DESCRIPTION

The present invention relates to products used for treating, cleaning and polishing stone elements. More in particular the invention relates to a cleaning composition for stone materials of natural and artificial origin

The cleaning of exposed stone material surfaces is mainly carried out through mechanical processes such as the process of "sandblasting", or through the use of acids.

With regard to the process of sandblasting, it consists of mechanical process by means of which the most outer part of a stone material is eroded, through the abrasive action of the jet of sand and air. This process is employed not only for the esterior cleaning of stone materials but also for the engraving of inscriptions and images on marble and stones. As already known, sandblasting presents a series of disadvantages.

A first problem of this process could be its abrasiveness, in which the removal of a superficial layer of the stone occurs.

However, a wrong execution of the process can also determine the detachment of whole parts of said materials.

Another problem of the process of "sandblasting" could be the dangerousness of the process itself. Infact, the high pressure of the jet of air and sand, can be a risk for the operator who carries out the sandblasting. Furthermore, the dusts developed during the process represent a risk not only for the operators but also for the people standing in close proximity, who could inhale said dusts.

Another problem of the process of sandblasting occurs when said process is employed for cleaning natural and artificial porous stones. Infact, this process can irremediably damage the surface of this kind of stones, determining the so-called "grater" effect.

An additional problem of sandblasting is the high noise of the machineries needed for the realization of the process.

Finally, one more disadvantage of the process of sandblasting is the high quantity of production waste produced during the process.

With regard to the cleaning treatment of stone material surfaces through the use of acid products, due to the abrasive action of these products, such a process can be potentially dangerous for the treated material.

The main object of the present invention is to solve the aforementioned problems of the cleaning methods for the surfaces of the stone materials. More particularly, object of the present invention is to supply a composition for the cleaning of stone material surfaces, which is not aggressive for the treated material and whose principle of action is not abrasive.

Another object of the present invention is to supply a high efficacy composition for the cleaning of stone material surfaces and whose use doesn't leave superficial rings or films at the end of the process. Another object of the present invention is to supply a composition for the cleaning of stone material surfaces that could be employed for eliminating moulds, soot and encrustations deriving from smog and hydrocarbons.

An additional object of the present invention is to supply a composition for the cleaning of stone material surfaces, whose use allow the processed stone to reacquire the original natural appearance.

A further object of the present invention is to supply a composition for the cleaning of stone material surfaces which doesn't represent a risk for operators involved in its use. Accordingly, the use of the composition object of the present invention does not require the use of skilled workers.

Another object of the present invention is to supply a non-toxic and biodegradable composition for the cleaning of stone material surfaces which does not produce waste at the end of the treatment.

An additional object of the present invention is to supply a composition for the cleaning of stone material surfaces of natural or artificial origin, with high porosity and not, for example "travertine" marble, bush hammered stone, stone benches, statues, monuments and monumental historical buildings.

Finally, one last object of the present invention is to supply a composition for the cleaning of stone material surfaces whose implementation does not require special tools and has a reduced implementation time. Furthermore, the composition object of the present invention will show high retention time (more than 24 months) if rightly stored in sealed storage units and far from heat sources. In addition, the same composition can possibly be produced directly on site.

The above-mentioned objects are reached by the composition for the cleaning of stone material surfaces composed of water, Sodium Bicarbonate, Ammonium Bicarbonate, Sodium Hydroxide, tetrasodium EDTA, and of a thickening, film-forming and stabilizing agent.

In addition, the above-mentioned objectives are also reached by the process for the preparation of a composition for the cleaning of stone material surfaces characterized by the steps of mixing water with Sodium Bicarbonate, adding and mixing Ammonium Bicarbonate to the mixture of water and Sodium Bicarbonate, adding and mixing Sodium Hydroxide to the mixture of water, Sodium Bicarbonate and Ammonium Bicarbonate, adding and mixing Tetrasodium EDTA to the mixture of water, Sodium Bicarbonate, Ammonium Bicarbonate and Sodium Hydroxide and adding and mixing the thickening, film-forming and stabilizing agent to the mixture of water, Sodium Bicarbonate, Ammonium Bicarbonate, Sodium Hydroxide and Tetrasodium EDTA.

This and other objects are reached by the composition for the cleaning of stone material surfaces according the present invention, which is herewith described, in one preferred embodiment non- limiting of other developments in the field of this patent.

The composition for the cleaning of stone material surfaces, object of the present invention, is made of a mixture of water, Sodium Bicarbonate, Ammonium Bicarbonate, Sodium Hydroxide, Tetrasodium EDTA and of a thickening, film-forming and stabilizing agent.

In a first embodiment of the composition, the thickening, film-forming and stabilizing agent is composed of carboxymethylcellulose sodium salt. The quantity of said agent inside the composition changes in relation to the desired viscosity for the composition and in relation to the surface to be treated. In a first embodiment of the invention, the composition for the cleaning of stone materials shows the following percentage by weight:

- 78,94 wt% of water,

2,63 wt% of Sodium Bicarbonate,

2,10 wt% of Ammonium Bicarbonate,

1,31 wt% of Sodium Hydroxide,

- 8,94 wt% of Tetrasodium EDTA,

6,05 wt% of thickening, film-forming and stabilizing agent.

In a different embodiment of the invention, the components have the following percentages by weight:

73,71 wt% of water,

2,45 wt% of Sodium Bicarbonate,

1,96 wt% of Ammonium Bicarbonate,

- 1 ,22 wt% of Sodium Hydroxide,

8,35 wt% of tetrasodium EDTA,

12,28 wt% of thickening, film- forming and stabilizing agent.

In a different embodiment of the composition, the thickening, film-forming and stabilizing agent used is composed of Benzalkonium chloride. In such a case, the volume percentage of the Benzalkonium chloride in the composition is of 1,8%, for example 550 ml in 30 litres of composition.

The process for the preparation of the composition for the cleaning of stone material surfaces according the present invention is herewith described. The process is characterized by the steps of:

Mixing water with Sodium Bicarbonate;

Adding and mixing Ammonium Bicarbonate to the mixture of water and Sodium Bicarbonate;

Adding and mixing Ammonium Bicarbonate to the mixture of water and Sodium Bicarbonate;

Adding and mixing Sodium Hydroxide to the mixture of water, Sodium Bicarbonate, Ammonium Bicarbonate and Ammonium Bicarbonate;

Adding and mixing Tetrasodium EDTA to the mixture of water, Sodium Bicarbonate, Ammonium Bicarbonate, and Sodium Hydroxide;

Adding and mixing the thickening, film-forming and stabilizing agent to the mixture of water, Sodium Bicarbonate, Ammonium Bicarbonate, Sodium Hydroxide and Tetrasodium EDTA. In this last step, the thickening, film-forming and stabilizing agent will be alternatively composed of Carboxymethylcellulose sodium salt or of Benzalkonium chloride.

As example, the above-mentioned method is now shown, applying some predetermined quantities of components, according the above described molar ratios. With regard to the mixing step of water and Sodium Bicarbonate, firstly the water is placed in a vessel suitable for the treatment of chemical materials, for example a polyethylene vessel. In addition, the hardness of the water used for the mixing has no important influence on the final product. In the first step, 30 litres of water are mixed with one kg of Sodium Bicarbonate. Said first step of mixing is carried out through the use of a mechanic or electric mixer till the complete dissolution of the salt inside the water. The whole duration of the mixing is function of the temperature of the liquid (water) and it is generally between 5 and 10 minutes at the standard temperature of 20 degrees Celsius.

0,8 kg of Ammonium Bicarbonate are added to the mixture just obtained. Similarly, this mixing step is carried out through the use of a mechanic or electric mixer till the complete dissolution of the Ammonium Bicarbonate inside the mixture of water and Sodium Bicarbonate. The whole duration of the mixing is function of the temperature of the liquid and it is generally between 5 and 10 minutes at the standard temperature of 20 Degrees Celsius.

Subsequently, 0,5 kg of Sodium Hydroxide (in scales or pearls) are added to the mixture and mixed, through the use of a mechanic or electric mixer till the complete dissolution of the Sodium Hydroxide. The whole duration of the mixing is function of the temperature of the liquid and it is generally between 5 and 10 minutes at the standard temperature of 20 Degrees Celsius.

Once completed this step, 3,4 kg of Tetrasodium EDTA are added to the mixture. The blend is then mixed through the use of a mechanic or electric mixer till the complete dissolution of the Tetrasodium EDTA. The whole duration of the mixing is function of the temperature of the liquid and it is generally between 5 and 10 minutes at the standard temperature of 20 Degrees Celsius.

Finally the thickening, film-forming and stabilizing agent is added to the mixture just obtained. This agent is alternatively made of carboxymethylcellulose sodium salt or of Benzalkonium chloride.

The quantity of said thickening agent changes in relation with the applicability requested by the composition, the viscosity of said agent and in function of the surface to be treated with the composition, subject of the present invention. As example, the quantity of the carboxymethylcellulose sodium salt added to the mixture is 3,6 kg in case said sodium salt has a medium viscosity, 2,3 kg in case the salt has a low viscosity and 5 kg in case of high viscosity.

The mixing step between the thickening agent and the mixture is carried out though the use of a eletric or mechanic mixer and has a duration between 10 and 15 minutes. In addition, this mixing step is repeated a second time for the total duration between 10 and 15 minutes, after at least one hour from the first mixing. In the end, this mixing is repeated after 24 hours for additional 10-15 minutes until making this blend homogeneous and without clots.

The composition object of the present patent application made of water, Sodium Bicarbonate, Ammonium Bicarbonate, Sodium Hydroxide, Tetrasodium EDTA, and of a thickening, film- forming and stabilizing agent can be used for the cleaning of stone material surfaces of natural or artificial origin.

The process of application of the above-mentioned composition, consists in a first step of preparation of the surface, in order to remove any possible solid residual as dust or soot. Then, through the use of a brush or a spatula, a thickness of at least 2 mm of the composition is added on the whole surface.

This thickness of product has to be covered by a transparent film of polyethylene or a different material with the same features.

The time duration of the composition changes between 12 and 24 hours, and, in case the ambient temperature is low, the time duration will be of at least 48 hours.

At the end of the process, the transparent coating film and the product must be removed through the use of a low-pressure water jet cleaner.