IT202100016025A1 - Antibacterial and antiviral coating for surfaces - Google Patents

Description

Title: "Antibacterial and antiviral coating for surfaces?

DESCRIPTION

There are numerous studies and research aimed at creating coatings characterized by properties? antibacterial.

The possibility? to contain the bacterial load has a positive effect especially from a health point of view if we think of the possible applications on manufactured items such as handles or on surfaces such as tables, chairs and furnishings in general.

The prior art describes many processes for treating surfaces by applying antibacterial preparations.

As demonstrated by research published by (

Emerging nanomaterials for antibacterial textile fabrication. Naunyn-Schmiedeberg's Arch Pharmacol (2021). https://doi.org/10.1007/s00210-021-02064-8), the activity? antimicrobial made from nanoparticles ? used to inhibit bacterial growth on the surface of materials, in order to avoid the spread of pathogenic bacteria and to protect the substrate from damage induced by the bacteria themselves.

In agreement with the scientific literature (

Nanostructured Surface Finishing and Coatings: Functional Properties and Applications. Materials 2021, 14, 2733. https://doi.org/10.3390/ ma14112733), a number of antibacterial/antifouling products have been developed using inorganic compounds such as silver oxide (Ag2O), zinc oxide (ZnO), copper oxide (CuO) and titanium dioxide (TiO2) whose functioning and effectiveness depend on the substances used and their mechanisms of action: release of ions, physical interactions with the bacterial cell and generation of reactive oxygen species .

An important limitation of the technologies and processes known in the art ? represented by the short duration of the antibacterial effect, caused by the degradation or removal of the applied layer.

Summary of the invention

The authors of the present invention have surprisingly found how to make a coating for surfaces of various kinds characterized by properties antibacterial and antiviral, which is particularly resistant to washing cycles

Object of the invention

In a first object, the invention describes a process for the preparation of a surface having properties antibacterial and/or antiviral.

The preparation of a matrix to be applied to this surface in order to confer properties? antibacterial and/or antiviral represents a second object of the invention.

The surfaces obtained having properties? antibacterial and/or antiviral agents represent further objects of the invention.

In a second object ? described a method for conferring properties? antibacterial and/or antiviral to surfaces.

Detailed description of the invention

In a first object, the invention describes a process for the preparation of surfaces having properties antibacterial and/or antiviral.

In particular, this process comprises the preparation of a matrix comprising an active ingredient.

For the purposes of the present invention, the matrix ? type polymer and pu? include: an acrylic resin, polyurethane resin, epoxy resin, polyester resin, vinyl resins, resins from glyoxal derivatives (possibly without formaldehyde), melamine resins.

In a preferred aspect of the invention, the matrix ? based on acrylic resin and, more? preferably, acrylic styrene.

The active principle used for the preparation of the matrix? selected from the group comprising: silver salts, zinc oxide and coordination compounds, zinc pyrithione, copper oxides, quaternary ammonium compounds, chitosan, polyhexamethylenebiguanide chloride, quaternary silanes, triclosan (5-chloro-2-(2, 4-dichlorophenoxy)phenol), derivatives of isothiazolinone.

According to the present invention, it can be used a single active ingredient or a mixture of active ingredients, to exploit any synergy between them.

According to a preferred aspect of the present invention, the active principle ? represented by silver chloride.

The matrix described by the present patent application can also include one or more components to improve the formulation.

For example, rheological additives, antifoaming agents, wetting agents, preservatives and sequestrants may be added.

The rheological additives can be represented, for example, by emulsions of acrylic polymers or by inorganic agents such as, for example, kaolin, titanium oxide, calcium and magnesium carbonate, silicon oxide and derivatives.

The defoamers can be silicone or non-silicone compounds.

The wetting agents can be represented by alcohols, anionic, cationic, amphoteric, non-ionic surfactants, having high or low molecular weight.

Preservatives can be represented, for example, by anti-fermenting substances.

The sequestering agents can be represented, for example, by derivatives of phosphorus.

For the purposes of the present invention, the matrix ? present in a quantity of about 1-50% (weight/weight), and more? preferably 4-20% (w/w).

For the purposes of the present invention, the active ingredient is added to the matrix in a quantity? of about 0.0030-10% (p/p), and more? preferably about 1% (w/w).

In one embodiment of the invention, the matrix comprises an acrylic resin and a silver salt.

In a preferred embodiment of the invention, the matrix comprises an acrylic styrene resin and silver chloride.

For the preparation of the matrix object of the invention, the active ingredient, according to the quantities? indicated above, added to the matrix under stirring.

The aim of the agitation is to obtain a homogeneous dispersion of the active principle inside the matrix.

Pi? in particular, the? agitation ? conducted at speed? about 50-2000 rpm and preferably about 1000 rpm.

Pi? in particular, the? agitation ? maintained for a period of time of 2-30 minutes and, preferably, of 30 minutes.

Pi? in particular, during? stirring, the temperature? of about 4-45°C, preferably 20°C.

As for the other components, such as rheological additives, wetting agents, preservatives and sequestrants, these are added individually in concentrations ranging from about 0-8% (w/w) under stirring and can be added to the matrix after addition of the active ingredient or, preferably, before.

The matrix comprising the active ingredient or ingredients according to what is described above represents a further object of the present invention.

The present invention describes the preparation of surfaces so? to confer property? antibacterial and/or antiviral; these surfaces are obtained by coating with the matrix of the invention.

With the term ?antibacterial? do you mean the capacity? to inhibit and/or decrease and/or contain bacterial contamination, with respect to an initial contamination.

With the term ?antiviral? do you mean the capacity? to inhibit and/or decrease and/or contain viral contamination, compared to an initial contamination.

In a preferred aspect of the present invention, such surfaces have properties antibacterial and/or antiviral.

For the purposes of this patent application, a surface ? to be understood as including surfaces of the porous type and surfaces of the non-porous type.

With ?porous type surfaces? (or porous) means preferably concrete (untreated), wood (untreated), stone materials (granite, marble, stone, etc. untreated), fabrics and nonwovens (natural, artificial or synthetic, untreated), paper or cardboard (untreated).

With ?non-porous type surfaces? (or non-porous) preferably means concrete (treated), wood (treated), metal, glass, plastic, ceramic materials.

With ?treaty? we mean a material whose surface, in itself? porous, ? has it been subjected to a treatment that has resulted in the loss of porosity, such as painting for example; therefore, this material, which by its nature is porous, ? was treated to make its surface non-porous before applying the matrix of the invention.

Metallic surfaces include metal surfaces, such as: iron, copper, aluminum or metal alloy surfaces, such as steel and brass.

Plastic surfaces include surfaces in a polymeric material selected from the group which includes: polyvinyl chloride (PVC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), etc.

Particular examples of surfaces include artefacts and surfaces such as, for example: floors, walls, ceilings, or portions thereof; taps, shelves, furnishings, furniture, building structures, plastic supports, protective coatings for manufactured articles (cases), seats, home accessories, interiors of means of transport (cars, trains, planes), internal coatings of vehicles transport (ambulances, etc.).

For the preparation of surfaces having activity? antibacterial and antiviral according to the invention, one proceeds with a phase a) of dispersion of the active ingredient in the matrix; b) application of the matrix cos? prepared on a surface as described above.

In a preferred aspect of the invention, the surface to be treated must be thoroughly cleaned before applying the matrix.

In any case, even in the absence of cleaning, the matrix object of the invention has shown excellent properties? of adhesion and capacity? antibacterial and/or antiviral.

In particular, this application pu? be conducted, for example, by:

- brush,

- roller,

- spray,

- dip coating.

According to a first aspect of the invention, the preparation of the matrix can be applied as such, while, in alternative aspects, pu? be suitably diluted.

The dilution can? for example responding to needs related to the application technique or the type of surface to be treated.

After the application phase a), a phase b) of drying of the matrix follows.

For this purpose, drying can be conducted at a temperature of about 8-50?C and preferably 18-30?C or can? be carried out in the oven to accelerate the aforementioned drying procedures, using temperatures that vary according to the exposure time.

Drying? conducted for an appropriate period of time, ranging from a few minutes to a few days.

The temperature and drying time conditions depend on the thickness of the finish applied, the nature of the surface and the humidity conditions.

For example, 60 minutes at 20?C with a?humidity? of 65% R.H. can give a dry touch result, while 12 hours in the same conditions may be necessary for deep drying. Using an oven, by way of example, but not limited to these conditions, drying at 100-120°C for 5 minutes has been successfully carried out.

For the purposes of the present invention, the application can be carried out in a single layer or by applying successive layers, after the previous layer ? dried completely.

The surfaces obtained according to what is described above represent further objects of the present invention.

In particular, these are surfaces obtained after the application and drying phases, possibly preceded by cleaning.

The present invention has as another object a method of imparting properties? antibacterial and/or antiviral to a surface according to the process described above.

The property? antibacterial on plastic surfaces and non-porous surfaces ? was determined according to JIS Z 2801:2010 and ISO 22196:2011.

According to a particular aspect of the invention, the method proves to be effective, with activity antibacterial against both Gram positive and Gram negative microorganisms.

For the purposes of the present invention, Gram positive microorganisms are selected from the group which includes: Bacillus, Clostridium, Enterococcus, Lactobacillus, Listeria, Micrococcus, Staphylococcus, Streptococcus, etc.

Pi? in particular, these Gram positive microorganisms include, for example: Bacillus subtilis, Clostrium difficile, Enterococcus faecium, Enterococcus faecalis, Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Staphylococcus lugdunensis etc.

For the purposes of the present invention, Gram negative microorganisms are selected from the group which includes: Campylobacter, Enterobacter, Acinetobacter, Escherichia, Klebsiella, Morganella, Proteus, Shigella, Salmonella, Neisseria, Pseudomonas, Vibrio, etc.

As for the properties? antivirals, these are evaluated according to ISO 21702:2019.

According to a particular aspect of the invention, the method proves to be effective against viruses.

For the purposes of the present invention, such viruses are selected from the group which includes: coronaviruses, herpes viruses, rotaviruses, adenoviruses, noroviruses, enteroviruses, rhinoviruses, etc.

In a preferred aspect of the present invention, such viruses are coronaviruses.

In an even more particular of the invention, these viruses are represented by the SARS-Cov2 coronavirus responsible for the acute respiratory disease Covid19.

The procedure used for the evaluation of the activity? antiviral, object of the present invention, took into consideration the NL63 strain, against which it proved to be effective.

In one particular aspect, these properties antibacterial and/or antiviral properties remain even after surface washing cycles and for a long time enduring wear and tear.

For example, ? been demonstrated that a surface treated according to the present invention can? keep its properties antibacterial and/or antiviral up to 10, 50, 150, 200, 250 and even up to about 300 washing cycles.

For the purposes of the present invention, a wash cycle is intended to be carried out at room temperature with a solution comprising a non-ionic surfactant or water/alcohol hydroalcoholic mixtures, with which a microfiber cloth is impregnated, with which the surface to be tested is cleaned (dimensions 25 cm x 25 cm) , with rotational movements for about 5 seconds.

In particular, the detergent solution has a concentration of about 2 g/l or ? represented by a water/alcohol (ethanol) solution in ratios of about 30/70.

Example 1

Preparation of surfaces having properties? antibacterial and/or antiviral. Sample A ? was carried out in the following way: Phase 1 - solution preparation.

Under constant stirring, 200 grams of acrylic styrene resin were added in water to form an aqueous solution at the concentration of 200 g/l. 20 grams of sodium hexametaphosphate, 0.1 grams of antifermentative (preservative which prevents the formulations from rotting over time following long storage periods), 10 grams of anionic surfactant and 5 grams of silver chloride have been added to this solution. The solution ? been kept under stirring for about 15 minutes before application.

Stage 2 - application.

The solution prepared in Phase 1 ? been applied to a PVC polymer material by spreading application (roller application).

Phase 3 - Drying/polymerization.

The polymeric material treated? been dried for 24 hours at the temperature of 20?C hours before its use.

Example 2

The surface obtained in Example 1 ? been subjected to experiments to verify the properties? antibacterial and antiviral.

The tests described were carried out on the same substrates and also subjected to various washing/cleaning cycles (10 and 300 cycles) according to the procedure previously described in order to evaluate the maintenance of the property? conferred or the eventual release of the active principle.

The results obtained with the EN ISO 22196:2011 standard for surfaces not subjected to washing and subjected to 10 washing cycles are shown below:

Activities antibacterial against E. coli

Activities antibacterial against S. aureus

Activities antibacterial against E. coli - after 10 washes

Activities antibacterial against S. aureus ? after 10 washes

The results obtained with the EN ISO 22196:2011 standard after subjecting the surfaces obtained according to the invention to 300 washing cycles are shown in the table below.

The results show a strong activity antibacterial (A > 5.7 for Escherichia coli and A > 5.4 for Staphylococcus aureus).

The results obtained with the ISO 21702:2019 standard -Measurement of antiviral activity on plastics and other non-porous surfaces show a strong activity antiviral on the unwashed sample with activity? antiviral A? 1, demonstrating a strong activity? virucidal.

The results of the experimental tests have demonstrated that the matrix of the invention exerts an activity antibacterial and antiviral.

From reading the above description of the present invention, the numerous advantages offered will be evident to the person skilled in the art.

In particular, the described surface finishing obtained by applying the matrix of the invention ? able to confer properties? antibacterial and/or antiviral to a wide range of surfaces, from metal or wood to polymeric materials.

Thanks to the excellent skills stickers, the matrix ? able to offer such properties? for a long time, resisting use and wear and, above all, washing carried out, in an exceptional way.

The process for the preparation of the matrix and for its application to the surfaces of interest are, however, simple and practical to implement.

To the invention as described above, an expert person, in order to satisfy contingent and specific needs, will be able to make adaptations, modifications and replacements of elements with other functionally equivalent ones, without however departing from the scope of the claims set out below.

Claims (13)

1. A process for preparing a surface having antibacterial and/or antiviral agents comprising the steps of: - preparing a polymer matrix selected from the group comprising: an acrylic resin, polyurethane resin, epoxy resin, polyester resin, vinyl resin, resin from glyoxal derivatives, melamine resin, comprising one or more? active ingredients selected from the group which includes: silver salts, zinc oxide and coordination compounds, zinc pyrithione, copper oxides, quaternary ammonium compounds, chitosan, polyhexamethylenebiguanide chloride, quaternary silanes, triclosan (5-chloro-2-( 2,4-dichlorophenoxy)phenol), isothiazolinone derivatives; - applying this matrix to said surface; - let the matrix dry on the surface cos? obtained. 2. The process according to claim 1, wherein said active ingredient is included in a quantity? about 0.0030-10% and preferably about 1% (w/w). 3. The process according to claim 1 or 2, wherein said matrix comprises an acrylic resin and a silver salt. 4. The process according to any one of the preceding claims, wherein said matrix comprises an acrylic styrene resin and silver chloride. 5. The process according to any one of the preceding claims, further comprising rheological additives, antifoaming agents, wetting agents, preservatives and sequestrants. 6. The process according to any one of the preceding claims, wherein said matrix is applied to said surface by: - brush, - roller, - spray, - dip coating. 7. The process according to any one of the preceding claims, wherein said surface is? porous or ? non-porous. 8. The process according to the preceding claim, wherein said porous surface comprises surfaces in cement (untreated), wood (untreated), stone materials (granite, marble, stone, etc. untreated), fabrics and non-wovens ( natural, artificial or synthetic, untreated), paper or cardboard (untreated). 9. The process according to the preceding claim, wherein said non-porous surface comprises surfaces made of concrete (treated), wood (treated), metal, glass, plastic, ceramic materials. 10. A surface obtained with the process according to any one of the preceding claims. 11. A method of conferring ownership? antibacterial and/or antiviral to the surfaces comprising treating said surfaces according to the process of any one of the preceding claims from 1 to 9. 12. The method according to the preceding claim in which such properties? antibacterial and/or antiviral properties remain following washing cycles of said surfaces. 13. The method according to the preceding claim in which such properties? antibacterial and / or antiviral remain after 10, 50, 100, 150, 200, 250 and even more? preferably following 300 washing cycles of said surfaces.