The present invention relates to antimicrobial coating compositions and methods for providing an antimicrobial coating. In particular the invention relates to a methods and compositions for providing a coating to combat contamination due to handling of an object.

A significant problem exists due to exposure to microbes as a result of contact with an infected surface. Many handheld items which are passed from person to person can become infected with microbes. An infected person may have microbes on their hand which are spread to an object carried by that person. A different person who subsequently picks up the object is then infected with the microbes from the object even if there was no direct hand-to-hand contact with the initially infected person. Cross-contamination of this type represents a serious public health issue. In order to avoid this there have been many campaigns to encourage people to regularly wash and apply antimicrobial gel to their hands. However high participation is needed for this approach to be effective. It would also be advantageous to reduce, prevent or inhibit the growth of microbes on the surfaces of hand held objects. It is an aim of the present invention to provide a method by which the growth of microbes on such objects can be reduced, prevented or inhibited. It is a further aim of the present invention to provide a coating composition which combats the growth of microbes on a surface.

According to a first aspect of the present invention there is provided a method of combating the growth of microbes on a surface of a handheld object, the method comprising:

(a) contacting the surface with a composition comprising:

(i) a polymer precursor compound;

(ii) a cationic biocide;

(iii) a hydrocarbyl-saccharide compound;

(iv) and a compound of formula (I): FT R n+

R ⁵ N L Si R ²

R~

(I) or a derivative salt thereof; wherein L is a linking group; each of R , R ² and R ³ is independently selected from an optionally substituted alkyl, alkenyl, aryl or alkoxy group; R ⁴ is oxygen or an optionally substituted alkyl, alkenyl or aryl group; each of R ⁵ and R ⁶ is an optionally substituted alkyl, alkenyl or aryl group; and n is 0 or 1 ; and (b) causing the composition to form a coating on the surface.

According to a second aspect of the present invention there is provided an antimicrobial composition comprising: (i) a polymer precursor compound;

(ii) a cationic biocide; a hydrocarbyl-saccharide compound;

(iv) and a compound of formula (I):

R ^q R ' n+

R ⁵ N L Si R ²

R ^c R~

(I) or a derivative salt thereof; wherein L is a linking group; each of R , R ² and R ³ is independently selected from an optionally substituted alkyl, alkenyl, aryl or alkoxy group; R ⁴ is oxygen or an optionally substituted alkyl, alkenyl or aryl group; each of R ⁵ and R ⁶ is an optionally substituted alkyl, alkenyl or aryl group; and n is 0 or 1 . Preferred features of the first and second aspects of the invention will now be defined.

The first aspect of the present invention relates to a method of combating the growth of microbes on a surface of a handheld object. By handheld object we mean to refer to a portable object. Such an object may be capable of being held in the hand or it may be an object which can be carried by holding part of the object. We do not mean to refer to very heavy or bulky items which are cumbersome or difficult to carry. The invention is suitable for use with any such object. Objects which are often passed around and moved or carried by more than one person present a high risk for cross-contamination.

The present invention may be particularly suitable for the treatment of objects used in food preparation areas, in medical or laboratory environments or in the home. The present invention may be particularly useful for combating the growth of microorganisms on the surface of containers, for example bottles, jars, cartons and the like. The method may also be used to treat the surface of labels or lids for such containers.

In some embodiments the object comprises a flexible sheet material.

The surface of the object may comprise any suitable material including plastic, glass, metal, fabric, paper and card.

The present invention is particularly useful for providing coatings on labels.

The method of the present invention involves contacting a surface of the object with a composition comprising components (i), (ii), (iii) and (iv).

The method of the present invention suitably involves contacting a surface of the object with a composition of the second aspect. Component (i) comprises a polymer precursor compound. By a polymer precursor compound we mean to refer to a compound which may form a polymer either alone or in combination with one or more additional compounds; and/or a compound which may form a polymer upon application of a stimulus. In some embodiments the polymer precursor compound may comprise a single monomer which is able to polymerise with itself. In some embodiments the composition may comprise a mixture of polymer precursor compounds, that is the combination of two or more monomers which together react to form a copolymer. In some embodiments component (i) may comprise a polymer precursor compound which is able to form a polymer upon addition of a catalyst.

In some embodiments component (i) may comprise a polymer precursor compound able to form a polymer upon application of a stimulus, for example by application of heat or light, for example ultra violet light.

The composition of the second aspect of the present invention is preferably a coating composition. Preferably the composition is a film-forming composition.

The composition used in the method of the first aspect present invention forms a coating on the surface of the object. Preferably the composition is a film-forming composition.

For the avoidance of doubt, references herein to "the composition" or "the composition of the present invention" may refer to the composition used in the method of the first aspect or the composition of the second aspect. In preferred embodiments, as mentioned above the composition used in the method of the first aspect is a composition according to the second aspect. The composition may suitably be applied to a surface to provide a film coating. Suitably the surface is visible through the coating. Thus the composition of the present invention is preferably able to form a transparent or translucent film coating. Preferably the composition of the present invention is able to provide a transparent film coating. The composition may include a colouring agent, for example a pigment or dye. Preferably it does not comprise sufficient colouring agent to mark a surface beneath the coating once it has been applied.

In some preferred embodiments the composition does not contain a colouring agent. Suitably it is colourless.

The composition used in the method of the first aspect of the present invention may be aqueous based, or it may be solvent based. Suitable solvents include hydrocarbon solvents and alcohols. Mixtures of solvents may be used. In some embodiments the composition may comprise a mixture of water and one or more water miscible solvents.

The composition of the present invention is preferably an antimicrobial varnish composition. The composition preferably comprises a base varnish composition and further comprises (ii) a cationic biocide, (iii) a hydrocarbyl-saccharide and (iv) a compound of formula (I). Any suitable base varnish composition may be used. The base varnish composition preferably comprises a polymer precursor compound. Suitable base varnish compositions will be known to the person skilled in the art.

Step (a) of the method of the first aspect of the present invention may suitably involve contacting a surface of a handheld object with an antimicrobial varnish composition comprising: (i) a base varnish composition including a polymer precursor compound;

(ii) a cationic biocide;

(iii) a hydrocarbyl-saccharide compound; and

(iv) a compound of formula (I) as defined herein. The second aspect of the present invention may suitably provide an antimicrobial varnish composition comprising:

(i) a base varnish composition including a polymer precursor compound;

(ii) a cationic biocide;

(iii) a hydrocarbyl-saccharide compound; and

(iv) a compound of formula (I) as defined herein.

Any varnish composition may be used as the base varnish composition. Many different types of varnish are available commercially and these will be known to the person skilled in the art.

In some embodiments the base varnish composition may be a solvent based varnish composition. By a solvent-based varnish composition we mean to refer to a varnish composition in which the major diluent or carrier is an organic solvent. Some solvent based varnishes typically comprise an oil, a resin and a solvent. Examples of suitable oils include linseed oil, tung oil and walnut oil. Other suitable oils will be known to the person skilled in the art. In such varnish compositions the polymer precursor compound is a resin. Suitable resins will also be known to the person skilled in the art and include for example amber, kouri gum, dammar, copal, rosin, sandarac, balsam, elemi and mastic.

Suitable solvents include hydrocarbon solvents, for example turpentine and distillates from petroleum. Other solvents such as butyl acetate, xylene or toluene may also be included. Alternative and additional components of solvent based varnishes will be known the person skilled in the art. In some embodiments the base varnish composition may be a polyurethane base varnish composition. Varnishes of this type will be known to the person skilled in the art. Some suitable base varnish compositions are alcohol based. Varnishes of this type will be known to the person skilled in the art and are typically ethanol based. Shellac is commonly included in alcohol based varnishes.

In some preferred embodiments the composition of the present invention comprises an aqueous based varnish composition. By aqueous based varnish composition we mean to refer to a varnish composition in which water is the major solvent present. Other water miscible solvents may also be present, but at lower amounts than water.

Suitable aqueous based varnish compositions will be known to the person skilled in the art. Particularly preferred aqueous base varnish compositions for use herein include those comprising acrylic compounds. Suitable acrylic based varnishes will be known to the person skilled in the art. Preferably the composition of the present invention comprises an optionally substituted acrylic acid compound. Preferably component (i) comprises as the polymer precursor compound a compound of formula CHR CHR ² COOX in which each of R and R ² is independently selected from hydrogen and a to C ₄ alkyl group and X is selected from NH ₄ ⁺ , an alkali metal cation, hydrogen and a to C ₄ alkyl group. Preferably each of R and R ² is independently selected from hydrogen and methyl. Preferably R is hydrogen. Preferably R ² is hydrogen or methyl. Most preferably R ² is hydrogen. X is preferably selected from sodium, hydrogen and methyl. In some embodiments X is methyl. In some embodiments X is sodium. Preferably X is hydrogen. When the base varnish is an acrylic based varnish composition it may include only acrylic acid derived monomers and/or it may include one or more further monomers. Further monomers may be selected from acrylamides, acrylonitriles, vinyl, styrene and butadiene. In some preferred embodiments component (i) of the composition of the present invention includes both acrylic acid derived monomers and styrene derived monomers.

The composition of the present invention is suitably a liquid composition. It may be runny or viscous. In some embodiments it may be very viscous like a gel or paste. However it is suitably of a form which can be spread out across a surface. The composition is suitably a curable composition. By this we mean that the composition is such that it may be coated onto a surface as a film and allowed to cure or harden.

In some embodiments curing of the composition may be induced by evaporation of the solvent. In such embodiments the time taken for curing to occur will depend on the nature of the solvent used and the ambient conditions. In some embodiments the composition of the present invention may be curable upon application of a stimulus. For example the composition may be heat curable or curable upon application of ultra violet light. In some embodiments the composition may include a catalyst in order to effect curing.

Suitably the composition of the present invention comprises from 10 to 95 wt% of the polymer precursor compound, suitably from 20 to 80 wt%, preferably from 30 to 60 wt%. The composition of the present invention comprises a cationic biocide (ii).

Preferred cationic biocides include quaternary ammonium based biocides and guanidine- containing biocide compounds. For the avoidance of doubt, the one or more cationic biocides is present in addition to the compound of formula (I) which is further described below.

Preferably the composition comprises at least 0.001 wt% of cationic biocide, preferably at least 0.01 wt%, more preferably at least 0.05 wt%, preferably at least 0.1 wt%, suitably at least 0.2 wt%, preferably at least 0.3 wt%, more preferably at least 0.4 wt%, suitably at least 0.45 wt%, preferably at least 0.5 wt%.

The composition may comprise up to 30 wt% cationic biocide, for example up to 25 wt%, up to 20 wt%, up to 15 wt% or up to 12 wt%.

In some embodiments the composition may comprise up to 10 wt% cationic biocide component (c), suitably up to 7.5 wt%, preferably up to 5 wt%, for example up to 3 wt%, preferably up to 2wt%, more preferably up to 1 wt%, suitably up to 0.8 wt% or up to 0.7 wt%. In some embodiments the composition may comprise from 0.3 to 1 wt% cationic biocide.

In some embodiments the composition may comprise from 1 .5 to 2.5 wt% cationic biocide.

In some embodiments the composition may comprise from 2 to 4 wt% cationic biocide. The composition may comprise a mixture of two or more cationic biocide components. In such embodiments the above amounts refer to the total of all such cationic biocides present.

The cationic biocide may be provided with a diluent or carrier. Suitable diluents and carrier will be known to the person skilled in the art. The above amounts refer to the actual amount of active component present in the composition and do not include any diluent or carrier which may be present when the cationic biocide is added.

Preferably the cationic biocide is selected from quaternary ammonium based biocides, guanidine-containing biocide compounds and mixtures thereof.

In some preferred embodiments the cationic biocide comprises a guanidine derived cationic biocide.

Suitable guanidine derived cationic biocide compounds for use herein include guanidine based compounds, diguanidine based compounds and polymeric guanidine based compounds.

Suitable guanidine based compounds include biguanidine and polymeric guanidine compounds of formula (VI):

wherein X ¹ and X ² are either a hydrogen or any aliphatic, cycloaliphatic, aromatic, substituted aliphatic, substituted aromatic, heteroaliphatic, heterocyclic, and/or heteroaromatic compound. X ¹ and X ² can be the same or different. Y and Y ² are any aliphatic, cycloaliphatic, aromatic, substituted aliphatic, substituted aromatic, heteroaliphatic, heterocyclic, and/or heteroaromatic compound. Y and Y ² can be the same or different. M is a number equal to or greater than 1 . Typically, M has an average value such that the molecular weight of the biguanide compounds is about 1000-1400; however, the molecular weight can be higher or lower. Generally M is about 2-20. Z and Z ² are either a hydrogen or a salt. Z and Z ² can be the same of different. In another and/or alternative aspect of this embodiment, the above-mentioned organic materials can be modified to include a thiol group in their structure so as to allow for the bonding of the compound to a metallic substrate, and/or may be derivatized with other functional groups to permit direct immobilization on a non-metallic substrate. In still another and/or alternative aspect of this embodiment, the above-mentioned organic materials may also be suitably functionalized to incorporate groups such as, but not limited to, hydroxy, amine, halogen, epoxy, alkyl and/or alkoxy silyl functionalities to enable direct immobilization to a surface. In yet another and/or alternative aspect of this embodiment, the salt can include, but is not limited to, salts with an inorganic acid such as, but not limited to, hydrochloride, hydrofluoride, nitrate, sulfate and/or phosphate, and/or salts with an organic acid such as, but not limited to, carboxylic acid, acetate, benzoate, tartrate, adipate, lactate, formate, maleate, glutamate, ascorbate, citrate, gluconate, oxalate, succinate, pamoate, salicylate, isethionate, succinamate, mono-diglycollate, dimethanesulfonate, di-isobutyrate, and/or glucoheptonate. Specific examples of these compounds include, but are not limited to, polyhexamethylene biguanide hydrochloride, p-chlorophenyl biguanide, and 4-chlorobenzhydryl biguanide. In still yet another and/or alternative aspect of this embodiment, the biguanide compound includes, but is not limited to, halogenated hexidine such as, but not limited to, chlorhexidine (1 ,1 - hexamethylene-bis-5-(4-chlorophenyl biguanide) and its salts. The salts include, but are not limited to, salts with an inorganic acid, such as hydrochloride, hydrofluoride, nitrate, sulfate and/or phosphate, and/or salts with an organic acid such as, but not limited to, carboxylic acid, acetate, benzoate, tartrate, adipate, lactate, formate, maleate, glutamate, ascorbate, citrate, gluconate, oxalate, succinate, pamoate, salicylate, isethionate, succinamate, mono- diglycollate, dimethanesulfonate, di-isobutyrate, and/or glucoheptonate. Examples of salts of chlorhexidine include, but are not limited to, chlorhexidine diphosphanilate, chlorhexidine digluconate, chlorhexidine diacetate, chlorhexidine dihydrochloride, chlorhexidine dichloride, chlorhexidine gluconate, chlorhexidine dihydroiodide, chlorhexidine diperchlorate, chlorhexidine dinitrate, chlorhexidine sulfate, chlorhexidine sulfite, chlorhexidine thiosulfate, chlorhexidine di-acid phosphate, chlorhexidine difluorophosphate, chlorhexidine diformate, chlorhexidine dipropionate, chlorhexidine di-iodobutyrate, chlorhexidine di-valerate, chlorhexidine dicaproate, chlorhexidine malonate, chlorhexidine succinate, chlorhexidine malate, chlothexidine tartrate, chlorhexidine dimonoglycolate, chlorhexidine monodiglycolate, chlorhexidine dilactate, chlorhexidine di-alpha-hydroxyisobutyrate, chlorhexidine diglucoheptonate, chlorhexidine di-isothionate, chlorhexidine dibenzoate, chlorhexidine dicinnamate, chlorhexidine dimandelate, chlorhexidine di-isophthalate, chlorhexidine di-2- hydroxynapthoate, and chlorhexidine embonate.

Especially preferred diguanidine cationic biocides for use herein include polyhexamethylene biguanide, chlorhexidine and salts and mixtures thereof. Suitably the composition comprises from 0.01 to 5 wt%, preferably from 0.1 to 2.5 wt% of a guanidine derived cationic biocide.

In some embodiments the composition comprises from 0.1 to 1 wt%, preferably from 0.4 to 0.8 wt% of a guanidine derived cationic biocide. In some embodiments the composition comprises from 0.5 to 2 wt%, preferably from 1 .0 to 1 .5 wt% of a guanidine derived cationic biocide.

In some embodiments the cationic biocide comprises a quaternary ammonium salt.

In some embodiments component (ii) includes a quaternary ammonium salt and a guanidine based cationic biocide.

Suitable quaternary ammonium cationic biocides for use herein have the structure shown in formula (V):

R +

R ² N R ⁴ X

R ³

(V) where each of R , R ² , R ³ and R ⁴ is an optionally substituted alkyl, alkenyl, alkylaryl or aryl group and X ^" is a suitable anion. Preferably each of R , R ² , R ³ and R ⁴ is an optionally substituted alkyl or alkylaryl group, more preferably an unsubstituted alkyl or alkylaryl group.

Any suitable anion X ^" may be used. X may be selected from halide, acetate, nitrite, a lower alkyl sulfate, carbonate or alkyl carboxylate. Preferably X is chloride or bromide.

Each of R , R ² , R ³ and R ⁴ may be an unsubstituted alkyl group having from 1 to 30 carbon atoms or an alkylaryl group, for example a benzyl group. Preferably at least one of R , R ² , R ³ and R ⁴ is an unsubstituted alkyl group having at least 6 carbon atoms, preferably at least 8 carbon atoms.

In one preferred embodiment R is an alkyl group having from 6 to 30 carbon atoms, preferably from 8 to 24 carbon atoms, suitably from 8 to 20 carbon atoms, for example from 10 to 18 carbon atoms and most preferably from 12 to 16 carbon atoms; each of R ² and R ³ is an alkyl group having from 1 to 4 carbon atoms, preferably methyl and R ⁴ is an alkylaryl group, preferably benzyl. Thus a particularly preferred cationic biocide for use herein is a benzyldimethylalkyl ammonium chloride or bromide in which the alkyl group has from 12 to 16 carbon atoms. The skilled person will appreciate that such compounds may often be present as a mixture of homologues. In another preferred embodiment the cationic biocide of formula (VI) is one in which each of R and R ² is an alkyl group having from 6 to 20 carbon atoms, preferably from 6 to 16 carbon atoms, suitably from 8 to 12 carbon atoms, for example from 8 to 10 carbon atoms; and R ³ and R ⁴ is each an alkyl group having 1 to 4 carbon atoms, preferably methyl. One especially preferred cationic biocide for use herein is didecyldimethyl ammonium chloride or bromide.

In some embodiments the composition of the present invention comprises from 0.1 to 10 wt% of quaternary ammonium cationic biocide, preferably from 0.5 to 5 wt%, suitably from 1 to 3 wt%, for example from 1 .5 to 2.5 wt%.

In some embodiments the composition comprises from 0.5 to 5 wt%, preferably 1 to 3 wt% of a quaternary ammonium biocide and from 0.1 to 2.5 wt%, preferably from 1 to 1 .5 wt% of a guanidine based cationic biocide. The composition of the present invention comprises a hydrocarbyl-saccharide compound (iii). By this we mean to refer to a compound including a hydrocarbyl group and a saccharide moiety.

The hydrocarbyl group may be bound to the saccharide moiety via a carbon-carbon bond or via a carbon-oxygen bond. Preferably it is bound to the saccharide moiety via a carbon- oxygen bond, for example via an ester linkage or an ether linkage. Most preferably it is bound to the oligosaccharide moiety via an ether linkage. Thus in preferred embodiments the composition of the present invention comprises a hydrocarbyl ether of a saccharide moiety. The hydrocarbyl-saccharide compound may include one or more hydrocarbyl groups. Preferably it comprises one hydrocarbyl group. The hydrocarbyl group may be an optionally substituted alkyl, alkenyl or alkynyl group. Most preferably it is an optionally substituted alkyl group. Suitable substituents include halo, hydroxy, nitro, mercapto, amino, alkyl, alkoxy, aryl, sulfo and sulfoxy. Any subsubstitution may be within the chain or along it, for example the chain may include an ether linkage.

Preferably the hydrocarbyl group is an unsubstituted alkyl group. It may be straight chained or may be branched. Most preferably it is straight chained. Especially preferred hydrocarbyl groups are alkyl groups having from 1 to 30 carbon atoms, preferably 2 to 24 carbon atoms, more preferably from 4 to 20 carbon atoms, suitably from 4 to 16 carbon atoms, preferably from 6 to 14 carbon atoms, for example from 6 to 12 carbon atoms and most preferably from 8 to 10 carbon atoms. Preferred are straight chained alkyl groups having from 6 to 12 carbon atoms. The saccharide moiety of the hydrocarbyl oligosaccharide species may include from 1 to 10 monosaccharide species. Thus it may be a monosaccharide unit, a disaccharide unit or an oligosaccharide unit. Preferably the saccharide moiety comprises from 2 to 8, suitably from 2 to 6, preferably from 2 to 5, for example 3 or 4 monosaccharide units. Any suitable monosaccharide unit may be included. Preferred saccharides include allose, altrose, glucose, mannose, gulose, idose, galactose and talose.

Mixtures of two or more monosaccharides may be present in the saccharide moiety. Preferably the saccharide moiety comprises glucose. More preferably all of the monosaccharide units present in the saccharide moiety are glucose. In especially preferred embodiments the composition of the present invention comprises an alkylpolyglucoside, preferably a monoalkyl-polyglucoside. Suitably the composition comprises a compound of formula (IV):

wherein n is from 5 to 12, preferably from 6 to 10, more preferably from 7 to 9 and m is from 1 to 6, preferably from 1 to 4, more preferably 1 or 2.

The hydrocarbyl-saccharide compound may be present in the composition of the present invention in an amount of at least 0.001 wt%, preferably at least 0.01 wt%, more preferably at least 0.1 wt%, preferably at least 0.15 wt%, suitably at least 0.2 wt%, more preferably at least 0.25 wt%, preferably at least 0.3 wt%.

The hydrocarbyl-saccharide compound may be present in the composition of the present invention in an amount of up to 20 wt% or up to 15 wt%.

In some embodiments the hydrocarbyl-saccharide compound may be present in the composition in an amount of up to 10 wt%, suitably up to 5 wt%, preferably up to 3 wt%, more preferably up to 2 wt%, preferably up to 1 wt%, suitably up to 0.75 wt%, for example up to 0.5 wt%, or up to 0.4 wt%.

In some embodiments the hydrocarbyl-saccharide compound may be present in the composition of the present invention in an amount of from 0.1 to 2 wt%. In some embodiments the hydrocarbyl-saccharide compound may be present in the composition of the present invention in an amount of from 0.1 to 0.5 wt%.

In some embodiments the hydrocarbyl-saccharide compound may be present in the composition of the present invention in an amount of from 0.5 to 3 wt%, for example from 1 to 2 wt%.

The composition of the present invention may comprise a mixture of hydrocarbyl-saccharide compounds. In such embodiments the above amounts refer to all such compounds present in the composition.

The above amounts refer to the amount of active component present in the composition and do not include any diluent or carrier.

Component (iv) comprises a compound of formula (I). It will be appreciated that in embodiments in which n is 1 , the species shown in formula (I) is a cationic species.

In such embodiments the species of formula (I) will be present as an adduct or salt including a suitable counterion. However for ease of reference, in this document we may make general reference to compounds of formula (I) and any such reference includes where appropriate any counterion which must be present.

Any suitable counterion may be used. Monovalent counterions are preferred. Suitable counterions include halides and oxyhalo ions for example chloride, bromide, bromite, chlorite, hypochlorite, chlorate, bromate and iodate.

In embodiments in which R ⁴ is O, the compound has the structure shown in formula (II) and n is 0:

(ll)

In preferred embodiments in which R ⁴ is not O, n is 1 and a suitable counterion is present. In preferred embodiments R ⁴ is not oxygen and the compound of formula (I) is preferably a quaternary ammonium salt.

In this specification any optionally substituted alkyl, alkenyl, aryl or alkoxy group may be optionally substituted with one or more substituents selected from halo, hydroxy, nitro, mercapto, amino, alkyl, alkoxy, aryl, sulfo and sulfoxy.

Preferred substituents which may be present in the alkyl, alkenyl, aryl or alkoxy groups defined herein are halogens, in particular fluorine. In particular each of R , R ² , R ³ , R ⁴ , R ⁵ or R ⁶ may comprise fluoroalkyi or fluoroalkoxy groups in which one or more hydrogen atoms are substituted with fluorine.

Each of R , R ² and R ³ is independently selected from an optionally substituted alkyl, alkenyl, aryl or alkoxy group. Preferably at least one of R , R ² and R ³ is an optionally substituted alkoxy group. More preferably each of R , R ² and R ³ is an optionally substituted alkoxy group, most preferably each is an unsubstituted alkoxy group. The alkyl group of the alkoxy group may be straight chained or branched. Preferably each of R , R ² and R ³ is an alkoxy group having from 1 to 20 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, suitably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbon atoms.

In preferred embodiments each of R , R ² and R ³ is independently selected from methoxy, ethoxy, propoxy, butoxy and isomers thereof. Most preferably each of R , R ² and R ³ is selected from methoxy, ethoxy and isopropoxy. Preferably each of R , R ² and R ³ is selected from methoxy and ethoxy. Most preferably each of R , R ² and R ³ is methoxy. Preferably each of R , R ² and R ³ is the same.

In embodiments in which R , R ² and R ³ are substituted alkoxy they are preferably fluoro substituted alkoxy in which all of the hydrogen atoms have been replaced with fluorine atoms. Thus in some embodiments each of R , R ² and R ³ may be independently selected from trifluoromethoxy, pentafluoroethoxy, heptafluoropropoxy, nonafluorobutoxy and isomers thereof.

R ⁴ may be oxygen or an optionally substituted alkyl, alkenyl, or aryl group. Preferably R ⁴ is an optionally substituted alkyl group.

R ⁴ is preferably an alkyl group or a fluoro-alkyl group. When R ⁴ is a fluoroalkyi group it is preferably an alkyl group in which all of the hydrogen atoms have been replaced by fluorine. These may be referred to as perfluoro-alkyl groups. Preferred fluoroalkyi groups are those having from 1 to 20 carbon atoms, preferably 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, for example 1 to 6 carbon atoms, most preferably 1 to 4 carbon atoms. Preferred fluoroalkyl groups are trifluoromethyl, pentafluoroethyl, heptafluoropropyl, nonafluorobutyl and isomers thereof. Nonafluorobutyl is especially preferred.

Preferably R ⁴ is an alkyl group, most preferably an alkyl group having 1 to 24 carbon atoms, preferably 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, suitably 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms. Most preferably R ⁴ is selected from methyl, ethyl, propyl, butyl and isomers thereof. More preferably R ⁴ is selected from ethyl and methyl. Most preferably R ⁴ is methyl.

Each of R ⁵ and R ⁶ may be independently selected from an optionally substituted alkyl, alkenyl, aryl or alkoxy group.

Most preferably each of R ⁵ and R ⁶ is an optionally substituted alkyl or alkoxy group, most preferably an optionally substituted alkyl group. Each of R ⁴ , R ⁵ and R ⁶ may be a fluoroalkyl group in which some or preferably all of the hydrogen atoms have been replaced by fluorine atoms. Preferred fluoroalkyl groups are those having from 1 to 20 carbon atoms, preferably 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, for example 1 to 10 carbon atoms.

In embodiments in which each of R ⁵ and R ⁶ is fluoroalkyl, each may be a fluoroalkyl group having 4 to 10 carbon atoms, for example 8 carbon atoms. In some preferred embodiments each of R ⁵ and R ⁶ is an alkyl group, suitably an unsubstituted alkyl group. The alkyl group may be straight chained or branched. In such embodiments R ⁵ is preferably an alkyl group having more than 8 carbon atoms and R ⁶ is preferably an alkyl group having less than 8 carbon atoms. Preferably R ⁵ is an alkyl group having from 8 to 30 carbon atoms, for example from 10 to 26 carbon atoms, suitably from 12 to 24 carbon atoms, preferably from 14 to 22 carbon atoms, suitably from 16 to 20 carbon atoms, for example 17 to 19 carbon atoms, suitably 18 carbon atoms. R ⁶ is preferably an alkyl group having from 1 to 8 carbon atoms, most preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms. R ⁶ may suitably be selected from methyl, ethyl, propyl, butyl and isomers thereof. Preferably R ⁶ is methyl or ethyl. Most preferably R ⁶ is methyl. L is a linking group. It may suitably be a bond or an optionally substituted alkylene, alkenylene or arylene group. Preferably L is an optionally substituted alkenylene group. It may be substituted along the chain or within the chain. For example L may be an ether linking moiety, i.e. a group of formula 0(CH ₂ ) _n in which n is 1 to 12, preferably 1 to 6.

Preferably L is an unsubstituted alkylene group, more preferably an alkylene group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, suitably 1 to 8 carbon atoms, for example 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, suitably 2 to 5 carbon atoms for example 2 to 4 carbon atoms. In especially preferred embodiments L is a propylene group.

In especially preferred embodiments of the compound of formula (I), R , R ² and R ³ are each to C ₄ alkoxy, L is a C ₂ to C ₅ alkylene group, R ⁴ and R ⁶ are each to C ₄ alkyl groups and R ⁵ is a C ₂ to C ₂₄ alkyl group. Most preferably the compound of formula (I) is the compound of formula (III):

CI

(III) This compound is commercially available as a solution in methanol. It is suitably incorporated in the composition in a highly concentrated form, preferably comprising at least 90 wt% or at least 95 wt% active ingredient.

The compound of formula (I) is preferably present in the composition of the present invention in an amount of at least 0.001 wt%, preferably at least 0.01 wt%, more preferably at least 0.05 wt%, preferably at least 0.1 wt%, suitably at least 0.15 wt%, preferably at least 0.2 wt%, preferably at least 0.25 wt%, for example at least 0.3 wt%.

The compound of formula (I) may be present in the composition of the present invention in an amount of up to 20 wt%, suitably up to 15 wt%.

In some embodiments the compound of formula (I) may be present in the composition of the present invention in an amount of up to 10 wt%, preferably up to 5 wt%, suitably up to 4 wt%, preferably up to 3 wt%, preferably up to 2 wt%, for example up to 1 wt%, preferably up to 0.75 wt%, for example up to 0.5 wt%, or up to 0.4 wt%. In some embodiments the compound of formula (I) may be present in the composition of the present invention in an amount of from 0.1 to 2 wt%.

In some embodiments the compound of formula (I) may be present in the composition of the present invention in an amount of from 0.1 to 0.5 wt%.

In some embodiments the compound of formula (I) may be present in the composition of the present invention in an amount of from 0.5 to 3 wt%, for example from 1 to 2 wt%. The composition used in the method of the present invention may comprise a mixture of compounds of formula (I). In such embodiments the above amounts refer to all such compounds present in the composition.

The above amount refer to the amount of active component present and do not include any diluent or carrier.

The molar ratio of the hydrocarbyl saccharide compound to the compound of formula (I) is preferably at least 0.5:1 . Preferably it is at least 0.6:1 , for example at least 0.7:1 . The molar ratio of component (b) to component (a) may be up to 10:1 , suitably up to 8:1 , preferably up to 5:1 , for example up to 3:1 .

The weight ratio of the hydrocarbyl saccharide compound to the compound of formula (I) is preferably from 2:1 to 1 :2, more preferably from 1 .5:1 to 1 : 1 .5. Suitably it is about 1 :1 . The composition used in the present invention may comprise further components for example colourants, fragrances, preservatives and drying agents.

In some embodiments the method of the present invention may involve a step of preparing the coating composition prior to coating the surface.

Thus the present invention may provide a method of combating the growth of microbes on the surface of a handheld object, the method comprising:

(x) preparing an antimicrobial composition by admixing a base coating composition comprising a polymer precursor compound with an antimicrobial additive;

(y) contacting the surface with the antimicrobial composition prepared in step (x); and

(z) causing the composition to form a coating on the surface; wherein the antimicrobial additive comprises: a cationic biocide; a hydrocarbyl-saccharide compound;

(iv) and a compound of formula (I):

FT R ' n+

R ⁵ N L Si R ²

R ^c R~

(I) or a derivative salt thereof; wherein L is a linking group; each of R , R ² and R ³ is independently selected from an optionally substituted alkyl, alkenyl, aryl or alkoxy group; R ⁴ is oxygen or an optionally substituted alkyl, alkenyl or aryl group; each of R ⁵ and R ⁶ is an optionally substituted alkyl, alkenyl or aryl group; and n is 0 or 1 .

The present invention further provides an antimicrobial additive for a coating composition, the antimicrobial additive comprising.

(ii) a cationic biocide; a hydrocarbyl-saccharide compound; (iv) and a compound of formula (I):

R ^q R ' n+

R ⁵ N L Si R ²

R ^c R~

(I) or a derivative salt thereof; wherein L is a linking group; each of R , R ² and R ³ is independently selected from an optionally substituted alkyl, alkenyl, aryl or alkoxy group; R ⁴ is oxygen or an optionally substituted alkyl, alkenyl or aryl group; each of R ⁵ and R ⁶ is an optionally substituted alkyl, alkenyl or aryl group; and n is 0 or 1 .

The antimicrobial additive suitably comprises from 1 to 20 wt% component (ii), from 5 to 25 wt% component (iii) and from 5 to 25 wt% component (iv).

Preferably the antimicrobial additive comprises from 9 to 13 wt% component (ii), from 12 to 18 wt% component (iii) and from 12 to 18 wt% component (iv).

The antimicrobial additive is preferably provided as an aqueous composition. It may contain further water miscible solvents, for example monohydric and polyhydric alcohols, esters and methylated spirits.

Upon admixture with a base coating composition, for example a base varnish composition as defined herein, the antimicrobial additive suitably forms an antimicrobial coating of the second aspect. Step (a) of the method of the first aspect of the present invention involves contacting a surface of the object with the composition. One particular surface of an object may be contacted with the composition. A portion of the surface of an object may be contacted with the surface. In some embodiments the entire surface of an object may be contacted with the composition. For example if an object has side walls, an opening at the top and a base only the side walls may be contacted with the composition.

If an object, suitably a container has and internal and external surface suitably all of the external surface of the container may be contacted with the composition.

If an object carries a label only the label may be contacted with the composition. This may be carried out before or after the label is adhered to the object. Suitably all of the exposed outer surface of the label is contacted with the surface. Suitably the object is a container.

The composition may be contacted with the surface by any suitable means. It may be provided in the form of a runny liquid or as a viscous liquid for example as a paste, cream or gel. The composition of the present invention is suitably coated onto the surface of an article to form a film over the surface. The article is thereby provided with an antimicrobial coating.

The composition of the present invention is suitable for providing antimicrobial coatings on a wide range of articles. It is particularly useful for coating hand held items, for example bottles, tubs, boxes, jars etc. It may be used to provide a coating on any suitable material including plastic, glass, metal, paper and card.

The invention is useful for providing an antimicrobial coating on disposable articles. It may be useful for providing an antimicrobial coating on packaging.

The present invention is particularly useful for providing coatings on labels.

In some embodiments the composition may be coated onto the surface using a brush, roller, pad or the like. The composition may be sprayed onto the surface. In some embodiments the object may be immersed in the composition.

The composition forms a coating on the surface of the object. Preferably the composition does not impregnate the surface and become mixed in with the material from which the object is made.

Suitably the composition applied in step (a) of the metthod of the first aspect is a curable composition. By this we mean that the composition is such that after it has been coated onto a surface it may suitably cure or harden.

Step (b) of the method of the first aspect of the present invention involves causing the composition to form a coating on the surface.

In some embodiments step (b) may involve leaving the composition to cure under ambient conditions.

In some embodiments curing of the composition may be induced by evaporation of the solvent. In such embodiments the time taken for curing to occur will depend on the nature of the solvent used and the ambient conditions. Evaporation of the solvent may be assisted by application of heat and/or by blowing air across the surface.

In some embodiments step (b) may involve application of a stimulus to effect curing of the composition. For example step (b) may involve application of heat curable or light to the surface. It may involve application of ultra violet or infrared light. In some embodiments the composition may include a catalyst in order to assist formation of the coating. Step (b) may involve activation of the catalyst.

The method of the present invention preferably provides the surface of an object with an antimicrobial coating.

Suitably the method of the present invention provides a reduction in microbe population at the surface, compared to an object which has not been treated by the method. Suitably a reduction in microbe population is observed at the surface of an article coated with a composition of the present invention compared with an uncoated surface.

Preferably there is a reduction in microbe population of at least 80%, preferably at least 75%, more preferably at least 90%, for example at least 95%. In some embodiments a reduction in microbe population of more than 98% or more than 99% may be achieved.

The present invention may be effective at combating microbes selected from bacteria, viruses, fungi, prions, algae and mixtures thereof. In some embodiments the method of the present invention may be used to kill bacteria and thus may be regarded as a bacteriacidal treatment method.

In some embodiments the composition of the present invention may be used to kill bacteria and thus may be regarded as a bactericidal composition.

In some embodiments the method of the present invention may prevent or inhibit the growth of bacteria and thus may be regarded as an antibacterial or bacteriostatic treatment method.

In some embodiments the composition of the present invention may prevent or inhibit the growth of bacteria and thus may be regarded as an antibacterial or bacteriostatic composition.

In some embodiments the method of the present invention may kill viruses and thus may be regarded as a virucidal treatment method. In some embodiments the composition of the present invention may kill viruses and thus may be regarded as a virucidal composition.

In some embodiments the method of the present invention may prevent or inhibit the growth of viruses and may be regarded as antiviral treatment method. In some embodiments the composition of the present invention may prevent or inhibit the growth of viruses and may be regarded as antiviral composition.

In some embodiments the method of the present invention may kill fungi and thus may be considered as a fungicidal treatment method.

In some embodiments the composition of the present invention may kill fungi and thus may be considered as a fungicidal composition. In some embodiments the method may prevent or inhibit the growth of fungi and thus may be regarded as antifungal.

In some embodiments the composition may prevent or inhibit the growth of fungi and thus may be regarded as antifungal.

In some embodiments the method of the present invention may kill algae and/or may prevent or inhibit the growth of algae.

In some embodiments the composition of the present invention may kill algae and/or may prevent or inhibit the growth of algae.

In some embodiments the composition of the present invention may destroy prions present at the surface to which it is applied or may restrict or inhibit the attachment of prions. It is believed that compounds of formula (II) in which R ⁴ is O are particularly effective for combating prions.

In some embodiments the present invention may be useful at combating spores of such pathogens. By combating spores we mean that the composition may kill spores (have sporicidal activity) and/or may prevent or inhibit the growth of further spores.

The present invention may be useful in combating bacteria including one or more of Clostridium difficile, Methicillin-resistant Staphylococcus aureus, Salmonella typhimurium, Leigonella and Listeria monocytogenes. The present invention may be useful in combating fungi including one or more oi Aspergillus niger and Candida albicans.

The present invention may be useful in combating viruses including Influenza A Virus subtype H1 N1 . The present invention may be useful in combating prion attachment of a surface to which it is applied, thus disrupting the transmission of such species.

The present invention will now be further defined with reference to the following non-limiting examples.

Example 1

A composition of the present invention was prepared by adding the following components to 50 grams of a base varnish composition:

0.17g of a compound of formula [Ci ₈ H37N(CH3)2(CH ₂ )3Si(OCH3)3] ⁺ cr

0.17g of alkyl polyglucoside comprising a mixture of isomers of formula:

where n = 7 or 9 and m = 1 to 5

0.3g polyhexamethylene biguanide. The base varnish composition was an aqueous zinc containing styrene acrylic polymer dispersion.

The composition was mixed well and then used to coat glass microscope slides. The coated slides were dried in an oven overnight at 40°C. Control slides were dried in an oven overnight at 40°C.

The mean bacterial counts of the test organisms Escherichia Coli ATCC 8739 and Staphylococcus aureus ATTC 6538P were measured according to the method of IS0221 96/JIS Z 2801 . The results are shown in table 1 : Table 1

Example 2

An antimicrobial varnish composition was prepared by adding the following components to 50g of an acrylate-containing base varnish composition:

0.17g of a compound of formula [Ci ₈ H37N(CH3)2(CH ₂ )3Si(OCH3)3] ⁺ cr

0.17g of alkyl polyglucoside comprising a mixture of isomers of formula:

where n = 7 or 9 and m = 1 to 5

0.3g polyhexamethylene biguanide.

After this period, the varnish was coated onto two sets of labels A and B. The labels were adhered to polystyrene bottles and left for two months.

Following this period the antibacterial properties of the surfaces were tested.

The bacterial count at the surface of the bottles having the labels was compared to the bacterial count of a comparative plastic bottle having no label, using the method of ISO 22196. Test organisms Esherichia Coli NCTC 10418 and staphylococcus aureus NCTC 10788 were contacted with the surface and the bacteria count again measured after 3 hours.

The results are shown in table 2 and table 3

Table 2

Table 3

Example 3

A composition was prepared by adding the following components to 50g of an aqueous solution comprising 35 to 40 wt% methyl methacrylate:

0.17g of a compound of formula [Ci ₈ H ₃₇ N(CH3)2(CH ₂ )3Si(OCH3)3] ⁺ cr

0.17g of alkyl polyglucoside comprising a mixture of isomers of formula:

where n = 7 or 9 and m = 1 to 5 0.3g polyhexamethylene biguanide. A plastic bottle was dipped into the composition for 1 5 seconds and then allowed to dry under ambient conditions. The surface of the bottles had improved resistance to microbial growth.

Example 4

Compositions of the present invention were prepared by adding the components listed in table 4 to an acrylate-containing base varnish composition.

Table 4

The above amounts refer to the amounts refer to the amount of active compound added to the varnish ignoring any diluent or carrier.

Compound (II I) the compound of formula [Ci ₈ H37N(CH3)2(CH2)3Si(OCH ₃ )3] ⁺ cr

APG is an alkyl polyglucoside comprising a mixture of isomers of formula:

where n = 7 or 9 and m = 1 to 5

PHMB is polyhexamethylene biguanide DDAC is didecyldimethyl ammonium chloride Example 5

The compositions prepared in example 4 were coated onto labels using a dip coating process followed by UV curing, and were tested according to method ISO: 22196 : 201 1 . The test organism was Staphylococcus aureus ATCC 6538P NCTC 7447 and a contact time of 30 minutes was used. 10mls neutraliser was used comprising L-histidine 1 g/L, L-cysteine 1 g/L, Lecithin 3g/L, Tween 80 30g/L. Labels were cut to size using a craft punch and applied to the bottom of a Petri dish in triplicate. 50μΙ of the test organism suspension was pipetted onto each test surface and spread using a sterile spreader. After the contact time, samples were flooded with neutralizer and recovered using the dilution-neutralisation method. Samples were plated using Petrifilm plates and incubated for 24hrs at 37°C. The results are shown in table 5.

Table 5

Example 6

The method of example 6 was repeated except on this occasion the labels were wiped with a damp cloth following application of the composition but prior to testing. The results are shown in table 6.

Table 6

Example 7

The compositions of example 4 were tested as follows: Labels were cut to size using a craft punch and applied to the top of a Petri dish. Samples were inoculated with the test organism suspension using a saturated swab. After 10 minutes contact time, a hydrated Petrifilm plates was pressed onto each sample. Samples were then reinoculated and the process repeated for 10 inoculations. The results are shown in table 7. Table 7

Key + bacterial growth present - <14 colonies present