Decontamination coating for toxic chemical compounds

Abstract

A decontamination coating (100,100') comprises a multilayer structure including a support (1), a trapping layer (3) intended to be brought into contact with toxic chemical compounds so as to trap them, and a holding film (4) intended to maintain the shape of the support (1) in the plane and in a direction transverse to the plane, during the formation of the trapping layer (3). A manufacturing process for the decontamination coating (100,100') is also described. Figure 1

Description

Title of the invention: Decontamination coating for toxic chemical compounds. Technical field of the invention

[0001] The present invention relates to the field of surface decontamination of surfaces contaminated by toxic chemical compounds. In particular, the present invention relates to a decontamination coating designed to trap toxic chemical compounds. According to a second aspect, the present invention relates to a decontamination system comprising the decontamination coating and a dedicated packaging device. According to a third aspect, the present invention relates to a method for manufacturing said decontamination coating. The toxic compounds may be organophosphate chemical compounds, and the invention can be applied to the decontamination of environments containing organophosphate chemical compounds, for example, in certain environments such as the chemical industry, agriculture, or in sectors combating chemical gas attacks, such as those involving organophosphate-derived chemical warfare agents of types G and V.

[0002] These compounds can be included in the formulation of insecticides, pesticides or chemical warfare agents and are classically presented as water-soluble oily organic compounds which, once dispersed in the environment, have a half-life in water ranging from 5 to 80 hours, with the risk, however, that the degradation products by hydrolysis in water remain toxic for a period of 30 to 60 days. State of the art

[0003] Given their toxicity, numerous research projects have been undertaken to develop curative solutions to the threats posed by organophosphate compounds. One focus of this research is to find systems for trapping and / or degrading these compounds in order to rapidly render them inactive. These decontamination systems are generally in the form of liquids or powders used as sprays, or in the form of hydrogels that can incorporate the toxic chemical agents through natural diffusion and miscibility.

[0004] However, these decontamination systems, although effective, need to be improved to ensure good reproducibility of the decontamination phase. Indeed, application in the form of a gel, spray, or mist does not allow for optimal and homogeneous dosing of the decontaminating materials on the surfaces to be treated. Under operating conditions, the user may not be certain that the quantity of decontaminant applied is sufficient and it will tend to apply more decontaminating materials than is actually necessary. Object of the invention

[0005] Thus, one of the aims of the present invention is to overcome at least one of the aforementioned drawbacks. To this end, the present invention proposes a decontamination coating intended to trap toxic chemical compounds, such as organophosphate chemical warfare agents of type G and V, in particular by containment and sequestration, by covering a contaminated surface with the decontamination coating, the decontamination coating comprising a multilayer structure including: - a support, in particular a porous and flexible support, - a trapping layer formed on an upper surface of the support, the trapping layer being intended to come into contact with toxic chemical compounds so as to trap them, for example by adsorption and / or by a chemical degradation reaction, and - a retaining film attached to an underside of the support, opposite the upper side, the retaining film being intended to maintain the shape of the support in the plane and in a direction transverse to the plane, during the formation of the trapping layer.

[0006] Thus configured, the decontamination coating ensures ease of use and reproducible, reliable decontamination results. Thanks to the support, the active substance can be deposited under reproducible conditions and quantities, for use as a pre-prepared layer. The presentation of the active substance in a multilayer structure makes it possible to adequately cover a contaminated surface, in particular by allowing contact with the entire contaminated surface. The quantities and nature of the constituent materials are thus optimized for maximum effectiveness, notably by confining or sequestering organophoretic compounds.

[0007] The use of the decontamination coating includes a simple contact made by placing the decontamination coating on the surface to be decontaminated, whereby the said surface is depleted very quickly, or even devoid of the aforementioned contaminants.

[0008] By the phrase "the retaining film is intended to maintain the shape of the support in the plane and in a direction transverse to the plane", it is understood that the retaining film prevents deformations of the support in the plane and in a direction transverse to the plane.

[0009] According to one possibility, the retaining film is a hydrophobic film so as not to adhere to the surfaces on which the decontamination coating is disposed during its manufacture, and during handling in the phase of applying the coatings to the surfaces to be decontaminated.

[0010] The retaining film is, for example, a Teflon or silicone film. This also allows the decontamination coating to be rolled up on itself for packaging and transport on site.

[0011] According to one arrangement, the trapping layer is a hydrogel layer formed by:

[0012] - deposition of a precursor solution of the trapping layer, on the upper face of the support, and

[0013] - polymerization of the precursor solution,

[0014] the precursor solution comprising at least one protic solvent, such as water, at least one monomer comprising an (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide group, at least one crosslinking agent comprising at least two groups selected from the (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide groups, at least one photo-polymerization initiator and at least one agent selected from alkali halides, alkali phosphates, alkali sulfates and mixtures thereof.

[0015] Thus, the trapping layer resulting from the polymerization of the monomer(s) and crosslinking agent(s) defined above traps within itself a liquid phase comprising the aforementioned agent. When the liquid phase comprises water as a protic solvent, the aforementioned polymeric material can be described as a hydrogel material.

[0016] In other words, the hydrogel material is a material in the form of a gel consisting of a polymer in which an aqueous phase is retained, which classically corresponds to the polymerization medium (i.e., the medium in which polymerization took place to form the polymer constituting the hydrogel material), which has absorbed, in our case, the organophosphorus compounds. Due to the flexibility of the polymer network constituting the hydrogel, such a material is classically capable of absorbing a mass of water that can exceed 100 times the mass of the polymer structure and, in our case, at least 5 times the mass of the polymer structure.

[0017] The hydrogel layer formation step can be carried out by applying radiation that initiates photopolymerization through the action of photopolymerization initiators, also referred to here as crosslinking agents. This radiation may advantageously belong to the ultraviolet radiation range, that is, radiation with at least one wavelength in the ultraviolet range, i.e., a wavelength between 350 nm and 420 nm. The radiation intensity can be between 1000 and 10,000 W / m². The radiation source can be natural (for example, exposure to natural sunlight) or artificial, such as, for example, radiation from a UV lamp. By way of example, an artificial light source usable within the framework of the invention could be a UV lamp emitting a wavelength of 405 nm with a power of 9000 W / m2 applied towards the precursor solution deposited on the support.

[0018] The hydrogel layer constitutes a containment material for the toxic chemical agents initially present on the surface to be decontaminated. It should also be noted that, due to the reactivity of the solution with respect to organophosphate compounds, the organophosphate compounds trapped in the gel can be naturally degraded in situ.

[0019] By the term "solution", it is specified that it is a homogeneous liquid mixture of the aforementioned ingredients, which means that these are all used in such a way as to be soluble in the practical solvent of the solution.

[0020] By "protic solvent", it is specified that a polar solvent having at least one hydrogen atom capable of participating in the formation of hydrogen bonds is meant, an example of a protic solvent particularly advantageous for the invention being water, in which case the solution of the invention can be described as an aqueous solution.

[0021] The protic solvent, such as water, may be present in the precursor solution at a level of 40 to 60% by volume relative to the total volume of the solution.

[0022] By (alkyl)acrylic group, (alkyl)acrylate group or (alkyl)acrylamide group, it is specified that we mean respectively: - for the (alkyl) acrylic group, an acrylic group or an alkylacrylic group (which means that an alkyl group is present on the carbon bearing the double bond and the -CO- group); - for the (alkyl)acrylate group, an acrylate group or an alkylacrylate group (meaning that an alkyl group is present on the carbon bearing the double bond and the -CO- group); and - for the (alkyl)acrylamide group, an acrylamide group or an alkylacrylamide group (which means that an alkyl group is present on the carbon bearing the double bond and the -CO- group). An example of an (alkyl)acrylic group, (alkyl)acrylate group or (alkyl)acrylamide group is respectively a (meth)acrylic group, a (meth)acrylate group or a (meth)acrylamide group.

[0023] An example of an (alkyl)acrylic group, (alkyl)acrylate group or (alkyl)acrylamide group is respectively a (meth)acrylic group, a (meth)acrylate group or a (meth)acrylamide group.

[0024] As mentioned above, the precursor solution of the invention comprises at least one monomer comprising an (alkyl)acrylic group, an (alkyl)acrylate group or an (alkyl)acrylamide group, such a monomer being able to correspond to the following formula (I):

[0025] [Chem.l] R2 ü)

[0026] in which:

[0027] R, represents -OR' with R' representing a hydrogen atom or an alkali element (such as sodium or potassium); -OR3 with R3 representing an alkyl group, preferably comprising 1 to 4 carbon atoms (such as a methyl group, an ethyl group); or -NR4R5 with R4 and R5 representing, independently of each other, a hydrogen atom or an alkyl group, preferably comprising 1 to 4 carbon atoms (such as a methyl group, an ethyl group);

[0028] R2 represents a hydrogen atom or an alkyl group, preferably comprising 1 to 4 carbon atoms (such as a methyl group, an ethyl group).

[0029] Advantageously, the monomer(s) of the invention comprise an (alkyl)acrylamide group, such as those corresponding to the following formula (II):

[0030] [Chem.2]

[0031] in which:

[0032] R4 and R5 are as defined above;

[0033] R2 is as defined above.

[0034] In particular, it may be a monomer of formula (II), in which R2 is a hydrogen atom and R4ct R5 represent a methyl group, such a monomer corresponding to N,N'-dimethylacrylamide.

[0035] The monomer(s) may be present in the precursor solution at a level of 40 to 60% by volume relative to the total volume of the solution. For example, when the monomer is N,N'-dimethylacrylamide, it may be present at a level of 47.8% by volume relative to the total volume of the precursor solution.

[0036] The precursor solution of the invention also comprises at least one crosslinking agent comprising at least two groups selected from the groups (alkyl)acrylics, (alkyl)acrylates, (alkyl)acrylamides, which in other words means that it is a compound comprising, for example: - at least two (alkyl)acrylic groups; - at least two (alkyl)acrylate groups; - at least two (alkyl)acrylamide groups; - at least one (alkyl)acrylic group and at least one (alkyl)acrylate group; - at least one (alkyl)acrylic group and at least one group (alkyl)acrylamide; or - at least one (alkyl)acrylate group and at least one (alkyl)acrylamide group.

[0037] Advantageously, the crosslinking agent(s) are agents comprising at least two (alkyl)acrylate groups, such as those corresponding to the following formula (III):

[0038] [Chem.3] R*

[0039] in which:

[0040] R6 and R7 represent, independently of each other, a hydrogen atom or an alkyl group, for example, comprising 1 to 4 carbon atoms (for example, a methyl group, an ethyl group);

[0041] n corresponds to the number of occurrences of the pattern taken in parentheses, this number ranging from 1 to 15.

[0042] By way of example, a crosslinking agent usable in the precursor solution of the invention is an agent of formula (III), in which R6 and R7 are methyl groups, this agent thus corresponding to a polyethylene glycol di-methacrylate.

[0043] It is entirely possible to use several distinct crosslinking agents falling within the definition of formula agents (III) defined above.

[0044] It is also understood that the crosslinking agents are distinct from the monomers used in the precursor solution of the invention.

[0045] In particular, a mixture of polyethylene glycol dimethacrylate with an average molar mass of 750 g / mol may be used, corresponding to a mixture of several molecules of formula (III) defined above, with an average number of occurrences of the ethylene glycol motif of 13.2. The crosslinking agent(s) may be present in the precursor solution at a level of 1 to 5% by volume relative to the total volume of the solution.

[0046] When it comes to the aforementioned polyethylene glycol dimethacrylate mixture, this mixture may be present in the precursor solution at a level of 1.6% by volume relative to the total volume of the solution.

[0047] Finally, the precursor solution comprises at least one photopolymerization initiator (which may also be called a photoinitiator), which initiator is a compound capable of generating free radicals when subjected to appropriate radiation (for example, UV radiation between 350 and 420 nm). The radicals thus formed will react with the reactive sites of the compounds present in the solution (here, the polymerizable functions of the monomers and crosslinking agents), thereby leading to the polymerization of these compounds. This initiator or these initiators are advantageously solubilized by at least one of the constituent ingredients of the precursor solution (for example, the protic solvent).

[0048] The photo-polymerization initiator(s) that may be used in the precursor solution of the invention may be initiators from the family of aromatic ketones, such as 1-hydroxy-cyclohexylphenyl ketone (also known under the trade names IRGACURE® 184 or CPK®) or (phenylphosphoryl)bis(mesitylmethanone) (known under the name IRGACURE®819) or a mixture of these two photoinitiators.

[0049] The photopolymerization initiator(s) may be present in the precursor solution at a concentration of 1 to 15 g / L. For example, when the initiator is IRGACURE® 184, it may be present at a concentration of 11.5 g / L.

[0050] Finally, the precursor solution comprises at least one agent selected from alkali halides, alkali phosphates, alkali sulfates and mixtures thereof.

[0051] The inventors have observed that these agents contribute to neutralizing organophosphorus compounds and, in particular, type V combat organophosphorus compounds, which are compounds comprising a sulfur atom, which is connected to a phosphonate group, the aforementioned agents being able to break phosphorus-sulfur bonds to accelerate their hydrolysis.

[0052] In addition, the aforementioned agents make it possible to increase the ionic strength of the solution containing them, which makes it possible, among other things, to increase the sequestering power of organophosphorus compounds by osmotic pressure.

[0053] The agent(s) may be present in the precursor solution at a level of 1 to 30 g / L, preferably from 1 to 15 g / L.

[0054] More specifically, the agent(s) may be chosen from alkali fluorides, the alkali fluoride(s) may be present in the precursor solution at a level of 1 to 15 g / L.

[0055] A particularly effective and usable agent in the precursor solution of the invention is potassium fluoride, which can, for example, be present in the solution at a level of 11.5 g / L.

[0056] By way of example, the precursor solution of the invention may be composed exclusively of at least one protic solvent, at least one monomer comprising an (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide group, at least one crosslinking agent comprising at least two groups selected from the (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide groups, at least one photo-polymerization initiator and at least one agent selected from the alkali halides, alkali phosphates, alkali sulfates and mixtures thereof.

[0057] A precursor solution according to the invention is a solution comprising and / or consisting exclusively of the following ingredients: - water as a protic solvent; - as a monomer, N,N'-dimethylacrylamide; - as a crosslinking agent, polyethylene glycol dimethacrylate or a mixture thereof; - as a photo-polymerization initiator, 1-hydroxy-cyclohexylpheny Icetone (also known under the trade name IRGACURE® 184); - as an agent, potassium fluoride.

[0058] According to one possibility, the support is formed of at least one layer of foamed polymer. This gives the support great flexibility so that the multilayer structure is also flexible and flat, which facilitates its handling on the site to be decontaminated.

[0059] According to one arrangement, the support comprises an upper subsurface having a portion of the trapping layer impregnated into the support. This impregnation is achieved over a thickness of a few tenths of a millimeter. This impregnation is beneficial because it helps to ensure bonding between the support and the trapping layer. As will be seen later in the description of the manufacturing process, this impregnation is achieved by depositing a viscous precursor solution of the trapping layer, by simple capillary action and the effect of gravity in the pores of the support before polymerization treatment.

[0060] According to one possibility, the support consists of a single polymer.

[0061] The upper subsurface consists of a portion of the thickness of the support under the upper surface and which has a thickness of less than 1 mm.

[0062] According to one provision, the support is formed of at least one layer of polyurethane (PU) foam. The use of such a material is advantageous because it is inexpensive and its manufacture is achieved by a well-known process.

[0063] According to one possibility, the support has a thickness between 1 and 10 mm, and in particular between 2 and 7 mm, depending on the desired handling for winding the decontamination coating and the desired mechanical strength.

[0064] According to a particular embodiment, the support is a multilayer assembly comprising an upper layer and a lower adsorbent layer, the lower adsorbent layer being capable of adsorbing toxic chemical compounds. Thus, the increased thickness of this multilayer support enhances the containment capacity of the decontamination coating. Furthermore, the lower layer complements the sequestration effect obtained with the toxic compound trapping layer by adsorbing any residual toxic compounds, particularly those present in gaseous form. This lower layer is therefore capable of containing toxic compounds.

[0065] According to one possibility, the multilayer assembly comprises polyurethane foam.

[0066] According to one arrangement, the subsurface of the upper layer of the multilayer assembly is impregnated with a portion of the trapping layer.

[0067] According to one possibility, the lower adsorbent layer comprises and / or is made up of a layer of polyurethane foam impregnated with a porous adsorbent material.

[0068] According to one provision, the adsorbent material comprises and / or is made of activated carbon.

[0069] According to one possibility, the decontamination coating includes an adhesive film between the lower adsorbent layer and the upper layer. Thus, the two layers of the support are held firmly together.

[0070] According to one provision, the bonding film is formed of at least one thermo-fusible polyolefin polymer material at a temperature above 130°C. The nature of the bonding film allows for simple and efficient bonding of the lower and upper layers by applying heat to promote adhesion.

[0071] According to other features, the decontamination coating of the invention comprises one or more of the following optional features considered alone or in combination: - The retaining film is attached to the underside of the support by means of an adhesive film. - The adhesive film comprises or is made of a material derived from acrylic polymers. - The thickness of the adhesive film is less than or equal to 1 mm. - The trapping layer has a thickness of between 1 and 4 mm, and in particular between 1.5 and 3 mm. - The substrate is single-layer. - The polyurethane foam support comprises mostly open pores. - PU foam is obtained from a mixture of polyols and isocyanates. - The thickness of the impregnation by the trapping layer of the upper subsurface of the support is a few tens of nanometers. - The PU foam of the lower layer is identical to the PU foam of the upper layer in the two-layer assembly. - PU foam has a density between 15 and 40 kg / m3 so as to give the coating the necessary handling for its use and packaging in the rolled position. - The support is a two-layer assembly consisting of a top layer, an adsorbent bottom layer and an adhesive film. - The lower adsorbent layer has a thickness of between 0.5 and 3 mm. - The top layer has a thickness of between 1 and 4 mm, for example between 1 and 3 mm. - The weight of activated carbon in the lower adsorbent layer is between 50 and 500 g / m2. - The hot melt material of the bonding film is chosen from a polyester material, polyamide and / or a combination of these materials.

[0072] According to a second aspect, the invention proposes a decontamination assembly comprising the decontamination coating as previously described and a conditioning device for preserving the decontamination coating, the conditioning device being formed by a multilayer assembly comprising at least one layer of aluminium and one layer of PET (PolyEthylene Terephthalate).

[0073] Thus configured, the packaging device keeps the decontamination coating protected from light, shielding it from UV rays, hermetically sealing it to prevent moisture penetration, and preventing it from adhering to the coating to avoid damage. This ensures that the decontamination coating can be preserved for several months.

[0074] According to one possibility, the packaging device is configured to be heat-sealable. This allows the decontamination coating to be introduced and then hermetically sealed.

[0075] According to one variant, the packaging device is equipped with a hermetic ZIP closure.

[0076] According to one provision, the packaging device comprises three or four laminated layers, said layers being made of aluminium and PET.

[0077] For example, a packaging device for the decontamination assembly according to the invention comprises 12 microns of external polyester (PET), 12 microns of aluminum (central) and 75 microns of internal polyethylene.

[0078] Tests carried out with a three-layer conditioning device as described have indeed shown that this conditioning device makes it possible to keep the decontamination coating for one year without aging, and therefore without loss of its trapping properties.

[0079] According to a third aspect, the invention proposes a method for manufacturing the decontamination coating as previously described, the method comprising the following steps: a. provision of a retaining film, b. securing the underside of the support to the retaining film, c. Deposition of a precursor solution for the trapping layer onto the upper surface of the support, d. photo-polymerization of the precursor solution to obtain the trapping layer.

[0080] According to one possibility, the bonding of the lower face of the support to the retaining film is achieved by means of the adhesive film previously deposited on the retaining film.

[0081] The application of the precursor solution to the upper surface according to step c) is carried out in such a way as to generate impregnation of the precursor solution in the upper subsurface of the substrate to form, in step d), a portion of the trapping layer impregnated within the substrate. This arrangement strengthens the adhesion between the substrate and the trapping layer.

[0082] According to one possibility, the precursor solution is deposited by coating the substrate. Depending on the viscosity of the precursor solution, the solution penetrates the upper subsurface of the substrate. For example, it penetrates a few tenths of a millimeter of the substrate's thickness so as to bond the two layers, particularly for ease of use but also to allow the coating to be rolled up during a conditioning phase.

[0083] According to one provision, the photopolymerization of the precursor solution is carried out by radiation, in particular by ultraviolet radiation, that is to say, radiation having a wavelength in the ultraviolet range, i.e., a wavelength between 350 and 420 nm. The intensity of the radiation can be between 1000 and 10,000 W / m2.

[0084] According to one possibility, the process includes a step i) carried out before step b) of supplying a polyurethane foam support comprising a two-layer assembly obtained by bonding via a bonding film between an adsorbent lower layer and an upper layer.

[0085] According to one possibility, the process includes before step i) a step j) of immersing the lower layer of foamed polymer with an aqueous solution of activated carbon comprising a binder and a thickener so as to form the lower adsorbent layer after drying.

[0086] According to one possibility, step j) is renewed a second time on the lower layer impregnated with activated carbon after drying in order to increase its adsorption capacity according to the intended needs.

[0087] According to one provision, the manufacturing process includes a step e) consisting of rolling the coating onto itself, the trapping layer being in contact with the retaining film, surfaces in direct contact, for packaging purposes, in particular in the packaging device described above. Brief description of the drawings

[0088] Other aspects, objects, and advantages of the present invention will become clearer upon reading the following description of two embodiments thereof, given by way of non-limiting example and with reference to the accompanying drawings. The figures do not necessarily have to be to scale for all the elements shown in order to improve their legibility. In the remainder of the description, for the sake of simplicity, identical, similar, or equivalent elements of the different embodiments are referred to by the same numerals.

[0089] Fig. 1 illustrates a schematic view of a cross-section of a decontamination coating according to a first embodiment of the invention.

[0090] Fig. 2 illustrates a schematic view of the decontamination coating in a rolled-up position in preparation for packaging.

[0091] Figure [Fig. 3] illustrates a schematic view of a cross-section of a decontamination coating according to a second embodiment of the invention. Detailed description

[0092] In the figures and throughout the description, the same reference numerals represent identical or similar elements. Furthermore, the various elements are not drawn to scale in order to enhance the clarity of the figures. Moreover, the different embodiments and variants are not mutually exclusive and may be combined.

[0093] Unless otherwise stipulated, the term "substantially" means, in this document, "exactly or to within 10% or to within 10°".

[0094] As illustrated in [Fig. 1], the decontamination coating 100 comprises a support 1 on the upper surface 2 of which is formed a trapping layer 3 and a retaining film 4 attached to the lower surface 5 of the support 1 by means of an adhesive film 6. The support 1 comprises a layer of porous material obtained from a foamed polymer such as polyurethane foam. The support 1 is sufficiently flexible to be able to roll up on itself (see [Fig. 2]), even once attached to the trapping layer 3 and the retaining film 4, which facilitates its packaging, particularly when manufactured in the form of a continuous strip.

[0095] The trapping layer 3, intended to come into contact with toxic contaminants, is formed by coating the upper surface 2 of the support 1. The trapping layer 3 is in the form of a hydrogel obtained by photopolymerization of a precursor solution comprising: - at least one monomer comprising an (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide group, - at least one crosslinking agent comprising at least two groups selected from the following groups: (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide, - at least one photopolymerization initiator - and at least one agent selected from alkali halides, alkali phosphates, alkali sulfates and mixtures thereof, all of which are diluted in a protic solvent, such as water.

[0096] The precursor solution is deposited by coating and penetrates the upper subsurface of the porous support 1 to a depth of a few tenths of a millimeter by simple gravity, long enough to allow photopolymerization to occur. This generates the formation of a portion 7 of the trapping layer 3 impregnated in the support 1, which allows good adhesion between the latter and the trapping layer 3.

[0097] The holding film 4 is adhered to the lower face 5 of the support 1 before the coating of the precursor solution so as to complete and achieve a rigidity necessary for the support 1 to retain its shape (layer extending in a plane and having at least two parallel sides) and its flatness during the formation steps of the trapping layer 3.

[0098] Figure 3 illustrates a decontamination coating 100' according to the second embodiment of the invention. It differs from the previous one in particular in that the support 1 comprises a two-layer assembly 8, based on polyurethane foam, having an upper layer 9 on which the trapping layer 3 is formed and a lower adsorbent layer 11 bonded to the upper layer 9 by means of a film The 12 hot-melt bonding layer is a lower 11 adsorbent layer made of polyurethane foam impregnated with activated carbon. This configuration is specifically designed to improve decontamination in the presence of more volatile contaminants, or at least those capable of migrating through the thickness of the decontamination coating 100, 100'.

[0099] The invention will now be described in light of the examples below, these examples being provided only as an illustration of the invention and in no way constituting a limitation thereof.

[0100] Decontamination tests are thus carried out by the French Directorate General of Armaments (DGA) on samples 200, 200' of the two types of decontamination coating 100, 100' (without and with activated carbon) with respect to organophosphorus combat gases according to the recommendations of the AEP-65 standard (NATO standard), adapted in particular to the specificities of the samples 200, 200'.

[0101] Samples 200, 200' having a surface area of ​​5x5 cm2 and comprising a thickness between 3 and 4 mm are removed from their packaging just before carrying out the decontamination tests.

[0102] An example of preparing a precursor solution for a trapping layer 3 according to an embodiment of the invention is described below.

[0103] In a 30 ml pillbox, previously dried in an oven overnight at 90°C under dynamic vacuum and conditioned under argon, 10.4 mL of N,N'-dimethylacrylamide, 11.0 ml of distilled water, 0.35 mL of poly(ethylene glycol)dimethacrylate with an average molar mass of 750 g / mol, 0.25 g of IRGACURE®184 and 0.25 g of potassium fluoride are introduced successively.

[0104] A magnetic stir bar is introduced into the resulting medium. The medium is then purged with argon and placed under magnetic stirring until complete dissolution of the solid compounds, such as IRGACURE® 184 and potassium fluoride.

[0105] The precursor solution is deposited by coating onto the upper surface 2 of the support 1,8. Complete gelation of the precursor solution is achieved after 9 minutes of exposure to a UV lamp emitting a wavelength of 405 nm with a power of 9000 W / m2. The hydrogel thus formed makes it possible to obtain the decontamination coatings 100, 100'.

[0106] In parallel, the contaminating compounds are placed on a HDPE (High Density Polyethylene) support, having a flat surface. Once the supports are contaminated, they are placed in a hermetically sealed, temperature-controlled chamber at approximately 30°C for 90 min.

[0107] Then, the decontamination coating 100, 100' is placed on the surface of the contaminated support with the application of pressure (20g / cm2) and the assembly, kept under pressure, is placed for 1 hour in a thermo-regulated chamber at approximately 30°C.

[0108] The decontamination coating 100,100' is then placed in a solvent so as to dissolve the contaminating compounds that the decontamination coating 100,100' has trapped. The solvent solution is then analyzed by gas chromatography and / or liquid chromatography, depending on the contaminant, in order to calculate the amount of contaminant trapped in the decontamination coating 100,100'.

[0109] These tests are repeated five times for each of three toxic organophosphorus chemical compounds (compounds A, B and C) with a sample 200 of the decontamination coating 100 without activated carbon, a sample 200' of the decontamination coating 100' with activated carbon and with a decontamination layer comprising only the material of the trapping layer 3 (which will be referred to hereafter as the hydrogel coating).

[0110] The results of these tests illustrated in Table 1 below report the effectiveness of the decontamination of sample 200 with respect to the hydrogel coating alone (for the same types of material of the trapping layer) and the effectiveness of the decontamination of sample 200' with respect to the hydrogel coating alone (refer in particular to document EP3740514 for the application of the hydrogel alone). [YES] [Table 1] Coatings considered: Rate of improvement in decontamination compared to Component A; Rate of improvement in decontamination compared to Component B; Rate of improvement in decontamination compared to Component C. Sample 200 / hydrogel coating alone: ​​97.00%; 65.00%; 63.00%. Sample 2007 / hydrogel coating alone: ​​100.00%; 88.00%; 94.00%.

[0112] Decontamination tests show that decontamination coatings 100 (sample 200) and 100' (sample 200') are more effective than using a hydrogel coating alone (for example, a 97% improvement in decontamination is observed between sample 200 and the hydrogel coating alone with respect to compound A). Decontamination coating 100', which includes activated carbon, is particularly effective at decontaminating organophosphate contaminants present on smooth surfaces.

[0113] Furthermore, after one year of conditioning samples 200, 200' of decontamination coatings 100, 100' in the conditioning devices described above, the test results show the same level of decontamination. It is therefore possible to conclude that the trapping layer 3 does not undergo aging over this period under these conditioning conditions.

[0114] Thus, the present invention proposes highly effective decontamination coatings against toxic chemical compounds, in particular organosphores, which are stable over time and simple to manufacture, in particular in the form of a strip which can be cut according to the desired uses.

Claims

Demands

1. Decontamination coating (100,100') intended to trap toxic chemical compounds, by covering a contaminated surface with the decontamination coating, the decontamination coating comprising a multilayer structure including: - a support (1), - a trapping layer (3) formed on an upper face (2) of the support (1), the trapping layer (3) being intended to be brought into contact with the toxic chemical compounds so as to trap them, and - a retaining film (4) attached to an under face (5) of the support (1) opposite the upper face (2), the retaining film (4) being intended to maintain the shape of the support (1) in the plane and in a direction transverse to the plane, during the formation of the trapping layer (3).

2. Decontamination coating (100,100') according to claim 1, wherein the trapping layer (3) is a hydrogel layer formed by: - ​​deposition of a precursor solution of the trapping layer (3) on the upper face (2) of the support (1), and - polymerization of the precursor solution, the precursor solution comprising at least one protic solvent, at least one monomer comprising an (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide group, at least one crosslinking agent comprising at least two groups selected from the (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide groups, at least one photo-polymerization initiator and at least one agent selected from alkali halides, alkali phosphates, alkali sulfates and mixtures thereof.

3. Decontamination coating (100,100') according to claim 1 or 2, wherein the support (1) is formed of at least one layer of foamed polymer.

4. Decontamination coating (100,100') according to any one of claims 1 to 3, wherein the support (1) comprises an upper subsurface having a portion (7) of trapping layer (3) impregnated in the support (1).

5. Decontamination coating (100,100') according to any one of claims 1 to 4, wherein the support (1) is formed of at least one layer of polyurethane foam.

6. Decontamination coating (100') according to any one of claims 1 to 5, wherein the support (1) is a multilayer assembly (8) comprising an upper layer (9) and an adsorbent lower layer (11), the adsorbent lower layer (11) being capable of adsorbing toxic chemical compounds.

7. Decontamination coating (100') according to claim 6, wherein the lower adsorbent layer (11) comprises at least one polyurethane foam impregnated with an adsorbent porous material.

8. Decontamination coating (100') according to claim 7, wherein the porous adsorbent material comprises activated carbon.

9. Decontamination coating (100') according to any one of claims 6 to 8, which comprises a bonding film (12) between the lower adsorbent layer (11) and the upper layer (9).

10. Decontamination assembly comprising the decontamination coating (100,100') according to any one of claims 1 to 9 and a conditioning device for preserving the decontamination coating, the conditioning device being formed by a multilayer assembly comprising at least one layer of aluminium and one layer of PET (Polyethylene Terephthalate).

11. A method for manufacturing the decontamination coating (100,100') according to any one of claims 1 to 9, the method comprising the following steps: a. supplying a retaining film (4), b. bonding the lower face (5) of the support (1) to the retaining film (4), c. deposition of a precursor solution of the trapping layer (3) on the upper face (2) of the support (1), and d. photo-polymerization of the precursor solution so as to obtain the trapping layer (3).

Images