WO2002026650A1

WO2002026650A1 - Ceramic building material for covering facades, floors and walls and method the production thereof

Info

Publication number: WO2002026650A1
Application number: PCT/ES2001/000329
Authority: WO
Inventors: Francisco Sanmiguel Roche; Carlos Concepcion Heydorn; Vicente Ferrando Catala; Juan Vicente Corts Ripoll
Original assignee: Torrecid S.A.
Priority date: 2000-09-28
Filing date: 2001-08-23
Publication date: 2002-04-04
Also published as: AU2001285954A1; CN1392869A; JP2004509830A; ES2169686A1; BR0107287A; ES2169686B1

Abstract

The material basically consists of multi-layered slabs resulting from adequate thermal treatment of an assembly formed by various frit layers, a decorated sheet being placed between said layers. The particle size of the frits and heating and cooling time of the assembly should be regulated in such a way that the final slab comes out with a decorated design that is visible through the glazing formed as a result of cooling of the frits that were molten during thermal treatment. Said ceramic material is used for covering facades, floors, walls or any other smooth surface as a method for decorating with final appearance resembling granite, marble, natural stone amongst other

Description

TITLE

"Ceramic construction material for cladding facades, floors and walls and its manufacturing method".

BACKGROUND

The present invention patent refers to a construction material, made from frit, in the form of rectangular slabs for cladding facades, floors and walls, as well as its manufacturing and decoration method to obtain final aspects similar to granites, marbles or natural stones.

There are numerous patents in which different methods of manufacturing ceramic or glass-ceramic building materials for coating facades, floors and walls from frit are described. The most significant patents in this regard are those mentioned below:

US5066524 Crystallized glass article with cnlored small masses dispersed in a surface thereof

US5275978 Colored crystallized glass article and method for producing the same.

The manufacturing method described in these patents is fundamentally based on the deposition of frit in the form of grains of controlled size on plates or supports of refractory material. These grains are in contact with each other leaving air between them, which in turn is in contact with the surface through open channels. Subsequently the refractory + fried set is subjected to a heat treatment

until reaching a maximum (normally above 1000 ° C), maintenance at that maximum temperature and controlled decrease in temperature until reaching room temperature. Said heat treatment will depend on the composition of the frit used and the type of final material that is intended to be obtained. The amount of frit deposited on the refractory plate must be such that after the heat treatment a slab of the intended format is obtained (width x length x height) that can be used as a construction material for the lining of walls, floors, facades or any Another type of flat surface. On the refractory plate, before placing the frit, it is convenient to apply a light layer of powder refractory material (for example alumina) to prevent the frit, which softens during the heat treatment, is adhered to the plate or refractory support The composition of the frit used can be of a very different nature depending on the type of final material that is intended to be obtained.

With all this, a ceramic construction material valid for the lining of walls, floors, facades or any other flat surface is obtained. Can be used chips generated slabs completely transparent, in which case the heat treatment necessary is simply to increase the temperature at a controlled rate, such that during said increase frit particle van ^s' mterizando each other eliminating the air that was between them and later begin to soften merging each other. The temperature continues to rise until a maximum temperature is reached at which the frit particles have lost their identity and are completely fused, generating a slab of molten material free of bubbles. The maximum temperature is maintained for the time necessary to achieve that the slab of molten material free of bubbles is vitreous and completely homogeneous, so that all the frit particles have melted in their entirety and there are no remains that may cause problems in cooling. After this time the temperature begins to decrease in a controlled way to avoid tensions that can lead to ruptures of the slab obtained until reaching room temperature. The temperature profile followed will depend on the composition and size of the frit grains used. The slab at room temperature has a transparency similar to that of the glass used in windows and has the appropriate characteristics to be used as a building material in the cladding of both external and internal walls. Additionally, the slab at room temperature can be subjected to a polishing process to give it an appearance similar to that of float glass. You can also use frits that generate completely opaque or translucent slabs. For this the frits in question must have a composition such that during the heat treatment there are devitrifications of crystals of high refractive index. Depending on the type, size and number of crystals the slabs will be completely opaque or translucent.

To achieve this type of slabs, in addition to using frits with the characteristics described in the previous paragraph, it is also necessary to use a specific heat treatment that favors the formation of crystals. Said heat treatment basically consists of a controlled increase in temperature until reaching the nucleation temperature (temperature at which nuclei of crystals of infinitesimal size appear). The material is maintained at the nucleation temperature for the time necessary to generate the maximum number of crystallizing nuclei. The temperature is increased again in a controlled manner until it reaches the crystallization temperature (temperature at which the crystals begin to grow in size). The material is maintained at the crystallization temperature for the time necessary for the crystals to reach the required size. The temperature is increased again in a controlled manner until the maximum treatment temperature is reached. As in the case of transparent slabs as the temperature rises, the frit grains begin to sinter, joining each other and eliminating the air they enclose between them, and softening to form a slab of molten material free of bubbles, if well, in the case of opaque or translucent slabs the molten material will be formed by a vitreous part and by a crystalline part generated in the nucleation and crystallization stages. Once the necessary time has elapsed at the maximum temperature, the temperature is reduced in a controlled manner to avoid tensions that can lead to ruptures of the slab obtained until reaching room temperature. The temperature profile followed will depend on the composition and size of the frit grains used, as well as the opacity or translucency required. The slabs thus obtained have the appropriate characteristics to be used as a building material in the cladding of both external and internal walls. In addition, due to the existence of crystals embedded in the vitreous phase, these slabs have an abrasion resistance significantly higher than that of transparent slabs, so they are also suitable for floor covering. Said abrasion resistance will depend on the number of devitrified crystals, the type of crystal and its size. Additionally, the slab at room temperature can be subjected to a polishing process to give it an appearance similar to that of polished natural stones. The materials described above are susceptible to decoration by different methods, thereby reaching final products that have greater aesthetic performance.

• Decoration by mixing different color grains: frit grains of different colors can be used, which randomly mixed in the appropriate proportions will provide final products with stained surfaces of different shades. In addition, these colored frits may or may not have a tendency to devitrification, thus differentiating the spots by their transparency or opacity. With all this you get final products that have a certain appearance similar to some granites. • Decoration by mixing different colored grains of frit: the frit grains of different colors indicated in the previous point can be placed on the plate to refract it in certain positions, for example, to alternate stripes of colored and uncoloured frit, obtaining with it final products with geometric drawings. • Decoration by spraying colored liquids: once the frit grains are deposited on the refractory plate, spraying can be carried out, by airbrush or any other technique that allows it, of colored liquids on the frit grains. Spraying can cover the entire area occupied by frit grains or it can be applied selectively in areas by using masks or screens. As colored liquids, soluble colors or salts (complexes or salts of chromophores cations dissolved in water) or suspensions of colored ceramic enamels with ceramic pigments can be used. All these liquids, regardless of their nature, must be compatible with the frit grains used as the basis for obtaining the slab in question, so that they do not generate defects in the final product. The materials thus obtained can range from single color slabs to have a certain appearance similar to marble.

More decoration methods could be described, but all the known ones have in common that the final product obtained presents a huge lack in the definition of the drawing, being also very limited the aesthetic effects that can be achieved. All this leads to this type of materials having a difficult acceptance in the market, despite the good mechanical and abrasion properties they present.

Description of the invention

As already mentioned, everything exposed so far is described in different articles and patents, where the composition of the frits, treatment cycles, etc. are indicated. However, as has also been shown above, the ceramic building materials described in the state of the art have a number of limitations that make them difficult to commercialize. These limitations mainly focus on the impossibility of obtaining products with an adequate aesthetic appearance, both because of the low definition of the drawings achieved with the decoration methods described, and because of the low range of aesthetic effects that can be achieved. The object of this invention gives solution to the aforementioned problem, since it allows to obtain ceramic building materials in the form of rectangular slabs with an appearance similar to any type of granite, marble or natural stone, without limitations of colors, designs, etc. It basically consists of a slab composed of several layers of fried grains between which enamel sheets or other material decorated with the desired design have been placed as a sandwich. Once subjected to heat treatment, the set of layers of frit grains + decorated sheets, the ceramic construction material with the desired aesthetic appearance is obtained, since the selected frits have the appropriate composition to generate a glaze that allows the colors to be appreciated through them and the design provided by the decorated sheets. This product can be subjected to cutting and grinding the edges, surface polishing or other treatments to achieve different final finishes. The frits used in the different layers must have a composition that allows a perfect coupling between them, so that they do not generate immiscibilities during the heat treatment that can alter the aesthetic effect sought. They must also have compatible expansion coefficients so that no stresses arise in the final product that can lead to cracks. Equally important is the surface tension and melt viscosity of the frits, since if these parameters are not optimized, surface defects, such as depressions or others, would appear that would cause a rejection of the final product. In the same sense, the sheets incorporated between the different layers of frit also have to meet the requirements of compositional compatibility, dilatometric, surface tension and viscosity in molten, with the frits with which they are in contact, to avoid the problems that are They just mentioned. Another of the fundamental parameters that must be optimized is the granulometry of the frit grains used, since it depends that after the heat treatment, glazes free of occluded air and completely covered surfaces are obtained. These last two characteristics are of great importance when it comes to obtaining a high quality final product. A granulometry of the too fine frit grains would lead to said frit grains melting earlier than desired, trapping air between the junction areas of some grains with others. Subsequently, if the final product is subjected to a polishing process, the occluded air bubbles surface, which is detrimental to the mechanical and aesthetic properties of the material. On the contrary, if the granulometry of the frit grains is too coarse, said frit grains do not fully melt during the heat treatment, providing glazes that partially cover the surface and therefore the final product obtained does not meet the basic requirements. for marketing Also of great importance is the cycle (time and temperature profile) of the heat treatment applied, which will depend both on the nature of the frits used and the granulometry thereof. This parameter takes on greater relevance in the case that you want to generate crystals in the glazes, as already described above. In short, to obtain a final product with the desired characteristics, it is necessary to optimize together the composition of the sheets, the composition and granulometry of the frits and the heat treatment cycle.

For a better understanding of the object of the present invention, the manufacturing process of this new construction material is described below. To do this, first of all it is described to obtain multilayer slabs without decorating, subsequently obtaining the decorated sheets and finally joining both elements to obtain decorated multilayer slabs. 1.- Multilayer slabs

In the description of the state of the art it has been described to obtain slabs formed by a single layer of the same material, either a completely transparent material (composed only of vitreous phase) or an opaque or translucent material (composed of vitreous phase and crystals ). However, with a manufacturing method similar to that described, multilayer slabs can be obtained. For this, on a refractory plate similar to that used in monolayer slabs, coated with a refractory powder (alumina), a first layer of frit grains of controlled size is deposited. Once this first layer is formed, a second layer of grains of controlled size of another frit other than the first is deposited. In this way, successive layers could be accumulated until the material with the desired characteristics was reached. The set of refractory plate + layers of frit grains is subjected to a thermal treatment that will depend on the frits used and the characteristics and properties of the final product that you want to obtain, but in general lines they will follow the basic premises set forth in the previous sections . With the described methodology, materials of a very diverse nature can be obtained depending on the intended use of them or the surface and aesthetic finish that is sought. As an example, in bilayer materials the following combinations can be mentioned among others:

• Opaque bottom layer + Transparent top layer. ^• • Opaque lower layer + Translucent upper layer.

• Translucent lower layer + Transparent upper layer. It is an indispensable condition that, so that the multilayer slab obtained does not present defects, the fried grains that are combined are compatible in a whole series of characteristics (granulometry, melt viscosity, surface tension, expansion coefficient, miscibility, etc.) 2.- Decorated sheets

To obtain this material, it is based on a slip of the enamel that is to be formed in the form of a sheet, prepared as described in the patent application previously filed by the applicant on the same date, which, by any of the known and existing methods in the market (tape, curtain, etc.) it is deposited on a support, usually of a plastic nature, although glass, metal, etc. can also be used, forming a thin layer. Once said enamel layer is dried, it is separated from the support, obtaining the corresponding sheet, which is decorated with the desired design by means of any of the methods known and existing in the market (screen printing, roller, decal, etc.).

By any of the methods described, sheets of a specific format or continuous sheets of a certain width can be manufactured that can be wound around an axis. These continuous sheets can subsequently be cut to the required sizes.

The lamination methods set forth above have been mentioned by way of example only, since in the state of the art different methods can be found that are also perfectly valid for obtaining decorated enamel sheets.

Another possibility to obtain a decorated sheet is to decorate by any of the methods known and existing in the market (screen printing, roller, decal, etc.) a roll of plastic or any other material that serves as a support of the design that is want to contribute Both the nature of these materials and the composition of plastics can be multiple and very different, without this suppose any type of restriction for the field of application covered by the present invention.

The material that is applied in the process of decoration of the sheet (ink), as well as the different methods used for its preparation are perfectly known, any of which are used to prepare inks to decorate tiles, dishes, porcelain, may be valid. sanitary, refractory, etc.

Obtaining a decorated sheet is not restricted to the methods and materials described above, but only those most significant have been cited by way of example to clarify the concept of what is meant by the term "decorated sheet". 3 decorated multilayer slabs

The manufacturing process of a bilayer slab decorated with a decorated sheet that provides the desired design is described below. On a plate of refractory material covered with refractory powder (for example alumina) a certain amount of frit grains is deposited so that the entire refractory plate is perfectly covered, thereby constituting a first bed of frit grains. The decorated sheet prepared as described above is placed on this first bed, which provides the desired design. Finally, a certain quantity of fried grains is deposited on the decorated sheet so that the entire decorated sheet is perfectly covered, constituting the second bed of fried grains. The refractory plate set + first bed of frit grains + decorated sheet + second bed of frit grains is subjected to a heat treatment that will depend on the frits and the decorated sheet used and the characteristics and properties of the final product that is want to obtain, but in general terms they will follow the basic premises set forth in the previous sections. Following a procedure similar to that described for bilayer slabs, multilayer slabs can be obtained, simply alternating layers of frit grains and decorated sheets, which allows obtaining very different final finishes.

In all cases, both the frit grains and the decorated sheets used must comply with a series of characteristics so that the final product does not have defects that make its commercialization unfeasible. These characteristics are summarized mainly in an adequate grain size, melt viscosity, surface tension, expansion coefficient, miscibility, etc. so that the different layers of frit grains and the decorated sheets have a good compatibility between them. In the examples cited below, the appropriate values of each of the aforementioned characteristics are set forth in detail, without implying any type of restriction to the field covered by the present invention. TABLE I

* Data obtained by heating microscopy

EXAMPLE 1: manufacture of an uncoated bilayer slab (opaque bottom layer /

translucent top layer)

On a refractory plate (Remcor 1S of the company Acmé Maris) of 450 x 450 mm format a layer of 25 grams of alumina (calcined alumina HTM 30 from Duprint) is deposited by spraying a suspension at 50% by weight of powder of Arúmiña eñ gúa ^~ dé man ^~ érá ^" q ^" ue ^_ Ta ^" píacá de refractory is completely covered. Once formed, the alumina bed is deposited on it so that 2950 g of grains of the frit 1 are homogeneously covered (see Table I) with a granulometry between 5000-800 μm On this bed of grains of frit 1 1150 g of frit 2 is then deposited (see Table I) with a granulometry 2000-800 μm. The whole (refractory plate + alumina bed + fried bed 1 + fried bed 2) is subjected to the following heat treatment in an electric oven:

Stage 1: heating at 15 ° C / min to 875 ° C.

Stage 2: maintenance 45 'at 875 ° C (sintering)

Stage 3: heating at 4 ° C / min up to 950 ° C

Stage 4: maintenance 10 'at 950 ° C (crystallization)

Stage 5: heating at 7.5 ° C / min up to 1100 ° C

Stage 6: maintenance 60 'at 1100 ° C (maturation)

Stage 7: cooling at 15 ° C / min to room temperature. In stage 2 (sintering) the grains of frits 1 and 2 gradually melt, eliminating the air between them. In stage 4 (crystallization) the nuclei of the crystals of frits 1 and 2 are generated. In stage 6 (maturation) the nuclei of the crystals generated in stage 4 are proceeded to grow. The crystals generated in frits 1 and 2 are white crystals of wollastonite, but given the difference in chemical composition of frits, frit 1 has a greater tendency to crystallization than frit 2, so that in the first one a greater number of nuclei have been generated of crystals in stage 4 and these have grown to a greater extent in stage 6. Due to this difference in number and size of the crystals the lower layer is white and completely opaque, while the upper layer is whitish and translucent, so which allows to see the white and opaque lower layer. If the slab obtained is observed transversely, there are two distinct layers corresponding to frits 1 and 2 and a small interface layer between them. The final thickness of the frit layer 1 after heat treatment is 13-14 mm, while that of the frit layer 2 is 4-5 mm.

Once the slab has cooled, it is polished by the use of successive abrasive cloths in which its fineness is increased until a specular finish of the slab is reached. Given the optimum heat treatment used, in the slab obtained there has been virtually no occluded porosity, so when polishing it, only a few isolated pores can be observed on the surface (no pores per piece <10) that at no time are detrimental of the aesthetic appearance of the final product. It can be seen in the polished slab how the frit grains have joined each other appearing differences in hue and appearance between the center of said frit grains and the joining areas between each other, which gives the final product an appearance of single color granite. EXAMPLE 2: manufacture of an uncoated bilayer slab (opaque bottom layer / transparent top layer)

It is operated in the same way as in Example 1 but replacing the frit 2 that is deposited in the top layer with the frit 3. This frit does not generate crystals during the cooking process, so that the top layer obtained is completely transparent and allows to clearly and clearly appreciate the lower opaque white layer. Since it is not necessary to generate crystals in the upper layer, the cooking cycle used changes with respect to that set forth in example 1, becoming the following: Stage 1: heating at 15 ° C / min to 870 ° C. • Stage 2: maintenance 30 'at 870 ° C (sintering) Stage 3: heating at 4 ° C / min up to 910 ° C Stage 4: heating at 10 ° C / min up to 1065 ° C Stage 5: maintenance 10' at 1065 ° C Stage 6: cooling at 15 ° C / min to room temperature EXAMPLE 3: manufacture of a decorated plastic sheet.

A solution is prepared with the composition 1 indicated in Table II. A homogeneous layer of said solution is deposited by means of the tape cocking technique on a Mylar-type plastic support. Once the solvents have evaporated (water and ethanol), a 500 x 500 mm and 300 μm thick sheet is obtained, which is separated from the plastic support. The size of the sheet can be any that allows the technical means available and will also depend on the size of the final product to be obtained. On the sheet obtained, screen printing pastes of the compositions 2, 3 and 4 indicated in Table II are applied by screen printing. The preparation of screen printing pastes is carried out by any of the methods commonly used in the ceramic floor and wall tiles sector. Each of the silkscreen pastes provides a different color and drawing, so that the overlay of them on the sheet gives us a decorated sheet that already has the appearance of marble or design that is intended to be obtained. The decorated sheet thus obtained is perfectly manageable and transportable, and can be easily applied on beds of frit grains, as described in later examples. It is important to highlight that both the components of the sheet and those of the screen printing pastes have been designed and optimized so that they do not cause defects when. said decorated sheet is used in the manufacture of decorated multilayer slabs, as also described in later examples. TABLE II

EXAMPLE 4: manufacture of a bilayer slab decorated with a sheet of the type described in example 3 (opaque lower layer / translucent upper layer) On a refractory plate of 900 x 350 mm format a layer of 35 grams of alumina is deposited by spraying a 50% by weight suspension of alumina powder in water so that the refractory plate is completely covered. Once the alumina bed is formed, it is deposited on it so that 5000 g of grains of the frit 1 are homogeneously covered (see Table I) with a particle size between 5000-800 μm. The form of deposition of the frit should be such that once applied it provides a surface as smooth as possible. For this, it is convenient to use automatic loading methods (similar to the loading carts of the presses used in the ceramic floor and wall tiles sector) or to make a leveling or leveling with some type of tool. A decorated sheet prepared as described in example 3 but of 900 x 350 mm format is then deposited on this bed of grains of the frit 1. Once the sheet is applied, 800 g of the frit 2 is deposited thereon (see Table I) with a 2000-800 μm particle size. The assembly (refractory plate + alumina bed + frit bed 1 + decorated sheet + frit bed 2) is subjected to the same heat treatment set out in Example 1. EXAMPLE 5: manufacture of a bilayer slab decorated with an enamel sheet decorated (opaque bottom layer / transparent top layer)

The process is similar to that described in example 4 but as an enamel sheet decorated with the 900x350 mm format and the frit deposited on the sheet is the frit 3 (Table I). The assembly (refractory plate + alumina bed + frit bed 1 + decorated sheet + frit bed 3) is subjected to the same heat treatment set forth in example 2.

Claims

CLAIMS 1- Ceramic construction material for cladding facades, floors, and walls, and its manufacturing method, this material being also suitable for any flat surface, suitable for being decorated with a very good aesthetic appearance simulating natural materials such as granite, marble, natural stone or others, characterized in that said material is basically formed by a multilayer slab that has been originated by a suitable thermal treatment of a set formed by several layers of frit grains, of determined compositions and characteristics, among which a Enamel sheet or other material decorated with the desired design, which is visible through the glazing formed by the cooling of molten frits in the heat treatment.

2. Ceramic material, according to claim 1, characterized in that the frits used have a particle size of less than 5000 μm, preferably between 5000 and 600 μm.

3. Process for manufacturing ceramic construction material, according to claim 1, characterized in that a layer of alumina is deposited on the plate of refractory material that completely covers it, and successive layers of frits are subsequently added, intercalating a decorated sheet, subjecting this whole set to a heat treatment of regulated heating and subsequent cooling, after which a polishing phase can be carried out to obtain a spectacular finish of the ceramic slab.

4. Method of manufacturing ceramic material, according to claim 3, characterized in that the heat treatment is carried out by successive heating stages until the temperatures suitable for obtaining the sintering phases are reached, between 750 and 950 ° C, preferably between 850 and 900 ° C, of crystallization or nucleation, between 900 and 1050 ° C., Preferably between 950 and 1000 ° C, and of maturation between 1000 and 1200 ° C, preferably between 1050 and 1150 ° C, with intermediate maintenance times at those temperatures, and with adequate heating and cooling rates for each phase.