EP4150013A1

EP4150013A1 - Biocidal, antiseptic, non-solvent-based environmentally-friendly coating containing metal particles having a flat lamellar structure

Info

Publication number: EP4150013A1
Application number: EP21725501.7A
Authority: EP
Inventors: Michel Desbois
Original assignee: Magguilli Stephane
Current assignee: Magguilli Stephane
Priority date: 2020-05-11
Filing date: 2021-05-11
Publication date: 2023-03-22
Also published as: KR20230010211A; FR3109943A1; US20230227667A1; FR3109943B1; CA3177956A1; AU2021272305A1; WO2021228902A1; JP2023526042A

Abstract

The present invention relates to a biocidal coating composition for a surface, comprising overlapping flat lamellar metallic nanoparticles and/or microparticles having a diameter of less than 45 microns, in suspension in a binder comprising an epoxy resin, a thixotropic agent and a natural diluent selected from among water, preferably demineralized water, and/or ethylene glycol and/or denatured alcohol. Moreover, the invention also relates to a coating process comprising a step of applying said composition, and to the use of the coating composition according to the invention for coating a surface.

Description

Title of the invention:

BIOCIDAL, ANTISEPTIC, ECOLOGICAL NON-SOLVENT COATING, WITH PARTICLE

METAL A

FLAT LAMELLAR STRUCTURE

The present invention relates to a biocidal coating composition of a surface comprising flat lamellar metal nanoparticles and / or microparticles of diameter less than 45 microns which overlap, suspended in a binder comprising an epoxy resin, a thixotropic agent and a natural diluent chosen from water, preferably demineralized, and / or ethylene glycol and / or denatured alcohol. In addition, the invention also relates to a coating process comprising a step of applying said composition, and G using the coating composition according to the invention to coat a surface.

STATE OF THE ART

[0002] Copper has antibacterial properties which have been recognized for centuries. Humans have harnessed the naturally antibacterial properties of copper since the earliest ages. It has been clearly shown by numerous scientific studies carried out for decades that copper is able to eradicate the most resistant bacteria, molds and viruses. It is also known that these virtues are used for the prevention of nosocomial infections.

[0003] Scientific literature cites the effectiveness of copper in killing and inactivating several types of pathogenic bacteria, molds and viruses including: Acinetobacter baumannii; Adenovirus; Aspergillus niger; Candida albicans; Campylobacter jejuni; Clostridium difficile; Enterobacter ae ogenes; Escherichia coli 0157.Ή7; Helicobacter pylori; Influenza A (H1N1); Legionella pneumophilia; Listeria monocytogenes; Poliovirus; Pseudomonas aeruginosa; Salmonella enteriditis; Tubercle bacillus; Staphylococcus aureus; Vancomycin resistant enterococcus aureus resistant to methicillin.

[0004] Submerged surfaces such as ship hulls must be protected against the development on them of algae or marine animals, failing which the durability and functionality of the structures comprising these surfaces would be significantly affected. In particular, the resistance of the hulls of ships to sliding in water would be considerably increased and the surfaces of these hulls could be damaged.

It is well known to provide this protection by means of so-called "antifouling" paints. The major drawback of effective paints is that they contain toxic particles which diffuse into the environment, and new international standards relating to environmental protection are increasingly restrictive from this point of view. Paints meeting these international standards, especially paints intended for pleasure boats, have the disadvantage of being significantly less effective than previous paints, involving more frequent fairings of boats and therefore prolonged periods of immobilization of the latter as well as increased user costs.

For such paints or antifouling coatings, it is known to use particles of copper or alloy of copper and nickel suspended in a binder. However, these paints or coating are not entirely satisfactory in terms of effective protection of submerged surfaces and respect for the environment.

[0007] Document US Pat. No. 5,284,682 discloses a coating composed of lamellar particles, necessarily isolated from each other so as to inhibit corrosion of the metal surfaces on which said coating has been applied. In addition, the composition disclosed by this document does not use a natural solvent.

[0008] Document FR2894974 discloses a product for protecting a surface intended to be submerged, such as a ship's hull, comprising particles spaced apart from each other, a binder and a diluent.

The configuration of these coatings promotes microscopic imprisonment of air molecules (oxygen), favorable to the proliferation of bacteria and / or molds and / or fungi, furthermore resulting in the destruction of the substrate, of polyester type by the presence water and acetic acid, resulting from the hydrolysis of the resin which causes the passage of water with a significant risk of irreversible destruction of the ship's hull at the level of the submerged part. In addition, the dispersion of said nanoparticles and / or microparticles in the environment cannot be avoided due to the chosen conformation, allowing viruses, microbes and air trapping to settle, having effects on the antiseptic properties of copper which does not can be kept

Document WO2016 / 081476 discloses a composition comprising non-metallic particles, an epoxy resin and a natural solvent. The absence of a dispersing agent is problematic because said particles are not kept in suspension.

[0011] In addition, most of the current compositions systematically use powders with a cylindrical-type structure, preferably spherical, with a particle size greater than or equal to 45 microns. Said particles are of irregular shape with respect to each other, exhibiting a lower production stroke which does not allow continuity of the ionic properties of copper and / or cupronickel. Their irregular shapes and their overlap one on the other promote microscopic imprisonment of air molecules (oxygen), favorable to the proliferation of bacteria and / or molds and / or fungi. In boating, for example, this promotes the destruction of the substrate, of the polyester type by the presence of water and acetic acid, resulting from the hydrolysis of the resin which causes the passage of water with a significant risk of irreversible destruction. of the ship's hull at the level of the submerged part.

These cylindrical type powders, preferably spherical, have a "round" structure, deforming the structure initially treated, forcing a surfacing of said protection, following their application, which generates a significant reduction in the thickness of the coating .

In addition, in the case of copper powder composites, the biocidal properties generated by the copper find direct application in a large number of technical fields, such as agribusiness, the pharmaceutical industry, the field of health, water sports, sports structures, school complexes, building constructions, establishments open to the public, airports, stations, roof protection among others. However, the copper and / or cupronickel powders used to date have a spherical, disorganized structure, which cannot provide a standard and regular thickness, therefore, not allowing optimal biocidal protection.

These preferably spherical metal balls, as indicated above have the risk of trapping air bubbles in the thickness of the coating, characterized in Figure 1. These bubbles promote the breakage of protection necessary between each metal ball and the surface that needs to be leveled, by relatively abrasive sanding in order to regain a smooth surface, but uneven in terms of thickness. Indeed, the surface must be regularly sanded to remove the successive layers of resins over time, the surface must therefore be re-sanded to find a so-called anti-fouling coating.

[0016] Thus, there continues to be the need for a biocidal coating composition which solves all of the problems mentioned above.

The object of the present invention is therefore to solve the aforementioned technical problems by providing a composition containing nanoparticles and / or microparticles of copper and / or cupro-nickel with flat lamellar structures which overlap, dispersed in a binder comprising in particular an agent. thixotropic allowing regular, controlled application by film of different thicknesses thus creating a “placoid scale” type coating, and also making it possible to preserve the antiseptic properties of copper by eradicating molds, bacteria and viruses, while minimizing costs production by reducing the amount of epoxy binder used to obtain said composition.

DISCLOSURE OF THE INVENTION

[0018] According to a first aspect, the invention relates to a biocidal coating composition with a surface comprising flat lamellar metallic nanoparticles and / or microparticles with a diameter of less than 45 microns which overlap, suspended in a binder comprising:

- an epoxy resin;

- a thixotropic agent;

- a natural diluent chosen from water, preferably demineralized, and / or ethylene glycol and / or denatured alcohol.

[0019] For the purposes of G invention, the term “composition” is understood to mean a combination of two or more materials of different types. In the present invention, it is the combination of a binder with metallic nanoparticles and / or microparticles, preferably copper and / or cupronickel and / or metallic. The composition according to the invention makes it possible not to trap air molecules (oxygen) in the and / or protected supports.

By flat, overlapping lamellar particles is understood according to the present invention thin plates, each being of the order of a few nanometers or a few microns, said plate being by their shape, thin, flat, juxtaposed and nested , with respect to each other, forming a smooth mesh without surface defect making it possible to avoid the dispersion of said nanoparticles and / or microparticles in the environment while retaining the antiseptic properties of copper. These particles are elongated in shape, resembling a flat ovoid shape, as shown schematically in Figure 3, and shown by microscopic photograph in Figure 4, allowing juxtaposition and nesting between them.

[0021] This is similar to what is found naturally on the skin of certain reptiles and fish. For these reasons, the coating is referred to in the text as a "placoid scale" type. Said "placoid scales" are similar to the subcutaneous denticles of cartilaginous fish such as the scales of Selachians, namely sharks and rays, forming small flattened teeth, overlapping in order to play a hydrodynamic role by making the skin of said fish raincoat. In addition, said flat lamellar nanoparticles and / or microparticles overlap to allow the coating on which the composition is applied to be made impermeable to external agents such as viruses, bacteria or the various molds that may form.

[0022] The lamellar nanoparticles of the "placoid scale" type ensure homogeneity and a guarantee of continuity of protection between each nanoparticles and / or microparticles, without any air bubbles being trapped.

By nanoparticles and / or microparticles, is understood within the meaning of the invention, particles of small sizes, of the order of a few nanometers or a few microns, preferably the size of said nanoparticles is between 5 nm to 9 nm and the size of the microparticles is between 1 µm to 20 µm. The diameter of said particles used according to the invention is less than 45 microns in size.

The present invention makes it possible to retain the powerful naturally biocidal and antibacterial properties of copper and / or cupronickel in its raw state once the support has been covered.

[0025] For the purposes of the present invention, the term “binder” is understood to mean a substance which binds the flat lamellar nanoparticles and / or microparticles according to the invention to one another. The binder ensures the cohesion of the nanoparticles and / or microparticles for the formation of a "placoid scale" type protection.

The overlap of said nanoparticles and / or microparticles of copper and or cupronickel with flat lamellar structures makes it possible to guarantee perfect cohesion of the particles while minimizing the amount of binder used.

By epoxy resin is understood thermosetting resins having good mechanical and chemical properties. These resins include a base and a hardener. They are manufactured by polymerization of epoxy monomers with a hardener (crosslinking agent) which can be based on acid anhydride, phenol or most often amine (polyamine, aminoamide): they are three-dimensional polymers. . The epoxy resin being an expensive element, the reduction in its use makes it possible to reduce the costs incurred and that of the coating composition according to the invention. The present invention allows, because of its overlapping configuration of the particles to use a less important quantity of epoxy resin, and therefore to achieve significant savings of the main materials of said invention while increasing the initial protection of the nanoparticles and / or microparticles used in the invention. said composition. By epoxy resin is also meant the polymerization agent thereof. An example of a polymerization agent may be that available commercially under the reference RESOLCOAT 1014. This epoxy resin and the polymerization agent can also be those commercially available under the references CLEAR COAT / A and CLEAR CO AT / B, respectively, with dilution with trichlorethylene ethylene ketone or methyl ethylene ketone.

Preferably, the composition comprises between 1 and 50%, preferably between 5 and 45%, even more preferably between 5 and 35%, by total weight of the composition of said epoxy resin.

Examples of such epoxy resins are commercially available under the reference RESOLCOAT 1014, or other brands.

By thixotropic agent is understood according to the invention a dispersing agent, making it possible to maintain the nanoparticles and / or microparticles used in the formulation in the binder in suspension, and to provide them with thixotropic properties, namely to be able to change from a liquid state to a solid state under the effect of constant stress. This will allow the composition according to the invention once affixed to the surface to be coated to achieve its biocidal power. Left to stand for a long time, the thixotropic fluid will restructure itself and allow it to transform into a more or less viscous product, thus making it possible to keep the metal particles in suspension, Its viscosity increases and can tend to infinity, depending on the type of mixture research

Preferably, said composition comprises between 10 and 45%, preferably between 15 and 45%, even more preferably between 28 and 45%, by weight of said thixotropic agent.

[0032] Preferably, said thixotropic agent is colloidal clay consisting of a mixture of sodium, magnesium and lithium silicates.

[0033] Even more preferably, said thixotropic agent consists of a mixture of sodium silicates, magnesium and lithium is the product Laponite ^® RD.

[0034] For the purposes of the present invention, the term “natural diluent” is understood to mean a substance allowing the dilution of the various elements making up the coating composition according to the invention.

Said diluent will completely evaporate after application of the coating composition to the surface to be coated.

Thus, the percentages of constituent of the composition discussed here are those before application.

Preferably, said natural diluent is chosen from water, preferably demineralized, and / or ethylene glycol and / or denatured alcohol,

Preferably, the composition comprises between 10 and 45%, preferably between 15 and 45%, even more preferably between 28 and 45%, by total weight of the composition of natural diluent.

Preferably, said copper and / or cupronickel nanoparticles have a diameter of between 5 nm to 9 nm.

Preferably, said copper and / or cupronickel microparticles have a diameter of between 1 μm to 20 μm.

According to a preferred embodiment of the invention, said composition comprises between 10 and 95%, preferably between 40 and 95%, even more preferably between 55 and 95%, by total weight of the composition of said nanoparticles and / or microparticles. By biocide, is understood within the meaning of the invention, the definition of the term "biocide" of the European Parliament and of the council n ° 98/8 / EC of February 16, 1998 concerning the placing on the market of biocidal products (JO / CE n ° L 123 of April 24, 1998) which define them as "Active substances and preparations containing one or more active substances which are presented in the form in which they are delivered to the user, which are intended to destroy , repel or render harmless organisms, to prevent their action or to combat in any other way, by chemical or biological action. "

Preferably, said metallic nanoparticles and / or microparticles are nanoparticles and / or microparticles of copper and / or cupronickel.

[0044] According to a particular embodiment of the invention, the composition comprises:

- From 10 to 95% of nanoparticles and / or microparticles;

- From 1 to 50% of epoxy resin;

- From 1 to 30% of a thixotropic agent, preferably Laponite® RD;

- From 10 to 45% of natural diluent chosen from water, preferably demineralized, and / or ethylene glycol and / or denatured alcohol,

[0045] According to an alternative embodiment of the invention, the composition comprises:

- From 40 to 95% of nanoparticles and / or microparticles;

- From 5 to 45% of epoxy resin;

- From 5 to 30% of a thixotropic agent, preferably Laponite® RD;

- From 15 to 45% of natural diluent chosen from water, preferably demineralized, and / or ethylene glycol and / or denatured alcohol.

According to an alternative embodiment of the invention, the composition comprises:

- From 55 to 90% of nanoparticles and / or microparticles;

- From 5 to 35% of epoxy resin;

- From 5 to 30% of a thixotropic agent, preferably Laponite ® RD;

- From 28 to 45% of natural diluent chosen from water, preferably demineralized, and / or ethylene glycol and / or denatured alcohol.

[0047] According to an alternative embodiment of the invention, the composition comprises:

- From 45 to 99% of nanoparticles and / or microparticles;

- From 5 to 45% of epoxy resin;

- From 7 to 45% of a thixotropic agent, preferably Laponite ® RD;

The invention provides a composition applicable to a surface intended to be immersed or to remain in the open air. The application of this composition makes it possible to provide improved protection efficiency of said surface, whether or not it is submerged.

After application to the surface, the composition forms a layer of particles and binder having a thickness of approximately five to ten times greater than that of a layer of conventional antifouling paint, comparable to a "lining" of the shell . The very high proportion of overlapping particles makes it possible to obtain an attachment of the particles to each other, and therefore to avoid the dispersion of these particles in the environment.

After application to the surface intended to be treated, the coating composition forms a layer of nanoparticles and / or microparticles having a thickness of at least 600 microns, depending on the nature of the support (s) to be covered.

The resistance of the coating according to the invention is high over time, the latter not fearing an alteration in the air during drying of the treated surface, or immersion for several consecutive years. The intrinsic strength of this layer is also high, so that it is not damaged by any handling of the surface, for example a ship's hull, or other structure comprising the treated surface. The lifespan of such a layer can reasonably be compared to that of a boat itself. In the event of accidental degradation, the coating is easy to repair, by local reapplication of the product.

This layer can be revived, if necessary, by simple rubbing using a weakly abrasive household sponge, without drying the treated surface, and while respecting the environment.

[0053] According to a second aspect, the invention relates to a method for coating a surface comprising at least one step of applying to said surface a coating composition according to the invention.

[0054] Preferably, said method of coating a surface further comprises at least one step of drying said coating after said at least one step of applying to said surface.

Preferably, said at least one application step is carried out by cold metallization.

The cold metallization technique makes it possible, by associating nanoparticles and / or microparticles of metal with a binder, to cover any rigid or semi-rigid support, including porous ones. Said invention makes it possible to cover any substrate in order to obtain a result which is smooth to the touch while providing long-lasting antiseptic protection. The high content of nanoparticles and / or microparticles of copper and / or flat lamellar nickel, which overlap, allows perfect homogeneity between them and form a so-called “placoid” covering protection.

Preferably, said at least one cold metallization application step is carried out by means of a spray and / or a paint roller and / or a brush and / or by electrodeposition.

Preferably, said at least one application step is repeated until a coating with a thickness of at least 600 microns is obtained on the surface to be coated.

[0059] According to one embodiment, said method can comprise the application of a specific interface on the surface to be coated before the step of applying the coating composition according to the invention, allowing a more durable maintenance of this. last.

The supports in contact with the touch that cannot be dismantled or too heavy to transport will be directly protected on site with, as soon as they dry, direct protection without having to "revive or activate" the process.

The coating composed of nanoparticles and or laminated microparticles goes thanks to the binder ensuring a surface called "placoid scales" preventing any installation of viruses, microbes or air entrapment while releasing the antiseptic properties of the nanoparticles and / or microparticles of copper and / or nickel and / or metal in flat lamellar shapes.

To treat a surface of 10m ² a quantity of 965 grams of product is applied 96.5 g per m ² per applied layer, ie:

- 270 grams of particles of copper or an alloy of copper and nickel;

- 600 grams of demineralized water;

- 90 grams of epoxy resin and agent for curing this resin;

- 0.05 grams of a thixotropic agent.

After application, the polymerization of the epoxy resin causes evaporation of the order of 15% of this resin, ie 5.63 grams, and the demineralized water undergoes 100% evaporation, ie 600 grams; the net weight of the product applied and polymerized is therefore 116 g per m ² .

The composition of the dry product per m ² is therefore as follows:

- 90 grams of particles of copper or an alloy of copper and nickel, ie 94%;

- 9 grams of epoxy resin and polymerization agent for this resin, ie 6%.

According to a third aspect, the invention relates to the use of the composition for the biocidal coating of a surface according to the invention for coating a surface, porous or non-porous, chosen from: wood, composite, steel, aluminum , stainless steel, ferrocement, concrete, polyester, epoxy, pvc, carbon rigid or semi-rigid.

[0066] According to a fourth aspect, the invention relates to the use of the biocidal surface coating composition according to the invention for coating a boat hull.

DESCRIPTION OF FIGURES

[0067] [Fig 1]: Figure 1 shows a schematic example of application of a coating with metal balls, comprising the substrate, copper balls, and air bubbles, as found in the prior art, for example in document FR2894974.

[0068] [Fig 2]: Figure 2 is a microscopic view of spherical shaped copper balls.

[0069] [Fig 3]: Figure 3 is a schematic example of a lamellar coating according to the invention, the particles of which are flat, ovoid, and forms a "placoid scale" type coating.

[0070] [Fig 4]: Figure 4 is a microscopic view of flat lamellar nanoparticles of the "placoid scale" type, without binder. The flat, lamellar particles of the "placoid scale" type overlap.

EXAMPLES

[0071] Example 1:

In a test experiment, the coating composition according to the invention is prepared.

This composition according to the invention is then applied by means of the method according to the invention, comprising a cold metallization step, on the surface of a boat hull.

This boat hull coated with the coating composition according to the invention is then immersed for one month in sea water.

A second boat hull made of material identical to the coated one is also left for a month in sea water, near the first hull. At the end of this month, the boat hulls are compared, and it appears that the hull not coated with the composition according to the invention is in worse condition than that coated with the composition according to the invention. Indeed, there are marks reflecting the attack of living organisms (bacteria, algae, etc.) on the untreated hull, while the boat hull coated with the composition according to the invention is intact.

Claims

[Claim 1] A biocidal coating composition with a surface comprising flat layered metallic nanoparticles and / or microparticles of diameter less than 45 microns which overlap, suspended in a binder comprising:

- an epoxy resin;

- a thixotropic agent;

[Claim 2] Biocidal coating composition for a surface according to the preceding claim, characterized in that said metallic nanoparticles and / or microparticles are nanoparticles and / or microparticles of copper and / or cupronickel.

[Claim 3] Biocidal coating composition for a surface according to any one of the preceding claims, characterized in that it comprises between 10 and 95%, preferably between 40 and 95%, even more preferably between 55 and 95%, by total weight of the composition of said nanoparticles and / or microparticles.

[Claim 4] Biocidal coating composition for a surface according to any one of the preceding claims, characterized in that it comprises between 1 and 50%, preferably between 5 and 45%, even more preferably between 5 and 35%, by total weight of the composition of said epoxy resin.

[Claim 5] Biocidal coating composition for a surface according to any one of the preceding claims, characterized in that it comprises between 10 and 45%, preferably between 15 and 45%, even more preferably between 28 and 45%, by weight of said thixotropic agent.

[Claim 6] A biocidal surface coating composition according to any one of the preceding claims, characterized in that said thixotropic agent is colloidal clay consisting of a mixture of sodium, magnesium and lithium silicates.

[Claim 7] A method of coating a surface comprising at least a step of applying to said surface a coating composition according to any preceding claim.

[Claim 8] A method of coating a surface according to the preceding claim, characterized in that it further comprises at least one step of drying said coating after said at least one step of applying to said surface.

[Claim 9] A method of coating a surface according to any one of claims 7 and 8, characterized in that said at least one application step is carried out by cold metallization.

[Claim 10] A method of coating a surface according to the preceding claim, characterized in that said at least one application step by cold metallization is carried out by means of a spray and / or a paint roller and / or a brush and / or by electroplating.

[Claim 11] A method of coating a surface according to any one of claims 7 to 10, characterized in that said at least one application step is repeated until a coating with a thickness of at least is obtained. 600 microns.

[Claim 12] Use of the biocidal surface coating composition according to any one of claims 1 to 6 for coating a surface, porous or non-porous, selected from: wood, composite, steel, aluminum, stainless steel, ferrocement, concrete, polyester, epoxy, pvc, carbon rigid or semi-rigid.

[Claim 13] Use of the biocidal surface coating composition according to any one of claims 1 to 6 for coating a boat hull.