bubbles causing the expansion of the layer and obtaining a solid and opaque inorganic foam. The mechanical and thermal strength properties of this foam ensure the integrity of the second glass sheet and limit the transmission of radiation. This solution, particularly suitable for glazing class E / EW30 and higher, however, has several disadvantages. Such glazings can not be cut. The use of tempered glass, generally necessary to guarantee a sufficient mechanical strength, and the sealing of the liquid interlayer require on-demand production to the desired finished dimensions. Moreover, during the aging of the glazing, the intermediate layer may tend to corrode the glass, to become fuzzy or, although very viscous, to flow under the effect of gravity, and thus cause optical distortions.

Other fireproof glazings are formed of a solid hydrogel layer between two sheets of glass, obtained by crosslinking a solution of water-soluble monomers (US 2016/2000077, EP 2330174). In case of fire, the evaporation of water and the inorganic additives contained in the hydrogel layer can delay the spread of fire. However, unlike the alkali silicate layer, the hydrogel layer does not expand or form an insulating foam. Moreover, such glazings generally require the use of tempered glass sheets and therefore can not be redécoupés.

The object of the present invention is to obviate the drawbacks mentioned above by providing a fireproof glazing, in particular class E / EW30 or higher, which can be cut and does not induce blur or optical distortion .

Thus, one aspect of the present invention relates to a fire-resistant glazing comprising a first non-tempered glass sheet, a second non-tempered glass sheet and a solid intermediate stack, characterized in that the intermediate stack comprises a first intumescent layer, an essentially inorganic layer and a second intumescent layer. The use of a solid interlayer stacked with sheets of untempered glass allows the production of large glazings that can be cut to the desired dimensions. The presence of intumescent layer and inorganic layer in the interlayer stack provides the glazing according to the invention, in case of fire, both a sufficient mechanical strength and a capacity for reducing heat exchange by radiation.

The glass sheets may have a thickness that varies from 1 to 8 mm, preferably 2 to 6 mm. Advantageously, each glass sheet has the same thickness. The glass may be a silico-soda-lime glass obtained by floating on a tin bath (according to the "float" method), a borosilicate glass or any other type of transparent glass. It can be a clear or colored glass according to the desired aesthetic rendering.

Interlayer stacking includes only solid layers. The layers of the stack preferably have a residual amount of water of less than 10%, or even less than 5%, or even less than 1% by weight. In particular, the intermediate stack does not comprise a liquid layer of hydrated alkali silicates. Furthermore, the intermediate stack preferably does not comprise glass sheets, especially between the essentially inorganic layer and the first and second intumescent layers. In other words, the turn according to the invention preferably comprises only two sheets of glass, that is to say only said first and second glass sheets forming the outer surfaces of the glazing. The intermediate stack according to the invention typically has a thickness of 0.5 mm or even 1.0 mm, or even 2 mm to 12 mm, or even 10 mm, 8 mm, 5.0 mm, or even 4.0 mm . The intermediate stack according to the invention comprises at least one essentially inorganic layer. For the purposes of the present invention, the term "essentially inorganic layer" means an inorganic or hybrid organic-inorganic layer comprising less than 40%, preferably less than 30% by weight of carbon. The essentially inorganic layer is typically based on inorganic polymer, silicates or a sol-gel material based on metal oxides. Examples of inorganic polymers include organopolysiloxane resins, especially based on polydimethylsiloxane. Preferably, the silicate-based layers consist essentially of dried alkali silicates. Sol-gel materials based on metal oxides, especially based on silica and / or titanium oxide, are typically obtained by hydrolysis / condensation of alkoxides or metal salts, in particular silicon and / or titanium, optionally functionalized, for example with amine, isocyanate, phosphate or fluoro groups. Preferably, the essentially inorganic layer is based on inorganic polymer, obtained for example from α,--difunctionalized polydimethylsiloxanes, especially by vinyl groups, crosslinked. The substantially inorganic layer typically has a thickness of 0.3 or even 0.5 mm at 6.0 mm, 5.0 mm, 4.0 mm, 3.0 mm, or even 2.0 mm.

The intermediate stack according to the invention comprises at least two intumescent layers: an intumescent layer on each side of the essentially inorganic layer. According to a particular embodiment, the intermediate stack may also comprise a plurality of intumescent layers, for example two, three or four, on each side of the essentially inorganic layer, the number of intumescent layer preferably being identical on each side. of the essentially inorganic layer. Each intumescent layer typically has a thickness of 0.01 to 1.0 mm, preferably 0.02 to 0.8 mm, more preferably 0.05 to 0.5 μm. In the case of a single intumescent layer on each side of the essentially inorganic layer, they generally have a thickness of 0.1 to 1.0 mm, preferably 0.1 to 0.8 mm. On the contrary, in the case of a plurality of intumescent layers on each side of the essentially inorganic layer, these have a smaller thickness, generally from 0.01 to 0.5 mm, preferably from 0.05 to 0.3 mm.

The intumescent layers have the property of foaming under the effect of temperature, typically at temperatures above 100 ° C, or even above 180 ° C, for example between 200 and 400 ° C, to reach at least three times, preferably at least five times, or at least eight times or even at least 10 times their initial thickness.

The first and second intumescent layers may be in direct contact with the essentially inorganic layer. For the purposes of the present invention, an element A "in direct contact" with an element B means that no other element is disposed between said elements A and B. On the contrary, an element A "in contact" with an element B does not exclude the presence of another element between said elements A and B. Alternatively, a bonding layer, in particular based on silanes, can be arranged between the first and second intumescent layer and the essentially inorganic layer. This bonding layer makes it possible to improve the adhesion of the intumescent layers with the essentially inorganic layer.

In a particular embodiment, the intermediate stack may also comprise a reinforcing layer between the essentially inorganic layer and each of the first and second intumescent layers. The reinforcing layers improve the fire resistance of the intumescent layer. The intermediate stack thus preferably comprises a first intumescent layer (or a plurality of intumescent layers), a first reinforcing layer, an essentially inorganic layer, a second reinforcing layer, and a second intumescent layer (or a plurality of intumescent layers). ). The reinforcing layers are typically layers based on silicates or a sol-gel material based on oxides metal, especially silica and / or titanium oxide. They typically have a thickness of 0.1 μm, or even 0.5 μm, 1 μm, or even 2 μm at 100 μm, or even 50 μm, 20 μm, or even 10 μm. In this embodiment, the essentially inorganic layer is preferably based on an inorganic polymer, in particular based on organopolysiloxane resins such as polydimethylsiloxane-based resins.

In case of pluralities of intumescent layers on each side of the essentially inorganic layer, each intumescent layer on one side of the essentially inorganic layer is separated from the neighboring intumescent layer by a secondary substantially inorganic layer. The essentially or different secondary inorganic layers may be as defined above for the substantially inorganic layer. They are preferably based on silicates or a sol-gel material based on metal oxides, especially silica and / or titanium oxide. The essentially inorganic secondary layers may be in direct contact with the intumescent layers that are juxtaposed with it. Alternatively, a bonding layer, in particular based on silanes, can be placed between the intumescent layers and the essentially inorganic secondary layers in order to improve their adhesion. The essentially inorganic secondary layers typically have a thickness of 0.1 to 20 μm, preferably 1 to 10 μm.

Each intumescent layer typically comprises a binder and an intumescent agent. The binder can be organic, inorganic or hybrid.

When the binder is an organic binder, it may be a thermoplastic binder, a thermosetting binder or a mixture thereof. Examples of organic binders include homopolymers or copolymers derived from monomers or comonomers selected from vinyl monomers, diene monomers, isocyanate monomers, epoxide monomers, dicarboxylic acid monomers, polyol monomers, polyamine monomers, and mixtures thereof. The vinyl monomers include, but are not limited to, ethylene, propylene, isobutene, isoprene, vinyl chloride, vinylidene chloride, styrene, vinyltoluene, acrylonitrile, vinyl esters, and acrylic monomers. Examples of vinyl esters include vinyl acrylates and vinyl Cl-Cl 2 carboxylates such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl valerate, vinyl hexanoate, vinyl

Vinyl 2-methylhexanoate, vinyl 2-ethylhexanoate, vinyl isooctanoate, vinyl nonanoate, vinyl decanoate, vinyl laurate, vinyl palmitate, vinyl stearate, neodecanoate vinyl and vinyl versatates from 9 to

11 carbon atoms (also called VeoVa for vinyl ester of versatic acid). By acrylic monomers (or acrylates) is meant especially alkyl (alk) acrylates or (alk) acrylic acids such as methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylate, t-butyl, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, dodecyl methacrylate, dodecyl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, and hydroxy-functional acrylate compounds such as 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-hydroxyethyl acrylate and hydroxypropyl acrylate. The diene monomers include, in particular, 1,3-butadiene.

Isocyanate monomers include hexamethylene diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexylisocyanate), toluene 2,4-diisocyanate, 2,4'-dibenzyl diisocyanate, 2,4'-diisocyanate diphenylmethylene diisocyanate, m-xylylene diisocyanate, toluene 2,6-diisocyanate, 4,4'- dibenzyl diisocyanate, 4,4'-diisocyanate diphenylmethylene and 2,2'-diisocyanate diphenylmethylene. The epoxide monomers comprise in particular epichlorohydrin, epibromohydrin, isopropyl glycidyl ether, butyl glycidyl ether, allyl glycidyl ether, 1,4-butanediol diglycidyl ether (1,4-bis (2,3-epoxypropoxy) butane), ethylhexyl glycidyl ether, methyl glycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycidol and glycidyl methacrylate. The dicarboxylic acid monomers include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, sebacic acid, and the like. , phthalic acid, isophthalic acid, terephthalic acid, maleic acid and fumaric acid. The polyol monomers comprise, in particular, ethylene glycol, propylene glycol, butane-1,4-diol, glycerol, trimethylolpropane, polyterythritol and sorbitol. Polyamine monomers include ethylene diamine, propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexamethylenediamine, 1,2-diaminopropane, diphenylethylenediamine, and the like. and 1, 2-diaminocyclohexane. Preferred organic binders include polyethylenes, polyvinyl acrylate, polyvinyl chloride, polyvinyl acetate, polystyrenes, vinyl acetate / ethylene copolymers, ethylene / vinyl ester copolymers , vinyl acrylate / vinyl acetate copolymers, vinyl acetate / ethylene / vinyl ester copolymers, styrene / acrylate copolymers, vinyl toluene / acrylate copolymers, sytene / butadiene copolymers, vinyltoluene / butadiene copolymers, styrene copolymers acrylonitrile, vinyltoluene / acrylonitrile copolymers, polyester-polyurethane copolymers. Particularly preferred organic binders include copolymers based on ethylene and one or more vinyl esters, such as ethylene / vinyl acetate copolymers and ethylene / acetate terpolymers. vinyl / vinyl ester including C9-C1 vinyl loveratate. In some embodiments, the binder may also include phosphorous functions to improve its fire resistance.

The binder is preferably transparent. Transparent binder means a binder having a total light transmittance of greater than 85% and a blur of less than 15% as measured by Hazemeter in accordance with ASTM D 1003-00 with Illuminant C, when applied, then dried and or cross-linked on a glass substrate in a layer of about 300 μm.

By intumescent agent is meant a compound or a mixture of compounds that reacts and / or decomposes under the effect of temperature by releasing essentially incombustible gases. In other words, the intumescent agent is a compound or a mixture of thermodegradable compounds which decomposes or is activated in particular at temperatures approaching the softening of the organic binder, typically at temperatures above 100.degree. C., for example between 150.degree. and 400 ° C. The intumescent agent is preferably selected from thermodegradable nitrogen compounds, thermodegradable carboxylic acids and mixtures thereof. Examples of thermodegradable nitrogen compounds include thermodegradable amides such as urea, and thermodegradable cyanamides such as melamine, guanidine and dicyandiamide, as well as ammonium, amine, amide and cyanamide salts. phosphoric, polyphosphoric or phosphonic acids. Examples of thermodegradable carboxylic acids include thermodegradable polycarboxylic acids such as oxalic acid, malonic acid, malic acid, tartaric acid, tartronic acid, maleic acid, citric acid, tricarballylic acid, 1,2,3,4-butanetetracarboxylic acid, and inorganic or organic salts thereof, especially ammonium salts, amine salts, amide salts and cyanamide salts. The intumescent agent is preferably selected from citric acid, ammonium phosphate, urea, or mixtures thereof. Intumescent layers typically comprise from 5 to 40% by weight of intumescent agent.

The intumescent layers may also comprise fillers, in particular inorganic or organometallic fillers, such as silica particles (in particular colloidal silica), silicates, precursors of sol-gel metal oxides or silane coupling agents. Intumescent layers typically comprise 1%, or even 2% to 60%, or even 50%, 40%, 20%, or even 15% by weight of fillers.

They may also comprise 1 to 15%, preferably 1 to 10%, by weight of a flame retardant. The flame retardant is preferably selected from borated compounds and organophosphorus compounds. Examples of borated compounds include boric acid or borax. Examples of organophosphorus compounds include phosphonates such as diethyl ethylphosphonate or dimethyl methylphosphonate.

The intermediate stack may be in direct contact with the first and second glass sheets. Alternatively, a holding layer may be disposed between the intermediate stack and each of the first and second sheets of glass. Thus, in a particular embodiment, the glazing according to the invention comprises a first glass sheet, a first holding layer, a first intumescent layer (or a plurality of intumescent layers), optionally a first reinforcing layer, a layer essentially inorganic, possibly a second reinforcing layer, a second intumescent layer (or a plurality of intumescent layers), a second holding layer, and a second glass sheet. The support layers are preferably based on silicates or a sol-gel material based on metal oxides, especially silica and / or titanium oxide. They typically have a thickness of 1 mhi or even 2 mhi, or 5 mih to 100 mih, or even 50 mih, 20 mih, or even 10 mih.

Each layer of the stack is preferably transparent so that the stacker typically has a total light transmittance greater than 85% and a blur of less than 15% measured by the Hazemeter according to ASTM D1003-00 with Illuminant C.

The glazing according to the invention is preferably symmetrical, that is to say that the succession of layers from the first glass sheet towards the essentially inorganic layer is identical to the succession of layers between the second glass sheet and the layer. essentially inorganic. In general, the glazing advantageously has identical fire resistance characteristics on each side.

Fig.l and 2 illustrate two embodiments of the fireproof glazing according to the invention. The intermediate stack (3) is arranged between the first glass sheet (1) and the second glass sheet (2). It comprises a first intumescent layer (4, 4a) and a second intumescent layer (5, 5a) on either side of an essentially inorganic layer (6). In the embodiment of FIG. 1, the stack comprises a single intumescent layer (4, 5) on each side of the substantially inorganic layer (6). In the embodiment of FIG. 2, the stack comprises a multitude of intumescent layers (4a, 4b, 4c and 5a, 5b, 5c) on each side of the substantially inorganic layer (6). The intumescent layers (4a, 4b, 4c and 5a, 5b, 5c) are separated from each other by secondary inorganic layers (7a, 7b and 8a, 8b).

Fig.3a to 3d illustrates the behavior of the glazing according to the invention in case of fire. Faced with the rise in temperature, the glass sheet (1) fire side breaks quickly exposing the first intumescent layer (4) (Fig.3a). The first intumescent layer (4) rapidly foams under the effect of heat to provide an opaque foam (4 ') serving as a first radiation barrier, and delaying heat transfer to the opposite side of the glazing. The integrity of the glass sheet (2) opposite the fire is thus preserved by avoiding a sudden rise in temperature in the first moments of exposure of the glazing to fire. The foam (4 ') being exposed directly to the fire is rapidly degraded, in particular when it is formed of an organic matrix. The use of a plurality of intumescent layers separated from secondary substantially inorganic thin layers, as shown in FIG. 2, has the advantage of forming a foam loaded with inorganic elements which will be degraded more slowly in the face of fire, thereby improving fire resistance properties of glazing. The combustion of the foam (4 ') exposes the essentially inorganic layer (6). This layer, which degrades at high temperature, acts primarily as a fire barrier and forms an inorganic calcining residue (6 ') ensuring the mechanical strength and the integrity of the glazing. The intumescent second layer (5), protected by the first intumescent layer and the essentially inorganic layer, undergoes a gradual increase in temperature favoring a progressive, complete and homogeneous foaming. The foam (5 ') obtained may include at least a part of the inorganic calcination residue (6'). The presence of an optional reinforcing layer (not shown) makes it possible to promote the inclusion of inorganic elements by the foam (5 ') during the foaming of the second intumescent layer (5). This foam (5 ') loaded with inorganic elements ensures the resistance and integrity of the glazing over time. In particular, it allows the maintenance of the second glass sheet (2) in case of cracking thereof. The presence of an optional retaining layer (not shown) in contact or even in direct contact with the glass sheet (2) makes it possible to improve the preservation of the integrity of the glass sheet (2) opposite to the fire.

An example of a method of manufacturing fireproof glass according to the invention is described below. This method includes providing a first sheet of glass and a second sheet of glass; and assembling the first and second glass sheets with an intermediate stack disposed therebetween, said intermediate stack comprising a first intumescent layer, an essentially inorganic layer and a second intumescent layer.

The assembly of the glass sheets with the intermediate stack can be achieved by any appropriate technique. The different layers can be deposited successively on the first glass sheet before being assembled with the second glass sheet. Alternatively, the assembly of the glass sheets with the intermediate stack comprises depositing the first intumescent layer on the first glass sheet; depositing the second intumescent layer on the second glass sheet; and assembling the thus coated glass sheets with the substantially inorganic layer. The intumescent layers are preferably deposited by wet deposition techniques, for example by spraying (spray coating), by curtain coating, by spraying (flow coating) or by application to the roll (voiler coating). The essentially inorganic layer may be deposited by roller, curtain, spray or casting application. When pouring, the coated glass sheets are arranged substantially parallel to one another and kept at a distance from each other, for example by means of a spacer frame, to form a cavity. The cavity is filled by gravity or injection with a precursor composition of the essentially inorganic layer. The assembly formed by the coated glass sheets is preferably disposed on an inclined plane or placed in a vertical position so as to avoid the presence of air in the essentially inorganic layer. A seal is generally applied to the periphery of said sheets, all the way around, while providing an opening in the thickness of the seal to allow filling of the space between the coated glass sheets. The essentially inorganic secondary layers, if present, as well as the retaining layers and the reinforcing layers, are in turn preferably deposited by roller application or by spraying because of their smaller thickness.

The first and second intumescent layers may be obtained from an aqueous dispersion of binder, especially a polymeric organic binder as defined above, comprising the intumescent agent and any fillers. It typically has a solids content of 40 to 60% by weight. A drying and / or crosslinking step may be necessary after the deposition of intumescent layers, typically at temperatures of 20 to 80 ° C for 5 minutes to 24 hours, preferably for 5 to 20 minutes.

The essentially inorganic layer can be obtained from a precursor composition. In a first particular embodiment, the precursor composition may be an aqueous solution of alkali silicates typically having a solids content of 30 to 70%. After application, the layer is dried, preferably at temperatures of 20 to 80 ° C for 10 minutes at 24h, to obtain a layer of silicates. In another particular embodiment, the precursor composition is a composition comprising a polysiloxane, a crosslinking agent and optionally a catalyst. The polysiloxane is preferably an α,--difunctionalized polydimethylsiloxane, especially with vinyl groups. The crosslinking agent is preferably a siloxane monomer such as methylsiloxane or dimethylsiloxane. The catalyst may be selected from tin catalysts. The composition typically has a solids content of 80 to 100% by weight. After application, the layer is preferably dried and / or crosslinked, typically at temperatures of 20 to 80 ° C for 10 to 120 minutes. In another embodiment, the precursor composition comprises alkoxides or metal salts, in particular of silicon and / or titanium, optionally functionalized, for example by amine, isocyanate, phosphate or fluoro groups. The composition typically has a solids content of 20 to 80%. After application, the composition is polymerized and dried, preferably at temperatures of 20 to 80 ° C for 10 minutes to 24 hours, to obtain a layer of sol-gel material.

The invention is illustrated with the following non-limiting examples.

EXAMPLES

An anti-fire glazing II according to the invention, as illustrated in FIG. 1, was prepared from two sheets of annealed, unhardened glass, 2.5 mm thick. An intumescent layer 500 μm thick was deposited on each of the glass sheets from an aqueous dispersion comprising a polymeric binder based on vinyl acetate, ethylene and vinyl ester, diethyl ethylphosphonate, ammonium phosphate, urea and citric acid. After drying the intumescent layer, the two glass sheets thus coated are arranged parallel to each other, the intumescent coatings face to face, and assembled using a peripheral seal forming a cavity 1 mm thick between the two sheets of glass. A vinyl-terminated polymethylsiloxane precursor composition, methylsiloxane and a tin catalyst is gravity fed to the full filling of the cavity. This composition is crosslinked at 60 ° C. for 1 h to form the essentially inorganic layer.

An anti-fire glazing 12 according to the invention was prepared from two sheets of annealed, unhardened glass, 2.5 mm thick. A maintenance layer based on alkali silicates was deposited on each of the glass sheets to a thickness of 5 μm. An intumescent layer 100 μm thick was deposited on each of the holding layers from an aqueous dispersion comprising a polymeric binder based on vinyl acetate, ethylene and vinyl ester, diethyl ethylphosphonate and citric acid. After drying the intumescent layer, a sol-gel silica reinforcing layer is deposited on the intumescent layer with a thickness of 5 μm. After drying of the reinforcing layer, the two sheets of glass thus coated are arranged parallel to each other, the intumescent coatings facing each other, and assembled using a peripheral seal forming a cavity of thickness 1 mm between the two glass sheets. A vinyl-terminated polymethylsiloxane precursor composition, methylsiloxane and a tin catalyst is gravity fed to the full filling of the cavity. This composition is crosslinked at 60 ° C for 1 hour to form the essentially inorganic layer.

Claims

An anti-fire glazing comprising a first non-tempered glass sheet, a second non-tempered glass sheet and a solid intermediate stack, characterized in that the intermediate stack comprises a first intumescent layer, an essentially inorganic layer and a second layer. intumescent, and in that the interlay stack has a blur of less than 15%.

2. Glazing according to claim 1, characterized in that the intermediate stack has a total light transmission of greater than 85%.

3. Glazing according to claim 1 or 2, characterized in that the intermediate stack does not comprise glass sheet.

4. Glazing according to one of claims 1 to 3, characterized in that the substantially inorganic layer is a solid layer based on inorganic polymer, silicates or a sol-gel material based on metal oxides.

5. Glazing according to one of claims 1 to 4, characterized in that the substantially inorganic layer has a thickness of 0.3 to 6.0 mm, preferably 0.3 to 3.0 mm.

6. Glazing according to one of claims 1 to 5, characterized in that the first and second intumescent layers comprise a binder and an intumescent agent.

7. Glazing according to claim 6, characterized in that the binder is an organic binder selected from homopolymers or copolymers derived from monomers or comonomers selected from vinyl monomers, diene monomers, isocyanate monomers, epoxide monomers, monomers dicarboxylic acids, monomers polyols, polyamine monomers, and mixtures thereof.

8. Glazing according to claim 6 or 7, characterized in that the intumescent agent is selected from thermodegradable nitrogen compounds, thermodegradable carboxylic acids and mixtures thereof.

9. Glazing according to one of claims 1 to 8, characterized in that the first and second intumescent layer have a thickness of 0.01 to 1.0 mm.

10. Glazing according to one of claims 1 to 9, characterized in that the first and second intumescent layer comprise charges, including inorganic or organometallic fillers.

11. Glazing according to one of claims 1 to 10, characterized in that a holding layer is disposed between the intermediate stack and each of the first and second sheet of glass.

12. Glazing according to claim 11, characterized in that the retaining layers are layers based on silicates or a sol-gel material based on metal oxides, especially silica and / or titanium oxide. .

13. Glazing according to one of claims 1 to 12, characterized in that a reinforcing layer is disposed between the substantially inorganic layer and each of the first and second intumescent layers.

14. Glazing according to claim 13, characterized in that the reinforcing layers are layers based on silicates or a sol-gel material based on metal oxides, especially silica and / or titanium oxide. .

15. Glazing according to one of claims 1 to 14, characterized in that the spacer stack comprises a plurality of intumescent layers on each side of the substantially inorganic layer, the pluralities of intumescent layers being separated from each other by substantially inorganic secondary layers.