Manufacturing process for a decontamination wipe and corresponding wipe

Abstract

The invention relates to a method for manufacturing a surface, equipment, or skin decontamination wipe that may be contaminated by a toxic product in liquid form, comprising the steps of: - arranging fibers comprising more than 98% polypropylene in a continuous non-woven buffer layer, said fibers being continuous, - sandwiching the buffer layer between a first transfer veil and a second transfer veil, identical to the first transfer veil, each non-woven transfer veil comprising continuous fibers, said fibers comprising at least 60% polypropylene, and being configured to transfer the liquid toxic product from outside said transfer veil to the buffer by capillary action, - heat-sealing the first transfer veil, the buffer layer, and the second transfer veil, according to a predefined wipe shape, and - cutting said wipe. Abstract figure: Fig. 1

Description

Title of the invention: Method for manufacturing a decontamination wipe and corresponding wipe

[0001] The present invention relates to the field of dry decontamination, in particular the decontamination of surfaces contaminated by toxic liquids, in particular droplets of chemical weapons, known as "chemical warfare agents" or "agents" for short.

[0002] A solution known as a "powder glove" is known, based on smectite clay powder, or fuller's earth, which allows the powder to be spread on the contaminant to be absorbed with one side of the glove containing the powder, and the contaminated powder to be partially removed with the other side of the glove by wiping, the other side not containing powder.

[0003] However, such a solution has significant drawbacks: it does not neutralize the chemical agent and therefore produces toxic waste, which is itself contaminating. The contaminated powder is partially redeposited in the environment after wiping. The powder easily re-aerosolizes, causing secondary or cross-contamination, particularly via the airborne route; and finally, the powder must not come into contact with broken skin, the mouth, or the eyes, which is an operational constraint.

[0004] The present invention aims to remedy these drawbacks by proposing a different solution.

[0005] More specifically, according to a first of its objects, the invention relates to a method for manufacturing a surface, equipment or skin decontamination wipe, which may be contaminated by a toxic product in liquid form, comprising steps consisting of: - arranging fibers comprising more than 98% polypropylene in a non-woven buffer layer, randomly oriented, said fibers being continuous, - sandwiching the buffer layer between a first non-woven transfer veil and a second non-woven transfer veil, identical to the first transfer veil, each transfer veil comprising continuous fibers, said fibers comprising at least 60% polypropylene, and being configured to transfer the liquid toxic product from outside said transfer veil to the buffer by capillary action, - heat-seal the first transfer sheet, the buffer layer, and the second transfer sheet, according to a predefined wipe shape, and - cut up the said wipe.

[0006] It can be foreseen that the heat sealing step includes heat sealing and simultaneous cutting of the wipe; the cutting being carried out with a die heated to a temperature greater than or equal to the melting temperature of polypropylene.

[0007] A manufacturing step for a non-woven transfer veil can be envisaged, prior to the sandwich step, and comprising steps consisting of: - continuously extrude a polymer blend comprising at least 60% polypropylene using a die with a multilobed shape, to manufacture the continuous fibers of the transfer veil, - randomly arrange the said fibers of the transfer veil on a conveyor belt, and - to bind the said fibers of the transfer veil with water under pressure, so that they present in cross-section, a multilobed shape.

[0008] A step can be provided consisting of covering the cutter with a non-stick protective film prior to the cutting step.

[0009] A step can be provided consisting of tinting in the mass at least one of the first transfer veil and the second transfer veil to obtain a light color.

[0010] A step can be provided consisting of looping the non-stick protective film between two cylinders, in a closed circuit, the cutter being placed inside this loop.

[0011] According to another of its objects, the invention relates to a wipe manufactured by the process according to the invention, comprising: - a non-woven buffer layer comprising fibers containing more than 98% polypropylene, said fibers being continuous, randomly oriented, and exhibiting the capacity to absorb and store the liquid toxic product, - a first transfer veil and a second transfer veil, each non-woven transfer veil comprising continuous fibers, said fibers comprising at least 60% polypropylene, and being configured to transfer the liquid toxic product from outside said transfer veil to the pad by capillary action, - the buffer layer being sandwiched between the first transfer veil and the second transfer veil, - the first transfer layer, the buffer layer and the second transfer layer being heat-sealed.

[0012] It can be foreseen that the second transfer veil is identical to the first transfer veil, so that said wipe is reversible.

[0013] It can be anticipated that the buffer layer is configured to be able to absorb up to 600% of its mass in liquid toxic product.

[0014] It can be foreseen that the first transfer veil and the second transfer veil have a weight of between 50 and 70 g / m2, preferably 60 g / m2; and the buffer layer has a weight of between 200 and 300 g / m2.

[0015] Other features and advantages of the present invention will become more apparent from the following description given by way of illustrative and non-limiting example and made with reference to the accompanying figures.

[0016] [Fig-1] illustrates an embodiment of a device for manufacturing a wipe according to the invention,

[0017] [Fig.2] is an illustration of a cross-section of a fiber from a transfer web according to the invention, at the exit of the die,

[0018] [Fig.3] is an illustration of the fiber of [Fig.2], after a pressurized water treatment step,

[0019] [Fig.4] is a photograph of a wipe according to the invention. Detailed description

[0020] A wipe according to the invention is illustrated in [Fig.4].

[0021] It comprises a buffer layer sandwiched between two transfer veils.

[0022] A wipe according to the invention makes it possible to decontaminate a surface, for example a equipment or skin, which may have been contaminated by a toxic product in liquid form, which may have different viscosities, from fluid to oily.

[0023] The toxic product may be a warfare agent. In particular, the liquid warfare agent is mustard gas or an organophosphate nerve agent, notably VX.

[0024] The toxic product may also be a toxic industrial chemical product, including any of the products listed at the following address: https: / / www.osha.gov / emergency-preparedness / guides / toxic-industrial-chemicals.

[0025] For the purposes of the present invention, "agent" and "toxic product" are understood interchangeably.

[0026] In such a context, it is important, even essential, that a decontamination wipe has certain characteristics, including rapid absorption but also non-re-deposition.

[0027] As such, a wipe according to the invention is neither in the form of a sponge nor in the form of a product comprising discontinuous fibers, in particular cotton-based.

[0028] The advantage of continuous fibers is that they do not generate dust or particles, which could contaminate other surfaces later, for example such as cotton or a wipe made of discontinuous cellulosic or synthetic fibers.

[0029] - TRANSFER SAILS -

[0030] The transfer veil is a veil that resists the toxic product and allows for very rapid absorption of liquids or oils by capillary action. In this case, the thickness of the transfer veil is planned to be approximately 0.29 mm + / - 0.05 mm.

[0031] Preferably, the first and second transfer veil are melt-extruded nonwovens comprising a mixture of polypropylene (PP) and polyethylene terephthalate (PET).

[0032] At least 60% continuous PP fibers are expected; and in this case 70% continuous PP fibers and 30% continuous PET fibers, the values ​​of 70% and 30% being included with plus or minus 2% margin.

[0033] The advantage of continuous fibers is to prevent the resulting transfer veil from containing pieces of fibers.

[0034] The transfer veils are non-woven, the arrangement of the fibers is random and their properties are similar in all directions.

[0035] The transfer sail fibers pass through a die which has a multilobed shape, for example in the shape of a star, see [Fig.2], then they are burst by a jet of water under pressure, so that their cross-section has an even more marked multilobed shape, as illustrated in [Fig.3], which increases their specific surface area.

[0036] In [Fig.2] and [Fig.3], the light elements illustrate the PET part of the fiber, and the dark elements illustrate the PP part.

[0037] Bursting a fiber by pressurized water jet makes it possible to increase the distance between the PET part and the PP part of the fiber.

[0038] As illustrated in [Fig.2], D is the thickness of a PP portion of a fiber and El is the distance between the PP portion and the adjacent PET portion.

[0039] After bursting by pressurized water jet of the fiber illustrated in [Fig.2], the PP part and the adjacent PET part move apart from each other, and are finally at a distance E2 from each other, with E2 > EL. Figures 2 and 3 are not to scale.

[0040] Thanks to this characteristic, the fibers of the transfer veils have a specific surface area greater than that which they have before their treatment by pressurized water jet

[0041] In this case, the thickness of the transfer veil is less than 500 pm, and in this case equal to 300 pm, the equivalent diameter of the fibers of the veil being between 0.5 and 5 pm.

[0042] In addition, the star shape of the fibers allows the resulting transfer veil to exhibit capillary absorption characteristics, although polypropylene is naturally hydrophobic.

[0043] Preferably, the first transfer veil and the second transfer veil have a basis weight of between 50 and 70 g / m2, more preferably a basis weight of 60 g / m2

[0044] Preferably, the transfer veil is not calendered, as calendering reduces the capillary capacities of the transfer veil.

[0045] Thanks to the present invention, the transfer veils have, in addition to their transfer capacity, characteristics of non-spreading (less than 0.5%), non-redeposition, non-release and abrasion resistance.

[0046] Preferably, at least one of the first transfer veil and the second transfer veil has a light color.

[0047] Thanks to this feature, it is possible to visualize whether products have been absorbed by the wipe.

[0048] More particularly, it is planned to tint in the mass at least one of the first transfer veil and the second transfer veil to obtain a light color, in this case by colored pigments.

[0049] Since the wipe is reversible, it is possible to see which side of the wipe, and therefore which transfer veil, has been used.

[0050] - BUFFER DIAPER -

[0051] The buffer layer, of the non-woven type, also comprises absorbent fibers. These fibers, like the fibers of the transfer veils, are also continuous fibers. In this case, the buffer layer has an average thickness of 2 mm + / - 0.2 mm.

[0052]

[0053] They comprise more than 98% polypropylene, and are advantageously free of powders, free of glues, free of catalyst and free of solvent.

[0054] Indeed, the use of powder brings a risk of redeposition, the use of glue increases the weight and can bring a chemical risk, as can the use of catalyst or solvent.

[0055] Advantageously according to the invention, the melt spinning process for manufacturing the wipe avoids the use of chemical auxiliaries such as glue, solvent, etc., which can bring toxicological risks when used in contact with the skin.

[0056] In this case, more than 99.5% of continuous polypropylene fibers are planned, the remainder being pigments conforming to European regulatory requirements.

[0057] The fibers of the buffer layer have a substantially circular cross-section.

[0058] Due to the arrangement of its fibers and its non-woven nature, the buffer layer exhibits an absorption capacity. In this case, it can absorb up to 600% of the mass of the buffer layer in liquid toxic substances.

[0059] In this case, a wipe according to the invention has an absorption capacity of 40ml for a decontaminable surface of 3m2, i.e. the surface of an adult human body.

[0060] The buffer layer has a weight between 200 and 300 g / m2.

[0061] The fibrous structure does not act like a sponge; the toxic product remains stored. in the buffer layer, thanks to capillary forces.

[0062] - ASSEMBLY -

[0063] To manufacture a wipe according to the invention, a buffer layer is to be assembled in a sandwich between a first transfer veil and a second transfer veil, as illustrated in [Fig.1].

[0064] In this case, a first transfer veil is placed on a conveyor belt 100. A buffer layer 30 is deposited on the first transfer veil 10; and a second transfer veil 20, identical to the first transfer veil, is deposited on the buffer layer 30.

[0065] Each transfer web and buffer layer originates from a respective roller. The rollers cut their web / layer at the speed of movement of the conveyor belt, the direction of which is illustrated by the double arrow, which drives the rollers in rotation.

[0066] Once the first transfer veil, the buffer layer and the second transfer veil are superimposed on the conveyor belt and advancing synchronously, an assembly step and a cutting step are planned, which in this case are advantageously simultaneous.

[0067] In this case, a cutter 300 is provided, positioned above the conveyor belt, the shape and dimensions of which are those of a wipe.

[0068] The die is heated to a temperature greater than or equal to the melting temperature of polypropylene, so that the application of the die to the sandwich heat-welds the first transfer veil, the buffer layer and the second transfer veil together.

[0069] The punch comprises heatable blades, parallel to each other and to the plane of the wipe, each blade coming into compression in contact with a respective transfer veil.

[0070] The temperature of the die is greater than or equal to the melting temperature of the polypropylene, so that the polypropylene of each layer melts when it is applied. The polypropylene of the first transfer layer bonds with that of the buffer layer and with that of the second transfer layer, thus creating a weld upon cooling, advantageously without glue.

[0071] Preferably, the upper transfer sheet, i.e. the transfer sheet located on the side of the cutter, is covered with a 200 non-stick protective film whose melting point is higher than that of polypropylene, so that heating the cutter melts the polypropylene of the different layers of the wipe but not that of the non-stick protective film.

[0072] For example, the non-stick protective film comprises a polyimide material in particular Kapton (registered trademark).

[0073] The non-stick protective film prevents the molten polypropylene from sticking to the cutter when it is removed.

[0074] In this case, the non-stick protective film is looped between two cylinders 210, 220, in a closed circuit, and the cutter is placed inside this loop. Each time the cutter is cut, the cylinders rotate by a predetermined angle, so that the non-stick protective film that has just been used for one cut is not used for the next.

[0075] Preferably, the non-stick protective film is replaced after a predetermined number of cycles.

[0076] Preferably, the cutter has a beveled shape, which is heated to a temperature between the melting temperature of polypropylene and the melting temperature of the non-stick protective film.

[0077] A first die can be provided for heat-sealing the first transfer veil and the buffer layer; and a second die, to the right of the first, for heat-sealing the second transfer veil and the buffer layer.

[0078] - USAGE -

[0079] Preferably, a wipe according to the invention is to be used by applying it to the surface to be decontaminated.

[0080] Thanks to the present invention, since it is essentially based on polypropylene, a chemically inert polymer, the decontamination wipe does not present a risk of exothermic or explosive reaction in contact with the agent.

[0081] Polypropylene, which is advantageously chemically inert and stable, does not degrade in contact with toxic products.

[0082] In addition, polypropylene welds well with itself, which is why the transfer veils and the buffer layer comprise a proportion of more than 50% of it.

[0083] Thanks to the present invention, it is possible to obtain a decontamination rate of more than 99% on skin and surfaces, a minimum value guaranteeing acceptable residual toxicity, whereas a powder glove, for example, has a decontamination rate of about 85% on skin, the contamination being confined in the wipe, while the powder glove causes a dispersion of the contamination on the site of use.

[0084] The surface area that can be decontaminated with a wipe is preferably at least 3m2. A larger surface area can be provided, for example so that the same wipe can be used to decontaminate an individual and their equipment.

[0085] Advantageously, a wipe according to the invention does not require rinsing after use.

[0086] Tests have been carried out and a wipe according to the invention decontaminates more than 99% of the chemical agents tested on any type of surface and skin, regardless of the protocol or decontamination technique used, and regardless of the equivalent diameter of the drops.

[0087] Thanks to the buffer layer, the toxic product remains in the wipe, which reduces the risks of cross-contamination by internal storage of the toxic product.

[0088] Similarly, the wipe according to the invention avoids over-contamination by spreading, and the redeposition of the absorbed agent on surfaces that were initially not contaminated.

[0089] It does not exhibit an exothermic or explosive reaction.

[0090] Preferably, a wipe according to the invention is marketed in airtight packaging which not only allows easy storage for a period of more than 10 years, but the packaging also allows it to be transformed into a waste bag after use of the wipe.

Claims

Demands

1. A method for manufacturing a surface, equipment or skin decontamination wipe, which may be contaminated by a toxic product in liquid form, comprising the steps of: - arranging fibers comprising more than 98% polypropylene in a non-woven type buffer layer, randomly oriented, said fibers being continuous, - sandwiching the buffer layer between a first non-woven type transfer veil and a second non-woven type transfer veil, identical to the first transfer veil, each transfer veil comprising continuous fibers, said fibers comprising at least 60% polypropylene, and being configured to transfer the liquid toxic product from outside said transfer veil to the buffer by capillary action, - heat-sealing the first transfer veil, the buffer layer and the second transfer veil, according to a predefined wipe shape, and - cutting said wipe;characterized in that it comprises a manufacturing step of a non-woven type transfer veil, prior to the sandwich step, and comprising steps consisting of: - continuously extruding a polymer mixture comprising at least 60% polypropylene with a die which has a multilobed shape, to manufacture the continuous fibers of the transfer veil, - randomly arranging said fibers of the transfer veil on a conveyor belt, and - bonding said fibers of the transfer veil with pressurized water, so that they have, in cross-section, a multilobed shape.;

2. A method according to claim 1, wherein the heat-sealing step comprises heat sealing and simultaneous cutting of the wipe; the cutting being carried out with a die heated to a temperature greater than or equal to the melting temperature of polypropylene.

3. A method according to any one of the preceding claims, comprising a step of covering the cutter with a non-stick protective film prior to the cutting step.

4. A method according to any one of the preceding claims, comprising a step of mass-dyeing at least one of the first transfer veil and the second transfer veil to obtain a light color.

5. A method according to any one of claims 3 or 4, comprising a step of looping the non-stick protective film between two cylinders, in a closed circuit, the cutter being disposed inside this loop.

6. Wipe manufactured by the process according to any one of the preceding claims, comprising: - a non-woven type buffer layer comprising fibers comprising more than 98% polypropylene, said fibers being continuous, randomly oriented, and having a capacity for absorbing and storing the liquid toxic product, - a first transfer sheet and a second transfer sheet, each non-woven type transfer sheet comprising continuous fibers, said fibers comprising at least 60% polypropylene, and being configured to transfer the liquid toxic product from outside said transfer sheet to the buffer by capillary action, - the buffer layer being sandwiched between the first transfer sheet and the second transfer sheet, - the first transfer sheet, the buffer layer and the second transfer sheet being heat-sealed.

7. Wipe according to claim 6, wherein the second transfer layer is identical to the first transfer layer, so that said wipe is reversible.

8. Wipe according to any one of claims 6 or 7, wherein the buffer layer is configured to be able to absorb up to 600% of its mass in liquid toxic product.

9. Wipe according to any one of claims 6 to 8, wherein the first transfer layer and the second transfer layer have a basis weight of between 50 and 70 g / m2, preferably 60 g / m2; and the buffer layer has a basis weight of between 200 and 300 g / m2.

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