Method for manufacturing a reinforcement suitable for being embedded in a panel or slab made from a material comprising an aqueous fraction, associated reinforcement and slab

Abstract

The invention relates to a method for manufacturing a reinforcement suitable for being embedded in a panel or a slab made from 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 the protective layer, characterized in that the polymeric composition comprises a polymeric binder which is synthesized without using a surfactant, the polymeric binder being chosen from the group comprising acrylic, styrene butadiene, styrene acrylic and ethylene vinyl acetate.

Description

[0001] Description

[0002] 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.

[0003] TECHNICAL FIELD

[0004] The present invention relates to the field of glass textiles used as reinforcement in composite construction materials. It concerns in particular a method for depositing a protective layer on the surface of the glass fiber textile.

[0005] EARLIER ART

[0006] Cement panels or slabs are very widely used in the construction industry. They must be as lightweight as possible and have excellent mechanical resistance, particularly in tension and bending.

[0007] These panels consist of cement and reinforcement, often made from a fiberglass textile material. This type of reinforcement has the advantage of being inexpensive and allows the material to be strengthened in all directions, and can even provide a decorative effect.

[0008] However, glass textiles have the disadvantage of having poor resistance to alkaline environments, which leads to a degradation of their mechanical properties over time.

[0009] Glass filaments more resistant to alkalis have been developed, and other means have been implemented to address this problem.

[0010] The most common 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.

[0011] The second drawback concerns the application of PVC resin, which is done using an organic solvent in conjunction with a plasticizer. The plasticizer 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 regulations.

[0012] Furthermore, this coating does not allow complete insulation of the fiberglass reinforcement, so the moisture present in the concrete can diffuse towards the glass filaments, putting them in direct contact with an alkaline environment.

[0013] 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. They aim to increase the mechanical strength of the reinforcement before its integration into a cement panel, in order to compensate for the decrease in this mechanical strength once the reinforcement is exposed to an alkaline environment. The first solution consists of coating the reinforcement in such a way 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 fully or partially to the reinforcing textile threads using, for example, PVC or acrylic resins. The coating layer must therefore be sufficiently thick to achieve this bond strength, which can impact the cost price and potentially the flexibility of the reinforcement needed for integration into a cement panel.

[0014] The other solution involves increasing the surface roughness of the reinforcement 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 could degrade its mechanical properties.

[0015] Document W02005 / 007988 concerns a reinforcing fabric intended for integration into an alkaline resin to form a construction panel or board. The textile reinforcement is coated with PVC, acrylic, or polyvinyl alcohol (PVA) resins. This fabric consists of warp and weft yarns with different twists. According to the instructions in this document, this difference in twist improves the uniformity of the coating. The aim is to improve the mechanical properties of the panels and achieve identical mechanical properties in both the warp and weft directions. This solution has the drawback of requiring warp and weft yarns that are necessarily different, particularly in terms of their twist.

[0016] DESCRIPTION OF THE INVENTION

[0017] The invention therefore aims to provide a method for manufacturing a reinforcement for a panel or slab which overcomes the disadvantages mentioned above, and which has very good durability, particularly when integrated into a material containing an aqueous fraction.

[0018] The invention relates more particularly to a method for manufacturing a reinforcement that is suitable for embedding in a panel or slab made from a material containing an aqueous fraction, this method comprising at least:

[0019] - a manufacturing step of a structure incorporating glass filaments,

[0020] - a step of depositing a protective layer based on a polymeric composition on the surface of said structure, this polymeric composition comprising a polymeric binder, the synthesis of which is carried out without the use of a surfactant, this polymeric binder being chosen from the group comprising acrylic, styrene butadiene, styrene acrylic, ethylene vinyl acetate,

[0021] - a crosslinking step of the protective layer.

[0022] Such a manufacturing process has multiple advantages compared to conventional treatments: the absence of PVC, the absence of solvents and the absence of plasticizers.

[0023] This process helps to reduce environmental impact, by reducing or even eliminating carbon-based solvents.

[0024] The absence, or at least the negligible amount, of plasticizers helps to reduce VOC emissions throughout the product's life cycle.

[0025] Reinforcement treated with this process exhibits mechanical properties very similar to those obtained with PVC-based treatment, and ensures that at least 80% of these mechanical properties—that is, its tensile strength (in both the warp and weft directions)—are maintained over time when the reinforcement is embedded, for example, in a concrete slab. In particular, by eliminating PVC, this process avoids the release of fumes containing hydrochloric acid.

[0026] The glass filament structure is arranged in such a way that it is essentially a two-dimensional planar structure.

[0027] 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, the synthesis of which is carried out without the use of a surfactant.

[0028] In other words, the protective layer is formed by applying at least one polymeric preparation. This polymeric preparation includes a polymeric binder made up of polymer(s) synthesized without the use of an active surfactant. This polymeric preparation is aqueous in phase.

[0029] The polymeric binder is chosen so that it can be applied to the surface of glass filaments, and is compatible for adhesion to both the glass and the 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.

[0030] 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, for example, by 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 even by excitation of crosslinkable monomers under UV radiation.

[0031] The first step of the process, according to the invention, consists of creating a structure from glass filaments. This structure is two-dimensional and its shape is adapted to the geometry of the parts to be reinforced, and is, for example, substantially rectangular.

[0032] The second step in the process involves 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 dimensional stability, preventing excessive deformation of the reinforcement in its width or length and thus facilitating its installation during the manufacturing of the panel or slab. The third step in the process is a heat treatment. This step is carried out at a specific temperature and for a specific duration to evaporate the water and cross-link the monomers that make up the polymers in the polymeric binder, so that they permanently coat the reinforcement.

[0033] This process allows for the isolation of the structure containing glass filaments, thanks to the application of a protective layer to its surface. This protective layer limits the contact between the glass filaments and the aqueous fraction of the material constituting the slab or panel in which the structure is embedded.

[0034] When the material is cement, the aqueous fraction is alkaline. This process therefore limits the contact of the glass filaments with an alkaline environment and the degradation of the slab or panel's mechanical performance over time.

[0035] 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.

[0036] 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.

[0037] The thickener allows the viscosity of the bath to be adjusted 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.

[0038] 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, in the part of the reinforcement not occupied by glass filaments.

[0039] The protective layer may also contain, for example, auxiliary products including: fillers (such as graphite, calcium carbonate, silica, clays), hydrophobic agents, crosslinking agents, catalysts, antioxidants (allowing the polymeric binder to be reduced to oxidation).

[0040] 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.

[0041] The protective layer can be removed, for example, by coating or by wrapping.

[0042] Following this application step, the excess polymeric binder can be removed to ensure a homogeneous distribution of the polymeric composition on the surface of the textile reinforcement.

[0043] A drying stage for the protective layer can also be carried out. This stage may facilitate other manufacturing steps, such as a second impregnation of the textile reinforcement.

[0044] 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.

[0045] 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 between these rollers is chosen so that, as the reinforcement passes, pressure is exerted on its surface to remove excess dye bath and ensure its homogeneous distribution. This step also allows for checking the amount of dye bath remaining on the reinforcement after the wrapping step.

[0046] According to a third embodiment, this expression step is followed by a drying step, the purpose of which is to form a solid layer on the surface of the textile reinforcement, and to facilitate the following steps of the manufacturing process.

[0047] 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 results in a more extensive and uniform coating of the textile reinforcement. In this embodiment, each impregnation step is followed by a pressing step and a drying step. This embodiment has the advantage of allowing the reinforcement to be coated with several superimposed layers of polymeric binder.

[0048] The textile reinforcement comes in the form of a two-dimensional sheet.

[0049] The glass used to make the reinforcement can be in the form of individual filaments or assembled into threads or rovings.

[0050] Rovings consist of bundles of at least two filaments parallel to each other. In a roving, the filaments may optionally be bonded together using a binder.

[0051] Glass can also be in the form of threads which are made up of filaments, assembled together by twisting.

[0052] The textile reinforcement can also be a grid or a fabric.

[0053] A grid consists of two parallel layers of yarn or roving, parallel from one layer to the other, with the yarn or roving oriented lengthwise (or warp direction). These two layers are separated by a third, perpendicular layer of yarn or roving, the yarns or roving within this third layer being parallel to each other and oriented widthwise (or weft direction). The yarns or roving in each of these three layers do not intersect. In this embodiment, the yarns or roving of the grid are perfectly straight.

[0054] A fabric is obtained by interlacing warp threads oriented lengthwise with weft threads oriented widthwise. The interlacing of the warp and weft threads provides stability to the textile reinforcement in both the width and length directions.

[0055] According to another aspect of the invention, the reinforcement is made from yarns obtained by twisting filaments. These yarns have a twist rate of between 20 and 60 twists per minute (tpm), preferably between 28 and 60 tpm. 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.

[0056] In cases where the textile reinforcement is obtained from glass filament rovings, these rovings may have a fiber count of between 34 and 2400 tex, preferably between 68 and 600 tex. The number of filaments per roving may be between 100 and 5000. The filament diameter may be between 5 and 40 µm. In practice, the textile reinforcement according to the invention may have a surface mass of between 6 and 400 g / m². 2 preferably between 6 and 165 g / m 2

[0057] One application of such reinforcement is its incorporation into concrete slabs.

[0058] DETAILED DESCRIPTION OF THE INVENTION

[0059] A first detailed example (Example No. 1) of the invention is as follows. The reinforcement is made from a grid composed of glass filaments.

[0060] The warp yarns are 68 tex multifilament yarns, composed of 400 E-type glass filaments, with a twist of 20 rpm, and a silane-based sizing. The weft yarns are also 68 tex multifilament yarns, composed of 400 E-type glass filaments, with a twist of 20 rpm, and a silane-based sizing. The grid has a basis weight of 48.6 g / m². 2 4 warp threads / cm and 3.15 weft threads / cm. The amount of polymer composition deposited on the grid is 40g / m². 2The composition of the polymeric coating is given in Table 1.

[0061] Once the impregnation stage is completed, the grid is subjected to a process in an oven at a temperature between 150 and 180°C for a duration of between 8 and

[0062] 13.5 s, in order to dry the reinforcement and crosslink 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 s.

[0063] A second detailed example (Example No. 2) of the invention is as follows. The reinforcement is made from a grid composed of glass filaments.

[0064] The warp yarns are 68 tex multifilament yarns, composed of 400 E-type glass filaments, with a twist of 28 rpm, and a silane-based sizing. The weft yarns are also 68 tex multifilament yarns, composed of 400 E-type glass filaments, with a twist of 28 rpm, and a silane-based sizing. The grid has a basis weight of 41 g / m². 2 3 warp threads / cm and 3 weft threads / cm. The amount of composition deposited on the grid is 33 g / m². 2 The composition of the polymer coating is given in Table 1.

[0065] Once the impregnation stage is completed, the grid is subjected to a process in an oven at a temperature between 150 and 180°C for a duration of between 8 and

[0066] 13.5 s, in order to dry the reinforcement and crosslink 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 s.

[0067] [Table 1]

[0068] Such a manufacturing process has multiple advantages compared to the usual treatment: the absence of PVC, the absence of solvents and plasticizers.

[0069] This reduces environmental impact and VOC emissions. Using this process, the tensile strength of the reinforcement, subjected to accelerated aging testing, remains at approximately 88% of its initial values. Specifically, example 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.

[0070] Table 2: Reinforcement performance according to example 1

[0071] To obtain the results after accelerated aging, the following protocol is used. 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. Samples of grid 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, immersed consecutively in three hydrochloric acid solutions, 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 tested specimen breaks) under the following conditions:

[0072] - Traction speed: 50mm / min,

[0073] - Distance between the jaws of the dynamometer: 200mm

[0074] - Temperature: 23 ± 2 °C,

[0075] - relative humidity: 50 ± 5%.

[0076] The relative residual resistance (R) is calculated according to equation Math 1.

[0077] [Math 1]

[0078] With :

[0079] Rv = Tensile strength, after accelerated aging test (in N / 5cm) Ri = Tensile strength, in the initial state (in N / 5cm)

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 comprises a polymeric binder, the synthesis of which is carried out without the use of a surfactant, said polymeric binder being selected from the group comprising acrylic, styrene butadiene, styrene acrylic, ethylene vinyl acetate.

2. 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. 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 process 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. Reinforcement according to claim? characterized in that the grid has a surface mass between 6 and 400 g / m² 2 .

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

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