WO2025229061A1

WO2025229061A1 - Composition for anti-graffiti coating and method for preparing the composition

Info

Publication number: WO2025229061A1
Application number: PCT/EP2025/061840
Authority: WO
Inventors: Niels Ole Vesterager
Original assignee: O2 Tabs Desinfektion GmbH
Current assignee: O2 Tabs Desinfektion GmbH
Priority date: 2024-05-01
Filing date: 2025-04-30
Publication date: 2025-11-06
Anticipated expiration: 2026-11-01

Abstract

The present invention relates to a composition for coating a surface and protecting the surface against unwanted decorations. The coating comprises one or more polysaccharides with polar bonds, one or more polysaccharides with polar and ionogenic bonds, a rheology modifying chemical, a divalent or higher valent acid, a CO₂ forming alkaline, one or more surfactants, and optionally one or more preservatives.

Description

COMPOSITION FOR ANTI-GRAFFITI COATING AND METHOD FOR PREPARING THE COMPOSITION

FIELD OF THE INVENTION

The present invention relates to a composition for protecting surface from contamination of different types of painting and other non-desired decorations. Further, the invention relates to a method for preparing such a composition.

BACKGROUND OF THE INVENTION

As well in urban environment and as in more rural areas, contamination of surfaces with various types of paintings and other types of non-desired decorations such as graffiti, tagging etc. is a well-known problem.

Cases, where graffiti is produced with oil-based paint on surfaces of structure such as piers, fences, and so forth, are raised as social problems. In addition, since such graffiti cannot be removed easily, the removal requires tremendous labour and costs. The costs associated with cleaning surfaces from graffiti is estimated to be more than USD 12 billion for the United States alone. Hence, enormous costs are associated with handling nondesired decorations.

The demands for easy and quick graffiti removal have been increasing. For example, Japanese Patent application JP 2005-262134 A discloses that after the surface of a concrete structure to be treated is painted with a primer and a clear paint for intermediate coating, a topcoat of clear paint having a function to facilitate the removal of graffiti and poster is applied. Thereby, graffiti can be removed by attaching a cloth gaffer tape for packaging having been cut to a predetermined length to the surface with graffiti and firmly rubbing the cloth duct tape with hand, followed by forcefully peeling off the cloth duct tape.

However, since the graffiti removal as described above requires attaching the cloth duct tape for packaging having been cut to a predetermined length to the surface with graffiti, firmly rubbing the gaffer tape with hand, and then forcefully peeling off the duct tape for packaging, this causes a problem of low operability during the graffiti removal operation.

Hence, to inhibit attachment of graffiti, it has been proposed to form an anti-fouling coating film, for example by applying a paint containing silicone oil or wax onto those architecture surfaces, or by painting the surfaces with a reactive silicone-based resin paint. Moreover, a method has been proposed in which a surface treatment agent containing particular organopolysiloxanes is applied and spread over the coating surface of an automobile or the like to form a coating film enabling easy removal of fouling component attached thereto.

However, the reactive silicone resin-based paint and surface treatment agent as described above have the problems that their anti-graffiti performances decrease over time, and that when the materials are painted to large thicknesses by roller application or brush application, the coating films dried at normal temperature form cracks over time. Additionally, although these methods enable graffiti removal, graffiti itself is possible. Accordingly, problems occur that graffiti is drawn again after graffiti removal in many cases. In other words, the conventional techniques do not exhibit a function for suppressing "graffiti-drawing action" and hence have a problem that graffiti actions and removals are repeated.

US patent 5948545 describes a process for protecting a surface from non-desired contamination using a solution based on polysaccharides. However, the solution is difficult to prepare and heating is required to dissolve the ingredients.

Hence, there is a need for a composition for protecting surfaces from contamination that is easy to prepare on site and that provides good long-term protection of the surface from said contaminations.

SUMMARY OF INVENTION

An object of the present invention is to provide a product for protecting surfaces from contamination of different types of painting and other non-desired decoration which product is easy to prepare and apply to a surface.

Another object is to provide a product for protecting surfaces from contamination of different types of painting and other non-desired decoration, where the product provides long term protection when applied on a surface and is also easy to remove from the surface when required. In an aspect, the present invention relates to a composition for coating a surface, said coating comprising one or more polysaccharides with polar bonds, one or more polysaccharides with polar and ionogenic bonds, a rheology modifying chemical, a divalent or higher valent acid, a CO2 forming alkaline, one or more surfactants, wherein the composition is blended as a dry blend and wherein about 2-6 % of the blend can be mixed with water and react with the water to form the coating.

In the composition, the molarity between the divalent or higher valent acid and CO2 forming alkaline is such that the amount of CO2 forming alkaline in mol will always be equal to or higher than the divalent or higher valent acid. This serves to ensure that sufficient micro bubbles of CO2 are formed, which again serves to homogenize the mixture.

It has appeared that the composition according to the invention has a high adhesion on all surfaces and when the composition is applied on a surface, it does not appear like a gel, but appears more like a medium viscose rubber. The reason for this surprising effect is considered to be the adding of one or more divalent or higher valent organic acids which is believed to make cross-links between the functionally groups at the molecules of the saccharide. The acid should at least be divalent, but may also be trivalent, tetravalent, pentavalent or having an even higher valence. Thus, the stability and viscosity can be regulated by the added divalent or higher valent acid. The composition is made as a fast self-dissolving powder, dissolving without heat and stirring to prevent forming of lumps. The composition(s) are preferably dissolved in water in an amount of about 2-6 %, such as 3 - 5 % to form a liquid product or solution which may provide a thin transparent rubber layer or film on the surfaces and is very smooth and can easily be applied on the surfaces and gives a durable thin homogeneous surface. The compositions are stable against alkaline with a pH up to about 12 or even up to pH about 13. Moreover, the applied layers of the composition(s) are very easy to remove from surfaces together with the decontamination. The composition is dissolved in water relatively easy at ambient temperature, e.g. without applying any heat which makes the composition and dissolving in the liquid product easy to handle. The composition is a dry powder which is mixed with water in a mixing container. About 3 - 6 % of the dry powder is added to the water all at once while stirring vigorously such that a rotating water column or vortex is formed. The reason for this is to pull or drag at least at part of the powder down to the bottom of the mixing container to obtain a homogeneous mixture, as it is not possible to add anything later due to the consistency of the coating, which becomes so viscous during reaction with the water that the mixing container can be turned (180°) without the product “running out”.

When the mixture constituting the coating has stood for a few days, the CO2 has been absorbed into the water, and the mixture will become even more viscous and rubbery and can only be applied with special pumps for high viscosity.

The coating can also be laid out immediately after the CO2 evolution has ceased without any problems for the application as the CO2 is absorbed and leaves a perfectly smooth surface without the inclusion of CO2 bubbles.

The surface of the coating is "rub- resista nt" when the surface is dry, even if water is applied. The coating can be removed at low pressure < 25 bar and 50°C without additives.

The coating is washable with alkali and stable up to pH 13.

The coating can be pulled off as a solid "film" if the product is sprayed with water, preferably with a temperature about 50°C. The surface only needs to be made moist with cold water (tap water < 20°C). When the "film" is dry, it has a high strength/firmness/stiffness and does not break easily, but depending on the thickness.

The composition may comprise the ingredients in the following amounts. 20-50 % of one or more polysaccharides with polar bonds;

5-30 % of one or more polysaccharides with polar and ionogenic bonds;

5-20 % of a rheology modifying chemical;

10-40 % of a divalent or higher valent acid;

10-50 % of a CO2 forming alkaline;

2-10 % of one or more surfactants; and optionally 2-5 % of one or more preservatives. The use of preservatives is only required when the composition is stored as liquid for a longer period of time.

All percentages % mentioned are weight percentages (% w/w).

The ingredients are mixed to form a composition as a powdered mixture that has to be dissolved in water to form a coating before being applied to a surface. The composition(s) contain as major ingredient a mix of polysaccharides. At least one of the polysaccharides has chemical active functional groups. Moreover, the used polysaccharides are preferably all “cool” water dissolvable. The composition(s) also include a divalent or higher valent acid and a CO2 forming alkaline such as sodium bicarbonate. The molarity between acid and CO2 forming alkaline, the CO2 forming alkaline in mol will always be equal or higher than the acid. When the composition is dissolved in water, the divalent acids have two functions, 1 : making cross-links and 2: ensuring dissolving of the polysaccharides without lumping because of micro CCh-bubles.

The composition(s) can be dissolved in water to form a product which can be produced in situ and be applied to a surface after approximately 15-30 minutes.

When all the powder constituting the composition has been added fast to the water under vigorous stirring, the stirring can be stopped, and the powder will be dissolved automatically. The stirring is just for bringing the powder to the bottom of the water container, if not, it will lay on the top of the water and not be homogenously mixed with the water. When the stirring is stopped, the water with the dissolved composition will be filled with very small carbon dioxide bubbles. The viscosity of the solution is quite low in the beginning, because of the bubbles, and will increase during the time of standing. After some time most of the bubbles will be absorbed into the solution and the product will be free of bubbles.

Depending on the equipment used for applying the solution on surfaces, which can be a spraying device or a paint roller, the solution can be applied after 15 minutes when the powder is dissolving with bubbles (low viscosity) and after a couple of hours with higher viscosity and lower content of bubbles. After a couple of days, the solution is nearly free of bubbles. The result on the surfaces is the same thin film. The bubbles in the solution have no quality influence on the film coating of the materials. The film has a nice transparency effect and a good resistance against sun and rain which means a good longtime stability.

Another advantage is that the product dries fast and it is possible to lay more layers upon each other within the same working day.

The stability of the polysaccharides is good. Practical application on different surfaces shows that a layer with the composition lasts more than two years and is not damaged by sunlight, rain, minus temperatures and is not discolored

In an embodiment of the composition, the one or more polysaccharides with polarly bonds are selected from guar gum, konjac glucomannan, arabinogalactan, agar agar, karaya gum, locust bean bum, methyl cellulose, tara gum, tragant gum, gummi arabicum and/or a mixture of two or more of the polysaccharides.

In an embodiment of the composition, the one or more polysaccharides with polarly and ionogenic bonds are selected from algin acid, dehydroxanthan gum, xanthan gum, gellan, kappa-carrageenan, lota-carrageenan, lambda carrageenan, and/or a mixture of two or more of the polysaccharides.

The selected polysaccharides are easily accessible and they are soluble in water.

According to an embodiment of the composition, the rheology modifying chemical is preferably selected from deteareth-myristyl glycol, modified potato starch, acrylates copolymer, hydroxypropyl starch phosphate, acrylates/steareth-itaconate copolymer, acrylates/cetheth-itaconate copolymer, acrylates, aminoacrylates, C10-30 alkyl PEG itaconate copolymer or two or more of the mentioned rheology modifying chemicals.

The divalent or higher valent acid should be a part of the composition to affect the chemical reactions in the composition and preferably the divalent or higher valent acid is selected from oxalic acid, maleic acid, malic acid, tartaric acid, adipic acid, succin acid, citric acid, glutaronic acid, malonic acid, glutaric acid, a-aminoglutaric acid. The composition should also comprise CO2 forming alkaline and in an embodiment of the composition, the CO2 forming alkaline is selected from metal hydrogencarbonate and metal carbonate.

To increase the spreading and wetting properties of the composition, the composition includes one or more surfactants preferably selected from:

- nonionic surfactants with ethoxylaten from 10 -50, alky polyglucosides;

- anionic surfactants with sulphate and sulphonate group;

- cationic surfactants selected from didecyl dimethyl ammonium chloride, dialkylester ammonium methyl sulfat, benzyldimethyl ammonium chloride, methyl bis[ethyl (tallowate)]-2-hydroxyethyl ammonium methyl sulfate, myristalkonium chloride;

- amphoteric surfactant disodium cocoamphodiproprionate.

The product(s) can also contain a surfactant selected between nonionic, cationic or an anionic, or different metallic cation. The amount of nonion, cation or anion surfactant will change the character of the viscosity.

The change in viscosity can be performed by change in acid and sodium bicarbonate and the relationship between the polysaccharides. The formed film on the surfaces is not water dissolvable.

In case the composition shall be stored for a period after being dissolved in water, it is preferable to add one or more preservatives to the composition. Thus, in an embodiment of the composition, the one or more preservatives are preferably selected from bronopol, 2-methyl-2h-isothiazolin-3-one, benzisothiazolin-3-on, 5-chlor-2-methyl-2h-isothiazolin-3- on, 2-n-octyl-4-isothiazolin-3-on.

In an aspect, the invention also relates to a method for providing a product for coating a surface, where the method comprises the steps of:

- mixing one or more polysaccharides with polar bonds, one or more polysaccharides with polar and ionogenic bonds, a rheology modifying chemical, a divalent acid, a CO2 forming alkaline, one or more surfactants, optionally one or more preservatives to form a powdery composition;

- adding about 2 - 6 %, such as 3 - 5 % of the powdery composition to water and mixing briefly to distribute the powdery composition in the water;

- allowing the powdery composition/water mixture to react for about 10 to 30 minutes to form a liquid product.

When 2 - 6 % of the composition is added to water, some of the ingredients will react and form CO2 which will disappear eventually as the CO2 will form bubbles which will be absorbed in the water or disappear from the mixture. In the beginning, when the composition is added to water, the volume of water will increase with factor 2 to 3 until the CO2 is absorbed in the water, and the residue in the water will depend on the amount of the induvial ingredients in the composition which will be back in the film after application of the mixture to a surface. After a wash or rain, some components will be washed away and the residual film will be resistant against further water “attack”. Therefore, the amounts of the different chemicals in the dry composition will differ from chemicals in the liquid mixture and the formed film.

This is due to the fact that some chemical reactions appear when the composition is dissolved in water, such that the presence of the ingredients in the composition will differ from the ingredients in the mixture when the composition is dissolved in water and also for the ingredients in the formed film on the surfaces.

In an embodiment of the method, the powdery composition comprises

20-50 % of one or more polysaccharides with polar bonds;

5-30 % of one or more polysaccharides with polar and ionogenic bonds;

5-20 % of a rheology modifying chemical; 10-40 % of a divalent or higher valent acid; 10-50 % of a CO2 forming alkaline;

2-10 % of one or more surfactants; and optionally 2-5 % of one or more preservatives. When the powdery composition is dissolved in water, chemical reactions will appear including release of CO2, and the composition will change in the water. Preferably 2-6 %, such as 3 - 5 % of the powdery composition is added to water which is stirred for a short period of time to distribute the powder in the water for dissolving.

The invention will now be described with reference to some examples.

Example 1

A composition according to the invention was prepared from the below ingredients.

As polysaccharides with polarly bonds, a mixture of the polysaccharides guan gum and methyl cellulose was used and mixed with 50 % guar gum and 50 % methyl cellulose.

As polysaccharides with polarly and ionogenic bonds, a mixture of xanthan gum and guar gum was used and mixed with 45 % xanthan gum and 55 % guar gum.

25 % of the mixture of polysaccharides with polar bonds;

20 % of the mixture or polysaccharides with polar and ionogenic bonds;

8 % of deteareth-myristyl glycol;

15 % of oxalic acid;

28 % of natrium hydrogencarbonate;

4 % of didecyl dimethyl ammonium chloride.

A mixture was prepared of the composition and water such that the composition constituted approximately 5 % of the mixture. The mixture was stirred rapidly for a short time to distribute the powdered composition in the water. After stirring, the mixture was allowed to react for approximately 30 minutes.

After the reaction time, the liquid mixture was filled in a spraying device and sprayed onto a concrete wall, and approximately four square meters of the wall were covered with the mixture. The following procedure was followed for the application of the liquid mixture, a first layer of the liquid mixture was applied to the concrete wall, and the first layer was allowed to dry for about 45 minutes before a second layer of the liquid mixture was applied to the first layer. The coating was then allowed to dry and harden for approximately 24 hours before it was washed with water. The treatment resulted in a rubber-like thin transparent coating on the wall.

After six months, the coating was still attached to the wall and able to protect the wall against undesired painting. To test the function of the coating, about half a square meter of the coating was loosened from the concrete wall and removed. The coating was easy to detach from the wall and could be removed as a thin continuous film. The remaining part of the coating was left on the wall for testing for a longer time.

Example 2

In this composition, the polysaccharides with polarly bonds are selected from guan gum, agar agar, and methyl cellulose. Each of the polysaccharides were present in the mixture in an amount of about 33 %.

As polysaccharides with polarly and ionogenic bonds, a mixture of xanthan gum and inulin was used and mixed with 45 % xanthan gum and 55 % agar agar.

45 % of the mixture of polysaccharides with polar bonds;

10 % of the mixture or polysaccharides with polar and ionogenic bonds;

8 % of deteareth-myristyl glycol;

15 % of glutaric acid;

15 % of natrium hydrogencarbonate;

4 % of didecyl dimethyl ammonium chloride;

3 % of bronopol.

After preparation of the composition, the composition appeared as a powdered composition and the composition was mixed with water such that the composition constituted approximately 2.5 % of the mixture. The mixture was stirred rapidly for a short time to distribute the powdered composition in the water. After stirring, the mixture was allowed to react for approximately 30 minutes. After the reaction time, the liquid mixture was poured into a container and stored for approximately one month.

After the storing, the liquid mixture was transferred to a spraying device and sprayed onto a concrete wall, and approximately four square meters were covered with the mixture.

The coating was allowed to dry and harden for approximately 24 hours before it was washed with water. The treatment resulted in a rubber-like thin transparent coating on the wall After six months, the coating was still attached to the wall and able to protect the wall against undesired painting. A test as described in example 1 was also carried out and, as in example 1 , the piece of coating to be removed was easy to detach and remove from the concrete wall.

Claims

1. A composition for coating a surface, said coating comprising one or more polysaccharides with polar bonds, one or more polysaccharides with polar and ionogenic bonds, a rheology modifying chemical, a divalent or higher valent acid, a CO2 forming alkaline, one or more surfactants, wherein the composition is blended as a dry blend and wherein about 2-6 % of the dry blend can be mixed with water and react with the water to form the coating.

2. A composition according to claim 1 , wherein the molarity between the divalent or higher valent acid and CO2 forming alkaline is such that the amount of CO2 forming alkaline in mol will always be equal or higher than the divalent or higher valent acid.

3. A composition according to claim 1 or 2, where the one or more polysaccharides with polarly bonds are selected from guar gum, konjac glucomannan, arabinogalactan, agar agar, karaya gum, locust bean bum, methyl cellulose, tara gum, tragant gum, gummi arabicum and/or a mixture of two or more of polysaccharides.

4. A composition according to any one of the preceding claims , where the one or more polysaccharides with polarly and ionogenic bonds are selected from algin acid, dehydroxanthan gum, xanthan gum, gellan, kappa-carrageenan, lota-carrageenan, lambda carrageenan and/or a mixture of two or more of polysaccharides.

5. A composition according to any one of the preceding claims, where the rheology modifying chemical is selected from deteareth-myristyl glycol, modified potato starch, acrylates copolymer, hydroxypropyl starch phosphate, acrylates/steareth-itaconate copolymer, acrylates/cetheth-itaconate copolymer, acrylates, aminoacrylates, C10-30 alkyl PEG itaconate copolymer.

6. A composition according to any one of the preceding claims, where the divalent or higher valent acid is selected from oxalic acid, maleic acid, malic acid, tartaric acid, adipic acid, succin acid, citric acid, glutaronic acid, malonic acid, glutaric acid, -aminoglutaric acid.

7. A composition according to any one of the preceding claims, where the CO2 forming alkaline is selected from metal hydrogencarbonate and metal carbonate.

8. A composition according to any one of the preceding claims where the one or more surfactants are selected from:

- nonionic surfactants with ethoxylaten from 10 -50, alky polyglucosides;

- anionic surfactanta with sulphate and sulphonate group;

- amphoteric surfactant disodium cocoamphodiproprionate.

9. A composition according to any one of the preceding claims, where the composition further comprises one or more preservatives, said one or more preservatives preferably being selected from bronopol, 2-methyl-2h-isothiazolin-3-one, benzisothiazolin-3-on, 5- chlor-2-methyl-2h-isothiazolin-3-on, 2-n-octyl-4-isothiazolin-3-on.

10. A method for providing a composition for coating a surface, said method comprising the steps of:

- mixing one or more polysaccharides with polar bonds, one or more polysaccharides with polar and ionogenic bonds, a rheology modifying chemical, a divalent or higher valent acid, a CO2 forming alkaline, one or more surfactants, optionally one or more preservatives to form a dry powder product;

- adding about 2 - 6 % of the dry powder product to water and mixing briefly to distribute the powder product in the water;

- allowing the powder product/water mixture to react for about 10 to 30 minutes to form a composition.

11. A method according to claim 10, wherein the powdered product comprises

20-50 % of one or more polysaccharides with polar bonds;

5-30 % of one or more polysaccharides with polar and ionogenic bonds;

5-20 % of a rheology modifying chemical; 10-50 % of a CO2 forming alkaline;

2-10 % of one or more surfactants; and optionally 2-5 % of one or more preservatives.

12. A method according to claim 10 or 11 , wherein the dry powder is mixed with water in a mixing container, wherein 3 - 6 % of the dry powder is added to the water all at once while stirring vigorously such that a rotating water column or vortex is formed such that at least a part of the powder is pulled or dragged down to the bottom of the mixing container to obtain a homogeneous mixture in the mixing container.