DESCRIPTION

Field of application of the Invention Patent

The present invention relates to a high-viscosity silicone-based coating adapted to temporarily cover the surface of, for example, bathrooms and toilets, in order to reduce water consumption and cleaning times of the sanitary ware.

The invention also relates to a spray can containing therein at least the above- mentioned high-viscosity silicone and a propellant.

Furthermore, the method relates to the method of applying the aforesaid water- repellent/release coating.

Background

Usually, dirt (faeces and urine drops) that is not immediately removed from toilet surfaces tends to dry out and significantly adhere to those surfaces; over time, removal becomes difficult because water cannot penetrate the interface between the ceramic and the dehydrated solid dirt. This makes the cleaning operation more time-consuming and requiring more water and detergents, with the inevitable environmental consequences.

One of the possible solutions to this problem is to coat the inner surface of sanitary ware (bathrooms and toilets) with a water-repellent film in order to have dirt slide down the drain more effectively, preventing waste from sticking to the surface encrusting it, thus saving water and time for cleaning operations. There are, in the prior art, several methods for applying such a water-repellent film: for example, one method is known wherein the surface of a ceramic product is coated with siloxane resins containing an alkyl fluoride group in order to lower the surface tension of the ceramic. However, such applications can only be carried out at an industrial level during the production of the artefact, as described, by way of example, in the South Korean Invention Patent KR20130106580, filed on 20/03/2012 in the name of PARK JUNG HO (KR) (Title: “Method for forming an inner coating layer of a urinal to save flushing water”), wherein the inner coating layer of the urinal adapted to reduce flushing water use comprises the following steps: selecting a urinal and washing mainly the inner surface thereof; polishing the inside of the urinal and removing contaminants using a polishing machine and polishing material; washing and drying the polishing material and contaminants from the polishing process; applying a coating material to the inside of the washed urinal and forming a hard coating layer; and drying the inside of the urinal formed with the coating layer.

Various materials can be used as a coating agent, but in the proposed invention this material is mainly composed of silane (SiH4), siloxane (siloxane, H3Si-(OSiH2)n-OSiH3) and a small amount of chelate, with the silane and siloxane containing 62-72% of silicon.

As already mentioned, this is an industrial process; the application is done by spraying or brushing, but once the curing operation is complete, the result will be that of a permanent coating, which inevitably loses its effectiveness over time.

There are also in the state of the art temporary applications, such as the SPOTLESS® spray produced and marketed by the US company SPOTLESS MATERIALS INC. (cf. website https://spotlessmaterials.com/products/toilet- coatinq); the spray in question is applied to the inner surface of the toilet, instantly creating a nano-coating that acts like a tiny sponge that retains the liquid lubricant. The super-slippery layer reduces the adhesion of sticky liquid, mineral or solid deposits to the surface, facilitating cleaning operations. The lubricating layer is degraded after a few washes, actually making the applied nano-film temporary.

In the relative reference (European) Patent EP3966291 , filed on 14/09/2020 (with US priority US201962900207P dated 13/09/2019; Title: “Formulations and processes to generate repellent surfaces”) it is disclosed a formulation for the preparation of repellent coatings on substrate surfaces including: (i) one or more reactive components that can form a bonded layer on a surface wherein the bonded layer comprises a matrix of compounds, each compound having one end bonded to a surface and an opposite end extending away from the surface; (ii) an optional catalyst; (iii) a solvent; and (iv) a lubricant. A repellent coating may be formed from such formulations on the substrate surfaces by drying the formulation on the surface to substantially remove the solvent and to form a bonded layer on the surface with the lubricant firmly adhered to the bonded layer. The formulations can be applied to surfaces made of ceramics, glass, metals, alloys, composites, polymers or combinations thereof such as ceramic or metal sanitary ware, surfaces of glass substrates including mirrors, windshields, windows, surfaces composed of one or more polymers, medical materials (devices such as ostomy devices), etc. Specifically, solvents may include a lower ketone, lower alcohol, lower ether, lower ester, lower halogenated solvent and combinations thereof, while lubricants may include a silicone oil or mineral oil or vegetable oil or any combination thereof. Other components may be included in the described formulations, such as a fragrance.

As it can be seen, silicone, which is the main component of the water-repellent coating that will be described shortly, is also present in the document just described, but only as a secondary component of the lubricant; the result is a water-repellent film that is indeed temporary, but whose effectiveness, given its low viscosity, is rather poor.

Summary of the Invention Patent

The water-repellent and release coating subject of the present invention is intended to overcome the problems described in the state of the art, as it can be used on all installed and manufactured ceramics, particularly on the inner surfaces of bathrooms and toilets; it can also be easily applied in any type of environment for both large structures and home use. In addition, such a coating with a release effect can also be used on the inner surfaces of moulds, particularly for moulding plastics, in order to facilitate the release of the moulded part from the mould itself.

The main component of the coating is a high-viscosity single-component silicone and the best application method is by spray can. The diluting action is thereby provided not only by the solvent used to dilute the silicone (e.g. alkanes, cycloalkanes or the like), but also by the propellant (liquefied hydrocarbons such as butane propane, dimethyl ether, etc., or even compressed gases such as CO2 and N2...) present in the spray can.

High-viscosity silicone is a rubbery material that has an advantageous tendency to self-repair and level even in spots where there may have been some small mechanical removals. Specifically, silicone is a polymer that contains a silicon atom combined with carbon, hydrogen and oxygen; sometimes other complementary groups may also be added.

In the above-reported figure, POLYDIMETHYL SILOXANE, i.e. the silicone oil used in this coating, where the silicon-bonded groups are METHYLS, is shown. The number n describes the length of the polymer chain (or the degree of polymerisation). As n increases, the viscosity of the product increases from 0.65 cSt (centiStokes) or mm ² /s to over 20,000,000 cSt or mm ² /s.

According to the invention, the viscosity value of the POLYDIMETHYL SILOXANE silicone, or mixture of silicones used for this invention, is at least 500,000 cSt (centiStokes) or mm ² /s, preferably above 20,000,000 cSt or mm ² /s.

This viscosity measurement is carried out using the methodology defined in DIN 53019.

Thanks to the application of this new invention, whose method of choice is, as already mentioned, by spray can, a hydrophobic (water-repellent), coloured and transparent film, which has a release/anti-adhesive effect against faeces and liquids, is deposited on the surface of the toilet (or other similar surfaces). More specifically, in the case of liquids, the droplets tend to slide directly into the bottom of the toilet, thus not drying out and releasing unpleasant smells; in the case of faeces, cleaning, even after a long time, is mechanically facilitated and therefore easier and faster. These effects are advantageously due to the fact that, using this invention, the adhesion force between the dirt and the film is very low: this allows to quickly remove, both immediately and even after some time, the dried product.

Another relevant aspect is that any residues tend to spontaneously disintegrate and be removed during subsequent rinse cycles.

The use of this invention therefore makes it possible, compared to what existing on the market, to reduce:

- cleaning times by the personnel;

- the consumption of washing water, as well as

- the use of aggressive detergents. In particular, saving cleaning water takes place upstream and the nondispersion of aggressive surfactants into waste water is a direct consequence thereof. These are two important factors in an ever-increasing effort to protect the environment in terms of both water saving and the discharge of pollutants into waste water.

The application by spray can is the most effective and performing, but the product can also be used in other ways, such as spraying, brushing or dabbing.

The product therefore requires only one application; the surface is active and functional after about 5-10 minutes. The deposited film is not permanent, as it can be easily removed by mechanical action or using detergents. The use of such a product allows to reduce consumption of water and aggressive detergents, as well as reduce the time for cleaning.

As mentioned above, the invention also relates to the spray can which comprises therein (filled with) a first predetermined amount of POLYDIMETHYL SILOXANE silicone, with a viscosity grade of at least 500,000 mm ² /s, preferably higher than 20,000,000 mm ² /s, and a second predetermined amount of propellant. The spray can thus constituted is advantageously configured to allow a water-repellent/release coating according to the invention to be applied to an inner surface of a toilet or any other type of surface of any element.

Preferably, the propellant is a liquefied hydrocarbon, such as butane propane and dimethyl ether, or alternatively a compressed gas, such as carbon dioxide and diatomic nitrogen.

According to the preferred embodiment of the invention, a third predetermined amount of solvent is also placed inside the spray can of the invention. Preferably, this solvent is selected from alkanes, cycloalkanes or the like.

According to the preferred embodiment of the invention, the composition within the spray can is the following:

- POLYDIMETHYL SILOXANE silicone, with a viscosity grade of at least 500,000 mm ² /s, preferably higher than 20,000,000 mm ² /s, 0.1 to 10%;

- solvent from 20 to 60%;

- propellant from 40 to 70%.

Finally, active ingredients can be added into the spray can to give it a perfume, sanitising, disinfecting and covering power. The invention also relates to the method of applying the water- repellent/release coating of the invention.

This method provides in particular the following steps: a) thoroughly cleaning the surface onto which said water-repellent/release coating is to be applied; b) applying the water-repellent/release coating (3) onto the surface using a spray can containing POLYDIMETHYL SILOXANE silicone, with a viscosity grade of at least 500,000 mm ² /s, preferably higher than 20,000,000 mm ² /s, and a propellant, so that the solvent action is also provided by the propellant of the spray can itself; c) waiting for at least five minutes before using said surface to allow the dilution solvents present in said silicone to evaporate, allowing the formation of said water-repellent/release coating.

Preferably, the step a) is carried out using detergents in order to completely remove the residues present on said surface.

Again, according to the preferred embodiment of the invention, the step a) of cleaning the surface is followed by an additional step of drying and removing moisture from the surface with a dry cloth.

Finally, the product can be added with active ingredients that give it a perfume, sanitising, disinfecting and covering power.