FR3034109A1 - COATED TEXTILE ANTI CONDENSATION - Google Patents

Abstract

Coated textile (1) comprising at least: • a textile core (2) comprising two facing faces with respect to each other; A first coating layer (3) covering a first face of said textile core (2); said first coating layer (3) comprising at least one low emissivity material; A second coating layer (4) covering a second face of said textile core (2); and characterized in that the second coating layer (4) comprises at least one additional material capable of exothermically reacting with water contained in an environment.

Description

FIELD OF THE INVENTION The invention relates to the field of the textile industry, and more particularly to impregnated or coated textiles. It relates more particularly to a new composition of coated fabric, which allows its use in various applications, and in particular that of sun protection, transport, tents and more generally outdoor structures with advantageous properties compared to the phenomena condensation. PRIOR ART In general, a coated fabric comprises a textile core having an impregnating layer on one or the other of its faces, or both. This impregnation layer is generally made from a polymer material, typically polyvinyl chloride (PVC), to which plasticizers are added in particular. The combination of this textile core with impregnating layers gives the coated fabric advantageous properties, including a certain mechanical strength, but also a good resistance to ultraviolet radiation, which allows its use outdoors, for example as a store , cladding, or other architectural applications, or as a truck tarpaulin. Although these textiles are suitable for outdoor uses, they are subject to mold phenomena resulting in particular from the condensation of water vapor from the surrounding air. In general, dew is the condensation of water vapor in the air. As the temperature of the air increases, the partial pressure of water vapor also increases. The temperature below which the partial pressure of water vapor in the air is equal to its saturation vapor pressure corresponds to the dew point. Thus, at the end of the day, when the temperature decreases, the vapor condenses which forms droplets of water on the surface of the coated textiles.

3034109 2 In addition to negative aesthetic aspects, and possible sagging along the textile, mold phenomena are also observed, which leads to the degradation in the short or medium term of coated textiles.

Another disadvantage associated with the dew phenomenon is the formation of premature water droplets at the end of the day. Indeed, for particular meteorological conditions, dew can occur relatively early in the day, usually late afternoon. Thus, when coated textiles are used outdoors as a protection device or the like, the premature appearance of water droplets becomes constraining. Indeed, the textile-based device may no longer properly fulfill its primary function of protection device. On the other hand, when the condensation phenomenon takes place, the quantity of droplets present on the textile structure can become too great. It is thus observed in practice that these drops of water can fall on the persons present under the structure either by runoff or when these drops become too heavy. So there is currently no anti-condensation coated textiles. SUMMARY OF THE INVENTION The object of the invention is to propose a coated textile making it possible to limit the condensation phenomenon of water vapor. For this purpose, the subject of the invention is a coated textile comprising at least: a textile core comprising two facing faces with respect to each other; A first coating layer covering a first face of said textile core; said first coating layer comprising at least one low emissivity material; - A second coating layer covering a second face of said textile core. Subsequently, the term "emissivity" means the ability of a material to re-radiate the heat energy that it has absorbed during a period of exposure to a heat source such as solar radiation for example.

As a reminder, the emissivity of a body is a dimensionless quantity being equal, for a given temperature, to the ratio between the energy emitted by radiation of a body in question relative to that emitted by radiation of a body. black. The radiated energy flux for a blackbody is defined by the following Stefan-Boltzmann relationship: F = aT4 with a Boltzmann constant. The term "low emissivity materials" means materials which have an emissivity of less than 0.5. According to the invention, the coated textile is characterized in that the second coating layer comprises at least one additional material capable of reacting exothermic with water taken in its liquid state. In other words, the invention provides a coated textile for interacting with the condensation phenomenon. First, the low-emissivity material allows the coated textile to retain some of the heat energy stored during the day by limiting the phenomena of loss. Indeed, the temperature of the external environment increases during the day until reaching a maximum temperature. At the same time, the textile accumulates this heat and consequently sees its temperature increase. When the outside temperature starts to decrease, the low emissivity layer present on the textile makes it possible to conserve this heat stored for longer periods. Indeed, the low-emissivity material has properties for delaying the dissipation of heat towards the external environment. In other words, in the presence of low-emissivity material, there is rapid accumulation of heat during the day, which is then slowly restored to the outside environment. Thanks to this amount of stored heat, the temperature of the textile is generally higher than that of the external environment when it cools at the end of the day, which has the effect of delaying the phenomenon of dew, thus delaying the formation of water droplets at the inner surface of the structure formed by the textile.

When all the heat stored by the low-emissivity material has been diffused towards the outside environment, the dew phenomenon can then take place. In this sense, the textile according to the invention has, in addition, a layer of an additional material which, in contact with the steam, in the condensed state, reacts by releasing heat. The additional material has the ability to react with water according to a hydration reaction. Thus, the first water droplets are absorbed by the layer 10 comprising the additional material which releases heat. The heat generated by this reaction creates a thin blade between the coated textile and the outside air. The temperature in this thin plate is such that the phenomenon of condensation is temporarily inhibited. Indeed, the temperature of this thin blade is greater than the temperature at which the dew phenomenon occurs. Over time, there is again a phenomenon of thermal equilibrium between this thin blade and the outside air. Once the thermal equilibrium is established, the phenomenon of exothermic reaction of the additional material with the formed water droplets occurs again and again until the temperature of the external medium rises sufficiently above the temperature. Dew. Even if the amount of additional material is not sufficient to completely consume the water produced by the dew phenomenon, the amount of droplets formed during a day is, however, greatly reduced. Thus the phenomena of pouring and / or runoff, which occur for high droplet quantities, are therefore not observed or at least greatly limited. In practice, the first and second coating layers are formed from a base polymer selected from the group consisting of PVC, or other polyolefins and a combination thereof. Advantageously in practice, the base polymer of the coating layers is PVC. which confers fireproof properties as well as a better rigidity.

In practice, the additional material reacting with water is an inorganic and non-flammable material. Advantageously in practice, this additional material is chosen from the group comprising SrBr 2, LiOH, Ba (OH) 2, CoCl 2 and a combination thereof. The additional material can be incorporated into the coated textile in different ways.

A first alternative is to disperse it uniformly within the second coating layer. Indeed, the second coating layer is in contact with the face of the textile core which is oriented inside the fabric equipped structure. It is therefore the face of the textile where the phenomenon of condensation must be controlled. As the additional material is dispersed uniformly over this second coating layer, the condensation is thus more uniformly limited over the entire inner surface of the coated textile. According to a preferred embodiment, the second coating layer comprises two superimposed layers; the first layer being in contact with the second face of the textile core and the second layer comprising the additional material. In this case, the second layer comprising the additional material is the lower layer of the textile. The term "lower layer" is used here to mean the layer of the structure formed by the coated textile which is oriented towards the interior of the structure, that is to say for example the interior of a tent. This layer is therefore directly in contact with the internal air present in the volume defined by the textile envelope. As soon as the first drop of water is formed, at the dew point, the reaction with the additional material is then very fast. As the additional material is deposited on the second coating layer, it increases its reactivity with water, thus the overall efficiency of the textile.

According to another embodiment, the additional material may be microencapsulated in a polymeric matrix. These microcapsules are embedded in said second coating layer. In this case, the polymeric shell must be permeable to condensed water vapor to allow interaction between the additional material and the water. The microencapsulation ensures the compatibility and / or chemical stability of the coating material with the additional material. According to another variant, the additional material is deposited on a support.

Advantageously, this support may be glass-based beads (SiO2) on which the additional material is deposited by methods known from the state of the art. These beads coated with the additional material are subsequently introduced into the second coating layer of the coated textile. In this case, the additional material is stable in the presence of the coating layer and the absence of an envelope makes it possible to increase the reactivity of the additional material on the water since it is directly in contact with the surface and therefore with the contact with water. Another variant consists in integrating the additional material in PVC-based open-cell foams, for example with a thickness of the order of a millimeter. The additional material may also be embedded in fibers that are embedded in the coating layer and so that the material is positioned on the surface of the fabric to maximize its interaction with the surrounding air. The fibers may be based on polyester or the like. Moreover, the hydration of the additive material is a reversible reaction, and the water stored by the additive material can then be returned to the external medium in particular by heat input due to the increase in temperature during the day. . According to another embodiment, it is possible to envisage any type of integrated heat source inside the textile, such as for example electrical wires, and making it possible to trigger the dehydration reaction of the additive material. Those skilled in the art aiming at integrating additional material into the second coating layer are also conceivable.

In practice, the low-emissivity material is selected from the group of transition metals and pre-transition metals including aluminum, silver, gold and bismuth and a combination of these. this.

Advantageously, the low-emissivity material has an emissivity of less than 0.3. As for the additional material, the low-emissivity material can be integrated into the textile coated in different ways as well.

Advantageously in practice, the first coating layer comprises two superposed layers; a first layer forming the main thickness of the plaster layer and which is in contact with the first face of the textile core; and the second layer comprising said low emissivity material. In this case, the upper surface of the textile, namely the surface which is directly exposed to the light rays, incorporates said low emissivity material. This particular configuration allows the textile to store a maximum of energy from the light rays of the sun. The textile maintains itself at a temperature which decreases more slowly thanks to this accumulated energy weakly radiated. The thermal equilibrium between the surface of the textile and the external environment is more difficult to reach. The phenomenon of condensation is delayed.

According to another variant, the textile may comprise, in addition, within the first coating layer, chromatic pigments which make it possible to modify the metallic appearance and the silvery tint inherent in the low-emissivity coating conventionally obtained with the use of metal compounds.

The second coating layer may further comprise a phase change and non-flammable material. Preferably, the inorganic phase change material is selected from the group consisting of NaCl, Na 2 SO 4.

1 OH 2 O / NaCl, CaCl 2 · 6H 2 O, Na 2 SO 4.

1 OH20, CaBr2.6H2O and a combination thereof. As the temperature of the external environment decreases, heat exchange takes place between the textile and the external environment during a conventional thermal equilibrium process. The phase change material makes it possible to delay the establishment of thermal equilibrium between the textile and the external environment. Indeed, the phase-change material is comparable to a reservoir of energy, which, following a phase change, re-releases the energy stored during the day, in the form of heat, which tends to warm up the thin layer formed between the textile surface and the air fluid. Once all the heat is transferred by thermal diffusion to the outside environment, the temperature of the textile varies again with that of the external environment.

In the same way as for the low-emissivity material and the additional material, the integration of the phase-change material within the textile can be done in different ways.

Advantageously in practice, the phase-change material is all the more effective when it is integrated in this second coating layer. Thus, it intervenes directly at the level of the textile surface where the phenomenon of condensation appears. According to another variant, the phase-change material is present within each of the layers of the coated textile. Its concentration is within the textile being thus greater, the energy accumulated during the day by phase change is also greater. In this case, the establishment of thermal equilibrium in the vicinity of the dew point is slower. The phenomenon of dew is delayed or even avoided for certain weather conditions.

According to a particular embodiment, the coated textile comprises an additional protective layer, deposited on the first coating layer. Indeed, when the textile is used for outdoor applications, a protective film having properties of resistance to variable weather conditions, allows the textile 30 to increase its life. SUMMARY DESCRIPTION OF THE FIGURES The invention will be better understood on reading the description which will follow, given solely by way of example, in no way limiting, and carried out in relation to the attached FIG. 3034109 9 which is a diagrammatic cross-sectional view. coated textile according to the invention. The invention relates to a coated, anti-condensation textile comprising a layer of an additional material which reacts exothermically in contact with the condensed water vapor.

As shown in the single figure, the coated textile 1, according to the invention, is composed of three main layers 2,3,4, namely a layer forming the textile core 2 each of whose faces is coated with a coating layer 3,4. The textile core 2 is advantageously made by weaving polyester yarns of high tenacity with a titre of between 550 and 1110 decitex. In addition, the coating layers 3 and 4 are mainly based on polyvinyl chloride (PVC), which in particular gives the textile 1 flame retardant properties. Furthermore, these coating layers 3,4 give the textile 1 interesting mechanical properties for outdoor applications.

As shown in the figure, the coating layer 3 is formed by the superposition of two layers. A first layer 31 which is in contact with the textile core 1 mainly comprises the coating material, namely PVC. A second layer 32, composed mainly of a low-emissivity material, is deposited on the layer 31.

In practice, the low-emissivity coating is composed of a material selected from the group consisting of transition metals, pre-transition metals and a combination thereof. Advantageously, the coating 32 is composed solely of aluminum. The thickness of the layer 32 is between 5 and 201.1.m.

Layer 32 may be deposited by methods known to those skilled in the art such as PVD film deposition, CVD or the like.

According to a particular embodiment, the low-emissivity material is not deposited in the form of a coating but rather dispersed in the first coating layer in a uniform manner.

According to another variant and for better chemical stability of the textile, the low-emissivity material can be encapsulated by known methods and dispersed uniformly within the first coating layer. As shown in the figure, the second coating layer 32 also comprises two distinct layers 41 and 42. A first layer 41, composed mainly of a PVC-based coating, is in contact with the textile core 2 This layer may also be made from a thermoplastic polymeric material having characteristics similar to PVC, more particularly in terms of fire and flame retardancy properties. The layer 42 is a film based on an additional material that is capable of reacting with the exothermically condensed water vapor.

In practice, the layer 42 is composed of a non-flammable and inorganic material, preferably a hydrated salt. Advantageously in practice, the layer 42 essentially comprises SrBr2. with a degree of hydration between 1 and 6 H2O and AT = 35 ° C.

Thus, the layer 42 gives the textile 1 the desired anti-condensation properties. Indeed, when the first drops of condensed water vapor appear on the surface of the layer 42, the additional material reacts immediately with these drops of water exothermically, that is to say by releasing heat. From now on and as shown in FIG. 1, a thin sheet of thickness 6 is formed between the surface 42 of the textile and the external medium 5.

In addition to the particular embodiment of the invention, numerous variants can be made, such as those described below, taken alone or in combination.

It has been described a coated textile comprising mainly three layers, namely the textile core layer and two coating layers. An alternative is to uniformly disperse the additional material within the second coating layer by known methods, such as microencapsulation as described in WO 2008/153378. The additional material can also be deposited on SiO2 glass bubbles that are evenly dispersed within the second layer of textile coating.

According to another embodiment, the low-emissivity material is dispersed uniformly in the first textile coating layer by methods known from the state of the art. Another variant not shown in the figures consists in placing a protective layer on the first textile coating layer. During the use of the textile for outdoor applications, a protective film provides a longer life. In general, the presence of the protective film makes it possible to limit the degradation of the textile, such as polycarbonates or other polyfluorates.

A second variant, not shown in the figure, consists of integrating a phase change material into the textile. Preferably, it is a non-flammable and inorganic material. Preferably the inorganic phase change material is selected from the group consisting of NaCl, Na 2 SO 4 .10H 2 O / NaCl, CaCl 2. 6H 2 O, Na 2 SO 4 .10H 2 O, CaBr 2. 6H 2 O and a combination thereof.

This material may be dispersed uniformly either within the second coating layer or over the entire textile.

According to another variant, the textile further comprises, within the first coating layer, chromatic pigments which make it possible to modify the metallic appearance and the silvery tint inherent in the low-emissivity coating conventionally obtained with the use of metal compounds. These pigments are organic and / or inorganic non-flammable types. Preferably, the inorganic pigments may be in the form of powder, flake or flakes in particular.

The present invention also relates to a method of manufacturing the coated textile. It comprises in particular the following steps: - Preparation of the textile core 1; - Coating said textile core 1 on each of these faces; Layer 32 deposition / integration comprising said low emissivity material; and 15 - Deposition / integration layer 42 comprising said additional material. According to the preferred embodiment, the deposition of the coating layers, low emissivity and additional material based are performed separately by methods known to those skilled in the art, in this case, the chemical or physical deposition in phase 20 steam, or whatever. In regard to its properties, the coated textile according to the invention is particularly attractive for applications as a protective device outdoors, such as tents, tarpaulins, barnum, or cover for cars / trucks / boats.

Thus, the invention applies to all technical fields which would find it advantageous to use a coated textile with anti-condensation properties. It follows from the foregoing that the invention has many advantages and in particular: the at least partial control of the condensation phenomenon; - The reduction of mold phenomena; - The elimination of water droplet dripping on people sheltered by the textile when it is used as an outdoor protective structure; 3034109 13 - Longer service life and / or longer use. - A lower sensitivity to soiling. - A lowering of convective exchanges.

Claims (12)

REVENDICATIONS1. Coated textile (1) comprising at least: - a textile core (2) comprising two facing faces with respect to each other; a first coating layer (3) covering a first face of said textile core (2); said first coating layer (3) comprising at least one low emissivity material; a second coating layer (4) covering a second face of said textile core (2); and characterized in that the second coating layer (4) comprises at least one additional material capable of exothermically reacting with water contained in an environment. 2. Textile according to claim 1, characterized in that said additional material is an inorganic and non-flammable material. 3. Textile according to one of claims 1 or 2, characterized in that said additional material is selected from the group comprising SrBr2, LiOH, Ba (OH) 2, CoC12 and a combination thereof. 4. Textile according to one of the preceding claims, characterized in that said second coating layer (4) comprises two layers (41,42) superimposed; the first layer (41) being in contact with the second face of the textile core and the second layer (42) comprising the said additional material 5. Textile according to one of the preceding claims, characterized in that said low-emissivity material is selected from the group of transition metals and pre-transition metals including aluminum, silver, gold and silver. bismuth and a combination of these. 3034109 15 6. Textile according to one of the preceding claims, characterized in that said first coating layer comprises two superposed layers; the first layer (31) being in contact with the first face of the textile core and the second layer (32) comprising said low emissivity material. 7. Textile according to one of the preceding claims, characterized in that the second coating layer further comprises a phase change material and non-flammable. 8. Textile according to claim 7, characterized in that said inorganic phase change material selected from the group consisting of NaCl, Na2 S04. 1 OH20 / NaCl, CaCl2.61120, Na2S04.1-01-120, CaBr2.6H2O. and a combination thereof. 9. Textile according to one of the preceding claims, characterized in that the first (3) and the second coating layer (4) are formed from a base polymer selected from the group comprising PVC, polyolefins and a combination of these. 20 10. Textile according to claim 9, characterized in that said base polymer is PVC. 11. A method of manufacturing the textile according to one of claims 1 to 10 comprising the following steps: - Preparation of the core (2) textile; - Coating said textile core by coating; - Deposition / Integration layer (32) comprising said low emissivity material; and layer deposition / integration (42) comprising said additional material. 12. Use of the textile object according to one of the preceding claims, as an external protective structure. 5 10 15