Fire-resistant glazing

Abstract

The present invention relates to fire-resistant glazing comprising two glazed walls forming a cavity between them, characterized in that the cavity comprises a hydrogel having: - a content F of less than or equal to 50%, after heating the hydrogel at 400°C for t = 15 minutes, and - a content F of less than or equal to 100%, after heating the hydrogel at 400°C for t = 45 minutes, the content F being defined by the following equation: F (%) = 100 x [(m0 – mt) / ma] where: m0 is the initial mass of the hydrogel, mt is the mass of the hydrogel after heating at 400°C for a time t, and ma is the initial mass of water in the hydrogel. The invention further relates to a method for manufacturing such glazing.

Description

[0001] Description

[0002] Title: Fire-resistant glazing

[0003] The present invention belongs to the general field of glazing manufacturing. It relates more particularly to fire-resistant glazing comprising a hydrogel, as well as to a method for manufacturing such glazing. The invention finds a particularly advantageous, although in no way limiting, application in the case of exterior glazing or interior glazing.

[0004] Glazing units, such as insulated glass units (IGUs), are widely used in both domestic and industrial applications, and as both exterior and interior glazing.

[0005] Generally, glazing is not well-suited to environments where there is a risk of fire. Glazing generally suffers from poor fire resistance, particularly due to its sensitivity to thermal shock. This poses a real problem when considering the safety of building users in the event of a fire. Furthermore, safety regulations are increasingly imposing restrictions on the fire resistance of glazing used in certain environments.

[0006] The fire resistance of glazing is generally determined according to three criteria. The first criterion, denoted E, reflects the mechanical resistance, the flame resistance and the capacity to retain smoke in a given volume, by a containment screen. The second criterion, denoted EW, includes the criterion E as well as the limitation of radiation, evaluated by measuring the time during which the radiation emerging from the face not exposed to the fire does not exceed a certain threshold. The third criterion, denoted El, includes the criterion EW as well as the thermal insulation, evaluated by measuring the time during which the temperature on the face not exposed to the fire does not exceed a certain threshold.

[0007] Many fire-resistant glazings are described in the prior art. Glazings comprising silicate-based interlayers are known, such as those described in patent application EP 0951388. However, these glazings have several drawbacks, in particular, their weight is high and their environmental impact is high. In addition, silicate layers tend to creep over time, which causes a decrease in transparency. An improvement has been made by replacing the silicate layer with a hydrogel.

[0008] Indeed, in addition to improved fire performance, hydrogel-based fire-resistant glazing has the advantage of being more stable over time, less expensive, and easier to manufacture. Given increasingly strict regulations, it is necessary to develop glazing with improved fire performance.

[0009] In this context, the inventors have demonstrated that the fire-resistant performance of hydrogel-based glazing can be improved by controlling its foaming capacity. Indeed, upon exposure to fire, after rupture of the glazed wall in contact with the fire, an expansion of the hydrogel occurs, and bubbles form, thus releasing the water from the hydrogel in a controlled manner in the form of vapor. The thermal energy absorbed by the hydrogel during this phenomenon prevents an increase in temperature, and thus provides protection on the side of the glazing not exposed to the fire.

[0010] The inventors observed that a hydrogel with a low foaming capacity lost its water content too quickly and therefore provided insufficient or shorter protection in the event of fire exposure. It was also found that a hydrogel with too high a foaming capacity formed bubbles that were too large, causing the water content to be released more easily and more quickly, which also resulted in a shorter fire protection time.

[0011] The inventors demonstrated that the foaming capacity of the hydrogel could be controlled using a specific parameter.

[0012] The inventors therefore sought to optimize this foaming capacity, while ensuring that the other properties of the hydrogel that contribute to fire-resistant performance are maintained. In particular, it is advantageous for the hydrogel to have suitable mechanical strength.

[0013] Thus, it was demonstrated that optimal fire-resistant performance was achieved for a hydrogel having:

[0014] - an F rate less than or equal to 50%, after heating the hydrogel to 400°C for t=15 minutes, and

[0015] - an F rate less than or equal to 100%, after heating the hydrogel to 400°C for t=45 minutes.

[0016] The F rate, which reflects water loss, is defined by the following equation:

[0017] [Eq 1]

[0018] F (%) = 100 x [(m0- m t ) / m a ] where: mo is the initial mass of the hydrogel, m t is the mass of the hydrogel after heating at 400°C for a time t, and m a is the initial mass of water in the hydrogel.

[0019] Thus, the present invention relates to a fire-resistant glazing comprising a first and a second glazed wall forming between them a first cavity, in which the first cavity comprises a hydrogel having:

[0020] - an F rate less than or equal to 50%, after heating the hydrogel to 400°C for t=15 minutes, and

[0021] - an F rate less than or equal to 100%, after heating the hydrogel to 400°C for t=45 minutes, where the F rate is defined by the following equation:

[0022] [Eq 2]

[0023] F (%) = 100 x [(m0- m t ) / m a ] where: mo is the initial mass of the hydrogel, m t is the mass of the hydrogel after heating at 400°C for a time t, and m a is the initial mass of water in the hydrogel.

[0024] The present invention also relates to a method for manufacturing a glazing as defined in the present application, comprising: i) providing a first and a second glazed wall, ii) arranging the first and second glazed walls so as to form a first cavity between them, iii) introducing a gelling composition into the first cavity, and iv) polymerizing the gelling composition, to form a hydrogel.

[0025] FIGURES

[0026] [Fig 1]: Examples of hydrogels with their foaming score.

[0027] DETAILED DESCRIPTION

[0028] Hydrogel

[0029] The fire-resistant glazing according to the invention comprises a hydrogel having particular characteristics giving the glazing fire-resistant properties. As used in the present application, the term "hydrogel" denotes a hydrated gel comprising a hydrophilic polymer network. Generally, a hydrogel is formed by polymerization, typically by heating or irradiation (for example, UV irradiation), generally in the presence of a polymerization initiator or catalyst, of a gelling composition comprising:

[0030] - a crosslinkable compound capable of forming a hydrogel,

[0031] - one or more salts,

[0032] - one or more crosslinking agents,

[0033] - an aqueous vehicle, and

[0034] - optionally one or more initiators and / or polymerization catalysts (preferably one or more initiators).

[0035] As used herein, "crosslinkable compound capable of forming a hydrogel" means any compound or mixture of compounds capable of forming the crosslinked polymer network of the hydrogel during the curing of the gelling composition comprising it.

[0036] The crosslinkable compound capable of forming a hydrogel is typically an organic compound.

[0037] The crosslinkable compound capable of forming a hydrogel generally comprises a hydrophilic polymerizable monomer (or a mixture of hydrophilic polymerizable monomers) and / or a hydrophilic prepolymer (or a mixture of hydrophilic prepolymers).

[0038] The hydrophilic polymerizable monomer may be chosen from monomers carrying an ionizable group, in particular a carboxylic, sulfonic, or phosphoric acid group. The hydrophilic polymerizable monomer may be chosen from monomers carrying a derivatized group that can be easily converted - for example by hydrolysis - into a carboxylic acid. Examples of such derivatized groups are, in particular, an ester, an amide, a nitrile, or an anhydride.

[0039] Typically, the hydrophilic polymerizable monomer may be chosen from vinyl monomers carrying an ionizable group, in particular a carboxylic, sulfonic, or phosphoric acid group, or a derivative group which can be easily converted - for example by hydrolysis - into a carboxylic acid.

[0040] The hydrophilic polymerizable monomer may be a vinyl monomer bearing a carboxylic acid group, or a derivative group which can be easily converted - for example by hydrolysis - into a carboxylic acid (such as an ester or an amide). Advantageously, the hydrophilic polymerizable monomer is an acrylic or alkylacrylic monomer (or a salt thereof, or an ester or amide derivative thereof), in particular a compound of formula (I): H2C=C(R 1 )-HORN 2 (I), where R 1 is hydrogen, alkyl, or -CH2CO2H, and R 2is -OH, -O-(alkyl), -NH2, -NH(alkyl), or -N(alkyl)2, or a salt thereof. The term "alkyl" (as such or in the aforementioned groups comprising it) herein preferably refers to a C1-C5 alkyl, more preferably a methyl or an ethyl, or even to a methyl. Said "alkyl", as such or in the aforementioned groups comprising it, is optionally substituted by an OH, -N(CH3)2 or -N(CH2- CH3)2 group. The salt may in particular be an alkali metal or alkaline earth metal salt.

[0041] More preferably, the hydrophilic polymerizable monomer is a compound of formula (I) chosen from acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N,N-diethylacrylamide, N-methylmethacrylamide, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, methylolacrylamide, their salts and their mixtures.

[0042] A preferred compound of formula (I) is selected from acrylamide, methylacrylamide, and methylolacrylamide.

[0043] The hydrophilic polymerizable monomer may be a vinyl monomer bearing a sulfonic or phosphoric group. Examples of such monomers include vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, vinyl phosphoric acid, ethylene oxide-modified phosphoric acid (meth)acrylate, and mixtures thereof.

[0044] Advantageously, the hydrophilic polymerizable monomer is an unsaturated carboxylic acid (in particular, an aliphatic unsaturated carboxylic acid, such as an acrylic, methacrylic or itaconic acid) carrying a sulfonic acid group, where the sulfonic acid group is in the form of a salt, ester, amide or betaine.

[0045] More particularly, the hydrophilic polymerizable monomer may be a vinyl monomer bearing a carboxylic acid, ester, or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof (preferably an ester or a salt, better still a salt thereof). Such a monomer may in particular be of formula (II):

[0046] H2C=C(R 3 )-C(O)-XR 4 -SO3H (II) where: - X is -O- or -NH-,

[0047] - R 3 is hydrogen, optionally substituted alkyl (e.g., methyl or ethyl), or a group of formula -CH2-C(O)-OR 4 -SO3-, and

[0048] - R 4 is an optionally substituted alkylene group (e.g., C1-C5 alkylene, such as propylene), a group of formula -CH2-CH2-N(CH3)2 + -CH2-CH2-CH2- or -CH2-CH2-CH2-N(CH3)2 + -CH2-CH2-

[0049] CH2-, or a salt thereof.

[0050] In some embodiments, R 3 is hydrogen, methyl, ethyl, propyl, isopropyl or 2-hydroxypropyl.

[0051] In some embodiments, R 4 is -CH2-, -CH2-CH2-, -CH(CH3)-CH2-, -CH2-CH(OH)-CH2-, -C(CH3)2- CH2- OR -C(CH3)(phenyl)-CH2.

[0052] Alkylsulfonic acid salts include sodium or potassium salts. Alkylsulfonic acid esters include methyl, ethyl, or propyl esters.

[0053] Preferably, the hydrophilic polymerizable monomer is a compound of formula (II) chosen from:

[0054] - 3-sulfopropylacrylate,

[0055] - 2-acrylamido-2-methylpropanesulfonic acid,

[0056] - 2-acrylamido-2-phenylpropanesulfonic acid,

[0057] - 3-sulfopropylmethacrylate,

[0058] - N,N-dimethyl-N-(2-methacryloxyethyl)-N-(3-sulfopropylammonium) betaine,

[0059] - 3-sulfopropyl diester of itaconic acid,

[0060] - their mixtures, and

[0061] - a salt (particularly potassium or sodium) thereof.

[0062] A preferred compound of formula (II) is selected from 2-acrylamido-2-methylpropanesulfonic acid, a salt of 2-acrylamido-2-methylpropanesulfonic acid, and 3-sulfopropylacrylate.

[0063] The crosslinkable compound capable of forming a hydrogel may be: i) a vinyl monomer bearing a carboxylic acid, ester or amide group, ii) a vinyl monomer bearing a carboxylic acid, ester or amide group, wherein said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, or

[0064] - a mixture of these.

[0065] More particularly, the crosslinkable compound capable of forming a hydrogel may be a mixture of: i) a vinyl monomer bearing a carboxylic acid group, or a derived group that can be easily converted (for example by hydrolysis) into a carboxylic acid, typically an ester or amide, for example a compound of formula (I) as described above or a salt thereof; and ii) a vinyl monomer bearing a carboxylic acid, ester, or amide group, wherein said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof (preferably an ester or a salt, more preferably a salt thereof), for example a compound of formula (II) as described above or a salt thereof. It is understood that the monomers i) and ii) are different from each other. In particular, the monomer i) is not substituted by an alkylsulfonic acid group.

[0066] The weight ratio of the amount of monomer i) to the amount of monomer ii) is advantageously from 0.01 to 2, preferably from 0.05 to 1, better still from 0.1 to 0.5, or even from 0.1 to 0.2.

[0067] The polymerizable monomer may be an allyl alcohol-based sulfonate ether or polyether, such as the sodium or potassium salts of 3-(allyloxy)-2-hydroxypropanesulfonate or polyethylene glycol allyl-(3-sulfopropyl)diether.

[0068] In some embodiments, the crosslinkable compound capable of forming a hydrogel comprises one or more ionizable hydrophilic polymerizable monomers (such as the aforementioned acid monomers) and one or more non-ionizable polymerizable monomers.

[0069] The hydrophilic prepolymers may be chosen from vinyl polymers carrying ionizable groups, in particular ionizable acid groups. The hydrophilic prepolymers may be homopolymers or copolymers. The prepolymers may be chosen from polyacids, polyalcohols, or their salts. More particularly, the prepolymers may be chosen from polyacrylic acid or polyalkylacrylic acid (e.g. methacrylic or ethacrylic acid).

[0070] The weight content of crosslinkable compound capable of forming a hydrogel is generally 4 to 40% by weight, relative to the total weight of the gelling composition. The weight content of crosslinkable compound capable of forming a hydrogel may for example be 4 to 30% by weight, 6 to 20% by weight, 8 to 15% by weight, or 4 to 10% by weight relative to the total weight of the gelling composition.

[0071] The (or each) salt included in the gelling composition may be an organic or inorganic salt. Generally, the (or each) salt consists of a metal or ammonium cation and an organic or inorganic anion. Examples of metal cations include alkali metal cations (e.g. sodium, potassium, lithium), alkaline earth metal cations (e.g. calcium, magnesium, barium), transition metal cations (e.g. copper, zinc).

[0072] Examples of inorganic or organic anions include acetate, halide (eg chloride), oxide, hydroxide, sulfate, nitrate, borate, or silicate anions.

[0073] Preferably, the (or each) salt is chosen from: potassium chloride, sodium chloride, barium chloride, calcium chloride, magnesium chloride, magnesium oxide, magnesium sulfate, magnesium acetate, sodium hydroxide, and mixtures thereof.

[0074] The weight content of salts (not including any salts of crosslinkable compound capable of forming the hydrogel) is generally 10 to 60% by weight, for example 10 to 50% by weight, 10 to 40% by weight, 10 to 30% by weight, 15 to 30% by weight, 15 to 25% by weight, 20 to 60% by weight, 30 to 50% by weight, or 40 to 50% by weight, relative to the total weight of the gelling composition.

[0075] The aqueous vehicle of the gelling composition acts as a vehicle for the other ingredients of the gelling composition, and allows the latter to flow and thus be poured or injected into the cavity of the glazing during its manufacture.

[0076] The aqueous vehicle comprises water, and may optionally comprise another water-miscible solvent compatible with the formation of the hydrogel. Such a solvent is typically a C1-C4 alcohol (such as methanol, ethanol, propanol, isopropanol), a glycol, a ketone, an amide, or a urea. Advantageously, the aqueous vehicle comprises from 75 to 100% by weight, preferably from 90 to 100% by weight, or even from 98 to 100% by weight of water.

[0077] The weight content of aqueous vehicle is generally 40 to 90% by weight, for example 50 to 90% by weight, 60 to 90% by weight, 40 to 80% by weight, or 40 to 70% by weight, relative to the total weight of the gelling composition.

[0078] The gelling composition further comprises one or more crosslinking agents. The crosslinking agent facilitates the crosslinking of the polymer chains during the polymerization of the gelling composition. The crosslinking agent may be involved in the formation of the covalent bond between the polymer chains by being incorporated therein. The crosslinking agent may be a monomer comprising at least two unsaturations (typically a carbon-carbon double bond).

[0079] More particularly, the crosslinking agent may be chosen from:

[0080] N,N'-methylenebisacrylamide, N,N'-diallyl-L-tartardiamide, N,N-diallylacrylamide, triacrylformal, N,N-diacryloylimide, N,N-dimethacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, trimethylolethane triacrylate, tetramethylolmethane tetramethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane triacrylate, tetramethylolmethane tetramethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane tetra ... tetramethylolmethane, divinylbenzene, diallylphthalate, urethane (meth)acrylate, polyester (meth)acrylate, epoxyacrylate, and mixtures thereof.

[0081] The crosslinking agent may be an N-alkoxymethyl(meth)acrylamide, such as N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-tertbutoxymethyl(meth)acrylamide, or N-hydroxymethyl(meth)acrylamide.

[0082] The weight content of crosslinking agent is generally 0.001 to 1% by weight, for example 0.05 to 0.5% by weight, 0.01 to 0.1% by weight, or 0.01 to 0.06% by weight, relative to the total weight of the gelling composition.

[0083] The gelling composition may further comprise one (or more) initiator. The initiator facilitates polymerization during polymerization of the gelling composition. The initiator may be a thermal initiator (i.e. activated by heating) or a photoinitiator (i.e. activated by irradiation, in particular UV irradiation).

[0084] The choice of the initiator depends in particular on its solubility, pH, hydrogel formation temperature, irradiation wavelength (for the photoinitiator).

[0085] Regarding photoinitiators, there are many commercially available, including those in the Irgacure® range (BASF). Benzoyl peroxide, hydrogen peroxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone and alpha-ketoglutaric acid are also examples of photoinitiators.

[0086] Examples of thermoinitiators include: sodium or potassium persulfate, ammonium persulfate, sodium or potassium thiosulfate, 4,4-azobis(4-cyanovaleric acid), 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate, 2,2'-azobis(2-methylpropionamidine)dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate, 2,2'-azobis{2-[l-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-Azobis(l-imino-l-pyrrolidino-2-ethylpropane) dihydrochloride, 2,2'-azobis{2-methyl-N-[l,l- bis(hydroxymethyl)-2-hydroxyethl]propionamide}, or 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide.

[0087] The weight content of initiators (when present) is generally 0.0001 to 0.1% by weight, for example 0.001 to 0.05% by weight, or 0.01 to 0.05% by weight, relative to the total weight of the gelling composition.

[0088] The gelling composition may further comprise a coupling agent. The coupling agent facilitates the bonding between the hydrogel and the surface of the glass walls of the glazing.

[0089] Generally, the coupling agent is a silane. More particularly, the coupling agent may be a silane comprising a vinyl, alkenyl, alkynyl or acrylate group.

[0090] Examples of coupling agents include: vinyltrichorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriisopropylsilane, vinyltris(tert-butylperoxy)silane, vinyldimethylchlorosilane, vinyldimethoxysilane, vinyldichlorosilane, vinylmethyldimethoxysilane, vinyldiethoxysilane, (methacryloxymethyl)methyldimethoxysilane, methacryloxymethyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, or vinyltriacetoxysilane.

[0091] The coupling agent may be an organic titanate or zirconate. Such compounds are notably described in patent application US4264681.

[0092] The weight content of coupling agents is generally 0.01 to 2% by weight, for example 0.05 to 1% by weight, relative to the total weight of the gelling composition.

[0093] The gelling composition may further comprise one (or more) polymerization catalysts. The catalyst may, for example, be an amine (such as triethylamine, triethanolamine, diethylamine, dimethylaminopyridine, N-methylmorpholine, piperidine, N,N-diisopropylethylamine, or tetramethylethylenediamine), sodium bisulfite, sodium metabisulfite, ammonium iron sulfate, or copper sulfate.

[0094] An example of a preferred catalyst is triethylamine.

[0095] The weight content of catalysts (when present) is generally 0.0001 to 0.1% by weight, for example 0.001 to 0.05% by weight, or 0.01 to 0.05% by weight, relative to the total weight of the gelling composition.

[0096] In the present application, the weight content of a constituent (e.g. crosslinkable compound capable of forming a hydrogel, salt, crosslinking agent, etc.) corresponds to the weight of the constituent relative to the total weight of the composition. The weight of the constituent corresponds to the weight of the constituent itself, and therefore, to its weight in dry extract when it is in particular diluted in a dispersion or solution. Also, when the constituent is a salt used in the form of a hydrate, the weight content is expressed for the anhydrous salt.

[0097] Advantageously, the gelling composition comprises, relative to the total weight of the composition:

[0098] - 4 to 40% (for example 4 to 15%) by weight of one or more crosslinkable compounds capable of forming a hydrogel,

[0099] - 10 to 60% (for example 15 to 30%) by weight of one or more salts,

[0100] - 0.001 to 1% (for example 0.02 to 0.8%) by weight of one or more crosslinking agents,

[0101] - 40 to 90% (e.g. 60 to 80%) by weight of an aqueous vehicle, and

[0102] - optionally 0.001 to 0.1% (for example 0.01 to 0.08%) by weight of one or more polymerization initiators and / or catalysts (preferably one or more initiators).

[0103] More particularly, the gelling composition may comprise, relative to the total weight of the composition:

[0104] - 4 to 10% by weight of one or more crosslinkable compounds capable of forming a hydrogel,

[0105] - 15 to 25% by weight of one or more salts,

[0106] - 0.03 to 0.5% (for example 0.03 to 0.08%) by weight of one or more crosslinking agents,

[0107] - 65 to 75% by weight of an aqueous vehicle, and

[0108] - optionally 0.02 to 0.06% by weight of one or more polymerization initiators and / or catalysts (preferably one or more initiators).

[0109] In certain embodiments, the gelling composition comprises, relative to the total weight of the composition: - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of one or more crosslinkable compounds capable of forming a hydrogel chosen from: i) a vinyl monomer bearing a carboxylic acid, ester or amide group, ii) a vinyl monomer bearing a carboxylic acid, ester or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, or

[0110] - a mixture of these;

[0111] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from: potassium chloride, sodium chloride, barium chloride, calcium chloride, magnesium chloride, magnesium oxide, magnesium sulfate, magnesium acetate, sodium hydroxide, and mixtures thereof;

[0112] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of one or more crosslinking agents chosen from: N,N'-methylenebisacrylamide, N,N'-diallyl-L-tartardiamide, N,N-diallylacrylamide, triacrylformal, N,N-diacryloylimide, N,N-dimethacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, trimethylolethane triacrylate, tetramethylolmethane tetramethacrylate, tetramethylolmethane triacrylate,divinylbenzene, diallylphthalate, urethane (meth)acrylate, polyester (meth)acrylate, epoxyacrylate, and mixtures thereof, preferably N,N'-methylenebisacrylamide or N,N'-diallyl-L-tartardiamide;,

[0113] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0114] - optionally 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0115] It is understood that monomers i) and ii) are different from each other. In particular, monomer i) is not substituted by an alkylsulfonic acid group.

[0116] When they are mixed, the weight ratio of the quantity of monomer i) to the quantity of monomer ii) is advantageously from 0.01 to 2, preferably from 0.05 to 1, better still from 0.1 to 0.5, or even from 0.1 to 0.2. In certain embodiments, the gelling composition comprises, relative to the total weight of the composition:

[0117] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, amide, or ester group, preferably a compound of formula (I) as defined above or a salt thereof,

[0118] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from: potassium chloride, sodium chloride, barium chloride, calcium chloride, magnesium chloride, magnesium oxide, magnesium sulfate, magnesium acetate, sodium hydroxide, and mixtures thereof;

[0119] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of one or more crosslinking agents chosen from: N,N'-methylenebisacrylamide, N,N'- diallyl-L-tartardiamide, N,N-diallylacrylamide, triacrylformal, N,N-diacryloylimide, N,N- dimethacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, trimethylolethane triacrylate, tetramethylolmethane tetramethacrylate, tetramethylolmethane triacrylate,divinylbenzene, diallylphthalate, urethane (meth)acrylate, polyester (meth)acrylate, epoxyacrylate, and mixtures thereof, preferably N,N'-methylenebisacrylamide or N,N'-diallyl-L-tartardiamide;,

[0120] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0121] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0122] Preferably, the gelling composition comprises, relative to the total weight of the composition:

[0123] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, amide, or ester group, preferably a compound of formula (I) as defined above or a salt thereof,

[0124] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from: sodium chloride, magnesium chloride, sodium hydroxide, and mixtures thereof;

[0125] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, more preferably 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide or N,N'-diallyl-L-tartardiamide; - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0126] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0127] Better still, the gelling composition includes, relative to the total weight of the composition:

[0128] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, amide, or ester group, preferably a compound of formula (I) as defined above or a salt thereof,

[0129] - 15 to 22% magnesium chloride and / or sodium chloride and possibly 0.001% to 3% sodium hydroxide;

[0130] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0131] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0132] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0133] Better still, the gelling composition includes, relative to the total weight of the composition:

[0134] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a compound chosen from acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N,N-diethylacrylamide, N-methylmethacrylamide, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, methylolacrylamide, their salts and their mixtures;

[0135] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from: sodium chloride, magnesium chloride, sodium hydroxide, and mixtures thereof;

[0136] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0137] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0138] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate. In a particular embodiment, the gelling composition comprises, relative to the total weight of the composition:

[0139] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, amide, or ester group, preferably a compound of formula (I) as defined above or a salt thereof,

[0140] - 15 to 22% magnesium chloride and / or sodium chloride and possibly 0.001% to 3% sodium hydroxide;

[0141] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-diallyl-L-tartardiamide;

[0142] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0143] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0144] In certain embodiments, the gelling composition comprises, relative to the total weight of the composition:

[0145] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, ester, or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0146] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from: potassium chloride, sodium chloride, barium chloride, calcium chloride, magnesium chloride, magnesium oxide, magnesium sulfate, magnesium acetate, sodium hydroxide, and mixtures thereof;

[0147] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of one or more crosslinking agents chosen from: N,N'-methylenebisacrylamide, N,N'- diallyl-L-tartardiamide, N,N-diallylacrylamide, triacrylformal, N,N-diacryloylimide, N,N- dimethacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, trimethylolethane triacrylate, tetramethylolmethane tetramethacrylate, tetramethylolmethane triacrylate,divinylbenzene, diallylphthalate, urethane (meth)acrylate, polyester (meth)acrylate, epoxyacrylate, and mixtures thereof, preferably N,N'-methylenebisacrylamide or N,N'-diallyl-L-tartardiamide;,

[0148] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0149] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0150] Preferably, the gelling composition comprises, relative to the total weight of the composition:

[0151] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, ester, or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0152] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from sodium chloride, magnesium chloride, sodium hydroxide, and mixtures thereof;

[0153] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0154] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0155] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0156] Better still, the gelling composition includes, relative to the total weight of the composition:

[0157] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, ester, or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0158] - 15 to 22% magnesium chloride and / or sodium chloride and possibly 0.001% to 3% sodium hydroxide;

[0159] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0160] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water;

[0161] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate. Better still, the gelling composition comprises, relative to the total weight of the composition:

[0162] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a compound chosen from: 3-sulfopropylacrylate, 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 3-sulfopropylmethacrylate, N,N-dimethyl-N-(2-methacryloxyethyl)-N-(3-sulfopropylammonium) betaine, 3-sulfopropyl diester of itaconic acid, a salt thereof, and mixtures thereof;

[0163] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from sodium chloride, magnesium chloride, sodium hydroxide, and mixtures thereof;

[0164] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0165] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0166] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0167] In a particular embodiment, the gelling composition comprises, relative to the total weight of the composition:

[0168] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a vinyl monomer carrying a carboxylic acid, ester, or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0169] - 15 to 22% magnesium chloride and / or sodium chloride and possibly 0.001% to 3% sodium hydroxide;

[0170] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, more preferably 0.03 to 0.08%) by weight of N,N'-diallyl-L-tartardiamide;

[0171] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water;

[0172] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0173] In certain embodiments, the gelling composition comprises, relative to the total weight of the composition:

[0174] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a mixture of: i) a vinyl monomer carrying a carboxylic acid, ester or amide (preferably amide) group, preferably a compound of formula (I) as defined above or a salt thereof, and ii) a vinyl monomer carrying a carboxylic acid, ester or amide group, wherein said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0175] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from: potassium chloride, sodium chloride, barium chloride, calcium chloride, magnesium chloride, magnesium oxide, magnesium sulfate, magnesium acetate, sodium hydroxide, and mixtures thereof;

[0176] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of one or more crosslinking agents chosen from: N,N'-methylenebisacrylamide, N,N'- diallyl-L-tartardiamide, N,N-diallylacrylamide, triacrylformal, N,N-diacryloylimide, N,N- dimethacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, trimethylolethane triacrylate, tetramethylolmethane tetramethacrylate, tetramethylolmethane triacrylate,divinylbenzene, diallylphthalate, urethane (meth)acrylate, polyester (meth)acrylate, epoxyacrylate, and mixtures thereof, preferably N,N'-methylenebisacrylamide or N,N'-diallyl-L-tartardiamide;,

[0177] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0178] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0179] The weight ratio of the amount of monomer i) to the amount of monomer ii) is advantageously from 0.01 to 2, preferably from 0.05 to 1, better still from 0.1 to 0.5, or even from 0.1 to 0.2.

[0180] Preferably, the gelling composition comprises, relative to the total weight of the composition:

[0181] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a mixture of: i) a vinyl monomer carrying a carboxylic acid, ester or amide (preferably amide) group, preferably a compound of formula (I) as defined above or a salt thereof, and ii) a vinyl monomer carrying a carboxylic acid, ester or amide group, wherein said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0182] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from sodium chloride, magnesium chloride, sodium hydroxide, and mixtures thereof;

[0183] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0184] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0185] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0186] The weight ratio of the amount of monomer i) to the amount of monomer ii) is advantageously from 0.01 to 2, preferably from 0.05 to 1, better still from 0.1 to 0.5, or even from 0.1 to 0.2.

[0187] Better still, the gelling composition includes, relative to the total weight of the composition:

[0188] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a mixture of: i) a vinyl monomer carrying a carboxylic acid, ester or amide (preferably amide) group, preferably a compound of formula (I) as defined above or a salt thereof, and ii) a vinyl monomer carrying a carboxylic acid, ester or amide group, wherein said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, preferably a compound of formula (II) as defined above or a salt thereof;

[0189] - 15 to 22% magnesium chloride and / or sodium chloride and possibly 0.001% to 3% sodium hydroxide;

[0190] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0191] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0192] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0193] Better still, the gelling composition includes, relative to the total weight of the composition:

[0194] - 4 to 40% (for example 4 to 15%, preferably 4 to 10%) by weight of a mixture of: i) a compound chosen from acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N,N-diethylacrylamide, N-methylmethacrylamide, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, methylolacrylamide, their salts and their mixtures; and ii) a compound selected from: 3-sulfopropylacrylate, 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 3-sulfopropylmethacrylate, N,N-dimethyl-N-(2-methacryloxyethyl)-N-(3-sulfopropylammonium) betaine, 3-sulfopropyl diester of itaconic acid, their salts, and their mixtures;

[0195] - 10 to 60% (for example 15 to 30%, preferably 15 to 25%) by weight of one or more salts chosen from sodium chloride, magnesium chloride, sodium hydroxide, and mixtures thereof;

[0196] - 0.001 to 1% (for example 0.02 to 0.8%, preferably 0.03 to 0.5%, better still 0.03 to 0.08%) by weight of N,N'-methylenebisacrylamide;

[0197] - 40 to 90% (for example 60 to 80%, preferably 65 to 75%) by weight of water; and

[0198] - optionally, 0.001 to 0.1% (for example 0.01 to 0.08%, preferably 0.02 to 0.06%) by weight of one or more polymerization initiators and / or catalysts, preferably one or more initiators such as a persulfate.

[0199] The weight ratio of the amount of monomer i) to the amount of monomer ii) is advantageously from 0.01 to 2, preferably from 0.05 to 1, better still from 0.1 to 0.5, or even from 0.1 to 0.2.

[0200] In a particular embodiment, the gelling composition is free of polyethylene glycol diacrylate.

[0201] The gelling composition is typically formed by mixing the various ingredients in the aqueous vehicle.

[0202] The gelling composition is usually presented in the form of a liquid.

[0203] The polymerization of the gelling composition can be carried out by heating or irradiation (for example, UV irradiation) of the gelling composition, generally in the presence of a polymerization initiator and / or catalyst.

[0204] The hydrogel of the glazing according to the invention has:

[0205] - an F rate less than or equal to 50%, after heating the hydrogel to 400°C for t=15 minutes, and

[0206] - an F rate less than or equal to 100%, after heating the hydrogel to 400°C for t=45 minutes. The F rate, expressed in %, is defined by the following equation:

[0207] [Eq 3]

[0208] F (%) = 100 x [(m0- m t ) / m a ] where: mo is the initial mass of the hydrogel, m t is the mass of the hydrogel after heating at 400°C for a time t, and m a is the initial mass of water in the hydrogel.

[0209] The masses required to calculate the F rate are measured by weighing the hydrogel. In particular, m t is measured by weighing the hydrogel after heating at 400°C for a time t.

[0210] The F rate reflects the water loss when the hydrogel is subjected to heating at 400°C. It is considered that, under these heating conditions, the hydrogel has lost:

[0211] - essentially water as long as its F rate is less than or equal to 100%, and

[0212] - all of its water as well as the organic matter it contains when the F rate is greater than 100%.

[0213] A loss of organic matter reflects a degradation of the hydrogel.

[0214] Advantageously, the F rate after heating the hydrogel to 400°C for t=15 minutes is less than or equal to 48%.

[0215] Advantageously, the F rate after heating the hydrogel to 400°C for t=45 minutes is less than or equal to 98%.

[0216] Typically, the F rate after heating the hydrogel at 400°C for t=15 minutes is greater than 20%, notably greater than 30%, or even greater than 40%.

[0217] Typically, the F rate after heating the hydrogel at 400°C for t=45 minutes is greater than 60%, notably greater than 70%, or even greater than 80%.

[0218] Advantageously, the F rate after heating the hydrogel to 400°C for t=30 minutes is less than or equal to 90%, preferably less than or equal to 88%.

[0219] Advantageously, the hydrogel has a compressive modulus of elasticity E2 of 10 to 80 kPa, preferably 10 to 75 kPa, more preferably 10 to 50 kPa, or even 10 to 40 kPa, very particularly 10 to 25 kPa, better still 10 to 20 kPa, the compressive modulus of elasticity E2 being determined for a deformation of 4 to 6 mm on a sample of 35x35x17 mm (where 17 mm is the thickness of the hydrogel). Even more preferably, said compressive modulus of elasticity E2 is 11 to 19 kPa, for example 12 to 18 kPa, or 13 to 16 kPa.

[0220] Adjusting the compressive modulus of elasticity, particularly the compressive modulus E2 of the hydrogel, can optimize the fire-resistant properties of the hydrogel, including its mechanical strength. For example, for a compressive modulus E2 of less than 10 kPa, the hydrogel has low mechanical strength, which generally causes the hydrogel to flow. For a compressive modulus E2 of greater than 80 kPa, the hydrogel has high mechanical strength, which generally prevents good circulation of water before rupture of the glass wall exposed to fire, causing hot spots. Advantageously, adjusting the compressive modulus of elasticity, particularly the compressive modulus E2 of the hydrogel, can also optimize the foaming capacity of the hydrogel.

[0221] Advantageously, the hydrogel also has an initial compressive modulus of elasticity El of 3 to 30 kPa, preferably 3 to 25 kPa, better still 3 to 20 kPa, or even 3 to 15 kPa, or even 4 to 10 kPa. The initial compressive modulus of elasticity El is determined for a deformation of 0 to 2 mm on a sample of 35x35x17 mm (where 17 mm is the thickness of the hydrogel).

[0222] For a given hydrogel, the initial compressive modulus of elasticity El is lower than the compressive modulus of elasticity E2.

[0223] Adjusting the said penetration force of the hydrogel also helps to optimize the fire-resistant properties of the hydrogel.

[0224] Preferably, said penetration force is 5 to 20 N, preferably 6 to 15 N, or even 6 to 12 N.

[0225] Advantageously, the penetration distance at rupture of the hydrogel is 10 to 35 mm, preferably 15 to 30 mm, or even 20 to 30 mm.

[0226] The hydrogel of the glazing according to the invention is preferably transparent.

[0227] In the present application, the term "transparent" means that the object to which this term is attached (e.g. hydrogel, glazed wall, glazing) has a light transmission coefficient greater than 60%, typically greater than 70%, preferably greater than 80%, better still greater than 90%, or even greater than 95%. The light transmission coefficient can be determined according to standard EN410. The hydrogel of the glazing according to the invention is advantageously non-diffusing.

[0228] In the present application, the term “non-diffusing” means that the object to which this term is attached (e.g. hydrogel, glass wall, glazing) has a haze of less than 20%, advantageously less than 15%, preferably less than 10%, better still less than 5%. Haze is defined and measured according to the ASTD D1003 standard.

[0229] The hydrogel of the glazing according to the invention is advantageously colorless. In particular, in the CIELAB color space, the hydrogel advantageously has a b* value of less than 3, preferably less than 2, or even less than 1.5, for example between 0 and 1.

[0230] In the CIELAB color space, the hydrogel advantageously has an a* value less than 2, preferably less than 1, or even less than 0, for example between -5 and -0.5.

[0231] In the CIELAB color space, the hydrogel advantageously has an L* value greater than 80, preferably greater than 90, or even greater than 95.

[0232] The various parameters defined above can in particular be determined according to the methods described in the examples below.

[0233] The parameters of the hydrogel used in the glazing according to the invention can be controlled in particular by adjusting the relative quantities of the constituents of the gelling composition, in particular, the relative quantities of crosslinkable compound capable of forming a hydrogel, salts, initiator (if present), and crosslinking agent. For example: i) the salt content generally makes it possible to adjust the F rate, the elastic moduli in compression and the penetration distance. In particular:

[0234] - an increase in salt content generally tends to decrease the F rate and increase the compression moduli of elasticity and the penetration distance, and

[0235] - a decrease in the salt content generally tends to increase the F rate and decrease the compression moduli of elasticity and the penetration distance; ii) when an initiator is present, the molar ratio of initiator / crosslinkable compound capable of forming a hydrogel generally makes it possible to adjust the F rate, the compression moduli of elasticity and the penetration distance. In particular:

[0236] - an increase in such a molar ratio generally tends to increase the F rate and to decrease the elastic moduli in compression and the penetration distance, and - a decrease in such a molar ratio generally tends to decrease the F rate and to increase the elastic moduli in compression and the penetration distance; iii) the molar ratio of crosslinking agent / crosslinkable compound capable of forming a hydrogel generally makes it possible to adjust the penetration force and the F rate. In particular, an increase in such a molar ratio generally tends to increase these parameters, and a decrease in such a molar ratio tends to decrease these parameters.

[0237] Glazing

[0238] The glazing according to the invention comprises a first and a second glazed wall forming between them a first cavity, in which the first cavity comprises a hydrogel as defined above.

[0239] For the purposes of the present invention, a “glazed wall” means any structure comprising (or consisting of) at least one glass sheet or glazed device. “Glazed device” means a multi-layer glazed element of which at least one layer is a glass sheet. The glass sheet may be made of organic glass (e.g. polycarbonate) or mineral glass. It may be made of annealed glass or tempered glass. It may be made of soda-lime glass, borosilicate glass, or even glass-ceramic.

[0240] The glazed walls (or one of the glazed walls) may comprise (or consist of) a glazed device comprising at least one glass sheet which may be as described above. The glazed device is preferably a laminated glazing unit. By "laminated glazing" is meant at least two glass sheets bonded together by an interlayer film generally made of viscoelastic plastic material. The interlayer film may comprise one or more layers of a viscoelastic polymer such as poly(vinyl butyral) (PVB) or an ethylene-vinyl acetate copolymer (EVA), or ethylene copolymer, more preferably PVB.

[0241] Each glazed wall comprises two main faces opposite each other corresponding to the faces of the glazed wall having the largest surface areas. Advantageously, the glazed walls independently have a thickness (between their two main faces) greater than or equal to 1.6 mm, for example a thickness of 1.6 to 24 mm, preferably 2 to 15 mm, more preferably 3 to 10 mm, for example 4 or 8 mm. The glazed walls of the glazing according to the invention may all have the same thickness or have different thicknesses.

[0242] Preferably, all the glazed walls of the glazing have an identical height and width. The glazing according to the invention may have any possible shape, for example, a circular shape, an elliptical shape, a trapezoidal shape or a quadrilateral shape, in particular a rectangular shape. Preferably, the glazing has a rectangular shape.

[0243] The glazing according to the invention may comprise one or more additional glazed walls and one or more additional cavities. In one embodiment, the glazing according to the invention comprises a third glazed wall and a second cavity formed between the third glazed wall and one of the first and second glazed walls. In such an embodiment, the second cavity advantageously comprises a second hydrogel, which is typically a hydrogel as defined in the present application.

[0244] One (or more) of the glass walls may be tinted throughout, or over all or part of its surface. One (or more) of the glass walls may be wholly or partly covered with an opaque coating, for example, paint and / or enamel. In embodiments, only one of the glass walls of the glazing is covered with an opaque coating.

[0245] We prefer that each glass wall be transparent.

[0246] It is preferred that each glass wall be non-diffusing.

[0247] The glazing according to the invention is advantageously transparent.

[0248] The glazing according to the invention is advantageously non-diffusing.

[0249] In the CIELAB color space, the glazing according to the invention advantageously has a b* value of less than 3, preferably less than 2, or even less than 1.5, for example between 0 and 1.

[0250] In the CIELAB color space, the glazing according to the invention advantageously has an a* value less than 2, preferably less than 1, or even less than 0, for example between -5 and -0.5.

[0251] In the CIELAB color space, the glazing according to the invention advantageously has an L* value greater than 80, preferably greater than 90, or even greater than 95.

[0252] The glazing typically includes one or more spacer devices. A "spacer device" means any device for setting the spacing distance between the glass walls of the glazing in which it is intended to be placed. Each spacer device may be arranged along a different edge of the glazing. For example, for a glazing having four edges, the device may include four spacer devices arranged along the four edges.

[0253] More particularly, each device is typically positioned in the first cavity formed between the first and second glazed walls of the glazing, more particularly in a peripheral zone of the first cavity of the glazing. By "peripheral zone of the cavity", we mean an area of ​​the cavity adjacent to the edges of the glazed walls and preferably of width (i.e. in a direction orthogonal to the edge of the glazed walls, in the plane of the glazed walls) less than or equal to 100 mm, more preferably less than or equal to 50 mm, more preferably less than or equal to 20 mm, more preferably less than or equal to 10 mm, more preferably less than or equal to 7 mm. Generally, each spacing device is parallel to an edge of the glazed walls.

[0254] Where the glazing comprises one or more additional glazed walls and one or more additional cavities, typically spacers are also positioned in the additional cavities, particularly in a peripheral area of ​​the additional cavities.

[0255] The spacers may be disjointed (all or some of them) or may be joined to each other (all or some of them), preferably at their ends. Preferably, all the spacers of the spacer may be joined to form a frame, as a single piece (the spacers originating, for example, from a single spacer bent in one or more places, for example to form the corners of the frame) or may be joined together by any suitable means, for example by means of staples, glue, clips and / or by interlocking or welding.

[0256] One (or more) sealing gaskets may also be present, preferably arranged on the external face of the spacer device. More preferably, the sealing gasket extends from this external face to the edge of the glass walls. This sealing gasket may be made with a sealant (called a "sealing sealant") based on polyurethane, polysulfide and / or silicone.

[0257] The material of the spacer(s) may be a plastic or metallic material. Preferably, the spacer(s) are free of desiccant.

[0258] One or more of the spacers advantageously comprise an opening. The thickness of the first cavity between the first and second glazed walls, corresponding to the distance between the first and second glazed walls, is advantageously 1 to 100 mm, for example 8 to 12 mm, 14 to 20 mm, 15 to 30 mm or 20 to 40 mm. Typically, when there are several cavities, each of the cavities independently has a thickness of 1 to 100 mm, for example 8 to 12 mm, 14 to 20 mm, 15 to 30 mm or 20 to 40 mm.

[0259] In general, the hydrogel occupies at least 90%, for example at least 95%, preferably at least 98%, or even at least 99.9% of the volume of the cavity formed between the first and second glass walls.

[0260] The glazing according to the invention can be used in any application using glazing. In particular, the glazing according to the invention can be building glazing. The glazing can be intended to provide the interface between the exterior and the interior of the building, and can, for example, be facade glazing, window glazing or door glazing. Alternatively, the glazing can be intended to be placed inside the building. The glazing according to the invention can also be used in the field of transport, for example as train or boat glazing.

[0261] The present invention also relates to a method for manufacturing a glazing as defined in the present application, comprising: i) providing a first and a second glazed wall, ii) arranging the first and second glazed walls so as to form a first cavity between them, iii) introducing a gelling composition into the first cavity, and iv) polymerizing the gelling composition, to form a hydrogel, said hydrogel being as defined in the present application.

[0262] It is understood that the various aspects, particular modes, preferred modes, described in the present application for the glazing according to the invention also apply to the method according to the invention.

[0263] The following examples illustrate the present invention, in a non-limiting manner.

[0264] EXAMPLES Transparency measures

[0265] Transparency measurements were carried out with a colorimeter to determine the values ​​of the CIELAB L*a*b* color space and thus assign a color / transparency value to the samples.

[0266] For this measurement, according to the EN410 standard, the illuminant is D65, the angle is 10, and the reference observer is CIE 1976.

[0267] Frost penetration tests at break

[0268] Gel penetration tests were performed using a Zwick Roell tensile tester in compression mode using a 13 cm long punch with a 1.5 cm spherical tip as the upper grip and a flat jaw as the lower plate to hold the vial containing the sample. The load cell used was 100 N. The test began with the gel being brought into contact with the punch, at an angle of 90°C between the punch and the gel surface. The punch penetrated the gel until rupture, at a speed of 15 mm / min. This test allows the determination of the penetration force as well as the penetration distance to rupture.

[0269] The tests were carried out on a cylindrical hydrogel with a height of 10 cm and a diameter of 4.5 cm. Penetration was carried out in the direction of the sample height.

[0270] Compression tests

[0271] Compression tests were performed using a Zwick Roell tensile tester with a 100 N load cell and using 2 flat jaws (bottom and top). Once the upper plate was in contact with the sample, it was compressed at a speed of 3 mm / min until rupture. This test allows the determination of the compressive moduli of elasticity, in particular the compressive moduli of elasticity from 0 to 2 mm of strain (initial compressive modulus of elasticity El), and from 4 to 6 mm of strain (compressive modulus of elasticity E2). The strain was applied in the direction of the sample thickness.

[0272] The tested hydrogels had a rectangular parallelepiped geometry of 35 x 35 mm with a thickness of 17 mm.

[0273] Rate F: heating to 400°C

[0274] The hydrogels were heated in an oven at 400°C, and the mass of the hydrogel was measured by weighing every 15 minutes.

[0275] The hydrogels tested were in the form of a parallelepiped with dimensions of 25 x 35 x 17 mm.

[0276] Foaming score The test was carried out in an oven at 400°C. The polymer mass loss was monitored every 15 min, as well as the change in appearance of the hydrogels over time. The total heat treatment time was 60 min. The foaming score was determined by imaging.

[0277] The tested hydrogels had a geometry of 35 x 25 x 17 mm.

[0278] The sample was assigned a score on a scale of 1 to 5, based on the volume change, where a score of 1 corresponds to no foaming (zero volume change) and a score of 5 corresponds to strong foaming (high volume change). Optimal foaming is scored as 2.

[0279] Figure 1 shows examples of hydrogels with their foaming score.

[0280] Synthesis of hydrogels

[0281] Example 1 (invention): In a beaker, 1554 g of water and 480 g of NaCl were added. Once the NaCl was dissolved, 0.048 g of powdered NaOH was poured. When all the NaOH was dissolved, 270 g of a 47% methylolacrylamide solution and 96 g of MgCl z .6H z O were incorporated into the mixture. After solubilization, 1.32 g of TEA and 7.2 g of N,N'-methylenebisacrylamide (MBA) were added. The mixture was prepared under nitrogen and then degassed under vacuum before pouring it into the mold.

[0282] Comparative examples:

[0283] Example 2: In a beaker, 69 g of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) were dissolved in 98 g of water. Then, 13.3 g of solid NaOH was added, then, once dissolved and the beaker at room temperature, 23.4 g of the potassium salt of 3-sulfopropyl acrylate was added. Then, 241.16 g of MgCl z -6 H ZO, with 20 g of NaCl, 281 g of water and 3.5 g of IM NaOH solution and 1.85 g of polyethylene glycol diacrylate (PEGDA).

[0284] Example 3: Example 2 was repeated using 0.4 g of PEDGA.

[0285] Example 4: Example 2 was repeated using 1.2 g of PEDGA.

[0286] Example 5: Example 2 was repeated using 1.6 g of PEDGA.

[0287] Example 6: In a beaker were dissolved 75 g of 2-acrylamido-2-methylpropane sulfonic acid, 360 g of MgCl z -6 H Z 0.19 g of NaCl, 0.2 g of N,N'-methylenebisacrylamide and 13.2 g of methacrylamide in 478 g of water. 45 g of 32% NaOH and 10.4 g of 4% potassium persulfate solution were added. The gel was then placed in an oven for 24 hours at 45°C. Example 7: Example 6 was repeated using 1.0 g of MBA.

[0288] Results

[0289] [Table 1]

[0290] The hydrogel of Example 1 further exhibits a penetration force of 15 N and a penetration distance to break of 17.3 mm.

[0291] Table 1 shows that the hydrogel according to the invention, having an F rate of less than 50% at 15 min, and an F rate of less than 100% at 45 min, has an optimal foaming capacity, which allows controlled retention of water within the hydrogel when the latter is subjected to heat treatment. It also preserves good mechanical strength.

Claims

CLAIMS 1. Fire-resistant glazing comprising a first and a second glazed wall forming between them a first cavity, characterized in that the first cavity comprises a hydrogel having: - an F rate less than or equal to 50%, after heating the hydrogel to 400°C for t=15 minutes, and - an F rate less than or equal to 100%, after heating the hydrogel to 400°C for t=45 minutes, where the F rate is defined by the following equation: [Eq 4] F (%) = 100 x [(m0- m t ) / m a ] where: mo is the initial mass of the hydrogel, m t is the mass of the hydrogel after heating at 400°C for a time t, and m a is the initial mass of water in the hydrogel.

2. Glazing according to claim 1, characterized in that the hydrogel has a compressive modulus of elasticity E2 of 10 to 80 kPa, advantageously of 10 to 75 kPa, preferably of 10 to 50 kPa, or even of 10 to 40 kPa, very particularly of 10 to 25 kPa, better still of 10 to 20 kPa, the compressive modulus of elasticity E2 being determined for a deformation of 4 to 6 mm on a sample of 35x35x17 mm.

3. Glazing according to claim 1 or 2, characterized in that the hydrogel has an initial compressive modulus of elasticity El of 3 to 30 kPa, preferably 3 to 25 kPa, better still 3 to 20 kPa, or even 3 to 15 kPa, or even 4 to 10 kPa, the initial compressive modulus of elasticity El being determined for a deformation of 0 to 2 mm on a sample of 35x35x17 mm.

4. Glazing according to any one of claims 1 to 3, characterized in that the hydrogel has a penetration force of 5 to 20 N, preferably 6 to 15 N, or even 6 to 12 N.

5. Glazing according to any one of claims 1 to 4, characterized in that the penetration distance at break of the hydrogel is 10 to 35 mm, preferably 15 to 30 mm.

6. Glazing according to any one of claims 1 to 5, characterized in that the glazing is transparent.

7. Glazing according to any one of claims 1 to 6, characterized in that the hydrogel has an a* value of less than 2, preferably less than 1, or even less than 0, for example between -5 and -0.5, in the CIELAB color space.

8. Glazing according to any one of claims 1 to 1, characterized in that the first cavity has a thickness of 1 to 100 mm, for example 8 to 12 mm, 14 to 20 mm, 15 to 30 mm or even 20 to 40 mm.

9. Glazing according to any one of claims 1 to 8, characterized in that the glazing is building glazing, such as facade, window or door glazing, or interior glazing.

10. Glazing according to any one of claims 1 to 9, characterized in that the hydrogel is formed from a gelling composition comprising, relative to the total weight of the composition: - 4 to 40% by weight of one or more crosslinkable compounds capable of forming a hydrogel, - 10 to 60% by weight of one or more salts, - 0.001 to 1% by weight of one or more crosslinking agents, - 40 to 90% by weight of an aqueous vehicle, and - optionally 0.001 to 0.1% by weight of one or more polymerization initiators and / or catalysts.

11. Glazing according to claim 10, characterized in that the crosslinkable compound(s) capable of forming a hydrogel is (are): i) a vinyl monomer carrying a carboxylic acid, ester or amide group, ii) a vinyl monomer carrying a carboxylic acid, ester or amide group, where said group is substituted by an alkylsulfonic acid group, an ester or a salt thereof, or - a mixture of these.

12. Glazing according to claim 10 or 11, characterized in that the gelling composition is free of polyethylene glycol diacrylate.

13. A method of manufacturing a glazing unit as defined in any one of claims 1 to 12, comprising: i) providing a first and a second glazed wall, ii) arranging the first and second glazed walls so as to form a first cavity between them, iii) introducing a gelling composition into the first cavity, and iv) polymerizing the gelling composition, to form a hydrogel.

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