Barrier Coating Compositions

Abstract

The present invention relates to a composition comprising mineral or vegetable wool flakes, a powdered mineral binder and a water repellent. It further relates to a method for obtaining an insulation coating and to a building element comprising a substrate coated on one surface thereof with an insulation coating.

Description

[Technical field]

[0001] The present invention relates to the construction field, and more particularly to obtaining coatings with good thermal barrier properties. [Background technology]

[0002] It is known to thermally insulate buildings from the outside by placing panels of insulating material, such as mineral wool or polystyrene panels, on the outer walls of the building. This technique allows saving space for the occupants compared to interior insulation and allows for improved thermal insulation due to the absence of thermal bridges. Different building systems are used for this purpose. Mention may be made in particular of those made of ventilated façade systems, in which the facing plates are held by a frame at a certain distance from the insulation, thereby creating an air gap, or external insulation systems (ITE or ETICS), in which the reinforcement and the finishing plaster are placed in direct contact with the insulation. In these different techniques, the insulation panels are attached to the wall to be insulated, either by means of mechanical fasteners or by means of adhesives.

[0003] However, these techniques are complex and require significant installation time, especially for fastening the insulation and facing plates, cutting the panels on-site generates a lot of waste, and poor bonding between panels can lead to reduced thermal insulation performance. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the invention is to propose a building technique, and a composition suitable for this technique, which makes it possible to achieve a more effective thermal insulation of the facade while being simpler and faster to implement. [Means for solving the problem]

[0005] To this end, the invention relates to a composition comprising mineral or vegetable wool flakes, a powdered mineral binder, and a water repellent, the composition generally being dry, i.e. consisting essentially of a powder mixture.

[0006] The present invention also relates to a method for obtaining a barrier (insulating) coating on or against a substrate, comprising mixing such a composition with water and depositing the resulting mixture on or against said substrate.

[0007] Finally, an object of the present invention is a building element comprising a substrate coated on one of its faces with a barrier coating comprising mineral or vegetable wool flakes bound together by a hardened mineral binder and a water repellent, such a barrier coating being preferably obtained or obtainable by the method according to the invention.

[0008] The use of the composition according to the invention for depositing a barrier coating, in particular by spraying, makes it possible to overcome the aforementioned drawbacks. Surprisingly, the invention also ensures good adhesion of the barrier coating to walls (in particular, but not only to concrete walls) due to reduced carbon impact and good thermal barrier properties, ensures good cohesion of the coating, even for the large thicknesses generally required by the intended barrier performance, ensures good resistance to environmental and aging degradation, and allows good mechanical properties, in particular in compression.

[0009] After mixing the composition with water and hardening the mineral binder, the resulting coating comprises flakes of mineral wool or vegetable wool bound together by the hardened mineral binder. The mineral binder powder present in the composition becomes pasty after being mixed with water and before hardening. Thus, the term "binder" covers both the powder binder present in the composition and the hardened final binder in the final coating. The following details apply to both the composition and the final coating.

[0010] The mineral wool is preferably selected from glass wool, slag wool and stone wool. The mineral wool fibers preferably have a chemical composition comprising 30-75% by weight SiO2, 5-40% CaO+MgO, 0-20% Na2O+K2O, 0-30% Al2O3 and 0-15% Fe2O3.

[0011] The use of glass wool generally makes it possible to achieve better heat insulation performance, in particular by virtue of its relatively low density.

[0012] Glass wool is generally formed by electrical or flame-based melting of a mixture of powdered raw materials and cullet (recycled glass), followed by drawing, especially by internal centrifugation in a fiberizing spinner. The glass wool fibers preferably have a chemical composition comprising 50-75% by weight SiO2, 12-20% by weight Na2O+K2O, 5-20% by weight CaO+MgO, 0-8% by weight Al2O3, especially 0-3% by weight Al2O3, and 2-10% by weight B2O3.

[0013] Stone wool and slag wool, for their part, are generally formed by melting raw materials in the form of blocks or briquettes, or by melting powder raw materials by electric heat or immersed burners, and then drawing by external centrifugation with multiple rotors. Stone wool fibers preferably have a chemical composition including 30-50% SiO2, 10-26% Al2O3, 15-40% CaO+MgO, 0-5% Na2O+K2O, and 3-15% Fe2O3. Slag wool fibers preferably have a chemical composition including 30-45% SiO2, 5-18% Al2O3, 30-60% CaO+MgO, and 0-3% Na2O+K2O.

[0014] Mineral wool generally consists of woven glass fibers. As a rule, the mineral wool used does not contain organic binders. However, if the flakes come from recycled waste from construction sites or factories, such as obtained by crushing mineral wool panels, they may contain some organic binders. The flakes may be blown wool flakes, which usually do not contain organic binders, but otherwise may contain organic additives, such as silicone-based organic additives or antistatic agents. These additives are sprayed onto the mineral wool, especially during fiberization.

[0015] The vegetable wool comprises vegetable fibres, which are preferably selected from the group consisting of lignocellulosic fibres and cotton fibres. The lignocellulosic fibres are preferably selected from wood fibres, hemp fibres, flax fibres, sisal fibres, cotton fibres, jute fibres, coconut fibres, raffia fibres, abaca fibres, cereal straw, rice straw and mixtures thereof.

[0016] Flakes are understood to mean pieces formed of aggregates (or clusters) of intertwined fibers having a certain size or dimension. It is essential that the compositions and coatings contain fibers in the form of flakes, and not in the form of dispersed individual fibers or in the form of fibers arranged in layers, lattices, woven or nonwoven fabrics, so that good thermal insulation properties can be achieved. The coatings are therefore different from fiber-reinforced plasters or mortars, which do not have insulation properties.

[0017] The mineral or vegetable wool flakes in the composition and / or coating preferably have a size of 1-10 cm, in particular 2-8 cm, or even 3-7 cm. Flakes of too small a size lead to a coating that is relatively dense, which therefore has a relatively low thermal barrier. Obtaining the flakes and adjusting their size can be done in particular by machine. The flakes can be relatively large in the composition, if the spraying machine can reduce their size before spraying.

[0018] The powdered mineral binder is preferably a hydraulic binder.

[0019] The hydraulic binder is preferably selected from the group consisting of Portland cement, belite cement, aluminous cement, sulfoaluminate cement, pozzolana blend cement, slag, fly ash, metakaolin, hydraulic lime, calcium sulfate source, and mixtures of two or more of these hydraulic binders. The calcium sulfate source is in particular selected from gypsum, anhydrite, hemihydrate, and mixtures thereof.

[0020] The binder may in particular consist of Portland cement, in particular of type CEM I or CEM II.

[0021] According to another embodiment, the binder comprises (in particular consists of) a mixture of Portland cement and a calcium sulfate source. The presence of the calcium sulfate source makes it possible in particular to improve the fire resistance and to accelerate the setting of the binder. Its carbon impact is also reduced compared to Portland cement. The total proportion of the calcium sulfate source in the binder is preferably between 2 and 20% by weight, in particular between 5 and 15% by weight.

[0022] According to another embodiment, the binder comprises (in particular consists of) a mixture of sulfoaluminate cement and a calcium sulfate source, and preferably comprises a setting accelerator, for example a lithium salt. The total proportion of calcium sulfate source in the binder is preferably 2-20% by weight, in particular 5-15% by weight.

[0023] According to yet another embodiment, the binder comprises (or consists of) a mixture of Portland cement, aluminate cement, and a calcium sulfate source. The binder may also contain a setting accelerator, for example a lithium salt. Such a binder allows for a more rapid hardening. In this embodiment, the weight ratio of the components in the binder is preferably as follows: 65-90% Portland cement, 5-20% aluminate cement, and 2-15% calcium sulfate source.

[0024] Generally, the presence of Portland cement makes it possible to achieve good mechanical performance, especially in terms of compressive strength, and also to achieve high pH values, which have been shown to increase the efficiency of water repellents. The addition of a lime source to the aforementioned binders is also beneficial in this respect.

[0025] The binder may also consist of a calcium sulfate source, making it possible to obtain good fire resistance, but at the expense of mechanical and thermal insulation properties.

[0026] Alternatively, the mineral binder may be a clay binder.

[0027] The water repellent is essential to give the coating good resistance to aging, especially when the coating is placed on the exterior surface of a building: its presence makes it possible to suppress undesirable interactions between the binder, which is highly alkaline, and the mineral wool fibers, which are sensitive to alkaline media.

[0028] Particularly preferably, the water repellent comprises (or consists of) organosilicon compounds, in particular comprising monomeric, dimeric, oligomeric or polymeric groups of silanes and / or siloxanes.

[0029] Such water repellents have proven to be much more effective than other known water repellents, such as sodium, potassium or calcium fatty acid salts, such as calcium stearate or sodium oleate.

[0030] The organosilicon compound is preferably selected from: organosilanes, such as tetraorganosilanes of formula SiR4, such as tetraalkylsilanes, organosiloxanes, such as tetraorganosiloxanes of formula Si(OR)4, such as tetraalkoxysilanes, such as tetramethoxysilane and tetraethoxysilane, - organoorganoxysilanes, in particular of the formula SiR n (OR') 4-n (n=1 to 3), such as alkylalkoxysilanes, in particular isooctyltriethoxysilane, n-octyltriethoxysilane, or hexadecyltriethoxysilane; - organosilanols, in particular of the formula SiR n (OH) 4-n Things - oligosilanes and polysilanes, - oligosiloxanes and polysiloxanes (also known as silicone resins, for example methylsilicones, ethylsilicones, phenylsilicones or H-silicone resins), in particular those of the general formula Ra H b Si(OR') c (OH) d O (4-a-b-c-d) / 2 Contains at least one unit of (a=0-3, b=0-1, c=0-3, d=0-3 and a+b+c+d≦3.5). wherein in the above formula, the radicals R are identical or different and represent branched or unbranched alkyl radicals having 1 to 22 carbon atoms, cycloalkyl radicals having 3 to 10 carbon atoms, alkylene radicals having 2 to 4 carbon atoms, or aryl, aralkyl, alkylaryl radicals having 6 to 18 carbon atoms; the radicals R' are identical or different alkylene and alkoxyalkylene radicals, preferably methyl and ethyl, each having 1 to 4 carbon atoms; and the radicals R and R' can also be substituted by halogens such as Cl, by ethers, thioethers, esters, amides, nitriles, hydroxyls, amines, carboxyls, sulfonic acids, carboxylic anhydrides and carbonyl groups.

[0031] The water repellent is preferably in powder form. It includes, for example, organosilicon compounds and inorganic or organic solid carriers. Possible inorganic carriers are, for example, based on silica (such as precipitated silica or fumed silica), carbonates or talc. They are preferably porous and have a BET surface area of ​​preferably at least 50 m. 2 / g, or even at least 100m 2 / g.

[0032] The water repellent may also be a redispersible powder. In addition to the organosilicon compound, it may contain a polymer. These polymers are based on one or more monomers selected from the group including, for example, vinyl esters (especially vinyl esters of unbranched or branched alkyl carboxylic acids having 1 to 15 carbon atoms), methacrylates and acrylates (especially (meth)acrylates of alcohols having 1 to 10 carbon atoms), methacrylic acid, acrylic acid, vinyl aromatics, olefins, dienes, and vinyl halides. The powder may also contain water-soluble protective colloids, fatty acids, and / or antiblocking agents.

[0033] Water repellents which are particularly useful in the context of the invention are sold in particular under the product names Silres® Powder A and D by the company Wacker Chemie AG.

[0034] The water repellent may be added to the composition in the form of a powder and / or may be present in the form of a coating on the surface of the mineral wool fibers.

[0035] The composition according to the present invention may contain other ingredients.

[0036] It may in particular comprise a lightweight filler chosen in particular from perlite, vermiculite, expanded glass beads, expanded polystyrene beads, cenospheres, expanded silicates, aerogels, and mixtures thereof.

[0037] The composition advantageously comprises a redispersible polymer powder. This polymer is preferably based on one or more monomers chosen from vinyl esters (especially vinyl esters of C1-C15 carboxylic acids, such as vinyl acetate), (meth)acrylates (especially of C1-C10 alcohols), vinyl aromatics, alkenes (e.g. ethylene), dienes and vinyl halides. These polymers make it possible to improve the mechanical strength of the coating without affecting its thermal barrier properties.

[0038] The composition advantageously comprises a thickener, which also makes it possible to improve the mechanical strength of the coating without affecting its thermal barrier properties and to obtain better cohesion. The thickener is preferably a cellulose ether.

[0039] The composition may also contain a surfactant, in particular to facilitate wetting of the fibers with water during the coating deposition process. An advantageous surfactant is in particular sodium dodecyl sulfate.

[0040] The composition may further include mineral or vegetable oil to reduce dust emissions, especially when the binder contains a calcium sulfate source such as gypsum.

[0041] The content by weight of mineral or vegetable wool is preferably 50-90%, in particular 55-85%, based on the total weight of mineral or vegetable wool and mineral binder, or even based on the total weight of the composition or coating. Considering the low density of the mineral or vegetable wool flakes relative to the binder, the mineral wool predominates very significantly by volume, making it possible to achieve good heat insulation properties.

[0042] The content by weight of the mineral binder is preferably 10 to 50%, particularly preferably 15 to 45%, based on the total weight of the mineral wool or vegetable wool and the mineral binder.

[0043] In the case of slag wool, the mass ratio of wool to binder is preferably 70:30 to 90:10.In the case of glass wool, the mass ratio of wool to binder is preferably 50:50 to 70:30.

[0044] The content by weight of the water repellent is preferably 0.1 to 2%, in particular 0.5 to 1.8%, or even 0.7 to 1.6%, based on the total weight of the mineral wool and the mineral binder.

[0045] Thus, the composition and / or coating preferably comprises 50-90% by weight of mineral wool or vegetable wool, 10-50% by weight of mineral binder and 0.1-2% of water repellent, based on the cumulative weight of mineral wool or vegetable wool and mineral binder.

[0046] The total content of possible additives in the composition is usually less than 40%, or even less than 30%, or even less than 20% or less than 10%, or more than 0.1% based on the total weight of mineral wool or vegetable wool and mineral binder.It is preferably less than 5% for redispersible polymer powder and thickener, and at most 2% for oil.In other words, the total weight ratio of mineral wool or vegetable wool and mineral binder in the composition or coating is preferably at least 70%, in particular at least 80%, or even at least 90%.Additives, or at least a part of them, can alternatively be added to the water used for spraying.

[0047] The inclusion levels given above apply to both the composition and the final coating.

[0048] The composition is mixed with water and the resulting mixture is then deposited on or against a substrate.

[0049] The mixture is preferably deposited by spraying. Preferably, the composition is brought to a spray nozzle (in dry form) and water is added as soon as possible to the outlet of the nozzle. A spray machine is advantageously used which is provided with a central duct through which the composition is sprayed and around which at least one orifice, in particular several orifices, are arranged through which the water is sprayed. Mixing of the composition and water then takes place at the nozzle outlet before the mixture reaches the support.

[0050] The amount of water (by weight) relative to the amount of composition is preferably 0.2-1.5, in particular 0.5-1.4, or even 0.7-1.2. The amount of water must be sufficient for the setting and hardening of the binder. It is adjusted by taking into account the fact that the mineral or vegetable wool will absorb part of the water. If too little water is added, the composition will not adhere well to the support and will peel off. As indicated above, the water may also contain additives, such as polymers or surfactants. Preferably, the water is free of adhesives.

[0051] The total flow rate of the dry matter (mineral or vegetable wool, mineral binder and optional solid additives) is preferably 1-10 kg / min, in particular 2-8 kg / min. The water flow rate is preferably 5-10 L / min. The application speed is, for example, 0.1-1 m for a coating thickness of 140 mm. 2 / min.

[0052] The support is preferably vertical. It is preferably an exterior wall of a building, and the deposition is carried out on the external surface of said exterior wall. "Exterior wall" refers to the wall that separates the inside of the dwelling from the outside. "Exterior surface" refers to the surface facing the outside of the dwelling. And the coating, thanks to its barrier properties, mechanical properties and ageing resistance, can replace the panels of insulation in ventilated facade systems and the external thermal barrier mentioned at the beginning. This wall is advantageously a wall manufactured by additive manufacturing technology (also called "3D printing"). In this case, the texturing created by this technology (in conjunction with the fact that the mortar layers are deposited one after the other) makes it possible to improve the adhesion of the coating.

[0053] The building element then has an exterior wall, coated on its external surface with an insulation coating. The element may further have a framework (wood or metal) that allows the facing to be attached and fixed while providing an air gap between the insulation coating and the facing. The facing may be of any of the following types: glass, metal, wood, PVC, ceramic, etc. Alternatively, the element may have a reinforcing plaster, typically with a reinforcing mesh, and a finishing plaster or facing directly on the insulation coating.

[0054] However, the invention is not limited to this application and the coating may also be deposited on a horizontal support, for example to seal off a ceiling from below.

[0055] The barrier coating preferably has a thickness of 30 to 300 mm. A small thickness, for example 30 mm, may be sufficient with respect to fire resistance, but will be insufficient with respect to thermal barrier properties. The thickness of the coating is therefore preferably at least 40 mm, or even at least 50 mm or 60 mm. The spraying technique described above makes it possible to achieve thicknesses of up to 240 mm in one pass. The thickness of the coating is therefore advantageously between 60 and 240 mm. Beyond this, a second pass will generally be necessary.

[0056] The density of the coating is preferably 50 to 250 kg / m 3 , preferably 60 to 200 kg / m 3 The thermal conductivity of the coating is preferably 35 to 60 mW / mK. If the mineral wool is stone wool or slag wool, its density is preferably 100 to 200 kg / m 3 and the thermal conductivity is in particular in the range of 37 to 60 mW / mK. If the mineral wool is glass wool, the density of the coating is preferably 50 to 100 kg / m 3 , especially 60-80kg / m 3 and the thermal conductivity is in particular in the range of 35 to 40 mW / mK.

[0057] The mechanical strength of the coating is excellent, particularly in the ranges of 5-20 kPa in tension, 5-60 kPa in bending (especially 40-60 kPa with slag wool or stone wool) and 20-110 kPa in compression (especially 90-110 kPa with slag wool or stone wool).

[0058] The following non-limiting examples illustrate the invention and its advantages.

[0059] The different compositions were sprayed against walls made of cinderblock, plywood, sandstone, and tiles, with or without adhesive primer. The distance between the spray gun and the wall was 100-120 cm. The sprayed thickness was 160-180 mm, reduced to 140 mm by removing the excess, then smoothed with a float. The adhesion to the different substrates proved to be very good.

[0060] Comparative Example

[0061] In this comparative example, the composition contained 80% by weight of slag wool flakes, 18% CEM I, and 2% hemihydrate cement sold by the applicant under the name Coatwool, with the addition of 0.59% cellulose ether (tylose) and 1% mineral oil. The dry matter flow rate was 8 kg / min and the water flow rate was 6 kg / min. Example 1

[0062] In Example 1, the sprayed composition was 66.7% glass blown wool flakes, 30% cement CEM I, 3.3% hemihydrate sold by the Applicant under the name Comblissimo, with the addition of 0.82% cellulose ether (Tylose) and 1% mineral oil. The blown wool contained 0.1-0.4% water repellent (silicone), 1-2% mineral oil and 0.2% antistatic agent, which were dispersed on the fibers. The dry matter flow rate was 2.5-3 kg / min and the water flow rate was 5 kg / min. Example 2

[0063] In Example 2, the sprayed composition contained 80% by weight slag wool flakes (Coatwool), 18% CEM I, and 2% hemihydrate cement, with the addition of 1% water repellent (Silres® d) and 1% mineral oil. The dry matter flow rate was 8 kg / min and the water flow rate was 5 kg / min. Example 3

[0064] In Example 3, the sprayed composition contained 66.7% slag wool flakes, 30% CEM I, and 3.3% hemihydrate cement, with the addition of 1.66% water repellent (Silres® d) and 1% mineral oil. The dry matter flow rate was 2.5 kg / min and the water flow rate was 6 kg / min.

[0065] Table 1 below shows for each example the density (MV) of the resulting coating (unit: kg / m 3 ), the thermal conductivity (λ) of the coating (unit: mW / mK), and the water absorption (W) after 1 hour and 24 hours measured according to ISO 29767 (unit: kg / m 2 ), three-point bending resistance (unit: kPa), compressive strength (unit: kPa), and tensile strength (unit: kPa).

[0066] [Table 1]

Claims

1. A composition comprising mineral wool or vegetable wool flakes, a powdered mineral binder, and a water repellent.

2. The composition of claim 1 , wherein the mineral wool is selected from glass wool, slag wool, and stone wool.

3. 3. The composition according to claim 1 or 2, wherein the mineral or vegetable wool flakes have a size of 1 to 10 cm.

4. 3. The composition according to claim 1 or 2, wherein the powdered mineral binder is a hydraulic binder, in particular selected from the group formed by portland cement, belite cement, aluminous cement, sulfoaluminate cement, pozzolana blend cement, fly ash, metakaolin, hydraulic lime and mixtures of two or more of these hydraulic binders.

5. 5. The composition of claim 4, wherein the binder comprises a mixture of Portland cement, a calcium sulfate source, and optionally an aluminate cement.

6. 3. A composition according to claim 1 or claim 2, wherein the water repellent agent comprises an organosilicon compound, in particular a silane and / or siloxane monomeric, dimeric, oligomeric or polymeric group.

7. The composition of claim 1 or claim 2, wherein the water repellent is in powder form.

8. 7. The composition of claim 6, wherein the water repellent comprises an organosilicon compound and an inorganic or organic solid carrier or is a redispersible powder.

9. The composition of claim 1 or claim 2, further comprising a redispersible polymer powder and / or a surfactant.

10. 3. The composition according to claim 1 or claim 2, comprising 50 to 90% by weight of mineral wool or vegetable wool, 10 to 50% by weight of mineral binder, and 0.1 to 2% by weight of water repellent, based on the cumulative weight of mineral wool or vegetable wool and mineral binder.

11. 10. A method for obtaining a barrier coating on or against a substrate, comprising mixing the composition of claim 1 or claim 2 with water and depositing the resulting mixture on or against the substrate.

12. 12. The method of claim 11, wherein the deposition of the mixture is performed by spraying, the composition being conveyed to a spray nozzle and the water being added as soon as possible at the outlet of the nozzle.

13. 12. The method according to claim 11, wherein the support is vertical, in particular the outer wall of a building, and the deposition is carried out on the outer surface of the wall.

14. 12. A building element comprising a substrate coated on one surface thereof with a barrier coating comprising flakes of mineral or vegetable wool bound together by a hardened mineral binder and a water repellent, said barrier coating being in particular obtainable by a method according to claim 11.

15. A building element according to claim 14, wherein the barrier coating has a thickness of from 30 to 300 mm.