Protective textile materials

Abstract

There is disclosed a protective material comprising a treated fabric. The treated fabric has solid particles dispersed between its fibres to increase inter-fibre friction.

Description

[0001] PROTECTIVE TEXTILE MATERIALS

[0002] Field This specification concerns protective materials, specifically puncture-resistant fabrics and methods for preparing such puncture-resistant fabrics.

[0003] Background Protective materials offer shielding against sharp or jagged objects and are used in many applications including making safety gloves (or personal protective equipment (PPE) more generally), vehicle tyres and armour. For example, safety gloves comprising such materials are widely worn by Waste Management workers to mitigate the risk of injures as a result of broken glass exposure. well-known example of a protective material is Kevlar (para-Aramid), which is a strong synthetic fibre which can be woven into fabrics for use in gloves, tyres etc., or as components in composite materials such as armour etc. The extent of protection, e.g. cut protection, offered by the fabric can be tailored using different weave patterns. Further, such materials are thin, lightweight and offer good dexterity to the user when used in safety gloves. However, such fabric materials are susceptible to punctures from very thin objects such as needles or some glass shards. Protective materials have been developed to provide increased punctureresistance. For example, materials comprising layers of epoxy platelets offer high levels of puncture-resistance. However, the epoxy platelets in a given layer are connected by unprotected seems to allow flexibility of the material, such that multiple layers of epoxy platelets must be stacked and overlapped to cover the unprotected regions. Such epoxy platelet solutions therefore have increased size and weight, which can compromise the functionality and application of the protective material. For example, safety gloves comprising such materials offer less dexterity to the user. Aspects of the present invention seek to provide a protective material that addresses the foregoing.

[0004] Summary

[0005] According to an aspect of the present invention, there is provided a protective material comprising a treated fabric, wherein the treated fabric has solid particles dispersed between its fibres. This may be to increase inter-fibre friction. With increased inter-fibre friction, it is harder to move and separate fibres of the fabric to define a space through which an object can penetrate the fabric. Accordingly, the protective material of the present invention has increased puncture resistance. This enhances the performance of many fabric-based protective materials such as Kevlar (para-Aramid). Further, in an initial study, the protective material of the present invention out-performs epoxy platelet protective materials with respect to needle puncture-resistance.

[0006] The fabric may be a Kevlar fabric or an Aramid fabric generally. Kevlar and Aramid are strong and lightweight materials, such that their use in the present invention may enhance cut-resistance (not only puncture resistance) of the protective material without a large weight sacrifice.

[0007] The fabric may be a non-woven (e.g. a felt) fabric. That is, the fibres may be neither woven nor knitted but instead bonded together by chemical, mechanical, heat or solvent treatment. In that regard, it has been found that a non-woven fabric is particularly advantageous for needle puncture resistance in that its fibres may be harder to separate under the force of the needle. This may be on account of the fibres having a less regular pattern such that there are less ordered gaps (spaces) for a needle to push therethrough. The needle may tend to snag on the fibres.

[0008] The fabric may be a wettable fabric having a contact angle of 90 degrees or less. The fabric, e.g. its fibres, may also or instead comprise a hydrophilic coating. The solid particles may be nanoparticles. That is, some or all of the nanoparticles may each have a total span or total diameter under 100 nanometers. The use of nanoparticles, which are typically smaller than the diameter of individual fibres in the fabric, may enable solid particles to more easily locate themselves between individual fibres. That is to increase the degree of infiltration.

[0009] In that regard, in embodiments the solid particles may have a span or diameter which is smaller than the diameter of individual fibres in the fabric.

[0010] The solid particles may be ceramic particles.

[0011] Ceramics are hard, heat-resistant and corrosion-resistant materials. Accordingly, the use of such particles may not only increase inter-fibre friction but also offer an obstruction to prevent or retard the motion of an object through the fabric.

[0012] The ceramic particles may include particles of any one or more of the following materials: Silica, Alumina, and Titania.

[0013] The fabric may be a Kevlar (Aramid) Felt and the solid particles are selected from one of: Zirconia, Tin(IV) Oxide and Titanium Dioxide.

[0014] The treated fabric may be at least partly encapsulated within a polymer matrix.

[0015] This may be advantageous to stabilise the solid particles within the treated fabric, thereby making it more durable, reducing wear and tear etc.

[0016] The polymer matrix may comprise Silicone. The polymer matrix may be a Silicone rubber.

[0017] Silicone may improve the temperature resistance and chemical resistance of the material. According to another aspect of the present invention, there is provided a protective article, e.g. a safety glove, comprising the protective material as described herein.

[0018] According to another aspect of the present invention, there is provided a method for preparing a protective material, the method comprising: providing a (e.g. raw or untreated) fabric; and forming a treated fabric by providing solid particles between fibres of the fabric. According to another aspect of the present invention, there is provided a method for preparing a protective material, the method comprising: providing a (e.g. raw or untreated) fabric; and forming a treated fabric by: infusing the fabric with a slurry of solid particles suspended in a liquid matrix; and removing the liquid matrix to leave the solid particles dispersed between the fibres of the fabric.

[0019] The slurry may comprise solid particles in an amount of at least 1 %, e.g. at least 30%, by total volume or by total weight of the slurry. This may be advantageous in that it provides a minimum loading and thus minimum areal density of solid particles in the protective material.

[0020] The slurry may comprise solid particles in an amount of at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70% or at least 75% by total volume or by total weight of the slurry.

[0021] The slurry may comprise solid particles in an amount of approximately 50% by total volume or by total weight of the slurry. This may be advantageous in that it provides an optimum loading of solid particles in the protective material, to increase needle puncture-resistance while maintaining dexterity.

[0022] With respect to loading of solid particles in the protective material, in embodiments the protective material may comprise solid particles in an amount of at least 10%, at least 15%, at least 20%, at least 25% at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70% or at least 75% by total volume or by total weight of the treated fabric. The protective material may comprise solid particles in an amount of approximately 50% by total volume or by total weight of the treated fabric.

[0023] It will be appreciated that by using the above loadings of solid particles in the slurry or protective material, the invention may increase the extent by which the protective material inhibits the spread of fibres and thus prevents sharp objects (needles or, e.g., objects with outer diameter or span less than 2mm or 14 or more on the Birmingham scale) passing therebetween and penetrating the fabric. This is in contrast to hypothetical arrangements where lower loadings of solid particles may be used to provide resistance to bulk impact forces (e.g. from large objects travelling at high speed), but provide little protection against comparatively smaller objects such as needles which may be able to force their way between fibres.

[0024] The liquid matrix may be water. An aqueous solution may be advantageous in that it is more environmentally sustainable.

[0025] The slurry may have been (e.g. is) selected or pre-prepared to have a specific loading or concentration (e.g. percentage by total volume or percentage by total weight of the slurry) of solid particles which has been predetermined to correspond to, i.e. yield, a predefined loading or areal density of solid particles in the treated fabric.

[0026] The liquid matrix may be removed by drying or curing.

[0027] The method may further comprise a step of encapsulating the treated fabric within a polymer matrix.

[0028] According to another aspect of the present invention, there is provided a method of preparing a protective article, comprising: providing a protective material comprising a treated fabric having solid particles dispersed between its fibres to increase inter-fibre friction, wherein the treated fabric is at least partly encapsulated within a (e.g. Silicone) polymer matrix (e.g. a Silicone rubber); and manipulating the protective material into the form (e.g. shape) of the final protective article.

[0029] According to another aspect of the present invention, there is provided a method of preparing a protective article, comprising: providing a (e.g. raw or untreated) fabric; forming a treated fabric by: infusing the fabric with a slurry of solid particles suspended in a liquid matrix; and removing the liquid matrix to leave the solid particles dispersed between the fibres of the fabric; wherein the method further comprises: encapsulating the treated fabric within a polymer matrix (e.g. a Silicone rubber); and manipulating the protective material into the form (e.g. shape) of the final protective article.

[0030] According to another aspect of the present invention, there is provided a method of preparing a protective article, comprising: providing a protective material comprising a treated fabric having solid particles dispersed between its fibres to increase inter-fibre friction; and manipulating the protective material (i.e. the treated fabric) into the form (e.g. shape) of the final protective article. The method may further comprise encapsulating all or part of the protective material (i.e. the treated fabric) within a polymer matrix after the step of manipulating the protective material (i.e. the treated fabric) into the form of the final protective article. According to another aspect of the present invention, there is provided a method of preparing a protective article, comprising: preparing a protective material by providing a (e.g. raw or untreated) fabric; and forming a treated fabric by: infusing the fabric with a slurry of solid particles suspended in a liquid matrix; and removing the liquid matrix to leave the solid particles dispersed between the fibres of the fabric; and manipulating the protective material (i.e. the treated fabric) into the form

[0031] (e.g. shape) of the final protective article.

[0032] The method may further comprise encapsulating all or part of the protective material (i.e. the treated fabric) within a polymer matrix after the step of manipulating the protective material (i.e. the treated fabric) into the form of the final protective article.

[0033] According to another aspect of the present invention, there is provided a method for preparing a protective article, comprising in turn the steps of: providing a raw fabric material; manipulating the raw fabric material into the form of the protective article; infusing (e.g. impregnating) the raw fabric material with a slurry of solid particles suspended in a liquid matrix; and removing the liquid matrix to leave behind a treated fabric having solid particles dispersed between its fibres.

[0034] The method may further comprise encapsulating all or part of the treated fabric within a polymer matrix. The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects may be applied to any other aspect. Furthermore, except where mutually exclusive, any feature described herein may be applied to any aspect and / or combined with any other feature described herein.

[0035] Brief Description of the Drawings

[0036] Embodiments of the invention will now be described by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 is a diagram schematically illustrating a conventional safety glove falling within the state of the art;

[0037] Figure 2 is a diagram schematically illustrating a safety glove comprising a protective material in accordance with an embodiment of the present invention;

[0038] Figure 3 is a bar graph which illustrates the force required for a needle to penetrate the protective material of the present invention; Figure 4 is a diagram schematically illustrating a further embodiment of the protective material of the present invention; and

[0039] Figure 5 is a flow chart illustrating a method of preparing the protective material of the present invention.

[0040] Like reference numerals are used throughout the drawings to refer to like features of the invention.

[0041] Detailed Description

[0042] Figure 1 is a diagram which schematically illustrates a conventional protective article, specifically a safety glove 100 which falls within the state of the art.

[0043] The safety glove 100 has a structure which comprises at least one layer of a protective fabric 101 such as Kevlar. In the illustrated embodiment, the fabric 101 is a woven fabric which comprises a first set of Kevlar fibres 102 and a second set of Kevlar fibres 103 which are woven together by interlacing the first set of Kevlar fibres 102 and the second set of Kevlar fibres 103 at right angles to one another. While fabric materials provide some cut-resistance, owing to the strength of the fibres themselves, fabrics are susceptible to punctures from very sharp or thin objects, such as the needle 104 shown in Figure 1. In that regard, the needle 104 comprises a body which tapers towards a pointed end 105 which is thin enough to be received in the interstitial spaces 106, 107 between adjacent fibres 102, 103. As the pointed end 105 engages the fabric 101 (as denoted by the arrow 108), the tapered profile will cause the fibres 102, 103 to slide over one another so as to increase the interstitial spaces 106, 107 between them, thereby allowing the needle 104 through the fabric 101. The present invention addresses this problem by providing a protective material which has increased puncture-resistance and is therefore particularly suitable for use in protective articles.

[0044] Figure 2 is a diagram which schematically illustrates a protective article in accordance with an embodiment of the present invention. The protective article is in the form of a safety glove 200, which offers cut and puncture resistance.

[0045] The safety glove 200 has a structure which comprises at least one layer of a protective material in accordance with the present invention. As will be described in further detail below, the protective material comprises a fabric 201 which has been treated with solid particles.

[0046] In the illustrated embodiment, the fabric 201 is woven in that it comprises a first set of parallel fibres 202 and a second set of parallel fibres 203 which are interlaced at substantially right angles to one another. A woven pattern may be advantageous in that the tight interlocking of fibres provides a stronger fabric which is resistant to cutting. However, it will be appreciated that any form of fibrebased fabric can instead be used in the present invention. The fabric 201 may be, for example, a non-woven (e.g. felt) fabric, or a webbed fibre structure.

[0047] The fabric 201 may have any type of fibres 202, 203, which may be selected based on a number of factors such as the desired strength of the protective material. In the present embodiment, the fibres 202, 203 are Kevlar fibres and the fabric 201 is a commercial-off-the-shelf (COTS) woven Kevlar fabric sheet manipulated into the final form of the safety glove 200. In other embodiments however, the Kevlar fibres may be non-woven.

[0048] Kevlar fibres have a high tensile strength-to-weight ratio and maintains its strength across a wide temperature range. Other suitable fabrics comprise Aramid fibres. It will be appreciated here that while embodiments are described with reference to using Aramid fibres such as Kevlar, any type of fibre can be used. Fabrics with high tensile strength may be particularly advantageous in that they offer greater impact and puncture resistance.

[0049] The Applicant has found the following materials to be particularly effective COTS examples of a fabric to be used in the present invention for providing resistance to puncture by needle-like objects:

[0050] • ultra-high-molecular-weight polyethylene (LIHMWPE), e.g. Spectra® material;

[0051] • Polyamide;

[0052] • Nylon;

[0053] • Dyneema® and Lycra®; and

[0054] • Aramid (Kevlar®).

[0055] As shown in Figure 2, the fabric 201 has been treated so as to infuse and disperse solid particles 204 throughout the fabric 201 , including the interstitial spaces 206, 207 between fibres 202, 203. The solid particles 204 are shown to have a substantially spherical shape; however the solid particles 204 may differ in shape and size from one particle to another. The solid particles may be micron sized (i.e. solid particles in the form of microparticles spanning between 0.1 and 100 pm in size) or smaller. However, in the present embodiment, the solid particles 204 are nanoparticles in that one or more of the solid particles 204 have a maximum span (or diameter) 205 under 100 nanometers, as can be detected and verified using electron microscopy techniques. The use of nanoparticles, or for example any solid particle which is smaller than the diameter of individual fibres 202, 203 in the fabric 201 , may enable the solid particles 204 to more easily locate themselves between individual fibres 202, 203. Further, in the form of nanoparticles, the solid particles 204 may be more easily dispersed uniformly throughout the fabric 201 and between the fibres 202, 203. Nanoparticles may also have reduced mobility as compared to micron sized particles, owing to their smaller size. Some or all of the solid particles 204 may be ceramic materials such as Silica, Alumina, and Titania, which are hard, heat-resistant and corrosion-resistant materials. In the present embodiment, the solid particles 204 comprise Silica (SiC>2) particles only. However, it will be appreciated that in embodiments the solid particles 204 may be any combination of one or more types of ceramic particles.

[0056] Further, the invention is not limited to ceramic particles and the presence of solid particles of any material or type would improve the puncture-resistance of the fabric. For example, the Applicant has found that any solid particle having a hardness of 6 or above on the Mohs hardness scale may significantly increase puncture-resistance of the fabric.

[0057] Further examples of solid particles which are particularly suitable and advantageous for use in the present invention include:

[0058] The solid particles 204 are small (micron sized or smaller) and lightweight (e.g. bulk densities of 10 g / cm3or less) enough to be particularly suitable being retained within the fabric 201. The solid particles 204 are distributed throughout the fabric 201 such that at least some of the solid particles occupy positions that are located between adjacent fibres 202, 203 of the fabric 201. All or part of a given solid particle 204 may occupy a position in the interstitial space between adjacent fibres 202, 203. In that regard, the term “interstitial space” refers generally to any intervening space, gap, opening, cranny etc. between fibres 202, 203. With reference to the woven fabric 201 of Figure 2, the interstitial spaces may be between: adjacent fibres of the first set of fibres 202; adjacent fibres of the second set of fibres 203; and / or a fibre of the first set of fires 202 and a fibre of the second set of fibres 203. By providing solid particles 204 between the fabric fibres 202, 203, the solid particles 204 in effect form obstructions that hinder relative movement of the fibres 202, 203, thereby increasing inter-fibre friction. Further, solid particles 204 will in effect increase the surface roughness of the fibres 202, 203 to which they are attached. Accordingly, if an object such as a needle engages the treated fabric 201 and applies a force on the fibres 202, 203, those fibres 202, 203 will tend to snag on the solid particles 204 exposed in the interstitial spaces. The inter-fibre friction increases the force needed to sufficiently spread the fibres 202, 203 to allow the sharp object to pass therebetween and penetrate the fabric.

[0059] In this way, the protective material of the present invention has increased puncture resistance. This enhances the performance of many fabric-based protective materials such as Kevlar. Further, in an initial study, the protective material of the present invention out-performs epoxy platelet material with respect to needle puncture-resistance. Further, good puncture resistance can be provided by only a single layer of the treated fabric of the present invention. This is advantageous in that protective articles can be made using less quantities of protective materials, leading to weight and cost savings not to mention improved dexterity for embodiments where the protective article is a glove.

[0060] Figure 3 is a bar graph which illustrates the force required for a 21 gauge (21G) needle travelling at a constant velocity of 200 mm. min-1to penetrate two examples of a treated fabric in accordance with the present invention. The graph also illustrates the force required for an identical 21 G needle travelling at a constant velocity of 200 mm. min-1to penetrate the same, yet untreated, fabrics. In this example the fabrics are COTS Kevlar Correctional (KC) and Kevlar Felt (KF) fabrics. The force measurements were made using a COTS tensile tester machine. A first bar 301 of the graph represents the force required for the needle to penetrate the woven KC fabric which has been treated with Silica nanoparticles. A second bar 302 illustrates the force required for an identical needle (travelling at the same speed) to penetrate KC fabric, except that in this case the KC fabric has not been treated with Silica nanoparticles and may be regarded as being in its “raw” form. As can be seen, the needle force required to penetrate the raw KC fabric is less than 3 Newtons, whereas the needle force required to penetrate the treated KC fabric is 11 Newtons. That is, the puncture resistance of the treated KC fabric is over three-and-a-half times greater than that of the raw KC fabric. similar result was obtained for the second example of treated fabric. As can be seen, the graph has a third bar 303 which illustrates the force required for a needle to penetrate a KF fabric which has been treated with Silica nanoparticles. A fourth bar 304 illustrates the force required for an identical needle (travelling at the same speed) to penetrate the same KF fabric, except that in this case the KF fabric has not been treated with Silica nanoparticles and may be regarded as being in its “raw” form. As can be seen, the needle force required to penetrate the raw KF fabric is less than 1 Newtons, whereas the needle force required to penetrate the treated KF fabric is over 11 Newtons. That is, the puncture resistance of the treated KF fabric is over eleven times greater than that of the raw KF fabric. Further, it can be see that the Kevlar felt, i.e. non-woven, fabric provides increased puncture resistance as compared to the KC woven fabric version.

[0061] It will be appreciated that the particular combination of fabric and solid particles described with respect to Figure 3 (i.e. Kevlar fabric and Silica particles) is an example of one particularly advantageous implementation of the present invention. In addition to the example given with respect to Figure 3, the Applicant has found the following combinations of fabric and solid particle types to be particularly effective and resistant to needle puncture: • Colloidal Silica (Ludox ®) with any one of: Kevlar Felt (20N); Acrylic Felt

[0062] (14N); Woven Nylon (e.g. Cordura®) (11 N); and LIHMWPE (Spectra ®) (11 N).

[0063] • Zirconia with any one of: Kevlar Felt (over 32N); and Acrylic Felt (10N).

[0064] • Tin (IV) Oxide with Kevlar Felt (@ 32N needle penetration force); or

[0065] • Titanium Dioxide with Kevlar Felt (providing ~31 N). The last three fabric-particle combinations, i.e. Kevlar Felt with Zirconia, Tin(IV) Oxide or Titanium Dioxide, are particularly advantageous in that over 30 Newtons of force is required for a 21G needle (travelling at a speed of 200 mm. min-1) to penetrate the treated fabric.

[0066] While the solid particles are sufficiently retained to the fabric to increase the puncture resistance of the fabric, the Applicant has recognised that some of the particles may become mobile when the fabric is under very high stresses and loads. However it may be possible, in embodiments, to increase the stability of the solid particles as will now be described. Figure 4 is a diagram which schematically illustrates one such embodiment of a protective material of the present invention. Specifically, Figure 4 shows a top view and a cross-sectional view of a protective material 401.

[0067] As can be seen, the protective material 401 is substantially the same as that described above with respect to Figure 2, in that it comprises a woven fabric 201 which has been treated with solid particles 204. However, in this embodiment the protective material 401 differs from that of Figure 2 in that the treated fabric is entirely encapsulated within a polymer matrix 402. The polymer matrix 402 may comprise any type of polymer, and the selection of the polymer may depend on the application of the protective material, e.g. the type of protective article which is to be formed using the protective material. However, in embodiments the polymer matrix comprises Silicone, e.g. a Silicone rubber, or latex. This may be advantageous where the material is used to form a safety glove. It will however be appreciated that other matrix materials are possible, such as:

[0068] • Polyurethane

[0069] • Latex

[0070] • Natural rubber • Silicone

[0071] • Chlorosulfonated polyethylene synthetic rubber (CSM)

[0072] • Polyethylene glycol

[0073] • Crosslinked polyvinyl alcohol (PVA) By encapsulating the treated fabric within a polymer matrix 402, it is possible to reduce the mobility of the solid particles. This may be advantageous to stabilise the solid particles in the treated fabric, thereby ensuring that the puncture resistance remains consistent across the fabric surface area. Encapsulation may also prevent solid particles from escaping the treated fabric material, thereby increasing the durability and lifetime of the protective material 401. The polymer matrix 402 also shields the treated fabric from the external environment, further increasing durability of the protective material 401. It will be appreciated here that, although the invention has been described above with respect to encapsulating the entire treated fabric within a polymer matrix, in embodiments only some of the treated fabric may be encapsulated within the polymer matrix. In further embodiments, one or more surfaces (or parts thereof) of the treated fibre is coated by the polymer matrix.

[0074] Figure 5 is a flow chart which illustrates one embodiment of a method of preparing the protective material of the present invention, as will now be described.

[0075] The method begins at block 501 of Figure 5, at which a fabric material such as Kevlar or Aramid fabric is provided. The fabric may be any type of fibre-based material known in the art, including woven or non-woven (e.g. felt) materials, and can take any form, such as a sheet, veil, etc. The fabric at this stage may be regarded as being in its “raw” or “untreated” form in that the fibres are not infused or pre-impregnated with a material. Such fabrics are flexible, porous and have good formability.

[0076] The method then proceeds to block 502, at which the raw fabric is treated by infusing the raw fabric with a slurry of solid particles which are suspended in a liquid matrix. The raw fabric may be infused by positioning the fabric in a receptacle which contains the slurry (e.g. the slurry may be poured over the fabric) such that the fabric is entirely impregnated by the slurry to distribute the solid particles throughout the fabric. In alternative embodiments, the slurry may be applied by spraying the fabric with the slurry before it infuses into the fabric material. Other methods are possible. The solid particle slurry may be prepared by mixing COTS solid particles (provided as a dry powder) in the liquid matrix. This may involve the use of a (e.g. high shear) mixer to ensure adequate dispersion and suspension of the solid particles in the liquid matrix. In alternative embodiments, the solid particle slurry may be obtainable as a COTS product containing specified concentrations of solid particles in the liquid matrix. As described with respect to Figure 2, the solid particles may be nanoparticles and this may facilitate suspension and microscopic dispersion of the solid particles throughout the liquid matrix, thereby increasing the uniformity and consistency of the slurry. In the present embodiment, the slurry comprises only the solid particles and a liquid matrix of water. However, in further embodiments one or more dispersants or rheological modifiers may also be added to the slurry. Further, any liquid matrix which is suitable for suspending the solid particles therein can be used. Indeed, in some embodiments, the liquid matrix will be selected or tailored based on the types of fibres in the fabric. For example, inorganic solvents may be used instead of water in embodiments where the fibres of the fabric are prone to degradation when subjected to water.

[0077] The level of puncture resistance of the treated fabric can be tuned at this stage by tailoring the concentration (e.g. weight or volume percentage) of solid particles in the solid particle slurry, and thus the loading or areal density of the particles in the treated fabric (i.e. the mass of solid particles per unit of area of fabric). This is in contrast to conventional protective materials such as epoxy platelet materials, where the number of layers of protective materials in an article is altered to tune the level of puncture resistance.

[0078] Accordingly, the loading (or areal density) of solid particles in the treated fabric can be set during manufacture by selecting and using a solid particle slurry having a predetermined concentration (weight or volume percentage) of solid particles corresponding to the areal density of solid particles for the treated fabric. In that regard, the method of the present invention may comprise a preliminary step wherein a predetermined concentration of solid particles in the slurry is determined for a given, e.g. desirable, loading (or areal density) of solid particles in the treated fabric. In that regard, it will be appreciated that the lower the areal density of solid particles in the treated fabric, the lesser the puncture resistance but the greater the flexibility and thus dexterity of the fabric. The opposite can be said for higher areal densities of solid particles.

[0079] In the present embodiment, the slurry comprises solid particles in an amount of 50% by total weight of the slurry (with the other 50% being water). This may be advantageous in that it provides an optimum loading of solid particles in the protective material, to increase puncture-resistance while maintaining sufficient flexibility. However, the Applicant has found that improved puncture resistance (compared to untreated fabric) is achieved with the presence of solid particles in any quantity (i.e. any non-zero areal density) such that the invention is not limited to any given example of loading, areal density or slurry concentration described herein.

[0080] In addition to the above, the level of puncture resistance of the treated fabric can be tuned and set at this stage by tailoring the exposure time during which the raw fabric is exposed to the solid particle slurry, and thus the loading or areal density of the particles in the treated fabric. For any solid particle concentration, the longer the fabric is exposed to the solid particle slurry, the greater the loading and thus areal density of solid particles in the fabric.

[0081] After the fabric has been exposed to the slurry for a predefined exposure time, the method proceeds to block 503 at which the infused fabric is removed from the receptacle and the liquid matrix is removed from the slurry and fabric mixture to leave behind the treated fabric. The liquid matrix may be removed by drying or curing the infused fabric for a predetermined time period, during which the liquid matrix is evaporated from the mixture. The treated fabric is a lightweight, flexible and puncture resistant material.

[0082] In an optional further embodiment, all or part of the treated fabric may then be partially or wholly encapsulated within a polymer matrix such as Silicone or Latex.

[0083] Any known method of encapsulating or coating materials with a polymer matrix can be used. For example, the polymer matrix may be applied to the treated fabric by brushing or spraying the polymer matrix on to the treated fabric. In another embodiment, the polymer matrix may be held in a receptacle or reservoir in a liquid or viscous form and all or part of the treated fabric material may be dipped into or submerged by the liquid or viscous polymer matrix so as to encapsulate the material within, or coat surface regions thereof with, the polymer matrix.

[0084] The polymer matrix is then dried or cured, depending on the type of polymer matrix used. For example, where Silicone is used the polymer matrix will be cured in an oven, whereas a latex based polymer matrix can be air dried.

[0085] Having completed the steps described above with respect to blocks 501 to 503, and optionally the step of encapsulating the treated fabric, the protective material can be used, wholly or in part (i.e. together with other materials), to form a protective article, such as a safety glove. The applications for the protective material are wide and varied, such that the invention should not be limited to any specific article or method of forming the protective article using the protective material. However, forming the protective article may include a step of manipulating (e.g. shaping) the protective material, e.g. using one or more moulds, into the form (desired shape) of the final article. Additionally or alternatively, the final article may be formed by attaching separate protective materials of the present invention together. In embodiments where the treated fabric is to be encapsulated by a polymer matrix, a method of providing a protective article may itself include the steps of forming the protective material as described above with respect to Figure 5. Further, the raw fabric may be manipulated (e.g. shaped, sown etc.) into the form (e.g. shape) of the final article, e.g. a glove, before the step of treating the fabric with the solid particle slurry (and subsequent encapsulation by a polymer matrix).

[0086] Alternatively, the raw fabric may be treated first and then manipulated into the form of the final article before the step of encapsulating the treated fabric within a polymer matrix. In that regard, the treatment steps at blocks 502 and 503 of the method in Figure 5 may be performed in a rol l-to-roll processing method, whereby a roll of raw fabric sheet is unrolled from its reel and treated before it is then re-reeled to create an output roll of treated fabric which may be used as desired to form protective articles. This may enable fast and easy manufacture of a treated fabric at scale. Indeed, the method of the present invention described with respect to blocks 501- 503 of Figure 5 is particularly suitable for use with existing roll-to-roll processing equipment that are conventionally used in the paper processing industry.

[0087] The methods described above significantly improve the fabric’s resistance to needle puncture. However, the Applicant has found that the liquid matrix (e.g. water) in the slurry may bead along the surface of the fabric. These beads scattered across the surface can cause particles to be located in separate regions where the beading occurs. This can leave small gaps of untreated fabric (where no particles are present) that are vulnerable to puncture. To address this, in embodiments the present invention may use wettable fabrics and / or may pre-treat the raw fabric (wettable or otherwise) with a hydrophilic material prior to infusing the fabric with the slurry of solid particles.

[0088] One example of a wettable fabric that is suitable for use in the present invention is ultra-high moleculite polyethylene or LIHMWPE. However, any wettable fabric which is highly effective at dispersing moisture through the fabric is suitable for use in the present invention. Such fabrics may be identified using conventional techniques for measuring wettability of a material. For example, the so-called “contact angle” can be used to define whether a surface is wettable, and this can be measured using conventional techniques known in the art. The contact angle is a measure of the tendency of a liquid drop to spread out over a flat, solid surface, i.e. the angle at which the liquid-gas interface meets the solid-liquid interface. As the tendency of a drop to spread out increases, the contact angle decreases. Thus, the contact angle provides an inverse measure of wettability. The present invention may use wettable fabrics where the contact angle is less than 90 degrees, preferably less than 45 degrees. A contact angle less than 90° (low contact angle) usually indicates that wetting of the surface is very favorable, and the fluid will spread over a large area of the surface. Using a wettable fabric may increase the extent by which, and the uniformity with which, the slurry and thus solid particles spreads across and throughout the fabric. This may reduce the number of gaps of untreated fabric (i.e. where no particles are present) that are vulnerable to puncture. With better coverage of solid particles, the present invention may increase the resistance of the treated fabric to needle puncture. That is, it may increase the force required for a needle to puncture the treated fabric. Further, the use of a wettable fabric may increase adhesion of the solid particles to the fabric, as they are able to occupy more spaces between fibres. As stated above, the fabric may be pre-treated with a hydrophilic material in a step prior to infusing the fabric with the slurry of solid particles. For example, the fibres may be coated with a hydrophilic material. By imparting on the fabric hydrophilic properties, the liquid matrix forms a film across the fabric and its fibres, and that full film coverage enables the solid particles to spread through the film evenly and in turn dry with increased and uniform coverage throughout the fabric. It may also improve the extent of adhesion of particles to the fabric.

[0089] The hydrophobic coating can be made from many different hydrophilic materials.

[0090] The following are hydrophilic materials that are known in the art: ■ Polyvinylpyrolidone (PVP)

[0091] ■ Polyurethanes

[0092] ■ Polyacrylic acid (PAA)

[0093] ■ Polyethylene oxide (PEO)

[0094] ■ Polysaccharide materials ■ Hydrogels

[0095] The hydrophobic coating may be applied to the fabric using techniques known in the art. For example, a liquid solution containing a hydrophilic material (and, e.g., a solvent) may be applied to the fabric by dipping, flow coating or spraying before it is dried or cured by heating and / or application of ultraviolet light.

[0096] It will be appreciated that by increasing the extent and uniformity with which the solid particles are dispersed throughout the treated fabric (when dried), the present invention provides a protective material that is especially suitable for and effective against needle punctures, or very sharp / thin objects generally. This is in contrast to hypothetical materials which seek to protect against forces acting across a bulk part of the material, e.g. due to impact of blunt objects. Indeed, such materials are not concerned with how to provide a material that protects against sharp objects such as needles or glass shards. It will also be appreciated that while the invention has been described above with respect to applying or infusing a slurry of solid particles to the fabric, this is not required. It may be possible to incorporate the solid particles into the fabric in other ways. For example, the powder may be impregnated into the fabric during a felting process.

[0097] Embodiments of the present disclosure have been described above with reference to the accompanying drawings, in which some, but not all embodiments are shown. It will be appreciated that whilst various aspects and embodiments of the present invention have heretofore been described, the scope of the present invention is not limited to the embodiments set out herein and instead extends to encompass all methods and arrangements, and modifications and alterations thereto, which fall within the scope of the appended claims.

Claims

Claims1 . A protective material comprising a treated fabric, wherein the treated fabric has solid particles dispersed between its fibres to increase inter-fibre friction.

2. The protective material of claim 1 , wherein the fabric is a Kevlar fabric or an Aramid fabric.

3. The protective material of any preceding claim, wherein the fabric is a nonwoven felt material.

4. The protective material of any preceding claim, comprising solid particles in an amount of at least 10%, at least 15%, at least 20%, at least 25% at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70% or at least 75% by total volume or by total weight of the treated fabric.

5. The protective material of any preceding claim, wherein the fabric is a Kevlar Felt and the solid particles are selected from one of: Zirconia, Tin(IV) Oxide and Titanium Dioxide.

6. The protective material of any preceding claim, wherein the treated fabric is at least partly encapsulated within a polymer matrix.

7. The protective material of claim 6, wherein the polymer matrix comprises Silicone.

8. A protective article comprising the protective material of any preceding claim.

9. A method for preparing a protective material, the method comprising: providing a fabric; and forming a treated fabric by: infusing the fabric with a slurry of solid particles suspended in a liquid matrix; andremoving the liquid matrix to leave the solid particles dispersed between the fibres of the fabric.

10. The method for preparing a protective material of claim 9, wherein the slurry comprises solid particles in an amount of at least 30% by total volume or by total weight of the slurry.

11. The method for preparing a protective material of claim 9 or 10, wherein the slurry comprises solid particles in an amount of approximately 50% by total volume or by total weight of the slurry.

12. The method for preparing a protective material of claim 9, 10 or 11 , wherein the liquid matrix is water.

13. The method for preparing a protective material of any one of claims 9 to12, wherein the slurry has been selected or pre-prepared to have a specific concentration of solid particles which has been predetermined to correspond to a predefined loading or areal density of solid particles in the treated fabric.

14. The method for preparing a protective material of any one of claims 9 to13, wherein the liquid matrix is removed by drying or curing.

15. The method for preparing a protective material of any one of claims 9 to14, further comprising a step of encapsulating the treated fabric within a polymer matrix.

16. A method of preparing a protective article, comprising: providing a protective material as claimed in claim 6 or 7, or preparing a protective material according to the method of claim 15; and manipulating the protective material into the form of the final protective article.

17. A method of preparing a protective article, comprising;providing a protective material as claimed in any one of claims 1-5 or preparing a protective material in a manner as claimed in any one of claims 9-14; and manipulating the protective material into the form of the final protective article.

18. The method for preparing a protective article as claimed in claim 17, further comprising encapsulating all or part of the protective material within a polymer matrix after the step of manipulating the protective material into the form of the final protective article.

19. A method for preparing a protective article, comprising in turn the steps of: providing a raw fabric material; manipulating the raw fabric material into the form of the protective article; infusing the raw fabric material with a slurry of solid particles suspended in a liquid matrix; and removing the liquid matrix to leave behind a treated fabric having solid particles dispersed between its fibres.

20. A method for preparing a protective article as claimed in claim 19, further comprising encapsulating all or part of the treated fabric within a polymer matrix.

21. The method for preparing a protective material of claim 9, wherein the fabric is a wettable fabric.

22. The method for preparing a protective material of claim 9, wherein fibres of the fabric are coated by a hydrophilic material prior to infusing the fabric with the slurry of solid particles.

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