GB1571357A

GB1571357A - Storable solid compositions for dilution with water to form aqueous peracid solutions

Info

Publication number: GB1571357A
Application number: GB51233/77A
Authority: GB
Original assignee: Schuelke and Mayr GmbH
Current assignee: Schuelke and Mayr GmbH
Priority date: 1976-12-08
Filing date: 1977-12-08
Publication date: 1980-07-16
Also published as: ATA794177A; DE2655599A1; NO774178L; NO146621B; FI773513A; FI60097C; CH631868A5; IE46271B1; LU78599A1; IT1090553B; DK548277A; FR2373292B1; NO146621C; FR2373292A1; BR7708103A; FI60097B; IE46271L; DE2655599B2; NL7712850A; SE7713799L

Abstract

The novel, storage-stable mixtures which, upon dissolution in water, give solutions with antimicrobial activity, contain a substance which eliminates H2O2 and one or more odourless or low-odour carboxylic anhydrides with a melting point of not below 40 DEG C. Upon dissolution in water in the presence of H2O2, these latter substances are converted into low-odour water-soluble percarboxylic acids which offer potent antimicrobial activity. The carboxylic anhydrides and/or substances which eliminate H2O2 can be coated with inert, water-soluble protective layers.

Description

(54) STORABLE, SOLID COMPOSITIONS FOR DILUTION WITH WATER TO FORM AQUEOUS PERACID SOLUTIONS (71) We, SCHULKE & MAYR G.m.b.H.. a Company organised under the laws of the Federal Republic of Germany, of Robert-Koch Strasse 2, 2000 Norderstedt, Germany, do here bv declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to storable solid compositions for dilution with water to fonn aqueous peracid solutions, which act as antimicrobial agents and may be useful as disinfectants. Percarboxylic acids make excellent disinfectants, but to be able to use them as such it is desirable to have aqueous percarboxylic acid solutions with a high percarboxylic acid content but having a slight or only weak odour.

It is known that lower aliphatic monopercarboxylic acids, such as peracetic acid and perpropionic acid, are capable of forming stable solutions with a high peracid content. However, diluted forms of these solutions ready for use, e.g. as disinfectants, are not stable over long periods of time and are therefore not suitable to be sold in that form. Unfortunately, the stable concentrated peracid solutions have an extremely pungent odour which makes handling and use of them difficult and even hazardous.

The lower dicarboxylic acids, form watersoluble percarboxylic acids with little smell. In particular maleic acid, succinic acid and glutaric acid form almost odourless, water-soluble peracids. However, diluted solutions of these peracids, ready for use, are also not stable over extended periods of time. As indicated hereinafter only perglutaric acid of these peracids is capable of forming stable concentrated solutions.

If, for example, succinic acid anhydride is reacted with H202, then the initially high content of persuccinic acid diminishes during extended storage. The decomposition of the persuccinic acid leads to succinic acid crystallising out of solution. Peracid solutions obtained from maleic acid anhydride also lack stability over long periods. Perglutaric acid solutions with a high peracid content are stable, but only in the presence of excess H2O2. The solutions there described do require careful handling, preferably by those with adequate technical knowledge. Inappropriate treatment of any concentrated percarboxylic acid solution can give rise to violent decomposition reactions and corrosion which may result in damage to material. Impurities can also lead to catalytic decomposition, while storage at too high a temperature can lead to thermal decomposition.

The known compositions do not, therefore, provide a source of peracid in solution which is storable and non-corrosive, at the same time as being easy to handle.

In one aspect this invention provides a storable, solid composition for dilution with water to form aqueous peracid solutions, which comprises an H202 source and one or more non noxious carboxylic acid anhydrides (as detained hereinafter), the melting point of the anhydride(s) being not lower than 400C.

By the term "non-noxious carboxylic acid anhydrides" is meant compdunds which are themselves odourless or have only a slight odour and which dissolve in water in the presence of H202 to form water-soluble antimicrobial peracids having no or only a slight odour. When the non-noxious anhydrides are dissolved in water in the absence of H202 they form watersoluble carboxylic acids, again having a slight odour, and advantageously such acids themselves have antimicrobial.activity.

The compositions of the invention may com prise a single carboxylic acid anhydride or a mixture of anhydrides. The anhydrides used may be simple carboxylic acid anhydrides (i.e. anhydrides of a single acid) or mixed carboxylic acid anhydrides, provided of course that they are non-noxious within the meaning of the term as set about above.

The structure - C - 0 - C II 11 0 0 can occur once, twice or n times in the anhydrides, 7t being an integer in the range 3 - 100.

Compounds with very many anhydride groups may, for example, be obtained by copolymeris ation of ethylenically-unsaturated compounds with maleic acid anhydride.

Non-noxious carboxylic acid anhydrides particularly suitable for use in the invention are readily available and include: succinic acid anhydride maleic acid anhydride glutaric acid anhydride phthalic acid anhydride itaconic acid anhydride benzoic acid anhydride diglycolic acid anhydride acetylcitric acid anhydride dichloromaleic acid anhydride 3,3-dimethylglutaric acid anhydride 7,3-dimethylmaleic acid anhydride 2-dodecen-1-yl-succinic acid anhydride homophthalic acid anhydride 3-methylglutaric acid anhydride 2-phenylglutaric acid anhydride tetramethyleneglutaric acid anhydride trimethylacetic acid anhydride 1 ,2,4,5-benzenetetracarboxylic acid anhydride 1,2,4-benzenetricarboxylic acid anhydride 1 j3-benzenetricarboxylic acid anhydride 3,3 ,4,4'-benzophenonetetracarboxylic acid di anhydride naphthalene-1 4,5,8-tetracarboxylic acid dian hydride 1 ,8-naphthalenic acid anhydride 3-nitro-plithalic acid anlWdride 3,4,9,10-perylenetetracarboxylic acid dianhy dride tetrabromo-phthalic acid dianhydride tetrachloro-phthalic acid dianhydride tetraphenyl-phthalic acid dianhydride bicycle.{2 '2,2,] -oct-7-en-2 ,3 5 ,6-tetracarboxylic acid dianhydride - DL - camphoric acid anhy dride cis,cis,cis,cis cyclopentane-1,2,3 ,4-tetra-carb- oxylic acid dianhydride cis 4cyclohexene-l ,2-dicarboxylic acid anhy dride tetrahydrofuran-2,3,4,5-tetracarboxylic acid di anhydride Particularly preferred anhydrides are: succinic acid anhydride maleic acid anhydride glutaric acid anhydride phthalic acid anhydride itaconic acid anhydride homophthalic acid anhydride 1 ,2,4,5-benzenetetracarboxylic acid anhydride and 1,2,4- and 1 ,2,3-benzenetricarboxylic acid anhydride The compositions of the invention also contain an H202 source - that is to say, a compound which when the compositions are added to water is capable of generating H202 in the formed solution so that the anhydrides are converted to corresponding peracids. Suitable H202 sources include perborates, percarbonates, monopersulphates, dispersulphates, perphosphates, percarbamides and alkali-metal peroxides.

A preferred H202 source is sodium perborate.

The acid anhydrides react with sodium perborate and the other H202 sources in aqueous solution practically immediately to form the corresponding peracids, and this reaction may be so rapid that H2O2 is not actually generated for any finite time in the solution.

Whilst succinic acid anhydride and sodium perborate are stable in juxtaposition in pulverulent formulation and mixtures of these two in ingredients are still flowable after 6 weeks, it is advantageous for other carboxylic acid anhydrides and/or other H202 sources to be encased in water-soluble, chemically inert protective coatings which dissolve quickly in water with the release of the active ingredients. The coating may prevent coagulation and lead to better storage-stability of the products. Although not necessary the active substances in a mixture of succinic acid anhydride and sodium perborate may also be encased in a protective layer.

Examples of water soluble substances for use in such coatings are fatty acids and anionic and/ or non-ionic detergents for the carboxylic acid anhydrides and non-ionic and/or anionic detergents for the H202 sources. Suitable anionic detergents are alkylbenzoic sulphonates and lauryl sulphates, and suitable non-ionic detergents are alkylphenol polyglycol ethers, polyoxypropylene glycols (Pluronic - a Registered Trade Mark) and aminoxides such as dimethyldodecylaminoxide and betaines.

Encasing the carboxylic acid anhydrides and/ or H202 sources with these materials may be carried out using known methods either before or after combining the active ingredients to form the compositions of the invention. For example, the active ingredients may be simply mixed or coated by spray drying with the inert materials. These inert materials can be used in solid form, in the form of a melt or as solution in an inert solvent, according to the method of application chosen.

The compositions of the invention may also contain water-absorbent agents capable of combining with traces of water. In this way coagulation of the compositions in the presence of moisture may be avoided so that the storability and consequently the antimicrobial activity of the disinfectant solutions prepared from the compositions may be improved. Such agents are well-known and examples include calcium chloride, calcium oxide, potassium carbonate, magnesium perchlorate, magnesium sulphate and sodium sulphate.

The molar ratio of acid anhydride to H202 source may be varied within broad ranges, preferably in the range of from 1:10 to 10:1 and is most preferably in the range 1:4 to 4:1. Preferably as many moles of sodium perborate are used per mole of anhydride as there are anhydride functions in the latter - thus, n moles of sodium perborate are used per mole of anhydride containing z anhydride functions. This gives a final pH in the range of 5 to 7, which is preferred since peracids tend to be unstable in alkaline conditions.

The compositions of the invention are solid, and may be in the form of powder or be formed into larger solid particles such as granules, pellets or tablets.

The compositions of the invention may also contain a variety of other components such as inert fillers, stabilising agents for the peracids and/or H2O2, agents for adjusting or buffering pH, corrosion inhibitors, perfumes, further antimicrobial substances, substances having cleaning activity, and a variety of inorganic and organic salts depending on the ultimate use intended for the compositions. Such additional materials are generally known, but by way of illustration, suitable stabilisers for H202 and/or the peracids are urea, alkali-metal metaphosphates, alkalimetal polyphosphates, pyridin-2,3-dicarboxylic acid, pyridin-2,6-dicarboxylic acid, citric acid and its alkali-metal salts, ethylenediaminetetracetic acid and its alkali-metal salts, and nitriloacetic acid and its alkali-metal salts. These stabilisers can be used in an amount of from 0.01 to 5% by weight of the composition, and preferably in an amount of from 0.1 to 5% by weight.

Benzotriazole, alkali-metal phosphates, alkyl phosphates and amine oxides can be used as corrosion inhibitors. These compounds are preferably employed in amounts ranging from 0.01 to 10% by weight of the composition and preferably 0.5 to 5% by weight.

Examples of further antimicrobial additives are sorbic acid, benzoic acid and salicylic acid.

To adjust and stabilise the pH value of the composition citric acid and its alkali-metal salts, alkali-metal phosphates, alkali-metal acetates, lactic acid and its alkali-metal salts, alkali-metal bisulphates, alkali-metal carbonates and alkalimetal bicarbonates may be used.

Substances with cleaning activity which may be included are, in addition to the detergents mentioned above, metaphosphates and polyphosphates.

The compositions of the invention possess good storability, dissolve in water immediately without the production of large amounts of heat of reaction and in doing so give a high yield of peracids, to form solutions having the excellent antimicrobial activity of the peracids.

The solutions formed are substantially odourless. Furthermore the carboxylic acids formed on decomposition of the peracids largely represent naturally-occurring compounds, so that they give no problems with unwanted residues.

This invention also provides a process for forming a disinfectant solution in which a composition of the invention is dissolved in water.

Naturally, the concentration of peracid in the disinfectant solution may be selected by dissolving an appropriate amount of the composition in water.

The preparation of a disinfectant solution containing a peracid by the addition to water of a composition comprising acid anhydride and a H202 source, and where present the extra additives set out above, has many advantages over a preparation comprising separate addition of the individual ingredients. By being added in an intimate mixture the ingredients go into better solution and a higher yield of active peracid is obtained. The disinfectant solution formed is more stable and its compatibility to other substances is greater.

If one puts the individual ingredients into water separately - that is, the acid anhydride first - then this anhydride is converted into acid. With the subsequent addition of the H202 source so much acid anhydride has already converted into acid that the reaction of the remaining anhydride with H202 leads to a substantially smaller peracid content. This results in insufficient disinfectant activity in the solution formed.

Conversely, if the H202 source is dissolved first, at least for a short period, a pH value is produced which can differ strongly from the final pH value of the solution. Thus, solutions may be formed with potassium monoperoxydisulphate (KIlSOs) as H202 source which are too acidic, while the use of perborates and percarbonates give solutions which are too alkaline.

Undesirable pH values can result in incompatibility with other substances and corrosion problems resulting in damage to the disinfectant solution. Above all if metal ions go into solution the peracid may be decomposed catalytically.

These disadvantages may also occur if the individual ingredients are added not one after the other but separately in the sense that (for instance, as a result of coagulation) one or other of the ingredients dissolves too slowly.

The acid anhydrides react in solution immediately with H202 or the H202 source itself to form a high yield of peracid. The solution obtained may contain, depending on whether mono- or higher functional carboxylic acid anhydrides are present and according to the ratio of acid anhydride : H202 source used, both monoperacids, diperacids and higher functional peracids, as well as mixtures of these peracids.

Moreover the solutions are sufficiently stable to produce excellent and effective antimicrobial activity.

The spectrum of activity of disinfectant solutions obtained according to the invention was established according to the methods described in "Guide Lines for the examination of chemical disinfectants", Gustav Fischer Verlag, Stuttgart, Germany. The results are shown in the following Tests, which show disinfectant solutions prepared according to the invention and tested 30 minutes and 16 hours after dissolution.

The disinfectant solutions obtainable using the compositions of the invention can be used in the food industry to disinfect medical and dental instruments and to disinfect materials, for example in hospitals.

This invention extends to a method of disinfecting a locus infected with microbes, or liable to infection by microbes, in which the locus is treated with an effective amount of a disinfectant solution produced according to the invention.

The following Examples and Tests are now given, through only by way of illustration, to show certain preferred aspects of the invention.

EXAMPLE I 1.53 g of sodium perborate and 1.0 g of succinic acid anhydride were mixed together. This mixture was dissolved in soft water to give 100 g of an aqueous solution. The solution was clear and colourless and had a pH value of 5.3. It contained: after 20 minutes 13.6 mg of H202 and 863 mg of peracid after 40 minutes 10.9 mg of H202 and 863 mg of peracid after 60 minutes 10.9 mg of H202 and 852 mg of peracid after 94 hours 63.9 mg of H202 and 346 mg of peracid.

With the addition of Na3 PO4 to adjust the pH value to 7 the solution contained: after 24 hours 46.2 mg of H202 and 158 mg of peracid.

EXAMPLE 2 A colourless, odourless, flowable powder was prepared from 10 g of succinic acid anhydride, 15 g of sodium perborate, 25 g of sodium polyphosphate of average chain length (Calgon N "CALGON" is a Registered Trade Mark) and anhydrous Na2 S04 to make up to 100 g. After 22 days' storage the mixture was dissolved in water. This solution contained: after 20 minutes 748 mg of H202 and 7742 mg of peracid after 50 minutes 680 mg of H202 and 7742 mg of peracid after 80 minutes 476 mg of H202 and 5896 mg of peracid EXAMPLE 3 10 g of finely-ground succinic acid anhydride were coated with 5 g of a fatty alcohol ethoxylate (C12 -C14 - fat alcohols with 25 ethylene oxide units) subsequently 15 g of sodium perborate, 25 g of sodium polyphosphate (Calgon N) and sodium sulphate to 100 g were added.

For comparison a) a mixture without fat alcohol ethoxylate coating; and b) a mixture without fat alcohol ethoxylate coating and without sodium sulphate where also prepared.

After 60 days' storage at room temperature the mixtureb) (without coating and without sodium sulphate) showed the formation of lumps. After a further 60 days the formation of lumps was also noticed in mixture a) (without coating). The mixture containing encased succinic acid anhydride and sodium sulphate was still satisfactory after 120 days.

Tests: Bacteriological Ltvestigation The bacteriological investigation was carried out in accordance with the "Guidelines for the Examination of Chemical Disinfectants", 3rd Edition, published on behalf of the DGHM (Deutsche Gesellschaft fer Hygiene und Mikrobiologie) by Gustav Fischer Verlag, Stuttgart, Germany, as there laid down for suspensions, germ-carriers and surfaces.

According to the DGHM Guidelines a disinfecting agent is effective if it kills the pathogenic germs (a) within 30 minutes in the suspension test and (b) within 6 hours in the surface test, at the same concentrations in each of the active substance. The germ-carriers test is a more severe one, in which absorbtive materials (such as the mineral granules and cambric respectively used below) are soaked in dispersions of the pathogenic germs before treatment with the active substance.

The results secured according to the DGHM tests were as set out in the following Tables: WHAT WE CLAIM IS: 1. A storable, solid composition for dilution with water to form aqueous peracid solutions, which comprises an H202 source and one or more non-noxious carboxylic acid anhydrides (as herein defined), the melting point of the anhydride(s) being not lower than 40"C.

2. A composition as claimed in claim 1, which comprises one or more of: succinic acid anhydride maleic acid anhydride glutaric acid anhydride phthalic acid anhydride itaconic acid anhydride benzoic acid anhydride diglycolic acid anhydride dichloromaleic acid anhydride 3,3-dimethylglutaric acid anhydride 2,3-dimethylmaleic acid anhydride 2-dodecen-1-yl-succinic acid anhydride homophthalic acid anhydride 3-methylglutaric acid anhydride 2-phenylglutaric acid anhydride tetramethyleneglutaric acid anhydride trimethylacetic acid anhydride 1,2,4,5 -benzenetetracarboxylic acid anhy dride 1,2 ,4-benzenetricarboxylic acid anhydride 1,2l3-benzenetricarboxylic acid anhydride 3,3 ,4,4'-benzophenonetetracarboxylic acid dianhydride naphthalene-1,4,5 ,8-tetracarboxylic acid di anhydride TABLE 1 Composition -1.0 g Succinic acid anhydride 1.5 g Sodium perborate Soft water to make up to 100 g.

Bacteriological results (DGHM) 30 minutes after the mixture has dissolved.

Suspension, Bacteria Suspension, Fungi Germ Carrier Staphylo- Esche Grains Cambric coccus richia aureus coli Surfaces concen- Staphylo- Klebsi- Pyo- Proteus Tricho- Candida Asper- Bacil- Mycobac- PVC Wood PVC Wood tration coccus ella genes vulgaris phyton albicans gillus lus sub- terium Var- Varaureus pneumon. menta- niger tilis smegmatis nish nish grophytes 2 > 30' > 30' > 30' > 30' 5 15' 15' 15' 30' 10 5' 5' 5' 15' 25 5' 2 ' 2 ' 2 ' 3h > 120' 1h 1h 1h 1h 50 2 ' 2 ' 2 ' 2 ' 1h > 120' 1h 1h 1h 1h 100 > 30' > 30' > 30' 1h > 120' 1h 1h 1h 1h + 20% Serum > 30' > 30' > 30' > 30' 5 > 30' > 30' > 30' 30' 10 30' 15' 15' 15' 25 2 ' 2 ' 2 ' 2 ' M H K TABLE 2 Composition: 1.0 g Succinic acid anhydride 1.5 g Sodium perborate soft water to make up to 100 g Bacteriological results (DGHM) 16 hours after the mixture has dissolved Suspension, Bacteria

Concentration Staphylo- Klebsiella Pyogenes Proteus coccus pneumon. vulgaris aureus.

10 15' 5' 1 15' 21/2' 25 2 1/2' 2 1/2' 2 1/2' 2 1/2' 50 2 1/2' 2 1/2' 2 1/2' 2 1/2' TABLE 3 Composition: A) 0.94 g Maleic acid anhydride 1.5 g Sodium percarbonate Soft water to make up to 100 g B) 1.14 g Glutaric acid anhydride 1.5 g Sodium percarbonate soft water to make up to 100 g Bacteriological results (DGHM) 30 minutes after the mixtures have dissolved Suspension, Bacteria

A) 5 > 30' 30' 15' 15' 10 15' 30' 5' 15' 25 5' 2 1/2' 2 1/2' 2 1/2' B) 5 15' 15' 5' 15' 10 5' 5' 21/2' 2 1/2' 25 2 1/2' 2 1/2' 2 1/2' 2 1/2' 1 ,8-naphthalenic acid anhydride 3-nitro-phthalic acid anhydride 3,4,9,10-perylenetetracarboxylic acid dianhy dride tetrabromo-phthalic acid dianhydride tetrachloro-phthalic acid dianhydride tetraphenyl-phthalic acid dianhydride bicyclo-[2,2,2] -oct-7en-2,3,5,6-tetracarb- oxylic acid dianhydride - DL - camphoric acid anhydride cis, cis, cis, cis cyclopentane-1 '2,3 4-tetra- carboxylic acid dianhydride cis 4-cyclohexene-l ,2-dicarboxylic acid di anhydride tetrahydrofuran-2,3,4,5-tetracarboxylic acid anhydride

Claims

3. A composition as claimed in claim 1 or claim 2, in which the H202 source is or includes a perborate, percarbonate, monopersulphate, dispersulphate, perphosphate, percarbamide or alkali-metal peroxide.

4. A composition as claimed in claim 3, in which the H202 source is sodium perborate.

5. A composition as claimed in any of the preceding claims, in which the or each carboxylic acid anhydride and/or the H202 source is encased in a water-soluble, chemically inert protective coating.

6. A composition as claimed in claim 5, in which the or each carboxylic acid anhydride is coated with a fatty acid or an anionic and/or non-ionic detergent, and/the H202 source is coated with a non-ionic and/or anionic detergent.

7. A composition as claimed in claim 6, in which the anionic detergent is an alkylbenzoic sulphonate or a lauryl sulphate and/or the nonionic detergent is an alkylphenol polyglycol ether, a polyoxypropylene glycol or an aminoxide.

8. A composition as claimed in any of the preceding claims, which also contains a waterabsorbent agent.

9. A composition as claimed in claim 8, in which the water-absorbent agent is calcium chloride, calcium oxide, potassium carbonate, magnesium perchlorate, magnesium sulphate or sodium sulphate.

10. A composition as claimed in any of the preceding claims, in which the molar ratio of acid anhydride to H202 source is in the range offrom 1:10 to 10:1.

11. A composition as claimed in claim 10, in which the molar ratio is from 1:4 to 4:1.

12. A composition as claimed in any of the preceding claims, in which the pH is in the range of from 5 to 7.

13. A composition as claimed in any of the preceding claims, which also contains one or more of inert fillers, stabilising agents for the peracids and/or H2O2, agents for adjusting or buffering pH, corrosion inhibitors, perfumes, antimicrobial substances, substances having cleaning activity, and inorganic and organic salts.

14. A composition as claimed in claim 13, in which the stabiliser for H202 and/or the peracids is urea, alkali-metal metaphosphates, alkalimetal polyphosphates, pyridin-2,3-dicarboxylic acid, pyridin-2,6-dicarboxylic acid, citric acid or an alkali-metal salt thereof, ethylenediaminetetracetic acid or an alkali-metal salt thereof, or nitriloacetic acid or an alkali-metal salt thereof.

15. A composition as claimed in claim 14, in which the stabiliser comprises from 0.01 to 5% by weight of the composition.

16. A composition as claimed in claim 15, in which the stabiliser comprises from 0.1 to 5% by weight of the composition.

17. A composition as claimed in any of claims 13 to 16, in which the corrosion inhibitor is benzotriazole, an alkali-metal phosphate, or alkyl phosphate or an amine oxide.

18. A composition as clainied in claim 17, in which the corrosion inhibitor comprises from 0.01 to 10% by weight of the composition.

19. A composition as claimed in claim 18, in which the corrosion inhibitor comprises from 0.5 to 5% by weight of the composition.

20. A composition as claimed in any of claims 13 to 19, in which the antimicrobial substance is sorbic acid, benzoic acid or salicylic acid.

21. A composition as claimed in any of claims 13 to 20, in which the pH value of the composition is adjusted or stabilised with citric acid, an alkali-metal salt thereof, an alkali-metal phosphate, an alkali-metal acetate, lactic acid or an alkali-metal salt thereof, an alkali-metal bisulphate, an alkali-metal carbonate or an alkalimetal bicarbonate.

22. A composition as claimed in any of claims 13 to 21, which contains a metaphosphase or polyphosphate.

23. A composition as claimed in any of the preceding claims, in the form of a powder, granules, pellets or tablets.

24. A composition as claimed in claim 1 and substantially as described herein with reference to any one of the Examples.

25. A process for forming a disinfectant solution in which a composition as claimed in any of claims 1 to 24 is dissolved in water.

26. A process as claimed in claim 25 and substantially as described herein with reference to any one of the Examples.

27. A method of disinfecting a locus infected with microbes, or liable to infection by microbes, in which the locus is treated with an effective amount of a disinfectant solution formed by a process as claimed in claim 25 or claim 26.

28. A method as claimed in claim 27 and substantially as described herein with reference to any one of the Tests.