FR2640658A1 - Organic coating for protecting structures, especially against fire and heat - Google Patents

Abstract

The coating comprises a mineral filler in the form of grains and/or fibres, coated with an organic binder. It additionally comprises at least one inorganic compound contributing molecules of water of crystallisation to the coating. Use for protecting structures, especially against fire and heat.

Description

 The present invention relates to a coating for protecting buildings, in particular against fire and heat.

 The word coating is designated below in its strict sense by excluding intumescent paints which do not exhibit stability over time.

 By "constructions", the following are mainly used to designate the walls, ceilings, roofs, doors and frames of apartment buildings or industrial or agricultural premises, garages, hangars, made of beams, metal or wooden beams and posts, solid or openwork trusses or trusses, partitions, plastic panels, in enamelled or painted sheet metal, in expanded materials as well as false ceilings and their suspension profiles, fire shields, ventilation ducts, smoke and fire conduits, transport pipes, in particular of petroleum products and similar flammable materials, and their jointing, electric cable trays, electric cable passages, safes, sound insulation panels and / or thermal, pipes, and sanitary facilities.

 By “constructions”, the following description will also denote floating structures such as ships, as well as storage tanks for flammable products, such as petroleum and chemical products, carcasses of hydraulic or atomic turbines, reactors atomic and the like.

 To protect the aforementioned constructions against the effects of fire and heat, products based on asbestos, ceramic fibers, rock wool or glass, and / or mineral particles have already been commonly used. coated in an inorganic or organic binder.

 There is thus known, for example, an anti-fire product, used in particular for the protection of electric cables, including an organic binder, based on synthetic materials such as: nylon, styrene butadiene copolymer, polyvinyls, and a charge of mineral particles to calcium carbonate base, talc (magnesium silicate), mica, very fine silica, clay (kaolin), possibly cellulose (such as pulp).

 This anti-fire product gives extremely precarious fire protection, of the order of about a quarter of an hour. The protection of most electric cables will not shine until the temperature reaches 3000C.

however, in the event of prolonged fire and / or direct contact with the flames, the protection provided is almost zero. Indeed, a person skilled in the art knows that polyvinyls decompose and / or burn at relatively low temperatures, below 3000C, so that the coating loses its consistency and no longer provides any protection as soon as this temperature is reached.

 We also contact, according to European Patent No. 0 029 883 in the name of the Applicant, a coating to protect constructions, in particular against fire and heat, comprising refractory particles coated with an inorganic binder hardenable in the presence of water, and at least one inorganic compound providing the coating or forming; crs of setting the inorganic binder a number of molecules of water of crystallization- greater than that normally obtained by the binder alone.

 Experience has shown that it was thus possible, by the presence of such an inorganic compound providing molecules of water of crystallization, to considerably increase the protection against fire obtained by the coating.

 However, such a coating is relatively expensive and may have adhesion difficulties, both at the time of its application and after it, on certain vertical smooth walls or overhanging such as walls of ventilation ducts or ducts. smoke, which are usually metallic.

 The object of the present invention is to remedy the drawbacks of known coatings, and to provide a protective coating which is inexpensive, which has excellent adhesion even on smooth vertical or overhanging walls, which is easy to use and which gives excellent protection against prolonged fire or direct contact with flames.

 The coating to protect constructions, in particular against fire and heat1 aimed by the invention takes a mineral filler in grains and / or fibers coated in an organic binder.

 According to the invention, the coating is characterized in that it comprises at least one inorganic compound providing the coating with molecules of water of crystallization.

 The coating according to the invention therefore differs from the aforementioned European patent No. 0029883 in the name of the applicant in that it comprises an organic binder in place of an inorganic binder curable in the presence of water, which is generally a hydraulic binder, cement, quicklime, etc. Such a substitution seems particularly daring in the case of a protective coating against fire and heat when we know the highly flammable and very combustible nature of organic binders.

 Although the organic binders decompose and / or burn at a temperature often below 300 C, which strongly dissuades the skilled person from using an organic binder in a coating intended to provide lasting protection against fire and liming , experience has shown this surprising result that it was thus possible to considerably increase the fire protection obtained by the coating.

 The Applicant has found that, like the coating which is the subject of the aforementioned European patent, the coating according to the present invention, when exposed to heat or fire, rises much slower in temperature than the known coatings, the average rate of rise in temperature being all the more reduced as the number of molecules of water of crystallization contained in this coating was more important.

 Without the invention being linked to this explanation, the applicant believes that this property results from the fact that the release of the water of crystallization requires a significant supply of heat which has the effect of maintaining the temperature of the coating at a low temperature included between around 80 and 2000C until the water of crystallization has been released: the decomposition or combustion of the organic binder is thus prevented, so that the coating according to the invention provides excellent protection against fire and heat.

 The organic binder, which is an inexpensive product, makes it possible to produce an inexpensive coating having excellent adhesion, even on smooth walls such as metallic walls, vertical or overhanging, without any subject of use of the type of those linked to the phenomena of hydraulic setting, and without the obligation of a pre-gluing of the wall before the installation of the coating.

 The absence of such phenomena of hydraulic setting means that there is no reason to fear the appearance of cracks.

 According to a first version of the invention, the mineral filler in grains and / or in fibers comprises materials such as silicates or phosphates of aluminum, calcium, magnesium or their compounds, for example, chalk, talc, clay, kaolin , mica, silica, colloidal silica, alumina, wcllastonite, perlite, vermicullte, aluminous or silico-magnesian silico products, magnesia, etc., or mixtures thereof.

 This load therefore includes very common and inexpensive materials, easy to handle and use.

According to an advantageous version of the invention, the organic binder comprises at least one organic compound soluble in water or capable of forming a dispersion in water. This compound can be chosen from homopolymers and copolymers of butadiene styrene or vinyl acetate, esters of acrylic acid, nylon, latex, vinyl or phenolic adhesives, urea adhesives, urea-formaldehyde or phencl-formaldehyde adhesives, epoxy or polyurethane systems and mixtures of these compounds.

 The use of such organic compounds which are soluble in water or capable of forming dispersions in water makes it very easy to prepare and apply the coating. The latter can thus be prepared and delivered in a closed box as a ready-to-use mixture containing an excess of water. As a variant, the coating can be prepared and delivered in the form of a dry mixture intended to be mixed with water before use, which makes it possible, for example, to spray it pneumatically.

 According to an advantageous version of the invention, the inorganic compound providing the coating with molecules of water of crystallization comprises at least one compound chosen from hydrated alumina, hydrated caustic soda, sodium carbonate deca-hydrate (Naz C0. l0H2O), magnesium carbonate trihydrate (Mg C03.3HzO), magnesium nitrate hexahydrate (Mg (N03) ?. 6H20), aluminum and potassium sulfate dodecahydrate (A1K (S04) 2.12H20) aluminum and ammonium dodecahydrate (AlNH4 (SO) 2.l2H2O), aluminum sulfate and. sodium dodecahydrate (A1Na (S04) 2.12Hz0), magnesium sulfate heptahydrate (MgS04.7H20), hydrated alum, in particular potassium. and ammonium, trisodium phosphate dodecahydrate (Na3 PO4.12H2O), hydrated alkaline and alkaline earth phosphates, sodium silicate pentahydrate (NazSiOs.HzO), sodium metasilicate, sodium tetraborate decahydrate (Na2B40z.10H20 ), and their mixtures.

 These corposés can be very easily supplied and used, do not risk increasing the cost of preparation and installation of the coating according to the invention.

According to a first preferred version of the invention, the coating according to the invention has the following dry weight composition
- organic binder: around 20 to 98%,
- mineral filler in grains and / or fibers and flame retardants: approximately 0 to 50%,
- inorganic compounds providing molecules of water of crystallization: approximately 2 to 80%
- other constituents, paper pulp, and / or cellulose, surfactants: approximately 0 to 20%.

According to another preferred version of the invention, the coating according to the invention has the following composition by weight, in the dry state
- organic binder: approximately 0.5% to 20%,
- mineral filler in grains and / or fibers, and flame retardants: more than 50%,
- inorganic compounds providing molecules of crystalline water: around 2 to 30%,
- other constituents: pulp, and / or cellulose, surfactants: approximately 0 to 20%.

 According to another preferred version of the invention, the covering is provided with strong insulating panels essentially comprising mineral fibers, for example in the form of basalt wool, rock wool, glass or slag, ceramic wool or their mixtures, coated in an organic binder which ensures the connection between the fibers, and an inorganic compound providing molecules of water of crystallization, and the inorganic compound providing molecules of water of crystallization is distributed regularly in the thickness of the panels.

 Other features and advantages of the invention will become apparent in the description below.

 According to the invention, the coating for protecting constructions, in particular against fire and heat, comprises a mineral filler in grains and / or in fibers coated in an organic binder. It further comprises at least one inorganic compound providing the coating with molecules of water of crystallization.

 The mineral filler in grains and / or fibers includes, for example, materials such as chalk, talc, clay, kaolin, mica, silica, colloidal silica, alumina, wollastonite, perlite, vermiculite, silicoaluminous or silico-magnesium compounds, magnesia , etc, or their mixtures. This filler can obviously also include other materials commonly used in protective coatings, such as, for example, ariante, inorganic fibers, fluxes such as fluorspar, calcium borate, iron oxide.

 The organic binder comprises at least one organic compound soluble in water or capable of forming a dispersion in water. This compound can be chosen, for example, from homopolymers and copolymers of butadiene styrene or vinyl acetate or esters of acrylic acid, latex, nylon, vinyl or phenolic adhesives, urea-based adhesives , ureaformol or phenol-formaldehyde adhesives, epoxy or polyurethane systems and mixtures of these compounds.

It can thus thus comprise, for example, nylons, butadiene styrene copolymers or vinyl acetate with dibutyl ester maleate or an ester of versatic acid or an ester of acrylic acid or ethylene or ethylene and vinyl chloride, or copolymers of an ester of acrylic acid with another ester of this acid or with styrene, all of these compounds being capable of forming dispersions with water, such as dispersions for paints and coatings intended for the building trade, marketed in France under the trade mark registered MOU LITS by the French Company
HOECHST. It can be part of epoxy or polyurethane systems and their mixtures.

 The inorganic compound providing the coating with molecules of water of crystallization comprises at least one compound chosen for example hydrated alumina, hydrated caustic soda, sodium carbonate (Na2CO3 .10Xz0), magnesium carbonate trihydrate (MgCO3 .3X2 O ), magnesium nitrate hexahydrate (Mg (NO3) 2.6HzO), aluminum sulphate and potassium dodecahydrate (A1K (So4) 2.12H2O), aluminum sulphate and ammonium dodecahydrate (AlNH4 (5C4) 2.12 H2O), aluminum sulphate and sodium dodecahydrate (AlNa (SO4) 2.12H2O), aluminum sulphate octodecahydrate (Al2 (SO4) 3 18H20), magnesium sulphate heptahydrate (NgSO4. 7H2O), hydrated alums , in particular potassium and ammonium, trisodium phosphate dodecahydrate (Na3PO4.12XzO), alkaline and alkaline earth phosphates hydrates, sodium silicate pentahydrate (Na2 SIO.5H2O), sodium metasilicate, sodium tetraborate decahydrate (Na2B4 O7.10H2 O), and mixtures thereof es.

 All of these compounds are readily available and usable.

 It is thus known that hydrated trisodium phosphate contains more than 54% by weight of water, and releases it around 700C.

 The coating can also, in known manner, also comprise at least one so-called flame retardant compound such as antimony oxide, boron oxide or ammonium chloride, the action of which does not need to be described here.

 The coating may also include other materials or compounds usually employed to facilitate the preparation or the application of the mixture or its behavior in fire or heat, such as paper pulp, cellulose, starch, blanose, dextrin, tensio products. assets, etc., the effect of which is known and need not be described here.

A first preferred composition by weight of the coating according to the invention is as follows, in the dry state
organic binder: about 20 to 98%
mineral load in grains and / or fibers and flame retardants: about 0 to 50%
inorganic compounds providing molecules of water of crystallization
about 2 to 80%
other constituents ,. paper pulp and / or cellulose, surfactants, etc.: about 0 to 20%.

Another preferred composition by weight of the coating according to the invention is as follows, in the dry state
- - organic binder: approximately 0.5 to 20%,
- mineral filler in grains and / or fibers, and flame retardants: more than 50%
- inorganic compounds providing molecules of water of crystallization: approximately 2- to 30%,
- other constituents: pulp, and / or cellulose, surfactants: approximately 0 to 20%.

 The fact of using as a binder a compound soluble in water or capable of forming a dispersion in water allows very easy use of the coating according to the invention corresponding to one or the other of these two weight compositions favorite.

 This coating can thus be supplied in the form of a ready-to-use mixture, containing an excess of water and available in closed boxes or containers. The application can be done manually, or by mechanical or pneumatic projection.

 The coating can also be supplied in the form of a dry mixture capable of being easily sprayed, for example pneumatically, after humidification at a suitable humidity level.

 According to another variant of the invention, the coating is in the form of insulating panels essentially comprising mineral fibers, for example in the form of basalt wool, rock wool, glass or slag, ceramic wool or their mixtures, coated in an organic binder which ensures the connection between the fibers an inorganic compound providing molecules of water of crystallization.

 In a first embodiment, the incrganlque-placed shell providing molecules of water of crystallization is regularly distributed in the thickness of the panels, which are commercial panels, for example basalt wool insulating panels manufactured and marketed. under the ISOVER brand with a usual thickness between 40 and 100 mm.

The Applicant has thus carried out the following test, it has found that a sample, having a volume of 1 dm3 and weighing approximately 110 g, of such a panel is capable of absorbing approximately 730 g of water or of a comparable liquid. The Applicant took a 50g sample of such a panel and made it absorb, like a sponge, or by suction and / or pressure, 350g of an aqueous solution of sodium phosphate prepared by dissolving 50g of phosphate. trisodium crystallized in a liter of water, There is therefore approximately 17.5g of phosphate in the 350g of solution absorbed by the panel sample, which therefore weighs, after drying in an oven at 450C to remove the water from the solution, 50 + 17.5 = 67.5 g, and which thus contains 17.5 / 67.5 = 25.9 t by weight of crystallized trisodium phosphate. The latter containing 54.6% by weight of water of crystallization, the panel sample therefore comprises 25.9 x 54.6 = 14.14% by weight of water of crystallization uniformly distributed. The density of the panel sample, which was about 0,
It before the test, rose to about 0.16 after drying, which proves that the panel sample has practically retained its initial thermal (and sound) insulation properties.

 The Applicant has found that the panel sample thus prepared has an improved fire resistance of at least 30 t compared to that of the initial panel, this fire resistance being measured for example by the time necessary for, during exposure of the panel to a heat source, the temperature behind the panel reaches a predetermined value.

 To avoid the surface inflorescences of trisodium phosphate due to its migration to the surface with the solution water during drying, it is advantageous to add to the solution a reagent intended to precipitate the phosphate in the mass of the panel sample, for example latex, silicate, boric acid, sodium metaphosphate, etc.

 The above results are of course a function of the open porosity of the sheet of fibers, therefore of the nature of the fibers, the nature of the binder, the compactness of the sheet, as well as the nature of the compound providing molecules of water of crystallization.

 In another embodiment, a commercial panel is coated on at least one of its main faces with a coating containing at least one inorganic compound providing molecules of water of crystallization and an organic binder.

 A panel, such as a commercial ISOVER panel, can thus be coated with a layer a few millimeters thick with a coating comprising, for example, approximately 60% by weight of polyvinyl acetate, approximately 30% by weight of mineral, grain and / or fiber1 and flame retardant filler, approximately 10% by weight of a compound providing molecules of water of crystallization, such as crystallized trisodium phosphate.

 It is of course possible to provide such a coating on both sides of the same commercial panel, or such a coating sandwiched between two commercial panels, or to combine in any way panels impregnated with a compound providing molecules of water of crystallization, ordinary commercial panels and one or more layers of a coating of the above type.

A person qualified in this field will understand
It is easy to adapt the coating according to the invention to the nature of the support to which it is to be applied, but also to the local climatic and / or physical or chemical conditions to which it will be subjected.

 Thus, the nature of the binder will be different depending on whether the coating is placed on a concrete wall, a metal wall, plastic parts (sheaths of electric cables, piping), etc.

 Similarly, in a hot and humid area or enclosure, provision may be made to incorporate a fungicide into the coating to prevent the development of. mushrooms.

 If a coating which remains flexible for a long time is desired, latex which does not polymerize as long as it contains water can be used as a binder.

When such coatings are exposed to heat or fire, they behave as follows
the temperature of these coatings, measured within the latter, instead of increasing according to a continuously increasing curve as might be expected, remains constant for a period generally reaching several hours at a temperature of between approximately 80 and 2000C. This result gives the coatings according to the invention extremely advantageous fire and heat protection properties.

 The aforementioned temperature level can in no way be explained by the thermal insulation provided by the components of the coating. According to the opinion of the applicant, this temperature level is explained by the presence within the coating of an appreciable amount of water of crystallization.

 Indeed, the release of this water of crystallization requires a calorific contribution corresponding to the binding energy of the water molecules, and 540 kcal. per kg to transform this free water into vapor.

In addition, the water released in the form of vapor humidifies the atmosphere, which is favorable for extinguishing the fire.

 The temperature level at which this release of water takes place remains until all the water of crystallization has been vaporized. The duration of this plateau is therefore proportional to the proportion of water of crystallization of the coating.

 Of course, the invention is not limited to the exemplary embodiments described above, and many modifications and modifications can be made to these without departing from the scope of the invention.

 Thus, it is possible to incorporate into the coating according to the invention a mineral binder, such as cement, a phosphate binder, silicate, clay and their mixtures in addition to the organic binder, to increase the mechanical strength of this coating.

 The use has also been described as a binder of organic compounds which are soluble in water or capable of forming a dispersion in water. It is possible to replace the water with another liquid as soon as a ready-to-use coating is obtained, the characteristics of which contain or are acceptable for the intended conditions of application and use.

 In the case of formable coverings, these can also be projected or shaped in molds in order to obtain prefabricated elements having the required shape and which will be removed from the mold after setting and / or drying.

 In the case of coatings in the form of panels, the inorganic compound providing molecules of water of crystallization can be added after the manufacture of the panel, for example as described above, or during the manufacture of the panel in the form of grains or in the form of a more or less concentrated solution.

Claims (13)

 1. Coating to protect constructions, in particular against fire and heat, comprising a mineral filler in grains and / or fibers coated in an organic binder, characterized in that it comprises at least one inorganic compound providing the coating with molecules water of crystallization.  2. Coating according to claim 1, characterized in that the mineral filler in grains and / or fibers comprises materials such as silicates or phosphates of aluminum, calcium, magnesium or their compounds, for example, chalk, talc , clay, kaolin, mica, silica, colloidal silica, alumina, wollastonite, perlite, vermiculite, silico-aluminous or silico-magnesian compounds, magnesia, and mixtures thereof.  3. Coating according to one of claims 1 or 2, characterized in that the organic binder comprises at least one organic compound soluble in water or capable of forming a dispersion in water.  4. Coating according to claim 3, characterized in that said organic compound is chosen from homopolymers and copolymers of butadiene styrene or vinyl acetate, esters of acrylic acid, nylon, latex, adhesives vinyl or phenolic, urea-based adhesives, urea-formaldehyde or phenolformol adhesives, epoxy or polyurethane systems and their mixtures.  5. Coating according to one of claims 1 to 4, characterized in that the inorganic compound providing the coating with molecules of water of crystallization comprises at least one compound chosen from hydrated alumina, hydrated caustic soda, carbonate sodium decahydrate (Na2C03.10H20) r magnesium carbonate trihydrate (Mg CO3 3H20), magnesium nitrate hexahydrate (Mg (NO3) z .6H2 0, aluminum and potassium sulfate dodecahydrate (AIK (SO4) 2 .  2H20), aluminum sulphate octodecahydrate (A12 (SO4) 3 1 20), magnesium sulphate heptahydrate (MgSO4. 7H2 O), hydrated alums, in particular potassium and ammonium, trisodium phosphate dodecahydrate (Na3 .PO4 12H2O) the hydrated alkaline and alkaline earth phosphates, sodium silicate pentahydrate (Na2 SiO3 .5H2 0), sodium metasilicate, sodium tetraborate decahydrate (Na2 B4 O7 .10H2 O), and their mixtures.  6. Coating according to one of claims 1 to 5, characterized in that it comprises at least one flame retardant compound such as antimony oxide, boron oxide or ammonium chloride.  7. Coating according to one of claims å 6 characterized in that it comprises an inorganic binder such as cement, a phosphate binder, silicate, clay and their mixtures.  8. Coating according to one of claims 1 to 7, characterized in that it comprises other products such as pulp, cellulose, blanose, dextrin, starch and their mixtures.  9. Coating according to one of claims å to 8, characterized in that it has the following composition by weight, in the dry state  - organic binder: around 20 to 98%  - mineral filler in grains and / or fibers and flame retardants: approximately 0 to 50%  - inorganic compounds providing molecules  water of crystallization: about 2 to 80%  - other constituents, paper pulp and / or cellulose, surfactants: about 0 to 20%.  10. Coating according to one of claims 1 to 8, characterized in that it has the following composition, in the dry state  - organic binder: about 0.5% to 20%,  - mineral filler in grains and / or fibers, and flame retardants: more than 50%,  - inorganic compounds providing molecules of water of crystallization: approximately 2 to 30%,  - other constituents: paper pulp, and / or cellulose, surfactants: approximately 0 to 20%.  11. Coating according to one of claims 1 to 8, characterized in that it is in the form of insulating panels essentially comprising mineral fibers, for example in the form of basalt wool, rock wool, glass or slag , ceramic wool or their mixtures, coated in an organic binder which ensures the connection between the fibers, and an inorganic compound providing molecules of water of crystallization.  12. Coating according to claim 11, characterized in that the Inorganic compound providing molecules of water of crystallization, is regularly distributed in the thickness of the panels.  13. Coating according to one of claims 11 or 12, characterized in that each panel is coated, on at least one of its main faces, with a coating containing at least one inorganic compound providing water molecules of crystallization and an organic binder.