GB2609041A

GB2609041A - Water absorbing and antimicrobial fabric composition

Info

Publication number: GB2609041A
Application number: GB2110429.4A
Authority: GB
Inventors: Arron Whale Eric; Gwyddon Hepworth David; Moir Malcolm; Campbell James
Original assignee: Halley Stevensons Dyers & Finishers Ltd; Cellucomp Ltd
Current assignee: Halley Stevensons Dyers & Finishers Ltd; Cellucomp Ltd
Priority date: 2021-07-20
Filing date: 2021-07-20
Publication date: 2023-01-25
Also published as: GB202110429D0; WO2023001909A1

Abstract

An antimicrobial fabric comprising: a first fabric layer; an adhesive layer comprising adhesive material and functionalised cellulose active material particles; and a second fabric layer. The adhesive layer is adhered to the first fabric layer and to the second fabric layer. The antimicrobial fabric is manufactured by heating the three layers under pressure to adhere the layers together. The first and second fabric layers may comprise a non-woven or woven layer, and is preferably water repellent but at least in part gas transmissive. The cellulose is preferably functionalised with antimicrobially active nanoparticles such as silver nanoparticles (AgNPs). In another embodiment, the cellulose is functionalised with antimicrobial peptides and/or proteins. Preferably the antimicrobial fabric is used in personal protective equipment (PPE), particularly face masks, although it may be used in clothing or other garments.

Description

Water absorbing and antimicrobial fabric composition This invention relates to fabric compositions possessing good moisture absorbing and antimicrobial properties, comprising functionalised cellulose active material, as well as their method of manufacture. The invention further relates to antimicrobial and water wicking articles of clothing comprising said fabric compositions, in particular sportswear and personal protective equipment, such as face masks.

Background to the Invention

Fabrics have been provided from ancient times and continue to be an integral part of civilised life. Fabrics have and assortment of uses, from uses in clothing and containers, such as bags, through coverings for tables and beds. Functional fabrics are fabrics that are not selected for their mere aesthetic appearance, but also perform a technical function. Examples of technical fabrics include medical textiles, protective textiles and sports textiles. Functional fabrics in a medical context include sterile wound dressings, face masks and surgical masks, bedding and patient clothing. Here the fabric may be functionalised to possess antimicrobial properties or to be resistant to washing at high temperatures used to sterilise articles. Functional fabrics in in a protection context include personal protective clothing, such as N95 respirators, where the fabric serves to inhibit inhalation of small, harmful particulates. Functional fabrics in a sports context include sports textiles with water wicking functions and running shoes with antimicrobial activity to inhibit the growth of odour generating bacteria.

An outstanding challenge in the domain of functional fabrics is the economic provision of a fabric that is breathable, moisture wicking and possesses antimicrobial activity (antibacterial, antiviral and/or antifungal activity).

There have been extensive attempts to render fabrics antimicrobial by the inclusion of antimicrobial particles of micrometre or nanometre size. The loss of these antimicrobial functional particles on washing fabric is a major obstacle to their economic use, as single use fabrics comprise a small segment of the total fabric market and rapid loss of antimicrobial function on washing severely limits the lifespan of re-useable antimicrobial functional fabrics. There are also regimes where there are strict rules for nanoparticles entering the waste stream (i.e. dirty water from washing machines). It therefore remains a challenge to provide functional fabrics which do not lose their antimicrobial functional particles on washing.

Personal protective equipment (PPE) comprises protective clothing and other equipment designed to protect the wearers body from injury or infection. Within the medical sector, PPE is typically worn to protect against biohazards, such a bacteria or viruses. In a medical setting typical PPE equipment comprises face masks, surgical masks, respirators and PPE gowns.

Face masks have generally been designed to greatly reduce, if not prevent, the transmission of liquids and/or airborne contaminates through the face mask. In surgical procedure environments, such liquid sources include a patient's perspiration, blood and life support liquids such as plasma and saline. Examples of airborne contaminates include biological contaminants, such as bacteria, viruses and fungal spores. Such contaminates may also include particulates such as, mineral fines, dust, skin squames and respiratory droplets. A measure of a fabrics ability to prevent the passage of such airborne materials is typically expressed in terms of "filtration efficiency".

Early face masks were made of simple cotton or linen fabric. However, these early masks permitted transmission or "strike-through" of various liquids encountered in surgical procedures.

In these instances, a path was established for transmission of biological contaminates, either present in the liquid or subsequently contacting the liquid, through the face mask. Additionally, in many instances face masks fashioned from simple cotton or linen fabric provide insufficient barrier protection from the transmission of airborne contaminates, such as micrometre sized droplets containing viruses, which can easily pass through simple cotton fabrics. Furthermore, these articles are typically deemed too expensive for disposable use, and hence require laundering and sterilization procedures for reuse.

Disposable face masks have largely replaced linen face masks in a medical setting. Recent developments (such as the 2021-2022 COVID pandemic) have led to widespread use of disposable face masks by the general public. Day-to-day use of disposable facemasks (such as when shopping, commuting or working in an office space) by large numbers of people has led to an phenomenal increase in use, and hence disposal, outside of medical centres of face masks. This presents a significant environmental problem, as face masks are routinely disposed of by littering. As the majority of disposable face masks comprise no-biodegradable plastics, this leads to significant and long-lasting environmental problems, such as microplastic pollution of waterways and oceans. An outstanding challenge is therefore the provision of reusable facemask that do not enter the waste-stream or biodegradable face masks that will help mitigate the environmental impact of disposed face masks. Advances in such disposable face masks include the formation of such articles from totally liquid repellent fabrics and/or apertured films which prevent liquid strike-through. In this way, biological contaminates carried by liquids are prevented from passing through such fabrics.

However, in some instances, face masks formed from apertured films, while being impervious to liquid and airborne contaminants become uncomfortable to wear over an extended period of time due to their water impermeable nature, with sweat accumulation causing discomfort. Furthermore, such face masks are relatively more costly than face masks containing only nonwoven webs.

In some instances, face masks fashioned from liquid repellent fabrics, such as fabrics formed from nonwoven polymers, sufficiently repel liquids and are more breathable and thus more comfortable to the wearer than nonporous materials. However, these improvements in comfort and breathability provided by such nonwoven fabrics have typically occurred at the expense of barrier properties or filtration efficiency.

One type of nonwoven fabric, a conventional spunbonded/meltblown/spunbonded (SMS) laminate, has been widely used in surgical garments, such as gowns and drapes, due to its excellent barrier properties and relatively low cost. To date, such SMS laminates have not been used in commercially available face masks due to their unacceptable breathability properties.

Consequently, the search for face mask materials, which will provide liquid strike-through protection, breathability, and comfort at a relatively low cost, continues.

Therefore, there exists a need in the art for fabrics, face masks and methods for making the same, which provide improved liquid strike-through protection, breathability, and comfort, as well as, improved filtration efficiency.

There have been attempts to render face masks antimicrobial by the inclusion of antimicrobial particles of micrometre or nanometre size. A major disadvantage is that if nanoparticles or microparticles come loose during mask use, the end user can inhale said micro or nanoparticles and potentially suffer health issues. Face masks comprising nanoparticulate graphene were withdrawn from sale in Canada for this reason in 2021. Further, the loss of these antimicrobial functional particles on washing face masks is a major obstacle to their economic use as re-usable facemasks. Single-use, disposable face masks comprising nanoparticles suffer a drawback in that there are regimes where there are strict rules for nanoparticles entering the waste stream (i.e. placing nanomaterial comprising articles in landfill). It therefore remains a challenge to provide functional fabrics which do not lose their antimicrobial functional particles on washing.

As such, it remains a challenge to provide face masks that contain antimicrobial functional particles that do not become detached from the face mask during use or during washing, whilst also retaining sufficient breathability, comfort, and improved filtration efficiency. Brief Summary of the invention In accordance with the present inventions there is provided fabric compositions possessing good moisture absorbing and antimicrobial properties, comprising functionalised cellulose active material, as well as their method of manufacture. The invention further relates to antimicrobial and water wicking articles of clothing comprising said fabric compositions, in particular sportswear and personal protective equipment, such as face masks.

Brief Description of the drawings

Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a picture taken during optical microscopy of the matrix of functionalised cellulose active material particles and adhesive between two cotton fabric layers.

Figure 2 is a UV-VIS spectrum of the supernatant used to wash silver nanoparticle functionalised cellulose active material particles according to the invention at 70 °C for 120 minutes, of wash cycles 1(29-3 CurranAgW1), wash cycle 2(29-3 CurranAgW2) and wash cycle 4 (29-3 CurranAgW4).

Figure 3 is a cartoon explaining what films were placed on existing biofilm on a plate, where a bacterial lawn solution was subsequently applied (see Figures 4 and 5) Figure 4 are images showing experimental results of GFP-expressing Escherichia coli EC5025 bacteria after 24 h contact with the composition according to the invention compared to controls. All the plates are deposited in an identical pattern as depicted for 4A (as also explained by the cartoon of Figure 3) and are orientated in the same direction.

Figure 5 are images showing experimental results of GFP-expressing Pseudomonas syringae KP71 bacteria after 24 h contact with the composition according to the invention compared to controls. All the plates are deposited in an identical pattern as depicted for 5A (as also explained by the cartoon of Figure 3) and are orientated in the same direction.

Detailed Description

The following standard methods for determining parameters are used throughout the patent.

Air permeability values are obtained according to ISO 9237 (1995).

Splash resistance is determined according to EN 14683:2019+AC:2019.

Filtration efficiency is measured by the method of international standard EN 14683:2019+AC:2019.

The antiviral properties of textiles can be determined by ISO 18184:2019 "Determination of antiviral activity of textile products".

Antibacterial as defined by ISO 20743 (2021).

Antifungal as defined by ISO 13629 (2014).

Biodegradable is defined by EN 13432 (2000) standard "Requirements for packaging recoverable through composting and biodegradation -test scheme and evaluation criteria for the final acceptance of packaging".

The following definitions will be used in the patent: Nanoparticle: a particle of matter that is between 1-250 nm in diameter as determined by dynamic light scattering.

Antimicrobial: defined as having an adverse effect on a range of pathogenic microorganisms, including bacteria and at least some fungi and viruses An antimicrobial adsorbent is generally preferred over an antibacterial adsorbent.

As used herein, the term "bound" refers to a material physiosorbed (physically absorbed) or chemisorbed (chemically bound) to another material.

As used herein, the term "metallised" refers to the materials wherein metal nanoparticles have been formed.

Attachment: the stable colocalization of peptides or proteins with cellulose particulate material after several washing steps with water at room temperature.

A first aspect of the invention concerns a fabric comprising: a first fabric layer; an adhesive layer comprising adhesive material and functionalised cellulose active material; and a second fabric layer, Wherein the adhesive layer is adhered to the first fabric layer and to the second fabric layer.

The first fabric layer may be woven fabric or non-woven fabric.

As used herein, the term "woven fabric" refers to any textile formed from fibres by weaving. Woven fabrics are often created on a loom, and made of many threads woven on a warp and a weft. Woven fabrics can be made of both natural and synthetic fibres, and are often made from a mixture of both. E.g. 100% Cotton or 80% Cotton & 20% polyester.

Preferable woven fabrics are selected from buckram fabric, cambric fabric, casement fabric, cheese cloth, chiffon fabric, chintz fabric, corduroy fabric, crepe fabric, denim fabric, drill fabric, flannel fabric, garbadine fabric, georgette fabric, Kashmir silk fabric, Khadi fabric, lawn fabric, mulmul fabric, muslin fabric, poplin fabric, sheeting fabric, taffeta fabric, tissue fabric, aertex fabric, Madras muslin net fabric, Aida cloth fabric, velvet fabric, mousseline fabric, organdie fabric, organza fabric or leno fabric.

As used herein, the term "non-woven fabric" refers to a fabric that has a structure of individual fibres or filaments which are randomly and/or unidirectionally interlaid in a mat-like fashion. Non-woven fabrics can be made from a variety of processes including, but not limited to, air-laid processes, wet-laid processes, hydroentangling processes, staple fibre carding and bonding and solution spinning. Some suitable non-woven fabrics include, but are not limited to, spunbonded fabrics, melt-blown fabrics, wet-laid fabrics and combinations thereof.

As used herein, the term "spunbonded fabric" refers to a web of small diameter fibres and/or filaments which are formed by extruding a molten thermoplastic material, or coextruding more than one molten thermoplastic material, as filaments from a plurality of fine, usually circular, capillaries in a spinnerette with the diameter of the extruded filaments then being rapidly reduced, for example, by non-eductive or eductive fluid-drawing or other well-known spunbonding mechanisms. The production of spunbonded nonwoven webs is illustrated in patents such as Appel, et al., U.S. Pat. No. 4,340,563; Dorschner et al., U.S. Pat. No. 3,692,618; Kinney, U.S. Pat. Nos. 3,338,992 and 3,341,394; Levy, U.S. Pat. No. 3,276,944; Peterson, U.S. Pat. No. 3,502,538; Hartman, U.S. Pat. No. 3,502,763; Dobo et al., U.S. Pat. No. 3,542,615; and Harmon, Canadian Patent No. 803,714.

As used herein, the term "melt-blown fabrics" refers to a fabric comprising fibres formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into a high velocity gas stream (such as air) that attenuates the filaments of molten thermoplastic material so as to reduce their diameters, which may be to microfiber diameter. Thereafter, the melt-blown fibres are carried by the high-velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed melt-blown fibres. The melt-blown process is well-known and is described in various patents and publications such as US 3849241.

As used herein, the term "microfibers" means small diameter fibres having an average diameter not greater than about 100 p.m, for example, having a diameter of from about 0.5 p.m to about 50 pm. More specifically microfibers may also have an average diameter of from about 1 pm to about 20 pm. Microfibers having an average diameter of about 3 pm or less are commonly referred to as ultra-fine microfibers.

As used herein, the term "wet-laid fabrics" refers to fabrics formed by a process, such as a paper-manufacturing process, wherein fibres are dispersed in a liquid medium, then deposited onto a screen so that the liquid medium flows through the screen, leaving a resultant fabric on the surface of the screen. Fibber bonding agents may be applied to the fibres in the liquid medium or after deposition onto the screen. Wet-laid fabrics may contain natural and/or synthetic fibres. As used herein, the term "spunlaced fabrics" refers to a web of material consisting of a blend of synthetic and natural fibres, where the fibres are subjected to high-velocity water jets that entangle the fibres to achieve mechanical bonding. Desirably, the natural fibres are wood pulp fibres and the synthetic fibres are polyester fibres.

Mono-component and conjugate synthetic fibres suitable for the present invention can be produced from a wide variety of thermoplastic polymers that are known to form fibres. Suitable polymers for use in the present invention include, but are not limited to, polyolefins, e.g., polyethylene, polypropylene, polybutylene, and the like; polyamides, e.g., nylon 6, nylon 6/6, nylon 10, nylon 12 and the like; polyesters, e.g., polyethylene terephthalate, polybutylene terephthalate and the like; polycarbonates; polystyrenes; thermoplastic elastomers, e.g., ethylenepropylene rubbers, styrenic block copolymers, copolyester elastomers and polyamide elastomers and the like; fluoropolymers, e.g., polytetrafluoroethylene and polytrifluorochloroethylene; vinyl polymers, e.g., polyvinyl chloride, polyurethanes; and blends and copolymers thereof. Particularly suitable polymers for use in of the present invention are polyolefins, including polyethylene; polypropylene; polybutylene; and copolymers as well as blends thereof. Of the suitable polymers for forming conjugate fibres, particularly suitable polymers for the high melting component of the conjugate fibres include polypropylene, copolymers of polypropylene and ethylene and blends thereof, more particularly polypropylene, and particularly suitable polymers for the low melting component include polyethylenes, more particularly linear low density polyethylene, high density polyethylene and blends thereof; and most particularly suitable component polymers for conjugate fibres are polyethylene and polypropylene.

Suitable fibre forming polymers may additionally have thermoplastic elastomers blended therein. In addition, the polymer components may contain additives for enhancing the crimpability and/or lowering the bonding temperature of the fibres, and enhancing the abrasion resistance, strength and softness of the resulting webs. For example, the low melting polymer component may contain about 5 to about 20% by weight of a thermoplastic elastomer such as an ABA' block copolymer of styrene, ethylenebutylene and styrene. Such copolymers are commercially available.

Some are disclosed in U.S. 4663220. An example of highly suitable elastomeric block copolymers is KRATON G-2740. Another group of suitable additive polymers is ethylene alkyl acrylate copolymers, such as ethylene butyl acetate, ethylene methyl acrylate and ethylene ethyl acrylate, and the suitable amount to produce the desired properties is from about 2 wt. % to about 50 wt. %, based on the total weight of the low melting polymer component. Yet other suitable additive polymers include polybutylene copolymers and ethylene-propylene copolymers.

Natural fibres suitable for the present invention include abaca (also known as Manila hemp), cotton, coir (coconut husk derived fibres), hemp, linen, ramie fibre, sisal, jute, kapok, ramina (china grass), alpaca wool, angora (rabbit) wool, cashmere (goat) wool, sheep wool, mohair (goat) wool, camel hair or silk.

The adhesive layer comprises adhesive particles and functionalised cellulose active material particles.

The adhesive is selected from any suitable fabric adhesive. Preferably, the adhesive is selected from a thermoplastic polymer. The adhesive may suitably be provided as a powder. The adhesive may suitably be provided as a thermoplastic web and or mesh of fibres that melt under the application of heat and/or pressure.

As used herein "Thermoplastic" refers to polymers that reversibly soften or melt and become pliable or flowable when heated to a temperature above a softening temperature characteristic of the material, and that will re-solidify upon cooling to a temperature that is below the softening temperature. Preferred thermoplastic polymers may be heated to reversibly soften or melt, then cooled and re-solidified, repeatedly, without substantial degradation of the polymer.

The term "thermoplastic" does not encompass polymers that are thermoset.

"Thermoplastic adhesive" as used herein refers to adhesive based on thermoplastic. "Thermoset adhesive" as used herein refers to polymers that form permanent, heat-resistant, insoluble bonds that cannot be reversibly modified using heat, without degradation.

Exemplary thermoplastic adhesives include nitrocellulose, polyvinyl acetate, vinyl acetate-ethylene copolymer, polyethylene, polypropylene, polyamides, polyesters, acrylics, cyanoacrylics, polyurethanes, variety of block copolymers and elastomers such as butyl rubber, ethylene-propylene copolymer, and styrene-butadiene rubber. Other thermoplastic based adhesive include adhesives referred herein as hot-melt or hotfix, such as for instance high melting waxes.

The functionalised cellulose active material particles are made from processed plant material.

Plant Material: The starting material for the materials according to the present invention comprises herbaceous plant material. The term "herbaceous" as defined herein refers to plants which are annual, biennial or perennial vascular plants. In annual, biennial or perennial vascular plants, the stem matter dies after each season of growth when the plant becomes dormant, i.e. biennial or perennial plants, or dies, i.e. annual plants. Biennial or perennial plants survive unfavorable conditions underground and will regrow in more favorable conditions from such underground portions of the plant, typically stem, roots, or storage organs such as tubers. In contrast, the stems of woody species remain during any period of dormancy, and in a period of further growth will form growth rings which expand the girth of existing tissue. Herbaceous plants are characterized by parenchymal tissue having an abundance of primary cell walls within the tissue. One skilled in the art would also be aware that the mosses and macro algae also consist of an abundance of primary cell walls, and hence are included within the term "herbaceous plant material" as used herein. Herbaceous plant material is preferably used as a starting material within the present invention. Optionally, the starting material of the present invention substantially consists of herbaceous plant material. It can be advantageous for the starting material of the present invention to consist of herbaceous plant material, and thereby exclude wood or wood products. Depending upon the intended end use of the cellulose-containing material, however, it may not, however, be necessary to totally avoid inclusion of non-herbaceous plant material such as wood within the plant starting material.

In particular, the plant material used to prepare the cellulose active material particles of the present invention can conveniently include vegetables, for example root vegetables, and fruit. Non-limiting examples of suitable root vegetables include carrot, sugar beet, also commonly referenced as "beet", turnip, parsnip and swede. Exemplary fruit materials which can be used within the present invention includes apples, pears, citrus and grapes. Optionally, the plant material may be from tubers, for example potato; sweet potato, yam, rutabaya and yucca root can also be used.

Generally, it is anticipated that the cellulose active material particles of the invention will be made from waste or coproducts from the plant material after a main product has been extracted, for example sugar beet pellets, vegetable peelings or citrus waste after juicing, jam-making or the like. However this is not strictly necessary, and the process could be operated using vegetable or fruit grown specifically for that purpose. It is also not necessary for the plant material to be used as a starting material in the process of the present invention to comprise material from only one specific plant source.

Optionally, a mixture of materials from different plant sources can be used. For example, the starting material can comprise a mixture of different root vegetables, a mixture of different fruits, a combination of fruit and vegetable(s), including a mixture of root vegetables together with a mixture of fruits.

Generally, the plant material to be used as a starting material for the cellulose active material particles of the present invention will not comprise a significant quantity of lignin. Optionally, the starting material for the cellulose active material particles of the present invention will comprise less than about 20 wt.% lignin, for example less than about 10 wt.% lignin, for example less than about 5 wt.% lignin, for example less than 2 wt.% lignin, for example less than about 1 wt.% lignin. A number of methods for the measurement of lignin content are known in the art and include methods such as the "Klason method", the acetyl bromide method and the thioglycolic acid method. Hatfield and Fukushima (Crop Sci. 45:832-839, 2005) discuss methods of lignin measurement.

The plant material preferably comprises chemically untreated raw plant material, i.e. uncooked. Alternatively, it may have been subjected to an extraction step to remove water soluble compounds.

A particularly preferred plant material comprises sugar beet (beta vulgaris) materials obtained after the sugar juice extraction step. Other suitable materials may be passed through a similar process, e.g. orange peels or apple residue obtained from pressing of juice. Ideally, in this process, the raw plant materials are washed to remove any non-plant material debris or contaminants and leaves. Then typically juice is obtained from those plant materials, by washing and cut up into chips having a thickness in the range of from 0.2 to 0.5 cm. In case of sugar beets, sugar is extracted from these chips typically by contacting the chips with hot extraction water, usually in a counter-current direction in an extraction tower. The crude extract is then usually filtered off, and further worked up. The remaining chips were found to form a particularly good starting material for the present process. In the production of sugar, sugar beets are harvested, washed and processed in sugar beet cutting machines to form chips. The beet chips are subsequently extracted with hot water, at a temperature ranging of from 65°C to 75° C, generally in a counter-current flow direction, and primarily using a diffusion process, and eventually a physical separation, such as pressing and/or centrifugation. This results in extracted sugar beet chips and sugar-containing raw sugar beet juice.

These extracted sugar beet chips primarily comprise of the cell wall and fibre constituents of the extracted sugar beet. In a subsequent processing stage, the beet chips are typically further dewatered by pressing them in so-called pulp presses, which results in pressed chips and released press water, optionally also using pressing aids. These dewatered and pressed chips are then typically subjected to a thermal removal of the residual water. Herein, the pressed chips are dried at an elevated temperature in rotating and heated drying drums, evaporating residual water and constituents volatile at the conditions. Conventional drying systems apply a so-called high-temperature drying, whereas alternative drying methods make use of indirect drying by means of superheated steam using a fluidized-bed method. Sugar-containing molasses are typically added at this stage if the pressed chips are to be employed as animal feed component. The pressed and dried chips are then usually pelletized, by simultaneously pressing the chips to obtain a compressed composition, and by passing the compressed composition through a granulator such as an extruder or hammer mill, wherein the composition is pelletized. The thus obtained pellets are usually added to animal feedstuff, typically those enriched with sugar-containing molasses. The plant material may also be treated prior to, or after comminuting to a smaller particle size. Accordingly, the material may be subjected to a process involving contacting the plant material or obtained with a suitable reagent, such as an alkaline reagent, such caustic soda or lye, and/or water, or an aqueous solution of a peroxide, such as hydrogen peroxide, and/or an oxidative treatment, such as e.g. a hypochlorite. It is not essential for the reagent to be added simultaneously with the water. However, it is often convenient to add the water and reagent simultaneously. For example, it is possible to premix the reagent with the water and then to add the water-reagent mixture to the plant material, or microparticles. Alternatively, it is possible to add water to the particles of plant material to form an aqueous slurry, and then to add the reagent to the slurry. Advantageously, addition of the water and/or reagent is accompanied by stirring of the resultant mixture to facilitate formation of a homogenous composition. The volume of water to be added is not particularly critical, but may typically be from 2 litres to 30 litres water per kg plant material particles. This is in addition to any solution of reagent which may additionally be added. One of the benefits of this is the relatively high percentage of solids which can be present within the mixture after the addition of water and reagent. In some cases, the mixture formed in the first step can contain more than 2 wt.% solids. In some cases, the mixture formed in the first step can contain at least 3 wt.% solids, for example at least 4 wt.% solids, at least 5 wt.% solids, at least 6 wt.% solids, at least 7 wt.%, at least 8 wt.% solids, at least 9 wt.% solids, or at least 10 wt.% solids.

This treatment step is intended to essentially to not break down the particles, but to remove components that may dissolve easily, and hence later may lead to leaching out of the antimicrobial agents. The process may then be followed by a filtration and washing step to remove unused reagent and soluble components, and drying step.

The cellulosic product, whether washed, treated and washed or directly obtained from a process to remove juices or other desired components is then subjected to a comminution step, e.g. by milling the materials, to obtain a microparticulate material.

The microparticulate material thus obtained was found to be able to super-adsorb fluids, e.g. water in an amount of from 3 to 6 times its dry weight. Also, it was found that the material is doing so very swiftly. Without wishing to be bound to any particular theory, this is believed due to the inherent capillary porosity of the material, which allows wicking of a fluid.

Surprisingly, it was found that the cellulose active material particles as such inherently have good antiviral activity against certain viruses, particularly enveloped viruses, such as COVID and influenza viruses. Enveloped viruses typically have an envelope comprising a lipid bilayer.

This is in particular relevant since it has proven difficult to produce an effective disinfectant that does not readily wash out of the material, in particular when subjected to an industrial or household detergents and washing and drying processes. Hence "wash-out", or leaching usually occurs, which reduces effectiveness and may cause irritation, or infections. This is a general problem where absorptive packings are placed in contact with significant possibility for dangerous pathogen load, e.g. viral load, or bacterial growth.

In addition, due to the globalization of transport, the emergence of new diseases and pandemics, the uses for a technology that imparts a essentially non-leaching re-useable antimicrobial modification to a variety of materials is duly recognized. Specific areas of use in are described below herein.

And last but not least, sustainable materials would be desired which may simply be subjected to compost preparations, preferably after extraction of valuable antimicrobial components, metals and the like.

Production of the Superabsorbent cellulose active material particles: The absorbent cellulose active material particles can be formed using any suitable means. Preferably, water or other liquid is not added to the plant material prior to comminution to form the particles. Thus, the plant material is not in the form of a slurry or suspension during the comminution step. Thus the process can include a step of comminuting plant material in the absence of liquid to form particles of plant material. Optionally, the plant material contains less than 30 wt.% water prior to comminution, for example contains less than 20 wt.% water, for example contains less than 15 wt.% water. In some embodiments, the plant material can be dried (e.g. at ambient temperature or at higher temperatures) before being formed into particles. The comminuted material can be screened to select particles of the desired size.

The particles of plant material can be formed by grinding or milling. For example, the plant material can be processed in a mill or using a grinding apparatus such as a classifier mill to provide particles of the required diameter size.

Preferably, a combination of a mechanically acting mill, i.e. one where the plant materials is crushed and turn apart and thus comminuted between actors, and a subsequent particle sizing is employed, e.g. by gravity or density, or sieving. However, the apparatus used to produce the particles from the plant material is not particularly critical to the successful operation of the process.

Methods for comminuting are not limited in particular, and include, for example, methods by a ball mill, a rod mill, a hammer mill, an impeller mill, a high-speed mixer, attritor mills and/or a disk mill. Of these, preferred are attritor or cell mills, as described for instance in publication W02013/167851, or in U53131875, U53339896, US3084876, and U53670970. In an attritor mill, a high shear field for is attained causing attrition or size reduction of the solid particulate matter. A particularly useful cell mill, coupled with sieves, may be obtained from Atritor Limited, Coventry.

Particle Size and Particle Size Distribution: The particles of plant material used within the process of the present invention have a mean average diameter of from 75 p.m to 400 p.m, preferably of from 100 lam to 300 lam, more preferably of from 100 i.tm to 200 i.tm. The term "diameter" refers to the measurement across the particle from one side to the other side. One skilled in the art would recognise the particles would not be perfectly spherical, but may be near-spherical, ellipsoid, disc-shaped, or even of irregular shape. One skilled in the art would also be aware that a range of diameters would be present within the starting material. To obtain the benefits of the present invention, it is not necessary to meticulously exclude very small quantities of particles which fall outside the stated particle diameter size. However, inclusion of particles of different diameter sizes within the starting material can, in some circumstances, adversely affect the quality of the end product.

Optionally, at least 60% by volume of the particles have a diameter of from 75 pm to 400 p.m, for example at least 70% by volume of the particles have a diameter of from 75 pm to 500 p.m, or at least 80% by volume of the particles have a diameter of from 75 p.m to 400 p.m, or at least 85% by volume of the particles have a diameter of from 75 pm to 400 pm, or at least 90% by volume of the particles have a diameter of from 75 p.m to 400 pm, or at least 95% by volume of the particles have a diameter of from 75 pm to 400 pm, or even at least 98% by volume of the particles have a diameter of from 75 pm to 400 pm. Conveniently 99% by volume of the particles have a diameter of from 75 pm to 400 pm. In some circumstances it may be advantageous to ensure that substantially all of the particles have a diameter of from 75 pm to 400 pm.

It has been found that the greater the amount of particles by volume that have a diameter above 75 pm, the easier the process of manufacturing fabrics and the more stable the fabric is to repeated washing cycles. It has been found that the greater the amount of particles by volume that have a diameter below 400 pm, the more stable the fabric is to delamination on repeated washing cycles.

Particles of the required diameter and within the predetermined particle size distribution can be selected using known methods, including (but not limited to) sieving the particle mixture with one or more sieves of known sieve size.

For example, passing the material sample through a sieve having a mesh size of 300 pm will only allow particles having a particle diameter of 300 pm of less to pass through. The sieved material can then be sieved again using a sieve having a smaller mesh size, for example a mesh size of 100 pm. The particles retained on the smaller mesh (i.e. which do not pass through) will have a particle size distribution of 200 pm and range in size from 100 pm to 300 p.m. Of course, sieves of alternative sieve size and in different combinations can be used to obtain any required particles diameter size range and particle size distribution. Alternatively, a classifier mill or other suitable means can be used to select particles of the required particle size and size distribution.

The cellulose active material particles may be washed, or, if desired, subjected to aqueous alkaline treatment followed by neutralisation of the hydrated mixture to form a washed hydrated mixture.

As indicated above, the cellulose active material particles can be washed in one or more washing steps. Typically, washing requires the cellulose material to be separated from the liquid fraction, and then re-suspended (optionally with agitation or stirring) in clean liquid, such as water.

The washing step essentially removes any excess reagent, and also any soluble by-products formed in the first step.

The step of separating the cellulose-containing material from the liquid fraction can be achieved using any suitable apparatus or process, including without limitation filtration (simple or vacuum filtration), centrifugation, membrane filtration etc. A woven filter can be used.

Alternatively a mesh filter can be used. Optionally, where filtration is used during the washing step, the filter has a pore size of 200 p.m or less, for example has a pore size of 100 p.m to 200 pm. A smaller pore size can also be used.

Optionally, the washing step, and neutralising step if present, is conducted in a manner which is compatible with a continuous manufacturing process. For example a filter at an angle of approximately 450 to the horizontal may advantageously be used, with the material to be filtered being dropped onto the filter from above so that liquid drains through the filter whilst solids are retained on the upper surface of the filter. The angle of the filter cause these retained solids to slide gently down the filter's upper surface onto a belt, or into a hopper or other receptacle ready for further processing. Alternatively a belt filter press can be used.

The cellulose active material particles may optionally be produced with step (d): Once the washing step is complete (including any optional neutralising steps), the obtained material may be isolated, and water removed. The material may be dried to touch dryness; e.g. comprising a water content equivalent to exposure of dry material to average air humidity; or dried further and package under exclusion of air humidity. Methods for drying are well-know, and include drying cylinders, rotating drums, belts and the like, typically heated by superheated steam or hot air; and also may include reduced pressure (vacuum drying). Preferred is heat drying under reduced pressure. Drying may preferably be done by subjecting the materials to air flow at elevated temperatures in rotating and heated drying drums, evaporating residual water and constituents volatile at the conditions. Conventional drying systems apply a so-called high-temperature drying, whereas alternative drying methods make use of indirect drying by means of superheated steam using a fluidized-bed method.

Additionally, the materials, whether obtained in step (d) or (e), may be modified by adding functional materials, e.g. additional antimicrobial compounds; colouring or pigmentation, or any other useful modifications, such as shaping or compressing into certain shapes or products, optionally with packaging.

Step e: After the washing step or optionally after step (d), the obtained the microparticles are contacted with an antimicrobial agent precursor under conditions inducive of the formation, attachment or binding of an antimicrobial agent.

Nanoparticle functionalised cellulose active material particles: In one embodiment, the and functionalised cellulose active material particles are provided as cellulose active material particles functionalised with antimicrobial nanoparticles, so as to provide an antimicrobial agent.

The antimicrobial nanoparticles may be selected from any nanoparticular material wherein 95 wt.% of the particles have a mean average diameter of 1-250 nm. The antimicrobial nanoparticles are bound to the surface of the fibres of the microparticles. It has been surprisingly found that nanoparticles bound to the cellulose active material do not de-attach from the cellulose active material under conditions emulating washing, even at 70°C. Without wishing to be bound by theory, it is believed that the nanoparticles physical incorporation within the fibrous network of the cellulose active material particles provides additional protection from physical ablation of the nanoparticles during washing.

Preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), gold nanoparticles [AuNPs] or copper nanoparticles (CuNPs). More preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), or copper nanoparticles (CuNPs).

Most preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs).

Optionally, the and functionalised cellulose active material particles may have been prepared from antimicrobial nanoparticles that were pre-formed and contacted with the microparticles to bind the antimicrobial nanoparticles to the microparticles so as to form an antimicrobial agent. The preformed antimicrobial nanoparticles therefore act as an antimicrobial agent precursor and by binding to the fibres of the microparticles form an antimicrobial agent.

This can be achieved by immersing the microparticles into a colloidal suspension bearing the preformed nanoparticles, followed by isolation of the nanoparticle-binding microparticles by filtration and washing of said isolated nanoparticle-binding microparticles. Preferably, the nanoparticles are provided as an aqueous solution.

Preferably, the pre-formed antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), gold nanoparticles [AuNPs] or copper nanoparticles (CuNPs). More preferably, the pre-formed antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs) or copper nanoparticles (CuNPs). Most preferably, the pre-formed antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs).

Preferably, the functionalised cellulose active material particles are those in which the antimicrobial nanoparticles have been formed in-situ in the cellulose active material particles. Here the nanoparticle pre-cursors act as an antimicrobial agent precursor and by forming nanoparticles at the surface of the fibres of the cellulose active material particles form an antimicrobial agent. Suitable nanoparticle pre-cursors may be selected from known nanoparticle precursors, such as copper salts, silver salts or gold salts. Particularly favoured nanoparticle precursors are copper sulfate (CuSO4), copper acetate (Cu(OAc)2), silver nitrate (AgNO3) and the chlorides of gold, including gold (Ill) chloride (Au2CI6), chloroauric acid (FlAuC14) and gold (i) chloride (AuCI), preferably copper sulfate (CuSO4), silver nitrate (AgNO3) and chloroauric acid (HAuC14), most preferably silver nitrate (AgNO3).

Forming antimicrobial nanoparticles in-situ confers the advantage of particularly great resistance of the thereby formed nanoparticles to "washing-out" or leaching from the material. Without being bound by theory, it is believed that formation of the nanoparticles in-situ may result in the nanoparticles forming within the network of cellulosic fibres of the microparticles, thereby physically trapping the fully formed nanoparticles within the network.

The nanoparticle precursors may be provided as a solution, preferably as an aqueous solution. Preferably, the nanoparticle precursors are provided as a 0.01-50 micromolar (mMol dm-3) solution on the basis of the metal containing compound, more preferably 0.1-20 micromolar, most preferably 1-10 micromolar.

Surprisingly, the inventors found that no reducing agent was required to form nanoparticles in situ when contacted with the microparticles. Optionally, additional reducing agents may be used to expedite nanoparticle formation.

The solution of nanoparticle precursors may be contacted with the microparticles by immersion of the microparticles in a solution of the nanoparticle precursors. Alternatively, a solution of nanoparticle precursors may be spray coated onto the microparticles.

Preferably, nanoparticle formation is performed under illumination with light, preferably light of a wavelength of 300-500 nm, more preferably 350-450 nm, yet more preferably 380-420 nm, most preferably 390-400 nm.

Preferably, nanoparticle formation is conducted at from 0 to 150 °C, more preferably from 10 to 110 °C, yet more preferably from 15 to 60 °C and most preferably from 20 to 30 C. Preferably, nanoparticle formation is conducted as part of a continuous process, wherein the microparticles prepared by steps described above are contacted with at least one. For example, the microparticles prepared by steps described above may be spray coated with a solution of nanoparticle precursors. Suitable nanoparticle pre-cursors may be selected from known nanoparticle precursors, such as copper salts, silver salts or gold salts. Particularly favoured nanoparticle precursors are copper sulfate (CuSO4), copper acetate (Cu(OAc)2), silver nitrate (AgNO3) and the chlorides of gold, including gold (Ill) chloride (Au2CI6), chloroauric acid (HAuC14) and gold (i) chloride (AuCI), preferably copper sulfate (CuSO4), silver nitrate (AgNO3) and chloroauric acid (HAuC14), most preferably silver nitrate (AgNO3). The particularly favoured nanoparticles may be provided as an aqueous solution.

More preferably, nanoparticle formation is conducted as part of a continuous process, wherein the microparticles prepared by steps described above are contacted with at least one nanoparticle precursor followed by irradiation with light of a wavelength of 300-500 nm. Suitable nanoparticle pre-cursors may be selected from known nanoparticle precursors, such as copper salts, silver salts or gold salts. Particularly favoured nanoparticle precursors are copper sulfate (Cu504), copper acetate (Cu(OAc)2), silver nitrate (AgNO3) and the chlorides of gold, including gold (III) chloride (Au2CIG), chloroauric acid (HAuC14) and gold (i) chloride (AuCI), preferably copper sulfate (Cu504), silver nitrate (AgNO3) and chloroauric acid (HAuC14), most preferably silver nitrate (AgNO3). The particularly favoured nanoparticles may be provided as an aqueous solution.

nanoparticle formation is performed under illumination with light, preferably light of a wavelength of 300-500 nm, more preferably 350-450 nm, yet more preferably 380-420 nm, most preferably 390-400 nm.

Most preferably, nanoparticle formation is conducted as part of a continuous process, wherein the microparticles prepared by steps described above are contacted with an aqueous solution of silver nitrate (AgNO3), followed by irradiation with of a wavelength of 300-500 nm.

Peptide and/or proteins functionalised cellulose active material particles: In an alternative embodiment, the functionalised cellulose active material particles ARE cellulose active material particles functionalised with antimicrobial peptide and/or proteins.

Preferably, the peptides and/or proteins are antimicrobial. More preferably the antimicrobial peptides or proteins comprise peptides or proteins having an amino acid sequence selected from the group consisting of AU1, AU2, AU3, 1037, LF1-11, KR12, lactoferrampin, FK-16 and Dispersin B (SEQ ID NOs 1 to 9). AU1 has an amino acid sequence of SEKLFFGASL (SEQ ID NO 1). AU2 has an amino acid sequence of SEKLWWGASL (SEQ ID NO 2). AU3 has an amino acid sequence of GASLWWSEKL (SEQ ID NO 3). Lactoferrampin has an amino acid sequence of WNLLRQAQEKFGKDKSP (SEQ ID NO 7). FK-16 has an amino acid sequence of FKRIVQRIKDFLRNLV (SEQ ID NO 8) or FKRIVQRIKDFLRNLV-amide. 1037 has an amino acid sequence of KRFRIRVRV (SEQ ID NO 4) or KRFRIRVRV-amine. The amino acid sequences and their SEQ ID NOs of the preferred antimicrobial peptides and proteins according to the invention are set out in Table A below.

Table A: Amino acid sequences and SEQ ID NOs of the preferred antimicrobial peptides and proteins according to the invention SEQ ID NO Name Sequence 1 AU1 SEKLFFGASL 2 AU2 SEKLWWGASL 3 AU3 GASLWWSEKL 4 1037 KRFRIRVRV LF1-11 GRRRSVQWCAV 6 KR12 KRIVQRIKDFLR 7 Lactoferrampin WNLLROAQEKFGKDKSP 8 FK-16 FKRIVQRIKDFLRNLV 9 Dispersin B NCCVKGNSIYPQKTSTKQTGLM LDIARFIFYSPEVIKSFIDTISLSGG NFLHLHFSDHENYAIESHLLNQRAENAVQGKDGIYINPYTGKPFLS YRQLDDIKAYAKAKGIELIPELDSPNH MTAIFKLVQKDRGVKYLQG LKSRQVDDEIDITNADSITFMQSLMSEVIDIFGDTSQHFHIGGDEF GYSVESNHEFITYANKLSYFLEKKGLKTRMWNDGLIKNTFEQINPN I EITYWSYDGDTQDKNEAAERRDM RVSLPELLAKGFTVLNYNSYYL YIVPKASPTFSQDAAFAAKDVIKNWDLGVWDGRNTKNRVQNTH EIAGAALSIWGEDAKALKDETIQKNTKSLLEAVIHKTNGDE Dispersin B is a family 20 p-hexosaminidase originating from the oral pathogen Aggregatibacter actinomycetemcomitans, also known as Actinobacillus actinomycetemcomitans.

Preferably, the peptides and/or proteins have a metal binding domain, more preferably a copper, silver or gold binding domain, most preferably a silver binding domain.

In an alternative embodiment, the functionalised cellulose active material particles ARE cellulose active material particles functionalised with both (i) antimicrobial nanoparticles and (ii) antimicrobial peptides and/or proteins.

The antimicrobial nanoparticles may be selected from any nanoparticular material wherein 95 wt.% of the particles have a mean average diameter of 1-250 nm. The antimicrobial nanoparticles are bound to the surface of the fibres of the microparticles. It has been surprisingly found that nanoparticles bound to the cellulose active material do not de-attach from the cellulose active material under conditions emulating washing, even at 70 C. Without wishing to be bound by theory, it is believed that the nanoparticles physical incorporation within the fibrous network of the cellulose active material particles provides additional protection from physical ablation of the nanoparticles during washing.

Preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), gold nanoparticles [AuNPs] or copper nanoparticles (CuNPs). More preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs) or copper nanoparticles (CuNPs).

Most preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs). Optionally, the antimicrobial nanoparticles may be pre-formed and contacted with the microparticles to bind the antimicrobial nanoparticles to the microparticles so as to form an antimicrobial agent. The preformed antimicrobial nanoparticles therefore as an antimicrobial agent precursor and by binding to the fibres of the microparticles form an antimicrobial agent.

Preferably, the antimicrobial nanoparticles may be formed in-situ. Here the nanoparticle pre-cursors act as an antimicrobial agent precursor and by forming nanoparticles at the surface of the fibres of the microparticles form an antimicrobial agent. Suitable nanoparticle pre-cursors may be selected from known nanoparticle precursors, such as copper salts, silver salts or gold salts. Particularly favoured nanoparticle precursors are copper sulfate (CuSO4), copper acetate (Cu(OAc)2), silver nitrate (AgNO3) and the chlorides of gold, including gold (Ill) chloride (Au2CI6), chloroauric acid (HAuC14) and gold (i) chloride (AuCI), preferably copper sulfate (CuSO4), silver nitrate (AgNO3) and chloroauric acid (HAuC14), most preferably silver nitrate (AgNO3).

Forming antimicrobial nanoparticles in-situ confers the advantage of particularly great resistance of the thereby formed nanoparticles to "washing-out" or leaching from the material.

Without being bound by theory, it is believed that formation of the nanoparticles in-situ may result in the nanoparticles forming within the network of cellulosic fibres of the microparticles, thereby physically trapping the fully formed nanoparticles within the network.

The nanoparticle precursors may be provided as a solution, preferably as an aqueous solution. Preferably, the nanoparticle precursors are provided as a 0.01-50 micromolar (mMol dm 3) solution on the basis of the metal containing compound, more preferably 0.1-20 micromolar, most preferably 1-10 micromolar.

Preferably, nanoparticle formation is conducted at from 0 to 150 °C, more preferably from 10 to 110 °C, yet more preferably from 15 to 60°C and most preferably from 20 to 30°C.

In a particularly favoured combination, the peptides and/or proteins have a copper, silver or gold binding domain and the nanoparticles are formed in-situ from corresponding a copper, silver or gold containing nanoparticle precursor, of which the combination of peptides and/or proteins having a silver binding domain and a silver containing nanoparticle precursor is most favoured. Without being bound by theory, it is believed that the metal binding domain of the peptide and/or protein and the nanoparticle act to enhance "attachment" of the peptides and/or proteins to the cellulose-containing microporous superabsorbent composition. The cellulose-containing microporous superabsorbent composition comprising both (i) antibiofilm/antibacterial peptides/proteins and (ii) antimicrobial nanoparticles surprisingly demonstrated synergistic antibacterial properties.

Step f: After step (e) the antimicrobially modified microporous superabsorbent composition is isolated. This can be achieved by isolation of the antimicrobially modified microporous superabsorbent composition by filtration, followed by washing.

Optional step g: a film may be formed from the antimicrobially modified microporous superabsorbent composition.

In preferable embodiment, the functionalised cellulose active material particles are those obtained from a process comprising the following step: (1) performing the process for preparing an antimicrobial nanoparticle-containing cellulose-containing microporous superabsorbent composition according to any of the suitable embodiments describes above; (2) performing the process for preparing an antimicrobial protein-containing and/or peptide-containing cellulose-containing microporous superabsorbent composition according to any of the suitable embodiments describes above; and (3) blending the antimicrobial nanoparticle-containing cellulose-containing microporous superabsorbent composition and the antimicrobial protein-containing and/or peptide-containing cellulose-containing microporous superabsorbent composition.

This embodiment advantageously allows for fabrics comprising both nanoparticle and protein and/or peptide functionalised cellulose active material particles, whose antimicrobial behaviour is enhanced by the synergistic action of two modes of antimicrobial action.

Typically, the functionalised cellulose active material particles used in the present invention need only be added in surprisingly small quantities to achieve a different effect of the antimicrobial properties of the material into which it has been incorporated. For example the cellulose-containing material formed in the process of the present invention need only be added in an amount of from 10 wt%, for example 8 wt%, for examples wt%, for example 3 wt%, for example 2 wt% or even 1 wt% or even less. In some applications the cellulose-containing material formed in the process of the present invention need only be added in an amount of 0.5 wt% or less.

One effect of utilising an adhesive layer comprising functionalised cellulose active material particles is that the resultant fabric comprises a water absorbent material, which helps wick moisture. This advantageously results in fabrics that are more comfortable to wear. An additional effect is that microbes within an aerosolised droplet (such as COVID-containing droplets that arise from coughing) on contacting the fabric are absorbed by the functionalised cellulose active material particles, and thus mechanically brought into proximity with the antimicrobial agents of the functionalised cellulose active material particles.

Due to the distributed particulate nature, swelling of functionalised cellulose active material of the functionalised cellulose active material particles with have a mean average diameter of from 75 pm to 400 p.m on absorbing water does not lead to de-adhesion of the functionalised cellulose active material particles from the fabric material. This advantageously results in fabrics that are more comfortable to wear and have a long life span. Without being boun by theory, it is believed that repeated expansion of the functionalised cellulose active material on water absorption and contraction of the functionalised cellulose active material on water desorption exerts forces on the materials encompassing such active material, and if the forces are excessive over multiple cycles of water absorption and desorption, such as might occur if the particle size is too great, may cause delamination of the first fabric layer from the second fabric layer.

The functionalised cellulose active material particles will lose water on drying, either slowly by evaporation under ambient conditions (such as on a drying rack) or more quickly when dried (such as in a tumble drier).

In one embodiment, the functionalised cellulose active material particles are functionalised with antimicrobial nanoparticles. 95 wt.% of these antibacterial nanoparticles have a size of 1-250 nm.

The antimicrobial nanoparticles may be selected from any nanoparticular material wherein 95 wt.% of the particles have a size of 1-250 nm.

The antimicrobial nanoparticles are bound to the surface of the fibres of the cellulose active material particles. It has been surprisingly found that nanoparticles attached to the cellulose active material do not de-attach from the cellulose active material under conditions emulating washing, even at 70 C. Without wishing to be bound by theory, it is believed that the nanoparticles physical incorporation within the fibrous network of the cellulose active material particles provides additional protection from physical ablation of the nanoparticles during washing.

In one embodiment, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), gold nanoparticles [AuNPs] or copper nanoparticles (CuNPs). More preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), or copper nanoparticles (CuNPs). Most preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs).

One effect of utilising a fabric with an adhesive layer comprising cellulose active material particles functionalised with antimicrobial nanoparticles is that the fabric itself is antimicrobial as assessed by microbial challenge testing evaluated by the protocol of ISO 18184 (2019), the protocol of ISO 20743 (2021) and/or the protocol of ISO 13629 (2014).

In an alternative embodiment, the cellulose active material particles are functionalised with antimicrobial proteins.

One advantage of utilising an adhesive layer comprising protein and/or peptide functionalised cellulose active material particles is that the resultant fabric kills bacteria and viruses.

The fabric according to the first aspect of the invention has a filtration efficiency (in %).

Filtration depends on the filtration efficiency (in %), the type of challenge particle (oils, solids or droplets containing viruses/bacteria) and the particle size. Depending on the fabrics used, filtration and breathability can complement or work against one another. Filtration is dependent on the tightness of the weave, fibre or thread diameter. Non-woven materials used for disposable masks are typically manufactured using processes to create polymer fibres that are typically thinner than natural fibres such as cotton and that are held together by partial melting.

The fabric preferably has a filtration efficiency of 70-100% with a particle size of 3 pm, more preferably 80-100%, even more preferably 90-100%, yet more preferably 95-100%, most preferably 99-100% with a particle size of 3 pm.

More preferably the fabric has a filtration efficiency of 95-100% with a particle size of 2 p.m, more preferably 80-100%, yet more preferably 90-100%, even more preferably 95-100%, most preferably 99-100%.

Even more preferably the fabric has a filtration efficiency of 70-100% with a particle size of 1 pm, more preferably 80-100%, yet more preferably 90-100%, even more preferably 95-100%, most preferably 99-100%.

Yet more preferable still, the fabric has a filtration efficiency of 95-100% with a particle size of 0.3 pm, more preferably 99-100%, most preferably 99.97-100%.

The fabric according to the first aspect of the invention has a breathability. This is given in air permeability given in Pascals (Pa) or, normalized to the cm2 Pa/cm'. High breathability values (high resistance) mean the fabric is resistant to the passage of air through the fabric.

Preferably, the fabric has an air permeability below 65 Pa/cm'. Preferably, the air permeability is below 60 Pa/cm', more preferably is below 50 Pa/cm2, even more preferably is below 40 Pa/cm', yet more preferably still is below 30 Pa/cm' and most preferably is below 20 Pa/cm2. Lower values indicate better breathability.

An air permeability value below 60 Pa/cm2 provides a fabric ideally suited for face masks.

An air permeability value below 40 Pa/cm2 provides a fabric ideally suited for surgical masks. An air permeability value below 20 Pa/cm' provides a fabric ideally suited for paediatric masks.

Preferably, the fabric is splash resistant, with no liquid penetration according to EN 14683:2019+AC:2019.

Preferably, the fabric is antiviral as defined by ISO 18184.

Preferably, the fabric is antibacterial as defined by ISO 20743.

Preferably, the fabric is antifungal as defined by ISO 13629.

More preferably, the fabric possesses full antimicrobial activity (antiviral, antibacterial and antifungal activity as defined above).

Preferably, the fabric is biodegradable as defined by EN 13432 standard "Requirements for packaging recoverable through composting and biodegradation -test scheme and evaluation criteria for the final acceptance of packaging".

Preferably, the fabric is reusable. For a fabric to be reusable, it must still fulfil the minimum breathability and filtration requirements above after washing for 5 cycles.

Preferably, the fabric is not elastic. Elastic fabrics are sensitive to washing at high temperatures and may degrade over time.

Preferably, the fabric is coated with compounds such as wax to provide a water impermeable outer coating. This increases the barrier properties and renders the fabric fluid resistant.

A further aspect of the invention relates to a method of manufacturing a fabric as above comprising the steps of providing a first fabric layer; depositing a mixture of particulate adhesive and functionalised cellulose active material onto the first fabric layer; depositing a second fabric layer onto the coated surface of the first fabric layer; and heating the laminate to adhere the first fabric layer to the second fabric later.

Preferably, the step of depositing a mixture is scatter coating deposition.

Preferably, the heating step is performed with application of a force, applied by a roller, wherein the force is from 9800 N to 490000 N, more preferably 49000 N to 245000 N, yet more preferably 78400 N to 215600 N and most preferably 88200 N to 196000 N. Preferably, the heating step is performed with a roller at a temperature of from 90°C to 250 °C, more of from 120°C to 220 °C, yet more preferably of from 140 to 200°C and most preferably of from 150 °C to 180 °C.

In a particularly favourable embodiment, the heating step is performed with a roller at a temperatures of from 150 °C to 180 T which applies a force of from 88200 N to 196000 N. Preferably the method is a roll-to-roll method, more preferably a roll-to-roll process wherein the heating step is a localised heating step.

Uses of the Antimicrobial Fabric: The present materials are superabsorbent with an advantageous liquid storage capacity combined with a liquid wicking efficacy. Hence, these superabsorbent materials are economically viable for use in absorbent articles and are fully biodegradable, so that disposal of the absorbent articles used is environmentally friendly.

The term "absorbent article" generally refers to a device that can absorb and contain fluids. As used herein, absorbent articles include baby sanitary products such as diapers, baby wipes, bowel training pants and other disposable garments; Feminine hygiene products such as sanitary napkins, wipes, sanitary pads, pantiliners, panty shields, tampons and tampon applicators; Adult sanitary products such as wipes, pads, incontinence products, urine shields, furniture pads, bed pads and head bands; Public, industrial and household products such as wipes, covers, filters, paper towels, bath tissues and facial tissues; Nonwovens, such as nonwoven rolls; Home comfort products, such as pillows, pads, cushions and masks; And professional and consumer hygiene products, including but not limited to surgical drapes, hospital gowns, wipes, wraps, covers, bands, filters and disposable garments.

The absorbent materials according to the invention, optionally modified, advantageously may be used in wound dressing, sanitary pad, a tampon, an intrinsically antimicrobial absorbent dressing, a diaper, toilet paper, a sponge, a sanitary wipe, food preparation surfaces, gowns, gloves, surgical scrubs, sutures, needles, sterile packings, floor mats, lamp handle covers, burn dressings, gauze rolls, blood transfer tubing or storage container, mattresses, applicators, exam table coves, head covers, cast liners, splint, paddings, lab coats, air filters for autos, planes or HVAC systems, military protective garments, face masks, devices for protection against biohazards and biological warfare agents, food packaging material, and other materials that would profit from biodegradable and antimicrobial properties.

The term "comprising" as used herein means consisting of, consisting essentially of, or including and each use of the word "comprising" or "comprises" can be independently revised by replacement with the term "includes", "consists essentially of or "consists of" . In connection with the care and treatment of wounds, the term "wound" is meant to include burns, pressure sores, punctures, ulcers and the like. For a long time, one critical aspect of wound care has been the consideration of the requirements of the epithelium, i. e., that area of new cell growth directly peripheral to the wound which is formed during the healing process, so that healing is facilitated.

Use of the fabric as detailed above in the manufacture of personal protective equipment. A further aspect of the invention relates to the use of the fabric as described above in the manufacture of personal protective equipment.

A further aspect of the invention relates to face masks comprising the fabric as described above.

Such a face mask must provide a minimum standard of filtration and be breathable. Filtration depends on the filtration efficiency (in %), the type of challenge particle (oils, solids, droplets containing bacteria) and the particle size. Depending on the fabrics used, filtration and breathability can complement or work against one another. Filtration is dependent on the tightness of the weave, fibre or thread diameter. Non-woven materials used for disposable masks are manufactured using processes to create polymer fibres that are typically thinner than natural fibres such as cotton and that are held together by partial melting.

The mask has a filtration efficiency of 70-100% with a particle size of 3 pm, preferably 80- 100%, more preferably 90-100%, yet more preferably 95-100%, even more preferably 99-100%, most preferably 99.97-100% with a particle size of 3 pm.

Preferably the mask has a filtration efficiency of 70-100% with a particle size of 2 pm, more preferably 80-100%, yet more preferably 90-100%, even more preferably 95-100%, even more preferably 99-100%, most preferably 99.97-100% with a particle size of 2 pm.

More preferably the mask has a filtration efficiency of 70-100% with a particle size of 1 p.m, more preferably 80-100%, yet more preferably 90-100%, even more preferably 95-100%, more preferably still 99-100%, most preferably 99.97-100% with a particle size of 1 pm.

Preferably, the mask has a Bacterial Filtration Efficiency (BFE) of 95-100% as determined according to EN 14683:2019+AC:2019 "European standard for face masks". This is a measure of the ability of the face mask to filter out bacteria on exhalation so that they are not released into the user's surroundings (BFE), (%). More preferably, the mask has a BFE of 98-100% Breathability is the difference in pressure across the mask. This quantified by air permeability given in Pascals (Pa) or, normalized to the cm2 of surface area, Pa/cm2. The lower the value, the easier it is to breathe whilst wearing the mask. High breathability values (high resistance) can cause bypass of the mask. This results in unfiltered air leaking out the sides or around the nose if that is the easier path, with consequent increased risk of infection transmission from the mask wearer to others.

Excessive air resistance can lead during exhalation to a build-up of pressure behind the mask, which may tend to lift the mask from the wearer's race and permit bacteria to escape, defeating the purpose of the mask. Masks with high air resistance can also become uncomfortable to wear, especially if for prolonged periods.

Breathability over the whole face mask is below 65 Pa/cm2. Preferably, the breathability is below 60 Pa/cm2, more preferably is below 50 Pa/cm2, even more preferably is below 40 Pa/cm2, yet more preferably still is below 30 Pa/cm2 and most preferably is below 20 Pa/cm2.

Lower values indicate better breathability.

Air permeability values are obtained according to ISO 9237.

A breathability value below 20 Pa/cm' is ideally suited for paediatric uses.

Splash resistance pressure is the ability of the face mask to withstand the penetration of liquid splashes (kPa). Preferably, the face mask is splash resistant with a splash resistance pressure of over a 16,0 kPa as measured by EN 14683:2019+AC:2019, more preferably with no liquid penetration according to EN 14683:2019+AC:2019.

Preferably, the face mask is antiviral as defined by ISO 18184. Also, preferably, the face mask is antibacterial as defined by ISO 20743. yet further, preferably, the face mask is antifungal as defined by ISO 13629.

Preferably, the face mask is microbially clean with a cleanliness of a 30 cfu/g. Microbial cleanliness documents cleanliness in the manufacturing process (cfu/g), as determined in EN 14683:2019+AC:2019.

More preferably, the face mask possesses full antimicrobial activity (antiviral, antibacterial and antifungal activity as defined above).

Particularly preferable masks according to the invention possess a bacterial filtration efficiency (BFE) of 95-100%, breathability value of from 0 to 40 Pa/cm', and a cleanliness of a 30 cfu/g.

Particularly preferable masks according to the invention possess a bacterial filtration efficiency (BFE) of 98-100%, breathability value of from 0 to 40 Pa/cm2, and a cleanliness of a 30 cfu/g.

Particularly preferable masks according to the invention possess a bacterial filtration efficiency (BFE) of 98-100%, breathability value of from 0 to 60 Pa/cm2, splash resistant with a splash resistance pressure of over a. 16,0 kPa, and a cleanliness of 30 cfu/g.

In one particularly preferable embodiment, masks according to the invention comply with N95 standard according to United States NIOSH-42CFR84 standard.

In an alternative particularly preferable embodiment, masks according to the invention comply with the FFP1 standard according to EN 149(2009).

In an alternative particularly preferable embodiment, masks according to the invention comply with the FFP2 standard according to the European standard EN 149(2009).

In an alternative particularly preferable embodiment, masks according to the invention comply with the FFP3 standard according to EN 149(2009).

In an alternative particularly preferable embodiment, masks according to the invention comply with the KN95 standard according to Chinese standard G8262-2006.

In an alternative particularly preferable embodiment, masks according to the invention comply with the P2 standard according to Australian/New Zealand standard AS/NZA 1716 (2012). In an alternative particularly preferable embodiment, masks according to the invention comply with the Korea 1st class standard according to Korea KMOEL-2017-64.

In an alternative particularly preferable embodiment, masks according to the invention comply with the DS2 standard according to Japanese standard JMHLW-Notification-214, 2018.

In an alternative particularly preferable embodiment, masks according to the invention comply with the PFF2 standard according to Brazilian standard ABNT/NBR 13.698.2011.

In an alternative particularly preferable embodiment, masks according to the invention comply with the standard according to Russian GOST R 12.4.191-2011.

Preferably, the mask is biodegradable as defined by EN 13432 standard "Requirements for packaging recoverable through composting and biodegradation -test scheme and evaluation criteria for the final acceptance of packaging".

Preferably, the face mask is reusable. For a face mask to be reusable, it must still fulfil the minimum breathability and filtration requirements above after washing for 5 cycles.

Preferably, the fabric is not elastic. It is preferable not to select elastic material to make masks as the mask material may be stretched over the face, resulting in increased pore size and lower filtration through multiple usage. Additionally, elastic fabrics are sensitive to washing at high temperatures thus may degrade over time.

Preferably, the face mask is coated with compounds such as wax to provide a water impermeable outer coating. This increases the barrier properties and renders the mask fluid resistant.

Preferably, the face mask does not comprise valves or vents to allow the movement of air outward from the mask when in use (during exhalation).

Preferably, the face mask is designed to accommodate the anthropometric considerations of facial dimensions according to ISO/TS 16976-2. This ensures a good fit for the face mask for the greatest majority of users.

Preferably, the face mask has a flat-fold or duckbill shape.

Preferably, the face mask has a strap strength of from 40 to 120 N, more preferably of from 45 to N, most preferably a strap strength of from 50 to 80 N. A further aspect of the invention relates to the use of the fabric as described above in the manufacture of sports clothing.

Any modifications and/or variations to described embodiments that would be apparent to one of skill in art are hereby encompassed. Whilst the invention has been described herein with reference to certain specific embodiments and examples, it should be understood that the invention is not intended to be unduly limited to these specific embodiments or examples.

Preferred or alternative features of each aspect or embodiment of the invention apply mutatis mutandis to each aspect or embodiment of the invention (unless the context demands otherwise).

The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The description that follows more particularly exemplifies illustrative embodiments.

The present invention is now further described with reference to the following non-

limiting examples.

Examples Example 1

Sugar-beet pellets were subjected to a milling step in an attritor mill, selecting a composition comprising at a weight average particles size of from 100 p.m to 300 p.m, and subsequently subjected to a water washing and drying step, to obtain a cellulose-containing microporous superabsorbent composition.

Example 2

Nanoparticle functionalised cellulose active material was prepared as described below. Silver nanoparticle [AgN13] functionalised cellulose active material g of the cellulose-containing microporous superabsorbent composition of example 1 were contacted with 700 mL of a 5 m M aqueous solution of AgNO3 at 25°C for two hours. The suspension was filtered, the retained solids then dried under a flow of air at 25°C for 12 hours. The dried material was then suspended in 700 mL of water at 25°C for two hours. The suspension was filtered, the retained solids then dried under a flow of air at 25 °C. The dried material was then washed with water three times. Each water wash consisted of suspending the solid material in 1400 mL of water for 10 minutes at 25 °C, followed by isolation of the solid by filtration. The isolated, thrice washed solid material was then dried under a flow of air at 25 °C for 12 hours.

Gold nanoparticle lAuNP1 functionalised cellulose active material The cellulose active material particles of Example 1(70 g) was treated with 700 mL of a 5 mM aqueous solution of HAuC14.3H20 at 25°C for two hours. The suspension was filtered, the retained solids then dried under a flow of air at 25°C. The dried material was then suspended in 700 mL of water at 25°C for two hours. The suspension was filtered, the retained solids then dried under a flow of air at 25 °C. The dried material was then washed with water three times. Each water wash consisted of suspending the solid material in 1400 mL of water for 10 minutes at 25 °C, followed by isolation of the solid by filtration. The isolated, thrice washed solid material was then dried under a flow of air at 25°C. ICP-MS analysis established 7500(±399) mg/kg of silver was incorporated into the material, which means approximately 80% of the fold present in the aqueous sold salt was incorporated into the material on an elemental basis.

Materials prepared according to the protocols above were digested in aqua regia (21% HC1/9% HNO3) and the resultant aqueous solution analysed in triplicate by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using a Perkin Elmer AVIO 500 in a laboratory accredited under ISO 17025. Samples were diluted if required to bring results within the calibration range. Standard and QC solutions were made from stocks traceable to NIS and the method utilises multi-point calibration with the following standards:10, 6,4, 2 and 1 ppm metal.

The results are reproduced in Table 1. ICP-MS analysis established 681(±11) mg/kg of silver was incorporated into the silver nanoparticle functionalised cellulose active material, which means approximately 12% of the silver present in the aqueous silver salt was incorporated into the material on an elemental basis. ICP-MS analysis established 7500(±399) mg/kg of gold was incorporated into the gold nanoparticle functionalised cellulose active material, which means approximately 80% of the gold present in the aqueous silver salt was incorporated into the material on an elemental basis.

The water absorbance of the cellulose active material particles of Example land the nanoparticle functionalised cellulose active material particles of Example 2 were determined.

The water absorption was characterized by a Water Holding Capacity (WHC) parameter, which was determined using the method described in Ashraf et al., Int. J. Agric. Biol., Vol. 14, No. 3, 2012. Samples were weighed out in centrifuge tubes, with a minimum sample weight of 0.5g. Water was added to each sample until the material was completely wet. The tubes were then centrifuged at 4000 RPM for 10 minutes. Following completion of centrifuge, the supernatant was discarded and swollen sample weighed. The WHC value was determined using the following calculation: WHC = (Ssw-Sw)/Sw, where Sw= dry sample weight and Ssw= sample weight after centrifugation. The maximal water absorbance of the silver nanoparticle [AgNP] functionalised cellulose active material particles was determined as approximately 6 g of water per g of AgNP functionalised cellulose active material particles (see Table 1). The water absorbance of the gold nanoparticle [AuNP] functionalised cellulose active material particles was determined as approximately 5 g of water per g of AgNP functionalised cellulose active material particles (see Table 1).

Table 1: Properties of antimicrobial cellulose-containing microporous superabsorbent compositions Material Example 1 Example 2 [AgNP] Example 2 [AuNP] Maximal water 4.957 6.145 4.967 absorbance [g(water)/g(material)] Water Holding 5.81 6.79 Not determined Capacity Silver (mg/kg) n/a 681(±11) 0 Gold (mg/kg) n/a 0 7500(±399) % incorporation of n/a 12 80 available metal into material

Example 3

Protein functionalised cellulose active material particles according to the invention were prepared as follows: General protocol: Functionalisation of TEMPO cellulose particulate material with proteins A 1% (w/v) gel of TEMPO oxidised cellulose particulate material was washed three times, wherein a wash consisted of adding water to the cellulose particulate material slurry to its original volume, vortexing the mixture to resuspend the mixture, centrifuging the mixture at 4200 g for 5 minutes and decanting the supernatant. The cellulose particulate material was washed three additional times with a carbonate buffer (0.1M NaHCO3 pH 8.3) in the same fashion as above. The washed cellulose particulate material was resuspended in carbonate buffer to obtain a 1.2% stock of functionalised cellulose particulate material.

Proteins and/or enzymes were added to the 1.2% stock of functionalised cellulose particulate material resulting in a mixture comprising 1% (w/v) cellulose particulate material. The mixture was incubated from several hours to up to 60 hours and yielded a stable integration or attachment of the proteins or enzymes to the cellulose particulate material.

The following proteins were added as follows: Calf intestinal phosphatase (CIP) at a stock concentration of 3000 U/mg (New England Biolabs, M0290S) was added at a concentration of 10 to 200 pg per ml of cellulose particulate material slurry (1% (w/v)). The mixture was incubated for 2 hours at room temperature (about 25 °C) and subsequently stored for future use in a 0.1M pH 8.3 carbonate buffer or phosphate buffered saline (PBS).

Invertase from bakers' yeast at a stock concentration of 300 U/mg (Sigma, 14504) was added at a concentration of 100 pg per ml of cellulose particulate material slurry (1% (w/v)). The mixture was incubated for about 16 hours and subsequently stored for future use in a 0.1M pH 4.5 acetate buffer.

GFP-SpyCatcher was added at a concentration of 25 pg to 2 mg per ml of cellulose particulate material slurry (1% (w/v)). The mixture was incubated for 16 hours or 60 hours and subsequently stored for future use in a 0.1M pH 8.3 carbonate buffer or phosphate buffered saline (PBS).

Dispersin B (DSPB) or Dispersin B containing a metal binding domain (AgDSPB) was added to cellulose particulate material slurry (1% (w/v)) that was not washed or contacted with carbonate buffer, and incubated for several hours. Functional attachment of CIP CIP was attached to functionalised cellulose particulate material according to Example 11 at a concentration of 0, 10, 20 or 40 pg/ml. The mixture was washed and centrifuged twice, after which the supernatants and composite material were assessed for functional attachment of CIP via a BCIP/NBT calorimetric assay. The calorimetric assay is a standard alkaline phosphatase activity assay wherein the substrates 5-bromo-4-chloro-3-indoly1 phosphate (BCIP) and nitro blue tetrazolium (NBT) are used to determine the activity of enzymes such as CIP via a calorimetric readout. It was determined by UV-VIS spectroscopic analysis that, although some of the CIP has not been attached as is evident from the supernatant colour change, CIP is attached to the cellulose particulate material.

Functional attachment of invertase: Invertase was attached to functionalised cellulose particulate material according to Example 11. The mixture was then washed three times with water according to Example 1 at a centrifugation of 4122 g and resuspended in water to restore volume equal to the initial volume of TEMPO oxidised cellulose particulate material (1% w/v). The mixture was washed a further three times as with water above, but instead with a 0.1 M pH 4.5 acetate buffer to obtain a 1% (w/v) slurry.

To the slurries, different amounts of sucrose was added (100-0.1 mg/ml final volume in reaction) and the conversion of sucrose into glucose and fructose was measured at OD 410 nm according to the manufacturer's protocols, with samples taken at different time points. It was seen that sucrose is converted into glucose and fructose thereby confirming the attachment of invertase to the cellulose particulate material.

Functional attachment of GFP-SpvCatcher: GFP-SpyCatcher was attached to functionalised cellulose particulate material according to Example 1. The mixture was washed several times in PBS to remove unbound components. It was determined by UV-VIS spectroscopic analysis that GFP-SpyCatcher is attached to the cellulose particulate material. The SpyCatcher motif contains a Histidine-tag for convenient analysis by for example standard Western Blotting techniques. Functional attachment of DSPB and AgDSPB: DSPB or AgDSPB were attached to cellulose particulate material according to Example 1. The mixture was washed three times in PBS. It was confirmed that DSPB and AgDSPB can attach robustly to non-and silver-metallised cellulose particulate material by western blotting. It was found that DSPB can bind at about 1 Ftgimm2 cellulose particulate material.

Example 4

Fabric according to the invention was manufactured as follows. A first fabric layer of 100% cotton plain weave (120 g) was provided. An adhesive film was deposited (65 g) as a mesh of fibres. Functionalised cellulose active material particles were scattered onto the adhesive film. A second fabric layer of 100% cotton plain weave (120 g) was placed on top of the first fabric layer so as to enclose the deposited adhesive layer and the functionalised cellulose active material particles. The combined layers were hot laminated at and 20 tonne pressure.

The resultant fabric was analysed by optical microscopy. As can be seen in Figure 1, the functionalised cellulose active material particles are enclosed between the two cotton layers and the two layers bonded together by the adhesive. The resultant fabric was found to have a relatively even distribution of functionalised cellulose active material particles. Further, the resultant fabric featured webbing bonds of melted adhesive material adhering fibres of the first fabric layer to fibres of the second fabric layer, without encapsulating the functionalised cellulose active material particles. The functionalised cellulose active material particles were demonstrated to be capable of absorbing water. The adhesion between the layers was found to be strong. Example 5 A first fabric layer of 100% cotton plain weave (120 g) was provided. A mixture of particulate adhesive and functionalised cellulose active material particles in a 1:1 weight ratio were scatter coated onto the first fabric layer. A second fabric layer of 100% cotton plain weave (120 g) was placed on top of the first fabric layer so as to enclose the scattered coating mixture between the first and second fabric layers. The combined layers were hot laminated (150 °C) at with the application of 20 tonne equivalents of force (approx. 200,000 N).

The resultant fabric was analysed by optical microscopy. The functionalised cellulose active material particles are enclosed between the two cotton layers and the two layers bonded together by the adhesive. The resultant fabric was found to have an even distribution of functionalised cellulose active material particles, which was more evenly distributed than the fabric made according to Example 4. Further, the resultant fabric featured melted adhesive material granules adhering fibres of the first fabric layer to fibres of the second fabric layer, without encapsulating the functionalised cellulose active material particles. The functionalised cellulose active material particles were demonstrated to be capable of absorbing water. The adhesion between the layers was found to be strong. The adhesion between the layers was found to be stronger than that made according to example 4.

Example 6

Fabrics according to the invention were prepared using a roll-to-roll scattering and lamination process. A first fabric layer (BO cotton, woven, 106(±3) g/m2) was provided to a bulk fabric laminating machine. A mixture of particulate adhesive (Ecofix Hot-Melt Powder) and functionalised cellulose active material particles (250-500 pm particle size) were scatter coated onto the first fabric layer using a spreading unit. Then a second fabric layer (BCI cotton, woven, 106(±3) g/m2) was dropped onto the scatter coated first fabric layer. The resultant two-layer fabric was then fed into a lamination unit and rolled between rollers heated to 150 °C exerting a force of 9 tonne equivalents on the laminate material (approx. 90,000 N), see Table 1 below: Table 1: Fabrics made according to Example 6.

Adhesive: Mass of first fabric layer Mass of second fabric layer Mass of adhesive/ functionalised cellulose active material particles scatter coated functionalised cellulose active material particles (wt:wt) Sample 1 46:54 106 g/m2 106 g/m2 116 g/m2 Sample 2 60:40 106 g/m2 106 g/m2 71 g/m2 Sample 3 60:40 106 g/m2 106 g/m2 116 g/m2 Sample 4 80:20 106 g/m2 106 g/m2 Comparative Sample 5 100:0 106 g/m2 106 g/m2

Example 7

Materials prepared according to Example 6 were washed using a standard household washing machine.

Materials that were washed at 37°C as described above did not exhibit delamination of the fabric layers. Also, materials that were washed at 60°C as described above did not exhibit delamination of the fabric layers. Materials that were washed for 2 hours at 70°C as described above did not exhibit delamination of the fabric layers. It is noted that washing for 2 hours at 70 °C is believed to emulate clinical laundering processes.

Example 8

The antiviral activity of functionalised cellulose active material particles were evaluated by the protocol of ISO 18184:2019. Formulations comprising cellulose active material were tested for their viricidal activity against Influenza A virus or Human coronavirus NL63 at a contact time of 2 h relative to a reference control, following 15018184:2019. The formulations tested were (1) cellulose-containing microporous superabsorbent composition of Example 1, (2) silver metallised (AgNP) cellulose-containing microporous superabsorbent composition of Example 2(3) gold metallised (AuNP) cellulose-containing microporous superabsorbent composition of Example 2. The results are shown in Tables 2 and 3.

Table 2: Effect against Influenza A. A value of 2.0> My a.1.0 indicates good antiviral effect. A value of 3.0> My a 2.0 indicates very good antiviral effect. A value of My a 3.0 indicates excellent antiviral effect. *Affected cell susceptibility not valid for 15018184.

Nanocellulose form vs Influenza A [Hi Ni] % reduction My (antiviral Cytotoxic Affects cell ISO activity) sensitivity compliant Raw nanocellulose 99.9 3.17 N Y N* Water processed nanocellulose 99.9 3.63 N Y N* Silver metallised nanocellulose 99.9 3.93 N N Y Gold metallised nanocellulose 99.9 3.93 N N Y Table 3: Effect against Influenza A. A value of 2.0> My a1.0 indicates good antiviral effect. A value of 3.0> My a 2.0 indicates very good antiviral effect. A value of My a 3.0 indicates excellent antiviral effect.

Nanocellulose form vs Human % My (antiviral Cytotoxic Affects ISO Coronavirus [AIL63] reduction activity) cell compliant sensitivity Raw nanocellulose 99.9 3.53 N N V Water processed nanocellulose 99.9 3.16 N N Y Silver metallised nanocellulose 99.9 3.22 N N V Gold metallised nanocellulose 99.9 3.25 N N Y As can be seen from Tables all the nanocellulose materials exhibited good to excellent virucidal activity with a 99.9% reduction in viral titre (both influenza A and human coronavirus) at a contact time of 2 h relative to a reference control, following 15018184:2019 accredited procedures. Under these conditions all were ISO compliant except raw and washed nanocellulose samples since although they had potent antiviral activity, they were found to slightly influence growth of the type of cells used in the influenza assay.

Example 9

To establish that the antimicrobial cellulose-containing microporous superabsorbent composition do not exhibit loss of adhered silver nanoparticles on washing, the following test was conducted.

g of antimicrobial cellulose-containing microporous superabsorbent composition material was suspended in 4000 mL of water and 0.5 mL of non-biological detergent. The suspension was stirred for 2 hours at 70°C, filtered through filter paper with a pore size of 5-13 pm, washed 3 times with 500 mL of water, dried at 60°C. This cycle was repeated 5 times. The wash supernatant analysed by UV-Vis spectroscopy An antimicrobial cellulose-containing microporous superabsorbent composition comprising silver nanoparticles prepared according to Example 2 was tested. The material did not exhibit any loss of colour or intensity of colour, which is indicative that the silver nanoparticles were retained within the material. As can be seen in Figure 2, the absence of a peak in the 350-400 nm region in the supernatant confirms no significant loss of silver nanoparticles from the functionalised cellulose active material particles on washing.

Example 10

The viricidal activity of a simulated face mask material comprising a cotton and silver metallised (AgNP) cellulose microporous superabsorbent composition (prepared according to Example 10) was analysed by adding 100 pi phage Phi6 (DSMZ 21518) suspension (diluted to -1e7 cfu/ml) in phage buffer (7 g1-1 Na2HPO4, 3 g1-1 KH2PO4, 5 g1-1 NaCI, 1 mM Mg504-7(H20), 1 mM CaCl2) to 1 cm2 of the material for 2 hours at ambient conditions in a 2 ml microtube. Subsequently 1 ml of phage buffer was added, vortexed for 15 seconds and centrifuged for 3 minutes at 1000g.

The supernatant was removed and serially diluted in phage buffer. 100 pl aliquots were placed in 5 ml polypropylene tubes (VWR 211-0049) in triplicate. To each of these, 10 pl of 24 hr old Pseudomonas host cells (DSMZ 21482), which were grown statically at 28 °C in TSB broth (Sigma 22092) supplemented with filter sterilised MgSO4 (to 5 mM) was added and then incubated for a maximum of 20 minutes. Subsequently, 3-4 ml of 47°C molten TSB 0.5% agar supplemented with sterile Mg504 to 5 mM was added to each tube. Each tube was then poured on to the surface of petri plates containing 16 mls of solid 1.5% agar TSB plates supplemented with Mg504 to 5mM, before leaving to set for 20 minutes. Plates were then inverted and incubated at 25 °C for approximately 16 hrs or until visible plaques were observed. Triplicate plates were counted (where the dilution plated yielded between 30 and 300 visible plaques). Triplicate experiments were performed. The material was demonstrated to completely kill phage Phi6. Example 11 8 mm diameter nanocellulose disks were punched from dried thin films of C3PN nanocellulose material prepared from 2% slurry stocks mixed with equal volume of distilled water or 25 mM silver nitrate solution. 5 ml of slurry/water/silver solution mix were pooled on plastic to an area of 4.5 cm diameter and left to dry for 16 hours at 25 °C, followed by thrice rinsing in distilled water then allowed to dry. 201.11 of Dispersin B in phosphate buffered saline (PBS) at 0.3 mg/ml or PBS only was applied to the disks, incubated for 16 hours in a damp chamber and then rinsed 3 x in 5 ml PBS.

An agar plate (Figures 3-5) was coated with bacterial which express green fluorescent protein. The plate was allowed to develop a lawn of bacteria which express green fluorescent protein (24 hours). The following were deposited onto the lawn: (1) a disk of silver metallised (AgNP) cellulose-containing microporous superabsorbent composition was treated with 204 of water, which was placed onto the bacterial lawn(Figures 3-51100]); (2) a disk of silver metallised (AgNP) cellulose-containing microporous superabsorbent composition was treated with 204 of phosphate-buffered saline, which was placed onto the bacterial lawn (Figures 3-5 [101]); (3) a disk of silver metallised (AgNP) cellulose-containing microporous superabsorbent composition was treated with 204 of Dispersin (non-silver binding) solution, which was placed onto the bacterial lawn (Figures 3-5 [102]); (4) a disk of silver metallised (AgNP) cellulose-containing microporous superabsorbent composition was treated with 204 of Dispersin (silver binding) solution, which was placed onto the bacterial lawn (Figures 3-5 [103]); (5) a disk of cellulose-containing microporous superabsorbent composition was treated with 20 ttl_ of water, which was placed onto the bacterial lawn (Figures 3-5 [104]); (6) a disk of cellulose-containing microporous superabsorbent composition was treated with 204 of phosphate-buffered saline, which was placed onto the bacterial lawn (Figures 3-5 1105]); (7) a disk of cellulose-containing microporous superabsorbent composition was treated with 20 ti.L of Dispersin B (non-silver binding) solution, which was placed onto the bacterial lawn (Figures 3-5 [106]); (8) a disk of cellulose-containing microporous superabsorbent composition was treated with 20 p.L of Dispersin B (silver binding) solution, which was placed onto the bacterial lawn lawn (Figures 3-5 [107]); (9) 20 p.L of water was directly placed onto the bacterial lawn (Figures 3-5 [108]); (10)20 pl of phosphate-buffered saline was directly placed onto the bacterial lawn (Figures 3-5 [109]); (11)20 p.L of Dispersin B (non-silver binding) solution was directly placed onto the bacterial lawn (Figures 3-5 [110]); (12)20 p.L of Dispersin B (silver binding) solution was directly placed onto the bacterial lawn(Figures 3-5 [111]); and (13)20 p.L of bleach was directly placed onto the bacterial lawn (Figures 3-5 [112]); Alternatively the disks were applied to agar plates and the plates spread with bacterial culture (500 j.il of OD 600 nm 0.2) and again left for 24 hours at 25°C for Ps. syringae KP71 and 37 T for E. coli EC5025. After 24 hours contact, the plates were imaged under white light, ultra-violet (UV) light with an orange filter, under UV with the disks of material removed, the disks themselves viewed under UV.

GFP expressing Ps. syringae KP71 and E. coli EC5025 were used as the bacterial test materials. Deposited materials 1-8 were shown to possess significant antibacterial activity. The results are shown in Figures 3-5.

Figure 3 shows the locations on the plate of each of the 13 deposited materials, which is maintained in the experimental results of Figures 4 and 5. Figure 3 can be used as a general reference for the locations of the deposited materials in Figures 4 and 5. For clarity, reference numbers [100] -[112] and [200] are only indicated on Figure 4A and 5A, but can be understood to be also present in the other images of Figures 4 and 5 on the same general positions.

Figures 4A, 4E, 5A and 5E are white light images taken from treated agar plates. Figures 4B, 4C, 4D, 4F, 4G, 4H, 5B, 5C, 5D, 5F, 5G and 5H are UV light orange filtered images taken from treated agar plates. Increased pixel intensity (i.e. brighter image) in the UV light images indicates an increased level of GFP, which correlates with a higher number of bacteria. Figure 4 shows results from the experiments using GFP expressing E. coli EC5025, while figures shows results from the experiments using GFP expressing Ps. syringae KP71. Figures 4A-D and SA-D show the experiments as detailed above where the bacteria were allowed to develop a lawn for 24 h after which the materials and disks were deposited. Figures 4E-H and 5E-H show the experiments as detailed above where the materials and disks were deposited prior to applying the bacteria. Figures 4B, 4F, 5B and 5F show the plates with the disks. Figures 4C, 4G, 5C and 5G show the plates with the disks removed. Figures 4D, 4H, 5D and 5H show the filter disks after removal from the plates.

As can be clearly seen from the Figures, the silver metallised (AgNP) cellulose-containing microporous superabsorbent composition displayed strong antibacterial properties, whereas the bleach, Dispersin B and unfunctionalized cellulose-containing microporous superabsorbent composition displayed modest antibacterial properties. This is evident when comparing the lower pixel intensity (i.e. lower number of bacteria) of [100], [101], [102] and [103] of Figures 4B, 4C, 4D, 4F, 4G, 4H, 5B, 5C, 5D, 5F, 5G and 5H to the higher pixel intensity of the other treated areas. The silver metallised (AgNP) cellulose-containing microporous superabsorbent composition reduced both the number of bacteria on the plates (Figures 4C, 4G, 5C and 5G) and had a reduced number of bacteria on the disks (Figures 4D, 4H, 5D and 5H) when compared to controls and the non-silver metallised cellulose-containing microporous superabsorbent composition.

Moreover, there was a strong, unexpected synergistic antibacterial function of the combination of silver metallised (AgNP) cellulose-containing microporous superabsorbent composition treated with 204 of Dispersin B (both silver binding and non-silver binding) solution (see [102] and [103] of Figures 4D, 4H, 5D and 5H), which was strongest for the silver binding Dispersin B solution.

Example 12

A simulated face mask material comprising cotton and silver metallised (AgNP) cellulose-containing microporous super absorbent composition was made according to the following process: A BO cotton woven base-sheet (single layer weight of 106 ± 3% g/m2) was provided. A Muratex spreading and pressing machine was used to scatter coat the base-sheet with 63 g/m2 of a mixture. The mixture was solely composed of silver metallised (AgNP) cellulose-containing microporous super absorbent composition prepared according to Example 2 [54 wt.Y0] and adhesive powder particles (Ecofix Hot-Melt Powder, a hot melt aliphatic aromatic copolyester) [46 wt.%]. The scatter coating was realized with a hollow needle that rapidly moved across the cotton base-sheet to provide an even distribution of the powder mixture over the base-sheet. A BC! cotton top-sheet (106 ± 3% g/m2) was then laid on to the base-sheet to enclose the powder between the sheets. The sheets were then passed though hot rollers twice (9 tonnes of pressure equivalent), where the hot rollers applied heat and pressure to melt the adhesive and adhere the base-sheet to the top-sheet around the silver metallised (AgNP) cellulose-containing microporous super absorbent composition particles.

Air permeability values were obtained for (1) a fabric manufactured as described above, (2) a commercially available double-layer, dense cotton fabric and (3) a commercially available blue 3-ply polyethylene, disposable face mask. The commercially available double-layer, dense cotton fabric was manufactured by Halley Stevensons, is made of two layers of BO cotton woven sheet (single layer weight of 106 ± 3% g/m2, double layer weight 212 g/m2), and is used in the manufacture of medical garments. The commercially available surgical face mask comprised a standard spunbondend layer. The fabric manufactured according to the method of Example 6 exhibited an air permeability of 496 mm/s at a pressure of 200 Pa over a test area of 20 cm2. The commercially available double-layer, dense cotton fabric exhibited an air permeability of 74 mm/s at a pressure of 200 Pa over a test area of 20 cm2. The commercially available surgical face mask exhibited an air permeability of 379 mm/s at a pressure of 200 Pa over a test area of 20 cm2.

The air permeability values for fabric manufactured according to the method of Example 6 were demonstrated to be superior to those of the commercially available medical mask and double-layer, dense cotton fabric.

Example 13

The cellulose active material particles of Example 1 was deposited onto a moving conveyor belt to form a loose bed of 2-5 mm depth. The loose bed on the conveyor belt was run under a spraying unit, which sprayed the loose bed cellulose-containing microporous superabsorbent composition with 2 weight equivalents of a 5 mM aqueous solution of AgNO3 at 25 °C. The cellulose-containing microporous superabsorbent composition rapidly absorbed the 5 mM aqueous solution of AgNO3 to afford a loose, dampened bed of bed cellulose-containing microporous composition which has absorbed 2 weight equivalents of a 5 mM aqueous solution of AgNO3. This loose, dampened bed on the conveyor belt was run under a UV-light source and irradiated with UV light for 30 seconds. The resultant UV-light-irradiated loose bed of silver treated cellulose-containing microporous composition was then dried. The resultant material was analysed and found to comprise silver nanoparticles.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMS1. An antimicrobial fabric comprising: i. a first fabric layer; ii. an adhesive layer comprising adhesive material and functionalised cellulose active material particles; and a second fabric layer, wherein the adhesive layer is adhered to the first fabric layer and to the second fabric layer.
2. The antimicrobial fabric according to claim 1 wherein the first and/or second fabric comprise a non-woven layer, preferably wherein the non-woven layer is selected from spun-bonded polymer.
3. The antimicrobial fabric according to claim 1 wherein the first and/or second fabric layer comprises a woven layer, preferably wherein the first and/or second fabric layer is a woven fabric selected from buckram fabric, cambric fabric, casement fabric, cheese cloth, chiffon fabric, chintz fabric, corduroy fabric, crepe fabric, denim fabric, drill fabric, flannel fabric, garbadine fabric, georgette fabric, Kashmir silk fabric, Khadi fabric, lawn fabric, mulmul fabric, muslin fabric, poplin fabric, sheeting fabric, taffeta fabric, tissue fabric, aertex fabric, Madras muslin net fabric, Aida cloth fabric, velvet fabric, mousseline fabric, organdie fabric, organza fabric or leno fabric.
4. The antimicrobial fabric according to any one of claims 1 to 3, wherein at least the first fabric layer is water repellent, but at least in part gas transmissive.
5. The antimicrobial fabric according to any one of claims 1 to 4, wherein the adhesive is a thermoplastic adhesive, preferably wherein the thermoplastic adhesive is selected from polymeric adhesives comprising ethylene-vinyl acetate copolymers, modified ethylene acetate vinyl copolymers, polyolefins, preferably polyethylene or polypropylene; polyamides, polyesters, polyvinyl chloride polymers or derivatives thereof, high melting waxes, or mixtures thereof.
6. The antimicrobial fabric according to any one of claims 1-5, wherein the functionalised c is functionalised with antimicrobial activity.
7. The antimicrobial fabric according to claim 6, wherein the antimicrobial activity is at least in part derived from antimicrobially active nanoparticles, preferably wherein the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), gold nanoparticles [AuNPs] or copper nanoparticles (CuNPs), more preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs), or copper nanoparticles (CuNPs), most preferably, the antimicrobial nanoparticles are selected from silver nanoparticles (AgNPs).
8. The antimicrobial fabric according to any one of claims 1-7, wherein the functionalised cellulose active material is functionalised with antimicrobial peptides and/or proteins, preferably wherein the antimicrobial peptides or proteins comprise peptides or proteins having an amino acid sequence selected from the group consisting of AU1, AU2, AU3, 1037, LF1-II, KR12, lactoferrampin, FK-16 and Dispersin B (SEQ ID NOs 1XX to XX9) , most preferably Dispersin B (SEQ ID NO 9).
9. The antimicrobial fabric according to any one of claims 1-8, wherein the adhesive layer comprises adhesive material and functionalised cellulose active material particles in a weight ratio of from 20:1 to 3:1, more preferably from 16:1 to 4:1, more preferably still from 12:1 to 6:1, most preferably from 10:1 to 8:1.
10. The antimicrobial fabric according to any one of claims 1-9, wherein the adhesive layer has a single layer weight of from 10 g/m2to 100 g/m2, preferably of from 20 g/m2 to 80 g/m2, more preferably still of from 25 g/m2 to 75 g/m2, most preferably of from SO g/m2 to 65 g/m2.
11. A method of manufacturing the antimicrobial fabric according to claims 1-10 comprising the following steps: i. Providing a first fabric layer; ii. Depositing an adhesive and particulate functionalised cellulose active material onto the first fabric layer; iii. Depositing a second fabric layer onto the coated surface of the first fabric layer; and iv. Heating the laminate under pressure to adhere the first fabric layer to the second fabric layer.
12. The method of claim 11, wherein the step of depositing a blend comprises a scatter coating deposition.
13. The method of claims 11 or 12, wherein the heating step is performed with application of a force, preferably applied by a roller or heated roller, wherein the force is from 9800 N to 490000 N, more preferably 49000 N to 245000 N, yet more preferably 78400 N to 215600 N and most preferably 88200 N to 196000 N.
14. The method of any one of claims 11-13, wherein the method is a roll-to-roll method, preferably a roll-to-roll process wherein the heating step is a localised heating step.
15. Use of the antimicrobial fabric according to any one of claims 11 to 14 in the manufacture of personal protective equipment.
16. An antimicrobial face mask comprising the antimicrobial fabric according to any one of claims 1 to 15.
17. The antimicrobial face mask according to claim 16 for use in prophylactic treatment or avoidance of contagion.
18. The antimicrobial face mask according to claim 16 for use in prophylactic treatment of airborne diseases, preferably for use in the prophylactic treatment of an airborne disease selected from coronavirus, the common cold, influenza, chickenpox, mumps, measles, whooping cough, tuberculosis, diphtheria, tuberculosis, more preferably for use in the prophylactic treatment of an airborne disease selected from a corona virus and influenza virus, most preferably for use in the prophylactic treatment of a coronavirus.
19. Personal protective equipment comprising antimicrobial fabric according to any one of claims 1-10, preferably wherein the personal protective equipment is selected from a face mask, a surgical mask, a respirator and a gown, more preferably wherein the personal protective equipment is selected from a face mask, a surgical mask and a respirator, most preferably wherein the personal protective equipment is a face mask.
20. Use of the antimicrobial fabric according to any one of claims 1-12 in the manufacture of sports clothing, outdoor clothing, protective clothing, or other garments.