Protective material with no added pfas

Abstract

A protective material is disclosed which includes a barrier layer, and an outer layer, wherein the barrier layer comprises a flexible material substrate, at least one reactive sorbent and optionally a binder, and the reactive sorbent is loaded on the flexible material at 5 to 600 g / m2 dry weight, and wherein the outer layer comprises a fabric.

Description

[0001] PROTECTIVE MATERIAL WITH NO ADDED PFAS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to protective materials, in particular protective garments, tents, gurneys, and to processes for production of such protective materials. In particular, the present invention relates to effective protective materials that may have no intentionally added PFAS (polyfluoroalkyl substances) and hence may be free from PFAS or low in PFAS or fluorocarbons (FC).

[0004] BACKGROUND TO THE INVENTION

[0005] Exposure to toxic agents, such as chemical warfare agents (CWA) and related toxins, is a potential hazard to the armed forces and to civilian populations. Examples of commonly known CWA are bis-(2-chloroethyl) sulfide (HD or mustard gas), pinacolyl methylphosphonothiolate (soman or GD), sarin (GB), cyclosarin (GF), and O-ethyl S-(2- diisopropylamino)ethyl methylphosphonothiolate (VX), as well as analogues and derivatives of these agents. CW agents may be delivered as fine aerosol mists which may be inhaled by personnel and may deposit on surfaces of equipment, structures and hardware. If such surfaces have been contaminated, the CWA must be removed in order to reduce contact hazards and to return the item to service.

[0006] Contamination with toxic industrial chemicals (TIC) including pesticides (for example AChE-inhibiting pesticides such as parathion, paraoxon, diazinon and malathion) as well as toxic industrial materials (TIM) can also be problematic and can result in contamination of surfaces.

[0007] There have been attempts to provide adsorption and absorption materials for use in protective equipment such as clothing, gloves and masks and for use in decontamination wipes, mitts, and other items.

[0008] A common adsorbent is activated carbon which may have a high surface area (e.g. 1000 m2 / g or higher) and works mainly by adsorbing toxic compounds. Activated carbon may be in the form of activated carbon powder, activated carbon cloth and activated carbon beads. Activated carbon may have mesoporosity (pores of around 5 nm to 50 nm in size) and micro porosity (pores less than 2 nm in size) but there is a limit to how much control is available to produce specific pore sizes. Activated carbons can be used for decolorizing, deodorizing and adsorbing CWA and retain such agents in the pore structure.

[0009] There have been attempts to use other adsorbents such as metal oxides, metal hydroxides and metal oxyhydroxides which may adsorb and decompose chemical warfare agents. Examples of such metal oxides, metal hydroxides and metal oxyhydroxides include zinc oxide, aluminium oxide, zinc hydroxide, copper oxide supported on activated carbon, and on composites of graphite oxide and hydrous ferric oxide or zirconium hydroxide, tungsten oxide, and copper hydroxyl nitrate. Other materials that also show promise include zinc titanate, metal-organic framework (MOFs, for example zirconium metal organic framework materials) and the complex polyniobate Ki2[Ti202][GeNbi204o]-19 H2O, and Ti / Fe, Al / Fe, Ti / Al, Cu / Fe, Zn / Fe and Ti / Zn mixed oxides (see for example Florent et al., “Mixed CuFe and ZnFe (hydr)oxides as reactive adsorbents of chemical warfare agent surrogates”, Journal of Hazardous Materials, 329 (2017), pp. 141-149). Other materials include metal oxides and hydroxides that may be produced with controlled pore size and surfaces areas.

[0010] US-B-8,530,719 and US-B-10,245,456 disclose the use of zirconium hydroxide and zirconium hydroxide loaded with zinc, triethylenediamine, or zinc plus triethylenediamine to detoxify chemical agents VX and GD. US-B-10,828,873 discloses a textile composite including a layer with the ability to protect against highly toxic agents and chemicals including chemical warfare agents, industrial chemicals and insecticides using a material of aluminium oxide, silicon-aluminium oxide, zirconium hydroxide, magnesium oxide or titanium dioxide to absorb or adsorb toxic chemicals and subsequently detoxify the adsorbed or absorbed toxic chemical. US-B-9,907,988 discloses processes for decontaminating surfaces using porous metal hydroxides. US-B-9,623,404 and US-A-2010 / 0081186 disclose metal organic framework materials and methods to catalytically detoxify CWA. WO / 2022 / 243658 discloses flexible substrates, a sorbent comprising zirconium hydroxide and a binder.

[0011] The use of adsorbents (which often adsorb solely by physisorption processes) does not generally remove the activity of a CWA so subsequent processes are also required to ensure safety. Furthermore, adsorbed agents can be desorbed by other compounds (e.g. fuels) which may mean that personnel may be at risk of exposure even after the initial adsorption / capture of the CWA.

[0012] Chemical, biological, radiological and nuclear defence (CBRN) clothing used by military forces may have adsorbent material sandwiched between layers of textiles. The adsorbent may be in the form of activated carbon beads made by the carbonization of resinous thermoset beads, typically 300 pm in diameter. Such a system is effective in adsorbing CWA but does not neutralize the CWA.

[0013] Protective material and garments to handle toxic chemicals (including CWA) have previously used extensive amounts of PF AS (polyfluoroalkyl substances). PF AS have previously served two main functions: water repellency to prevent the user getting wet and to prevent the water from saturating the barrier material, and to provide chemical repellency, especially chemical repellency to oils; since the application of the fluorocarbon (FC) on a fabric gives low surface energy so that liquids which have higher surface tension remain as beads on the surface (where the surface energy is higher, the liquid may spread). Thus, PF AS repellency to oil provides a level of protection to the wearer of protective garments owing to the oleophobic properties of PF AS, so that CWA and other toxic chemicals may be repelled off the surfaces of the textile, but the garment remains breathable allowing vapour (moisture) to be transported through the fabric.

[0014] In the case of CBRN protection, it has been believed that PFAS treatment has been important since the function of a CBRN garment is to prevent the ingress of the agent to the wearer and a PFAS treatment has been considered important to hold back the agent or control the movement of agent through the garment.

[0015] The belief has been that droplets of CWA (or other toxic chemicals) landing on the garment would be repelled and prevented from soaking through. This has been considered to be advantageous because if there is no PFAS finish then the CWA may soak through the garments and wet out (or the evaporated vapour may overwhelm) the adsorbent system, thereby exceeding the adsorption capacity of the sorbent. Thus, the CWA would pass through the barrier material and be able to make contact with the skin of the wearer.

[0016] It has been considered that PFAS treatment delays the rate of penetration of the CWA through the garment, volatile CWAs may bead on the garment and evaporate slowly thus reducing overall challenge by the CWA. Although vapour may enter the garment, the concentration of the vapour is more controlled and so it has been considered that a barrier adsorbent system in the garment is better able to sorb the agent and thereby avoid problems of point overwhelming where local concentration of the toxic chemical in the form of the bead or liquid can overwhelm the sorbent system.

[0017] Recently, there have been concerns that PF AS are environmentally damaging since they are known to build up in the environment and are persistent. Some regulatory authorities have banned PFOA (perfluoro octanoic acid; a precursor for manufacturing C8 fluorocarbons, FC) and other PFAS / FC are likely to be restricted in the future.

[0018] There is, therefore, a need to provide improved materials that do not require the use of FC / PFAS materials or treatments and are effective without such materials / treatments.

[0019] It is an aim of the present invention to address this need.

[0020] SUMMARY OF THE INVENTION

[0021] In one aspect, the present invention accordingly provides a protective material comprising a material, the material comprising: a barrier layer, and an outer layer, wherein the barrier layer comprises a flexible material substrate, at least one reactive sorbent and optionally a binder, and the reactive sorbent is loaded on the flexible material at 5 to 600 g / m2dry weight, and wherein the outer layer comprises a fabric.

[0022] Preferably, the reactive sorbent is loaded on the flexible material at 30 to 600 g / m2dry weight.

[0023] Preferably, no PF AS is intentionally added to the protective material, i.e. the protective material has no intentionally added PF AS and is preferably substantially PFAS- free.

[0024] This is greatly advantageous because it provides material that surprisingly is still effective against CWA even when not treated with a PF AS system. Without wishing to be bound, it appears that the mechanism for protection may be as follows. In the absence of a PF AS system the outer layer and barrier layer / material will absorb the CWA readily, and so the outer fabric without a PF AS treatment will now be prone to wetting out by the CWA and also the barrier material. Thus, a greater quantity of the CWA / toxic chemical may be held in the structure of the textile. In contrast, if the CWA / toxic chemical was in the surface of the material in bead form i.e. liquid drop then this becomes a contact hazard as a greater proportion is available to be transferred during contact with another individual or surface, causing transfer of the CWA to the new surface. However, if the CWA is sorbed by the outer layer it is now not readily available for transfer and would have to be squeezed out of the outer layer to make liquid CWA transfer. Spreading of the toxic chemical in the outer layer may also mitigate risks of point overwhelming and provide more surface area of the barrier layer for the toxic chemical / CWA to be sorbed.

[0025] The reactive sorbent may be held in the flexible material substrate by mechanical means (e.g. trapped in the structure of the substrate or trapped between substrates) or may be held by an optional binder. Optionally, the sorbent may be present on the fibre or in the fibre depending on fibre type used. In some embodiments, the reactive sorbent may be present in and / or on a film.

[0026] Preferably, the barrier layer further comprises at least one further sorbent.

[0027] Alternatively, there may be at least one further layer comprising a further sorbent.

[0028] The further sorbent may comprise activated carbon, impregnated carbon, a resin, a zeolite and / or an additional reactive sorbent.

[0029] The reactive sorbent and / or additional reactive sorbent may comprise an oxide, hydroxide or oxy-hydroxide of aluminium, silicon, magnesium, calcium, titanium, manganese, iron, cobalt, copper, zinc, hafnium and zirconium, a metal-organic framework material (MOF) or mixtures thereof.

[0030] Mixed metal oxides, hydroxides and oxy-hydroxides may be examples of reactive sorbents. A metal oxide is comprised of metal and oxygen, a metal hydroxide is comprised of metal and hydroxyl groups while a metal oxy-hydroxide is comprised of a metal and usually bridging oxygen plus hydroxyl groups. Examples are metal oxy-hydroxides and mixed-metal oxy-hydroxides. Examples of metal oxy-hydroxides include zirconium oxy-hydroxide (often referred to as zirconium hydroxide), and aluminium oxy-hydroxide (often referred to as aluminium hydroxide, boehmite or pseudo-boehmite). Examples of mixed metal oxyhydroxides include silicon-zirconium oxy-hydroxide and titanium-zirconium oxy-hydroxide, aluminium oxide, silicon-aluminium oxide, magnesium oxide and / or titanium dioxide.

[0031] Examples of metal oxides, metal hydroxides and metal oxyhydroxides include zinc oxide, aluminium oxide, aluminium oxyhydroxide, aluminium hydroxide, zinc hydroxide, copper oxide, ferric or ferrous oxide, ferric or ferrous hydroxide, or zirconium hydroxide, tungsten oxide, and copper hydroxyl nitrate. Other materials may include zinc titanate, metal- organic framework (MOFs, for example zirconium metal organic framework materials), the complex polyniobate Ki2[Ti202][GeNbi204o]-19 H2O, and Ti / Fe, Al / Fe, Ti / Al, Cu / Fe, Zn / Fe and Ti / Zn mixed oxides, hydroxides or oxyhydroxides.

[0032] MOF refers to Metal-Organic Frameworks which comprise metal ions or clusters coordinated to organic ligands to form one-, two-, or three-dimensional structures. Preferably the MOF is porous. The organic ligands included may be referred to as "struts" or "linkers", one example of a strut is 1,4-benzenedicarboxylic acid (BDC).

[0033] More formally, a metal-organic framework refers to a coordination network with organic ligands containing potential voids. A coordination network is a coordination compound extending, through repeating coordination entities, in one dimension, but with cross-links between two or more individual chains, loops, or spiro-links, or a coordination compound extending through repeating coordination entities in two or three dimensions. A coordination polymer is a coordination compound with repeating coordination entities extending in one, two, or three dimensions. The preferred metal in a MOF for use in the invention is Zr. Examples of MOF materials include the zirconium metal-organic framework materials UiO-66 and U1O-66-NH2.

[0034] Preferably, the reactive sorbent and / or additional reactive sorbent comprises an oxide, hydroxide or oxy-hydroxide of zirconium.

[0035] The protective material may have one or more further barrier layers. Other layers of the material may have a reactive sorbent system and / or a sorbent system on a surface or impregnated within them. The position of the reactive sorbent layer(s) and other layer(s) may be varied in the protective material.

[0036] In some embodiments, the protective material may comprise the barrier layer comprising the flexible material substrate, at least one reactive sorbent and optionally a binder, and a second barrier layer comprising one or more sorbents, for example a non- reactive (e.g. activated carbon, and / or carbon bead) sorbent. The barrier layer and second barrier layer may be arranged in different arrangements in the protective material. For example, the second barrier layer (nonreactive sorbent e.g carbon bead or activated carbon cloth) may be adjacent to and / or bonded directly to the reactive sorbent barrier layer, or another layer may be situated between the reactive sorbent layer and the second barrier layer. Thus, in an aspect, there is provided a protective material comprising a material, the material comprising: a first barrier layer, at least a second barrier layer, and an outer layer, wherein the first barrier layer comprises a flexible material substrate, at least one reactive sorbent and optionally a binder, and the reactive sorbent is loaded on the flexible material at 5 to 600 g / m2dry weight, the second barrier layer comprises a flexible material substrate, at least one (optionally different) sorbent and optionally a binder, and wherein the outer layer comprises a fabric.

[0037] It is envisaged that the final composite will be dictated by the end user requirements in terms of CWA performance, weight, thermal burden, comfort, durability and cost. Indeed, the present disclosure provides great advantages in allowing extended mission times because of improved thermal and CWA protective properties of the protective material.

[0038] Thus, in an additional aspect there is provided a protective garment comprising a protective material according to the first aspect, the protective garment providing CWA protective properties, and, when in use (i.e. when worn), reduced thermal load.

[0039] In another aspect, there is provides a process for production of a protective material, the process comprising: a) providing a flexible material, b) providing at least one PFAS-free sorbent dispersion comprising a binder and an amount of reactive sorbent, so that the reactive sorbent is to be loaded on the flexible material at 5 to 600 g / m2dry weight, c) applying the sorbent dispersion to the flexible material to produce a treated flexible material, d) squeezing the treated flexible material under pressure, e) passing the pressed treated flexible material through a stenter, and f) optionally repeating any one of steps b), c), d) and / or e) to produce a barrier material, and g) disposing an outer layer on the barrier material.

[0040] Preferably, the reactive sorbent is loaded on the flexible material at 30 to 600 g / m2dry weight. Preferably, the reactive sorbent may have a particle size in the range 0.05pm to 300 pm, or 0.1 to 100 pm, preferably 1 pm to 55 pm or 2 pm to 55 pm, more preferably 2 pm to 45 pm or 3 pm to 45 pm.

[0041] It is preferred that the flexible material substrate comprises a foam (e.g. an open cell or closed cell foam) or a textile. The textile may be selected from a knitted textile, a woven textile and a non-woven textile. Preferably, the textile is a knitted textile (e.g. weft or warp knitted), optionally a pile knitted textile. To further improve the amount of sorbent impregnated, the textile may be bulked, for example by being texturised through the use of texturized yarns or mechanically manipulated to create bulk.

[0042] The textile may comprise natural fibres, synthetic fibres or a combination of natural and synthetic fibres. It is advantageous if the textile comprises elastane. This is advantageous because the use of elastane may improve stretch, conformability and recovery. Alternatively, or additionally, the structure of a fabric and / or texturization of the yarns may be adapted to provide a conformable material with suitable stretch characteristics.

[0043] Preferably, the flexible material substrate is at least partially porous.

[0044] The sorbent dispersion will usually further comprise a solvent, for example ethanol, propanol, and / or water, preferably water to provide a sorbent aqueous dispersion. Other solvents, for example aliphatic or aromatic lower hydrocarbons, could potentially be used; examples include hexane, benzene, or toluene. Acetone or diethyl ether may alternatively be used.

[0045] To improve impregnation, it is beneficial that the impregnated flexible material is pressed at a predetermined pressure. Generally, the impregnated flexible material may be pressed at a predetermined pressure in the range 1 psi (6.9 kPa) to 150 psi (1 MPa), optionally 20 psi (138 kPa) to 100 psi (0.69 MPa), optionally 70 psi (0.48 MPa) to 100 psi (0.69 MPa). The pressure may depend on the device used to press the flexible material. For example, a mangle may use a pressure in the range 10 psi (69 kPa) to 100 psi (690 kPa)

[0046] The sorbent dispersion may have a viscosity in the range 40 cps to 4000 cps, optionally 50 cps to 2000 cps, optionally 100 cps to 1000 cps, optionally 200 cps to 600 cps. The pressure may be adjusted in order to increase or decrease the loading of each pass. The viscosity of the sorbent solution may be adjusted for different applications. The viscosity is a useful feature to aid keeping the sorbent suspended in solution. The solids weight ratio of the binder to the reactive sorbent in the product aspect or the process aspect may be in various ranges. Usually, when the fabric is intended for garment materials the binder ratio may be such that there is a higher proportion of binder to improve durability e.g. a solids weight ratio in the range binder: reactive sorbent of 1 : 1 to 1 :24, preferably 1 : 1 to 1 : 12, preferably 1 : 1 to 1 : 10, more preferably 1 : 1 to 1 :4. When the fabric is intended for other uses the lower amount of binder may be useful (since the sorbent may not need to be as durable but will also provide an increase in sorbancy) of e.g. solid weight ratio of binder: reactive sorbent of 1 : 12 to 1 : 120, preferably 1 : 12 to 1 :40.

[0047] The dispersion may further comprise a polymeric thickener, a protective colloid, and / or a wetting agent. The protective colloid may be selected from carboxy methyl cellulose, methyl cellulose, hydroxy propyl methyl cellulose, Xanthan gum and / or polyvinyl alcohol but others are available.

[0048] The barrier layer and outer layer may be abutted or joined, for example the barrier layer and outer layer may joined on at least a portion thereof by stitching, adhesive, and / or lamination.

[0049] The outer layer may comprise a fire-resistant material, optionally fire retardant nylon- cotton, or an aramid, optionally a meta-aramid or a para-aramid.

[0050] The outer layer may comprise a PFAS-free water repellent treatment.

[0051] The outer layer may have a reactive sorbent and / or sorbent layer / system on a surface (e.g. an inner surface) thereof.

[0052] The protective material may further comprise a filtration layer (also known as an aerosol layer). The filtration layer may be disposed between the barrier layer and the outer layer, or at another location. The filtration layer may exclude particles of size 0.1 pm to 7 pm, optionally 0.3 pm to 3 pm.

[0053] The protective material may further comprise a comfort liner. The comfort liner may be disposed, optionally on the surface of the barrier layer, away from the outer layer.

[0054] The barrier layer and a filtration layer, and optionally the comfort liner, may be laminated together. The barrier layer and a filtration layer, and optionally the comfort liner, may be laminated together with an adhesive disposed, at least partially, optionally between the barrier layer and the filtration layer, and optionally between the barrier layer and the comfort liner.

[0055] The adhesive may comprise an adhesive web, adhesive powder and / or a plurality of adhesive dots. A perforated or slit adhesive film may be used. A solid adhesive film may be used. Air permeability, moisture transportation, handle and adhesion properties may be modified using such adhesive films.

[0056] The adhesive may comprise a cross-linkable adhesive.

[0057] The binder may comprise a polymeric emulsion, optionally selected from an acrylic, a polyurethane, a natural rubber latex, chloroprene, styrene-butadiene rubber (SBR) and / or nitrile rubber. The binder can also be a dispersion of a polymer and may or may not be an emulsion.

[0058] The dispersion may have a pH in the range 3 to 14, optionally 6 to 12. This is advantageous because this pH range may improve thickening for e.g. an alkali swellable thickening agents. Alternatively, the pH can be 3 to 7 for e.g. a higher solids and / or using a thickener working on a different thickening mechanism.

[0059] The process and product may usually be adapted e.g. by varying the number of passes (i.e. repeats in the process) viscosity of the dispersion, loading of sorbent in the dispersion and hence on product and / or pressure of the roller). For example, the sorbent may be loaded on the flexible material at 10 to 600 g / m2dry weight, optionally at 15 to 600 g / m2dry weight, optionally at 20 to 600 g / m2dry weight, optionally at 25 to 600 g / m2dry weight, optionally at 30 to 600 g / m2dry weight, optionally at 45 to 600 g / m2dry weight, optionally at 50 to 600 g / m2dry weight, optionally at 55 to 600 g / m2dry weight, optionally at 65 to 600 g / m2dry weight, optionally at 75 to 600 g / m2dry weight, optionally at 85 to 600 g / m2dry weight, optionally at 95 to 600 g / m2dry weight, optionally at 105 to 600 g / m2dry weight, optionally at 150 to 550 g / m2dry weight, optionally at 175 to 525 g / m2dry weight, optionally at 200 to 500 g / m2dry weight; suitably at 250 to 500 g / m2dry weight or 100 to 500 g / m2dry weight.

[0060] The sorbent dispersion may be applied to the flexible material by any suitable method. The method may be selected from dipping (impregnation), knife over air coating, knife over roller coating and transfer coating, gravure coating, dot coating, and / or spray coating. In order to modify the loading or to produce more than one sorbent or sorbent-loading in the fabric, the steps b) to e) of the process may be repeated at least once to increase the sorbent loading on the flexible material. Thus, applying the sorbent dispersion to the flexible material may use a first sorbent dispersion and a second sorbent dispersion (that may be different) in the second repeat of the steps c) and e). Optionally a mixed adsorbent system may be used in one or more applications, e.g. mixed zirconium hydroxide / activated carbon. The process may further comprise subsequently treating the flexible material with a hydrophobic composition to render the surface hydrophobic. Such a hydrophobic composition may comprise, but not limited to, silicones, hydrocarbon-based finishes to include waxes and also repellency through structured effects i.e. nano finishes to create a lotus effect.

[0061] Optionally, the flexible material may have controlled surface characteristics (e.g. hydrophilic and / or hydrophobic characteristics). This may be achieved e.g. by treating at least part of the flexible material with e.g. a hydrophobic and / or hydrophilic treatment. One part of the flexible material may be treated with e.g. a hydrophobic treatment and another with e.g. a hydrophilic treatment.

[0062] The method may use a high shear mixer if it is intended to break up or reduce the particle size of the sorbent that is to be applied to the flexible substrate.

[0063] Thus, aspects of the disclosure are as listed below in the following numbered paragraphs.

[0064] 1. A protective material comprising a material, the material comprising: a barrier layer, and an outer layer, wherein the barrier layer comprises a flexible material substrate, at least one reactive sorbent and optionally a binder, and the reactive sorbent is loaded on the flexible material at 5 to 600 g / m2dry weight, preferably, the reactive sorbent is loaded on the flexible material at 30 to 600 g / m2dry weight; and wherein the outer layer comprises a fabric.

[0065] 2. A protective material as set out in paragraph 1, wherein no PF AS is intentionally added to the protective material. 3. A protective material as set out in either paragraph 1 or paragraph 2, wherein the barrier layer further comprises at least one further sorbent.

[0066] 4. A protective material as set out in paragraph 2, wherein the further sorbent comprises activated carbon, impregnated carbon, a resin, a zeolite and / or an additional reactive sorbent.

[0067] 5. A protective material as set out in any one of the preceding paragraphs, wherein the reactive sorbent and / or additional reactive sorbent comprises an oxide, hydroxide or oxyhydroxide of aluminum, silicon, magnesium, calcium, titanium, manganese, iron, cobalt, copper, zinc, hafnium and zirconium, a metal-organic framework material (MOF) or mixtures thereof.

[0068] 6. A protective material as set out in any preceding paragraph, wherein the reactive sorbent has a particle size in the range 0.05pm to 300 pm, preferably 1 pm to 200 pm, preferably 1 pm to 55 pm, more preferably 3 pm to 45 pm.

[0069] 7. A protective material as set out in any preceding paragraphs, wherein the flexible material substrate comprises a foam or a textile.

[0070] 8. A protective material as set out in paragraph 7, wherein the textile is selected from a knitted textile, a woven textile and a non-woven textile.

[0071] 9. A protective material as set out in either paragraph 7 or paragraph 8, wherein the textile is a knitted textile, optionally a pile knitted textile.

[0072] 10. A protective material as set out in any one of paragraphs 7 to 9, wherein the textile is made using a texturised yam. 11. A protective material as set out in any one of paragraphs 7 to 10, wherein the textile comprises a natural or synthetic textile or a combination of natural and synthetic.

[0073] 12. A protective material as set out in any one of paragraphs 7 to 11, wherein the textile comprises elastane.

[0074] 13. A protective material as set out in any one of the preceding paragraphs wherein the barrier layer and outer layer are joined.

[0075] 14. A protective material as set out in paragraph 13, wherein the barrier layer and outer layer are joined by mechanical joining, stitching, adhesive, and / or lamination.

[0076] 15. A protective material as set out in any one of the preceding paragraphs, wherein the outer layer comprises a fire-resistant material, optionally fire retardant nylon-cotton, or an aramid, optionally a meta-aramid.

[0077] 16. A protective material as set out in any one of the preceding paragraphs wherein the outer layer comprises a PFAS-free water repellent treatment.

[0078] 17. A protective material as set out in any one of the preceding paragraphs, further comprising an additional barrier layer, and / or a filtration layer.

[0079] 18. A protective material as set out in paragraph 17, wherein the filtration layer is disposed between the barrier layer and the outer layer.

[0080] 19. A protective material as set out in paragraph 18, wherein the filtration layer excludes particles of size 0.1 pm to 7 pm. 20. A protective material as set out in any one of the preceding paragraphs, further comprising a comfort liner.

[0081] 21. A protective material as set out in paragraph 20, wherein the comfort liner is disposed, optionally on the surface of the barrier layer, away from the outer layer.

[0082] 22. A protective material as set out in any one of paragraphs 17 to 21, wherein the barrier layer and a filtration layer, and optionally the comfort liner, are laminated together optionally using an adhesive.

[0083] 23. A protective material as set out in paragraph 22, wherein the barrier layer and a filtration layer, and optionally the comfort liner, are laminated together with an adhesive disposed, at least partially, between the barrier layer and the filtration layer, and optionally between the barrier layer and the comfort liner.

[0084] 24. A protective material as set out in either paragraph 22 or paragraph 23, wherein the adhesive comprises an adhesive web, adhesive powder, and / or a plurality of adhesive dots.

[0085] 25. A protective material as set out in paragraph 22 to paragraph 24, wherein the adhesive is a cross-linkable adhesive.

[0086] 26. A protective material as set out in any one of the preceding paragraphs, wherein the binder comprises a polymeric emulsion, optionally selected from an acrylic, a polyurethane, a natural rubber latex, chloroprene, styrene-butadiene rubber (SBR) and / or nitrile rubber, and optionally a colloid stabiliser and optionally a thickener.

[0087] 27. A protective material comprising a material, the material comprising: a first barrier layer, at least a second barrier layer, and an outer layer, wherein the first barrier layer comprises a flexible material substrate, at least one reactive sorbent and optionally a binder, and the reactive sorbent is loaded on the flexible material at 5 to 600 g / m2dry weight, the second barrier layer comprises a flexible material substrate, at least one (optionally different) sorbent and optionally a binder, and wherein the outer layer comprises a fabric.

[0088] 28. A process for production of a protective material, the process comprising: a) providing a flexible material, b) providing at least one PFAS-free sorbent dispersion comprising a binder and an amount of reactive sorbent, so that the reactive sorbent is to be loaded on the flexible material at 5 to 600 g / m2dry weight, preferably, the reactive sorbent is loaded on the flexible material at 30 to 600 g / m2dry weight, c) applying the sorbent dispersion to the flexible material to produce a treated flexible material, d) squeezing the treated flexible material under pressure, e) passing the pressed treated flexible material through a stenter, and f) optionally repeating any one of steps b), c), d) and / or e) to produce a barrier material, and g) disposing an outer layer on the barrier material.

[0089] 29. A process as set out in paragraph 28, wherein the sorbent dispersion further comprises a solvent, preferably water to provide a sorbent aqueous dispersion.

[0090] 30. A process as set out in either paragraph 28 or 29, wherein the impregnated flexible material is pressed at a predetermined pressure in the range 1 psi (6.9 kPa) to 150 psi (1 MPa), optionally 20 psi (138 kPa) to 100 psi (0.69 MPa), optionally 70 psi (0.48 MPa) to 100 psi (0.69 MPa).

[0091] 31. A process as set out in any one of the preceding paragraphs 28 to 30, wherein the sorbent dispersion has a viscosity in the range 40 cps to 4000 cps.

[0092] 32. A process as set out in any one of the preceding paragraphs 28 to 31, wherein the dispersion further comprises a polymeric thickener, a protective colloid, optionally a defoamer and / or a wetting agent.

[0093] 33. A process as set out in any one of the preceding paragraphs 28 to 32, wherein the binder comprises a polymeric emulsion, optionally selected from an acrylic, a polyurethane, a natural rubber latex, chloroprene, styrene-butadiene rubber (SBR) and / or nitrile rubber, and optionally a colloid stabiliser and optionally a thickener.

[0094] 34. A process as set out in any one of the preceding paragraphs 28 to 33, wherein the sorbent is loaded on the flexible material at 100 to 600 g / m2dry weight.

[0095] 35. A process as set out in any one of the preceding paragraphs 28 to 34, further comprising a step of treating the protective material with PFAS-free wetting modifier.

[0096] 36. A protective material as set out in any one of paragraphs 1 to 27, wherein the protective material is incorporated in a protective garment selected from a suit, a glove, a gauntlet, a mask, a gas mask, a sock, a head cover, trousers, a mitt and / or a jacket.

[0097] 37. A tent, gurney, decontamination wipe or mitt comprising at least a portion of a protective material as set out in any one of paragraphs 1 to 27. The textile may be treated with a PFAS-free wetting modifier to provide and / or modify wetting characteristics. If a water-repellent effect is required, then the finish can be tailored to provide this effect.

[0098] Examples of such finishes are silicones, hydrocarbon or structured effects i.e. nano finishes. The amount of finish to give this effect may be balanced with potential reduced reactivity of the adsorbent system. It may be desirable to have hydrophilic effect, and this can be achieved through the use of suitable polar hydrophilic finishes such as polyethylene glycol, polyvinyl alcohol etc.

[0099] Thus, applications where CWA protection can be provided with use of protective material according to the disclosure include tents, gurneys, decontamination wipes, socks, overboot covers, and / or mitts. The protective material may also be useful in filter applications such as masks and / or respirators and systems for filtration of air intakes

[0100] Other features and aspects of the disclosure may be as follows:

[0101] The filtration layer (aerosol barrier) may be to reduce or prevent direct ingress of airborne CWA. The airborne particles may be so small i.e. 0.3pm that they may penetrate through the garment and so protection is required against this form of threat. The aerosol barrier can be placed judiciously where it is deemed to provide the best protection. The aerosol layer may be a free-standing component but preferably may be laminated on to barrier or outer to maintain durability of this delicate component as discussed herein.

[0102] The textile structure of the flexible material substrate should be such that the amount of agent applied is held comfortably by the textile. Furthermore, the structure of the substrate may aid control of spreading of toxic chemicals / CWA by choice of construction or structure of the textile as well the individual fibres that make up the yarn, the textile may be woven, knitted and / or non-woven. Yarns with finer decitex per filament may be desirable. The yams may be continuous filament or made from staple yam. The cross section of individual filament may be controlled. The cross section of the yam may be of a round cross section to promote wicking through capillary action where bundles of filaments pack together to create channels. Alternatively, shaped cross sections are available, and will by themselves create channels within the yam and so promote wicking (e.g. a dog bone shape cross section) and / or mixed cross sections. The outer layer may be printed or coloured typically to provide camouflage and colours may have InfraRed Reflectance (IRR) capability, radar attenuation, and / or thermal attenuation.

[0103] In all aspects of the disclosure, preferably, no PF AS is intentionally added to the protective material, i.e. the protective material is preferably substantially PFAS-free.

[0104] Definitions

[0105] In this specification, unless the context otherwise suggests:

[0106] The term “powder” refers to any granule, microbead, or other geometric form less than about 1,000 pm in size, optionally less than about 300 pm in size, and optionally less than about 30 pm in size.

[0107] “Sorbent” refers to any porous material that may adsorb or absorb a toxic chemical (e.g. a chemical warfare agent) from a surface without necessarily any appreciable destruction / detoxification of toxic chemical.

[0108] “Reactive sorbent” refers to any material that may adsorb or absorb and detoxify an appreciable fraction, such as greater than about 25% by weight (or molar%) and preferably greater than about 50% by weight (or molar%), and more preferably greater than about 90% by weight (or molar%) of the toxic chemical after about 24 hours of contact.

[0109] “Impregnated carbon” refers to activated carbon that has been pre-treated with one or more impregnates to enhance its adsorption or filtering properties for particular applications. Impregnates may be deposited on to the carbon's surface or within its pores, and enhance the ability to remove specific contaminants from gases and / or liquids. Impregnates may include metal oxides (e.g. copper oxide or chromium oxide), metal salts (e.g. silver salts) to give a reactive impregnated carbon.

[0110] BRIEF DESCRIPTION OF THE DRAWINGS

[0111] Illustrative non-limiting embodiments of the present invention will be described in more detail with reference to the accompanying Figures, in which:

[0112] Figure 1 shows schematically a cross section of a swatch from material of a protective garment according to the invention. Figure 2 (a), and (b) shows embodiments schematically illustrating cross sections of swatches where the barrier layer is a layer of mixed sorbent (reactive sorbent and activated carbon); the outer layer in these embodiments is not laminated to the other layers.

[0113] Figure 3 (a), (b) and (c) shows embodiments schematically illustrating cross sections of swatches where the barrier layer is a layer of mixed sorbent (reactive sorbent and activated carbon).

[0114] Figure 4 (a) to (f) shows embodiments schematically illustrating cross sections of swatches where the reactive and non-reactive sorbent are two separate layers; the outer layer in these embodiments is not laminated to the other layers.

[0115] DETAILED DESCRIPTION OF THE INVENTION

[0116] Figure 1 shows a schematic cross section through a swatch of the material 2 of a protective material (e.g. a garment) according to the invention.

[0117] The material 2 comprises an outer layer 8 of textile which may be an inherently fire resistant textile, composed, for example, of aramid (e.g. meta aramid with a twill weave and weight around 280g / m2or Polyamide-imide, FR Viscose, Para-aramid, Polyamide 66, plain weave pattern weight of around 220g / m2) with a water repellent finish (e.g. silicone, waxes or hydrocarbon systems or e.g. a cationic dendrimer based water repellent treatment), which may be applied e.g. from aqueous solution by padding (impregnation). The water repellent composition may have a cross-linker. Control of water repellency (e.g. by adjusting concentration of the water repellent composition) is advantageous because it allows finer control over spreading of toxic chemicals (e.g. CWA) on the surface of the outer layer to control or reduce point overwhelming. A level of water repellency of 3 to 5 (according to AATCC TM 193, see below) may be useful.

[0118] The material 2 also comprises a barrier composite 4 comprising three layers.

[0119] The central layer of the barrier composite 4 is a barrier layer 6 comprising a flexible material substrate of a pile knitted polyester impregnated with a sorbent mixture of activated carbon and zirconium hydroxide (3 parts of zirconium hydroxide to 2 parts activated carbon by weight) and a binder of a self-crosslinking acrylic polymer dispersion (solids ratio by weight sorbent mixture: binder may be e.g. about 4: 1). The barrier layer may e.g. have a weight of about 400-500gsm (weight of the flexible material substrate and the sorbent), with the weight of textile of the order of 70gsm, and of the finish about 330 to 430gsm.

[0120] The layer of the barrier composite 4 between the barrier layer 6 and the outer layer 8 is a filtration layer 10 of an electrospun aerosol material (e.g. with filtration efficiency of 99% or 95% to 0.3 pm particles). Other aerosols-type materials may be used where there is a different filtration requirement e.g. filtration to larger particle of around 3 pm.

[0121] The third layer of the barrier composite 4, on the surface of the barrier layer 6 remote from the outer layer 8, is a comfort liner 12 of polyester textured weft knit (total weight around 55gsm, which includes adhesive glue spots). The choice of comfort liner 12 will be dictated by the end application. The comfort liner 12 provides comfort for the wearer when the garment is worn and preferably comprises elastane or has stretch characteristics. The comfort liner 12 preferably has a good cover factor so is less likely to allow adsorbent powder (which may, rarely, be shed from the barrier layer 6), to stain the wearer. The cover factor is preferably such that the porosity is below 6000 mm / s, optionally around 4600mm / s, at lOOPa, or lower. Porosity is an indicator of cover factor.

[0122] The filtration layer 10 may be disposed at other points in the barrier composite 4 or on the outer layer 8.

[0123] In the illustrated embodiment, the three layers of the barrier composite 4 are laminated and the outer layer 8 may be abutted to or joined to the barrier composite by e.g. sewing. The filtration layer 10 may be bonded to the barrier layer using an adhesive web (e.g. a thermoplastic co-polyamide based adhesive at 20g / m2). The comfort liner 12 may be bonded to the barrier layer 6 e.g. by the use of crosslinking glue spots (e.g. polyurethane PU-based).

[0124] Adhesive amounts may be in the range 1 to 50 gsm.

[0125] The material 2 described herein is in the form of a bilayer of an outer layer 8 / barrier composite 4 which has the advantage of improved conformability of the material. In other embodiments, the outer layer 8 and barrier composite 4 may be laminated together, which may improve the thermal burden of the final garment as there will be no air gaps between layers. To aid conformability, glue spots may be used to bond all layers. The use of a thermoset type adhesive is desirable as it aids durability of garment when subjected to any heat and also helps meet wash durability requirements.

[0126] Other embodiments of the disclosure are illustrated in Figures 2 to 4. Figure 2 shows embodiments schematically illustrating cross sections of swatches where the barrier layer is a layer of mixed sorbent as in Figure 1 (reactive sorbent and activated carbon); the outer layer in these embodiments is not laminated to the other layers; the embodiments have layers as follows: a) outer layer 8, aerosol layer 10, mixed sorbent layer 6, skin side comfort layer 12; and b) outer layer 8, mixed sorbent layer 6, aerosol layer 10, skin side comfort layer 12.

[0127] Figure 3 shows embodiments schematically illustrating cross sections of swatches where the barrier layer is a layer of mixed sorbent as in Figure 1 (reactive sorbent and activated carbon); the embodiments have layers as follows: a) outer layer 8 laminated to aerosol layer 10, a separate bilayer of the laminated mixed sorbent layer 6, skin side comfort layer 12; b) layers all laminated of outer layer 8, aerosol layer 10, mixed sorbent layer 6, skin side comfort layer 12; c) layers all laminated of outer layer 8, mixed sorbent layer 6, aerosol layer 10, skin side comfort layer 12.

[0128] Figure 4 shows embodiments schematically illustrating cross sections of swatches where the reactive and non-reactive sorbent are in two separate layers; the outer layer in these embodiments is not laminated to the other layers; the embodiments have layers as follows: a) outer 8, aerosol layer 10, activated carbon layer 14, reactive sorbent layer 6, skin side comfort layer 12; b) outer 8, activated carbon layer 14, aerosol layer 10, reactive sorbent layer 6, skin side comfort layer 12; c) outer 8, activated carbon layer 14, reactive sorbent layer 6, aerosol layer 10, skin side comfort layer 12; d) outer 8, aerosol layer 10, reactive sorbent layer 6, activated carbon layer 14, skin side comfort layer 12; e) outer 8, reactive sorbent layer 6, aerosol layer 10, activated carbon layer 14, skin side comfort layer 12.

[0129] Figure 4 (f) illustrates an embodiment with two reactive sorbent layers 6 and an activated carbon layer 14 as follows: outer 8, aerosol layer 10, first reactive sorbent layer 6, activated carbon layer 14, second reactive sorbent layer 6, skin side comfort layer 12. The position of the reactive sorbent layer(s) may be varied in the protective material.

[0130] Generally, in the embodiments illustrated in Figures 2 to 4, where layers are not laminated together, they will usually be attached e.g. by sewing or other mixing methods at parts of the material (e.g. at edges of panels etc.). Having bilayers (where not all layers are laminated) is useful because it may provide much improved thermal properties in e.g. a garment.

[0131] The present invention will now be described by way of example only with reference to the following non-limiting embodiments. Methods of producing the materials may be as set out in this disclosure and also in US 12,201,959, the disclosure of which is herein incorporated by reference in its entirety.

[0132] Impregnation (Dipping) of Adsorbent on Fabric

[0133] CBRN Clothing Application

[0134] For impregnation preferably any flexible material may be used providing it can hold an amount of the applied finish. “Flexible” in this context is one which will easily be processed on an impregnation or coating production line.

[0135] Impregnation or coating may be carried out using an aqueous based application method as this is a more environmentally friendly as it reduces or eliminates the use of VOCs. The principle of impregnation is that a finish (formulation or dispersion) is applied to a substrate where it may be uniformly distributed throughout the textile e.g. if the substrate is fully immersed in the finish. To control the amount that is present on the fabric, the fabric may go through a mangle or nip. The wet fabric passes between the two rolls under pressure which causes excess finish to be squeezed out (running off back into the trough of finish) and leaving a set amount on the fabric. The amount of finish that is on the fabric is quantified as a wet pick up and is a percentage value based on the weight of finish on the fabric and the weight of the fabric. The wet pick up, for a given formulation / finish, is primarily dictated by the substrate structure and the pressure applied; to a lesser extent the viscosity of the finish can also influence this parameter. The resulting treated substrate is dried in a set of one or more heating ovens - known as a stenter.

[0136] The concentration of the finish and the wet pick up determines the amount of overall solids that are applied in the process to the substrate. If there was insufficient adsorbent applied through a single pass, then the treated fabric may be put through the process again i.e. a second pass to apply more. A number of passes may be useful.

[0137] In more complex processes, each pass may differ, and this may result in a layered application. Determining the wet pick up and the applied solids allows an optimized formulation to be applied. Very high solids application on a substrate cannot always be achieved in a single pass and so multiple passes may be required. A starting formulation may be provided which can be adjusted to accommodate various applications- see Formulation Fl in Tables 1 and 2.

[0138] The ratio of binder system to the adsorbent is important in controlling the rates of these sorption processes. In the starting formulation given for every 1 part by weight of binder 3.8 parts by weight of zirconium hydroxide is used. This provides a reasonable level of durability with very little or no shedding taking place.

[0139] Another factor is the particle size of the adsorbent. Larger particle sizes have a ratio of surface area to volume smaller than smaller particles. This means that for a given amount of material it may be better to have larger particle as less of the bulk of the material is contacted by the binding system. There will be a compromise on particle size dependent upon the application technique being used and the nature of the adsorbent.

[0140] An important aspect when considering binder levels is that the additional or auxiliary components in the formulation can influence the binder solids content. For example, if a binder is used and e.g. a polymeric thickener then the polymer thickener solids will contribute towards the binding capacity.

[0141] Depending upon the nature of the adsorbent system and how prone it is to sedimentation then a thickening agent may be required, to ensure that the adsorbent remains suspended for a sufficient length of time to prevent settling and so avoid inconsistent application.

[0142] The filling of the pores is an issue as it prevents or reduces the likelihood that other components enter and block the pores, thus a polymeric wetting agent with a large molecular weight may be used. The act of drying (during stentering) is believed to result in the evaporation of the water out of the pores helping breakthrough of any film forming material to allow these pores to be accessible again. The term wetting agent and dispersing agent are used interchangeably herein.

[0143] For some adsorbents, a wetting agent is not required as they will readily wet out in water e.g. if they are hydrophilic in nature. Generally, inorganics will tend to wet out relatively easily without the aid of a wetting agent. In the examples, zirconium hydroxide can be incorporated quite effectively without the use of a wetting agent. The adsorbent may be of a particular particle size depending upon the application technique and also textile being used. Generally, for pad application the particle size may be less than 100 microns and preferably at or below 45 microns. Having smaller particle size than 45 microns is desirable from an application point of view but a comprise has to be reached as potentially pore volume properties will be compromised for certain adsorbents.

[0144] Smaller particle sizes will aid creating a good suspension less likely to settle out. Adsorbents with high densities can be dispersed this way. The adsorbent can be supplied already as a ground powder which is ready for dispersing.

[0145] The first step in the process is to incorporate the adsorbent in water; depending upon the nature of the adsorbent a wetting agent may be required to effectively incorporate it into the water. Generally inorganic adsorbents are readily dispersible in water as they may be generally polar and hydrophilic in nature. The wetting agent can be selected from a wide range that are generally available. Good wetting characteristics are achieved e.g. through the use of a sodium salt of a polymeric naphthalene sulphonate. These are particularly good at dispersing organic material which may be hydrophobic in nature. Dispersing agent not only wet out but produce a charged system to reduce the propensity for agglomeration to take place.

[0146] The amount used will be enough to ensure the adsorbent can be effectively wetted and dispersed. Wetting agent could be fugitive in nature - small molecules such as IPA are common but other systems are available.

[0147] The choice of stirrer may affect incorporation of the adsorbent. A traditional propellor type stirrer may be used for mixing. A high shear stirrer may be used. A high shear stirrer may be used to good effect to reduce the particle size if the starting material is too coarse for the application; the resulting reduced particle size adsorbent system may then be used in a propellor mixing system for the remainder of the formulation.

[0148] High shearing for certain adsorbents can be advantageous in controlling the viscosity of the mix and in keeping the adsorbent suspended.

[0149] Protective colloids may be used. This may be useful where the adsorbent is particularly active. An example would be activated carbon where the surface is active and adsorbs organic molecules readily. If a binder were to be added directly to a dispersion of the activated carbon then coagulation / flocculation of the system may take place. Protective colloids are ideally large molecules which reduces the propensity for them entering the pores of the adsorbent but also provides steric hindrance to prevent agglomeration taking place. Examples of colloid stabilizers are carboxy methyl cellulose, methyl cellulose, hydroxy propyl methyl cellulose, Xanthan gum, polyvinyl alcohols, etc, and mixtures thereof.

[0150] The ideal amount of a colloid stabilizer may be established by trial and error; generally adding a known amount and then checking to see if coagulation take place on addition of the binder system. The addition of the colloid stabilizer may help in controlling the viscosity; in this context it will help in maintain a low viscosity for ease of mixing. The amount of the protective colloid used, may help control the overall viscosity. After the addition of the colloid stabilizer it is generally desirable to leave stirring for a given length of time, for example 15 minutes, to ensure good stabilization.

[0151] As mentioned previously the end application may dictate the components used in the formulation.

[0152] The binder can be added next, slowly. The binders would typically be an emulsion polymer - be it synthetic or natural although a binding system based on a dispersion can also be used. The binder can be a variety of systems, for example, acrylic, polyurethane, natural rubber latex, nitrile etc. The function of the binder is to bind the adsorbent to the substrate. In general, the more durable the adsorbent needs to be adhered to the textile the more binder is required. If the durability is less of a concern then the amount of binder can be reduced.

[0153] The binder (and the protective colloid) can affect the handle of the material so a softer film forming emulsion would give a more conformable product.

[0154] Depending upon the particle size of the adsorbent used it may be that the resulting suspension is adequately stable with no sedimentation taking place in which case it is ready for application. If the particles are coarse or the dispersed adsorbent has the propensity to settle then a thickener may be used. There are a variety of thickeners that can be used to thicken up water-based systems. An alkali swellable thickener is particularly suitable. Ammonia may be added to the formulation to ensure an appropriate alkalinity and has the advantage that it is fugitive in nature when exposed to heat returning system to its original pH.

[0155] Sedimentation can be assessed using a spatula to check if there is any sedimentation after a given length of time. The rate of sedimentation should reflect the process in which the system is to be used and so the viscosity and the amount of thickener can be adjusted accordingly. Having no sedimentation for around Ihr is a reasonable test. By using a combination of viscosity control and additional production stirring / agitation one can prevent sedimentation taking place in the production environment. Once the dip is prepared it is ready to be applied to a textile substrate by impregnation. Different adsorbents can be applied in different passes - formulation F4 shows a carbon only adsorbent formulation that can be applied so a layered system can be generated. Formulation F5 & F7 represents mixed adsorbent systems with activated carbon and zirconium hydroxide intimately mixed at different ratios i.e. blended application.

[0156] Some adsorbent systems, once dried, will become slightly hydrophobic in nature. This may cause a potential issue for any subsequent impregnation as the finished fabric may not absorb / wet out effectively when immersed in a formulation. In order to overcome this issue a wetting agent may be added in the adsorbent formulation to aid wetting of hydrophobic surface. Examples may be fugitive wetting agent such as IPA or other suitable materials for example alcohol polyglycol ether.

[0157] The textile may be more absorbent through the use of textured yam and or through construction of the textile. Having a hydrophilic finish on the textile will also help with wetting out of the textile and improved absorption. Textiles may be a knitted, woven, or nonwoven. A non-textile material such as foam could also be used as this provides a porous substrate to hold on to the sorbent.

[0158] A suitable textile may be a knitted pile fabric which has loops of yarn which create bulk. The textile may be of synthetic or natural yarns or mixed depending upon the requirements of the end application. Double pile fabrics are particularly advantageous. Other textiles such as nonwovens may be used. Textiles or substrates may have stretch which will lead to more conformable material if required. Knitted structures containing elastane would be suitable although stretch can be introduced through construction of the textile (e.g. pattern used) and use of textured yarns alone; this can further be supplemented with the use of an elastane in the structure. Woven structures with textured yarns may be supplemented with the presence of an elastane to improve the stretch characteristics. The application of the dispersion results in a treated textile.

[0159] Application of up to around 600gsm of solids formulation may be useful. The textile can be treated to provide appropriate wetting characteristics. If a water-repellent effect is required then the finish can be tailored to provide this effect. Examples of such finishes are silicones, hydrocarbon or structured effects i.e. nano finishes. The amount of finish to give this effect must be balanced with the fact that such finishes can cause reduced reactivity of the adsorbent system. It may be desirable to have hydrophilic effect and this can be achieved through the use of suitable polar hydrophilic finishes such as polyethylene glycol, polyvinyl alcohol etc.

[0160] Mixed adsorbents (e.g. reactive sorbent and activated carbon) may be used, and further functionalization to enhance the reactivity can be employed. A layered system can also be created where the same or different adsorbents / sorbents are applied at each pass.

[0161] The barrier layer comprises a fabric with a formulation of an active sorbent applied thereto.

[0162] A barrier material may comprise at least two distinct layers comprising a first reactive sorbent layer and a second non-reactive sorbent layer. A formulation base based on Fl can be applied to textile to generate fabric with 5 to 300g / m2and used in conjunction with an activated carbon impregnated fabric with a carbon loading of between 5 to 500g / m2using a formulation based around F4.

[0163] Formulations were prepared and applied to samples of a fabric. Table 1 describes the preparation of formulation Fl and the composition of each formulation is described in table 2, below. No polyfluoroalkyl substances (PF AS) were added to the fabric, nor to the binder nor to the formulations.

[0164] The fabric was a knitted pile fabric with the construction as follows:

[0165] In the formulations:

[0166] Fl - Base starting formulation - Zirconium Hydroxide F4 - Standard formulation for activated carbon with D95 45microns

[0167] F5 - Thickened formulation containing a mixture of adsorbents - activated carbon & Zirconium Hydroxide

[0168] F7 - Thickened formulation containing a mixture of adsorbents - activated carbon & zirconium hydroxide with inclusion of wetting agent.

[0169] Examples 1 to 8

[0170] Chemical Warfare Agent (CWA) Testing

[0171] Reactive and Sorbent & Unreactive Sorbent as an Intimate Mixture For Garment

[0172] Materials were formed generally as described and illustrated according to Figure 1, above. Swatches were cut from the materials and tested as set out below.

[0173] Examples 1 to 4 had an outer layer of a base fabric made from 100% meta aramid fibre, twill weave pattern and weight around 280g / m2. Examples 5 to 8 has an outer layer of a base fabric made from 32% Polyamide-imide, 38% FR Viscose, 20% Para-aramid, 9% Polyamide 66, 1% antistatic, plain weave pattern weight of around 220gsm. Fabric was printed.

[0174] The outer layers were treated with a water repellency coating of hyperbranched and linear polymers, cationic, pH value approx. 3.5 - 5.5, easily dilutable with cold water.

[0175] The examples were tested for water repellency according to AATCC TM 193 - Test Method for Aqueous Liquid Repellency wherein drops of standard test liquids, consisting of IP A (isopropyl alcohol) solutions with varying surface tensions, are placed on the fabric surface and observed for wetting, wicking and contact angle. The aqueous repellency grade is the highest numbered test liquid which does not wet the fabric surface. (The scale ranges from zero to eight, with eight signifying the most repellent surface.).

[0176] The examples were tested for CWA efficacy according to AEP 38. All examples passed.

[0177] The results for water repellency and CWA efficacy are described in Table 3 below before and after 10 launderings. The inventions show that excellent results may be achieve for protective garments without the use of fluorocarbon / PF AS based technology.

[0178] In addition to protective garments, materials according to the disclosure may be used in other applications e.g. tent covers, gurneys etc. Reactive Sorbent and Non-reactive Sorbent as Separate Lavers e.g for use as Garments

[0179] In Examples 9 to 11, a layer of reactive sorbent impregnated textile and a separate non- reactive sorbent impregnated textile layer were used and in these embodiments, laminated together. The reactive sorbent layer comprises a textile loaded with zirconium hydroxide using a formulation based on formulation Fl with a typical loading of 130g / m2dry sorbent.

[0180] Activated carbon i.e. the non-reactive sorbent system has been applied to a separate textile using a formulation based on F4 to achieve a typical dry sorbent formulation loading of around 120g / m2.

[0181] The lamination of these two layers has been achieved using a thermoplastic co-polyamide adhesive web at weight of 20g / m2.

[0182] Laminations are typically carried out at around 150°C with a dwell time of around 90 seconds depending on adhesive system. However, conditions may vary depending upon equipment being used. A target adhesion of greater than 0.5N / cm is aimed for.

[0183] In these examples, as the activated carbon sorbent layer may be next to the skin in garments when worn, a comfort liner was added to the laminated layers. The comfort liner was a layer of a polyester knitted textile with a plurality of thermoplastic glue spots applied to allow the textile to be easily laminated and provide flexibility. The knitted glue spotted fabric is typically around 55g / m2weight.

[0184] The outer fabric is an aramid-based fabric selected for good physical properties and, importantly, inherent flame-retardant properties.

[0185] In these examples the woven fabric has the following composition 32% Polyamide-imide, 38% FR Viscose, 20% Para-aramid, 9% Polyamide 66 & 1% anti-static, approximately 220g / m2

[0186] The textiles were impregnated with a PFAS-free durable water repellent (DWR) coating of hyperbranched and linear polymers, cationic, pH value approx. 3.5 - 5.5 (dilutable with cold water). The repellency achieved (determined using AATCC TM 193) gives a good repellency of 5 in our testing. In these examples, the outer was not laminated to the other layers (i.e. the material was a bilayer). Total composite weight is around 720g / m2, air permeability of around 80mm / s at 100 Pa and a gauge of around 2.1mm.

[0187] The material was tested against GD, HD & VX according to NATO AEP 38 test methodology for laid droplet diffusive flow for HD & GD, and LVAP (Low Volatility Agent Permeation) for VX. The results indicated that the tests were passed with no breaching taking place i.e. no CWA has passed through the material at the limit of detection.

[0188] Thus, protective materials with separate reactive and unreactive sorbent textile layers have been demonstrated as conclusively passing CWA testing without the use of any PF AS components.

[0189] 100 23,2

[0190] • Addition of colorant e.g. carbon black can be desirable if a white looking textile is undesirable.

[0191] Table 1: Preparation of formulation 1, no polyfluoroalkyl substances (PFAS) were added to the formulation.

[0192]

[0193] ZOH refers to zirconium hydroxide

[0194] Table 2. Composition of formulations Fl, F4, F5 and F7. No polyfluoroalkyl substances (PFAS) were added to the formulations.

[0195] Table 3. CWA test results where the reactive sorbent and unreactive sorbent are mixed and applied to the textile

[0196]

[0197] *Below limit of detection

[0198] Table 4. CWA test results where the protective material comprised a separate reactive sorbent layer and a non-reactive sorbent layer as two separate components (using the arrangement generally shown in Fig. 4d, but with no aerosol layer).

[0199] All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described methods and system of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.

Claims

CLAIMS1. A protective material comprising: a barrier layer, and an outer layer, wherein the barrier layer comprises a flexible material substrate, at least one reactive sorbent and optionally a binder, and the reactive sorbent is loaded on the flexible material at 5 to 600 g / m2dry weight, preferably the reactive sorbent is loaded on the flexible material at 30 to 600 g / m2dry weight, and wherein the outer layer comprises a fabric.

2. A protective material as claimed in claim 1, wherein no PF AS is intentionally added to the protective material.

3. A protective material as claimed in either claim 1 or claim 2, wherein the barrier layer further comprises at least one further sorbent.

4. A protective material as claimed in claim 2, wherein the further sorbent comprises activated carbon, impregnated carbon, a resin, a zeolite and / or an additional reactive sorbent.

5. A protective material as claimed in any one of the preceding claims, wherein the reactive sorbent and / or additional reactive sorbent comprises an oxide, hydroxide or oxyhydroxide of aluminum, silicon, magnesium, calcium, titanium, manganese, iron, cobalt, copper, zinc, hafnium and zirconium, a metal-organic framework material (MOF) or mixtures thereof.

6. A protective material as claimed in any preceding claim, wherein the reactive sorbent has a particle size in the range 0.05pm to 300 pm, preferably 1 pm to 200 pm, preferably 1 pm to 55 pm, more preferably 3 pm to 45 pm.

7. A protective material as claimed in any preceding claims, wherein the flexible material substrate comprises a foam or a textile.

8. A protective material as claimed in claim 7, wherein the textile is selected from a knitted textile, a woven textile and a non-woven textile.

9. A protective material as claimed in either claim 7 or claim 8, wherein the textile is a knitted textile, optionally a pile knitted textile.

10. A protective material as claimed in any one of claims 7 to 9, wherein the textile comprises a textured yarn.

11. A protective material as claimed in any one of claims 7 to 10, wherein the textile comprises a natural or synthetic textile or a combination of natural and synthetic.

12. A protective material as claimed in any one of claims 7 to 11, wherein the textile comprises elastane.

13. A protective material as claimed in any one of the preceding claims wherein the barrier layer and outer layer are joined.

14. A protective material as claimed in claim 13, wherein the barrier layer and outer layer are joined by mechanical joining, stitching, adhesive, and / or lamination.

15. A protective material as claimed in any one of the preceding claims, wherein the outer layer comprises a fire resistant material, optionally fire retardant nylon-cotton, or an aramid, optionally a meta aramid.

16. A protective material as claimed in any one of the preceding claims wherein the outer layer comprises a PFAS-free water repellent treatment.

17. A protective material as claimed in any one of the preceding claims, further comprising a filtration layer.

18. A protective material as claimed in claim 17, wherein the filtration layer is disposed between the barrier layer and the outer layer.

19. A protective material as claimed in claim 18, wherein the filtration layer excludes particles of size 0.1 pm to 7 pm.

20. A protective material as claimed in any one of the preceding claims, further comprising a comfort liner.

21. A protective material as claimed in claim 20, wherein the comfort liner is disposed on the surface of the barrier layer away from the outer layer.

22. A protective material as claimed in any one of claims 17 to 21, wherein the barrier layer and a filtration layer, and optionally the comfort liner, are laminated together with an adhesive.

23. A protective material as claimed in claim 22, wherein the barrier layer and a filtration layer, and optionally the comfort liner, are laminated together with an adhesive disposed, at least partially, between the barrier layer and the filtration layer, and optionally between the barrier layer and the comfort liner.

24. A protective material as claimed in either claim 22 or claim 23, wherein the adhesive comprises an adhesive web, adhesive powder and / or a plurality of adhesive dots.

25. A protective material as claimed in any one of claims 22 to claim 24, wherein the adhesive is a cross-linkable adhesive.

26. A protective material as claimed in any one of the preceding claims, wherein the binder comprises a polymeric emulsion, optionally selected from an acrylic, a polyurethane, a natural rubber latex, chloroprene, styrene-butadiene rubber (SBR) and / or nitrile rubber, and optionally a colloid stabiliser and optionally a thickener.

27. A process for production of a protective material, the process comprising: a) providing a flexible material, b) providing at least one PFAS-free sorbent dispersion comprising a binder and an amount of reactive sorbent, so that the reactive sorbent is to be loaded on the flexible material at 5 to 600 g / m2dry weight, preferably, the reactive sorbent is to be loaded on the flexible material at 30 to 600 g / m2dry weight, c) applying the sorbent dispersion to the flexible material to produce a treated flexible material, d) squeezing the treated flexible material under pressure, e) passing the pressed treated flexible material through a stenter, and f) optionally repeating any one of steps b), c), d) and / or e) to produce a barrier material, and g) disposing an outer layer on the barrier material.

28. A process as claimed in claim 27, wherein the sorbent dispersion further comprises a solvent, preferably water to provide a sorbent aqueous dispersion.

29. A process as claimed in either claim 27 or 28, wherein the impregnated flexible material is pressed at a predetermined pressure in the range 1 psi (6.9 kPa) to 150 psi (1 MPa), optionally 20 psi (138 kPa) to 100 psi (0.69 MPa), optionally 70 psi (0.48 MPa) to 100 psi (0.69 MPa).

30. A process as claimed in any one of the preceding claims 27 to 29, wherein the sorbent dispersion has a viscosity in the range 40 cps to 4000 cps.

31. A process as claimed in any one of the preceding claims 27 to 30, wherein the dispersion further comprises a polymeric thickener, a protective colloid, a defoamer, and / or a wetting agent.

32. A process as claimed in any one of the preceding claims 27 to 31, wherein the binder comprises a polymeric emulsion, optionally selected from an acrylic, a polyurethane, a natural rubber latex, chloroprene, styrene-butadiene rubber (SBR) and / or nitrile rubber, and optionally a colloid stabiliser and optionally a thickener.

33. A process as claimed in any one of the preceding claims 27 to 32, wherein the sorbent is loaded on the flexible material at 100 to 600 g / m2dry weight.

34. A process as claimed in any one of the preceding claims 27 to 33, further comprising a step of treating the protective material with PFAS-free wetting modifier.

35. A protective material as claimed in any one of claims 1 to 26, wherein the protective material is incorporated in a protective garment selected from a suit, a glove, a gauntlet, a mask, a gas mask, a sock, a head cover, trousers, a mitt and / or a jacket.

36. A tent, gurney, decontamination wipe or mitt comprising at least a portion of a protective material as claimed in any one of claims 1 to 26.

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