COMPOSITION FOR LIQUID WATERPROOFING SYSTEMS

Description

[0001] The invention relates to the field of construction. It relates more particularly to obtaining waterproofing membranes for buildings.

[0002] The waterproofing of roofs, terraces, balconies, damp rooms or facades is essential to ensure the durability of buildings.

[0003] To achieve this, numerous waterproofing systems have been developed. These include bituminous membranes and thermoplastic or vulcanized synthetic membranes that are assembled by welding, hot-mix asphalt coatings, and systems known in the art as "liquid waterproofing systems" (LWS).

[0004] These are made of polymer resin-based materials applied in one or more layers by spraying or by application with a roller, brush, or squeegee. Different types of resins are used, in particular polyesters, acrylics, neoprene bitumens, or polyurethane resins. Highly durable and easy to apply, these systems generally allow pedestrian traffic directly after drying, eliminating the need for heavy protection.

[0005] EP 3269777 Al and EP 0326976 Al describe compositions for waterproofing membranes comprising plasticized PVB, optionally recycled, a modified bitumen and calcium carbonate.

[0006] The invention aims to propose new waterproofing membranes that are as efficient and easy to use as polyurethane resin-based membranes and that have better performance, particularly in terms of mechanical properties, water resistance and durability than the acrylic resin-based membranes currently used. Another aim of the invention is to propose waterproofing membranes with a lower carbon footprint.

[0007] For this purpose, the subject of the invention is a composition for a liquid sealing system which is an aqueous dispersion comprising water, 5 to 50% by weight of resin particles based on poly(vinyl acetal), a plasticizer, an emulsifier, 5 to 80% by weight of fillers and 0 to 20% by weight of pigments, the mass percentages being expressed on the total weight of the composition.

[0008] The invention also relates to a method for waterproofing a roof, a terrace, a balcony, a damp room or a facade comprising the application, on a substrate of said roof, terrace, balcony, damp room or facade, of such a composition to form a membrane, then the drying of said membrane to obtain a dry membrane having a thickness ranging from 0.1 to 2.0 mm.

[0009] The invention also relates to the use of a membrane obtained by applying and drying a composition according to the invention as a waterproof membrane. The application is carried out in particular on a roof, terrace, balcony, damp room or facade substrate.

[0010] The inventors were able to demonstrate that the claimed formulations exhibited very good mechanical performance, rapid drying, very low water absorption and good resistance to aging.

[0011] Preferably, the poly(vinyl acetal) based resin is poly(vinyl butyral) based, also called PVB.

[0012] Preferably, the poly(vinyl acetal)-based resin, in particular poly(vinyl butyral)-based resin, consists of poly(vinyl acetal), in particular poly(vinyl butyral).

[0013] Preferably, the resin based on poly(vinyl acetal), in particular poly(vinyl butyral), comprises residual alcohol and acetate functions. These residual functions come from the resin manufacturing process, which is generally carried out by hydrolysis of poly(vinyl acetate) into poly(vinyl alcohol) and then acetalization of the latter. As explained in more detail later in this text, the presence of alcohol functions makes it possible to crosslink the resin and improve its properties.

[0014] The polyvinyl butyral-based resin is advantageously derived from the recycling of laminated glazing. These glazings use PVB as a lamination interlayer between two sheets of glass. Using recycled materials reduces the carbon footprint of the liquid sealing system.

[0015] Preferably, the weight content of resin based on poly(vinyl acetal), in particular based on poly(vinyl butyral) in the composition is between 7 and 48%, in particular between 10 and 45%, or even between 15 and 40% and even between 20 and 35%.

[0016] The resin content by weight corresponds to the mass percentage of resin in dry extract in the composition, therefore to the weight of resin relative to the total weight of the composition. Generally speaking, the contents of the different constituents of the composition are given relative to the total weight of the composition.

[0017] The composition may further comprise particles of other resins, in particular chosen from styrene-acrylic resins, styrene-butadiene resins, acrylic resins and mixtures of two or more of these resins. In this case, the ratio between the total weight of these resin particles and the weight of poly(vinyl acetal)-based resin particles is preferably between 0.05 and 3.0, in particular between 0.1 and 2.0. According to another embodiment, the composition does not comprise particles of resins other than poly(vinyl acetal)-based resins.

[0018] The poly(vinyl acetal) resin particles (or where appropriate the other resins described above) preferably have a volume size distribution such that the d50 is between 50 and 300 nm, in particular between 100 and 250 nm. The particle size distribution is in particular determined by dynamic light diffraction.

[0019] Preferably, the weight ratio between the plasticizer content and the poly(vinyl acetal)-based resin content is between 0.1 and 1, in particular between 0.2 and 0.5.

[0020] The plasticizer is advantageously chosen from polyethylene glycol esters, adipates, sebacates, phthalates, benzoate esters and mixtures of two or more of these compounds. Examples include tri(ethylene glycol) di(2-ethylhexanoate), tri(ethylene glycol) di(2-ethylbutyrate), tri(ethylene glycol) di(n-heptanoate), tetra(ethylene glycol) di(n-heptanoate), bis(2-butoxyethyl) adipate, dibutyl sebacate, dibutyl phthalate or dioctyl phthalate.

[0021] Preferably the weight ratio between the emulsifier content and the poly(vinyl acetal) resin content is between 0.001 and 0.05, in particular between 0.005 and 0.025.

[0022] The emulsifier is advantageously chosen from ionic emulsifiers (cationic or anionic) and non-ionic emulsifiers. Anionic emulsifiers are in particular carboxylates or sulfonates. Carboxylates are for example salts of saturated or unsaturated fatty acids such as stearates, oleates and laurates, rosin salts such as for example potassium oleate. Sulfonates are for example alkyl sulfonates, aryl sulfonates, alkyl aryl sulfonates or sulfonated esters such as for example sodium dodecyl sulfate. Non-ionic emulsifiers are in particular polyoxyethylene alkylphenyl ethers.

[0023] The emulsifier is preferably anionic. Such emulsifiers allow for lower water uptake than non-ionic emulsifiers.

[0024] The glass transition temperature of the composition is preferably between 5 and 40°C, in particular between 10 and 30°C, in order to maintain good flexibility after drying, ensuring correct bridging of any cracks that may appear on the substrate. The glass transition temperature is measured in particular by differential scanning calorimetry. The glass transition temperature can be modified in particular by varying the quantity of plasticizer.

[0025] The minimum film formation temperature (generally referred to by its acronym “MFFT”) of the composition is preferably less than 30°C, in particular less than 20°C, or even less than 10°C and even less than 0°C, in order to allow film formation and coalescence of the membrane at room temperature in different climatic conditions. The minimum film formation temperature can be modified in particular by varying the quantity of plasticizer, or even by adding coalescing agents.

[0026] The total weight content of fillers is preferably between 6 and 70%, in particular between 7 and 65%, or even between 8 and 50%, or between 9 and 40% or between 10 and 25%, or even between 11 and 24%.

[0027] The fillers are advantageously of a mineral nature. The fillers are preferably chosen from calcium carbonate, clays, talc, dolomite, mica, silica sands, ground basalt and mixtures of two or more of these compounds. The fillers preferably have a particle size ranging from 0.5 to 500 µm, in particular from 1 to 200 µm, measured by laser granulometry.

[0028] The total weight content of pigments is preferably between 1 and 20%, in particular between 2 and 10%.

[0029] The pigments are preferably selected from inorganic pigments (e.g. titanium dioxide or iron oxide), organic pigments (e.g. carbon black), and mixtures of two or more of these compounds.

[0030] Preferably, the composition further comprises a crosslinking agent.

[0031] The weight ratio between the content of crosslinking agent and the content of poly(vinyl acetal)-based resin is preferably between 0.001 and 0.10, in particular between 0.002 and 0.06.

[0032] The crosslinking agent is advantageously chosen from water-soluble organometallic compounds, water-insoluble metal oxide or hydroxide particles and organic compounds reactive with hydroxyl groups.

[0033] Organic compounds reactive with hydroxyl groups are in particular polyfunctional molecules reactive with hydroxyl groups, such as for example poly(carboxylic acids), polyisocyanates or polyaldehydes. Examples include glutaraldehyde or citric acid.

[0034] Water-soluble organometallic compounds are preferably complexes of zirconium, titanium, zinc or boron. Examples of water-soluble organometallic compounds are ammonium bis(carbonato-) dihydroxy-zirconate, ammonium bis(lactato-) dihydroxytitanate, titanium lactate or titanium triethanolaminate.

[0035] More preferably, the crosslinking agent consists of water-insoluble metal oxide or hydroxide particles, in particular zinc, zirconium or aluminum oxides or hydroxides. Zinc oxides are particularly preferred. These particles preferably have a size of between 0.5 and 100 µm, in particular between 1 and 50 µm. The particle size is typically determined by laser granulometry.

[0036] The crosslinking agent allows several resin particles to be crosslinked, in particular thanks to the residual alcohol functions mentioned above. This results in slightly faster drying and, above all, lower water absorption, especially after immersion in water.

[0037] The amount of water in the composition is preferably between 10 and 70% by weight, in particular between 20 and 60% by weight, relative to the total weight of the composition.

[0038] Preferably, the composition further comprises one or more additives, notably chosen from: defoaming agents (for example of the silicone, fluoro-silicone, mineral oil, acrylic, vinyl polymer type), coalescing agents (for example of the glycol type such as propylene glycol or diethylene glycol, glycol ethers such as dipropylene glycol n-butyl ether or propylene glycol methyl ether acetate, alcohol esters such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, pyrrolidone such as N-methyl-2-pyrrolidone or N-butyl-2-pyrrolidone), rheological agents (for example of the polyurethane / polyurea, polyacrylic, polyamide, castor oil-based, or clay-based or cellulose ether type), dispersing agents (for example of the silicone, polyacrylate, polyether type), bactericidal or algicidal agents (in particular of the isothiazolinone type such as for example benzisothiazolinone or methylisothiazolinone, or halogenated type).

[0039] The total weight content of these additives is preferably between 0.1 and 10%, preferably between 0.2 and 5% relative to the total weight of the composition.

[0040] Dispersing agents are useful to help disperse fillers and pigments. As previously mentioned, coalescing agents allow the minimum film formation temperature to be adjusted if necessary.

[0041] The composition according to the invention is normally a single-component composition, that is to say that it does not require the addition of another composition before or after application.

[0042] In order to waterproof roofs, terraces, balconies, wet rooms or facades, the composition is applied to a substrate of said roofs, terraces, balconies, wet rooms or facades to form a membrane.

[0043] Application is done using a roller, brush, or spray. It can be done in several layers. In the case of wet rooms, the membrane is generally covered with tiles.

[0044] The membrane is then dried. Drying normally takes place in the air, naturally, without heating or blowing, typically lasting from a few minutes to a few hours.

[0045] The final membrane may result from the application of several successive layers. Its dry thickness is preferably between 0.1 and 2.0 mm, particularly between 0.2 and 1.5 mm.

[0046] The substrate is preferably made of cementitious material (for example concrete, mortar or plaster), but it can also be made of stone (particularly limestone), brick, terracotta, sandstone or even ceramic.

[0047] The following examples illustrate the invention in a non-limiting manner.

[0048] Several dispersions (A to E) comprising a resin, as well as plasticizers and emulsifiers were evaluated.

[0049] Dispersions A, B and C are aqueous PVB-based dispersions containing triethylene glycol bis(2-ethylhexanoate) as a plasticizer and potassium oleate as an emulsifier, marketed by Shark Solutions. Dispersion D is an aqueous polyurethane dispersion, and Dispersion E is an aqueous styrene acrylate dispersion, these dispersions being used in comparative examples.

[0050] Table 1 below indicates for each of the dispersions the percentage of dry extract, the particle size (d50), the pH, the glass transition temperature Tg, the minimum film formation temperature (MFFT) and the electrostatic charge of the particles at a pH of 7. [Tables 1] A B C D E Dry extract (%) 45,6 46,1 47,8 44,0 59,0 Particle size (nm) 179 194 174 201 142 Tg (°C) 24 24 24 -75 / 63 11 MFFT (°C) < -1 < -1 < -1 < -1 < -1 Charge (µmol / g) -75 -70 -24 -252 -219

[0051] To these aqueous dispersions were added water, fillers (filler 1: calcium carbonate, filler 2: talc), pigments (titanium dioxide), a crosslinking agent - called crosslinker - in the form of zinc oxide particles, silicone-type defoaming agents, a polyacrylic-type dispersing agent, a polyurethane-type rheological agent, as well as a coalescing agent (propylene glycol).

[0052] Tables 2 and 3 below present the compositions tested, the contents being expressed in percent relative to the total weight of the composition. Examples 1 to 7 are examples according to the invention, while Examples C1 and C2 are comparative examples. [Tableaux2] 1 2 3 4 5 Disp. A 71,2 68,4 - - - Disp. B - - 71,2 68,8 - Disp. C - - - - 71,2 Water added 7,8 8,6 7,8 8,3 7,8 Defoamer 0,8 0,8 0,8 0,8 0,8 Dispersing 0,5 0,5 0,5 0,5 0,5 Pigments 3,7 4,0 3,7 4,0 3,7 Charge 1 11,6 12,6 11,6 12,7 11,6 Charge 2 2,9 3,1 2,9 3,2 2,9 Crosslinker 0,9 1,0 0,9 1,0 0,9 Rheology agent 0,3 0,6 0,5 0,4 0,5 Coalescing agent 0,3 0,3 0,3 0,2 0,3 Resin content 24,7 23,7 24,1 24,9 25,9 Plasticizer content 7,5 7,2 7,3 7,5 7,8 Dry extract 53,6 54,1 53,8 54,6 55,2 [Tables 3] 6 7 C1 C2 Disp. A 71,5 - - - Disp. B - 71,5 - - Disp. D - - 71,8 - Disp. E - - - 71,8 Water added 7,8 7,8 7,4 7,4 Defoamer 0,8 0,8 0,8 0,8 Dispersing 0,5 0,5 0,5 0,5 Pigments 3,8 3,8 3,7 3,7 Charge 1 12,0 12,0 11,6 11,6 Charge 2 3,0 3,0 2,9 3,2 Crosslinker - - 0,9 0,9 Rheology agent 0,4 0,4 0,3 0,3 Coalescing agent 0,2 0,2 0,1 0,1 Resin content 24,8 25,1 31,6 42,4 Plasticizer content 7,5 7,6 0 0 Dry extract 51,8 52,2 52,4 63,2

[0053] Membranes with a dry thickness of 0.3 to 0.4 mm were then obtained after applying a wet film with a thickness of 1 mm and drying for 7 days at 23°C and 50% relative humidity.

[0054] Tables 4 and 5 below indicate for each of the examples, the drying time of a wet film 1 mm thick (determined using a device called a “BK drying recorder”), the tensile strength (in MPa) and the elongation at break (in %) (determined using a tensile bench at a speed of 50 mm / min at 23°C and at 60°C), the water absorption after 1 and 7 days (in %) and the loss of mass after 7 days in water.

[0055] The water absorption A after 1 or 7 days is calculated from the mass M1 of the film after 1 or 7 days of immersion in water and the mass M2 of the film immersed in water for 1 or 7 days and then dried at 50°C for 10 hours, according to the following formula: A = 100*(M1-M2) / M2.

[0056] Tensile strength and elongation were also measured after immersion in water for 7 days, and after aging under UV radiation (7 days at 110 W / m 2 < ). The stickiness after treatment at 60°C was further evaluated qualitatively. [Table] 4 1 2 3 4 5 Drying (min) 100 100 100 95 100 Tensile strength 23°C (MPa) 9,9 10,1 10,0 8,7 11,0 Elongation 23°C (%) 450 520 480 490 390 Absorption 1 day (%) 12,2 14,9 13,9 14,2 27,5 Absorption 7 days (%) 7,7 10,0 9,0 8,5 23,2 Mass loss (%) 4,1 4,3 3,6 4,5 2,0 Tensile strength 60°C (MPa) 3,0 3,5 3,4 3,7 - Elongation 60°C (%) >1300 1210 >1300 >1300 - Tights 60°C No No No No No Tensile strength after immersion (MPa) 5,8 5,3 5,5 5,3 3,5 Elongation after immersion (%) 710 710 700 700 740 Tensile strength after UV (MPa) 13,6 12,0 12,9 12,7 11,2 Elongation after UV (%) 460 410 420 430 290 [Tableaux5] 6 7 C1 C2 Drying (min) 110 120 100 110 Tensile strength 23°C (MPa) 11,2 9,8 8,1 2,7 Elongation 23°C (%) 560 570 1500 750 Absorption 1 day (%) 20,9 18,7 11,0 11,7 Absorption 7 days (%) 11,9 12,0 15,3 25,8 Mass loss (%) 4,7 4,2 2,9 2,0 Tights 60°C No No No Yes Tensile strength after immersion (MPa) 3,1 3,8 5,3 0,6 Elongation after immersion (%) 600 620 1680 1330 Tensile strength after UV (MPa) - - 4,8 3,0 Elongation after UV (%) - - 840 690

[0057] It can be deduced from these different results that the membranes according to the invention are generally better than membranes based on styrene-acrylic resin, particularly in terms of water absorption. The membranes according to the invention also have mechanical performances similar to those of membranes based on polyurethane, and in certain cases better performances in terms of water absorption, including for low resin contents.

[0058] The addition of a crosslinking agent reduces drying time and, above all, water absorption. Elongation is slightly reduced but remains acceptable for the intended applications. The crosslinking agent also improves mechanical performance (tensile strength and elongation) after immersion in water.

[0059] The membranes according to the invention are particularly resistant to aging, and in particular have very good mechanical properties after UV irradiation. At high temperatures, the membranes according to the invention retain good mechanical properties, and do not become sticky, unlike styrene-acrylic membranes.

Claims

1. A composition for a liquid sealing system, said composition being an aqueous dispersion comprising: water, 5 to 50% by weight of polyvinyl acetal-based resin particles, a plasticizer, an emulsifier, 5 to 80% by weight of fillers, and 0 to 20% by weight of pigments, percentages by weight being given relative to the total weight of the composition.

2. The composition according to the preceding claim, wherein the polyvinyl acetal-based resin is polyvinyl butyral-based.

3. The composition according to the preceding claim, wherein the polyvinyl butyral-based resin comprises residual alcohol and acetate functions.

4. The composition according to the preceding claim, wherein the polyvinyl butyral-based resin is derived from the recycling of laminated glass.

5. The composition according to one of the preceding claims, further comprising a cross-linking agent.

6. The composition according to the preceding claim, wherein the weight ratio between the cross-linking agent content and the polyvinyl acetal-based resin content is between 0.001 and 0.10, in particular between 0.002 and 0.06.

7. The composition according to one of claims 5 or 6, wherein the cross-linking agent is chosen from water-soluble organometallic compounds, water-insoluble metal oxide or hydroxide particles and organic compounds reactive towards hydroxyl groups.

8. The composition according to one of the preceding claims, wherein the weight ratio between the plasticizer content and the polyvinyl acetal-based resin content is between 0.1 and 1, in particular between 0.2 and 0.5.

9. The composition according to one of the preceding claims, wherein the weight ratio between the emulsifier content and the polyvinyl acetal-based resin content is between 0.001 and 0.05, in particular between 0.005 and 0.025.

10. The composition according to one of the preceding claims, further comprising particles of other resins, in particular selected from styrene-acrylic resins, styrenebutadiene resins, acrylic resins and mixtures of two or more of these resins.

11. The composition according to one of the preceding claims, wherein the fillers are chosen from calcium carbonate, clays, talc, dolomite, mica, silica sands, ground basalt and mixtures of two or more of these compounds.

12. The composition according to one of the preceding claims, wherein the amount of water is between 10 and 70% by weight, especially between 20 and 60% by weight.

13. A method for sealing a roof, terrace, balcony, wet room or facade, comprising applying, to a substrate of said roof, terrace, balcony, wet room or facade, a composition according to one of the preceding claims to form a membrane, then drying said membrane to obtain a dry membrane having a thickness ranging from 0.1 to 2.0 mm.

14. The method according to the preceding claim, wherein the substrate is made of cementitious material.

15. A use of a membrane obtained by applying and drying a composition according to one of claims 1 to 12 as a waterproofing membrane.