Sanitization composition and method for sanitization- purification of surfaces and environments

Abstract

A sanitization composition is provided for sanitization- purification of surfaces and environments, comprising particles of titanium dioxide dispersed in water to form an aqueous colloidal dispersion and having pre-established dimensions, preferably in the anatase crystal form. A part of the titanium dioxide is doped, in particular with nitrogen. The composition further comprising at least one optical brightener which, struck by ultraviolet radiation, is able to re-emit visible light by fluorescence.

Description

TECHNICAL FIELD

[0001] The present invention relates to a sanitization composition and method for sanitization-purification of both internal and external surfaces and environments.STATE OF THE PRIOR ART

[0002] The sanitization of residential and work environments, and even more so in hospital and similar environments, is an increasingly felt need.

[0003] A clean environment with pure air in fact guarantees a better quality of life and better working conditions and, in the medical-hospital environment, better care conditions.

[0004] In general, numerous and different operations and activities are required, adapted to make certain environments sanitary, in particular by cleaning, disinfecting and / or disinfestation activities.

[0005] In particular, compositions or paints are known which can be applied on certain surfaces and which contain substances having a disinfectant, antimicrobial or similar effect. WO9623051 A1 discloses detergent compositions containing bactericidally and photooxidatively active titanium dioxide of particle size less than 100 nm.

[0006] However, the known compositions are not fully satisfactory, above all in terms of effectiveness, persistence of effectiveness, ease of use, versatility.OBJECT OF THE INVENTION

[0007] An object of the present invention is to provide a sanitization composition and method which are free from the drawbacks herein disclosed in the known art; in particular, it is an object of the invention to provide a sanitization composition and method which are fully effective in the function of the sanitization / purification of the environments in which they are used, thus producing multiple beneficial effects.

[0008] A further object of the invention is to provide a sanitization composition, and the respective method of use, which can be applied simply and quickly to various types of surfaces and substrates, thus maintaining its effectiveness over time.

[0009] The present invention therefore relates to a sanitization composition and to a sanitization method as defined in essential terms in the annexed claims 1 and 9, respectively, as well as, for the additional preferred characters, in the dependent claims.

[0010] The invention provides a sanitization composition and method that allow to purify the air and the environment, allowing in particular an effective and long-lasting sanitization effect of surfaces and environments.

[0011] The composition of the invention is applied in a simple and fast way to a plurality of different surfaces, such as walls, glass, coatings, furniture surfaces, sanitary fixtures, etc.

[0012] Once applied, the composition of the invention performs various beneficial actions and achieves a plurality of effects, such as for example: repellency to dirt and moisture (self-cleaning action); cleaned and disinfected surfaces; elimination of moulds, bacterial and viral agents, other microorganisms, avoiding furthermore that these are formed again (bacteriostatic action against mites, moulds, spores, animal allergens, bacteria, pollen, etc.); purifying action of the air, which becomes perfectly breathable and free from unpleasant odours (odour neutralizing action); abatement of polluting substances, in particular the so-called VOC (volatile organic compounds, which are eliminated up to 99.8 0), fine particulate matter (PM 2.5 - PM 10), ethanol, carbon monoxide, benzene, ethyl benzene, toluene, methanol, sulphur dioxide, polycondensed aromatic compounds, nitrogen oxides, acetaldehyde, formaldehyde, xylene, nicotine, ozone; reduction of allergic forms and related symptoms.

[0013] The composition of the invention does not affect in any way the surface on which it is applied, which remains perfectly intact and retains all of its original characteristics; the composition of the invention is also completely eco-compatible.

[0014] The composition of the invention can be used in a variety of environments: residential, work and medical-health, as well as outside, on the surfaces of buildings, monuments, etc.

[0015] The use of the composition of the invention in a domestic or residential environment and in the workplace in general allows a significant increase in the quality of life and working conditions, allowing to live and work in healthy and clean environments.

[0016] The advantages are particularly important in hospital and similar environments, where the possible presence of pathogens is very high and can represent a risk factor both for patients and for the medical and nursing staff working therein.

[0017] Thanks to the treatment according to the invention, a high and lasting bacterium-static nature of the surfaces and the surrounding environment is obtained in clinics, laboratories and medical studies: in fact, bacteria, viruses, fungi, protozoa and spores are definitively inhibited by means of a molecular decomposition process.

[0018] The abatement activity of polluting substances makes the composition useful also for external environments, for example if applied to surfaces of buildings and monuments, roofs, floorings, etc.

[0019] An additional advantage of the invention is cost savings: by applying the composition of the invention, it is possible to do without a large number of different products and chemical detergents used for daily cleaning, disinfecting and sanitizing operations.

[0020] The composition of the invention comprises only natural components and is free of compounds and chemical additives such as chlorine, ammonia, detergents, etc.

[0021] The composition of the invention in fact comprises two main components: titanium dioxide, whose "photosensitive" molecules exposed to UV rays and in contact with the humidity of the air allow the oxygen to react with the substances with which they come into contact, transforming the same in molecules of harmless mineral salts; and water (distilled).

[0022] The composition, once applied on a generic surface, is activated by photocatalysis, simply by light radiation (in particular, but not necessarily, UV radiation) in the presence of air.

[0023] Activation does not require high intensity of irradiation: in general, less than 300 lumens are sufficient to activate the composition, triggering the photocatalytic process. In essence, activation is guaranteed only by the ultraviolet fraction of solar radiation and does not require artificial radiation (which however, optionally, can also be carried out).

[0024] The composition can however also be activated in another way, for example with another type of electromagnetic radiation (UV radiation, light radiation in the visible field, etc.), by induction, etc.

[0025] The treatment of an environment does not involve any risk and waiting: the action and the beneficial effects of the invention are in fact almost instantaneous, and start when the surface on which the composition has been applied is exposed to UV light: a luminous intensity of at least 0.001 mW / cm 2< is already able to activate the elimination of odours and the reduction of VOCs; with a light intensity of at least 0.1 mW / cm 2< all anti-pollution, antibacterial and self-cleaning functions are activated.

[0026] The composition of the invention contains (or essentially consists of) an aqueous colloidal dispersion of titanium dioxide, with particles of titanium dioxide of pre-established dimensions dispersed in water.

[0027] In particular, the composition of the invention is characterized by the use of titanium dioxide (or titanium oxide (IV), TiO 2 ) of pre-established dimensions, which is activated by photocatalysis.

[0028] According to the invention, the titanium dioxide present in the aqueous dispersion is in the form of particles having dimensions ranging from 100 to 300 nm, preferably from 150 to 300 nm.

[0029] Preferably, the particles of titanium dioxide have a mean diameter, calculated as the Sauter mean diameter (SMD) or as volume mean diameter (VMD), ranging from 200 to 250 nm, more preferably from 210 to 220 nm.

[0030] A typical dimensional distribution is shown in Figures 1 and 2.

[0031] In particular, at least 70% and preferably at least 80% and more preferably at least 90% of the particles has dimensions ranging from 150 nm to 300 nm.

[0032] In a preferred embodiment, the starting material for the preparation of the composition of the invention is nanometric titanium dioxide, i.e. consisting or containing particles of titanium dioxide having nanometric dimensions (dimension of a few nanometres, less than 10 nm), which are aggregated during the preparation of the composition to form larger particles (agglomerates of nanometric particles) having the dimensions indicated above.

[0033] Contrary to what is commonly accepted in the technical-scientific field, where it is believed that the nanometric dimensions of the particles of titanium dioxide significantly increase the photocatalytic properties, also as an antimicrobial agent, the inventors of the present invention have instead found that the titanium dioxide photocatalytic activity is maintained (and to a certain extent improved) by using much larger particles.

[0034] The use of particles of the indicated dimensions, therefore of the order of hundreds of nm instead of nanometric dimensions, avoids risks of absorption of the titanium dioxide by the human organism, while maintaining the effectiveness of the composition substantially unchanged.

[0035] Furthermore, the aggregate shape according to the invention prolongs the useful life and effectiveness of the compositions of the invention.

[0036] Preferably, the particles used in the aqueous colloidal dispersion are aggregates of nanometric particles, i.e. having dimensions of less than 10 nm. The aggregate form of the particles in aqueous dispersion is evident from the analysis of the composition of the invention.

[0037] The fundamental principle of photocatalysis is the decomposition of organic compounds using light (natural or artificial) and a material so called catalyst.

[0038] The titanium dioxide is an odourless and colourless crystalline powder, with TiO 2 chemical formula, having a photocatalytic capacity.

[0039] Under the action of air and light, the electrons of the outer orbit of the titanium dioxide present in the composition of the invention are released, allowing oxygen to react with contaminants, oxidizing and transforming the same into harmless molecules such as water, carbon dioxide and inorganic salts, also making the treated surfaces semi-repellent to fluids.

[0040] When they are struck by UV rays, the particles of titanium dioxide accelerate the decomposition of a multiplicity of substances and micro-organisms, such as organic substances, microbes, nitrogen oxides, polycondensed aromatic compounds, sulphur dioxide, carbon monoxide, formaldehyde, methanol, ethanol, benzene, ethyl benzene, monoxide and nitrogen dioxide.

[0041] The composition of the invention is in liquid form, for an easy application thereof.

[0042] For the application, the composition of the invention can be nebulized with a normal nebulizer and then sprayed on walls, furniture or any other surface exposed to light to activate its antibacterial, anti-pollution and self-cleaning action without the need to resort to materials previously treated for this purpose.

[0043] In general, the recommended application is approximately 1 litre of composition per 50 m 2< of treated surface. Approximately 100 ml of composition was shown to be effective for treating a surface of approximately 5-8 square meters. The amount of composition to be applied depends on the dimensions of the environment intended to be purified: as far as its effectiveness is concerned, it can be estimated that 10 m 2< of treated surface (approximately 10-20 ml / m 2< ) can purify 500-700 m 3< of air every hour.

[0044] The effectiveness of the treatment with the composition of the invention is long-lasting and can be estimated at around 3-5 years.

[0045] Further characteristics and advantages of the present invention will appear clear from the description of the following nonlimiting examples of embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Further characteristics and advantages of the present invention will appear clear from the description of the following nonlimiting examples of embodiments, with reference to the figures of the annexed drawings, wherein: Figure 1 is a diagram showing the dimension or granulometry distribution of the titanium dioxide used according to the invention (in particular, the graph shows the cumulative distribution and the distribution density of the particle dimensions); Figure 2 is a table which shows some cumulative distribution values extracted from the graph of Figure 1. PREFERRED EMBODIMENT OF THE INVENTION

[0047] The composition of the invention comprises particles of titanium dioxide dispersed in water.

[0048] In particular, the composition is a colloidal aqueous dispersion of titanium dioxide, with particles of titanium dioxide of pre-established dimensions dispersed in water.

[0049] Water is preferably distilled water, in particular bi-distilled or tri-distilled water.

[0050] The particles of titanium dioxide are preferably in the crystalline form of anatase.

[0051] Preferably, a part of the titanium dioxide is doped, in particular with nitrogen, in order to allow the photocatalytic action even with low intensity of UV radiation.

[0052] The composition contains titanium dioxide in an amount ranging between approximately 1% and approximately 5% by weight, preferably between approximately 1.5% and approximately 2.5% by weight and in particular approximately 2%.

[0053] The percentage of doped titanium dioxide (for example with nitrogen) in the composition is for example ranging between approximately 0.1% and approximately 0.5% by weight, preferably between approximately 0.1% and approximately 0.2%.

[0054] Optionally, the composition of the invention also comprises hydrogen peroxide, for example in an amount ranging between approximately 0.1% and approximately 0.5% by weight, preferably between approximately 0.1% and approximately 0.2%.

[0055] The particles of titanium dioxide have for example the dimensions shown in the graph of Figure 1 and in the table of Figure 2.

[0056] In general, titanium dioxide is present in aqueous dispersion with particles having dimensions ranging from 100 to 300 nm, preferably from 150 to 300 nm.

[0057] In particular, at least 70% and preferably at least 80% and more preferably at least 90% of the particles have dimensions ranging from 150 nm to 300 nm and preferably about 270 nm + / - 5 nm.

[0058] As previously indicated, the particles of titanium dioxide preferably have a mean diameter, calculated as the Sauter mean diameter (SMD) or as volume mean diameter (VMD), ranging from 200 to 250 nm, more preferably from 210 to 220 nm.

[0059] Also the particles of doped titanium dioxide (with nitrogen) have for example the same dimensions as the other particles of titanium dioxide as previously defined, for example about 270 nm + / - 5 nm.

[0060] In order to make the product visible, the composition optionally comprises, furthermore, an additive of the class of optical brighteners (also known as optical bluing agents, optical whiteners, fluorescent bleaching agents), i.e. a chemical compound which, added to a product, is able to improve the chromatic characteristics thereof.

[0061] The additive, struck by ultraviolet radiation, is able to re-emit, by fluorescence, visible light of colour between purple-blue and blue-green depending on the dye used.

[0062] For example, the composition of the invention comprises an optical brightener known as "Fluorescent brightener 220", CAS No. 16470-24-9, of general formula C 40 H 44 N 12 O 16 S 4 ·4Na, IUPAC name: tetrasodium 4,4'-bis[[4-[bis(2-hydroxyethyl)amino]-6-(4-sulphonatoanilino)-1,3,5-triazin-2-yl]amino]stilbene-2,2'-disulphonate].

[0063] The composition of the invention is in liquid form, with a pH ranging from 6 to 8, a specific weight of approximately 1 g / ml and boiling point of approximately 100°C.

[0064] The composition of the invention is preferably prepared as follows.

[0065] The particles of titanium dioxide are dispersed in distilled water, in particular by means of a cowles toothed disc disperser.

[0066] In preferred embodiments, nanometric particles of titanium dioxide are used as starting material, having dimensions smaller than approximately 10 nm, preferably approximately 4-6 nm, in particular approximately 5 nm. In the dispersion / mixing step, the nanometric particles aggregate into larger aggregate particles, having the dimensions defined above.

[0067] To obtain this result, the preparation process comprises a mixing step in which TiO2 nanometric particles, having dimensions smaller than 10 nm, are mixed in distilled water, in particular by means of a disperser provided with at least one impeller, in particular a cowles toothed disc disperser, i.e. having at least one impeller provided with a toothed disc.

[0068] Preferably, the mixing step comprises a first dispersion step carried out with a first rotation speed of the impeller disperser; and a second dispersion step carried out with a second rotation speed of the impeller disperser, greater than the first rotation speed; the two dispersion steps can have different durations, approximately every few minutes, also depending on the respective quantities of titanium dioxide and water.

[0069] For example, the mixing speed is generally around 250-300 rpm. Advantageously, after a first dispersion step at a pre-established speed, for example 250 rpm, the speed is increased in a second dispersion step, for example at 300 rpm.

[0070] The dispersion temperature is approximately 50-60°C, in particular a first dispersion step is carried out at approximately 50-54°C, then a second dispersion step at approximately 60-65°C.

[0071] Advantageously, an emulsifying system is used having Hydrophilic-Lipophilic Balance (HLB) of approximately 7.

[0072] For example, the emulsifying system contains an emulsifier of an anionic / non-ionic nature.

[0073] The emulsifying system is for example used in an amount approximately equal to 15% with respect to titanium dioxide.

[0074] The process is preferably carried out under vacuum, with a vacuum time of approximately 30 min at a negative pressure of approximately 0.3 bar.

[0075] In this way an aqueous dispersion of TiO2 is obtained in anatase crystalline form with agglomerates of desired granulometry.

[0076] In this way, any risk to the human organism connected to the possible absorption of nanometric particles of titanium dioxide is avoided, without compromising the effectiveness of the composition.

[0077] Numerous experimental tests confirm the efficacy of the compositions according to the invention, which prove in particular to possess a powerful sanitizing and bactericidal action.

[0078] In particular, tests were carried out according to ISO 27447:2009 which defines the criteria for the experimental evaluation of the antimicrobial activity of photocatalytic materials.

[0079] The tests confirm the efficacy both towards E.Choli ATCC 8739 and towards Staphylococcus aureus ATCC6538P (considered as general models for Gram negative and Gram positive bacteria, respectively) .

[0080] Further confirmation came from tests according to ISO 10678:2010, UNI 11484:2013, ISO 22197:2007.

[0081] Some tests were also carried out with substantial modifications of the experimental conditions in order to demonstrate the photocatalytic activity even in adverse conditions (absence of illumination and UV radiation). The compositions of the invention prove to be effective even in these conditions (without the use of UV radiation).

[0082] Further experiments have been carried out in the field, i.e. by applying the compositions of the invention on surfaces in different hospital environments.

[0083] Ultimately, the test results confirm the photocatalytic activity of the compositions of the invention and attest to a significant antimicrobial activity. As reported in the literature, these data can be generalized to the most common pathogens present in the environment.

[0084] Finally, it is understood that further modifications and variations may be made to the composition described and illustrated herein which do not depart from the scope of the appended claims.

Claims

1. A sanitization composition for sanitization-purification of surfaces and environments, comprising particles of titanium dioxide dispersed in water to form an aqueous colloidal dispersion and having dimensions ranging from 100 to 300 nm, preferably from 150 to 300 nm; characterized by containing titanium dioxide in an amount ranging between 1% and 5% by weight.

2. The composition according to claim 1, wherein the particles of titanium dioxide have a mean diameter, calculated as Sauter mean diameter (SMD) or as volume mean diameter (VMD), ranging from 200 to 250 nm, preferably from 210 to 220 nm.

3. The composition according to claim 1 or 2, containing titanium dioxide in an amount ranging between approximately 1.5% and approximately 2.5% by weight and in particular about 2% by weight.

4. The composition according to one of the preceding claims, wherein the particles of titanium dioxide are in the anatase crystal form.

5. The composition according to one of the preceding claims, wherein the particles of titanium dioxide in aqueous colloidal dispersion are aggregates of nanometric particles having dimensions smaller than 10 nm.

6. The composition according to one of the preceding claims, also comprising doped titanium dioxide, in particular titanium dioxide doped with nitrogen, in an amount ranging between approximately 0.1% and approximately 0.5% by weight, preferably between approximately 0.1% and approximately 0.2% by weigh.

7. The composition according to one of the preceding claims, comprising hydrogen peroxide, for example in an amount ranging between approximately 0.1% and approximately 0.5% by weight, preferably between approximately 0.1% and approximately 0.2% by weight8. The composition according to one of the preceding claims, comprising at least one optical brightener that absorbs ultraviolet radiation and re-emits visible light by fluorescence, for example "Fluorescent brightener 220", CAS No. 16470-24-9.

9. A sanitization method for the sanitization-purification of surfaces and environments, comprising a step of applying on a surface a composition comprising an aqueous colloidal dispersion of particles of titanium dioxide having dimensions ranging from 100 to 300 nm, preferably from 150 to 300 nm, characterized in that said composition contains titanium dioxide in an amount ranging between 1% and 5% by weight.

10. The method according to claim 9, comprising a step of activating the particles of titanium dioxide by electromagnetic radiation or induction, for example by UV radiation, light radiation, induction.

11. The method according to claim 9 or 10, wherein the particles of titanium dioxide have a mean diameter, calculated as Sauter mean diameter (SMD) or as volume mean diameter (VMD), ranging from 200 to 250 nm, preferably from 210 to 220 nm.

12. The method according to one of the claims from 9 to 11, wherein the composition contains titanium dioxide in an amount ranging between approximately 1.5% and approximately 2.5% by weight and in particular around 2% by weight.

13. The method according to one of the claims from 9 to 12, wherein the particles of titanium dioxide are in the anatase crystal form.

14. The method according to one of the claims from 9 to 13, wherein the particles of titanium dioxide in aqueous colloidal dispersion are aggregates of nanometric particles having dimensions smaller than 10 nm.

15. The method according to one of the claims from 9 to 14, wherein the composition also contains doped titanium dioxide, in particular titanium dioxide doped with nitrogen, in an amount ranging between approximately 0.1% and approximately 0.5% by weight, preferably between approximately 0.1% and approximately 0.2% by weight.

16. The method according to one of the claims from 9 to 15, wherein the composition contains hydrogen peroxide, for example in an amount ranging between approximately 0.1% and approximately 0.5% by weight, preferably between approximately 0.1% and approximately 0.2% by weight17. The method according to one of the claims from 9 to 16, wherein the composition contains at least one optical brightener that absorbs ultraviolet radiation and re-emits visible light by fluorescence, for example "Fluorescent brightener 220", CAS No. 16470-24-9.

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