Method for manufacturing a reinforcement suitable for embedding in a panel or slab based on a material containing an aqueous fraction, reinforcement and slab together.

Abstract

A method for manufacturing a reinforcement suitable for embedding in a panel or slab based on a material comprising an aqueous fraction, comprising a step of manufacturing a structure comprising glass filaments, a step of depositing a protective layer based on a polymeric composition on the surface of said structure, and a step of crosslinking said protective layer, characterized in that said polymeric composition is surfactant-free and comprises a polymeric binder, said polymeric binder being selected from the group comprising acrylic, styrene butadiene, styrene acrylic, ethylene vinyl acetate.

Description

Title of the invention: Method for manufacturing a reinforcement adapted to be embedded in a panel or slab based on a material comprising an aqueous fraction, reinforcement and slab associated. technical field

[0001] The present invention relates to the field of glass textiles used as reinforcement in composite construction materials. It relates in particular to a method for depositing a protective layer on the surface of the glass fiber textile. Prior art

[0002] Cement panels or slabs are very widely used in the construction industry. They must have the lightest possible weight and excellent mechanical resistance, particularly in tension and bending.

[0003] These panels comprise cement and reinforcement, often based on a glass textile material. This type of reinforcement has the advantage of being inexpensive and allowing the material to be reinforced in all directions, and even, where appropriate, to provide a decorative effect.

[0004] However, glass textiles have the disadvantage of having poor resistance to alkaline environments, which leads to a degradation of their mechanical properties over time.

[0005] Glass filaments more resistant to alkalis have been developed, and other means have been implemented to overcome this problem.

[0006] The most commonly used solution is to coat the glass filaments with polyvinyl chloride (PVC). Although PVC coating is a widely used process, it has several drawbacks. The first is related to the environmental impact of PVC, which is difficult to recycle, and when PVC is incinerated, it can release fumes containing hydrochloric acid.

[0007] The second drawback concerns the application of a PVC resin, which is carried out using an organic solvent, in conjunction with the use of a plasticizer. The latter gives the PVC a certain flexibility compatible with a flexible textile reinforcement material. Plasticizers, as they age, can generate volatile organic compounds (VOCs), and they are subject to increasingly stringent environmental constraints.

[0008] Moreover, this coating does not allow complete insulation of the fiberglass reinforcement, so that the moisture present in the concrete can diffuse towards the glass filaments, putting them in direct contact with an alkaline environment.

[0009] Document WO2023 / 137259 A1 describes cement panels incorporating a coated reinforcing textile with resistance to alkaline environments. The objective of the invention is to improve the mechanical performance of cement panels. The glass reinforcement can be a grid, a fabric, or a knit. This document discloses two solutions that can be combined. The first solution consists of coating the reinforcement so that the bond strength between the warp and weft yarns is at least 1 lbf, that is, sufficient to prevent any slippage of the yarns relative to each other, particularly during the application of the coated reinforcement, but also throughout the entire service life of the cement panel. This coating can be applied totally or partially to the yarns of the reinforcing textile with, for example, PVC or acrylic resins.The coating layer must therefore be thick enough to achieve this bonding strength, which can impact the cost price, and possibly the flexibility of the reinforcement needed to integrate it into a cement panel.

[0010] The other solution consists of increasing the surface roughness of the reinforcement in order to increase its contact area with the cement matrix. This solution does not guarantee the long-term durability of the textile reinforcement's mechanical performance and requires a specific surface treatment step on the yarns or the reinforcement itself, which may degrade its mechanical properties.

[0011] Document WO2005 / 007988 relates to a reinforcing fabric intended to be integrated into an alkaline resin to form a construction panel or board. The coating of the textile reinforcement is made with PVC, acrylic, or polyvinyl alcohol (PVA) resins. This fabric consists of warp and weft yarns with different twists. This difference in twist, according to the teachings of this document, improves the uniformity of the coating. The aim is to improve the mechanical properties of the panels and to have identical mechanical properties in both the warp and weft directions. This solution has the disadvantage of using warp and weft yarns that are necessarily different, among other things, in their twist. Description of the invention

[0012] The invention therefore aims to provide a method for manufacturing a reinforcement for a panel or slab which makes it possible to remedy the disadvantages mentioned above, and which has very good durability, in particular when it is integrated into a material containing an aqueous fraction.

[0013] The invention relates more particularly to a method for manufacturing a reinforcement that is adapted to be embedded in a panel or slab made from a material containing an aqueous fraction, this method comprising at least: - a manufacturing step of a structure comprising glass filaments, - a step of depositing a protective layer based on a polymeric composition on the surface of said structure, this polymeric composition being free of surfactant and comprising a polymeric binder, this polymeric binder being selected from the group comprising acrylic, styrene butadiene, styrene acrylic, ethylene vinyl acetate, - a crosslinking step of the protective layer.

[0014] Such a manufacturing process has multiple advantages, compared to conventional treatments: the absence of PVC, the absence of solvent and the absence of plasticizer.

[0015] This process makes it possible to reduce the environmental impact, by reducing, or even eliminating, in particular carbon-based solvents.

[0016] The absence or at least the negligible quantity of plasticizer makes it possible to reduce VOC emissions throughout the product's life cycle

[0017] A reinforcement treated with such a process exhibits mechanical properties very similar to those obtained with PVC-based treatment, and ensures that at least 80% of these mechanical properties, i.e. its tensile strength (in the warp and weft directions), are maintained over time when this reinforcement is embedded, for example, in a concrete slab.

[0018] In particular, by removing the PVC, such a process makes it possible to avoid the release of fumes containing hydrochloric acid.

[0019] The glass filament structure is arranged in such a way that it is essentially a two-dimensional planar structure.

[0020] The protective layer is deposited on the surface of the structure comprising glass filaments. This protective layer comprises at least one polymeric composition, characterized in that it comprises at least one polymeric binder and is free of any surfactant.

[0021] In other words, the protective layer is formed by the application of at least one polymeric preparation. This polymeric preparation comprises a polymeric binder made up of polymer(s) whose synthesis is carried out without the use of an active surfactant. This polymeric preparation is aqueous in phase.

[0022] The polymeric binder is chosen so that it can be applied to the surface of glass filaments, and is compatible for adhesion with the glass and with the constituent material of the panel or plate. For example, it is chosen from the group that includes acrylic, styrene butadiene, styrene acrylic, or ethylene vinyl acetate.

[0023] The polymeric binder is chosen so that it can preferably crosslink without the aid of an external additive. In other words, it is chosen so as to crosslink by for example according to a polycondensation mechanism of methyloacrylamide or organic silanes, or by reaction of keto-dihydrazide and diamine, or by Schiff reaction or by reaction of carboxylates on metal ions or by excitation of crosslinkable monomers under UV radiation.

[0024] The first step of the process, according to the invention, consists of creating a structure from glass filaments. This structure is two-dimensional and of a shape adapted to the geometry of the parts to be reinforced and, for example, substantially rectangular.

[0025] The second step of the process consists of applying a protective layer to the surface of the structure containing glass filaments. In other words, this step involves completely coating the glass filaments to isolate them from the material that will cover them, at least partially, in the construction of the panel or slab. It also provides the substrate with a degree of dimensional stability, preventing excessive deformation of the reinforcement in its width or length and thus facilitating its handling during the manufacturing of the panel or slab.

[0026] The third step of the process consists of a heat treatment step. This step is carried out at a temperature and for a duration chosen in order to evaporate the water and crosslink the monomers, constituting the polymers present in the polymeric binder, and in such a way that they permanently coat the reinforcement.

[0027] According to another aspect of the invention, the polymeric binder constituting the polymeric composition is multi-phase. By "multi-phase," it is understood that the polymeric binder consists of at least two polymers. The synthesis of the polymeric binder is carried out in several successive steps, with at least one synthesis step per polymer, so that each polymer constituting the polymeric binder is distinct from the others.

[0028] According to another aspect of the invention, the protective layer, which comprises at least one polymeric composition, may also include a thickener and / or a surfactant. This means that the polymeric binder is mixed with a thickener and / or a surfactant in an aqueous medium before being deposited on the surface of the textile reinforcement. This mixture constitutes the bath in which the reinforcement structure is impregnated.

[0029] The thickener allows the viscosity of the bath to be adapted according to the nature of the reinforcement structure. The higher the viscosity of the bath, the greater the amount of polymeric binder that can be adsorbed by the reinforcement.

[0030] The surfactant helps to limit the formation of foam during the impregnation of the reinforcement structure. In particular, the surfactant prevents the formation of a polymeric binder film in the interstices of the reinforcement structure, that is to say, in the part of the reinforcement not occupied by glass filaments.

[0031] The protective layer may also contain, for example, auxiliary products including: fillers (such as, for example, graphite, calcium carbonate, silica, clays), hydrophobic agents, crosslinking agents, catalysts, antioxidants (allowing the polymeric binder to be reduced to be sensitive to oxidation).

[0032] According to another aspect of the invention, the protective layer based on a polymeric composition is obtained by impregnating the textile reinforcement with a bath containing at least the polymeric composition and water.

[0033] The protective layer can be applied, for example, by coating or by wrapping.

[0034] Following this deposition step, the excess polymeric binder can be removed in order to ensure a homogeneous distribution of the polymeric composition on the surface of the textile reinforcement.

[0035] A drying step for the protective layer can also be carried out. Such a step may make it possible to perform, and facilitate, other manufacturing steps, such as a second impregnation of the textile reinforcement.

[0036] According to an advantageous embodiment, the impregnation of the textile reinforcement is carried out by a scouring step, i.e., bringing the textile reinforcement into contact with the bath containing water and at least the polymer composition. Both the front and back faces of the textile reinforcement are in contact with the impregnation bath simultaneously.

[0037] According to a second embodiment, this wrapping step is followed by an extrusion step which consists of passing the textile reinforcement between two parallel rollers oriented perpendicular to the direction of movement of the textile. The spacing of these rollers is chosen such that, during its passage, pressure is exerted on the surface of the textile reinforcement in order to remove excess dye bath and ensure its homogeneous distribution on the surface of the textile reinforcement. This step also makes it possible to check the amount of dye bath remaining on the textile reinforcement after the wrapping step.

[0038] According to a third embodiment, this expression step is followed by a drying step, the purpose of which is to be able to form a solid layer on the surface of the textile reinforcement, and to facilitate the following steps of the manufacturing process.

[0039] According to a fourth embodiment, the application of the polymeric composition to the surface of the textile reinforcement is carried out by at least two impregnation steps. This allows for a more extensive and uniform coating of the textile reinforcement. In this embodiment, each impregnation step is followed by an expression step and a drying step. Such an embodiment has the advantage of allowing the reinforcement to be coated with several superimposed layers of polymeric binder.

[0040] The textile reinforcement is in the form of a two-dimensional sheet.

[0041] The glass used to manufacture the reinforcement can be in the form of individual filaments or assembled into threads or rovings.

[0042] The rovings consist of bundles of at least two filaments parallel to each other. In a roving, the filaments may optionally be joined together by means of a binder.

[0043] Glass can also be in the form of wires which are made up of filaments, assembled together by twisting.

[0044] The textile reinforcement can also be a grid or a fabric.

[0045] A grid consists of two parallel layers of wires or rovings, and parallel from one layer to the other, these yarns or rovings being oriented lengthwise (or warp direction). These two layers are separated by a third layer of yarns or rovings, perpendicular to the first, the yarns or rovings within this third layer are parallel to each other and oriented widthwise (or weft direction). The yarns or rovings of each of these three layers do not intersect. According to this embodiment, the yarns or rovings of the grid are perfectly straight.

[0046] A fabric is obtained by interlacing warp yarns oriented lengthwise with weft yarns oriented widthwise. The interlacing of the warp and weft yarns provides stability to the textile reinforcement in both the width and length directions.

[0047] According to another aspect of the invention, the reinforcement is made from yarns obtained by twisting filaments. These yarns have a twist of between 20 and 60 rpm, preferably between 28 and 60 rpm. These yarns have a thread count of between 34 and 544 tex, preferably between 34 and 272 tex. The number of filaments can be between 100 and 1000 per yarn. The diameter of the filaments can be between 5 and 15 µm.

[0048] In the case where the textile reinforcement is obtained from glass filament rovings, these may have a fiber count of between 34 and 2400 tex, preferably between 68 and 600 tex. The number of filaments may be between 100 and 5000 per roving. The filament diameter may be between 5 and 40 µm.

[0049] In practice, the textile reinforcement according to the invention can have a surface mass which is between 6 and 400 g / m2, preferably between 6 and 165 g / m2.

[0050] Among the applications of such reinforcement, we can mention their incorporation into concrete slabs. Detailed description of the invention

[0051] A first detailed example (Example No. 1) of the invention is as follows. The reinforcement is made from a grid composed of glass filaments.

[0052] The warp yarns are multifilament yarns of 68 tex count, composed of 400 type E glass filaments, with a twist of 20 rpm, and comprising a silane-based sizing.

[0053] The weft yarns are multifilament yarns of 68 tex count, composed of 400 type E glass filaments, with a twist of 20 rpm, and comprising a silane-based sizing.

[0054] The grid has a surface mass of 48.6 g / m2, 4 warp threads / cm and 3.15 weft threads / cm.

[0055] The amount of polymeric composition deposited on the grid is 40g / m2. The composition of the polymeric coating is given in Table 1.

[0056] Once the impregnation step is completed, the grid is subjected to a drying step in an oven at a temperature between 150 and 180°C for a duration of between 8 and 13.5 seconds, in order to dry the reinforcement and cross-link the resin. Alternatively, this step can be carried out with heated cylinders over which the textile reinforcement passes, in which case the drying time is between 10 and 20 seconds.

[0057] A second detailed example (Example No. 2) of the invention is as follows. The reinforcement is made from a grid composed of glass filaments.

[0058] The warp yarns are multifilament yarns of 68 tex count, composed of 400 E-type glass filaments, with a twist of 28 rpm, and comprising a silane-based sizing.

[0059] The weft yarns are multifilament yarns of 68 tex count, composed of 400 type E glass filaments, with a twist of 28 rpm, and comprising a silane-based sizing.

[0060] The grid has a surface mass of 41 g / m2, 3 warp threads / cm and 3 weft threads / cm.

[0061] The amount of composition deposited on the grid is 33 g / m2. The composition of the polymeric coating is given in Table 1.

[0062] Once the impregnation step is completed, the grid is subjected to a drying step in an oven at a temperature between 150 and 180°C for a duration of between 8 and 13.5 seconds, in order to dry the reinforcement and cross-link the resin. Alternatively, this step can be carried out with heated cylinders over which the textile reinforcement passes, in which case the drying time is between 10 and 20 seconds.

[0063] [Table 1] Trade name Supplier Function Example no. 1 Example no. 2 1 (Quantity in % relative to the total mass of the polymer preparation) (Quantity in % relative to the total mass of the polymer preparation) Syntran AC5917 Zschimmer & Zc hwarz Self-crosslinking multi-phase acrylic aqueous emulsion 98.6 92.6 Agitan DF999 Munzing Surfactant 1 1 Permutex RM 13 -622 Stahl Thickener 0.4 0.4 Coatosil 2287 Momentive Crosslinking and hydrophobic agent — 1 Phobotex JVA Protex Hydrophobic agent — 5

[0064] Table 1: Detailed examples of the invention

[0065] Such a manufacturing process has multiple advantages, compared to the usual treatment: the absence of PVC, the absence of solvent and plasticizer.

[0066] This helps to reduce the environmental impact and reduce VOC emissions.

[0067] By using such a process, the mechanical properties of the tensile reinforcement, subjected to an accelerated aging test, are maintained at approximately 88% of their initial values.

[0068] More specifically, example no. 1, described above, yields the results shown in Table 2 below. For comparison, the data obtained with this example are presented alongside those expected by the end user.

[0069] [Tables2] Tensile strength - weft - initial (in N / 5cm) Tensile strength - weft - after accelerated aging (in N / 5cm) Relative residual strength - weft (in %) Example No. 1 1007 890 88.3 PVC grid 800 640 80

[0070] Table 2: Performance of the reinforcement according to example 1

[0071] In order to obtain the results after accelerated aging, the protocol below is used.

[0072] A solution containing 1 g / L of NaOH, 4 g / L of KOH, and 0.5 g / L of Ca(OH)2 is prepared beforehand and then heated to 80°C. Grid samples coated with one of the formulations mentioned above are immersed in this solution at 80°C, without stirring, for 6 hours. After this time, they are removed, successively immersed in 3 solutions containing hydrochloric acid, and then dried for 24 hours at 30°C. At the end of these 24 hours, the samples are subjected to a tensile strength test (i.e. until the test specimen breaks) under the following conditions: - tensile speed: 50mm / min, - distance between jaws of the dynamometer: 200mm, - temperature: 23 ± 2 °C, - relative humidity: 50 ± 5 %.

[0073] The relative residual resistance (R) is calculated according to equation Math 1.

[0074] [Math.l] R (%) = (^)*100

[0075] With:

[0076] Rv = Tensile strength, after accelerated aging test (in N / 5cm)

[0077] Ri = Tensile strength, in the initial state (in N / 5cm)

[0078]

Claims

Demands

1. A method for manufacturing a reinforcement suitable for embedding in a panel or slab based on a material comprising an aqueous fraction, comprising a step of manufacturing a structure comprising glass filaments, a step of depositing a protective layer based on a polymeric composition on the surface of said structure, and a step of crosslinking said protective layer, characterized in that said polymeric composition is surfactant-free and comprises a polymeric binder, said polymeric binder being selected from the group comprising acrylic, styrene butadiene, styrene acrylic, ethylene vinyl acetate.

2. A manufacturing process according to claim 1 characterized in that the polymeric binder is multi-phase.

3. A manufacturing process according to any one of claims 1 to 2 characterized in that the polymeric binder is self-crosslinking according to a Schiff reaction.

4. A manufacturing process according to any one of claims 1 to 3 characterized in that the protective layer also comprises a surfactant and a thickening agent.

5. A manufacturing process according to claim 5 characterized in that the protective layer also comprises an additive selected from: fillers, hydrophobic agents, crosslinking agents, catalysts, antioxidants.

6. A manufacturing method according to any one of claims 1 to 5 characterized in that the protective layer is applied by scrimping.

7. Reinforcement obtained from the manufacturing process according to any one of claims 1 to 6 characterized in that the structure comprising glass filaments is a grid.

8. Reinforcement according to claim 7 characterized in that the glass filaments are assembled in the form of a wire, with a twist of between 20 and 60 tpm, and a count of between 34 and 544 tex.

9. Reinforcement according to claim 7 characterized in that the glass filaments are assembled in the form of roving having a count of between 34 and 2400 tex.

10. 11 Reinforcement according to claim? characterized in that the grid has a surface mass between 6 and 400 g / m2.

11. Concrete slab including reinforcement according to any one of claims 7 to 10