WO2011026248A2

WO2011026248A2 - Disinfecting detergent composition

Info

Publication number: WO2011026248A2
Application number: PCT/CH2010/000199
Authority: WO
Inventors: Janos GÖMÖRI
Original assignee: Sanosil AG
Current assignee: Sanosil AG
Priority date: 2009-09-04
Filing date: 2010-08-17
Publication date: 2011-03-10
Anticipated expiration: 2012-03-04
Also published as: WO2011026248A3

Abstract

A composition acting both as a detergent and as a disinfectant is disclosed. The composition comprises hydrogen peroxide, a silver component, a C₈-C₁₈ alkyl polyglycol ether with a mean ethylene oxide content of 3-15 mol/mol, and a C₁₂-C₁₈ secondary alkyl sulphonate. Such a composition provides effective, fast cleaning and disinfection while being easy and safe to handle. It is mild and kind to the skin, non-toxic, ecologically friendly, and biodegradable. The product has a remarkably long shelf life.

Description

TITLE

Disinfecting Detergent Composition

TECHNICAL FIELD The present invention relates to a composition acting as a detergent, which at the same time has a disinfecting effect. Such compositions may be used as surface cleaning agents for the use in environments where a contamination with germs is to be avoided, e.g. in bathrooms, private or commercial kitchens, industrial production facilities, in particular, in the food and beverage industries, in chemical or biological laboratories, in hospitals etc., for antiseptic handwash applications, for water sanitation, and many other applications.

PRIOR ART

From the prior art, detergent compositions having both a surface-active effect and a germicidal effect are known. Such detergent compositions usually comprise an organic germicide, such as chlorhexidine or a benzalkonium chloride. Benzalkonium chlorides are quaternary ammonium salts acting as cationic surfactants. While being potent bactericides, benzalkonium chlorides are problematic both in terms of human health, being known to be caustic and possibly allergenic, and in view of the environment, being highly toxic to water organisms. Chlorhexidine, a biguanidine acting as a cationic surfactant as well, is also problematic both in view of human health and the environment.

It is therefore desirable to provide a disinfecting detergent composition exhibiting a better compliance towards human health and the environment.

For applications that are purely concerned with disinfection or sanitation, without detergent action, it has been suggested already a long time ago to utilize the oligodynamic properties of ionic silver compounds or of colloidal elemental silver in synergistic combination with the germicidal properties of hydrogen peroxide to prepare an efficient disinfectant. By the way of example, US 4,915,955 to Gomori discloses a concentrate containing an ionic silver compound or colloidal silver, which, upon admixture with hydrogen peroxide, forms a disinfectant. Such a disinfectant has a very good compliance towards human health and the environment.

However, disinfectants on the basis of hydrogen peroxide and a silver component are incompatible with many known surfactants. In particular, the presence of such surfactants may lead to a significantly decreased stability of the hydrogen peroxide, reducing the shelf life significantly and posing hazards due to significant amounts of gaseous oxygen being released from the composition. Many surfactants have a significantly decreased long-term stability themselves in the presence of hydrogen peroxide, being prone to chemical degradation in the presence of hydrogen peroxide. Other surfactants, which might be less detrimental to stability of hydrogen peroxide or less affected in their own stability by the presence of hydrogen peroxide, do not exhibit a sufficient cleaning effect.

US 6,908,628 discloses several disinfecting and antiseptic compositions comprising, in combination, hydrogen peroxide, a silver halide and lactic acid. Lactic acid appears to be an essential component of these compositions to achieve a sufficiently broad anti-microbial capacity. All these compositions further comprise at least one cationic surfactant, in particular, didecyl-methyl-polyoxy-ethyl-ammonium propionate (examples 2 and 4), chlorhexidine (examples 3 and 7.2), both these compounds (examples 5 and 6), quaternary ammonium chlorides (example 7.2.2), or ammonium propyl amide salts (example 7.2.3). These surfactants may be problematic towards the environment. Furthermore, the document does not address the problem of achieving a sufficient degree of long-term stability of the ready-to-use compositions. In fact, the document suggests that, at least for some compositions, the components of the disinfectant should be mixed only at the time of use due to a limited shelf life of the ready-to-use compositions, making it recommendable to eliminate the compositions at the end of the day. This is uneconomical and causes further environmental concerns.

DE 10 2007 003 693 discloses a disinfecting composition comprising hydrogen peroxide, colloidal silver, a solubilizer, and sodium lauryl ether sulphate as an anionic surfactant. No applications as a detergent are described. Indeed, while the components of this composition may be environmentally acceptable, such a composition will have only a limited range of action as a detergent. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a composition having both a germicidal and a detergent effect, the composition being environmentally acceptable and being sufficiently storage stable. It is a further object of the present invention to provide a composition based on a combination of hydrogen peroxide and a silver component that has improved cleaning properties.

These and other objects are achieved by a composition having the features of claim 1. Further embodiments of the invention are laid down in the dependent claims.

A composition according to the present invention comprises (all relative amounts, percentages or concentrations referring to the ready-made composition):

hydrogen peroxide in an amount of 1-15%, preferably 2-15%, more preferably 5- 10% by weight, in particular, approximately 7.5% by weight;

- at least one silver component selected from the group consisting of silver salts and colloidal silver in an amount to yield 30-300 ppm Ag by weight, preferably 50-150 ppm by weight;

at least one nonionic surfactant, the nonionic surfactant being a C₈-C]₈ alkyl polyglycol ether with a mean ethylene oxide content of 3-15 mol/mol, the nonionic surfactant being present in an amount above the critical micelle concentration (CMC) of the nonionic surfactant in the composition, preferably at least five times above the CMC; and

at least one anionic surfactant, the anionic surfactant being a Ci₂-Ci₈ secondary alkyl sulphonate in an amount above the critical micelle concentration of the anionic surfactant in the composition, preferably at least five times above the CMC.

Such a composition provides effective, fast cleaning and disinfection while being easy and safe to handle. It is mild and kind to the skin, non-toxic, ecologically friendly, and biodegradable. The product has a remarkably long shelf life. It may be supplemented with fragrances if desired. The bactericidal action of the product is much higher than it would be expected from the individual components, proving a synergistic effect between the components.

The composition may be directly used as a detergent or may be further diluted with water to obtain a diluted detergent product. Therefore the invention also encompasses a detergent product obtainable by diluting the above-described detergent composition with water to a content of the detergent composition of 0.5-100% by weight.

The product comprises at least two surfactants. The first surfactant is at least one nonionic surfactant of the class of the C₈-Ci₈ alkyl polyglycol ethers, of general formula

RO-(CH₂-CH₂-0)_n-H,

where R is a C₈-Ci8 linear or branched alkyl residue, and n is an integer typically between 3 and 15. The integer n is also called the ethylene oxide (EO) content or EO adduct number. It corresponds to the number of moles of ethylene oxide contained in one mole of the surfactant and may therefore be expressed with the unit of mol/mol. The EO content is usually strongly polydisperse, following a broad distribution, and the mean EO content is usually provided to characterize a particular alkyl polyglycol ether. In the U.S. literature, sometimes the EO content is instead given in percent by mass. The EO content in percent by mass, EO%, may be calculated from the EO content n in mol/mol by the following formula:

EO% = 44 n / (44 n + M_R0H),

where MROH is the molar mass of the alcohol ROH.

The second surfactant is at least one anionic surfactant of the class of the Ci₂-Cj₈ secondary alkyl sulphonates, of general formula R-S0₂-OM, where R is a Ci₂-Ci₈, preferably Ci₄-C₁₇ secondary alkyl residue and M is a monovalent cation, usually sodium. Alkyl sulphonates are environmentally acceptable anionic surfactants with good solubility in water. Preferably, the anionic surfactant is a sodium salt of a C]₄-Ci₇ secondary alkyl sulphonate. Such a surfactant is available commercially, e.g., from Clariant GmbH, Frankfurt a.M., Germany as a 30% solution under the brand name "Hostapur SAS 30"™. It has been found that the presence of these two particular classes of surfactants results in several remarkable properties of the composition. The composition exhibits an extremely high efficacy both as a detergent and as a disinfectant in a broad spectrum of applications, while at the same time providing a remarkably increased stability of both the hydrogen peroxide and the surfactants themselves in the composition. The combination of these two particular classes of surfactants avoids possible gaps in the cleaning action that might appear in the absence of one of the surfactants, or that might appear if one of the surfactants is replaced by another surfactant. As a disinfectant, the composition acts against a wide range of germs, including gram positive and gram negative bacteria, viruses, yeast, fungi and algae. The action as a disinfectant is remarkably increased over the action of any of the components alone and over the subcombinations of the components, proving an unexpected synergistic effect between the components in the composition of the invention. In particular, the composition exhibits an anti-microbial activity that is remarkably higher than the anti-microbial activity of the composition in absence of the surfactants or of the anti-microbial activity of the surfactants alone.

For high efficacy, each of the surfactants should be present in an amount above its respective critical micelle concentration (CMC) and preferably in an amount of at least five times the CMC. The CMC may be determined by standard methods known in the art, in particular by surface tension measurements, the surface tension being known to substantially decrease with increasing surfactant concentration below the CMC and to remain substantially constant above the CMC. Such measurements may be readily automated, automatic surface tension measurement devices being known in the art. Other known methods for CMC determination are based on dye binding via fluorescence measurements, Stokes shift measurements, interface tension measurements at the interface to hydrophobic fluids, or on density measurements. For a Cg-Cig alkyl polyglycol ether with an EO content of 3-15 mol/mol, the CMC in water is roughly in the range of 5-200 ppm. Preferably, the one or more nonionic surfactant are present in a total amount of at least 1000 ppm (0.1%) by weight, in particular between 0.5% and 10% by weight, preferably between 2% and 8% by weight, in particular approximately 4% by weight. The at least one anionic surfactant is preferably present in an amount of at least 1000 ppm (0.1 %) by weight, in particular between 0.1% and 3% by weight, preferably between 0.1% and 1% by weight, in particular approximately 0.3% by weight.

The (total) amount of nonionic surfactants is preferably at least three times, more preferably at least five times, most preferably at least 10 times the (total) amount of anionic surfactants, a too high relative content in anionic surfactants being detrimental to both stability and efficacy.

The total content of surfactants in the composition will generally be at least approximately 0.1% by weight, preferably between 0.5% and 15% by weight, more preferred between 2% and 10% by weight.

The nonionic surfactant is preferably a Cio-C|₄ alkyl polyglycol ether. The range of 10-14 carbon atoms in the alcohol residue is particularly suited to provide a good cleaning action of the surfactant, in particular, in combination with the anionic surfactant. In particular, the nonionic surfactant is preferably selected from the group consisting of:

isotridecyl polyglycol ethers with a mean ethylene oxide content of 3-10 mol/mol, and

C] i-oxo alcohol polyglycol ethers with a mean ethylene oxide content of 10-12 mol/mol.

Isotridecyl polyglycol ethers are available, e.g., from Clariant under the brand name "Genapol X"™. They may be obtained with varying mean EO content, at least in the range 2-15 mol/mol. Their properties vary with the degree of ethoxylation. By the way of example, isotridecyl polyglycol ether with an EO content of 5 mol/mol, available as "Genapol X 050"™, has a strong degreasing effect, while isotridecyl polyglycol ether with an EO content of 8 mol/mol, available as "Genapol X 080"™, has excellent wetting capabilities. Oxo alcohols are primary, partially branched alcohols that may be obtained from an oxo synthesis, by hydrating oxo aldehydes or their primary aldocondensation products catalytically to obtain the corresponding alcohols. Cn-oxo alcohol polyglycol ethers are commercially available, e.g., from Clariant under the brand name "Genapol UD"™. In particular, a Cn-oxo alcohol polyglycol ether with a mean EO content of approximately 1 1 mol/mol is available under the brand name "Genapol UD 1 10"™.

In preferred embodiments, the composition comprises at least a first and a second nonionic surfactant, the first nonionic surfactant being an isotridecyl polyglycol ether with a mean ethylene oxide content of 3-10 mol/mol, and the second nonionic surfactant being a Cn- oxo alcohol polyglycol ether with a mean ethylene oxide content of 10-12 mol/mol, in particular, approximately 1 1 mol/mol. This particular combination if nonionic surfactants remarkably increases the range of action as a detergent without compromising disinfecting action or stability of the hydrogen peroxide. In particular, the presence of the Cn-oxo alcohol polyglycol ether, having a relatively low number of carbon atoms and a distribution of linear and branched residues while having a relatively high EO content, very efficiently complements the isotridecyl polyglycol ether with its higher number of carbon atoms and its lower EO content. The amount of the first nonionic surfactant is preferably at least three times, more preferred at least five times the content of the second nonionic surfactant.

The range of action as a detergent may be further optimized by providing at least a first, a second and a third nonionic surfactant, the first nonionic surfactant being an isotridecyl polyglycol ether with a mean ethylene oxide content of 7-9 mol/mol, in particular, approximately 8 mol/mol, the second nonionic surfactant being an isotridecyl polyglycol ether with a mean ethylene oxide content of 4-6 mol/mol, in particular, approximately 5 mol/mol, and the third nonionic surfactant being a Cn-oxo alcohol polyglycol ether with a mean ethylene oxide content of 10-12 mol/mol, in particular, approximately 11 mol/mol. The amount of the first nonionic surfactant is preferably at least three times, more preferred at least five times the amount of the second and third nonionic surfactants. Preferably, the second and third nonionic surfactants are present in approximately equal amounts (relative weight ration of 0.5-2.0, preferably 0.8-1.2). The composition is preferably essentially free of cationic surfactants and/or lactic acid. The term "essentially free of means that the corresponding components are present at most in trace amounts and certainly well below 10 ppm, preferably below 1 ppm. The composition may comprise an organic or inorganic acid, in particular, one or more of phosphoric acid, nitric acid, hydrochloric acid, sulphuric acid, or boric acid. Phosphoric acid is preferred. The acid is preferably present in an amount sufficient to reduce the pH of the composition to pH 3 or lower, in order to achieve optimum long-term stability of the composition.

The composition may in addition comprise a biopolymeric stabilizer like gelatin, gum arabic, guar gum, carrageen or pectin, even though the presence of such a stabilizer is not critical due to the presence of the tensides. Such naturally occurring macromolecular biopolymers are sometimes designated in the literature as "protective colloids" that interact both with the hydrogen peroxide and the colloidal silver particles or silver ions. Gum arabic is preferred. If a biopolymeric stabilizer is present, its content is preferably above 1 ppm, in particular 2-100 ppm, preferably 5-30 ppm. In some embodiments, the silver component may be a silver salt, in particular, one or more of the silver salts selected from the group consisting of silver nitrate, silver sulphate, silver chloride, sodium/silver chloride complex, silver benzoate, silver carbonate, silver fluoride, silver (I) oxide and silver (II) oxide. Silver nitrate is preferred. The total content in silver ions of the composition should be 30-300 ppm by weight.

In particular, the composition may comprise 5-25%, preferably about 15% of the product obtainable by example III of US 4,915,955, which itself comprises, in an aqueous solution, hydrogen peroxide in an amount of 49% by volume, silver nitrate in an amount corresponding to a silver content of 1000 ppm by weight, gelatin in an amount of approximately 150 ppm by weight, and phosphoric acid to adjust the pH to below approximately pH 2.

In other embodiments, the silver component may be elemental silver in the form of colloidal silver. The amount of colloidal silver in the composition should be 30-300 ppm by weight. The term "colloidal silver" is to be understood in the usual manner in the chemical art. In particular, this term relates to any preparation of elemental silver that is sufficiently finely dispersed to form a colloid solution when dispersed in water. The mean particle size (arithmetic mean over the diameter of fictitious spheres having the same number of silver atoms) is generally in the range below 30 micrometers. Several different methods for the preparation of silver colloids exist, including, but not limited to, mechanical milling, electrolytic processes, and chemical reduction of silver salts in solution, and the invention is not limited to a silver colloid prepared by any particular method. The colloid can be provided in the form of a powder or of an aqueous dispersion ("colloid solution"). It is to be understood that colloidal silver may always also contain a certain proportion of ionic silver in addition to elemental silver due to redox reactions on the surface of the silver particles. The numerical value of the content of colloidal silver and/or silver ions, expressed in ppm by weight, preferably amounts to about eight to twelve times, most preferred about ten times, the numerical value of the concentration of hydrogen peroxide, expressed in percent by volume. To further inhibit decomposition of the hydrogen peroxide in the presence of the silver colloid and/or silver ions, the composition may comprise at least one sodium salt selected from the group consisting of sodium nitrate, sodium sulfate and combinations thereof, in an amount between 5 and 125 ppm by weight, preferably between 20 and 80 ppm by weight. It has been found that long-term stability of the hydrogen peroxide is significantly improved if sodium nitrate and/or sodium sulfate is added to the composition. The mechanism by which these sodium salts act to stabilize the composition remains unknown at present. While higher or lower concentrations might still bring about positive effects, it has turned out that the above range of concentrations brings about a good stabilizing effect with a minimum amount of sodium nitrate or sulfate. At too high concentrations, in particular, at concentrations much larger than 500 ppm by weight, undesired precipitates may form. Preferably, the sodium salt is sodium nitrate.

The composition is preferably essentially free of any added synthetic organic complexing agents, in particular, polyhydroxyl carboxylic acids, forming complexes with silver. Such agents were used in the prior art to stabilize colloidal silver solutions, but may be environmentally or pharmacologically problematic. The term "essentially free of synthetic organic complexing agents" is generally to be understood to mean that such agents are present at the most in trace amounts that are too low to bind any significant amount (less than a few percent, in particular, less than 5%, preferably less than 1%) of the silver present in the concentrate.

In particular, the composition may comprise 5-25%, preferably about 15% of a disinfecting concentrate comprising:

hydrogen peroxide in an amount of 30-70 % by volume;

colloidal silver in an amount of 150-1000 ppm by weight;

optionally, a stabilizer comprising at least one biopolymer, the stabilizer being present in an amount of 10-100 ppm by weight;

phosphoric acid in an amount effective to adjust the pH value of the concentrate to less than or equal to 3.0, preferably in a concentration of less than or equal to 500 ppm by weight; and

at least one sodium salt selected from the group consisting of sodium nitrate and sodium sulfate in an amount of 100-500 ppm by weight.

In particular, the composition may comprise approximately 15% of a concentrate essentially consisting of hydrogen peroxide in a concentration of 49-51% by volume, colloidal silver in an amount of 490-510 ppm by weight, phosphoric acid in an amount of of 400-500 ppm by weight, sodium nitrate in an amount of 250-300 ppm by weight, gum arabic in an amount of 20-25 ppm by weight, and water (preferably deionized, ultrafiltered or treated by reverse osmosis), the water preferably having a conductivity of less than or equal to 0.1 μ8/ϋπι (microsiemens per centimeter).

In particular, the composition may comprise 5-25%, preferably approximately 15% of the concentrate obtainable from Example 1 of PCT/CH 2009/000234 filed July 3, 2009.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described in the following with reference to the drawing, which is for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawing, Fig. 1 shows a diagram illustrating the bactericidal action of the composition according to the present invention and of several controls.

DESCRIPTION OF PREFERRED EMBODIMENTS

Example 1 : Preparation of a disinfecting detergent composition containing silver nitrate

An aqueous disinfectant comprising hydrogen peroxide and silver nitrate was prepared according to Example III of US 4,915,955, whose contents are incorporated herein in their entirety by reference for teaching the preparation of aqueous disinfectants containing hydrogen peroxide and a silver component. This disinfectant is available commercially from Sanosil AG, Hombrechtikon, Switzerland under the brand name "Sanosil Super 25".

15 liters of the disinfectant were mixed at room temperature under red light with deionized water (conductivity max. 0.1 μ8/αη) to a total of 100 liters. Surfactants were added as follows and stirred until a clear solution was obtained:

0.5 liters of Genapol X-050™;

3.0 liters of Genapol X-080™;

0.5 liters of Genapol UD- 1 10™; and

- 1.0 liters of Hostapur SAS-30™ (a 30% solution of anionic surfactant in water).

The resulting concentrated detergent composition contained:

hydrogen peroxide in an amount of approximately 7.5% by volume;

silver nitrate in an amount to yield approximately 150 ppm Ag by weight;

- phosphoric acid in an amount of approximately 1 10 ppm by weight;

isotridecyl polyglycol ether with a mean ethylene oxide content of 5 mol/mol in an amount of approximately 0.5% by weight;

isotridecyl polyglycol ether with a mean ethylene oxide content of 8 mol/mol in an amount of approximately 3% by weight;

- Cj i-oxo alcohol polyglycol ether with a mean ethylene oxide content of 1 1 mol/mol in an amount of approximately 0.5% by weight; and

sodium Ci4-Ci₇ secondary alkyl sulphonate in an amount of approximately 0.3% by weight. The total content in surfactants was approximately 4.3% by weight. This concentrated composition is ready to be used in cleaning applications where a strong cleaning effect is required, e.g. for surface cleaning applications with strong dirt layers. The concentrated composition is storage stable, with a decomposition of hydrogen peroxide of less than 5% over two years at ambient temperature (5-25 °C).

The concentrated composition may be further diluted. A first diluted composition was obtained by diluting the concentrated composition with deionized water to a concentration of 20% by volume, i.e. to a hydrogen peroxide content of approximately 1.5% by volume, a silver ion content of approximately 30 ppm, and a total surfactant content of approximately 0.9% by weight. This diluted product will in the following be referred to as sample D. A second diluted composition was obtained by diluting the concentrated composition with deionized water to a concentration of 1% by volume.

Example 2: Preparation of a disinfecting detergent composition containing colloidal silver A concentrate for an aqueous disinfectant was prepared according to Example 1 of PCT/CH 2009/000234 filed July 3, 2009, whose contents are incorporated herein in their entirety by reference for teaching the preparation of aqueous disinfectants containing hydrogen peroxide and colloidal silver. For preparing the concentrate, 50 grams of a stabilizer (gum arabic "quick-gum type 8074", purified and standardized, E414 / CAS 9000-01-05; Alfred L. Wolff, D-Hamburg) were dissolved in 950 ml of deionized water (conductivity at or below 0.1 μ8/αη) at 55 °C; the mixture was filled into an agitator (stainless steel V2A or V4A, slow-running horseshoe mixer, heating and cooling facilities, pressure controllable up to 3 bar; passivated before use) and stirred for approximately 15 minutes. 400 ml of phosphoric acid (CAS 7664-38-2, 85%, purum; Fluka Chemie, CH-Buchs) were slowly added, yielding a pH of 1.2, and the resulting mixture was stirred for 30 minutes while the temperature was reduced to 50 °C. 600 ml of an aqueous solution of sodium nitrate (CAS 7631-99-4, ultra pure; Fluka Chemie, CH-Buchs) were slowly added, and the resulting mixture was stirred during 30 minutes. 10Ό00 ml of aqueous colloidal silver (Argentum colloidale, CAS 7440-22-4, 120 g/1 in purified water; Johnson Matthey, CH-Zurich) was added in portions, the pressure was increased to 2 bar, and the mixture was stirred for 120 minutes. The temperature was lowered to 30 °C. The resulting storage-stable intermediate product (12 liters) was filled into standard containers made from HDPE (high-density polyethylene).

2'388 liters of aqueous hydrogen peroxide solution (CAS 7722-84-1, 49.0-49.9%, purum, Solvay, BE-Bruxelles) were filled into an agitator made from stainless steel V2A or V4A (resistant to hydrogen peroxide, sealable with pressure relief valve, passivated before use). 12 liters of the intermediate product were added in portions, and the resulting mixture was stirred for four hours. 2'400 liters of concentrate were thus obtained. The concentrate was filled into standard containers with pressure relieve valves.

The concentrate essentially consisted of:

hydrogen peroxide in an amount of approximately 49% by volume;

colloidal silver in an amount of approximately 500 ppm by weight;

gum arabic in an amount of approximately 21 ppm by weight;

phosphoric acid in an amount of approximately 140 ppm by weight;

sodium nitrate in an amount of approximately 300 ppm by weight; and

deionized water to 100%.

15 liters of the concentrate were mixed at room temperature under red light with deionized water (conductivity max. 0.1 μ8/αιι) to a total of 100 liters. Surfactants were added as follows and stirred until a clear solution was obtained:

0.5 liters of Genapol X-050™;

3.0 liters of Genapol X-080™;

0.5 liters of Genapol UD-1 10™; and

1.0 liters of Hostapur SAS-30™.

The resulting concentrated detergent composition contained:

hydrogen peroxide in an amount of approximately 7.5% by volume;

colloidal silver in an amount of approximately 75 ppm by weight; gum arabic in an amount of approximately 3 ppm by weight;

phosphoric acid in an amount of approximately 21 ppm by weight;

sodium nitrate in an amount of approximately 45 ppm by weight;

C] i-oxo alcohol polyglycol ether with a mean ethylene oxide content of 1 1 mol/mol in an amount of approximately 0.5% by weight; and

- sodium C₁₄-C₁ secondary alkyl sulphonate in an amount of approximately 0.3% by weight.

The total content in surfactants was approximately 4.3% by weight. Also this concentrated composition is ready to be used in cleaning applications where a strong cleaning effect is required. The concentrated composition is storage stable at least over a time of two years at ambient temperature with less than 5% decomposition of hydrogen peroxide (see Example 6 below).

A diluted product was obtained by diluting the concentrated composition with water to a concentration of 20% by volume, i.e. to a hydrogen peroxide content of approximately 1.5% by volume, a silver content of approximately 15 ppm by weight, and a total surfactant content of approximately 0.9% by weight.

Example 3: Health/environment tests

The concentrated compositions of Examples 1 and 2 were tested against requirements of health and environmental authorities, including the health requirements of the Swiss Health Authority (Bundesamt fur Gesundheit), international toxicity classifications (no toxicity classification required), Swiss waste-water laws, and biodegradability according to OECD standard No. 302B. All requirements were fully met.

Example 4A: Bactericidal tests at 20% concentration The bactericidal properties of the first diluted product of Example 1 (sample D) were tested as follows. 10 ml of sample D were contaminated with E. coli (ATTC 8739) at an initial germ count of 9.27 x 10⁶/ml. The mixture was kept at 37 °C for 30 minutes. The germ count was determined after 1, 2, 3, 4, 5, 6 and 30 minutes. Controls were carried out in the same manner. Controls are given in Table 1 (samples A-C and E-F).

Table 1 : Samples for tests of bactericidal activity

The results are shown in Figure 1. The NaCl control, sample F, exhibited a largely constant germ count over 30 minutes. If surfactants only were used, sample E, the germ count rapidly fell within one minute to approximately 40% of the original germ count and started to rise slowly again to approximately 50% of the original germ count. This is believed to be a result of the relatively mild action of the prevalently nonionic surfactants used in the compositions of the present invention, which alone are much less potent germicides than most cationic surfactants and cannot stop the bacteria from reproducing. If the surfactants were combined with hydrogen peroxide, sample A, the germ count fell within the first minute to a similar level as for the surfactants alone. The germ count further decreased during the next four minutes to approximately 15% of the original germ count. Thereafter, the germ count further decreased towards zero within the next 25 minutes. Hydrogen peroxide alone, sample B, exhibited a very similar behavior, except that the initial decrease in germ count was slower. The behavior of sample A, i.e. of the combination of hydrogen peroxide with surfactants, may therefore be understood as an additive superposition of the actions of hydrogen peroxide (sample A) and of the surfactants (sample E). The initial rapid decrease in germ count may be attributed to the surfactants, while the slower decrease thereafter may be attributed to the hydrogen peroxide. There are no indications of a synergistic effect between hydrogen peroxide and surfactants in the absence of the silver component.

The combination of hydrogen peroxide and the silver component, sample C, resulted in a rapid decrease in germ count over the first minute to about 20% of the original germ count, followed by a slower decrease to almost zero over the next four minutes. In this sense, the combination of hydrogen peroxide and the silver component proved to be more effective than the combination of hydrogen peroxide and surfactants. The best results, however, were achieved with the diluted product of the present invention, sample D. Already after one minute the germ count was below the detection limit. This extremely rapid action and high efficacy was unexpected in view of the results from samples A-C and E. If the action of sample D were purely an additive superposition of the actions of the components alone, a slower decrease in germ count would be expected.

These results prove an unexpected synergistic effect between the three main components of the composition of the present invention, i.e., between hydrogen peroxide, the silver component, and the surfactants. Example 4B: Bactericidal tests at 1% concentration

Further bactericidal tests were carried out as follows. Bactericidal efficiency was tested by quantitative methods proposed by Deutsche Gesellschaft fur Hygiene und Mikrobiologie (DGHM) according to their guidelines for testing chemical methods of disinfection. Bactericidal efficiency was indicated by the RF value, which represents the order of magnitude by which the agent is able to reduce the number of germs in a microbe suspension under the conditions tested. An RF value of 5 is considered acceptable by DGHM. During the tests, conditions were chosen that mimick the environment of typical industrial applications. Particular contaminations, such as proteins, fat, remainders of other detergents etc., which might reduce the bactericidal activity in the proposed fields of application, were modeled. Water hardness was also taken into consideration.

An inactivating mixture "In-Fo" was prepared as follows: 0.85% NaCl; 0.1% tripcasine; 3.0% polysorbate-80; 0.3% lecitihin; 0.1% histidine; 0.5% Na-thiosulphate in water.

Organic matter load was modeled with high-fat milk having 6% to 20% milk fat concentration.

The number of cells was determined by spreading on agar plates and by counting the cells still alive by colony forming.

Suspensions of microbe cultures were prepared according to DGHM specifications. Concentrations were set in sterile water at standard hardness. 0.1 ml of microbe suspension were added to 10 ml of test solution and stirred. At specified temperatures and exposure times, a volume of 1 ml was removed from each sample and pipetted into the 9 ml of inactivating mixture In-Fo. After 10 minutes, dilution series were formed from the mixtures, and the number of cells that had survived were determined. For verification, sterile hard water was used instead of disinfectant. The tests were carried out at ambient temperature.

The following microorganisms were tested (HNCMB = Hungarian national collection of medical bacteria):

Staphylococcus aureus (S. aureus) HNCMB 1 10003

Pseudomonas aeruginosa (P. aeruginosa) HNCMB 170001

Escherichia coli (E. coli) HNCMB 33001

Streptococcus faecium (S. faecium) HNCMB 80177

Candida albicans (C. albicans) OKI Mycological Dept.

Tests were carried out at ambient temperature at an exposure time of 30 minutes, at medium protein load, using the second diluted product of Example 1 (1% by volume of the concentrated detergent composition diluted in water, corresponding to a hydrogen peroxide content of approximately 0.075% by volume).

The tests indicated high germicidal efficiency against all of the tested bacteria, the RF value reaching or exceeding RF 5, while fungicidal activity was somewhat lower. Further tests were carried out as before, but with increased protein load, with similar results. These results indicate a surprisingly high bactericidal activity already at very low concentrations of the active ingredients of the compositions. This again indicates an unexpected synergistic effect between the ingredients of the composition.

Fungicidal activity was additionally tested with the first diluted product of Example 1 (20% by volume of the concentrated detergent composition diluted in water) at high protein load. Fungicidal activity proved to be excellent (RF > 5) under these conditions. Example 5: Cleaning action

The cleaning action of the concentrated composition and of the 20% diluted product of Examples 1 and 2 was tested on various surfaces, including glass, steel, ceramics, chromium-nickel steel, plastics and wood, against a variety of contaminants, including natural fats, glycerin, petroleum jelly (Vaseline), tallow, inorganic and organic lubricants, blood, synthetic fats, paraffin and fatty acids. The concentrated compositions as well as the diluted products exhibited excellent cleaning properties on all surfaces over the full spectrum of contaminants, without any negative effects on the surfaces. Example 6: Stability tests

Both the concentrated detergent composition of Example 2 (initial hydrogen peroxide content 7.5% by volume) and the diluted composition of Example 2 (20% by volume of concentrated detergent composition in deionized water at a conductivity below 0.1 μ8/ΰΐη, initial hydrogen peroxide content 1.5% by volume) were subjected to long-time stability tests over a period of 24 months, in three different temperature ranges. Two batches of each the concentrated composition and the 20% diluted composition were tested. Results are given in Tables 2 (concentrated composition) and Table 3 (20% diluted composition). Table 2: Long-time stability tests, concentrate - hydrogen peroxide content in percent by volume

Table 3: Long-time stability tests, 20% diluted product - hydrogen peroxide content percent by volume

The concentrated product exhibited a hydrogen peroxide decomposition of less than 2% after 12 months and less than 5% after 24 months at temperatures between 5 and 25 °C. The 20% diluted product lost 7% of its hydrogen peroxide content after 12 months and 20% of the hydrogen peroxide content after 24 months at temperatures between 5 and 25 °C. These results indicate an extraordinary stability of both the concentrate and the 20% diluted product.

Claims

A detergent composition comprising the following components:

hydrogen peroxide in an amount of 1-15% by weight;

at least one silver component selected from the group consisting of silver salts and colloidal silver in an amount to yield 30-300 ppm Ag by weight;

at least one nonionic surfactant, the nonionic surfactant being a C₈-C₁₈ alkyl polyglycol ether with a mean ethylene oxide content of 3-15 mol/mol, the nonionic surfactant being present in an amount above the critical micelle concentration of the nonionic surfactant in the composition; and

at least one anionic surfactant, the anionic surfactant being a Ci₂-C_!8 secondary alkyl sulphonate in an amount above the critical micelle concentration of the anionic surfactant in the composition.

The composition of claim 1, wherein the surfactants are present in an amount effective to provide the composition with an anti-microbial activity that is higher than an anti-microbial activity of the composition in absence of the surfactants.

The composition according to any of the preceding claims, wherein the amount of nonionic surfactant is at least five times the amount of anionic surfactant.

The composition according to any of the preceding claims, wherein the at least one nonionic surfactant is a Cio-Ci₄ alkyl polyglycol ether with a mean ethylene oxide content of 3-15 mol/mol.

The composition according to any of the preceding claims, wherein the at least one nonionic surfactant is selected from the group consisting of:

Ci i-oxo alcohol polyglycol ethers with a mean ethylene oxide content of 10- 12 mol/mol.

6. The composition according to any of the preceding claims, wherein the composition comprises at least a first and a second nonionic surfactant, the first nonionic surfactant being an isotridecyl polyglycoi ether with a mean ethylene oxide content of 3-10 mol/mol, and the second nonionic surfactant being a Cn- oxo alcohol polyglycoi ether with a mean ethylene oxide content of 10-12 mol/mol.

7. The composition according to any of claims 1-5, wherein the composition comprises at least a first, a second and a third nonionic surfactant, the first nonionic surfactant being an isotridecyl polyglycoi ether with a mean ethylene oxide content of 7-9 mol/mol, the second nonionic surfactant being an isotridecyl polyglycoi ether with a mean ethylene oxide content of 4-6 mol/mol, and the third nonionic surfactant being a Cn-oxo alcohol polyglycoi ether with a mean ethylene oxide content of 10-12 mol/mol.

8. The composition of any of the preceding claims, wherein the anionic surfactant is a sodium Cn-Cn secondary alkyl sulphonate.

9. The composition of any of the preceding claims, the composition being essentially free of cationic surfactants and/or lactic acid.

10. The composition of any of the preceding claims, wherein the silver component is selected from the group consisting of silver nitrate, silver sulphate, silver chloride, sodium/silver chloride complex, silver benzoate, silver carbonate, silver fluoride, silver (I) oxide and silver (II) oxide.

1 1. The composition of any of claims 1 to 9, wherein the silver component is colloidal silver.

12. The composition of claim 1 1, the composition further comprising at least one sodium salt selected from the group consisting of sodium nitrate, sodium sulphate and sodium phosphate, the sodium salt being present in an amount of 5-125 ppm by weight.

13. The composition of claim 11 or 12, the composition being essentially free of any polyhydroyxl monocarboxylic acids.

14. The composition of any of the preceding claims, further comprising at least one of the following:

an inorganic acid selected from the group consisting of phosphoric acid, nitric acid, sulphuric acid, boric acid, and hydrochloric acid, the inorganic acid being present in an amount to adjust the pH of the composition to below 3; and a stabilizer comprising at least one biopolymer in an amount of at least 1 ppm by weight.

15. A detergent product comprising the detergent composition according to any of the preceding claims in an amount of 5-100% by weight and water in an amount of 0- 95% by weight.