Patent Application
20240164375
The present invention generally relates to a novel liquid disinfectant composition particularly useful in the industrial sector and especially in the agro-food industry, as well as in the field of catering and institutional kitchens, livestock hygiene and consumer disinfectant products. A particular object of the invention is a composition which has good physical stability, in concentrated form, and offers high disinfectant efficacy when in diluted form in water. The invention has application, in particular, in clean conditions (disinfectant) or in dirty conditions (detergent/disinfectant), for disinfecting open surfaces, disinfection in washing tunnels and automatic systems, and disinfection by circulation, in particular in so-called clean-in-place systems (CIP).
The main disinfectants currently used in the industrial sector have advantages overall, but also have disadvantages (see table below), such that manufacturers are constantly looking for novel disinfectant compositions there are capable of responding to the increasingly numerous requirements that it is difficult to satisfy simultaneously.
In this context, the present invention aims to solve the technical problem consisting of providing a novel liquid acid disinfectant composition simultaneously having:
In order to develop a disinfectant composition having a reduced environmental impact, the inventors turned to the use of active substances based on organic acids of natural origin, and more particularly a combination of at least one aliphatic fatty acid having 8 to 12 carbon atoms, in particular octanoic acid, and glycolic acid.
These relatively short chain organic acids have a satisfactory environmental profile and therefore offer an interesting alternative to disinfectant products which are known for their high environmental impact.
Hence, a family of biocidal products is currently on the market, which are intended in particular for disinfecting surfaces in contact with foodstuffs and animal feeds, and marketed by SOPURA under the name “SOPURCLEAN”, comprising a mixture of octanoic acid and decanoic acid, in combination with various acids such as strong mineral acids (sulfuric, nitric, phosphoric), lactic acid, glycolic acid or citric acid.
The main difficulty linked to the use of relatively short chain organic acids rests in the formulation of a stable composition in the concentrated state, and obtaining a composition that is easy to apply, after dilution, while retaining its disinfectant efficacy.
Indeed these acids have the property of being particularly hydrophobic, and it is extremely difficult to formulate them in the form of a concentrated product, in particular when this must contain (for reasons of cost) a high amount of water that can be as much as approximately 70% by mass.
It has been discovered, and this constitutes the basis of the present invention, that it was possible to solve the technical problem stated above and to achieve the set of desired properties by using precisely chosen components and, in particular, a specific solubilising or hydrotropic system combining an ethoxylated fatty alcohol and a copolymer of polypropylene glycol and polyethylene glycol which will be defined below.
A first object of the invention relates to a liquid disinfectant composition in concentrated or diluted form, characterised in that it comprises:
in which x represents an integer between 2 and 15, y represents an integer between 15 and 35, and z represents an integer between 2 and 15; or a mixture of such copolymers,
A second object of the invention concerns the use of such a composition as described above for disinfecting open surfaces or for disinfecting washing tunnels or circuits.
A third object of the invention concerns a method for disinfecting open surfaces or disinfecting washing tunnels or circuits by applying a composition according to the invention.
In the context of the present invention:
Active Substances
According to the invention, organic acid disinfectants of natural origin are used as active substances and in particular a mixture comprising, and preferably consisting of:
An aliphatic-chain fatty acid having 8 to 12 carbon atoms is, in particular, a monocarboxylic acid with straight or branched alkyl chain, preferably a straight chain, having 8 to 12 carbon atoms. Such an acid can be chosen from the group consisting of octanoic acid, nonanoic acid, decanoic acid, preferably from octanoic acid and decanoic acid and will more preferably be octanoic acid (also named caprylic acid).
When the composition is in concentrated form, this fatty acid or the mixture of such acids can represent between 1 and 10% by mass of the mass of the composition, preferably between 1 and 5%, more preferably between 2 and 5%.
When said composition is in diluted form, the aliphatic-chain fatty acid having 8 to 12 carbon atoms or the mixture of such acids represents between 0.02 and 0.2% by mass of the mass of the composition, preferably between 0.02% and 0.1%, more preferably between 0.04 and 0.1%.
Glycolic acid is preferably used alone, but it can also be used in mixture with acetic acid in ratios by mass varying from 4:1 to 2:1.
When the composition is in concentrated form, glycolic acid, optionally in mixture with acetic acid, represents between 0.5% and 20% by mass of the mass of the composition, preferably between 0.5% and 15%, more preferably between 0.5% and 10%, and still more preferably between 0.5% and 2%.
When said composition is in diluted form, glycolic acid, optionally in mixture with acetic acid, represents between 0.01% and 0.40% by mass of the mass of the composition, preferably between 0.01% and 0.30%, more preferably between 0.01% and 0.20%, and still more preferably between 0.01% and 0.04%.
The two components forming the active substances of the composition according to the invention can be used in varied relative proportions. Advantageously, the mass ratio between the aliphatic-chain fatty acid having 8 to 12 carbon atoms or the mixture of such acids and glycolic acid, optionally in mixture with acetic acid, is between 20/1 and 5/1, preferably between 15/1 and 5/1, more preferably between 10/1 and 5/1.
The pH-Regulating Acid System
The active substances chosen in the context of the invention have an optimum efficacy when the composition is in the diluted state, which depends on the pH and the pathogen to be eliminated.
For this reason, these active substances should be combined within the composition according to the invention with a pH-regulating acid system, the type and amount of which are chosen such that the composition, in its diluted form, has a pH lower than the value of the pH for optimum efficacy, generally lower than 3.8, preferably lower than 2.0. This pH-regulating acid system is advantageously chosen from the group consisting of methane sulfonic acid, phosphoric acid, sulfuric acid, sulfamic acid and the mixtures thereof.
In order to further reduce the environmental impact of the composition according to the invention, this acid system advantageously consists of methane sulfonic acid. This acid, being nitrogen-free and phosphorus-free, has an excellent environmental profile and also possesses very good detergent and descaling properties.
In general:
In the case where the pH-regulating acid system consists of methane sulfonic acid, it has been determined that this acid must preferably be used in an amount between 5 and 30%, preferably between 7.5 and 20%, more preferably between 10 and 15%, still more preferably between 10.5 and 12%, of active material within the composition in its concentrated form. Hence, it has been observed that for a concentration of this acid less than 5%, the composition did not guarantee optimum efficacy of the organic acids against the pathogens, in its diluted form. In order to obtain optimum efficacy of the organic acids used, in particular against yeasts, it is, notably, necessary to guarantee a pH lower than approximately 2.0 on dilution.
Solubilising System
In order to solve the technical problems described above and linked to the use of relatively short chain organic acids which are particularly hydrophobic and consequently extremely difficult to formulate cold in the form of a concentrated product, the inventors have discovered and implemented an original solubilising system comprising an ethoxylated fatty alcohol, or a mixture of such ethoxylated fatty alcohols and a PEG-PPG copolymer as defined above. Advantageously, this solubilising system consists of, for at least 99% by weight, and preferably 100% by weight, an ethoxylated fatty alcohol, or a mixture of such ethoxylated fatty alcohols and a PEG-PPG copolymer as defined above.
The ethoxylated fatty alcohols that can be used in the context of the invention, alone or in a mixture, satisfy the formula R—(O—C2H4)n—OH in which R represents a linear or branched alkyl group having 6 to 12 carbon atoms and n represents an integer between 4 and 8.
Examples of such fatty alcohols include, in particular, ethoxylated hexane-1-ol ethoxylated octane-1-ol and ethoxylated decanol-1-ol.
When the composition is in concentrated form, the ethoxylated alcohol or the mixture of ethoxylated alcohols represents between 1 and 30% by mass of the mass of the composition, preferably between 1% and 20%, more preferably between 1 and 15% and still more preferably between 4 and 8%.
When said composition is in diluted form, the ethoxylated alcohol or the mixture of ethoxylated alcohols represents between 0.02 and 0.6% by mass of the mass of the composition, preferably between 0.02% and 0.4%, more preferably between 0.02 and 0.3% and still more preferably between 0.08 and 0.16%.
According to a currently preferred embodiment, an ethoxylated hexane-1-ol is used as the ethoxylated fatty alcohols, preferably the compound having the CAS number: 31726-34-8, and having a chain length of 6 carbon atoms, and an ethoxylation number equal to 5. Such a product is, for example, the product marketed under the name Lutensol CS 6250® by BASF, Rokanol H5® by PCC EXOL or Novel 6-6 Ethoxylate by SASOL.
It has been observed that this molecule, which has good emulsifying and detergent properties, not only participates in the solubilisation of the fatty acid but also ensures good stability of the composition when cold, in the concentrated state.
The second component of the solubilising system used according to the invention is a copolymer, the central part of which is composed of a polypropylene glycol (PPG) group surrounded by two polyethylene glycol (PEG) groups and responding to the formula:
in which x represents an integer between 2 and 15, y represents an integer between 15 and 35, and z represents an integer between 2 and 15; or a mixture of such copolymers.
These copolymers (INCI name Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)) are generally used for their anti-foaming properties.
Preferably, in the context of the invention, copolymers are chosen for which the molar mass of the poly(propylene glycol) central block is between 870 and 2030, preferably between 1000 and 1800, more preferably between 1100 and 1750; and for which the percentage of poly(ethylene glycol) in the molecule is between 10 and 40%.
Entirely unexpectedly, it was discovered that these copolymers potentiate the solubilisation properties exerted by the ethoxylated fatty alcohols, not only within compositions intended to be applied under conditions where the foam must be controlled, but also in compositions intended to be applied under conditions requiring the formation of foams.
In general, these copolymers can be used in various proportions. A person skilled in the art will determine, in each particular case, the concentrations (mass/mass) making it possible to obtain compositions that are clear and stable on dilution.
Advantageously, when said composition is in concentrated form, the above-mentioned copolymer or the mixture of copolymers represents between 2 and 40% by mass of the mass of the composition, preferably between 2 and 30%, more preferably between 2 and 20% and still more preferably between 3 and 8%.
Advantageously, when said composition is in diluted form, the above-mentioned copolymer or the mixture of copolymers represents between 0.04 and 0.8% by mass of the mass of the composition, preferably between 0.04 and 0.6%, more preferably between 0.04 and 0.4% and still more preferably between 0.06 and 0.16%.
Examples of preferred copolymers may include, in particular, the products marketed under the commercial names, Pluronic PE 4300®, Pluronic PE 6100®, Pluronic PE 6200®, Pluronic PE 6400® by BASF, Genapol PF 10®, Genapol PF20® by Clariant, TB 6010®, TB 5031® by Ineos, Dowfax 63N10® by DOW, and Rokamer 2000® by PCC Exol.
The two components forming the solubilisation system of the composition according to the invention can be used in various relative proportions.
Advantageously, the mass ratio between the ethoxylated alcohol or the mixture of ethoxylated alcohols and the above-mentioned copolymer or the mixture of copolymers is between 5/1 and 1/5, preferably between 4/1 and 1/4, more preferably between 2/1 and 1/2.
Surfactant(s)
The choice of surfactants present in the compositions according to the invention varies, of course, according to the intended application.
Hence, in the case of use on an open surface, it is necessary to formulate a product having foaming properties which enable the application of the product for this type of use. Similarly, in the case of use in a washing tunnel or circuit, it will be necessary by contrast to obtain a control of the foam in order to obtain a weakly-foaming or non-foaming product.
In an original and advantageous manner, it has been shown that suitably chosen surfactant systems make it possible to formulate compositions intended for very different applications, while retaining the set of other constituents which have been described above.
According to a particular embodiment, a composition according to the invention intended for disinfecting open surfaces requiring the formation of foam can advantageously comprise a mixture of surfactants consisting of:
in which R represents an alkyl group having 12 to 16 carbon atoms, and n represents an integer between 2 and 12, preferably between 8 and 10, more preferably 10; or a mixture of such surfactants.
Examples of preferred, non-ionic, foaming surfactants include, in particular, cocamine oxide, such as, in particular, the products marketed under the names Oxydet DMCLD® by Kao, Genaminox 12 R® by Clariant, and Euroxyde LO/A® by EOC surfactant. Also included is myristamine oxide, such as, in particular, the products marketed under the names Kapanox MO® by Stepan and Flavol AOM® by Enaspol.
In general, this foaming non-ionic surfactant or this mixture of foaming surfactants will be used in various proportions in the compositions according to the invention intended for disinfecting open surfaces.
Hence, when the composition is in concentrated form, this surfactant or mixture of surfactants represents between 1 and 20% by mass of the mass of the composition, preferably between 1% and 15%, more preferably between 1 and 10% and still more preferably between 1 and 5%; and when said composition is in diluted form, this surfactant or mixture of surfactants represents between 0.02 and 0.4% by mass of the mass of the composition, preferably between 0.02% and 0.03%, more preferably between 0.02 and 0.2% and still more preferably between 0.02% and 0.1%.
Excellent results have been obtained by using, as foaming non-ionic surfactant, an alkyl amine oxide and, more particularly, dodecyldimethylamine oxide (CAS number: 308062-28-4), advantageously in an amount between 1 and 5% by mass of the mass of the composition in concentrated form.
This molecule is particularly appreciated for its good biodegradability, its high foaming power and the formation of a stable foam, its detergent and wetting properties and its good compatibility with other surfactants.
Examples of preferred anionic surfactants include, in particular, alkyl ether carboxylic acid, such as laureth-11 carboxylic acid (CAS number 27306-90-7), in particular the products marketed under the names Akypo RLM100® by Kao, and Empicol CBJ® by Innospec. Also included is laureth-6 carboxylic acid (CAS number 27306-90-7), in particular the products marketed under the name Akypo RLM 45® by Kao.
In general, the anionic surfactant or the mixture of anionic surfactants will be used in various proportions in the compositions according to the invention intended for disinfecting open surfaces.
Hence, when the composition is in concentrated form, this surfactant or mixture of surfactants represents between 1 and 30% by mass of the mass of the composition, preferably between 1% and 20%, more preferably between 1 and 10% and still more preferably between 1 and 5%; and when said composition is in diluted form, this surfactant or mixture of surfactants represents between 0.02 and 0.6% by mass of the mass of the composition, preferably between 0.02% and 0.4%, more preferably between 0.02 and 0.2% and still more preferably between 0.02% and 0.1%.
Excellent results have been obtained by using, as anionic surfactant, a carboxylic acid ether and more particularly the compound known under the INCI name Laureth-11 Carboxylic acid (CAS number: 27306-90-7), having a chain length of 12 atoms and a degree of ethoxylation of 10, advantageously in an amount between 1 and 5% by mass of the mass of the composition in concentrated form. This molecule is particularly interesting insofar as it has an excellent foaming property, with formation of a thick and stable foam, good biodegradability and an ecologically significant low value of aquatic toxicity.
In general, in such a composition intended for disinfecting open surfaces, the mass ratio between the foaming non-ionic surfactant or the mixture of such surfactants and the anionic surfactant, is between 20/1 and 1/1, preferably between 15/1 and 1/1, more preferably between 10/1 and 1/1.
According to another particular embodiment, a composition according to the invention intended for disinfecting washing tunnels or circuits requiring a control of the foam can advantageously comprise a weakly-foaming non-ionic surfactant or a mixture of such surfactants.
Examples of preferred weakly-foaming non-ionic surfactant can include, in particular, decyldimethylamine oxide (CAS number: 2605-79-0), such as, in particular, the products marketed under the names Tegotens DO® by Evonik, Colalux C-10@ by Colonial chemicals, and Barlox 10S® by Lonza. Also included are octyldimethylamine oxide, such as, in particular, Colalux C-8® by Colonial Chemicals, Genaminox OC® by Clariant, and Barlox 8S® by Lonza.
In general, this weakly-foaming non-ionic surfactant or this mixture of such surfactants will be used in varied proportions in the compositions according to the invention intended for disinfecting washing tunnels or circuits.
Hence, when the composition is in concentrated form, this surfactant or mixture of surfactants represents between 1 and 20% by mass of the mass of the composition, preferably between 1% and 15%, more preferably between 1 and 10%, and still more preferably between 1 and 5%; and when said composition is in diluted form, this surfactant or mixture of surfactants represents between 0.02 and 0.4% by mass of the mass of the composition, preferably between 0.02% and 0.3%, more preferably between 0.02 and 0.2% and still more preferably between 0.02 and 0.1%.
Excellent results have been obtained by using, as non-ionic surfactant, decyldimethylamine oxide (CAS number: 2605-79-0), advantageously in an amount between 1 and 5% by mass of the mass of the composition in concentrated form.
The main property of this molecule is that of being weakly foaming, but it also has good stability in an acid medium and good biodegradability.
The majority element from the quantitative point of view in the compositions according to the invention is of course water, including when these compositions are in concentrated form.
For this water, it is possible to use, for example, purified water such as distilled water, demineralised water, mains water or even industrial water.
When the composition is in concentrated form, water represents between 40 and 85% by mass of the mass of the composition, preferably between 50% and 80%, more preferably between 60 and 80% and still more preferably between 65 and 75%.
When said composition is in diluted form, water represents between 98.8% and 99.7% by mass of the mass of the composition, preferably between 99.0% and 99.6%, more preferably between 99.2 and 99.6%.
In general, the compositions in concentrated form are used after dilution to the necessary concentration (V/V) to enable a satisfactory application of the concentrated composition. The term “satisfactory application” shall mean the necessary dilution of the concentrated form, for which the desired microbiological efficacy is obtained for an open surface or closed circuit use.
According to a preferred embodiment, the compositions of the invention comprise, in concentrated form:
Method for Preparing Compositions According to the Invention
The compositions according to the invention, which have just been described, can be prepared by conventional methods, on the industrial scale, for preparation of concentrated liquid disinfectant compositions, for example by mixing various compounds until a homogeneous mixture is obtained.
Advantageously, these compositions will be able to be prepared in a mixing reactor by implementing the following steps:
The following components, taken in the quantities mentioned, were mixed according to the describe protocol in compliance with the following table:
The concentrated product thus obtained has the following composition:
By following the experimental protocol described in Example 1, the concentrated
product was prepared having the composition described in the table below.
In their applications, these compositions will be used after dilution to concentrations between 0.5 and 3.0%, i.e. between 5 and 30 g/L for an open surface or closed circuit use. The degree of dilution will depend on the material used and the concentration (V/V) of active ingredients necessary in order to obtain a satisfactory result from a microbiological point of view.
Demonstrating the microbiological efficacy of the compositions according to the invention.
The microbiological efficacy of the compositions according to the invention has been demonstrated by following the experimental protocols defined according to the following standards:
Candida
Albicans
Candida
Albicans
Staphylococcus
aureus
Staphylococcuss
aureus
Enterococcus
hirae
Enterococcus
hirae
Pseudomonas
aeruginosa
Pseudomonas
aeruginosa
Escherichia
coli
Escherichia
coli
Salmonella
Listeria
Salmonella
Listeria
Staphylococcus
aureus
Enterococcus
hirae
Pseudomonas
aeruginosa
Escherichia
coli
Candida
albicans
These results show that the composition of Example 1 has a bactericidal efficacy for a concentration of 0.5% (V/V) and a contact time of 15 minutes, at temperature 20° C., as well as a yeasticidal efficacy for a concentration of 2.0% (V/V) and a contact time of 15 minutes, at temperature 20° C.
In general, the compositions according to the invention have a bactericidal and yeasticidal efficacy for a concentration greater than or equal to 2% (V/V).
Demonstrating the influence of the pH on the efficacy of the compositions according to the invention
In order to demonstrate the influence of the pH on the efficacy of the compositions according to the invention, various compositions were prepared by varying the concentration (m/m) of pH regulator in the concentrated composition.
The following compositions have therefore been tested:
2%
2%
12%
12%
12%
3%
3%
These compositions were diluted in demineralised water at 20° C. The pH of the diluted solution thus obtained was measured for various dilutions, expressed as amount of dry matter of the concentrated composition in 1 L of diluted composition.
The results obtained are presented in the following tables:
The efficacy of these compositions was determined by implementing the following test:
The results obtained are reported in the following table, it being specified that a composition is considered to be effective when the observed reduction R is greater than 3.
1%
An improvement in the efficacy can be observed for the compositions for which the methane sulfonic acid content is higher in the formulation. This increase in the acidity content has the consequence of lowering the pH at the dilution of use.
Carboxylic acids such as octanoic acid are Brönsted acids. They react with water to give carboxylate ions and oxonium ions.
The reaction progresses extremely quickly to an equilibrium state. The position of this equilibrium is a function of the acidity constant Ka of the acid-base pair, which only depends on the type of pair and the temperature. The higher Ka, the greater the formation of oxonium ions.
The pKa of octanoic acid is 4.85 (25° C.). The reduction in pH on dilution, makes it possible to find the octanoic acid in its predominant acid form which, in the desired case, increases its disinfectant properties.
Hence, it has been shown that in order to obtain an optimum efficacy of the organic acids used, in particular against yeasts, it is, in particular, necessary to guarantee a pH lower than 2.0 on dilution.
Demonstrating the effect of the copolymer on the solubilisation of the aliphatic-chain fatty acid.
The effect of various copolymers on the solubilisation of the octanoic acid and octanoic acid has been evaluated.
The following copolymers have therefore been evaluated.
The results obtained are presented in the following tables.
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
3%
These results show the importance of the presence of the copolymer in the compositions according to the invention in order to ensure good solubilisation of the fatty acid, in this case, octanoic acid. The copolymer potentiates the solubilisation effect of the ethoxylated fatty alcohol.
Analogous results were obtained with decanoic acid, although in this case the amount of copolymer necessary to obtain good solubilisation is much higher.
It is therefore possible to solubilise fatty acids of different chain lengths with different types of copolymers, chosen in particular from the PLURONIC® range. A person skilled in the art will thus easily determine the amount and type of the copolymer to use, according to the type of fatty acid to be solubilised in the composition, but also as a function of the desired result according to the conditions of application of the invention.
Demonstrating the very low corrosive mass of the compositions according to the invention
The disinfectant compositions can be more or less corrosive in terms of the substrates on which they are applied and, in particular, those made of stainless steel or aluminium alloys that are usually found in the agro-food industry. This corrosion is manifest by a uniform dissolution of the metal surface in contact with the applied composition. It is generally evaluated by measurements of mass loss or thickness reduction of the metal at the surface of the substrate on which the composition is applied and expressed by a corrosion rate (mg or g per surface area and per time) or more often by a speed of corrosion (thickness reduction per unit time: mm/year).
In the case of a mass loss Δm during time Δt, the speed of corrosion Vcorr is expressed
by the relation:
The corrosiveness of a composition is determined according to the following evaluation grid;
The corrosiveness of the compositions according to the invention was therefore evaluated under the following experimental conditions:
The results obtained are presented in the following table:
These results show that the composition of Example 1 of the invention leads to a very weak corrosion of the stainless-steel alloys and aluminium alloys for a concentration (m/V) of 3%, which is higher than the usual conditions of use.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2102378 | Mar 2021 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2022/050445 | 3/11/2002 | WO | 11/10/2023 |
