Cleaning method

Abstract

The invention provides a method and formulation for cleaning a soiled substrate, the method comprising the treatment of the moistened substrate with a formulation comprising a multiplicity of polymeric particles, wherein the polymeric particles comprise at least one antimicrobial agent. Preferably, the substrate is wetted so as to achieve a substrate to water ratio of between 1:0.1 to 1:5 w/w. Optionally, the formulation additionally comprises at least one additional cleaning agent, and in this embodiment, it is preferred that the polymeric particles are mixed with the at least one additional cleaning agent. Preferably, the additional cleaning material comprises a surfactant, which most preferably has detergent properties. Most preferably, the substrate comprises a textile fiber. Typically, the polymeric particles comprise particles of polyester or nylon, most preferably in the form of beads. The results obtained are very line with those observed when carrying out conventional aqueous cleaning processes and the method provides the significant advantage that the use of antimicrobial agents in or on the polymer bead greatly improves the overall hygiene in the washing machine by preventing mold and bacterial growth on the polymer particle surfaces, particularly at low temperatures.

Claims

1. A method for cleaning a soiled substrate, said method comprising the treatment of a moistened soiled substrate with a formulation comprising a multiplicity of polymeric particles, wherein said polymeric particles comprise at least one antimicrobial agent, where said soiled substrate comprises leather or a textile fibre or fabric, and subsequently separating the polymeric particles from the substrate and recovering the polymeric particles in order to allow for re-use, wherein said antimicrobial agent is introduced into said polymer particles during extrusion of said polymer.

2. The method as claimed in claim 1, wherein said textile fibre or fabric is a natural or synthetic fibre or fabric, wherein said natural or synthetic fibre or fabric comprises cotton, nylon 6,6 or a polyester.

3. The method as claimed in claim 1, wherein said soiled substrate is wetted by contact with mains or tap water so as to achieve a substrate to water ratio of between 1:0.1 to 1:5 w/w.

4. The method as claimed in claim 1, wherein the ratio of said particles to the soiled substrate is in the range of from 0.1:1 to 10:1 w/w.

5. The method as claimed in claim 1, wherein said method comprises a batchwise process or continuous process and said treatment is carried out at a temperature of between 5 and 35 C. and/or for a duration of between 5 and 45 minutes.

6. The method as claimed in claim 1, wherein said antimicrobial agent comprises a solid chlorophenol derivative or a silver-containing material.

7. The method as claimed in claim 6, wherein said solid chlorophenol derivative comprises 5-chloro-2-(2,4-dichlorophenoxy)phenol or its derivatives.

8. The method as claimed in claim 6, wherein said silver-containing material comprises a silver-containing zeolite material.

9. The method as claimed in claim 1, wherein said antimicrobial agent is added to said polymer at a level of 0.1-5.0% (w/w).

10. The method as claimed in claim 1, wherein said formulation further comprises at least one additional cleaning agent.

11. The method as claimed in claim 10, wherein said at least one additional cleaning agent comprises at least one surfactant and said surfactant comprises at least one anionic, non-ionic, cationic, ampholytic, zwitterionic and/or semi-polar non-ionic surfactant.

12. The method as claimed in claim 11, wherein said at least one surfactant comprises at least one surfactant having detergent properties and said at least one additional cleaning agent comprises at least one detergent formulation.

13. The method as claimed in claim 11, wherein said at least one additional cleaning agent also comprises at least one enzyme and/or bleach.

14. The method as claimed in claim 11, wherein said at least one additional cleaning agent is mixed with said polymeric particles or is coated with said at least one additional cleaning agent.

15. The method as claimed in claim 12, wherein said detergent formulation additionally comprises at least one additive selected from anti-redeposition additives, optical brighteners, perfumes, softeners, builders, chelating agents, dye transfer inhibiting agents, dispersants, enzyme stabilizers, catalytic materials, bleach activators, polymeric dispersing agents, clay soil removal agents, suds suppressors, dyes, structure elasticizing agents, fabric softeners, starches, earners, hydrotropes, processing aids and/or pigments.

16. The method as claimed in claim 1, wherein said polymeric particles comprise polyalkenes, polyesters, polyamides or polyurethanes, or their copolymers, wherein said polyamide particles comprise nylon beads and wherein said nylon beads comprises Nylon 6,6 homopolymer having a molecular weight in the region of from 5000 to 30000 Daltons.

17. The method as claimed in claim 1, wherein said polymeric particles are in the shape of spheres, cubes or cylinders, and said particles are solid or hollow, wherein said cylindrically shaped particles optionally have an average particle diameter in the region of from 1.0 to 6.0 mm and the length of said particles is in the range of from 1.0 to 5.0 mm.

18. The method as claimed in claim 1, wherein said particles have an average mass in the region of from 1 to 50 mg.

19. The method as claimed in claim 1, wherein said polymeric particles comprise foamed or unfoamed polymeric materials and said polymers are either linear or crosslinked.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

(2) FIGS. 1(a) and (b) show an apparatus suitable for use in the performance of the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(3) As previously noted, the antimicrobial agent is most conveniently introduced into the polymer particles during extrusion of said polymer and is then added in a suitable amount to the molten polymer prior to extrusion. Particularly suitable agents include solid chlorophenol derivatives, such as 5-chloro-2-(2,4-dichlorophenoxy)phenol, which is commercially available as Triclosan or Microban, or its derivatives, and silver-containing materials, including products from the Bio-Gate, Irgaguard or HyGate ranges including, for example, Bio-Gate BG-Tec Plus, Irgaguard B 5000, Irgaguard B 7000, HyGate 4000 and HyGate 9000. Preferably, said antimicrobial agent is added to said polymer at a level of 0.1-5.0%, (w/w), most preferably 0.5-2.5% (w/w), especially preferably 1.5-2.0% (w/w).

(4) In alternative embodiments, the polymer particles may be coated with the antimicrobial agent after extrusion in which case the particles are suitably placed in a container with an appropriate amount of the antimicrobial agent, and the preferably sealed container is agitated for, typically, 15-30 minutes at temperatures at or just above ambient temperature. The coated particles are then removed from the container and are ready for use in cleaning processes.

(5) In a typical operation of a cleaning cycle according to the method of the invention, soiled garments are first placed into a rotatably mounted cylindrical cage of a cleaning apparatus according to the method described in WO-A-2011/098815. Such an apparatus is illustrated in FIGS. 1(a) and 1(b), wherein there is seen an apparatus comprising housing means (1) having a first upper chamber having mounted therein a rotatably mounted cylindrical cage in the form of drum (2) (perforations not shown) and a second lower chamber comprising sump (3) located beneath said cylindrical cage. The apparatus additionally comprises, as first recirculation means, bead and water riser pipe (4) which feeds into separating means comprising a bead separation vessel (5), including filter material, typically in the form of a wire mesh, and a bead release gate valve which feeds into feeder means comprising bead delivery tube (6) mounted in cage entry (7). The first recirculation means is driven by pumping means comprising bead pump (8). Additional recirculation means comprises return water pipe (9), which allows water to return from the bead separation vessel (5) to the sump (3) under the influence of gravity. The apparatus also comprises access means shown as loading door (10), though which material for cleaning may be loaded into drum (2). The main motor (20) of the apparatus, responsible for driving the drum (2), is also depicted.

(6) Following loading of the soiled garments into said apparatus, the polymeric particles and the necessary amount of water, together with any required additional cleaning agent, are added to said rotatably mounted cylindrical cage (2). Optionally, said materials are introduced via the first recirculation means (4) into the cylindrical cage (2), which is located in a first chamber of said apparatus. Alternatively, said polymeric particles may, for example, be pre-mixed with water and added via the separating means (5) located adjacent said cylindrical cage (2).

(7) During the course of agitation by rotation of the cage (2), the fluids and a quantity of the polymeric particles exit through perforations in the cage (2) and into the second chamber (3) of the apparatus. Thereafter, the polymeric particles may be recirculated via the first recirculation means (4) such that they are transferred to the separating means (5), from which they are returned, in a manner controlled by control means, to the cylindrical cage (2) for continuation of the washing operation. This process of continuous circulation of the polymeric particles continues throughout the washing operation until cleaning is completed.

(8) Thus, the polymeric particles which exit through the perforations in the walls of said rotatably mounted cylindrical cage (2) and into said second chamber (3) are recirculated and reintroduced through said separation means (5) and, by operation of control means, through the feeder means (6), back into said cage (2), thereby to continue the cleaning operation.

(9) Typically, a wash cycle according the method of the present invention comprises the steps of: (a) introducing polymeric particles, additional cleaning agent and water into a second chamber of a cleaning apparatus of the type described in WO-A-2011/098815; (b) agitating said polymeric particles, additional cleaning agent and water; (c) loading at least one soiled substrate into the rotatably mounted cylindrical cage of said apparatus via access means; (d) closing the access means so as to provide a substantially sealed system; (e) introducing said polymeric particles, additional cleaning agent and water into said rotatably mounted cylindrical cage; (f) operating the apparatus for a wash cycle, wherein said rotatably mounted cylindrical cage is caused to rotate and wherein fluids and polymeric particles are caused to fall through perforations in said rotatably mounted cylindrical cage into said second chamber in a controlled manner; (g) operating pumping means so as to transfer fresh polymeric particles and recycle used polymeric particles to separating means; (h) operating control means so as to add said fresh and recycled polymeric particles to said rotatably mounted cylindrical cage in a controlled manner; and (i) continuing with steps (f), (g) and (h) as required to effect cleaning of the soiled garments.

(10) Optionally, said polymeric particles, additional cleaning agent and water may be introduced into said rotatably mounted cylindrical cage via recirculating means. More preferably, however, said polymeric particles, additional cleaning agent and water are introduced into said rotatably mounted cylindrical cage via dosing means such as, for example, a fixedly mounted nozzle. Most conveniently, said nozzle may be fixedly mounted on said access means.

(11) Additional cleaning agents are advantageously employed in said method, as further discussed below. Said additional cleaning agents may be added to the second chamber of said apparatus with said polymeric particles and introduced, via the first recirculation means, into the cylindrical cage. Alternatively, an additional cleaning agent is pre-mixed with water and added to said cylindrical cage via the separating means during step (e). More preferably, however, said additional cleaning agents are added to said cylindrical cage via said dosing means. The method of the invention facilitates the use of reduced quantities of said additional cleaning agents.

(12) In preferred embodiments of the invention, said additional cleaning agents may be added to said cylindrical cage in multiple dosing steps during the cleaning operation, rather than in a single dosing step.

(13) Preferably, pumping of said fresh and recycled polymeric particles proceeds at a rate sufficient to maintain approximately the same level of particles in said rotatably mounted cylindrical cage throughout the cleaning operation, and to ensure that the ratio of particles to soiled garments stays substantially constant until the wash cycle has been completed.

(14) On completion of the wash cycle, feeding of polymeric particles into the rotatably mounted cylindrical cage ceases and the speed of rotation of the cage is gradually increased in order to effect a measure of drying of the cleaned substrate. Some polymeric particles are removed at this stage. Typically, the cage is rotated at a rotation speed of between 100 and 800 rpm in order to achieve drying; for a 98 cm diameter cage, a suitable speed of rotation would be around 300 rpm. Subsequently, rotation speed is reduced and returned to the speed of the wash cycle, so as to allow for final removal of the polymeric particles. After separation, the polymeric particles are recovered in order to allow for re-use in subsequent washes.

(15) Optionally, following initial drying at high rpm, said method may additionally comprise a rinsing operation, wherein additional water may be added to said rotatably mounted cylindrical cage in order to effect complete removal of any additional cleaning agent employed in the cleaning operation. Water may be added to said cylindrical cage via said separating means, by said dosing means, or by overfilling the second chamber of said apparatus with water such that it enters the first chamber and thereby enters into said rotatably mounted cylindrical cage. Following rotation at the same speed as during the wash cycle, water is removed from said cage by allowing the water level to fall, as appropriate, and again increasing the speed of rotation to, typically, 100-800 rpm in order to achieve a measure of drying of the substrate; a speed of rotation of around 300 rpm would, once again, be appropriate for a 98 cm diameter cage. Said rinsing and drying cycles may be repeated as often as desired.

(16) Optionally, said rinse cycle may be used for the purposes of substrate treatment, involving the addition of treatment agents such as anti-redeposition additives, optical brighteners, perfumes, softeners and starch to the rinse water.

(17) Said polymeric particles are preferably subjected to a cleaning operation in said second chamber by sluicing said chamber with clean water in the presence or absence of a cleaning agent, which may be selected from at least one of surfactants, enzymes and bleaches. Alternatively, cleaning of the polymeric particles may be achieved as a separate stage in said rotatably mounted cylindrical cage. After cleaning, the polymeric particles are recovered such that they are available for use in subsequent washes.

(18) Generally, any remaining polymeric particles on said garments may be easily removed by shaking the garments. If necessary, however, further remaining polymeric particles may be removed by suction means, preferably comprising a vacuum wand.

(19) The method of the invention is principally applied to the cleaning of substrates comprising textile fibres and fabrics, and has been shown to be particularly successful in achieving efficient cleaning of textile fabrics which may, for example, comprise either natural materials, such as cotton, or man-made and synthetic textile materials, for example nylon 6,6, polyester, cellulose acetate, or fibre blends thereof.

(20) The volume of wash water added to the system is calculated so as to achieve a fabric to wash water ratio which is preferably between 1:0.1 and 1:5 w/w; more preferably, the ratio is between 1:0.2 and 1:2, with particularly favourable results having been achieved at ratios such as 1:0.2, 1:1, 1:1.2 and 1:2. Most conveniently, the required amount of water is introduced into the rotatably mounted cylindrical cage of the apparatus after loading of the soiled substrate into said cage. An additional amount of water will migrate into the cage during the circulation of the polymeric particles, but the amount of water carry over is minimised by the action of the separating means.

(21) As previously stated, preferred embodiments of the method of the invention envisage the cleaning of soiled textile fibres or fabrics by treatment of the moistened fibres or fabrics with a formulation which include a multiplicity of polymeric particles and further comprise at least one additional cleaning agent. Said at least one additional cleaning agent preferably comprises at least one detergent composition.

(22) The principal components of the detergent composition comprise cleaning components and post-treatment components. Typically, the cleaning components comprise surfactants, enzymes and bleach, whilst the post-treatment components include, for example, anti-redeposition additives, optical brighteners, perfumes, softeners and starch.

(23) However, the detergent composition may optionally include one or more other additives such as, for example builders, chelating agents, dye transfer inhibiting agents, dispersants, enzyme stabilizers, catalytic materials, bleach activators, polymeric dispersing agents, clay soil removal agents, suds suppressors, dyes, structure elasticizing agents, fabric softeners, starches, carriers, hydrotropes, processing aids and/or pigments.

(24) Examples of suitable surfactants may be selected from non-ionic and/or anionic and/or cationic surfactants and/or ampholytic and/or zwitterionic and/or semi-polar nonionic surfactants. The surfactant may be present at a level of from about 0.1% to about 99.9% by weight of the cleaning composition, but is usually present from about 1% to about 80%, more typically from about 5% to about 35%, or from about 5% to 30% by weight of the cleaning compositions.

(25) The detergent composition may include one or more detergent enzymes which provide cleaning performance and/or fabric care benefits. Examples of suitable enzymes include, but are not limited to, hemicellulases, peroxidases, proteases, other cellulases, other xylanases, lipases, phospholipases, esterases, cutinases, pectinases, keratanases, reductases, oxidases, phenoloxidases, lipoxygenases, ligninases, pullulanases, tannases, pentosanases, malanases, [beta]-glucanases, arabinosidases, hyaluronidase, chondroitinase, laccase, and amylases, or mixtures thereof. A typical combination may comprise a mixture of enzymes such as protease, lipase, cutinase and/or cellulase in conjunction with amylase.

(26) Optionally, enzyme stabilisers may also be included amongst the cleaning components. In this regard, enzymes for use in detergents may be stabilised by various techniques, for example by the incorporation of water-soluble sources of calcium and/or magnesium ions in the compositions.

(27) The detergent composition may include one or more bleach compounds and associated activators. Examples of such bleach compounds include, but are not limited to, peroxygen compounds, including hydrogen peroxide, inorganic peroxy salts, such as perborate, percarbonate, perphosphate, persilicate, and monopersulphate salts (e.g. sodium perborate tetrahydrate and sodium percarbonate), and organic peroxy acids such as peracetic acid, monoperoxyphthalic acid, diperoxydodecanedioic acid, N,N-terephthaloyl-di(6-aminoperoxycaproic acid), N,N-phthaloylaminoperoxycaproic acid and amidoperoxyacid. Bleach activators include, but are not limited to, carboxylic acid esters such as tetraacetylethylenediamine and sodium nonanoyloxybenzene sulfonate.

(28) Suitable builders may be included in the formulations and these include, but are not limited to, the alkali metal, ammonium and alkanolammonium salts of polyphosphates, alkali metal silicates, alkaline earth and alkali metal carbonates, aluminosilicates, polycarboxylate compounds, ether hydroxypolycarboxylates, copolymers of maleic anhydride with ethylene or vinyl methyl ether, 1,3,5-trihydroxybenzene-2,4,6-trisulphonic acid, and carboxymethyl-oxysuccinic acid, various alkali metal, ammonium and substituted ammonium salts of polyacetic acids such as ethylenediamine tetraacetic acid and nitrilotriacetic acid, as well as polycarboxylates such as mellitic acid, succinic acid, oxydisuccinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic acid, carboxymethyloxysuccinic acid, and soluble salts thereof.

(29) The detergent composition may also optionally contain one or more copper, iron and/or manganese chelating agents and/or one or more dye transfer inhibiting agents. Suitable polymeric dye transfer inhibiting agents include, but are not limited to, polyvinylpyrrolidone polymers, polyamine N-oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, polyvinyloxazolidones and polyvinylimidazoles or mixtures thereof.

(30) Optionally, the detergent formulation can also contain dispersants. Suitable water-soluble organic materials are the homo- or co-polymeric acids or their salts, in which the polycarboxylic acid may comprise at least two carboxyl radicals separated from each other by not more than two carbon atoms.

(31) Suitable anti-redeposition additives are physico-chemical in their action and include, for example, materials such as polyethylene glycol, polyacrylates and carboxy methyl cellulose.

(32) Optionally, the detergent composition may also contain perfumes. Suitable perfumes are generally multi-component organic chemical formulations, a suitable example of which is Amour Japonais supplied by Symrise AG.

(33) Appropriate optical brighteners fall into several organic chemical classes, of which the most popular are stilbene derivatives, whilst other suitable classes include benzoxazoles, benzimidazoles, 1,3-diphenyl-2-pyrazolines, coumarins, 1,3,5-triazin-2-yls and naphthalimides. Examples of such compounds include, but are not limited to, 4,4-bis[[6-anilino-4(methylamino)-1,3,5-triazin-2-yl]amino]stilbene-2,2-disulfonic acid, 4,4-bis[[6-anilino-4-[(2-hydroxyethyl)methylamino]-1,3,5-triazin-2-yl]amino]stilbene-2,2-disulphonic acid, disodium salt, 4,4-Bis[[2-anilino-4-[bis(2-hydroxyethyl)amino]-1,3,5-triazin-6-yl]amino]stilbene-2,2-disulfonic acid, disodium salt, 4,4-bis[(4,6-dianilino-1,3,5-triazin-2-yl)amino]stilbene-2,2-disulphonic acid, disodium salt, 7-diethylamino-4-methylcoumarin, 4,4-Bis[(2-anilino-4-morpholino-1,3,5-triazin-6-yl)amino]-2,2-stilbenedisulfonic acid, disodium salt, and 2,5-bis(benzoxazol-2-yl)thiophene.

(34) Said agents may be used either alone or in any desired combination and may be added to the cleaning system at appropriate stages during the cleaning cycle in order to maximise their effects.

(35) The method of the present invention may be used for either small or large scale batchwise or continuous processes and finds application in both domestic and industrial cleaning processes.

(36) As previously noted, the method of the invention finds particular application in the cleaning of textile fibres and fabrics. The conditions employed in such a cleaning system do, however, allow the use of significantly reduced temperatures from those which typically apply to the conventional wet cleaning of textile fibres and fabrics and, as a consequence, offer significant environmental and economic benefits. Thus, typical procedures and conditions for the wash cycle require that fibres and fabrics are generally treated according to the method of the invention at, for example, temperatures of between 5 and 35 C. for a duration of between 5 and 45 minutes, optimally in a substantially sealed system. Thereafter, additional time is required for the completion of the rinsing and bead separation stages of the overall process, so that the total duration of the entire cycle is typically in the region of 1 hour.

(37) It is at these lower wash temperatures that the efficacy of the presently claimed invention is greatest. The inventors have sought, by addition of an antimicrobial agent to the polymeric particles used, to provide a process in which lower levels of mould and bacterial growth occur in the washing machine at all times. The introduction of the antimicrobial agent in this way, overcomes the drawbacks associated with single use addition into the wash water (i.e. fabric damage, expense and effluent treatment considerations), and its action is continuous over the lifetime of the polymeric particles, as said particles are re-used many times in subsequent washes, as is common practice with this technology.

(38) The invention will now be further illustrated, though without in any way limiting the scope thereof, by reference to the following examples and associated illustrations.

EXAMPLE

(39) Approximately 80 kg of nylon 6,6 beads were supplied by Rhodia Operations, Aubervilliers, Francegrade 24FE3. This material was divided into individual samples of approximately 20 kg, each of which was then dried for 3% hours at 80 C. in a desiccator. The polymer beads and the appropriate amounts of a silver zeolite antimicrobial agent (Bio Gate BG-Tec Plus) when used, were intimately mixed by shaking them together in a sealed container, prior to extrusion using a Rondol 21 mm diameter twin screw extruder at Smithers-RAPRA, Shawbury, UK. The four samples of polymer beads produced contained 0% (as a control, comparative example), and 1.0, 1.5 and 2.0% w/w levels of the Bio Gate BG-Tec Plus respectively. The twin screw extruder was operated with a screw speed of 400 rpm, and with 8 sequential temperature settings down the barrel, namely: zone 1 @ 240 C., zone 2 @ 250 C., zone 3 @ 260 C., zone 4 @ 265 C., zone 5 @ 265 C., zone 6 @ 265 C., and zone 7 @ 265 C. The die plate (zone 8) was also maintained at 265 C. The extruded lace was then passed through a water bath to cool and form a continuous solid strand, before being cut to form polymer beads of approximate dimensions 4.01.71.7 mm.

(40) In order to test the antimicrobial efficiency of these beads, 25 g aliquots of each bead sample were inoculated with 6 ml of either pseudomonas aeruginosa (pa) at approximately 3.110.sup.3 cfu/ml (colony forming units/milliliter), or aspergillus brasiliensis (ab) at approximately 1.410.sup.3 cfu/ml. The inoculated beads were then stored at (311) C. for the duration of the study, and at various time points (t), samples of the beads representing 1 ml of the inoculum (i.e. 5.17 g of beads/inoculum mixture) were removed to 9 ml of diluent and shaken vigorously. The resulting suspensions were tested using a standard plate count method. Incubation was for 5 days at (311) C. for the pa based suspensions in tryptone soya agar growth medium, and for 5 days at (241) C. for the ab based suspensions in sabouraud dextrose agar growth medium. The results are shown in Table 1.

(41) TABLE-US-00001 TABLE 1 pa and ab cfu/ml Results for the Inoculated Bead Samples Count (cfu/ml) Count (cfu/ml) Count (cfu/ml) Count (cfu/ml) Count (cfu/ml) Bead Sample at t = 0 at t = 24 hours at t = 4 days at t = 7 days at t = 14 days 24FE3 control pa = 3.1 10.sup.3 pa = >10.sup.6 pa = >10.sup.6 pa = >10.sup.6 pa = >10.sup.6 ab = 1.4 10.sup.3 ab = 1.5 10.sup.3 ab = Not ab = 2.1 10.sup.4 ab = 1.8 10.sup.4 Measured 24FE3 + 1.0% pa = 3.1 10.sup.3 pa = 1.3 10.sup.5 pa = >10.sup.6 pa = >10.sup.6 pa = >10.sup.6 w/w BG-Tec ab = 1.4 10.sup.3 ab = 1.5 10.sup.3 ab = Not ab = 1.4 10.sup.2 ab = 10 Plus Measured 24FE3 + 1.5% pa = 3.1 10.sup.3 pa = 2.1 10.sup.5 pa = 5.3 10.sup.5 pa = 3.6 10.sup.5 pa = >10.sup.6 w/w BG-Tec ab = 1.4 10.sup.3 ab = 1.3 10.sup.3 ab = Not ab = 1.6 10.sup.2 ab = <10 Plus Measured 24FE3 + 2.0% pa = 3.1 10.sup.3 pa = <10 pa = <10 pa = <10 pa = <10 w/w BG-Tec ab = 1.4 10.sup.3 ab = 1 10.sup.3 ab = Not ab = 1.5 10.sup.2 ab = <10 Plus Measured

(42) As can be seen from Table 1, there is a pronounced antimicrobial effect from the 24FE3 beads extruded with the 2.0% w/w BG-Tec Plus antimicrobial agent. This has resulted in suppression of mould and bacterial growth in repeated use washing with these antimicrobial beads in apparatus as described in WO-A-2011/098815.

(43) 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.

(44) 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.

(45) 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.