Passive fire protection device comprising a silicone foam

Abstract

The invention 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. Said passive fire protection device is particularly useful for the protection of equipment important for the security and safety of an installation, for example cables, cable troughs, ventilation and smoke removal ducts, feedthroughs, joints and cabinets.

Description

[0001] DESCRIPTION

[0002] TITLE: Passive fire protection device comprising silicone foam

[0003] Technical field

[0004] The present invention relates to the technical field of silicone foams, and more specifically the use of silicone foam strips for passive fire protection of equipment, in particular:

[0005] - cables and cable trays, ventilation and smoke extraction ducts;

[0006] - crossings (cables, steel, copper, stainless steel pipes, etc.), fire crossings;

[0007] - fire seals;

[0008] - fire-resistant boxes protecting specific devices, in particular devices important for the safety and security of an installation, for example pumps, valves, sensors or actuators.

[0009] Passive fire protection (PFP) refers to all preventive fire protection measures based on the use of fire breaks or fire-resistant structural elements. A PFP device is an item that allows a building or part of a building to withstand a fire for a predetermined period of time. The fire resistance of an installation can be verified and certified by tests conducted according to ISO EN 1366 "Fire resistance tests for technical installations".

[0010] State of the prior art

[0011] 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.).

[0012] Fire-resistant coverings are commonly used to protect cable trays. Passive fire protection covers are generally flexible devices with fire-resistant properties that have mechanical resistance up to 1300°C.

[0013] Examples of prior art documents include:

[0014] - 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.

[0015] - Patent application EP 2 072 087 A1 describes a fire protection mattress comprising at least two fibrous sub-assemblies based on layers of mineral fibre wool separated by a mineral fibre fabric, at least one layer of refractory glue joining the fibrous sub-assemblies together, and an envelope comprising a mineral fibre fabric impregnated with a fire-retardant silicone and enclosing all of the fibrous sub-assemblies.

[0016] - Patent application EP 2 694 164 A1 also describes a fire protection coating comprising several superimposed fibrous layers and a layer of refractory glue placed between two fibrous layers.

[0017] In these various documents, the firestop material contains at least one fibrous element. However, in the event of rupture, fibrous products can generate residues that are likely to clog the safety components of the installations, for example, cooling circuits. The presence of fibrous elements is therefore contraindicated in high-risk installations, such as nuclear power plants.

[0018] Patent application EP 3 799 935 A2 proposed a solution to this specific problem: it describes a fire protection blanket that comprises a first layer made of a fabric of a heat-resistant material, in particular a glass fabric or a fabric with meta-aramid fibers, and a second layer made of an intumescent material. In addition, this document describes a fire protection device using one or more of said blankets deposited in a staggered pattern. According to this document, fire protection blankets have the advantage of being light and flexible and of not risking projecting fibers that could clog filters in the event of damage to the cable tray protections in the event of blowing by a steam jet or other means. However, the assembly of these blankets is difficult: the blankets must be arranged in such a way as to provide areas for expansion of the intumescent material in the event of fire.

[0019] In this context, the present invention aims to propose a new passive fire protection device, flexible, lightweight and easy to handle, having fire-resistant properties and good mechanical resistance up to 1300°C. This new device is advantageously free of fibrous elements. It provides protection for equipment important for safety and security in high-risk installations, such as nuclear power plants. In addition, this new device can be removable, cleanable and decontaminable.

[0020] More generally, the present invention aims to propose a new device for passive fire protection of equipment, in particular equipment important for the safety and security of an installation, for example cables, cable trays, ventilation and smoke extraction ducts, bushings, joints and boxes.

[0021] Summary of the invention

[0022] 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 / cm 3 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:

[0023] - prepare a silicone composition capable of forming a foam by releasing a gas;

[0024] - depositing said composition in a mold;

[0025] - close the mold; and

[0026] - allowing said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

[0027] Furthermore, the invention relates to the use of said device for passive fire protection of equipment, in particular equipment important for the safety and security of an installation, for example cables, cable trays, ventilation and smoke extraction ducts, bushings, joints and boxes, and in particular for taping cable trays, preferably in high-risk installations, such as nuclear power plants.

[0028] Brief description of the figures

[0029] [Fig. 1] represents an embodiment of a mold according to the invention.

[0030] [Fig. 2] represents an embodiment of a strip before (2A) and after (2B) its demolding according to the present invention.

[0031] [Fig. 3] represents an embodiment of a passive fire protection device according to the invention.

[0032] [Fig. 4] is a photograph of a strip obtained according to the example according to the invention.

[0033] Detailed description of the invention

[0034] Unless otherwise indicated, all viscosities of the silicone oils discussed in this disclosure correspond to a dynamic viscosity quantity at 25°C known as “Newtonian”, i.e. 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.

[0035] 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 / cm 3 .

[0036] A strip can be defined as a shape whose thickness is significantly less than its length and width. A strip can typically be:

[0037] - between 50 cm and 5 m long; - between 10 cm and 50 cm wide;

[0038] - between 1 cm and 5 cm thick.

[0039] The term "silicone foam" or "silicone foam" refers to an organopolysiloxane composition in the form of a foam.

[0040] According to a preferred embodiment, the silicone foam according to the present invention is obtained from a silicone composition crosslinking by polyaddition and the foaming reaction of which generates hydrogen.

[0041] Without wishing to be bound by any theory, the foaming phenomenon can be described as follows: A polyaddition crosslinking composition is used comprising an organopolysiloxane bearing vinyl groups bonded to silicon, an organopolysiloxane containing hydrogen atoms bonded to silicon and a pore-forming agent comprising a hydroxyl group. The hydroxyl group of the pore-forming agent reacts with the hydride-functional organopolysiloxane, thus producing gaseous hydrogen and a silanol. The silanol then reacts with the hydride-functional organopolysiloxane by a hydrogen condensation reaction, thus generating a second molecule of gaseous hydrogen, while another polydiorganosiloxane bearing vinyl groups bonded to silicon will simultaneously react by an addition reaction with another hydride-functional polydiorganosiloxane, thus participating in the construction of the silicone foam network.

[0042] 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, insofar as the composition releases a gas allowing the foaming phenomenon. According to one embodiment, the silicone composition contains a pore-forming agent which expands the material under the action of heat by decomposition with release of gas, in particular the case of azo-type derivatives, for example azodicarbonamide, which will allow the release of nitrogen, carbon dioxide and ammonia. According to another embodiment, the silicone composition contains a pore-forming agent which expands the material under the action of heat by phase change, typically liquid to gas, in particular the case of solvents with a low boiling point.

[0043] According to a preferred embodiment, the silicone foam is obtained from a silicone composition comprising:

[0044] - at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon,

[0045] - at least one organopolysiloxane B having, per molecule, at least two SiH units,

[0046] - a catalytically effective amount of at least one hydrosilylation catalyst C, and

[0047] - at least one pore-forming agent D comprising a hydroxyl group.

[0048] Organopolysiloxane A having, per molecule, at least two alkenyl groups, C2-C12 linked to silicon, may preferably be a linear organopolysiloxane formed: - of at least two siloxyl units of the following formula: Y a R 1 bSiO(4-ab) / 2 in which Y represents a C2-C12 alkenyl group, preferably a vinyl group; R 1represents 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

[0049] - possibly patterns of the following formula: R 1 c SiO(4-o / 2 in which R 1 has the same meaning as above and c = 2 or 3.

[0050] It is understood in the above formulas that, if several R groups 1 are present, they can be the same or different from each other.

[0051] In the following section regarding the description of organopolysiloxane A, the following nomenclature has been used to represent the siloxyl units:

[0052] M: siloxyl unit R iSiO 1 2.

[0053] M V1 : siloxyl unit chosen from YR 1 2SiOi / 2 and Y2R 1 SiOi / 2,

[0054] D: siloxyl unit R x 2SiO2 / 2,

[0055] D V1 : siloxyl unit chosen from Y2SiO2 / 2 and YR 1 SiO2 / 2,

[0056] T: siloxyl unit R'SiO;2.

[0057] Q: siloxyl unit SiC>4 / 2, with Y and R 1 as defined above.

[0058] As examples of terminal motifs M and M V1 , we can cite the trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy groups.

[0059] As examples of patterns D and D V1 , we can cite the dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy groups.

[0060] Examples of T units include the methylsiloxy group.

[0061] The organopolysiloxane A having, per molecule, at least two alkenyl groups, C2-Ci2 linked to silicon, may preferably be a linear organopolysiloxane essentially consisting of siloxyl units D and / or D V1 , and terminal siloxyl units M and / or M V1 .

[0062] Examples of linear organopolysiloxanes which may be an organopolysiloxane A according to the invention are:

[0063] - a poly(dimethylsiloxane) with dimethylvinylsilyl ends;

[0064] - a poly(dimethylsiloxane-co-methylphenylsiloxane) with dimethylvinylsilyl ends;

[0065] - a poly(dimethylsiloxane-co-methylvinylsiloxane) with dimethylvinylsilyl ends; and

[0066] - a poly(dimethylsiloxane-co-methylvinylsiloxane) with trimethylsilyl ends. Preferably, organopolysiloxane A contains terminal dimethylvinylsilyl units and even more preferably organopolysiloxane A is a poly(dimethylsiloxane) with dimethylvinylsilyl ends.

[0067] Preferably, the organopolysiloxane A is an oil with a dynamic viscosity of between 100 mPa.s and 100,000 mPa.s, preferably between 100 mPa.s and 80,000 mPa.s, and more preferably between 1000 mPa.s and 50,000 mPa.s.

[0068] Preferably, the organopolysiloxane A has a mass content of alkenyl unit of between 0.001% and 30%, preferably between 0.01% and 10%, preferably between 0.02% and 5%.

[0069] The silicone composition preferably comprises from 40% to 80% by weight of organopolysiloxane A, even more preferably from 50% to 70% by weight of organopolysiloxane A. According to one embodiment, the silicone composition does not comprise branched organopolysiloxanes or resins comprising C2-C12 alkenyl units.

[0070] Organopolysiloxane B is an organopolysiloxane having, per molecule, at least two SiH units. It is therefore an organohydrogenpolysiloxane compound. Preferably, compound B comprises at least three SiH units.

[0071] Organopolysiloxane B may advantageously be an organopolysiloxane comprising at least two, preferably at least three, siloxyl units of the following formula: HdR 2 e SiO(4-de) / 2 in which R 2represents 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 optionally other units of the following formula: R 2 fSiO ( 4-f) / 2 in which R 2 has the same meaning as above, and f = 0, 1, 2, or 3.

[0072] It is understood that, if several R groups 2 are present in the above formulas, they can be the same or different from each other.

[0073] Preferably, R 2 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. R 2may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0074] The symbol d is preferably equal to 1.

[0075] In the following section regarding the description of organopolysiloxane B, the following nomenclature has been used to represent the siloxyl units:

[0076] M: siloxyl unit R 2 3SiOi / 2, M': siloxyl unit R 2 2HSiOi / 2, D: siloxyl unit R 2 2SiO2 / 2, D': siloxyl unit R 2 HSiC>2 / 2,

[0077] T: siloxyl unit R 2 SiOs / 2,

[0078] Q: siloxyl unit SiC>4 / 2, with R 2 as defined above.

[0079] 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.

[0080] When it comes to linear polymers, these are essentially made up of D and / or D' siloxyl units, and M and / or M' terminal siloxyl units. When it comes to cyclic polymers, these are essentially made up of D and / or D' siloxyl units.

[0081] Examples of organohydrogenpolysiloxanes which may be organopolysiloxanes B according to the invention are:

[0082] - a poly(dimethylsiloxane) with hydrogenodimethylsilyl ends;

[0083] - a poly(dimethylsiloxane-co-methylhydrogensiloxane) with trimethylsilyl ends;

[0084] - a poly(dimethylsiloxane-co-methylhydrogensiloxane) with hydrogenodimethylsilyl ends;

[0085] - a poly(methylhydrogensiloxane) with trimethylsilyl ends; and

[0086] - a cyclic poly(methylhydrogensiloxane).

[0087] When organopolysiloxane B has a branched structure, it is preferably chosen from the group consisting of silicone resins of the following formulae:

[0088] - M'Q where the hydrogen atoms linked to silicon atoms are carried by the M groups;

[0089] - MM'Q where the hydrogen atoms linked to silicon atoms are carried by a part of the M patterns;

[0090] - MD'Q where the hydrogen atoms linked to silicon atoms are carried by the D groups;

[0091] - MDD'Q where the hydrogen atoms linked to silicon atoms are carried by part of the D groups;

[0092] - MM'TQ where the hydrogen atoms linked to silicon atoms are carried by part of the M motifs;

[0093] - MM'DD'Q where the hydrogen atoms linked to silicon atoms are carried by part of the M and D motifs;

[0094] - and their mixtures.

[0095] Preferably, the organopolysiloxane B has a mass content of Si-H hydrogenosilyl functions of between 0.2% and 91%, more preferably between 3% and 80% and even more preferably between 15% and 70%. Advantageously, the molar ratio of the Si-H hydrogenosilyl 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.

[0096] The silicone composition according to the invention preferably comprises from 1% to 20% by weight, and more preferably from 3% to 15% by weight, of organopolysiloxane B.

[0097] The hydrosilylation catalyst C may in particular be chosen 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, it is possible to 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 vinyl organosiloxanes described in US patents 3,419,593, US 3,715,334, US 3,377,432 and US 3,814,730.

[0098] Preferably, catalyst C is a compound derived from platinum. In this case, the weight quantity of catalyst C, calculated as the weight of platinum metal, 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.

[0099] Preferably, catalyst C is a Karstedt platinum.

[0100] The pore-forming agent D comprising a hydroxy group Ic 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.

[0101] According to a preferred embodiment, the pore-forming agent D is water. The water may be added directly into the silicone composition. Alternatively, the water may 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 one embodiment, the water is introduced via an emulsion of silicone oil in water with a water content of the order of 60% by weight. When the water is introduced into the silicone composition via an emulsion, the dispersion of the water in the silicone composition and its storage stability are improved.

[0102] According to another embodiment, the pore-forming agent 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 that may be mentioned are 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 pore-forming agent according to the invention are:

[0103] - diols, for example 1,2-ethanediol, 2,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol;

[0104] - triols, for example 1,2,3-propanetriol and 2,2-bis-hydroxymethyl-butanol;

[0105] - tetritols, for example erythritol and pentaerythritol;

[0106] - pentitols, for example arabitol, xylitol, and methylpentitol;

[0107] - hexitols, for example mannitol and sorbitol; and

[0108] - cycloaliphatic polyols, for example cyclohexanediols, cyclohexane triols, and inositol.

[0109] According to another embodiment, the pore-forming agent 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 pore-forming agent according to the invention are methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, n-octanol, benzyl alcohol, and mixtures thereof.

[0110] According to yet another embodiment, the pore-forming agent D is an organosilane containing one or more silanol groups. These compounds may for example be represented by the following formula (1) or formula (2):

[0111] (1) (R 3 )3SiOH

[0112] (2) (R 3 )2Si(OH)2 in which R 3 represents 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 10 carbon atoms and aryl groups having 6 to 12 carbon atoms. It is understood that, if several R groups 3 are present in the above formulas, they can be the same or different from each other.

[0113] Examples of organosilanes containing one or more silanol groups that can be used as a blowing agent according to the invention are (CH3)3SiOH, (CdHySiOH, (ŒLXCôHs^SiOH and (C6H5)2Si(OH)2.

[0114] According to yet another embodiment, the pore-forming agent D is an organosiloxane containing one or more silanol groups. Preferably, it may be an organopolysiloxane compound formed:

[0115] - at least one siloxyl unit of the following formula: R 3 g (OH)hSiO(4- g -h) / 2 in which R 3 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

[0116] - possibly patterns of the following formula: R 3 iSiO ( 4-i) / 2 in which R 3 has the same meaning as above and i = 0, 1, 2 or 3.

[0117] The silicone composition may further comprise other compounds, in particular:

[0118] - at least one mineral filler, in particular silica, quartz, or a mixture thereof; - at least one thermal resistance and / or fire resistance additive;

[0119] - at least one diorganopolysiloxane gum;

[0120] - a diorganopolysiloxane oil blocked at each end of its chain by a triorganosiloxy unit whose organic radicals linked to the silicon atoms are chosen from alkyl radicals having from 1 to 8 carbon atoms;

[0121] - a crosslinking inhibitor;

[0122] - a coloring base;

[0123] - optionally other charges.

[0124] 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 m 2 / g and 400 m 2 / g, preferably greater than 70 m 2 / g, an average primary particle size of less than 0.1 pm (micrometer) and an apparent density of less than 200 g / liter. Very preferably, the mineral filler is a combustion silica with a specific surface area of ​​between 100 m 2 / g and 300 m 2 / g.

[0125] The silica-type mineral fillers, preferably hydrophilic, may be incorporated as such into the silicone composition or may optionally be treated with a compatibilizing agent. According to a variant, these silicas may optionally be treated with one or more organosilicon compounds, for example organosilane or organosilazane, usually used for this purpose. These compounds include methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclo-tetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyl-dichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyl-dimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane.These compounds can be used alone or in a mixture (see French patents FR 1 126 884, FR 1 136 885, FR 1 236 505 and English patent GB 1 024 234). According to a preferred embodiment, the silica is treated during mixing with all or part of the organopolysiloxane A according to an in-situ process. According to an advantageous embodiment, the silica is treated with one or more hexaorganodisilazanes. Even more preferably, the silica is treated with hexamethyldisilazane alone or in a mixture with divinyltetramethyldisilazane.

[0126] The silica may optionally be predispersed in a silicone oil, so as to obtain a suspension. It is particularly preferred to use a suspension of treated combustion silica, in particular with hexamethyldisilazane, in a polyorganosiloxane oil, in particular vinylated.

[0127] Alternatively or in addition, the silicone composition according to the invention may also contain at least one other mineral filler which is a quartz. Preferably, a 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. 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.

[0128] Other mineral fillers may be considered, including bulking fillers, such as diatomaceous earth, calcium carbonate and / or kaolin.

[0129] The silicone composition may optionally comprise at least one thermal resistance and / or fire resistance additive. These thermal resistance and / or fire resistance additives are well known to those skilled in the art. It may advantageously 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 earths such as cerium and lanthanum; organophosphorus compounds; platinum derivatives; carbon black; and calcium, aluminum and / or potassium silicates such as, for example, mica and wollastonite. Mention may also be made of hydrated mineral fillers, oxides or carbonates of calcium, magnesium or aluminum, such as magnesium hydroxide Mg(OH)2, aluminum hydroxide A1(OH)3, hydromagnesite of empirical formula Mg5(CO3)4(OH)2.4H2O, and calcium hydroxide.According to another embodiment, hollow glass microspheres can be added to the silicone composition.

[0130] The silicone composition may optionally comprise 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 consists essentially of units of formula R2SiO2 / 2 and blocked at each end by units of formula R3SiO1 / 2, the radical R represents 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 quantities of units other than R2SiO2 / 2, for example units RSiO3 / 2 and / or SiC>4 / 2, is however not excluded in the proportion of at most 2% relative to the number of units R2SiO2 / 2. Preferably, the diorganopolysiloxane gums comprise at least two C2-C12 alkenyl groups bonded to silicon.Advantageously, the diorganopolysiloxane gum has a mass content of vinyl units 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%.

[0131] When the silicone composition comprises a crosslinking inhibitor (or addition reaction retarder), 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,H-dodecyne-1-ol-3, diphenyl-1,1-propyne-2-ol-1, rethyl-3-ethyl-6-nonyne-1-ol-3 and methyl-3-pentadecyne-1-ol-3.

[0132] According to one embodiment, the silicone composition comprises (by weight relative to the total weight of the silicone composition): a. from 40% to 80% by weight of at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups bonded to silicon, b. from 1% to 20% of at least one organopolysiloxane B having, per molecule, at least two SiH units and preferably at least three SiH units, c. from 2 ppm to 400 ppm by weight of a hydrosilylation catalyst C chosen from platinum compounds (quantity calculated by weight of platinum metal), and d. from 0.3% to 2.5% by weight of a pore-forming agent D, e. at least 3% by weight of a combustion silica whose specific surface area is between 100 m 2 / g and 300 m 2 / g, f. at least 6% by weight of at least one mineral filler which is ground quartz, and g. from 0.4% to 5% by weight of at least one thermal resistance and / or fire resistance additive.

[0133] According to another embodiment, the silicone composition comprises (by weight relative to the total weight of the silicone composition): a. from 40% to 80% by weight of at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups bonded to silicon, b. from 1% to 20% by weight of at least one organopolysiloxane B having, per molecule, at least two SiH units and preferably at least three SiH units, c. from 2 ppm to 400 ppm by weight of a hydrosilylation catalyst C chosen from platinum compounds (quantity calculated by weight of platinum metal), d. from 0.3% to 2.5% by weight of a pore-forming agent D, e. from 3% to 14% by weight of at least one mineral filler which is a combustion silica whose specific surface area is between 100 m 2 / g and 300 m 2 / g, f. from 6% to 25% by weight of at least one mineral filler which is ground quartz, g. from 0.4% to 5% by weight of at least one fire resistance additive, h. from 0 to 3000 ppm by weight of a crosslinking inhibitor, and i. from 0 to 4% by weight of a diorganopolysiloxane gum comprising at least two C2-C12 alkenyl groups bonded to silicon.

[0134] Such a silicone composition allowing the production of a silicone foam is for example described in international patent application WO 2021 / 014058.

[0135] 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 presented in two (or more) distinct parts intended to be mixed to form said silicone composition. In particular, in the case of the 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 can be provided to improve the storage 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 presented in three distinct parts intended to be mixed to form said silicone composition.

[0136] The mixing of the parts of said two-component (or multi-component) system can typically take place in a mixer (mechanical agitator with inclined blades, low-pressure dynamic mixer, or any other conventional agitation system) at a temperature close to room 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 shear applied. If it is desired to accelerate the crosslinking or curing of the silicone foam, the mixing can be carried out at a higher temperature, advantageously between 40°C and 70°C.

[0137] It is important to have good mixing quality to obtain a homogeneous silicone foam with good mechanical properties.

[0138] The silicone composition undergoes a crosslinking and / or curing step to obtain the silicone foam. This step can have a variable 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.

[0139] 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.

[0140] In addition to its lightness, the silicone foam according to the invention advantageously has good mechanical properties, excellent fire resistance and does not release toxic fumes during combustion.

[0141] Thanks to these remarkable properties, silicone foam is flexible and easy to handle, and can be used advantageously in a passive fire protection device.

[0142] 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.

[0143] 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: - preparing a silicone composition capable of forming a foam by release of a gas;

[0144] - depositing said composition in a mold;

[0145] - close the mold; and

[0146] - allowing said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

[0147] 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 Figure 1.

[0148] Preferably, the bottom and top walls of the mold define the largest surfaces of the molded article, while the side walls define the thickness of the molded article.

[0149] According to a first embodiment illustrated by Figure 1, the mold (1) consists of side walls (2) (four side walls are shown here), a bottom wall (3) and an upper wall or cover (4). The bottom wall (3) can optionally be provided with feet (5) serving as support for the mold. The cover (4) is preferably removable, as illustrated in Figure 1. When preparing the strip according to the present invention, the silicone composition can be deposited in the mold (1) (configuration IA), then the cover (4) can be fixed to the side walls, thus defining a closed hollow volume (configuration IB).

[0150] According to another embodiment (not shown), the mold may consist of two half-molds which define a closed hollow volume when they are assembled. When implementing the method according to the present invention, the silicone composition may typically be injected into the closed hollow volume defined by the 2 assembled half-molds.

[0151] The walls of the mold can be made of a material suitable for ensuring its mechanical strength, for example metal, typically steel or aluminum, rigid plastic, typically PET, polypropylene or polycarbonate, or a composite material.

[0152] According to a preferred embodiment, the mold comprises a means for evacuating the gases generated during the crosslinking and / or curing reaction of the silicone composition. In one embodiment, at least part of the walls of the mold according to the invention are made of two adjacent materials: a rigid outer material permeable to gas, for example a grid or a perforated plate, and an inner material permeable to gas and impermeable to liquid. Indeed, since the silicone composition is deposited in 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 curing reaction. Preferably, said internal material is made of a flexible material, typically a fibrous material. Said fibrous material may be of natural, artificial and / or synthetic origin. It may be a woven, knitted or non-woven fibrous material.When it comes to a woven or knitted fibrous support, i.e. a fabric or a knit, the threads are advantageously based on thermoplastic polymer.By way of example, suitable thermoplastic (co)polymers include: polyolefins, polyesters, polyalkylene oxides, polyoxyalkylenes, polyhaloalkylenes, poly(alkylene phthalate or terephthalate), poly(phenyl or phenylene), poly(phenylene oxide or sulfide), polyvinyl acetates, polyvinyl alcohols, polyvinyl halides, polyvinylidene halides, polyvinyl nitriles, polyamides, polyimides, polycarbonates, polysiloxanes, polymers of acrylic or methacrylic acid, 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 one of the monomers included in the polymers. above-mentioned, as well as mixtures and / or alloys of all these (co)polymers.When the fibrous material is made of thermoplastic polymer, it is preferably made of polyester, such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), their copolymers and blends, or of 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 blends.

[0153] Still according to this preferred embodiment, at least the lower and upper walls of the mold are provided 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.

[0154] After the silicone composition has been deposited, the mold can be closed, for example using a lid, as illustrated in Figure 1B. The hollow volume defined by the closed mold should preferably remain fixed and withstand the pressure created by the expansion of the foam. Fixing means 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.

[0155] The preparation of the strip finally includes a step consisting of allowing said silicone composition to crosslink and / or harden to obtain the silicone foam. This step can have a variable duration depending on the silicone composition and the temperature of the previous 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.

[0156] Advantageously, the entire silicone foam manufacturing process is carried out under air or nitrogen scavenging to avoid risks associated with hydrogen release during the process. In addition, the silicone foam manufacturing process is preferably carried out at atmospheric pressure and room temperature, also to avoid risks associated with hydrogen release. The room 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 room temperature is a significant advantage in terms of technological simplification and implementation costs.

[0157] The method according to the present invention may optionally comprise an additional step consisting of annealing the silicone foam. This optional annealing step may consist of a heat treatment lasting from 1 to several hours, preferably from 1 to 4 hours, at a temperature between 50°C and 200°C, preferably between 100°C and 150°C. It may make it possible to improve, if necessary, the fire resistance and the mechanical properties of the silicone foam. However, this step is not essential, and a method characterized in that it does not comprise an additional annealing step will be preferred.

[0158] After crosslinking and / or curing, and optionally annealing, a strip comprising a silicone foam is obtained and it 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 crosslinking and / or curing, then in contact with the silicone foam after its crosslinking and / or curing, is chosen so that demolding is easy. For this, the material is chosen from materials adhering little or not at all to the silicone foam after its crosslinking and / or curing. Preferably, the material of the inner face of the mold is made of polyester. Alternatively, the material can be surface-treated to improve its non-adhesion to the silicone foam, for example with a fluorocarbon coating.

[0159] In addition to the silicone foam, the passive fire protection device according to the present invention may advantageously comprise a textile support. Textile supports 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 support 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. The glass fabric has the advantage of being inexpensive and offering good mechanical strength.

[0160] According to a preferred embodiment, the strip comprises a layer of silicone foam and a textile support. In this context, step (A) of preparing the strip further comprises a step of placing a textile support 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:

[0161] - prepare a silicone composition capable of forming a foam by releasing a gas;

[0162] - place a textile support in a mold;

[0163] - depositing said composition on said textile support;

[0164] - close the mold; and

[0165] - allowing said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

[0166] After crosslinking and / or curing, the silicone foam obtained adheres to the textile support. The strip comprising the silicone foam layer and the textile support can be demolded. Figure 2 shows a strip thus obtained before its demolding (configuration 2A) and after its demolding (configuration 2B). The strip (9) comprises a textile support (7) and a silicone foam layer (8) which adheres to the textile support (7). According to the illustrated embodiment, certain internal walls of the mold (1) and the cover (4) have been coated with a non-stick polyester fibrous material (6). During demolding, the cover (4) is dismantled and the strip (9) can be easily removed from the mold (1).

[0167] Advantageously, the strip may not include an adhesion primer between the silicone foam layer and the textile support. Indeed, in the preparation method described above, the crosslinking and / or hardening reaction of the silicone foam takes place directly on the textile support and adhesion is thus obtained without additional adhesion primer.

[0168] The method of manufacturing a passive fire protection device according to the present invention may further comprise (B) assembling one or more of said strips comprising a silicone foam.

[0169] The assembly can be carried out by a person skilled in the art using methods known in the technical field. A device can comprise several thicknesses of strips assembled together mechanically and / or chemically (bonding). For example, a strip comprising a silicone foam according to the invention can be wound on itself. According to another example, several strips according to the invention can be stacked on top of each other. Between each strip, an intermediate layer can optionally be positioned. This can optionally contain additives useful for passive fire protection and / or for mechanical reinforcement.

[0170] 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" is meant a compound which prevents or inhibits the spread of fire. Mention may in particular be made of metal hydroxides, which under the effect of heat decompose and release water. Among the metal hydroxides most used for their passive fire protection properties, mention may be made of aluminum hydroxide (ATH) and magnesium hydroxide.The use of refractory particles is for example described in patent application EP 2 072 087 AL It may in particular be metal metasilicates, for example hydrated sodium metasilicate (Na2SiO3.nH2O). The use of such additives advantageously makes it possible to improve the fire resistance properties of the device and to delay the increase in temperature of the equipment it is intended to protect.

[0171] According to an alternative embodiment, the passive fire protection device according to the present invention does not contain additives capable of releasing basic water at high temperature. In particular, the passive fire protection device according to the present invention does not contain metal metasilicates. Without wishing to be bound by this theory, the inventors believe that the silicone foam strip could be degraded at high temperature by alkali metal hydroxides, which may be released by the metal metasilicates.

[0172] Figure 3 shows an embodiment of a passive fire protection device (10) according to the invention comprising 3 thicknesses of strips arranged around a cable tray (11). The first thickness of strip comprises a first layer of silicone foam (12) and a first textile support (13). This first thickness of strip is assembled with a second thickness of strip which comprises a second layer of silicone foam (14) and a second textile support (15). This second thickness of strip is assembled with a third thickness of strip which comprises a third layer of silicone foam (16) and a third textile support (17). Between each thickness of strip is an intermediate layer (18), which may contain additives useful for passive fire protection and / or for mechanical reinforcement.However, according to an embodiment not shown, the passive fire protection device (10) according to the invention does not comprise an intermediate layer (18), the strip thicknesses then being directly adjacent to each other.

[0173] The first, second and third strips, comprising a silicone foam layer and a textile support layer, may have a thickness typically between 1 cm and 3 cm. The intermediate layers may have a thickness typically between 0 cm and 2 cm. The entire device after assembly may therefore have a thickness, according to this embodiment, between 3.2 cm and 13 cm.

[0174] Furthermore, the invention relates to the use of said passive fire protection device for equipment, in particular equipment that is important for the safety and security of an installation. Among the equipment concerned, we can cite for example:

[0175] - cables and cable trays, ventilation and smoke extraction ducts;

[0176] - crossings (cables, steel, copper, stainless steel pipes, etc.), fire crossings;

[0177] - fire seals;

[0178] - fire-resistant enclosures protecting specific devices, in particular devices important for the safety and security of an installation, for example pumps, valves, sensors or actuators.

[0179] In particular, the equipment concerned may be chosen from equipment important for the safety and security of an installation, in particular 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 taping cable trays, preferably in high-risk installations, such as nuclear power plants. According to another specific embodiment, the invention relates to the use of said passive fire protection device for manufacturing hopper sleeves, in particular cables, tubes or pipes.

[0180] In addition to being free of fibrous elements, ensuring safety and security in high-risk installations, the passive fire protection device proposed by the present invention has been eco-designed to be light, flexible, easy to handle, removable, cleanable and decontaminable. The device can be dismantled and reassembled on the installations, without having to replace it entirely with a new device. The negative impact of the product on the environment over its entire life cycle can thus be reduced, while retaining its qualities of use.

[0181] Other details or advantages of the invention will appear more clearly from the examples given below for information purposes only.

[0182] Examples 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:

[0183] [Table 1]

[0184] In a mold consisting of a perforated steel frame measuring 150x35x2 cm, a polyester fabric was placed in the bottom, followed by a commercial glass fabric approximately 2 mm thick. A lid, also made of a perforated steel plate, was covered with a polyester fabric.

[0185] The silicone composition was placed in the mold on the glass fabric, spread evenly at the bottom of the mold using a scraper (liquid layer of around 3 mm), then the cover was fixed to the frame so as to form a closed mold.

[0186] After 45 minutes at 23°C, the resulting foam was demolded. As can be seen in Figure 4, the resulting strip comprises a glass fabric and a layer of silicone foam. The density of the foam is approximately 0.15 g / mL. The silicone foam adheres perfectly to the supporting glass fabric. The resulting strip is homogeneous, light and flexible. It can be easily handled and folded.

[0187] An installation protected by the strip obtained as described above is tested in accordance with the European standard EN 1366-3. After passing the fire resistance test, the overall system obtains the classification El 120. This is the classification of the fire behavior of construction products (E = Sealing - ability of a component with a partitioning function to resist fire penetration from the non-ignited side; I = Insulation - ability to prevent heat transfer during unilateral exposure to fire as long as no surface or material is ignited on the non-ignited side) and the duration of fire resistance (120 = Duration in minutes - time during which all criteria E and I are met).

Claims

CLAIMS 1. Passive fire protection device, said device comprising at least one strip comprising a silicone foam having a density of less than 0.20 g / cm 3 .

2. Passive fire protection device according to claim 1, in which the silicone foam is obtained from a silicone composition crosslinking by polyaddition and the foaming reaction of which generates hydrogen.

3. Passive fire protection device according to claim 1 or claim 2, wherein the silicone foam is obtained from a silicone composition comprising: - at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, - at least one organopolysiloxane B having, per molecule, at least two SiH units, - a catalytically effective amount of at least one hydrosilylation catalyst C, and - at least one pore-forming agent 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. from 40% to 80% by weight of at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups bonded to silicon, b. from 1% to 20% of at least one organopolysiloxane B having, per molecule, at least two SiH units and preferably at least three SiH units, c. from 2 ppm to 400 ppm by weight of a hydrosilylation catalyst C chosen from platinum compounds (quantity calculated by weight of platinum metal), and d. from 0.3% to 2.5% by weight of a pore-forming agent D, e. at least 3% by weight of a combustion silica whose specific surface area is between 100 m 2 / g and 300 m2 / g, f. at least 6% by weight of at least one mineral filler which is ground quartz, and g. from 0.4% to 5% by weight of at least one thermal resistance and / or fire resistance additive.

5. Passive fire protection device according to any one of claims 1 to 4, said passive fire protection device comprising a textile support.

6. Passive fire protection device according to claim 5, in which the strip does not comprise an adhesion primer between the silicone foam layer and the textile support.

7. A method of preparing a passive fire protection device according to any one of claims 1 to 6, said method comprising (A) preparing 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; - depositing said composition in a mold; - close the mold; and - allowing said silicone composition to crosslink and / or harden to obtain the strip comprising the silicone foam.

8. Method for preparing a passive fire protection device according to claim 7, in which the mold comprises a means allowing the evacuation of gases generated during the crosslinking and / or hardening reaction of the silicone composition.

9. A method of preparing a passive fire protection device according to claim 7 or claim 8 further comprising (B) assembling one or more of said strips comprising a silicone foam.

10. The method of claim 7, wherein said passive fire protection device further comprises one or more layers containing additives useful for passive fire protection, for example metal metasilicates.

11. The method of claim 7, wherein said passive fire protection device does not contain additives capable of releasing basic water at high temperature.

12. Use of a passive fire protection device as defined in any one of claims 1 to 6 for the passive fire protection of equipment, in particular equipment important for the safety and security of an installation, for example cables, cable trays, ventilation and smoke extraction ducts, bushings, joints and boxes.

13. Use according to claim 12 for wrapping cable trays, preferably in high-risk installations, such as nuclear power plants.

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