WO2012066172A1

WO2012066172A1 - Water-repelling ceramic enamel having a metallic sheen and method for producing same

Info

Publication number: WO2012066172A1
Application number: PCT/ES2011/070781
Authority: WO
Inventors: José Francisco FERNÁNDEZ LOZANO; Julián JIMÉNEZ REINOSA; Juan José ROMERO FANEGO; Vicente Orta Bolea; Pedro José JAQUOTOT GARCÍA; Miguel Ángel BENGOCHEA ESCRIBANO
Original assignee: Consejo Superior De Investigaciones Científicas (Csic); Kerafrit, S.A.
Priority date: 2010-11-15
Filing date: 2011-11-14
Publication date: 2012-05-24
Also published as: ES2382514A1; ES2382514B1

Abstract

The present invention relates to a composition based on metal oxides and clay, used in an aqueous suspension for forming a ceramic coating. The invention further relates to a method for producing enamelled materials having a metallic sheen and strong water-repellent properties.

Description

HYDROPHOBIC CERAMIC ENAMEL WITH METAL BRIGHTNESS AND ITS PROCESSING PROCEDURE

The present invention relates to a composition based on metal oxides and clay, which is used in an aqueous suspension for the formation of the ceramic coating, in addition the invention relates to a process for obtaining enameled materials with metallic luster and high hydrophobic character.

STATE OF THE PREVIOUS TECHNIQUE

Enamels with metallic appearance have been traditionally used due to the metallic reflections and iridescences they produce. The artisanal processes of obtaining enamels with metallic reflections known as Lustres date from the Middle Ages and the Renaissance. These handmade lustres require temperatures below 700 ° C in reducing atmospheres to generate a high local concentration of metal nanoparticles in a vitreous melt [J. Am. Ceram. Soc. 84,2,442-446,2001]. These production processes are unfeasible for current industrial ceramics.

Industrially, metal lustres are based on noble metals that require third-fire cooking generally limited to temperatures below 1000 ° C. The procedures for obtaining lustres based on noble metals are remarkably expensive due to the high price of noble metals and the need for a new treatment or third fire for their application. Lusters with metallic appearance do not constitute a vitrified surface and thus their technical properties are not suitable as they present ease of wear and low resistance to chemical agents.

Other processes for obtaining metallic-looking ceramic surfaces have recently been claimed by means of the vapor phase deposition to obtain ceramic tiles, floor and wall tiles with metallic appearance [EP1498402]. The metallic appearance obtained is a consequence of a coating of a metallic layer of elements such as chromium, zirconium, tantalum, titanium and nitrides or carbides of said elements. The procedure implies a high cost since it requires vacuum bells for application on tiles that have been previously produced. The limitations of the technique in addition to its high costs are based on the impossibility of obtaining the decoration of the pieces beyond the metallic coating.

A recent process for obtaining ceramic surfaces with a metallic appearance consists in the incorporation of particles smaller than 100 μηι from metals or metal alloys with melting points greater than 1 100 ° C [EP1702896]. The aforementioned procedure has as a main limitation the requirement to polish the ceramic surface after the cooking process to obtain the metallic appearance generated by the polished metal particles. The polishing process implies a high cost that is generally even higher than the production cost of the base material. Additionally, the incorporation of metallic particles presents important rheology problems that result in low stability and homogeneity of the enamel slippers.

The industrial development of metallic effects in ceramic tiles has been proposed from mixtures of essential oxides such as S1O2, AI2O3, Fe2Ü3 and P2O5 together with certain optional oxides, namely: CaO, MgO, Na ₂ 0 and K ₂ 0 [WO 01 / 72651]. This formulation is characterized by being free of noble metals, by being applied in ceramic tiles and baked in an industrial cooking oven between 1 100-1250 ° C and by having a high content of Fe2O3 and P2O5, in the range 10-30% and 7 -27% by weight respectively. An improvement of procedures related to formulations for metallic enamels and high contents Phosphate is the use of Fe30 ₄ as a precursor, since it extends the temperature range for use by incorporating fluxes such as PbO and has advantages for the removal of iron contaminants [ES 2301364]. The limitations of the technique for metallic-looking enamels using compositions with phosphates and iron oxides are multiple, since they present problems of application due to the rheological characteristics of the materials used that result in lack of homogeneity, appearance of defects and low temperature stability A simplification of these problems occurs when a previous process of synthesis of pigments based on iron phosphates with Fe ₂ 0 ₃ and P ₂ 0 ₅ contents is performed, in the range of 40-70% and 10-50% by weight respectively [ES 2246 166]. This procedure minimizes the rheological problems of raw materials and frits that contain iron oxides and phosphates. The use of these pigments is favorable for their application and allows their use to be extended to temperatures up to 1250 ° C, as required in the production of sanitary ware. The process of obtaining a pigment implies an increase in production costs because it is an additional thermal process at a temperature between 400 and 1200 ° C, but the high price of phosphate precursors is not resolved.

Metallic-looking enamels as a whole have limitations due to:

- The high cost of raw materials, mainly phosphate precursors;

- The absence of brightness of phosphate-based enamels attributed to the presence of micrometric crystals on the surface that produce diffuse reflection of light, which is why its limitation is limited to surfaces with textures to obtain an apparent sensation of brightness; - The difficulty in controlling the formation of phosphate phases at high temperature;

- The high solubility of phosphate glasses in aqueous medium. An artisanal alternative to obtain enamels with a metallic appearance is the use of highly melting enamels based on iron oxides and commonly known as venturin enamels. This type of enamels are of application at low temperature and its main characteristic is to have in suspension floating iridescences caused by the crystallizations of hematite. Multiple artisan recipes have been described that include different metal oxides in the formulation, including the use of CuO in a composition high in PbO. Venturin enamels enhance their aesthetic properties when obtained in reducing atmospheres. The limitations of the technique for the development of industrial ceramic metallic enamels are obvious to one skilled in the art, with reproducibility being the most limiting factor.

A process for obtaining metallic enamels for industrial applications based on CuO in lead-free enamels has been published recently [J. Am. Ceram. Soc. 92 [1 1] 2784-2790 (2009)]. The enamels are obtained by fritting compositions with 26% by weight of CuO and a high percentage of fluxes, 5% boron weight and 16% by weight of Na2O. The result is an enamel with an inhomogeneous metallic appearance with dark areas that have no luster effect. The enamel surface has crystallizations on the surface in the micrometric range of tridymite, SiO ₂ , metallic Cu and tenorite, CuO. Such crystallizations are not homogeneous and the appearance of metallizing is difficult to control due to the presence of different regions in the tiles. A process for developing bright metallic-looking tiles [WO2008 / 152174] has recently been developed based on the incorporation of dispersed and anchored metal nanoparticles in sepiolite clay nanofibers [ES200302396 / 8]. In this procedure, ceramic glazes with metallic luster are obtained from metallic particles or alloys of micro / nanometric size and / or by particles of different oxides that have a metallic character in the optical range (Fe ₃ 0 ₄ , Co ₃ 0 ₄ , NbO , TaO, Mn ₃ 0 ₄ , Mo _x O _y and W _x O _y ) or precursors that allow obtaining the previous conductive oxides. These bright metallic enamels are also characterized by having a nanostructure on their surface that allows them to have a hydrophobic response with wetting angles for water of 95 ° \ Bol. Soc. That. Ceram V. 48, 2, 95-98 (2009)]. The procedure requires that the supported metal nanoparticles rise to the surface to form a microstructure similar to that of the Lotus Flower type. The limitations of the described procedure are because it requires the addition of a reducing agent, eg coal dust, necessary for the local and transient reducing atmosphere to be generated during the cooking process that preserves the metal nanoparticles. Another of the limitations presented by the technique is the formation of surface defects due to crystalline growths of CuO of micrometric size that give rise to the formation of a characteristic veil that reduces brightness and hydrophobic response. These defects have a narrow temperature range in which they can be controlled, an aspect that specifically requires adjusting the composition for each oven. The processing of metallic nanoparticles implies a high cost that in practice prevents this type of shiny metallic enamels from being competitive in the market. DESCRIPTION OF THE INVENTION

The present invention provides a composition that in an aqueous suspension by means of a coating process produces an enamel of metallic and hydrophobic luster, useful for its applications in ceramic materials.

A first aspect of the present invention relates to a composition characterized in that it comprises a copper oxide, a fried glass, a clay, and at least one metal oxide that is selected from Fe ₂ 0 ₃ , Mn0 ₂ , ZnO, CoO, NiO, Cr ₂ 0 ₃ , Zr0 ₂ , Ce0 ₂ , Al ₂ 0 ₃ , Si0 ₂ or any combination thereof (hereinafter composition of the invention).

In a preferred embodiment the composition of the invention further comprises a ceramic pigment. And in a more preferred embodiment the percentage by weight of the ceramic pigment is between 1 to 10% with respect to the total weight of the composition. These ceramic pigments can have spinel structure.

Preferably the weight percentage of copper oxide is between 5 to 22% with respect to the total weight of the composition.

In a preferred embodiment the weight percentage of the clay is between 3 to 14% with respect to the total weight of the composition. In another preferred embodiment the percentage by weight of the metal oxides between 1 to 10% with respect to the total weight of the composition.

Preferably the weight percentage of the fried glass is between 50 and 85% with respect to the total weight of the composition.

The frit may comprise oxides that are selected from Si0 ₂ , Al ₂ 0 ₃ , CaO, PbO, ZnO, Na ₂ O, K ₂ O, MgO, B ₂ O ₃ , BaO, CuO, Fe ₂ O ₃ or any of your combinations The percentage by weight of said oxides with respect to the total weight of the frit can be as detailed in table 1: Composition range

Oxide

(% in weigh)

SiO ₂ 40% - 70%

AI ₂ O ₃ 4 - 12%

CaO 5 - 16%

PbO <10%

ZnO 3 -10%

Na ₂ O 1 -10%

K ₂ O 0.5 - 4%

MgO 0.5 - 3%

B ₂ O ₃ 0.5 - 6%

BaO <5%

Table 1: Percentage by weight of the oxides with respect to the total weight of the frit.

Other components can be found in the frit in a content less than 1% by weight with respect to the total of the frit, as for example and expressed in its equivalent oxides CuO, Fe ₂ O3 or P ₂ Os.

In a preferred embodiment the size of the copper oxide particles, the metal oxides and the pigment is less than 63 μηπ. In a more preferred embodiment the size of the copper oxide particles, the metal oxides and the pigment is less than 30 μηπ. And in a more preferred embodiment the size of the copper oxide particles, the metal oxides and the pigment is less than 15 μηπ. Preferably the clay is at least one phyllosilicate or any of its mixtures. More preferably the phyllosilicate is at least one kaolinite. And More preferably the phyllosilicate has a composition comprising the elements that are selected from SiO ₂ , AI ₂ O 3, CaO, Na ₂ 0, K ₂ 0, MgO or any combination thereof.

The composition of the oxides of said clay can be the one detailed in table 2.

Table 2: Weight percentage of the oxides that make up the clay with respect to the total weight of the clay.

In the present invention, when reference is made to a metal oxide, no restriction is established regarding its oxidation state and even precursors of said oxides can be used.

The composition of the invention is advantageous for producing bright and hydrophobic metallized enamel in a wide range of temperatures.

In a second aspect, the present invention relates to the use of the composition of the invention, as an enamel for ceramic coating, as for example in sanitary porcelain enamels. In a preferred embodiment the ceramics are tiles, bricks, tiles, sanitary ware, flooring or decorative elements.

A third aspect of the present invention relates to an aqueous suspension characterized in that it comprises the composition of the invention.

In a preferred embodiment the content of the composition of the invention is less than 70%.

The clay of the composition of the invention allows a good suspension in aqueous medium of the different components of the composition.

Preferably the aqueous suspension of the present invention further comprises at least one additive that is selected from thickener, dispersant, preservative or any combination thereof. More preferably the thickener is carboxymethyl cellulose. And more preferably the dispersant is sodium tripolyphosphate.

In a fourth aspect the present invention relates to the use of the aqueous suspension as described above, for the manufacture of enameled materials.

A fifth aspect of the present invention relates to a process for obtaining the aqueous suspension described above comprising homogenization in aqueous medium of the ceramic composition.

In a preferred embodiment the homogenization is performed in a ball mill.

Another aspect of the present invention relates to an enameled material characterized by comprising the composition of the invention and a ceramic support. The enameled material has a homogeneous coating of the composition of the invention.

In a preferred embodiment the enameled material is characterized by having a brightness greater than 63% in direct reflection and greater than 50% in diffuse reflection.

This percentage of reflection is an advantage over the materials obtained using metal nanoparticles [WO 2008/152174] that reach values of 58% in direct reflection and 47% in diffuse reflection. The appearance of defects of surface crystallizations in the form of a veil reduces the percentage of brightness achieved up to 54% in direct reflection and 41% in diffuse reflection. By comparison, a tile that has a colored crystalline frit of a similar tone to that of a metallic tile only reaches a brightness percentage of 54% in direct reflection and 37% in diffuse reflection. These data imply that the gloss metallic enamels obtained following the process of the present invention are clearly advantageous from the point of view of brightness.

On the other hand, the incorporation of metallic oxide and / or ceramic pigment causes a modification in the chromatic coordinate maintaining a good hydrophobic response, achieving as for example, but without limitation, gray, gold, green, bluish, red or yellow.

In another preferred embodiment the enameled material is characterized by comprising a hydrophobicity with an angle of contact with water greater than 90 °, and in a more preferred embodiment the material has a hydrophobicity with an angle of contact with water greater than 1 10 ° . This wetting angle value represents an advantage over the materials obtained using metal nanoparticles [WO 2008/152174] that reach values of 90 °. The appearance of defects of superficial crystallizations in the form of a veil reduces the contact angle to values of 50 °. By comparison, a tile that has a colored crystalline frit of a similar tone to that of a metallic tile only reaches a contact angle value of 35 °. These data imply that the gloss metallized enamels obtained following the process of the present invention possess advantageous hydrophobic characteristics.

The improvement in brightness and hydrophobicity of the surfaces obtained following the process of the present invention, are based on the control of the tenorite (CuO) crystallizations on the surface. Crystallizations on the surface occur in the form of submicron crystallizations, preferably nanocrystals. The set of crystallizations form a characteristic cell-like structure.

Preferably the enameled material is characterized by having a surface roughness of less than 500 nm, more preferably the roughness of the enameled material is less than 100 nm. This surface structure consists of a cell-type microstructure with nanostructure that is responsible for the hydrophobic response.

The present invention comprises a formulation and the suitable application process that allows to maintain the crystallizations of CuO within the defined limits. The use of the fluxes incorporated in the frit and the adjustment of their proportions in relation to the percentage of copper oxide used thus represent an advantage over other embodiments referred to in the prior art.

Another aspect of the present invention relates to a process for obtaining the enameled material described above, comprising the steps: a) depositing the aqueous suspension described above on a ceramic support, and b) thermally treat the product obtained in (a) at a temperature between 900 and 1280 ° C. This temperature will depend on the composition of the frit.

Preferably the ceramic enamel has a thickness between 40 to 1000 μηπ.

The deposition of step (a) can be any of both the wet and dry ways, known to any person skilled in the art. In the present invention by way of example, but without limitation the methods of deposition of step (a) can be selected from a method of hood, veil, disc, spray, immersion, granules, electrostatic deposition, thermal projection, or by using inks for deposition by airbrushing, screen printing or pad printing,

In another preferred embodiment the heat treatment of step (b) is in an oxidizing atmosphere.

Another aspect of the present invention relates to the use of the enameled material described above as a covering or decorative element, floors, walls, on building facades, both interior and exterior, or in any other unconventional ceramic application, such as in environments urban, furniture, sanitary, and applications in technical ceramics among others.

Throughout the description and the claims the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and features of the invention will be derived partly from the description and partly from the practice of the invention. The following examples and drawings are provided by way of illustration, and are not intended to be limiting of the present invention. DESCRIPTION OF THE FIGURES

Fig. 1. Photograph of a tile with a bright and hydrophobic metallic appearance.

Fig. 2. Micrograph by Optical Light Microscopy Reflected from the surface of a bright and hydrophobic metallic-looking tile showing the characteristic surface pattern.

Fig. 3. Micrograph by Scanning Electron Microscopy of Field Effect showing the submicron crystallizations of tenorite on the surface of a bright and hydrophobic metallic-looking tile. Fig. 4. X-ray diffraction diagram showing the characteristic peaks of tenorite crystallizations, CuO, on the surface of a bright and hydrophobic metallic-looking tile.

Fig. 5. a) Image obtained by Atomic Forces Microscopy showing the surface roughness of a glossy and hydrophobic metallic-looking tile, b) surface roughness of the black line of figure (a), c) detail of the roughness of a cell of the pattern formed on the surface, d) roughness of the white line of figure (c) in which it is shown that the roughness of the surface inside a cell of the pattern formed on the surface is lower at 50 nm EXAMPLES

The invention will now be illustrated by tests carried out by the inventors, which demonstrates the specificity and effectiveness of the process for obtaining enameled materials with the composition of the invention. Example 1.- Procedure for obtaining metallic enamels with gloss and hydrophobes for porcelain stoneware ceramic flooring. Obtaining a glossy and hydrophobic metallic enamel on a porcelain stoneware substrate. To perform this process the following formulation is used in percentages by weight with respect to the total weight: a) 10% by weight of copper oxide (CuO),

c) 77.4% by weight of a frit, and d) 9.6% by weight of a clay.

In said formulation, the frit has a composition expressed as a percentage in oxide equivalent with respect to the total of: a) 50.6% of equivalent SiO ₂ , b) 9.70% of equivalent CuO, c) 6.5% of equivalent CaO, d) 6.3% of equivalent AI2O3, e) 6.0% of equivalent PbO, f) 6.0% of equivalent Na ₂ O, g) 4.4% of equivalent ZnO, h) 4, 1% of equivalent Fe2O3, i) 1, 9% of equivalent K ₂ O, j) 1, 7% of equivalent B2O3, k) 1, 2% of equivalent MgO, and I) 1, 58% of other minor components such as ΤΊΟ2, P2O5, Sn0 ₄ , BÍ2O3, or WO3, in a concentration of less than 1% each;

The above formulation is homogenized in aqueous medium at a concentration of 60% by weight solids content. To this mixture is added 0.2% by weight of a carboxymethyl cellulose type glue, 0.25% by weight of a tripol sodium phosphate dispersant and 0.05% by weight of an Additive type preservative. The mixture is homogenized by milling in alumina ball mill to constitute a stable suspension. The deposition of this suspension was performed by an airbrush on the ceramic support of porcelain paste with a variable thickness from 50 μηι to 1000 μηπ.

The enamel deposited on the support was heat treated at a temperature of 1200 ° C in an oxidizing atmosphere in a fast-cooking monostrate oven. As a result, a vitreous coating of metallic appearance on the porcelain stoneware support was obtained. This metallic-looking enamel is characterized by high gloss and hydrophobic response.

Example 1 was repeated but in this case the composition was carried out using a mixture of frits with different functionality such that it maintains the previously described composition. The rest of the process was continued according to example 1. It is noted that the results were reproduced and as an advantage it is observed that the mixture of different frits favors the adjustment of the composition.

Example 1 was repeated but in this case once the suspension was prepared, it was deposited on the substrate by bell. The rest of the process was continued according to example 1. It is noted that superior gloss results were obtained in this case as well as a smaller number of surface application defects. Example 2.- Procedure for obtaining metallic enamels of blue with gloss and hydrophobes for porcelain stoneware ceramic flooring.

Obtaining a glossy and hydrophobic metallized enamel on a blue porcelain tile substrate following a formulation similar to that used in Example 1 but instead of adding 4% by weight Fe ₂ O3 in the formulation 1% was added in Fe ₂ O3 weight and 2.5% by weight of a cobalt blue pigment based on cobalt aluminate, ZnAI ₂ O ₄ . The rest of the procedure remains the same.

As a result, a vitreous coating of metallic appearance and blue color was obtained on the porcelain stoneware support. This metallic-looking enamel is characterized by high gloss and hydrophobic response.

Example 3.- Procedure for obtaining metallic enamels of green with gloss and hydrophobes for porcelain stoneware ceramic flooring.

Obtaining a glossy and hydrophobic metallic enamel on a porcelain stoneware substrate. To perform this process the following formulation is used in percentages by weight with respect to the total weight: a) 10% by weight of copper oxide (CuO), b) 4% by weight of ZnO, c) 77.4% by weight of a fried and d) 9.6% by weight of a clay.

In said formulation, the frit or combination of frits have the following composition expressed as a percentage in oxide equivalent with respect to the total of: a) 50.6% of SiO ₂ equivalent, b) 9.70% of equivalent CuO, c) 6.5% of equivalent CaO, d) 6.3% of equivalent At ₂ 0 ₃ , e) 6.0% of equivalent PbO, f) 6.0% of equivalent Na ₂ 0, g) 8.4% of equivalent ZnO, h) 1, 9% of equivalent K ₂ 0, i) 1, 7% of equivalent Β ₂ 0 ₃ , j) 1, 2% of equivalent MgO, and k) 1.68% of other components such as Ti0 ₂ , P ₂ Os, Sn0 ₄ , Bi ₂ 03, or WO3, in a concentration of less than 1% each.

The rest of the procedure remains the same as in case 1.

Example 4.- Procedure for obtaining metallic enamels with gloss and hydrophobes for white-paste ceramic coating.

Obtaining a glossy and hydrophobic metallic enamel on a white-paste stoneware substrate. To perform this process the following formulation is used in percentages by weight with respect to the total weight: a) 10.6% by weight of copper oxide (CuO), b) 2.1% by weight of Fe ₂ O3, d) c) 83.1% by weight of a frit, and e) 4.2% by weight of a clay.

In said formulation, the frit has a composition whose content expressed as a percentage in oxide equivalent to the total is: a) 52.7% of equivalent Si0 ₂ , b) 10.3% of equivalent CuO, c) 9.0% of equivalent CaO, d) 6.1% equivalent At ₂ 0 ₃ , e) 8.8% equivalent Na ₂ 0, f) 3.3% equivalent ZnO, g) 2.2% equivalent Fe ₂ Ü3, h ) 2.7% of equivalent K ₂ 0, i) 3.3% of equivalent B ₂ Ü3, j) 1.2% of equivalent MgO and; k) 1.59% of other components such as Ti0 ₂ , P ₂ Os, Sn0 ₄ , Bi ₂ 03, or WO3, in a concentration of less than 1% each.

The above formulation is homogenized in aqueous medium at a concentration of 60% by weight solids content. To this mixture is added 0.2% by weight of a carboxymethyl cellulose type glue, 0.25% by weight of a tripol sodium phosphate dispersant and 0.05% by weight of an Additive type preservative. The mixture is homogenized by milling in alumina ball mill to constitute a stable suspension. The deposition of this suspension was made by bell on the white paste ceramic support with a variable thickness from 50 μηι to 1000 μηπ.

The enamel deposited on the support was heat treated at a temperature of 1 142 ° C in an oxidizing atmosphere in a fast-cooking monostrate oven. As a result, a vitreous coating of metallic appearance was obtained on the white paste support. This metallic-looking enamel is characterized by high gloss and hydrophobic response.

Claims

1. Composition characterized in that it comprises a copper oxide, at least one fried vitreous, a clay, and at least one metallic oxide that is selected from Fe ₂ O3, Μηθ2, ZnO, CoO, NiO, Cr ₂ 03, Zr0 ₂ , Ce0 ₂ , AI ₂ Ü3, Si0 ₂ or any combination thereof.

2. Composition according to claim 1, further comprising a ceramic pigment.

3. Composition according to claim 2, wherein the percentage by weight of the ceramic pigment is between 1 to 10% with respect to the total weight of the composition.

4. Composition according to any one of claims 1 to 3, wherein the weight percentage of the copper oxide is between 5 to 22% with respect to the total weight of the composition.

5. Composition according to any one of claims 1 to 4, wherein the percentage by weight of the clay is between 3 to 14% with respect to the total weight of the composition.

6. Composition according to any one of claims 1 to 5, wherein the percentage by weight of the metal oxides between 1 and 10% with respect to the total weight of the composition.

7. Composition according to any of claims 1 to 6, wherein the percentage by weight of the fried glass is between 50 and 85% with respect to the total weight of the composition.

8. Composition according to any one of claims 1 to 7, wherein the frit comprises oxides that are selected from Si0 ₂ , AI ₂ Ü3, CaO, PbO, ZnO, Na ₂ O, K ₂ O, MgO, B ₂ O ₃ , BaO, CuO, Fe ₂ O ₃ , P ₂ O ₅ or any combination thereof.

9. Composition according to any of claims 1 to 8, wherein the percentage of Si0 ₂ with respect to the total frit is between 40 and 70% by weight.

10. Composition according to any of claims 1 to 9, wherein the percentage of AI2O3 with respect to the total frit is between 4 and 12% by weight.

eleven . Composition according to any one of claims 1 to 10, wherein the percentage of CaO with respect to the total frit is between 5 and 16% by weight.

12. Composition according to any of claims 1 to 1 1, wherein the percentage of PbO with respect to the total of the frit is less than or equal to 10% by weight.

13. Composition according to any of claims 1 to 12, wherein the percentage of ZnO with respect to the total frit is between 3 and 10% by weight.

14. Composition according to any one of claims 1 to 13, wherein the percentage of Na ₂ 0 with respect to the total frit is between 1 and 10% by weight.

15. Ceramic composition according to any of claims 1 to 14, wherein the percentage of K ₂ 0 with respect to the total of the frit is between 0.5 and 4% by weight.

16. Composition according to any of claims 1 to 15, wherein the percentage of MgO with respect to the total frit is between 0.5 and 3% by weight.

17. Composition according to any of claims 1 to 16, wherein the percentage of B ₂ 0 ₃ with respect to the total frit is between 0.5 and 6% by weight.

18. Composition according to any of claims 1 to 17, wherein the percentage of BaO with respect to the total frit is less than or equal to 5% by weight.

19. Composition according to any one of claims 1 to 18, wherein the size of the copper oxide particles, the metal oxides and the pigment is less than 63 μηπ.

20. Composition according to claim 19, wherein the size of the copper oxide particles, the metal oxides and the pigment is less than 30 μηπ.

twenty-one . Composition according to claim 20, wherein the size of the copper oxide particles, the metal oxides and the pigment is less than 15 μηπ.

22. Composition according to any one of claims 1 to 21, wherein the clay is at least one phyllosilicate or any of its mixtures.

23. Composition according to claim 22, wherein the phyllosilicate is at least one kaolinite.

24. Use of the composition described according to any of claims 1 to 23, as enamel for the ceramic coating.

25. Use according to claim 24, wherein the ceramics are tiles, tiles, bricks, sanitary ware, flooring or decorative elements.

26. Aqueous suspension characterized in that it comprises the composition according to any of claims 1 to 23.

27. Aqueous suspension according to claim 26, wherein the content of the composition is less than 70%.

28. Aqueous suspension according to any of claims 26 or 27, further comprising at least one additive that is selected from thickener, dispersant, preservative or any combination thereof.

29. Use of the aqueous suspension according to any of claims 26 to 28, for the manufacture of enameled materials.

30. Method of obtaining the aqueous suspension described according to any of claims 26 to 28, which comprises homogenization in aqueous medium of the ceramic composition.

31. Method according to claim 30, wherein the homogenization is carried out in a ball mill.

32. Enameled material characterized by comprising the composition described according to any one of claims 1 to 23 and a ceramic support.

33. Enameled material according to claim 32, characterized by having a brightness greater than 63% in direct reflection and greater than 50% in diffuse reflection.

34. Enameled material according to any of claims 32 or 33, characterized in that it comprises a hydrophobicity greater than 90 °.

35. Enameled material according to claim 34, characterized in that it comprises a hydrophobicity greater than 1 10 °.

36. Enameled material according to any of claims 32 to 35, characterized by having a surface roughness of less than 300 nm.

37. Enameled material according to claim 36, characterized by having a surface roughness of less than 100 nm.

38. Method of obtaining the enameled material described according to any of claims 32 to 37, comprising the steps: a) depositing the aqueous suspension described according to any of claims 26 to 28, on a ceramic support, and b) heat treating the product obtained in (a) at a temperature between 900 and 1280 ° C.

39. A method according to claim 38, wherein the ceramic enamel has a thickness between 40 to 1000 μηπ.

40. A method according to any one of claims 38 or 39, wherein the method of deposition of step (a) is selected from a method of hood, veil, disc, spray, immersion, granules, electrostatic deposition, projection thermal, or by using inks for deposition by airbrushing, screen printing or pad printing,

41. Process according to any of claims 38 to 40 wherein the heat treatment of step (b) is in an oxidizing atmosphere.

42. Use of the enameled material described according to any of claims 38 to 41, as a covering or decorative element, in interior or exterior application of floors or walls, in building facades, in urban, furniture, sanitary or ceramic applications technique.