ES2403536A1 - Coloured frits with a lustre effect - Google Patents

Abstract

The invention relates to a coloured frit having an ornamental mineral or iridescent lustre effect, characterised in that its formulation comprises at least one lanthanide selected from the group containing neodymium, cerium, praseodymium and erbium, combined with: at least a second lanthanide different from the first and selected from the same group, or at least one transition element coloured with at least one compound containing an element selected from the group containing chromium, cobalt, nickel, manganese and copper. The invention also relates to a grain, a powder, a slip and a dispersion of ceramic pigments, such as a pigmented ink, which can be obtained from the frit, as well as to the coloured material resulting from any of these products. The invention further relates to the method for obtaining the frit, as well as to the use thereof for the decoration of parts selected from the group containing ceramic, glass and/or metal parts.

Description

COLORED FRIED WITH LIGHT EFFECT

Technical field

The present invention belongs to the field of the qLlmlca Industry, more specifically to the field of luster manufacturing and more specifically to the manufacture of ceramic and glass-ceramic materials decorated with frits that confer an iridescent luster effect on said materials.

State of the art prior to the invention

The luster effect is one of the optical effects that is usually produced, for decorative purposes, on the surface of the glazed coatings of the ceramic tiles, which consists in giving the glazed surface a metallic luster that changes slightly in hue when modifying the angle of incidence of light, by applying a composition that provides these properties.

The luster effect is usually achieved by applying said composition, which is known as fried, on the support to be decorated. Frit means an insoluble glassy material that is formed by melting at high temperatures of a composition consisting of inorganic substances. Within the scope of the present invention, the monocoction process is understood as that which involves applying the enamel on the raw support, with the successive simultaneous firing of the support and the enamel. Likewise, bicoction is understood as the process that consists in preparing the unglazed and cooked support for the first time (sponge cake), generally porous, and the application on it of the enamel, usually in the form of an aqueous suspension powder, after which the glazed cake is baked again. Finally, the third fire process is understood, which consists of applying the decoration to the already glazed tile, after being decorated, by means of screen printing. The third fire receives this name because its application is made on the object already glazed and subjected to two previous cooking: the first, called sponge cake, up to 900 ° C; the second, after the application of the glaze, between 1050-1200 ° C. The third firing is done after decoration, between 750-800 ° C, in appropriate ovens.

Numerous commercial products of this type have been identified in the prior art study, such as the aforementioned frits, inkjet inks, multifunctional metallic lustres, with iridescent effects and with golden finishes among others, their chemical composition being very variable and diverse.

Some metallic lustres are based on noble metals that require third-fire cooking generally limited to temperatures below 1,000 ° C. The procedures for obtaining lustres based on noble metals are remarkably expensive due to the high price of such noble metals and the need for a new third-fire treatment for their application. In addition, metallic-looking lustres do not constitute a vitrified surface and thus their technical properties do not seem entirely adequate as they present ease of wear and low resistance to chemical agents.

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. There are also fried compositions based on a high Cu content without Pb, for materials with metal finishes (Siligardi et al. (2009); Lead Free Cu-Containing Frit for Modern Metallic Glaze; J. Am. Ceram. Soc., 92 [11] 2784-2790). Another method of obtaining metallic enamels for industrial applications based on CuO in lead-free enamels has been published recently (J. Am. Ceram. Soco 92 [11] 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 Na20. 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, Si02, 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.

On the other hand, some authors have analyzed the preparation of silver-based compositions with luster effect in the absence of other noble metals (PTY 1306355 E), and specifically Pb and Cu (JP 55037418 A). However, the costs of these materials are also high.

Another handmade alternative to obtain enamels with a metallic appearance is the use of highly melting enamels based on iron oxides and commonly known as venturine 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. Venturin enamels enhance 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.

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The industrial development of metallic effects in ceramic tiles has been proposed from mixtures of essential oxides such as Si02, A1203, Fe203 and P20S together with certain optional oxides, namely: CaO, MgO, Na20 and K20 (WO 2001/72651). This formulation is characterized by being free of noble metals, by being applied in ceramic tiles and baked in an industrial cooking oven between 11 00-1250 ° C and by having a high content of Fe203 and P20S, in the range 10-30% Y 7-27% by weight respectively. An improvement of the procedures related to the formulations for metallic enamels and high phosphate contents consists in the use of Fe304 as a precursor, since it extends the temperature range for its use by incorporating fluxes such as PbO and presents advantages for the elimination of iron contaminants Thus, application ES 2301364 describes a formulation for obtaining metallic effects that is based on magnetite (Fe304) but combined with an oxide selected from A1203, P205, Si02, PbO and combinations thereof, such that the shades of Metallic are obtained from playing with the proportions of ferrite and PbO / P205.

The limitations of the technique for metallic-looking enamels using compositions with phosphates and iron oxides are multiple, since they can present application problems due to the rheological characteristics of the materials used that result in a 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 Fe203 and P205 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 1,200 ° C, but the high price of phosphate precursors is not resolved.

Other procedures for developing bright metallic-looking tiles try to combine clays with metal oxides when preparing compositions with a luster effect. An example is the composition described in the Spanish patent application ES 2382514 A1, which is used in aqueous solution for the formation of the ceramic coating, also providing a high hydrophobic character. A second example is the modified ceramic formulation of the international patent application W02005061402, which comprises conventional ceramic formulations consisting of a ceramic matrix based on a mixture of oxides in different proportions, which have been modified by adding metal mixtures of metals and alloys of stainless metals of melting points greater than 11 OO ° C and granulometries less than 100 microns. A third procedure has been recently developed (W02008 / 152174), based on the incorporation of metallic nanoparticles dispersed and anchored in nanolibers of sepiolite clay. In this procedure, ceramic glazes with metallic luster are obtained from metallic particles to alloys of micro / nanometric size and / or by particles of different oxides that have a metallic character in the optical range (Fe304, C0304, NbO, TaO, Mn304, MoxOy and WxOy) to precursors that allow obtaining the previous conductive oxides.

Another procedure described in the international patent application WO / ES2002 / 00079 allows to obtain tiles with a metallic outer coating, applied directly on the enamelling of the ceramics, using an electric arc evaporator that allows to obtain a good adhesion of the formed substrate, without using intermediate layers or binders. With this procedure you can obtain tiles that have a metallic outer layer, composed of one of the following elements: Chrome, zirconium, tantalum, titanium or nitride or carbonitride of the mentioned metals, and that depending on the material used in the coating, the tile It has colorations such as gold, metallic gray or violet metal.

It has been found that the addition of aluminum and zirconium oxides to these gloss effect compositions improves the corrosion resistance of the materials on which they are applied (IT 1169927 B).

Tungsten has also been used in gloss effect compositions, such as the composition described in ES 2360781 A1. This document describes a base composition of oxides, characterized in that after its application on a ceramic substrate and subsequent firing it is obtained on the surface of the piece Russellite crystalline formations, which give the ceramic piece an aspect rich in chromatic nuances, iridescent , metallic and luster depending on the quantity and size of crystals present. The relevant structure is Bi2W06 and among the oxides can be mentioned: silicon oxide, boron oxide, lead oxide, sodium oxide, potassium oxide, lithium oxide, zinc oxide, barium oxide, aluminum oxide, oxide of calcium, magnesium oxide, zirconium oxide, cerium oxide, tin oxide, titanium oxide or phosphorus oxide, among others.

Other pigments or decorative materials known in the field are based on Cerium. Thus, there is a frit with luster effect for glazed ceramics described by Siligardi et al. (Ceria-containing Frit for Luster in Modern Ceramic Glaze (2010); J. Am. Ceram. Soc., 93 [9] L ~ 545-2550), based on Cerium and manufactured at high temperature, in which the Ce percentage is considered high (around 8%). Other "pearly" pigments found in the state of the art are based on mica and oxides of Ti or Ce, such as those used in the

Patent CA 1277456 C of MERCK PATENT CMBH in which a maximum temperature heat treatment of 800 ° C is applied, or those described in patent application JP 63176334 A (mica powder with Ti or ferrite dioxide). Other similar frits with gold and silver effect based on mica and titanium are analyzed by Cevalcante et al. (Ceramic application of mica titania pearlescent pigments (2007); Oyes and Pigments 74, 1-8), and used for the manufacture of ceramic tiles by third fire procedure.

In the field of ceramic glazes, some pigments, calcined or not, based on Praseodymium (CN101823902, GB1435234 AY EP090 ~ 5203 A1) have also been described, although the use of this element is important especially in the manufacture of piezoelectric, dielectric: os and electronic elements. Other pigments or chromatic coating agents incorporate praseodymium and metals selected from silver and elements of the rare earth group, although unlike the other materials mentioned they start from an organic base (organic resin of Pt, Pd, Au, Ag ... ).

Known bright metallic enamels are characterized by having a nanostructure on their surface that allows them to have a hydrophobic response with wetting angles for water of 95 ° (Bal. Soco Esp. 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 process are given because it requires the addition of a reducing agent, for example 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 requires specific adjustment of 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.

Other methods for obtaining ceramic surfaces with a metallic gloss appearance have recently been claimed by means of the deposition in the vapolr phase 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, zirconia, 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.

Another recent procedure for obtaining metallic-looking ceramic surfaces consists of incorporating particles smaller than 100 µm of metals or metal alloys with melting points greater than 1100 ° 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.

In short, it should be noted that the metallic-looking frits as a whole have limitations due to:

-

high cost of raw materials, mainly phosphate precursors;

-

The absence of brightness of phosphate-based frits attributed to the presence of crystals

micrometers on the surface that produce diffuse reflection of light, aspect by which

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.

In addition, they have the following limitations:

-

high cost for the use of noble metals applied by the third fire technique;

-

Compositions with phosphates and iron oxides for metallic-looking enamels

they also have application problems due to the rheological characteristics of the

materials used which results in a lack of homogeneity, appearance of defects and

low temperature stability;

-

CuO employment. The main technical limitation is that a frit with an appearance is obtained

non-homogeneous metallized with dark areas that have no luster effect, due to the

formation of inhomogeneous crystallizations

-

use of dispersed and anchored metal nanoparticles in sepiolite nanofibers. The main

Limitation of this technique is that it requires a reducing agent, such as coal dust, to

generate the local and transient reducing atmosphere during the cooking process that preserves the 10

Metal nanoparticles, as well as the formation of surface defects due to crystalline growths of CuO of micrometric size ql.le reduces brightness.

According to the above, it can be affirmed that there are no colored frits in the market with a luster effect, such as gold, for monocooking and bicoction without the need to inevitably carry out a third-fire firing for its application, and without using noble metals that They make these products considerably more expensive, as they have a high price.

The main novelty presented by this invention is the development of colored frits with luster effect, that is, as it can be with golden effects or ornamental stones, by using lanthanides within the neodymium, praseodymium and erbium group or a combination of lanthanides with transition elements colored with at least one compound containing chromium, cobalt, nickel, molybdenum or copper, which allow the development of a frit applicable in monocoction and bicoction processes that give rise to a vitrified surface, with adequate technical characteristics, mainly its resistance to wear and chemical attacks, but that does not require a third fire in its application. It should be noted that none of the documents found combine oxides of transition elements colored with lanthanides or mixture of lanthanides, to achieve bright or iridescent effects. These frits are of special interest in the field of the manufacture of ceramic pieces and materials.

On the other hand, it should be noted that in the sector of the manufacture of decorated ceramic elements, such as tiles, inkjet decorating techniques are widely known, as described for example in Patent ES 2131466 "Automatic procedure of decoration of ceramic substrates ", which describes in a generic way the use of the system of injection of inks in ceramics, although it does not make any reference to the method of preparation of the inks or their formulation. Examples of these inks can be found, for example, in Patent ES 228B916 "Colloidal dispersion of ceramic pigments", which presents in a very general way the manufacture of inks for application by injection by dispersion and grinding, not contemplating any kind of synthesis chemical or element that allows to obtain more intense and lasting colors.

On the other hand, in the patent application ES 2373897 A 1, a method of producing a metal suspension for printing ceramic elements usable for the injection decoration of said ceramic elements characterized by the incorporation of noble metal nano-particles is described. , preferably gold, silver, copper or ruthenium, in the solvents that constitute the base of the suspension, the synthesis of the nano-particles being achieved by reduction reactions in situ, using the solvents that constitute the base of the suspension as a reaction medium , of noble metals with protective groups and an appropriate reducer-stabilizer. Said synthesis process is applicable both directly to the base solvents of the inks, and to suspensions thereof containing ceramic pigment particles. However, this patent does not contemplate the use of transition elements and uses precious metals of high cost.

Although there is an evolution in the quality of the inks used, there are still many problems to be solved, among which we can mention, stability of the suspensions, granulometry of the solid fraction, range of colors and intensity.

One of the main limitations of the inkjet decoration technique, applied to the manufacture of ceramic tiles, is to obtain a good color range. In this sense, numerous developments have been made, as we can find, for example, in the ES Patent 2209634 "New yellow ink for the decoration of ceramic and glass articles by means of Inkjet technology", which describes an ink that uses colloidal titanium to add it to solutions of metal carboxylates, soluble salts, although this ink does not contemplate the use of combination of lanthanides or of these with colored transition elements, object of the present study and does not provide a luster finish, only yellow hue.

There is a great need and interest in the sector of the manufacture of ceramic elements decorated by having a set of inks that allow work in four colors, as is done in other industrial sectors. In order to have this ideal four-color process, one of the main needs to be resolved is to obtain an intense purple ink.

Currently the purple inks used are based on solutions of gold complexes. These types of inks have serious drawbacks due to their printing on uncooked ceramic substrates. In fact, the porous state of the ceramic substrates, together with the ceramic process itself, humidity of the pieces after the enamelling, drying parameters, waiting time before firing the tiles, etc. it can cause defects by migration of the gold complexes, which would cause changes in hue.

Some attempts to use nanometric particles are known, as we find described in patent ES 2298503 "Ceramic dyes in the form of nano-metric suspensions", which uses gold and silver for ceramic products by reaction in a liquid state, and for ceramic use, although It has the disadvantage of

which are not intended for use as injection inks, referring only to ceramic use in general, in addition to not providing for the addition of elements for stabilization, so that durability and homogeneity is expected to be not good. In addition, they have the disadvantage that it uses temperature to obtain the chemical reaction, with the consequent increase in the process and increase the complexity of production and control of results.

The techniques for applying the raw materials used to obtain metallic effects are very expensive. These techniques include the following:

Vapor phase deposition of a coating of a metallic layer of elements such as chromium, zirconia, tantalum, titanium and nitrides. This procedure implies a very high cost since it requires vacuum bells for application in 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. Incorporation of metal particles or metal alloys with a size smaller than 100! -1m. The main limitation of this application technique is the need to perform a subsequent polishing of the ceramic surface after the cooking process to obtain the metallic appearance. In addition, the incorporation of metallic particles presents important problems of rheology, low stability and homogeneity of the slippers of the enamels.

In order to solve the current problem and achieve a luster effect (for example, gold or ornamental stones), the present invention is described, based on the use of fused colored lanthanide and / or transition elements that have the following advantages :

one.

cost reduction. No noble metals are used.

2.

ease in the manufacturing process. The machinery and procedures for its application are commonly used in the ceramic industry for the decoration of parts, no new machinery or any modification in the processes is necessary.

3.

energy and emission savings. Not requiring one or more additional cooking means significant energy savings compared to current productions.

Four.

improvement of technical properties of the final product. If used on the appropriate enamel, its behavior is superior to IPVD and third-fire applications, for example, gilded, in particular scratch resistance, bases or iodine stains.

Description of the invention

Therefore, the main object of this invention is a frit or a range of colored frits with iridescent luster or ornamental mineral effect, characterized in that they comprise in its formulation at least one lanthanide selected from the group consisting of neodymium, cerium, praseodymium and erbium, combined with:

at least one second lanthanide different from the primem selected within the same group, or at least one transition element colored with at least one compound containing an element selected within the group consisting of chromium, cobalt, nickel, manganese and copper.

It has been proven that the frit described provides a luster effect, such as, for example, although not exclusively gold or the color of ornamental stones and minerals, to the products on which it is applied, such as ceramic, glass-ceramic or metallic materials. , having a great potential application in decorative techniques, such as tiles, tiles, cutlery or sanitary ware, among other materials. Thanks to the use of the combinations of lanthanides and lanthanides with colored transition metals such as those described, the iridescence, brightness and tones desired for the material in question are achieved.

The frit defined above has a great value in the field of the art because it is cheaper than known applications, and has a high resistance to stains, lactic, citric, hydrochloric acids, bases, pool salts and cleaning products after forming a vitreous layer on the support decorated with them.

This frit can be used in the manufacture of ceramic, ceramic, or metallic decorated materials by means of monocoction or bicoc processes: with the advantages derived: without the need to inevitably carry out a third-fire firing for its application and without using metals Nobles that make these products considerably more expensive, since they have a high price.

Ultimately, the present invention describes frits that provide gold or ornamental stone effects at a very competitive price because they do not require expensive techniques, such as the traditional third fire technique used to achieve luster from noble metals; and on the other hand, that new raw materials are used with a much lower price compared to the raw materials used in other techniques, such as noble metals.

The compounds in which these lanthanide and transition elements preferably appear are oxides, which are preferably their most stable oxides, although other salts can also be used, for example, halides, such as chlorides or fluorides, since they are also stable.

Preferably, the compound or compounds comprising the lanthanides are comprised in the frit formulation in a percentage comprised between 3% and 20% by weight of the total composition 10 including both limits, being more preferably comprised between 8% and 15% And said percentage being more preferably still 12%.

Also preferably, the compound or compounds comprising the colored transition element are selected from the group consisting of chromium oxide, cobalt oxide, nickel oxide,

15 manganese and copper oxide, the frits being able to comprise any of the combinations of these compounds in percentages comprised between 1% and 10% by weight of the total formulation, including both limits.

The frit may comprise, in addition to the compounds containing the colored transition element and the

20 containing the lanthanides, one or more of the following compounds: carbonates, quartz, dolomite, feldspars, zirconium silicate, nitrates, kaolins, borates and other oxides of elements that are not lanthanides. These compounds are commonly used in the field of art. In this sense, the frit can comprise any other compound that is known to manufacture such products, such as, for example, and not exclusively: boric acid, alumina, titanium dioxide, kaolin, lime oxide, barium carbonate,

25 lime carbonate, potassium carbonate, lithium carbonate, sodium carbonate, quartz, dolomite, alkali and alkaline earth borates, spodumene, potassium feldspar, sodium feldspar, calcium phosphate, zirconium silicate, zinc oxide, alkaline and alkaline earth nitrates, among others.

The iridescent luster effect obtained from the use: ation of the combination of lanthanides or the combination

30 of lanthanides with colored transition metals in the frit can be very varied, but preferably they are golden and aspect effects of ornamental stones and minerals such as indigo copper (covellite). Ornamental stone is understood in the scope of the present invention those stones that after a process of elaboration are suitable to be used as construction materials and decoration elements conserving entirely their physical-chemical characteristics, composition and texture.

In a preferred embodiment, the colored frit with iridescent luster effect has the following formulation, as a percentage by weight of the total composition:

Barium carbonate: 1-2%

40 Calcium carbonate: 2-3% Calcium borate: 9-12% Quartz: 5-7% Dolomite: 5-6.00% Potassium feldspar: 33.00% -37%

45 Sodium Feldspar: 8.00% -9% Zirconium Silicate: 6.0-8% Potassium Nitrate bb: 0.50-2% Cerium Oxide: 5-8% Zinc Oxide: 7-11.00%

50 Praseodymium Oxide: 3-7%

Thanks to this composition, the frit has a bright gold effect. The specified composition preferably has the following content of oxides in its calcined form, in percentage by weight of the total oxides contained in the formulation:

55 Aluminum oxide: 7-9% Boron oxide: 4-5% Barium oxide: 0.5-2% Calcium oxide: 5-7%

60 Cerium oxide: 5-8% Potassium oxide: 4-5% Magnesium oxide: 1-2% Sodium oxide: 1-2% Praseodymium oxide: 3-7%

65 Silicon oxide: 40-43% Zinc oxide: 7-11%

Zirconium Oxide: 3-5%

In another preferred embodiment, the colored frit with iridescent luster effect has the following formulation, as a percentage by weight of the total composition:

Barium carbonate: 1-2% Lime carbonate: 2-3.00% Calcium Borate: 9-12% Quartz: 5-9% Dolomite: 5-6.00% Potassium Feldspar: 34-37% Sodium Feldspar: 9-10% Zirconium Silicate: 6-8% Potassium nitrate bb: 0.50-2% Cerium Oxide: 6-9% Zinc Oxide: 8-11.00% Cobalt Oxide: 1-4%

Thanks to this composition, the frit has an indigo copper effect. The specified composition has the following oxides content in its calcined form in percentage by weight of the total oxides contained in the formulation:

Aluminum Oxide: 7-9% Boron Oxide: 4-5% Barium Oxide: 0.5-2% Calcium Oxide: 5-7% Cerium Oxide: 5-8% Cobalt Oxide: 1-4% Potassium Oxide: 4-5% Magnesium Oxide: 1-2% Sodium Oxide: 1-2% Silicon Oxide: 42-45% Zinc Oxide 8-11% Zirconium Oxide: 4-6%

The described frit is preferably obtained by mixing and melting the components, for example in an industrial oven. In any of its variants, said frit can be presented for transport and commercialization in solid or colloidal dispersion form.

As a preferred form of presentation, the present invention encompasses a granule consisting of the frit described, in any of its variants, having an average particle size between 100 and 700 microns, more preferably between 100 and 500 microns, including both limits . In this case, the frit is not pulverized but is broken or crushed, for example by roller.

In another form of presentation, the frit can be mixed with one or more suspensions such as clays, kaolins, bentonites ... to give rise to a solid composition. More preferably, the solid composition contains a quantity of frit comprised between 90% and 99.5% including both limits in percentage by weight of the total composition. A specific composition is: 93% fried and 7% kaolin. The solid composition can be obtained by mixing the indicated components in a dry way.

In another alternative form of presentation, the frit can be prepared in powder form, mixed with suspensions and molded to an average particle size between 5 and 63 microns, said size being more preferably between 20 and 63 microns and being more preferably still of 20 microns In another preferred embodiment, the frit powder may have a size between 10 and 45 microns (specifically, when used to prepare slip). If it is prepared dry, only the frit is mixed with suspensions and liquidizers and ground. If prepared by a wet route, the frit is mixed with the suspensions and deflocculants in water, grinding everything, then drying and micronizing to the indicated particle size.

From the solid composition or powder described, a slipper can be obtained, which comprises said composition or said powder in aqueous suspension, in a particle size between 5 and 63 microns. Said slip may preferably have a 90: 1 0:35 ratio of frit, suspension (such as kaolins) and water deflocculants. A specific composition of the slip is: 93% fried and 7% kaolin up to 100% mixture, and this in turn mixed with 35% water from the total slip. In a preferred embodiment, the slip can be obtained by mixing the solid composition and water; In this case, the mixture must be wet milled to reach the indicated particle size. In another preferred embodiment,

The slip can be prepared from the fried powder. As in this case said powder already has the appropriate properties, it must simply be mixed with water, "wet", without grinding. If the frit comes from the solid composition, it preferably has an average particle size between 20 and 63 microns, while if it comes from the powder it preferably has an average particle size between 10 and 45 microns.

A dispersion of ceramic pigments to make ink-jet inks can also be obtained from the fried protection object. In the most preferred case, said dispersion is a pigmented ink, which comprises said frit in an amount between 25% and 800to including both limits by weight of the total ink, preferably 30% and 60%, together with one or more selected compounds within the group formed by humectants, defoamers ... and any component known in the field to prepare pigmented inks. The inks are usually prepared by grinding the frit together with the vehicle in which they are suspended and the rest of the components, until reaching a particle size of less than 0.5 microns. In the case of using inkjet heads that work with larger particle inks at some time, such thicker inks can be manufactured by applying the knowledge of the state of the art combined with the present specification. In a preferred embodiment, it is possible to first grind the frit alone, reducing its size, to facilitate and reduce the cost of the milling process of all the components to obtain the dispersion (ink).

A material of ceramic, vitreous, ceramic and / or metallic colored nature with iridescent luster effect is also protected by the frit described above, in any of its variants. This material is preferably selected within a group of products comprising ceramic tiles, tiles, cutlery and sanitary ware, among the most prominent, which in addition to containing the frit may be enameled or not.

Another object of the invention is a method for applying the colored frit with iridescent luster effect to a support of ceramic, vitreous and / or metallic nature, in any of its variants, characterized in that said method comprises the step of applying the frit on the surface of the support.

Preferably, the method is a manufacturing process of the support by cooking. The process includes in this case applying the frit in the form of granules, slips, powders or pigmented ink on the support, raw or not, and then subjecting the whole to a cooking process. The support may or may not have a layer of raw enamel before applying the frit. The cooking temperature can be between 1020 ° C and 1200 ° C and cooking can be done over a time between 30 minutes and 70 minutes, including both limits.

More preferably, said method is of the type selected from monocoction or bicoction of the support. In the case of monocooking, after applying the frit on the surface of a raw support, both are subjected to the cooking process. In this case, the cooking temperature can be between 1090 ° C and 1200 ° C, for a time between 30 minutes and 70 minutes, including both limits.

In the preferred case of bicoction, the method comprises cooking the support only for the first time (the resulting product being known as cake), then applying the frit on the cooked support and re-cooking the whole a second time. In this case, the temperature of the first cooking stage can be between 1100 ° C and 1110 ° C, for a time between 50 minutes and 55 minutes, including both limits, and the temperature of the second cooking stage can be between 1020 ° C and 1090 ° C, for a time between 30 minutes and 40 minutes, including both limits.

In a preferred embodiment, the frit is applied on the surface of the support in the form of a layer or layers with a layer thickness between 20 microns and 1000 microns including both limits, the frit being in the form of granules having an average particle size between 20 microns and 700 microns, including both limits, that is, when it is in the form of granules, slips, or dust. According to the materials described above, when the frit is applied in the form of a granule the layer can have a minimum thickness of 200, and could be up to 1000 microns, since the maximum average particle size can be 700 microns of such so that several granules could accumulate together. When the frit is applied in powder form together with vehicle (silkscreen) or with suspension, deflocculants and water (slip), the thickness of the layer can be between 20 and 400 microns, including both limits.

When the frit is presented in the form of a granule, it can preferably be applied by layer deposition directly on the piece to be decorated, sprinkling it on the surface thereof, or by means of a flat screen.

On the other hand, although the slip is applied by spraying on the surface of the piece to be decorated, it is done in a wet way, since it is in a liquid state. Other forms of application of the slip is the deposition in bell or tilera.

When it is presented in powder form, it can be applied by layer deposition on the support to be decorated by screen printing techniques, together with a screen-printing vehicle, on screen, rotocolor, or exography, techniques widely known in the field of screen printing.

5 When the frit comes in the form of pigmented ink, it is applied by injection.

Finally, the use of the frit described above in any of its forms is contemplated herein, as well as the powder obtainable therefrom, the granule, the slipper or the dispersion of ceramic pigments, especially of pigmented ink, for the decoration of ceramic, vitreous and / or pieces

10 metallic

Brief Description of the Figures

Figure 1: Represents the X-ray diffraction pattern of the sample of ceramic tile with golden luster effect of Example 1.

Tube: Cu

15 Voltage: 40 kV Intensity: 45 mA Monochromator: no Divergence slot: 0.6 mm Receiving slot: 0.6 mm

20 Time constant: 1 s Step size: 0.015 ° From 28 = 20 ° to 28 = 90 °

The diffraction pattern data shown in the figure are collected in the following table:

28(°)

d(Á)

20,84

4,260

21 ,57

4,119

22,61

3,932

25,50

3,492

26,66

3,342

27,00

3,301

27,73

3,216

28,34

3,148

28,66

3,114

28,99

3,079

29,89

2,986

31,43

2,843

31,76

2,814

32,59

2,745

33,54

2,669

33,82

2,647

35,57

2,521

39,41

2,284

42,40

2,129

43,28

2,088

43,93

2,059

46,13

1,965

47,50

1,912

48,25

1,884

48,80

1,864

49,95

1,824

50,74

1,797

51,46

1,774

52,39

1,745

53,32

1,716

57,15

1,610

57,27

1,607

59,30

1,557

Intensidad Table 1

28 (°)

gives)

20.84

4,260

21, 57

4,119

22.61

3,932

25.50

3,492

26.66

3,342

27.00

3,301

27.73

3,216

28.34

3,148

28.66

3,114

28.99

3,079

29.89

2,986

31.43

2,843

31.76

2,814

32.59

2,745

33.54

2,669

33.82

2,647

35.57

2,521

39.41

2,284

42.40

2,129

43.28

2,088

43.93

2,059

46.13

1,965

47.50

1,912

48.25

1,884

48.80

1,864

49.95

1,824

50.74

1,797

51.46

1,774

52.39

1,745

53.32

1,716

57.15

1,610

57.27

1,607

59.30

1,557

Intensity

Possible structure

relative (%) 0.06

Quartz; Zirconium-Orthorhombic Oxide 1.29

Cristobalita; Willemite 0.53

Silicon dioxide 0.52

Silicon dioxide; Willemite 0.73

Quartz 0.65

Zircon 0.84

0.83 Calcium Silicate

Calcium Silicate 2.17

Cerianite; Willemite 10.1

Silicon dioxide; Zirconium oxide and cerium 0.75

Zirconium-Orthorhombic Oxide 2.53

Zirconium Tetragonal Oxide; Calcium silicate; Willemite 0.76

Zirconium-Orthorhombic Oxide 1.95

100.0 Calcium Silicate

Calcium silicate; Zirconium oxide and cerium 9.21

Zircon; Zirconium oxide and cerium; Willemite 0.30

Cristobalita; Zircon 0.33

Quartz; 0.04 calcium silicate

Quartz; Zirconium-Orthorhombic Oxide 0.10

Silicon dioxide; Willemite 0.25

Cristobalita; Zircon; Willemite 0.28

Willemite 0.27

Calcium silicate; Willemite 2.76

Zirconium oxide and cerium 0.39

Willemite 0.38

Silicon dioxide; Zirconium-Orthorhombic Oxide 0.40

Quartz; Zirconium-Orthorhombic Oxide 0.35

Zirconium oxide and cerium 0.10

Zirconium Tetragonal Oxide; Silicon dioxide; Zircon; Willemite 0.04

Zircon; Zirconium-Orthorhombic Oxide; Willemite 1.24

Quartz; Zirconium oxide and cerium 1.50

Quartz; Willemite 0.14

Cerianite; Silicon dioxide; Zirconium Oxide Figure 2: White enamel surface (no luster effect) seen with the backscattered electron signal of the MEB. Magnitude: 1000x

Orthorhombic; Willemite

60.08

1,538 0.31 Quartz; Silicon dioxide; Zirconium and Cerium Oxide

62.26

1,489 0.12 Zirconium Tetragonal Oxide; Zirconium-Orthorhombic Oxide

63.30

1,467 0.09 Silicon dioxide

64.29

1,447 0.07 Willemite

67.96

1,378 0.06 Cryiobalite

70.45

1,335 8.31 Silicon dioxide

72.94

1,295 0.08 Willemite

74.37

1,274 0.06 Willemite

75.80

1,253 0.05 Quartz; Willemite

77.24

1,234 0.09 Zirconium Tetragonal Oxide; Cerianite; Silicon dioxide; Willemite

78.06

1,223 0.37 Zirconium-Orthorhombic Oxide; Zirconium oxide and cerium; Willemite

80.43

1,193 0.21 Cristobalita; Zircon; Willemite

80.69

1,189 0.21 Cristobalita; Zircon; Zirconium oxide and cerium; Willemite

82.70

1,165 0.02 Zirconium Tetragonal Oxide; Zirconium-Orthorhombic Oxide; Willemite

84.28

1,148 0.03 Willemite

86.24

1,126 0.01 Willemite

Figure 3: Global EDX analysis of white enamel (no luster effect)

Figure 4: Surface with golden effect seen with the backscattered electron signal of the MEB. Magnitude: 1000x

Figure 5: Surface with golden effect seen with the backscattered electron signal of the MEB. Magnitude: 10 4000x

Figure 6: Surface with golden effect seen with the backscattered electron signal of the MEB. Magnitude: 10000x

15 Figure 7: Surface with golden effect seen with the backscattered electron signal of the MEB. Magnitude: 20000x

Figure 8: Global EDX analysis of the surface with gold effect

20 Figure 9: EDX analysis of white acicular crystals, identified as B in Figure 8. Presence of Praseodymium and Cerium in different proportions than C

Figure 10: EDX analysis of clusters of small spherical particles, identified as C in Figure 7. Presence of Praseodymium and Cerium in different proportions than B 25 Figure 11: EDX analysis of large, white and bright particles, identified as A in Figure 7

Figure 12: Granulometric distribution of the frit powder: Volume (%) of particles that make up the sample of the frit powder object of the invention as a function of the particle diameter (! -1m). Figure 13: Dilatometry of the gold colored frit frit of Example 1

Figure 14: Spectrophotometry of the luster effect (colorimetry)

35 Examples

Example 1. Preparation of a ceramic product with a golden luster effect by applying the frits described in the present invention in powder form

40 The different raw materials were weighed and mixed, dosed in a fried melting furnace at a temperature of 1400 oC, after a subsequent cooling, a compound formed by the frit was prepared in 94% and suspending until 100% was completed. .

Said compound was ground to a rejection of less than 1% at 44 microns and was used either dry or in a slip-shaped application at densities below 1.60 gr / ml on raw ceramic pieces with engobe and enamel.

Said pieces were cooked in a single layer oven in a single firing, both in porous, stoneware or porcelain cycles, obtaining the surface with the desired appearance.

Example 2. Analysis of the enameled ceramic tile with gold (gold) luster effect in accordance with the present invention described in Example 1.

Crystal Structure Identification

The identification of crystalline phases was analyzed by X-ray diffraction (DRX) of the surface of the piece. The identification of crystalline structures was performed by X-ray diffraction of the surface sample, using a BRUKER Theta-Theta D8 Advance model diffractometer.

The technique consists in making an X-ray beam, of known wavelength, affect a piece. The beam of rays is diffracted and reflected with characteristic angles of the planes of the crystals, obtaining the corresponding diffractogram, from which the mineralogical species present are identified using the sheets supplied by the ICDD for pure crystalline phases.

Scanning Electron Microscopy

From the sample received, a specimen has been cut that contained both an area with white enamel and another area with the gold-colored surface decoration.

Both zones have been observed and photographed with the backscattered electron signal of the field emission scanning electron microscope (FEG Quanta 200F). The backscattered electron signal provides information on topography and composition. It is all the more intense the higher the average atomic number of the sample, so that the lighter areas contain heavier elements (compositional contrast).

The samples were then analyzed with an X-ray energy dispersion microanalysis unit with Si (Li) EDAX Genesis 7000 SUTW (super ultra thin window) detector, connected to the scanning electron microscope (FEG Quanta 200F). This is a semi-quantitative analysis, since the interaction volume of the electron beam with the sample has a depth of the order or greater than 31-lm, and the detector receives the characteristic X-rays of the elements that are in the interaction volume . In addition, it must be considered that with this analysis system the elements of atomic number equal to or greater than 6 (from carbon) are detected.

Specifically, from the study carried out to determine the crystalline phases / crystals that characterize the golden effect on the surface of the support on which the frit is deposited once cooked it appears that they appeared, in addition to minor phases such as cerianite (Ce02), calcium silicate (Ca2 Si04), zirconium oxide (Zr02-Tetragonal), willemite (Zn2Si04), cristobalite (Si02), quartz (Si02), zirconium oxide (Zr02Orthorphic), zircon (ZrSi04) and silicon dioxide (Si02) with crystals of (Ce, Zr) 02. When these crystals were analyzed by scanning electron microscopy, it was noted that there are two types of crystals outside the base enamel, some, very small «1 OOnm) of tetragonal aspect (C particles) that are the most numerous and that agglomerate covering the most of the enamel surface that has an effect and other very bright acicular (B particles), which were presented in smaller numbers (Fig 5).

After the composition of these crystals was analyzed by electron microscopy, it was determined that in the case of particles B there was also a combination of different lanthanides, such as Cerium and praseodymium (Fig. 7) as in the case of particles C ( Fig. 10), the proportion of praseodymium being different in each case.

It is based on these results that the iridescent effect that was achieved by applying the frits object of protection on ceramic, vitreous, vitrocernical and / or metallic supports was due to the appearance and disposition of these on the decorated surface.

Figure 1 shows the diffractogram obtained from the sample, in which the peaks of maximum intensity of the identified crystalline structures have been labeled, as well as other characteristic reflections of lower intensity (the relative intensity of the pure phase is indicated in brackets ). The expanded diffractogram, the test conditions and the table with the complete interpretation of the reflections of the obtained diffractogram are included.

Upon identification of the crystalline structures on the surface of the sample, it was observed that according to the chemical composition of the sample (Figure 8) it was determined that the majority structure was

((Ce, Zr) 02) although the ratio of intensities of this determined phase in the sample did not match the diffraction pattern provided by the ICDD (International Center for Diffraction Data).

It is not ruled out that in the majority structure ((Ce, Zr) 02) some cations may be substituted by Praseodymium.

The crystal structures identified in the sample are indicated below:

Sample 1: Gold effect piece

Majority phase:

-

(Ce, Zr) 02 = Cerium and zirconium oxide ((Ce, Zr) 02) Minority and / or very minority phases: -Ce = Cerianite (Ce02) -CaSi = Calcium silicate (Ca2Si04) -ZrO-Tet = Oxide Zirconium (Zr02-Tetragonal) -Will = Willemite (Zn2Si04) -Cris = Cristobalite (Si02) -Q = Quartz (Si02) -ZrO-Ort = Zirconium oxide (Zr02-0rtorhombic) -ZrSi = Zircon (ZrSi04) -S = Silicon Dioxide (Si02)

From the study carried out by scanning electron microscopy (SEM) it can be concluded that both the indicated particles and A, as well as the small spherical particles identified as C, in Figure 7, presented a composition rich in zirconium and cerium. On the other hand, when comparing the EDX analysis of the white acicular crystals (Figure 9) with the global EDX analysis of the surface with golden effect (Figure 8), an increase in the peak corresponding to praseodymium was observed.

Figure 2 shows the appearance of the surface with white enamel (without frit), seen with the backscattered electron signal of the scanning electron microscope. Its global EDX analysis is presented in Figure 3, where the elements that mostly comprise it have been identified; carbon, oxygen, zinc, sodium, magnesium, potassium, calcium and barium.

When analyzing the surface of the sample in the area with golden effect (Figure 8), the appearance of the peaks corresponding to the zirconium, cerium and praseodymium was highlighted when compared with the composition of the white enamel, also determined by EDX (Figure 3) .

Subsequently, micrographs were made, at different magnifications, of the golden aspect surface (Figure 7, Figure 4, Figure 5 and Figure 6). In Figure 7, large white and bright particles (identified as A), white acicular crystals (identified as B) and clusters of small spherical particles (identified as C) can be distinguished. The composition of these phases, determined by EDX, is shown in Figure 11 and Figure 10, respectively.

Stain resistance

This method consists in the determination of the resistance to stains on the face of the ceramic tiles. The basis of stain resistance was to keep the face in contact with various test solutions for a sufficient time, then subjecting the surfaces to defined cleaning methods, and finally examining them to detect irreversible changes in appearance. The results obtained for chromium, iodine and olive oil are, according to ISO 10545-14, and correspond to the best possible result:

Chrome: type 5 Iodine: type 5 Olive oil: type 5.

Granulometric distributions using Laser Diffraction

The LS Series Coulter particle size analyzer was used to control the particle size distribution of the products obtained, with a diameter between 0.04-2000! -1m. It is a fully automatic multifrequency laser diffraction analyzer.

The particle count by laser dispersion was based on an optical principle according to which small particles that are in the middle of a beam of light disperse it according to a symmetrical and characteristic pattern. The intensity and angle of the scattered light is, within limits, proportional to the volume of the particle as long as it is opaque (refractive index = 1). For this reason, the laser dispersion system is widely used in the analysis of inorganic particles (sediments, sludges, air pollutants, ...). The systems based on dispersion 1¡3ser allow to know the distribution of the particle size of the sample, but not its concentration.

The volume in percentage of the frit particles according to their size is represented in Figure 12, and corresponds to the following values:

Particle diameter (¡.Jm) Volume (%) 10 10 35.8 25 10.1

44 1.12

45 0.98

75 0.0 15 120 0.0

Surface abrasion

The determination of surface abrasion resistance in ceramic tiles was carried out by means of

20 application by rotation of an abrasive load on the surface, and the assessment of wear by visual comparison of the tiles under test with those that are not. It is the most common method in the ceramic industry to determine the resistance to surface abrasion in ceramic tiles. The equipment used was a Gabbrielli W1 9-head abrasimeter.

25 This test is performed mainly on finished parts to give a classification of their abrasion coefficient. The ceramic piece will have a coefficient or another depending on the number of turns it has had to take to abrasive the piece. These coefficients are detailed in the following table:

Table 2

Number of revolutions

Abrasion coefficient

100 revolutions

Hair

150 revolutions

PEII

600 revolutions

PEIII

700-1500 revolutions

PEIIII

2100-6000 revolutions

PEIIV

12000 revolutions

PEIV

The results obtained for the ceramic tile enameled with frit according to the present invention showed a primary abrasion that is classified as PEI 11, that is to say it suffers loss of appearance at 600 revolutions.

35 Chemical attacks

The specimens were subjected to the action of test solutions, and visual assessment of the attack after a defined period of time. The test solutions were:

40 • Weak and strong acids:

o Weak acid: 3% HCI (VIV).

o Strong acid: HCI 18% (VIV).

• Other acids:

o Lactic acid 5% (v / v) 45 o Citric acid (1 OOg / l)

•

Pool salts:

o Sodium hypochlorite solution of 20 mg / L.

•

Weak and strong bases:

or potassium hydroxide (30g / l) 50 or potassium hydroxide (1 OOg / l)

• Household cleaning products:

o Ammonium chloride solution of 100 g / L.

The results obtained are the following:

Table 3

Test

Gold Luster Effect (SFP4619 / 01) ISO standard

Chemical resistance: LACTIC ACID 5% (v / v)

GHA EN ISO 10545-13

Chemical resistance: CITRIC ACID (100g / l)

GLA EN ISO 10545-13

Household cleaning products: AMMONIC CHLORIDE (100g / l)

GA EN ISO 10545-13

Chemical resistance: 18% CHLORIDIC ACID (v / v) 3% CHLORIDIC ACID (v / v)

GHA GLA EN ISO 10545-13

Chemical resistance: POTASSIC HYDROXIDE (30g / l) POTASSIC HYDROXIDE (100g / l)

GLA GHA EN ISO 10545-13

Pool salts: SODIUM HYPOCLORITE (20mg / l)

GA EN ISO 10545-13

Brillometry

The determination of the brightness units (UB) on the flat surfaces of the pieces was performed with an Elcometer 406L statistical glossometer. The meter can perform the statistical analysis of the brightness readings

10 stored in its memory. The Elcometer 406L contained an LED light source, a light detector and an incident system. The light detector was set at an angle of incidence of 60 ° and measured the light reflected by the sample in a small area.

The brightness analysis for the case studied yielded a value of 193.5 UB., Being the value for a conventional crystalline lens of 95 UB.

Surface scratch hardness according to Mohs

A test for determining the surface scratch hardness according to Mohs was performed on a finished piece 20 coupled to a matte enamel, the result being 5 according to ISO UNE 67-101-92.

Dilatometries

The equipment used in this work was a DIL 801 L dilatometer and had a quartz tube where a length sensor, the test tube and a thermocouple were placed. The test tube had specific dimensions determined by the design of the equipment. The result is shown in Figure 13.

Colorimetries

30 The system used for color measurement in the laboratory was the CIE (Comossion Intermationale de / 'Ec / airage) system, using a solid colorimeter. The CIE System is based on the physical patterns of wavelength, excitation purity and light intensity, which represent specific and universal variables.

Also called ICI System, it is based on measurement data with which colors can be achieved

35 mixing the appropriate proportions of the three additive primary colors: red, green and blue. Taking into account this fact, the CIE system translates a color to the parameters X, Y, Z. Within this CIE system, a transformation called Hunter Lab system is used, which also takes into account these coordinates, reduced to two: (a, b), the clarity L indicating a percentage of color saturation.

40 The results obtained for the gold-colored colored frit are shown in Figure 14.

Example 3. Analysis of an enameled ceramic tile with indigo copper luster effect in accordance with the present invention

45 Table 4

essays

Indigo Copper ISO standard

Stain Resistance Determination

Chrome: type 5 Iodine: type 5 A. Olive: type 5 EN ISO 10545-14

Chemical resistance: LACTIC ACID 5% (v / v) Chemical resistance: CITRIC ACID (100g / l) Household cleaning products: AMMONIC CHLORIDE (100g / l) Chemical resistance: CHLORID HYDIC ACID 3% (v / v) (v / v)

GHA GLA GA GHA GLA EN ISO 10545-13 EN ISO 10545-13 EN ISO 10545-13 EN ISO 10545-13

Pool salts: SODIUM HYPOCLORITE (20mg / l)

GA EN ISO 10545-13

Determination of surface scratch hardness according to Mohs

5 UNE 67-101-92

Claims (30)

1. A colored frit with an iridescent luster or ornamental mineral effect, characterized in that it comprises its formulation at least one lanthanide selected from the group consisting of neodymium, cerium, praseodymium and 5 erbium, combined with: at least one second lanthanide different from the first selected within the same group, or at least one transition element colored with at least one compound containing an element selected within the group consisting of chromium, cobalt, nickel, manganese and copper.

2.

The frit according to the preceding claim, wherein the compounds containing the lanthanides and the colored transition elements are selected from oxides and halides.

3.

The frit according to any one of the preceding claims, wherein ellanthanide is contained in at least

15 an oxide that is comprised in the formulation of the frit in a percentage comprised between 3% and 20% by weight of the total composition including both limits.

Four.

The frit according to any one of the preceding claims, wherein the colored transition element is contained in at least one oxide selected from the group consisting of chromium oxide, cobalt oxide, nickel oxide, manganese oxide, copper oxide and any combination thereof.

5.

The frit according to the preceding claim, wherein the colored transition element is contained in at least one compound that is comprised in the formulation of the frit in a percentage comprised between 1% and 10% by weight of the total composition including both limits.

6.

The frit according to any one of the preceding claims, comprising at least one component selected from the group consisting of: carbonalios, quartz, dolomite, feldspars, zirconium flour, nitrates, kaolins, borates and other oxides of elements other than lanthanides.

7.

The frit according to any one of the preceding claims, which has an iridescent effect selected from the group consisting of gold, silver or ornamental stone or mineral effect.

8.

The frit according to any one of the preceding claims, which has the following formulation in

percentage by weight of the total frit and has an iridescent effect of gold color: 35 Barium carbonate: 1-2% Lime carbonate: 2-3% Calcium Borate: 9-12% Quartz: 5-7% Dolomite: 5-6.00% Potassium Feldspar: 33.00% -37% Sodium Feldspar: 8.00% -9% Zirconium Silicate: 6.0-8% Potassium nitrate bb: 0.50-2 45 Cerium oxide: 5-8% Zinc oxide: 7-11, 00% Praseodymium oxide: 3-7% 9. The frit according to the preceding claim, which has the following content of oxides in its calcined form, in percentage by weight of the total oxides contained in the formulation: Aluminum Oxide: 7-9% Boron Oxide: 4-5% Barium Oxide: 0.5-2% 55 Calcium oxide: 5-7% Cerium oxide: 5-8% Potassium oxide: 4-5% Magnesium oxide: 1-2% Sodium oxide: 1-2% Praseodymium oxide: 3-7% Oxide Silicon: 40-43% Zinc Oxide: 7-11% Zirconium Oxide: 3-5% The frit according to any one of claims 1 to 7, which has the following formulation in percentage by weight of the total frit and has a metallic effect of indigo copper: Barium carbonate: 1-2% Lime carbonate: 2-3.00% Calcium Borate: 9-12% Quartz: 5-9% Dolomite: 5-6.00% Potassium Feldspar: 34-37% Sodium Feldspar: 9-10% Zirconium Silicate: 6-8% Potassium nitrate bb: 0.50-2% Cerium Oxide: 6-9% Zinc Oxide: 8-11.00% Cobalt Oxide: 1-4% 11. The frit according to the preceding claim, which has the following content of oxides in its calcined form, in percentage by weight of the total oxides contained in the formulation: Aluminum Oxide: 7-9% Boron Oxide: 4-5% Barium Oxide: 0.5-2% Calcium Oxide: 5-7% Cerium Oxide: 5-8% Cobalt Oxide: 1-4% Potassium Oxide: 4-5% Magnesium Oxide: 1-2% Sodium Oxide: 1-2% Silicon Oxide: 42-45% Zinc Oxide: 8-11% Zirconium Oxide: 4-6%

12.

A granite consisting of the frit described in any one of claims 1 to 11, characterized in that it has an average particle size between 100 and 700 microns, including both limits.

13.

A solid composition obtainable from the frit described in any one of claims 1 to 11, characterized in that said frit is mixed with at least one suspension selected from the group consisting of clay, kaolin, bentonite and any combination thereof.

14.

Solid composition according to the preceding claim, which has an amount of frit comprised between 90% and 99.5% including both limits in percentage by weight of the total composition.

fifteen.

A powder obtainable from the frit described according to any one of claims 1 to 11, characterized in that said frit comprises at least one suspension and has an average particle size between 5 microns and 63 microns including both limits.

16.

Powder according to the preceding claim, further comprising at least one fluidizer when obtained dry or at least one deflocculant when obtained wet.

17.

A slip obtainable from the solid composition described in any one of claims 13 or 14 or from the frit powder described in any one of claims 15 or 16, containing said composition or said water powder.

18.

Slip according to the preceding claim, which has a ratio of solid composition or water powder of 65:35.

19.

Slip according to any one of claims 17 or 18, which has an average particle size between 5 and 63 microns.

twenty.

A dispersion of ceramic pigments obtainable from the frit described in any one of claims 1 to 11, which contains said frit in an amount between 25% and 80% including both limits by weight of the total ink, and has a size particle medium less than 0.5 microns.

twenty-one.

The pigment dispersion according to the preceding claim, which is a pigmented ink.

22

A material of a ceramic, vitreous, vit: roceramic and / or colored metallic nature with iridescent luster effect by means of the granule described in claim 12, the frit powder according to any one of the

claims 15 or 16, the slip described in any one of claims 17 to 19 or the dispersion of any one of claims 20 or 21. 23. The material according to the preceding claim, which is selected from the group consisting of ceramic tiles, tiles, cutlery and sanitary ware. 24. A method for applying the colored frit with iridescent metallic luster effect in the form of a granule as described in claim 12, of powder according to any one of claims 15 or 16, of slipper according to any one of the claims 17 to 19 or dispersion according to any one of the Claims 20 or 21 to a support of a ceramic, vitreous, ceramic and / or metallic nature, said method being characterized in that it comprises the step of applying the frit on the surface of the support. 25. The method according to claim 24, which comprises applying the frit on the support and subsequently subject the whole to a cooking process at a temperature between 1 0200e and 12000e for a time between 30 minutes and 70 minutes, including both limits. 26. The method according to any one of claims 24 or 25, which is selected from a monocooking process or a bicoction process of the support. The method according to the preceding claim, where in the case of monocooking: the frit is applied on the surface of a raw support and both are subjected to a cooking process at a temperature between 10900e and 12000e for a time comprised between 30 minutes and 70 minutes, including both limits. The method according to claim 26, wherein in the case of bicoction: the support is first baked, to subsequently apply the frit on the cooked support, and subject the fried-support assembly to a second cooking; the temperature of the first cooking stage between 11000e and 11100e and its duration 30 between 50 minutes and 55 minutes including both limits, and the temperature of the second cooking stage between 10200e and 1 0900e and its duration between 30 minutes and 40 minutes, including both limits. 29. The method according to any one of claims 24 to 28, wherein the frit is applied on the surface of the support in the form of a layer or layers with a layer thickness between 20 microns and 1000 microns 35 including both limits, the frit having an average particle size between 20 microns and 700 microns, including both limits, when said frit is in the form of a granule, powder or slip. 30. The method according to any one of claims 24 to 29, wherein the frit is applied by sprinkled dry on the surface of the support or by flat screen when it is in the form of granules. 31. The method according to any one of claims 24 to 29, wherein the frit is applied by wet spraying, bell deposition or fillet deposition when it is presented as a slip. 32. The method according to any one of claims 24 to 29, wherein the frit is applied by screen printing when it is presented in the form of a solid composition, together with a screen printing vehicle, by means of a screen, rotocolor or flexography. The method according to any one of claims 24 to 28, wherein the frit is applied by injection when it is presented as a dispersion of ceramic pigments. 34. Use of the granule described in claim 12, of the powder of claims 15 or 16, of the slip described in claims 17 to 19 or of the dispersion of claims 20 or 21 for 55 decoration of selected pieces within the group consisting of ceramic, vitreous, ceramic and / or metallic pieces.