Passive fire protection device comprising silicone foam

Abstract

The invention relates to a passive fire protection device, said device comprising at least one strip of silicone foam having a density of less than 0.20 g / cm³. This passive fire protection device is particularly useful for protecting equipment critical to the safety and security of an installation, such as cables, cable trays, ventilation and smoke extraction ducts, penetrations, joints, and enclosures. Abbreviation: No figures

Description

Title of the invention: Passive fire protection device comprising a silicone foam technical field

[0001] The present invention relates to the technical field of silicone foams, and more specifically to the use of silicone foam strips for passive fire protection of equipment, in particular: - cables and cable trays, ventilation and smoke extraction ducts; - penetrations (cables, steel, copper, stainless steel pipes, etc.), fire-resistant penetrations; - fire-resistant joints; - fireproof boxes protecting specific devices, including devices important for the safety and security of an installation, for example pumps, valves, sensors or actuators. Prior art

[0002] A cable tray is a device allowing the passage of one or more cables (generally electrical cables, computer cables and / or multimedia cables), or piping to facilitate the distribution of fluids (air, gas, etc.).

[0003] It is common to use fire-resistant coverings to protect cable trays. Passive fire protection covers are generally flexible devices with fire-resistant properties that can withstand temperatures up to 1300°C.

[0004] Examples include the following prior art documents:

[0005] - Patent application EP 0 612 540 A1 describes a flexible protective device having fire-resistant properties comprising a complex of fibrous and / or textile elements assembled by gluing.

[0006] - Patent application EP 2 072 087 A1 describes a mattress for fire protection comprising at least two fibrous sub-assemblies based on layers of mineral fiber wool separated by a mineral fiber fabric, at least one layer of refractory glue bonding the fibrous sub-assemblies together, and an envelope comprising a mineral fiber fabric impregnated with a fire-retardant silicone and enclosing all the fibrous sub-assemblies.

[0007] - Patent application EP 2 694 164 Al also describes a coating of fire protection comprising several superimposed fibrous layers and a layer of refractory glue placed between two fibrous layers.

[0008] In these various documents, the fire-resistant material contains at least one fibrous element. However, in the event of rupture, the fibrous products can generate residues. These materials can clog safety devices in installations, such as cooling circuits. Therefore, the presence of fibrous elements is contraindicated in high-risk installations, such as nuclear power plants.

[0009] Patent application EP 3 799 935 A2 proposed a solution to this specific problem: it describes a fire-resistant blanket comprising a first layer made of a heat-resistant fabric, in particular a glass fabric or a meta-aramid fiber fabric, and a second layer made of an intumescent material. Furthermore, this document describes a fire protection device using one or more of these blankets laid in a staggered pattern. According to this document, the fire-resistant blankets have the advantage of being lightweight and flexible and do not risk projecting fibers that could clog filters in the event of damage to the cable tray protections due to steam or other impacts. However, assembling these blankets is difficult: the blankets must be arranged in such a way as to provide expansion zones for the intumescent material in the event of a fire.

[0010] In this context, the present invention aims to provide a new passive fire protection device that is flexible, lightweight, and easily handled, with fire-resistant properties and good mechanical strength up to 1300°C. This new device is advantageously free of fibrous elements. It provides protection for safety-critical equipment in high-risk facilities, such as nuclear power plants. Furthermore, this new device is removable, cleanable, and decontaminable.

[0011] More generally, the present invention aims to provide a new passive fire protection device for equipment, in particular equipment important for the safety and security of an installation, for example cables, cable trays, ventilation and smoke extraction ducts, crossings, joints and boxes. Summary of the invention

[0012] The present invention therefore relates to a passive fire protection device, said device comprising at least one strip comprising a silicone foam having a density of less than 0.20 g / cm3.

[0013] The invention also relates to a method for preparing a passive fire protection device, said method comprising (A) the preparation of a strip comprising a silicone foam, said preparation comprising the steps of: - prepare a silicone composition capable of forming a foam by releasing a gas; - deposit said composition in a mold; - close the mold; and - allow the said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

[0014] Furthermore, the invention relates to the use of said passive fire protection device for equipment, in particular equipment important for the safety and security of an installation, for example cables, cable trays, ventilation and smoke extraction ducts, crossings, joints and boxes, and especially for wrapping cable trays, preferably in high-risk installations, such as nuclear power plants. Brief description of the figures

[0015] [Fig.1] represents an embodiment of a mold according to the invention.

[0016] [Fig.2] represents an embodiment of a strip before (2A) and after (2B) its demolding according to the present invention.

[0017] [Fig.3] represents an embodiment of a passive fire protection device according to the invention.

[0018] [Fig.4] is a photograph of a strip obtained according to the example according to the invention. Detailed description of the invention

[0019] Unless otherwise indicated, all the viscosities of silicone oils referred to in this presentation correspond to a dynamic viscosity quantity at 25°C called "Newtonian", that is to say the dynamic viscosity which is measured, in a manner known per se, with a Brookfield viscometer at a shear rate gradient sufficiently low so that the measured viscosity is independent of the rate gradient.

[0020] The present invention therefore relates to a passive fire protection device, said device comprising at least one strip comprising a silicone foam having a density of less than 0.20 g / cm3.

[0021] A strip can be defined as a shape whose thickness is significantly less than its length and width. A strip can typically be: - between 50 cm and 5 m long; - between 10 cm and 50 cm wide; - between 1 cm and 5 cm thick.

[0022] The expression "silicone foam" or "silicone foam" refers to a composition of organopolysiloxanes in the form of a foam.

[0023] According to a preferred embodiment, the silicone foam according to the present invention is obtained from a polyaddition crosslinking silicone composition and whose foaming reaction generates hydrogen.

[0024] Without being bound by any particular theory, the foaming phenomenon can be described as follows: A polyaddition crosslinking composition is used, comprising an organopolysiloxane bearing silicon-bonded vinyl groups, an organopolysiloxane containing silicon-bonded hydrogen atoms, and a porogen comprising a hydroxyl group. The hydroxyl group of the porogen reacts with the hydride-membered organopolysiloxane, producing hydrogen gas and silanol. The silanol then reacts with the hydride-membered organopolysiloxane via a hydrogen condensation reaction, generating a second molecule of hydrogen gas, while another polydiorganosiloxane bearing silicon-bonded vinyl groups simultaneously reacts via an addition reaction with another hydride-membered polydiorganosiloxane, thus contributing to the formation of the silicone foam network.

[0025] Although the polyaddition crosslinking composition as described above is the preferred embodiment of the silicone foam according to the present invention, other silicone compositions capable of forming a foam are entirely conceivable, provided that the composition releases a gas enabling the foaming phenomenon. In one embodiment, the silicone composition contains a porous agent that expands the material under the action of heat by decomposition with the release of gas, particularly in the case of azo derivatives, for example azodicarbonamide, which releases nitrogen, carbon dioxide, and ammonia. In another embodiment, the silicone composition contains a porous agent that expands the material under the action of heat by phase change, typically liquid to gas, particularly in the case of low-boiling-point solvents.

[0026] According to a preferred embodiment, the silicone foam is obtained from a silicone composition comprising: - at least one organopolysiloxane A having, per molecule, at least two C2-Ci2 alkenyl groups linked to silicon, - at least one organopolysiloxane B having, per molecule, at least two SiH motifs, - a catalytically effective amount of at least one hydrosilylation catalyst C, and - at least one porogenous agent D comprising a hydroxyl group.

[0027] The organopolysiloxane A having, per molecule, at least two alkenyl groups, in C2-Ci2 bonded to silicon, may preferably be a linear organopolysiloxane formed: - of at least two siloxyl motifs with the following formula: YaR1bSiO(4_a.b) / 2 in which Y represents a C2-Ci2 alkenyl group, preferably a vinyl group; R1 represents a monovalent hydrocarbon group having from 1 to 12 carbon atoms, preferably selected from alkyl groups having from 1 to 8 carbon atoms such as methyl, ethyl, propyl groups, cycloalkyl groups having from 3 to 8 carbon atoms, and aryl groups having from 6 to 12 carbon atoms; a = 1 or 2, b = 0, 1, or 2, and the sum a+b = 2 or 3, and - possibly with patterns of the following formula: R1cSiO(4_c) / 2 in which R1 has the same meaning as above and c = 2 or 3.

[0028] H is understood in the above formulas that, if several groups R1 are present, they may be identical or different from each other.

[0029] In the following section concerning the description of organopolysiloxane A, the following nomenclature has been used to represent the siloxyl motifs: M: siloxyl motif R*3SiOi / 2, MV1: siloxyl motif chosen from YR*2SiOi / 2 and Y2R*SiOi / 2, D: siloxyl motif R^SiO^, DV1: siloxyl motif chosen from Y2SiO2 / 2 and YR'SiO^, T: siloxyl motif R'SiCL^, Q: Siloxyl motif SiO4 / 2, with Y and R1 as defined previously.

[0030] Examples of terminal motifs M and MV1 include trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy groups.

[0031] Examples of D and DV1 motifs include dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy groups.

[0032] As examples of T motifs, the methylsiloxy group can be cited.

[0033] The organopolysiloxane A having, per molecule, at least two alkenyl groups, in C2-Ci2 linked to silicon, can preferably be a linear organopolysiloxane essentially made up of siloxyl motifs D and / or DV1, and terminal siloxyl motifs M and / or MV1.

[0034] Examples of linear organopolysiloxanes that could be an organopolysiloxane A according to the invention are: - a poly(dimethylsiloxane) with dimethylvinylsilyl ends; - a poly(dimethylsiloxane-co-methylphenylsiloxane) with dimethylvinylsilyl ends; - a poly(dimethylsiloxane-co-methylvinylsiloxane) with dimethylvinylsilyl ends; and - a poly(dimethylsiloxane-co-methylvinylsiloxane) with trimethyl-silyl ends.

[0035] Preferably, the organopolysiloxane A contains terminal dimethylvinylsilyl motifs and even more preferably the organopolysiloxane A is a poly(dimethylsiloxane) with dimethylvinylsilyl ends.

[0036] Preferably, organopolysiloxane A is an oil with a dynamic viscosity between 100 mPa.s and 100,000 mPa.s, preferably between 100 mPa.s and 80,000 mPa.s, and more preferably between 1,000 mPa.s and 50,000 mPa.s.

[0037] Preferably, organopolysiloxane A has a mass content of alkenyl motif between 0.001% and 30%, preferably between 0.01% and 10%, preferably between 0.02% and 5%.

[0038] The silicone composition preferably comprises 40% to 80% by weight of organopolysiloxane A, even more preferably 50% to 70% by weight of organopolysiloxane A. According to one embodiment, the silicone composition does not comprise branched organopolysiloxanes or resins comprising C2-Ci2 alkenyl motifs.

[0039] Organopolysiloxane B is an organopolysiloxane having, per molecule, at least two SiH motifs. It is therefore an organohydrogenopolysiloxane compound. Preferably, compound B comprises at least three SiH motifs.

[0040] The organopolysiloxane B may advantageously be an organopolysiloxane comprising at least two, preferably at least three, siloxyl motifs of the following formula: HdR2eSiO(4-de) / 2 in which R2 represents a monovalent radical having from 1 to 12 carbon atoms, d = 1 or 2, e = 0, 1 or 2 and d+e = 1, 2 or 3; and possibly other patterns of the following formula: R2fSiO(4_f) / 2 in which R2 has the same meaning as above, and f = 0, 1, 2, or 3.

[0041] It is understood that, if several R2 groups are present in the above formulas, they may be identical or different from each other.

[0042] Preferably, R2 may represent a monovalent radical selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having 3 to 8 carbon atoms, and aryl groups having 6 to 12 carbon atoms. R2 may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl, and phenyl.

[0043] The symbol d is preferably equal to 1.

[0044] In the following section concerning the description of organopolysiloxane B, the following nomenclature has been used to represent the siloxyl motifs: M: siloxyl motif R23SiOi / 2, M': siloxyl unit R22HSiOi / 2, D: siloxyl motif R22SiO2 / 2, D': siloxyl motif R2HSiO2 / 2, T: siloxyl motif R2SiO3 / 2, Q: Siloxyl motif SiO4 / 2, with R2 as defined previously.

[0045] Organopolysiloxane B may have a linear, branched, or cyclic structure. The degree of polymerization is preferably greater than or equal to 2. Generally, it is less than 5000. Preferably, the viscosity of organopolysiloxane B is between 1 mPa.s and 5000 mPa.s, more preferably between 1 mPa.s and 2000 mPa.s, and even more preferably between 5 mPa.s and 1000 mPa.s.

[0046] When it comes to linear polymers, these are essentially made up of D and / or D' siloxyl motifs, and terminal M and / or M' siloxyl motifs. When it comes to cyclic polymers, these are essentially made up of D and / or D' siloxyl motifs.

[0047] Examples of organohydrogen polysiloxanes that can be organopolysiloxanes B according to the invention are: - a poly(dimethylsiloxane) with hydrogenodimethylsilyl ends; - a poly(dimethylsiloxane-co-methylhydrogenosiloxane) with trimethylsilyl ends; - a poly(dimethylsiloxane-co-methylhydrogenosiloxane) with hydrogenodimethylsilyl ends; - a poly(methylhydrogenosiloxane) with trimethysilyl ends; and - a cyclic poly(methylhydrogenosiloxane).

[0048] When organopolysiloxane B has a branched structure, it is preferably chosen from the group consisting of silicone resins of the following formulas: - M'Q where the hydrogen atoms linked to silicon atoms are carried by the M groups; - MM'Q where hydrogen atoms bonded to silicon atoms are carried by part of the M motifs; - MD'Q where hydrogen atoms bonded to silicon atoms are carried by the D groups; - MDD'Q where hydrogen atoms bonded to silicon atoms are carried by a part of the D groups; - MM'TQ where hydrogen atoms bonded to silicon atoms are carried by part of the M motifs; - MM'DD'Q where hydrogen atoms bonded to silicon atoms are carried by part of the M and D motifs; - and their mixtures.

[0049] Preferably, the organopolysiloxane B has a mass content of hydrogenosilyl Si-H functions between 0.2% and 91% more preferably between 3% and 80% and even more preferably between 15% and 70%.

[0050] Advantageously, the molar ratio of the hydrogenosilyl Si-H functions of the organopolysiloxanes B to the alkene functions of the organopolysiloxanes A is between 5 and 100, preferably between 10 and 90, more preferably between 15 and 65, and even more preferably between 20 and 55.

[0051] The silicone composition according to the invention preferably comprises 1% to 20% by weight, and more preferably 3% to 15% by weight, of organopolysiloxane B.

[0052] The hydrosilylation catalyst C may be selected from platinum and rhodium compounds, but also from silicon compounds such as those described in patent applications WO 2015 / 004396 and WO 2015 / 004397, germanium compounds such as those described in patent applications WO 20160 / 75414, or nickel, cobalt, or iron complexes such as those described in patent applications WO 2016 / 071651, WO 2016 / 071652, and WO 2016 / 071654. The catalyst C is preferably a compound derived from at least one metal belonging to the platinum group. These catalysts are well known. In particular, one can use the complexes of platinum and an organic product described in US patents 3,159,601, US 3,159,602, US 3,220,972 and European patents EP 0.057.459, EP 0.188.978 and EP 0.190.530, the complexes of platinum and vinylized organosiloxanes described in US patents 3,419,593, US 3,715,334, US 3,377,432 and US 3,814,730.

[0053] Preferably, catalyst C is a platinum-derived compound. In this case, the weight quantity of catalyst C, calculated in terms of platinum-metal weight, is generally between 2 ppm and 400 ppm by mass, preferably between 5 ppm and 200 ppm, based on the total weight of the silicone composition.

[0054] Preferably, the catalyst C is a Karstedt platinum.

[0055] The porogen agent D comprising a hydroxyl group may be chosen from the group consisting of water, polyols, monofunctional alcohols, organosilanes containing at least one silanol group, organosiloxanes containing at least one silanol group, and mixtures thereof.

[0056] According to a preferred embodiment, the porogenic agent D is water. The water can be added directly to the silicone composition. Alternatively, the water can be introduced in the form of an aqueous emulsion, for example, a direct oil-in-water silicone emulsion or a reverse water-in-oil silicone emulsion comprising a continuous silicone oil phase, an aqueous phase, and a stabilizer. According to a In this embodiment, water is introduced via a silicone oil emulsion with a water content of approximately 60% by weight. When water is introduced into the silicone composition via an emulsion, the dispersion of water within the silicone composition and its storage stability are improved.

[0057] According to another embodiment, the porogen D is a polyol. Preferably, it is an organic polyol having from 3 to 12 carbon atoms and comprising at least 2 hydroxyl groups per molecule. The polyol may be linear or branched, and it may optionally comprise one or more aromatic rings. Examples include saturated polyhydric alcohols having at least 2 hydroxyl groups per molecule, such as those described in US 4,871,781. Examples of polyols that can be used as a porogen according to the invention are: - diols, for example 1,2-ethanediol, 2,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol; - triols, for example 1,2,3-propanetriol and 2,2-bis-hydroxymethyl-butanol; - tetrititols, for example erythritol and pentaerythritol; - pentitols, for example arabitol, xylitol, and methylpentitol; - hexitols, for example mannitol and sorbitol; and - cycloaliphatic polyols, for example cyclohexanediols, cyclohexane triols, and inositol.

[0058] According to another embodiment, the porogen D is a monofunctional alcohol. Preferably, it is an organic alcohol having from 1 to 12 carbon atoms and comprising a single hydroxyl group per molecule. The alcohol may be linear or branched, and it may optionally comprise one or more aromatic rings. Examples of monofunctional alcohols that can be used as a porogen according to the invention are methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, n-octanol, benzyl alcohol, and mixtures thereof.

[0059] According to yet another embodiment, the porogen D is an organosilane containing one or more silanol groups. These compounds can, for example, be represented by the following formula (1) or formula (2): (1) (R3)3SiOH (2) (R3)2Si(OH)2 in which R3 represents a monovalent radical chosen from the group consisting of alkyl groups having 1 to 8 carbon atoms, possibly substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having 3 to 10 carbon atoms and aryl groups having 6 to 12 carbon atoms. It is understood that, if several R3 groups are present in the above formulas, they may be identical or different from each other.

[0060] Examples of organosilanes containing one or more silanol groups that can be used as a porogenic agent according to the invention are (CH3)3SiOH, (C6H5)SiOH, (CH3)(C6H5)2SiOH and (C6H5)2Si(OH)2.

[0061] According to yet another embodiment, the porogen D is an organosiloxane containing one or more silanol groups. Preferably, it may be an organopolysiloxane compound formed by: - of at least one siloxyl motif of the following formula: R3g(OH)hSiO(4 gh) / 2 in which R3 has the same meaning as above; g = 0, 1 or 2, h = 1 or 2, and the sum g+h = 1, 2 or 3, and - possibly with patterns of the following formula: R3iSiO(44) / 2 in which R3 has the same meaning as above and i = 0, 1, 2 or 3.

[0062] The silicone composition may further comprise other compounds, in particular: - at least one mineral filler, in particular silica, quartz, or a mixture thereof; - at least one additive for thermal resistance and / or fire resistance; - at least one diorganopolysiloxane gum; - a diorganopolysiloxane oil blocked at each end of its chain by a triorganosiloxy motif whose organic radicals linked to the silicon atoms are chosen from alkyl radicals having 1 to 8 carbon atoms; - a crosslinking inhibitor; - a coloring base; - optionally other charges.

[0063] According to a preferred embodiment, the silicone composition comprises a mineral filler, which is preferably a combustion silica or a precipitation silica. The silica-type mineral fillers preferably have a specific surface area, measured according to BET methods, of at least 50 m² / g, in particular between 50 m² / g and 400 m² / g, preferably greater than 70 m² / g, an average primary particle size of less than 0.1 pm (micrometer), and an apparent density of less than 200 g / liter. Most preferably, the mineral filler is a combustion silica with a specific surface area between 100 m² / g and 300 m² / g.

[0064] Mineral fillers of the silica type, preferably hydrophilic, can be incorporated as such into the silicone composition or optionally treated with a compatibilizing agent. According to one embodiment, these silicas can optionally be treated with one or more organosilicon compounds, for example organosilane or organosilazane, commonly used for this purpose. Among These compounds include methylpolysiloxanes such as hexamethyldisiloxane and octamethylcyclotetrasiloxane; methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, and tetramethyldivinyldisilazane; chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, and dimethylvinylchlorosilane; and alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, and trimethylmethoxysilane. These compounds can be used alone or in mixtures (see French patents FR 1 126 884, FR 1 136 885, FR 1 236 505 and English patent GB 1 024 234). In a preferred embodiment, the silica is treated during mixing with all or part of the organopolysiloxane A by an in-situ process. In an advantageous embodiment, the silica is treated with one or more hexaorganodisilazanes.Even more preferentially, silica is treated with hexamethyldisilazane alone or in a mixture with divinyltetramethyldisilazane.

[0065] Silica can optionally be pre-dispersed in a silicone oil to obtain a suspension. A suspension of treated combustion silica, in particular with hexamethyldisilazane, in a polyorganosiloxane oil, especially a vinylized one, is preferred.

[0066] Alternatively or in addition, the silicone composition according to the invention may also contain at least one other mineral filler, which is quartz. Preferably, ground natural quartz with an average particle size of less than 10 microns is used. The quartz may optionally be treated to improve its compatibility with organopolysiloxanes.

[0067] According to a preferred embodiment, the silicone composition contains a mixture of silica and quartz, with a mass ratio between quartz and silica preferably between 0.5 and 4, more preferably between 1 and 3.6, even more preferably between 1.5 and 3.2, and even more advantageously between 1.5 and 2.8.

[0068] Other mineral fillers may be considered, in particular packing fillers, such as for example diatomaceous earth, calcium carbonate and / or kaolin.

[0069] The silicone composition may optionally include at least one heat-resistant and / or fire-resistant additive. These heat-resistant and / or fire-resistant additives are well known to those skilled in the art. Advantageously, they may be chosen from the group consisting of: salts, oxides, and hydroxides of metals such as iron, titanium, aluminum, nickel, and copper; salts, hydroxides, and oxides of rare earth elements such as cerium and lanthanum; organophosphate compounds; platinum derivatives; carbon black; and calcium, aluminum, and / or potassium silicates such as, for example, mica and wollastonite. Hydrated mineral fillers, oxides, or carbonates may also be mentioned. of calcium, magnesium, or aluminum, such as magnesium hydroxide Mg(OH)2, aluminum hydroxide Al1(OH)3, hydromagnesite with the molecular formula Mg5(CO3)4(OH)2.4H2O, and calcium hydroxide. In another embodiment, hollow glass microspheres may be added to the silicone composition.

[0070] The silicone composition may optionally include at least one diorganopolysiloxane gum. Diorganopolysiloxane gums are linear polymers, of high molecular weight with a viscosity greater than 1000 Pa.s at 25°C, preferably greater than 2000 Pa.s, and whose diorganopolysiloxane chain is essentially made up of R2SiO2 / 2 motifs and blocked at each end by R3SiOi / 2 motifs, the R radical representing an alkyl radical having from 1 to 8 carbon atoms or an alkenyl radical having from 2 to 6 carbon atoms. The presence, along the diorganopolysiloxane chain, of small amounts of motifs other than R2SiO2 / 2, for example RSiO3 / 2 and / or SiO4 / 2 motifs, is not excluded, however, in a proportion of up to 2% relative to the number of R2SiO2 / 2 motifs. Preferably, diorganopolysiloxane gums comprise at least two C2-Ci2 alkenyl groups linked to silicon.Advantageously, diorganopolysiloxane gum has a vinyl motif mass content greater than 0.3%, preferably greater than 0.5%, more preferably between 0.5% and 6%, even more preferably between 0.5% and 4%, and even more preferably between 1% and 3.5%.

[0071] When the silicone composition includes a crosslinking inhibitor (or slower of the addition reaction), this may be chosen from the following compounds: an organopolysiloxane, advantageously cyclic, and substituted by at least one alkenyl, tetramethylvinyltetrasiloxane being particularly preferred, pyridine, organic phosphines and phosphites, unsaturated amides, alkylated maleates, and acetylenic alcohols, for example 1-ethynyl-1-cyclohexanol, methyl-3-dodecyne-1-ol-3, trimethyl-3,7,11-dodecyne-1-ol-3, diphenyl-1,1-propyne-2-ol-1, ethyl-3-ethyl-6-nonyne-1-ol-3 and methyl-3-pentadecyne-1-ol-3.

[0072] According to one embodiment, the silicone composition comprises (by weight relative to the total weight of the silicone composition): a. 40% to 80% by weight of at least one organopolysiloxane A having, per molecule, at least two C2-C[2] alkenyl groups linked to silicon, b. 1% to 20% of at least one organopolysiloxane B having, per molecule, at least two SiH motifs and preferably at least three SiH motifs, c. 2 ppm to 400 ppm by mass of a hydrosilylation catalyst C selected from platinum compounds (quantity calculated by weight of platinum-metal), and d. 0.3% to 2.5% by weight of a porogen D, e. at least 3% by weight of a combustion silica with a specific surface area between 100 m² / g and 300 m² / g, f. at least 6% by weight of at least one mineral filler which is crushed quartz, and g. from 0.4% to 5% by weight of at least one heat resistance and / or fire resistance additive.

[0073] According to another embodiment, the silicone composition comprises (by weight relative to the total weight of the silicone composition): a. 40% to 80% by weight of at least one organopolysiloxane A having, per molecule, at least two C2-Ci2 alkenyl groups linked to silicon, b. 1% to 20% by weight of at least one organopolysiloxane B having, per molecule, at least two SiH motifs and preferably at least three SiH motifs, c. 2 ppm to 400 ppm by weight of a hydrosilylation catalyst C selected from platinum compounds (quantity calculated by weight of platinum-metal), d. 0.3% to 2.5% by weight of a porogen D, e. 3% to 14% by weight of at least one mineral filler which is a combustion silica having a specific surface area between 100 m2 / g and 300 m2 / g, f. from 6% to 25% by weight of at least one mineral filler which is crushed quartz, g. from 0.4% to 5% by weight of at least one fire-resistant additive, h. from 0 to 3000 ppm by mass of a crosslinking inhibitor, and i. 0 to 4% by weight of a diorganopolysiloxane gum comprising at least two C2-Ci2 alkenyl groups linked to silicon.

[0074] Such a silicone composition allowing the production of a silicone foam is described for example in international patent application WO 2021 / 014058.

[0075] According to one embodiment, the silicone composition according to the invention can be prepared from a two-component (or multi-component) system characterized in that it is in two (or more) distinct parts intended to be mixed to form said silicone composition. In particular, in the case of preferred silicone compositions as described above, the silicone composition can be prepared from a two-component system characterized in that one of the parts comprises catalyst C and does not comprise organopolysiloxane B, while the other part comprises organopolysiloxane B and does not comprise catalyst C. Other multi-component systems may be provided to improve shelf life and / or optimize the viscosity of each of the components.For example, the silicone composition according to the invention can be prepared from a three-component system characterized in that it is in three distinct parts intended to be mixed to form said silicone composition.

[0076] The mixing of the parts of said two-component (or multi-component) system can typically take place in a mixer (mechanical paddle mixer, low-pressure dynamic mixer, or any other conventional stirring system) at a temperature close to ambient temperature, i.e., between 10°C and 40°C. An increase in the temperature of the silicone composition is sometimes observed during this mixing, depending on the type of mixer and the applied shear. If it is desired to accelerate the crosslinking or hardening of the silicone foam, the mixing can be carried out at a higher temperature, advantageously between 40°C and 70°C.

[0077] It is important to have a good quality of mixture to obtain a homogeneous silicone foam with good mechanical properties.

[0078] The silicone composition undergoes a crosslinking and / or hardening step to obtain the silicone foam. This step can vary in duration depending on the silicone composition and the temperature. Generally, a silicone foam with good properties is obtained after a few minutes or a few hours, depending on the temperature and the concentration of catalyst and inhibitor in the silicone composition.

[0079] The silicone foam according to the invention advantageously has a low density, preferably less than 0.20 g / mL, more preferably less than 0.17 g / mL. It is visually uniform with a homogeneous distribution of bubble sizes within the foam and does not contain large bubbles with a diameter greater than or equal to 2 mm.

[0080] In addition to its lightness, the silicone foam according to the invention advantageously exhibits good mechanical properties, excellent fire resistance and does not release toxic fumes when burned.

[0081] Thanks to these remarkable properties, silicone foam is flexible and easy to handle, and it can be advantageously used in a passive fire protection device.

[0082] The silicone foam according to the invention is preferably not an intumescent material. By "intumescent material" is meant a material capable of swelling under the effect of heat above a certain temperature.

[0083] The invention also relates to a method for manufacturing a passive fire protection device, said method comprising (A) the preparation of a strip comprising a silicone foam, said preparation comprising the steps of: - prepare a silicone composition capable of forming a foam by releasing a gas; - deposit said composition in a mold; - close the mold; and - allow the said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

[0084] The closed mold defines a hollow volume corresponding to the shape of the article to be molded. The mold can have a simple geometric shape, for example a parallelepiped shape as illustrated in [Fig. 1].

[0085] Preferably, the lower and upper walls of the mold define the largest surfaces of the molded article, while the side walls define the thickness of the molded article.

[0086] According to a first embodiment illustrated in [Fig. 1], the mold (1) consists of side walls (2) (four side walls are shown here), a lower wall (3), and an upper wall or lid (4). The lower wall (3) may optionally be provided with feet (5) to support the mold. The lid (4) is preferably removable, as illustrated in [Fig. 1]. During the preparation of the strip according to the present invention, the silicone composition can be deposited in the mold (1) (configuration IA), and then the lid (4) can be attached to the side walls, thus defining a closed hollow volume (configuration IB).

[0087] According to another embodiment (not shown), the mold may consist of two half-molds which, when assembled, define a closed hollow volume. During implementation of the process according to the present invention, the silicone composition can typically be injected into the closed hollow volume defined by the two assembled half-molds.

[0088] The walls of the mold can be made of a suitable material to ensure its mechanical strength, for example metal, typically steel or aluminum, rigid plastic, typically PET, polypropylene or polycarbonate, or a composite material.

[0089] According to a preferred embodiment, the mold includes a means for venting the gases generated during the crosslinking and / or hardening reaction of the silicone composition. In one embodiment, at least a portion of the walls of the mold according to the invention are made of two adjacent materials: a rigid, gas-permeable outer material, for example, a grid or a perforated plate, and a gas-permeable, liquid-impermeable inner material. Since the silicone composition is deposited into a mold in liquid form, it is necessary to provide a sealed internal material to contain the silicone composition in its liquid form before its crosslinking and / or hardening reaction. Preferably, said internal material is a flexible material, typically a fibrous material. This fibrous material may be of natural, artificial, and / or synthetic origin. It can be a woven, knitted, or non-woven fibrous material. When it is a woven or knitted fibrous support, that is, a fabric or knit, the yarns are advantageously based on thermoplastic polymer.As examples, suitable thermoplastic (co)polymers include: polyolefins, polyesters, alkylene polyoxides, polyoxyalkylenes, polyhaloalkylenes, poly(alkylene phthalate or terephthalate), poly(phenylene or phenylene), poly(phenylene oxide or sulfide), polyvinyl acetates, polyvinyl alcohols, polyvinyl halides, polyvinylidene halides, polyvinyl nitriles, polyamides, polyimides, polycarbonates, polysiloxanes, acrylic or methacrylic acid polymers, polyacrylates or methacrylates, natural polymers such as cellulose and its derivatives, synthetic polymers such as synthetic elastomers, or thermoplastic copolymers comprising at least one monomer identical to any of the monomers included in the aforementioned polymers. than mixtures and / or alloys of all these (co)polymers.When the fibrous material is a thermoplastic polymer, it is preferably polyester, such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), their copolymers and mixtures, or polyamide such as polyamide 6, polyamide 6.6, polyamide 4, polyamide 1.1, polyamide 1.2, polyamides 4-6, 6-10, 6-12, 6-36, 12-12, their copolymers and mixtures.

[0090] According to this preferred embodiment, at least the lower and upper walls of the mold are designed to allow the evacuation of gases generated during the crosslinking and / or hardening reaction of the silicone composition. Indeed, the lower and upper walls of the mold preferably define the largest surfaces of the molded strip. The side walls, which preferably define the thickness of the strip, have a smaller surface area.

[0091] After the silicone composition has been deposited, the mold can be closed, for example with a lid, as illustrated in Figure IB. The hollow volume defined by the closed mold should preferably remain fixed and resist the pressure created by the expansion of the foam. Fastening methods are known to those skilled in the art, for example, fasteners between the lid and the side walls, weights distributed on top of the lid, or a hydraulic system for keeping the lid closed.

[0092] The preparation of the strip finally includes a step of allowing the silicone composition to crosslink and / or harden to obtain the silicone foam. This step can vary in duration depending on the silicone composition and the temperature of the preceding deposition step. Generally, a silicone foam with good properties is obtained after a few minutes or a few hours, depending on the temperature and the concentration of catalyst and inhibitor in the silicone composition.

[0093] Advantageously, the entire silicone foam manufacturing process is conducted under air or nitrogen purging to avoid the risks associated with hydrogen release during the process. Furthermore, the silicone foam manufacturing process is preferably carried out at atmospheric pressure and ambient temperature, also to avoid the risks associated with hydrogen release. The ambient temperature is generally between 15°C and 40°C, typically around 25°C. In addition to safety reasons, implementing the process at atmospheric pressure and / or ambient temperature is a significant advantage in terms of technological simplification and implementation costs.

[0094] The process according to the present invention may optionally include an additional step of annealing the silicone foam. This optional annealing step may consist of a heat treatment lasting from one to several hours, preferably from one to four hours, at a temperature between 50°C and 200°C, preferably between 100°C and 150°C. It may, if necessary, improve the fire resistance and mechanical properties of the silicone foam. However, this step is not essential, and a process characterized by not including an additional annealing step is preferred.

[0095] After curing and / or hardening, and optionally annealing, a strip comprising a silicone foam is obtained and can be demolded. Advantageously, the material of the inner face of the mold, i.e., the material in contact with the silicone composition before its curing and / or hardening, and then in contact with the silicone foam after its curing and / or hardening, is chosen so as to facilitate demolding. For this purpose, the material is chosen from among those that adhere poorly or not at all to the silicone foam after its curing and / or hardening. Preferably, the material of the inner face of the mold is polyester. Alternatively, the material can be surface-treated to improve its non-adherence to the silicone foam, for example, with a fluorocarbon coating.

[0096] In addition to silicone foam, the passive fire protection device according to the present invention may advantageously include a textile backing. Textile backings usable in passive fire protection devices are known to those skilled in the art. Some examples are described in patent application EP 3 799 935 A2. The textile backing is preferably made of a heat-resistant material, for example, a glass fabric resistant to heat above 500°C or a meta-aramid fiber fabric. Glass fabric has the advantage of being inexpensive and offering good mechanical strength.

[0097] According to a preferred embodiment, the strip comprises a layer of silicone foam and a textile backing. In this context, step (A) of preparing the strip further comprises a step of placing a textile backing in the mold before depositing the silicone composition capable of forming a foam by releasing a gas. Step (A) can therefore be described as follows: - prepare a silicone composition capable of forming a foam by releasing a gas; - place a textile support in a mold; - place the said composition onto the said textile support; - close the mold; and - allow the said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

[0098] After curing and / or hardening, the resulting silicone foam adheres to the textile backing. The strip, comprising the silicone foam layer and the textile backing, can be demolded. Figure 2 shows a strip thus obtained before demolding (configuration 2A) and after demolding (configuration 2B). The strip (9) comprises a textile backing (7) and a silicone foam layer (8) that adheres to the textile backing (7). According to the illustrated embodiment, certain internal walls of the mold (1) and the lid (4) have been coated with a non-stick polyester fibrous material (6). During demolding, the lid (4) is removed, and the strip (9) can be easily extracted from the mold (1).

[0099] Advantageously, the tape may not include an adhesion primer between the silicone foam layer and the textile backing. Indeed, in the preparation process described above, the crosslinking and / or hardening reaction of the silicone foam takes place directly on the textile backing, and adhesion is thus obtained without an additional adhesion primer.

[0100] The method for manufacturing a passive fire protection device according to the present invention may further include (B) the assembly of one or more of said strips comprising a silicone foam.

[0101] The assembly can be carried out by a person skilled in the art using methods known in the technical field. A device may comprise several layers of strips joined together mechanically and / or chemically (bonding). For example, a strip comprising a silicone foam according to the invention can be wound upon itself. According to another example, several strips according to the invention can be stacked one on top of the other. Between each strip, an intermediate layer may optionally be positioned. This layer may optionally contain additives useful for passive fire protection and / or for mechanical reinforcement.

[0102] According to a first embodiment, the passive fire protection device according to the present invention may comprise, in addition to said strip(s) comprising a silicone foam, one or more layers containing additives useful for passive fire protection. Such additives are known to those skilled in the art in this technical field. By "additives useful for passive fire protection," we mean a compound that prevents or inhibits the spread of fire. Examples include metal hydroxides, which decompose and release water when heated. Among the most commonly used metal hydroxides for their passive fire protection properties are aluminum hydroxide (ATH) and magnesium hydroxide. The use of refractory particles is described, for example, in patent application EP 2 072 087 Al. These may include metal metasilicates, such as hydrated sodium metasilicate (Na2SiO3.nH2O). The use of such additives advantageously improves the fire resistance properties of the device and delays the temperature rise of the equipment it is intended to protect.

[0103] According to an alternative embodiment, the passive fire protection device according to the present invention does not contain additives capable of releasing alkaline water at high temperatures. In particular, the passive fire protection device according to the present invention does not contain metallic metasilicates. However, without wishing to be bound by this theory, the inventors believe that the silicone foam strip could be degraded at high temperatures by alkali metal hydroxides, which may be released by the metallic metasilicates.

[0104] Figure 3 illustrates an embodiment of a passive fire protection device (10) according to the invention, comprising three layers of tape arranged around a cable tray (11). The first layer of tape comprises a first layer of silicone foam (12) and a first textile backing (13). This first layer of tape is assembled with a second layer of tape, which comprises a second layer of silicone foam (14) and a second textile backing (15). This second layer of tape is assembled with a third layer of tape, which comprises a third layer of silicone foam (16) and a third textile backing (17). Between each layer of tape is an intermediate layer (18), which may contain additives useful for passive fire protection and / or mechanical reinforcement.However, according to an embodiment not shown, the passive fire protection device (10) according to the invention does not include an intermediate layer (18), the strip thicknesses then being directly adjacent to each other.

[0105] The first, second, and third strips, comprising a silicone foam layer and a textile backing layer, typically have a thickness between 1 cm and 3 cm. The intermediate layers typically have a thickness between 0 cm and 2 cm. The entire device after assembly can therefore have a thickness, according to this embodiment, between 3.2 cm and 13 cm.

[0106] Furthermore, the invention relates to the use of said passive fire protection device for equipment, in particular equipment important for the safety and security of an installation. Examples of such equipment include: - cables and cable trays, ventilation and smoke extraction ducts; - penetrations (cables, steel, copper, stainless steel pipes...), fire-resistant penetrations; - fireproof seals; - Fireproof boxes protecting specific devices, including devices important for the safety and security of an installation, for example pumps, valves, sensors or actuators.

[0107] In particular, the equipment in question can be selected from among the equipment important for the safety and security of an installation, especially a high-risk installation such as a nuclear power plant. According to a specific embodiment, the invention relates to the use of said passive fire protection device for wrapping cable trays, preferably in high-risk installations such as nuclear power plants.

[0108] Other details or advantages of the invention will become clearer in view of the examples given below, which are for illustrative purposes only. Examples

[0109] A silicone composition, capable of forming a foam and crosslinking by polyaddition, was prepared by mixing at room temperature the compounds described in Table 1 below:

[0110] [Tables 1] % by weight organopolysiloxane A Mixture of poly(dimethylsiloxane) with dimethylvinylsilyl ends, viscosity = 3500 to 20000 mPa.s 56.2 organopolysiloxane B Poly(methylhydrogenosiloxane) with trimethylsilyl ends, viscosity = 30 mPa.s 12 catalyst C Karstedt platinum catalyst 0.04 porogenic agent D Silicone emulsion containing about 59.5% by weight of water 1.16 silica Combustion silica having a specific surface area of ​​300 m2 / g treated with a mixture of hexamethyldisilazane and divinyltetramethyldisilazane 9.4 quartz Ground quartz of which half of the particles have a size less than or equal to 4 microns.15 organopolysiloxane gum Diorganopolysiloxane gum consisting essentially of dimethylsiloxane and methylvinylsiloxane motifs comprising 2.4% by weight of vinyl motifs 1.5 heat resistance and fire resistance additive Mixture of titanium dioxide, mica and cerium hydroxide 3.7 crosslinking inhibitor Solution containing 1% ethynylcyclohexanol in a polydimethylsiloxane oil blocked by (CH3)2(Vi)SiOi / 2 motifs, having a viscosity of 600 mPa.s at 25°C 1.0.

[0111] In a mold consisting of a perforated steel frame measuring 150x35x2 cm, a polyester fabric was placed at the bottom, followed by a layer of commercial fiberglass fabric approximately 2 mm thick. A lid, also made of a perforated steel plate, was covered with polyester fabric.

[0112] The silicone composition was deposited in the mold on the glass fabric, distributed homogeneously at the bottom of the mold using a scraper (liquid layer of approximately 3 mm), then the lid was fixed on the frame so as to form a closed mold.

[0113] After 45 minutes at 23°C, the resulting foam was demolded. As can be seen in [Fig. 4], the strip thus obtained comprises a glass fabric and a layer silicone foam. The foam density is approximately 0.15 g / mL. The silicone foam adheres perfectly to the fiberglass backing. The resulting strip is homogeneous, lightweight, and flexible. It can be easily handled and folded.

Claims

Demands

1. Passive fire protection device, said device comprising at least one strip (9) comprising a silicone foam (8) having a density of less than 0.20 g / cm3, said strip being between 50 cm and 5 m long, between 10 cm and 50 cm wide, and between 1 cm and 5 cm thick, said passive fire protection device comprising a textile backing (7), and the strip (9) not comprising an adhesion primer between the silicone foam layer (8) and the textile backing (7).

2. Passive fire protection device according to claim 1, wherein the silicone foam (8) is obtained from a polyaddition crosslinking silicone composition and whose foaming reaction generates hydrogen.

3. Passive fire protection device according to claim 1 or claim 2, wherein the silicone foam (8) is obtained from a silicone composition comprising: - at least one organopolysiloxane A having, per molecule, at least two silicon-linked C2-Ci2 alkenyl groups, - at least one organopolysiloxane B having, per molecule, at least two SiH motifs, - a catalytically effective amount of at least one hydrosilylation catalyst C, and - at least one porogen D comprising a hydroxyl group.

4. Passive fire protection device according to claim 3, wherein the silicone composition comprises (by weight relative to the total weight of the silicone composition): a. 40% to 80% by weight of at least one organopolysiloxane A having, per molecule, at least two silicon-bonded C2-Ci2 alkenyl groups, b. 1% to 20% of at least one organopolysiloxane B having, per molecule, at least two SiH motifs and preferably at least three SiH motifs, c. 2 ppm to 400 ppm by weight of a hydrosilylation catalyst C selected from platinum compounds (quantity calculated by weight of platinum-metal), and d. 0.3% to 2.5% by weight of a porogen D, e. at least 3% by weight of a combustion silica with a specific surface area between 100 m2 / g and 300 m2 / g, f. at least 6% by weight of at least one mineral filler which is crushed quartz, and g. from 0.4% to 5% by weight of at least one thermal resistance and / or fire resistance additive.

5. A method for preparing a passive fire protection device according to any one of claims 1 to 4, said method comprising (A) the preparation of a strip (9) comprising a silicone foam (8), said preparation comprising the steps of: - preparing a silicone composition capable of forming a foam by releasing a gas; - placing a textile support (7) in a mold; - depositing said composition on said textile support (7); - closing the mold (1); and - allowing said silicone composition to crosslink and / or harden to obtain the strip (9) comprising the silicone foam (8).

6. Method of preparing a passive fire protection device according to claim 5, wherein the mold (1) includes a means for venting the gases generated during the crosslinking and / or hardening reaction of the silicone composition.

7. Method of preparing a passive fire protection device according to claim 5 or claim 6 further comprising (B) the assembly of one or more of said strips comprising a silicone foam (12, 14, 16).

8. A method according to claim 5, wherein said passive fire protection device further comprises one or more layers (18) containing additives useful for passive fire protection, for example metallic metasilicates.

9. A method according to claim 5, wherein said passive fire protection device does not contain additives capable of releasing alkaline water at high temperature.

10. Use of a passive fire protection device as defined in any one of claims 1 to 4 for the passive fire protection of equipment, in particular safety- and security-important equipment 25 of an installation, for example of cables, cable trays, ventilation and smoke extraction ducts, crossings, joints and boxes.

11. Use according to claim 10 for wrapping cable trays, preferably in hazardous installations, such as nuclear power plants.

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