COATING FOR DECONTAMINATION OF TOXIC CHEMICAL COMPOUNDS

Abstract

A decontamination coating and method for manufacturing the decontamination coating, wherein the decontamination coating includes a multilayer structure including a support, a trapping layer intended to be brought into contact with the toxic chemical compounds so as to trap them, and a holding film 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.

Claims

1. A decontamination coating 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, a trapping layer formed on an upper face of the support, the trapping layer being intended to be brought into contact with the toxic chemical compounds so as to trap them, and a holding film secured to a lower face of the support opposite the upper face the holding 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.

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

3. The decontamination coating according to claim 1, wherein the support is formed from at least one foamed polymer layer.

4. The decontamination coating according to claim 1, wherein, the support comprises an upper subsurface including a trapping layer portion impregnated into the support.

5. The decontamination coating according to claim 1, wherein the support is formed from at least one polyurethane foam layer.

6. The decontamination coating according to claim 1, wherein 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.

7. The decontamination coating according to claim 6, wherein the lower adsorbent layer comprises at least one polyurethane foam impregnated with an adsorbent porous material.

8. The decontamination coating according to claim 7, wherein the adsorbent porous material comprises activated carbon.

9. The decontamination coating according to claim 6, which comprises a bonding film between the lower adsorbent layer and the upper layer.

10. A decontamination assembly comprising the decontamination coating according to claim 1 and a packaging device for preserving the decontamination coating, the packaging device being formed by a multilayer assembly comprising at least one aluminum layer and one PET (PolyEthylene Terephthalate) layer.

11. A method for manufacturing the decontamination coating according to claim 1, the method comprising the following steps: a) providing a holding film, b) securing the lower face of the support to the holding film, c) depositing a precursor solution of the trapping layer on the upper face of the support, and photopolymerization of the precursor solution so as to obtain the trapping layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0122] Other aspects, purposes and advantages of the present invention will better appear on reading the following description of two embodiments thereof, given as a non-limiting example and made with reference to the appended drawings. The figures do not necessarily respect the scale of all the elements represented so as to improve their readability. In the following description, for simplicity, identical, similar or equivalent elements of the different embodiments bear the same numerical references.

[0123] FIG. 1 illustrates a schematic view of a cross-section of a decontamination coating according to a first embodiment of the invention.

[0124] FIG. 2 illustrates a schematic view of the decontamination coating in a position rolled up on itself in preparation for packaging.

[0125] FIG. 3 illustrates a schematic view of a cross-section of a decontamination coating according to a second embodiment of the invention.

DETAILED DESCRIPTION

[0126] In the figures and in the following description, the same references represent identical or similar elements. Moreover, the different elements are not shown to scale so as to enhance the clarity of the figures. In addition, the different embodiments and variants are not mutually exclusive and may be combined with each other.

[0127] Unless otherwise stipulated, the term substantially means, in the present document, exactly or to within 10% or 10.

[0128] As illustrated in FIG. 1, the decontamination coating 100 comprises a support 1 on the upper face 2 of which is formed a trapping layer 3 and a holding film 4 secured to the lower face 5 of the support 1 through an adhesive film 6. The support 1 comprises a porous material layer obtained by a foamed polymer such as a polyurethane foam. The support 1 may also be a polyester-based non-woven material capable of fulfilling the same role in the decontamination coating 100 as a polyurethane foam. The support 1 is sufficiently flexible to be able to roll up on itself (refer to FIG. 2), even once secured to the trapping layer 3 and to the holding film 4, which facilitates its packaging, in particular when it is manufactured in the form of a continuous strip.

[0129] The trapping layer 3, intended to be brought into contact with the toxic contaminants, is formed by coating on 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: [0130] at least one monomer comprising an (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide group, [0131] at least one crosslinking agent comprising at least two groups selected from (alkyl)acrylic, (alkyl)acrylate or (alkyl)acrylamide groups, [0132] at least one photopolymerization initiator [0133] and at least one agent selected from alkali halides, alkali phosphates, alkali sulfates and mixtures thereof, all of which being diluted in a protic solvent, such as water.

[0134] The precursor solution is deposited by coating and penetrates into the upper subsurface of the porous support 1 over a few tenths of a mm, by simple gravity, the time required to carry out the photopolymerization. This generates the formation of a trapping layer 3 portion 7 impregnated into the support 1, which allows good adhesion between the latter and the trapping layer 3.

[0135] The holding film 4 is adhered to the lower face 5 of the support 1 prior to coating with the precursor solution so as to complete and achieve the rigidity required for the support 1 so that it retains its shape (layer extending in a plane and including at least two parallel sides) and its flatness during the steps of forming the trapping layer 3.

[0136] FIG. 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 polyurethane foam-based two-layer assembly 8, 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 through a hot-melt bonding film 12. The lower adsorbent layer 11 is a polyurethane foam-based layer impregnated with activated carbon. This configuration is in particular configured to improve decontamination in the presence of contaminating compounds that are more volatile or at least capable of migrating through the thickness of the decontamination coating 100, 100.

[0137] 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.

[0138] Decontamination tests are thus carried out by the French Directorate General for Armaments (DGA) using samples 200, 200 of both types of decontamination coating 100, 100 (without and with activated carbon) against organophosphorus combat gases, according to the recommendations of the standard AEP-65 (NATO standard), adapted in particular to the specificities of the samples 200, 200.

[0139] Samples 200, 200 with a surface area of 55 cm.sup.2 and comprising a thickness between 3 and 4 mm are removed from their packaging just before carrying out the decontamination tests.

[0140] An example of preparing a precursor solution of a trapping layer 3 in accordance with one embodiment of the invention is described below.

[0141] In a 30 ml pill organizer, previously dried in an oven overnight at 90 C. under dynamic vacuum and packaged 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.

[0142] A magnetic stir bar is introduced into the resulting medium. The medium is then purged with argon and magnetically stirred until the solid compounds, such as IRGACURE 184 and potassium fluoride, are completely dissolved.

[0143] The precursor solution is deposited by coating on the upper surface 2 of the support 1,8. Complete gelation of the precursor solution is achieved after 9 minutes of exposure with a UV lamp emitting a wavelength of 405 nm with a power of 9000 W/m.sup.2. The hydrogel thus formed makes it possible to obtain the decontamination coatings 100, 100.

[0144] At the same time, the contaminating compounds are arranged on a HDPE (High Density Polyethylene) support, having a flat surface. Once the supports are contaminated, they are arranged in a hermetic enclosure that is temperature-controlled at approximately 30 C. for 90 minutes.

[0145] Then, the decontamination coating 100, 100 is placed on the surface of the contaminated support while exerting pressure (20 g/cm2) and the assembly maintained under pressure is placed for 1 hour in a temperature-controlled enclosure at approximately 30 C.

[0146] 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/liquid chromatography depending on the contaminant in order to perform the calculations of the amount of contaminant trapped in the decontamination coating 100,100.

[0147] These tests are repeated five times for each of three toxic organophosphorus chemical compounds (compounds A, B and C) and this 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 called the hydrogel coating hereinafter).

[0148] The results of these tests illustrated in table 1 below report the decontamination efficiency of sample 200 with respect to the hydrogel coating alone (for the same natures of material of the trapping layer) and the decontamination efficiency of sample 200 with respect to the hydrogel coating alone (refer in particular to document EP3740514 for the application of the hydrogel alone).

TABLE-US-00001 TABLE 1 Rate of Rate of Rate of improvement of improvement of improvement of decontamination decontamination decontamination Considered with respect to with respect to with respect to coatings Compound A Compound B Compound C Sample 200/ 97.00% 65.00% 63.00% hydrogel coating only Sample 200/ 100.00% 88.00% 94.00% hydrogel coating only

[0149] The decontamination tests carried out show that the decontamination coatings 100 (sample 200), 100 (sample 200) are more effective than the use of a hydrogel coating alone (for example, 97% improvement of decontamination is observed between sample 200 and the hydrogel coating alone with respect to compound A). The decontamination coating 100 comprising activated carbon is particularly effective for decontaminating organophosphorus contaminants present on a smooth support.

[0150] In addition, after one year's packaging of samples 200, 200 of decontamination coatings 100, 100 in the previously described packaging devices, the test results show the same level of decontamination. It is thus possible to conclude that the trapping layer 3 does not undergo aging over this period under these packaging conditions.

[0151] Thus, the present invention provides highly effective decontamination coatings against toxic chemical compounds, in particular organosphorus compounds, 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.