EP2414306A1

EP2414306A1 - Ceramic tile and method for the production thereof

Info

Publication number: EP2414306A1
Application number: EP10720711A
Authority: EP
Inventors: Ruslan Yun
Original assignee: Petraluxe GmbH
Current assignee: Petraluxe GmbH
Priority date: 2009-03-31
Filing date: 2010-03-31
Publication date: 2012-02-08
Also published as: WO2010112228A1; DE102010013524A1

Abstract

The present invention relates to a ceramic tile (1; 10) having a fine stoneware body (2; 12) (tile body) and a transparent glaze layer (3; 13) that has an optical, prismatic effect, a layer thickness (a), and a smooth, even surface (4; 14), wherein the surface (4; 14) of the glaze layer is designed in a way such that the surface has a reflectometer value between 65 and 90 at a measuring angle of 20°, and the glaze layer thus exhibits an optically prismatic effect. The invention further relates to a method for producing a ceramic tile of said kind.

Description

CERAMIC TILE AND METHOD FOR THE PRODUCTION THEREOF

The present invention relates to a ceramic tile and more particularly to a porcelain stoneware tile having a glazed body (tile body).

Stoneware belongs to the dense silicate ceramic materials and has been known for centuries. It is characterized in that it has a water absorption capacity of less than 2 o wt .-%. Porcelain stoneware is a modern development of this material, from which mostly tiles with very low water absorption (less than 0.5 wt .-% or even less than 0.1 wt .-%) are produced. This very low water absorption makes porcelain stoneware extremely frost resistant. In addition, it has a very good abrasion resistance and high breaking strength, since it is a completely sintered through and very compact material.

It is also known to polish porcelain stoneware after firing to give the surface a high gloss and to imitate surface effects of polished natural stones (eg marble). In this case, the tile body (shards) has consistently the color o resulting from the base material and the addition of pigments in the shards, which are either uniformly or granulated (locally accumulated) distributed therein. Thus, the appearance of the tile body can be adapted to the different natural stones. When polishing, however, press- and fire-related pore spaces are sanded and opened, in which then easily dirt can settle. To reduce the adhesion of dirt, the surfaces are impregnated (eg silane, siloxane, polymer mixtures). However, such impregnating agents have the disadvantage that they can attract and hold certain types of organic dirt and reduce the slip resistance. Therefore, in addition to the unglazed and possibly polished or polished porcelain stoneware increasingly decorated and glazed porcelain stoneware is made. Thus, the most varied decors of natural stones, but also of wood, fabrics, cork or leather can be copied. There are also porcelain stoneware products that combine decorative and embossed 5 relief effects. Since both the usual glazes (layer thicknesses of less than 2 mm) and the applied decors are comparatively sensitive to mechanical abrasion, it can not be ruled out that the visual and haptic quality diminishes after some time despite the almost photographic reproduction of the desired decors. There is also the danger that these - in contrast to the colored porcelain stoneware and the

Natural stone itself - only printed or painted, since the natural, structural depth effect is missing. This effect is particularly noticeable in very colorful and high-contrast decors and especially in structured surfaces.

5 Conventional porcelain stoneware tiles can only be produced in formats of up to 90 x 120 cm and have thicknesses of less than 10 mm. They require when using as facade cladding relatively complex support and suspension structures for surface stabilization, which can be omitted in the paneling with large comparatively strong (from about 3 cm) natural stone slabs. Thus, despite their weight and cost disadvantages, natural stone panels are often preferred over porcelain stoneware tiles.

There is therefore a need to improve the known ceramic products so that the above-mentioned disadvantages are at least partially eliminated. For this purpose, as far as possible, properties should be realized that make them superior to natural stone products.5

It has a porcelain stoneware shard which forms the actual tile body and which is provided on at least one side with a substantially flat (i.e., following the tile surface without local curvatures) transparent glaze layer. This o glaze layer with a smooth, even surface results in a special optical

Depth effect (optical-prismatic effect), which is due to the fact that incident light is hardly scattered in such a glaze surface with a Refleerreterwert between 65 and 90 (at a measuring angle of 20 °), but almost undisturbed by the transparent Layer falls on the visible surface of the cullet, where it is reflected and scattered and passed back through the transparent glaze layer. In each case, upon entering the transparent glaze layer and at the exit thereof, refraction effects occur, which bring about an optical depth effect, which works out the color and surface structure of the shard. If necessary, this effect can be influenced and controlled by transparent coloring of the glaze and by further surface treatment of the glaze surface. The optical and prismatic effect can be further enhanced with the execution of the surface according to claim 2.

The glaze surface may further comprise at least portions according to claim 3, e.g. are processed mechanically, chemically or electrochemically. These may be in particular mechanical grinding or polishing operations, in which the natural glaze surface is further leveled, leveled and / or smoothed. Such treatments are suitable for improving the aspect properties of the visible tile surface on the decorative side. The natural waviness of the glaze surface, which may form during the formation and solidification of the glaze layer, is thus completely leveled or at least partially reduced. The glaze layer is removed only so far that the shards or the decorative surface is not exposed. Surface structures according to claim 4 and in particular according to claim 5 thereby ensure a completely blank surface to the naked eye and enhance the desired optical and prismatic properties.

The further developments according to claims 6 and 7 relate to features which make the ceramic product according to the invention a suitable and advantageous facade element, in which, on the one hand, a thickness exceeding 5 to 30 mm is provided (claim 6) and the dimensions are extended to surface dimensions of up to 1200 x 2400 mm (claim 7). This dimensioning allows large-scale stable facade elements, which have sufficient intrinsic stability and can be hung without overly complex support structures, but nevertheless have weight advantages of more than 65% compared to natural stone slabs. Especially with tall buildings so the entire facade and / or even the building statics can be favorably influenced. The developments according to the claims 8 and 9 relate to features that further increase the design variety. A special decorative layer between the glaze layer and the broken pieces allows a virtually unlimited design variety of the decor side. The decors can be applied in a wide variety of colors, patterns and representations, which are covered, protected and deep-set by the glaze layer. In this case, color decorative effects and relief effects can optionally be combined with each other according to claim 7.

Claim 10 relates to a ceramic product in which the glaze layer is formed from a glaze raw material. Such glaze raw materials can be different transparent and / or colored glasses glass frits or glaze raw material components or even those with certain other defined properties (eg refraction, chemical resistance) which then alternatively or in addition to conventional glaze raw materials (in the form of slip, grits) on the ceramic fragments are applied and melted.

According to claim 11, these glaze raw materials can be arranged in areas or layers with different properties. In a layered arrangement, for example, the surface layer may be formed of a glaze raw material (for example glass frits) which results in a glaze layer of defined (e.g., very high) refractive power, while an underlying layer may be particularly colored. In the case of partially different glaze raw material components, special color and / or surface effects can be achieved by matching the glaze or glaze raw material areas to a particular, underlying pattern or structure or even form a superimposed pattern.

Claim 12 relates to a tile arrangement with porcelain stoneware tiles, which are suitable for floor, ceiling, wall, facade and / or roof arrangements (panels, tiled surfaces, raised floors, etc.).

The claims 13 to 15 relate to methods for producing the ceramic tile according to the invention. The basic method according to claim 13 comprises the steps Providing a vitrified ceramic mass as starting material for the cullet,

- The molding of this mass into a flat strand, for example by means of an extruder in combination with roller assemblies, - Applying the Glasurrohstoffs on the tile blank, for example by

Applying a suitable glaze bead, suitable grits and / or suitable glaze raw materials or glaze raw material components,

- The drying of the tile blank to reduce the residual moisture in the body and in the glaze raw material before firing, - burning the tile blank for sintering the cullet and for melting the glaze layer and optionally the polishing or grinding of the glaze surface to possibly the glaze surface on level and smooth.

Claims 14 and 15 relate to process steps which further optimize the application of the glaze raw material, in which, according to claim 14, alternating glaze suspension and suitable grits or glazes (glaze raw materials and / or glaze raw material components) are applied to apply the requisite glaze raw material layer the desired transparency and surface properties during firing is formed. This can also include more

Intermediate drying steps are provided.

According to claim 15 further edge processing can be provided after firing to produce tiles with very high dimensional accuracy.

Embodiments of the present invention will be described below with reference to the schematic drawings. It shows:

FIG. 1 is a schematic sectional view of a first embodiment of the present invention,

1 a shows an enlarged representation of the region a from FIG. 1, FIG. 2 shows a schematic sectional view of a second embodiment of the present invention, FIG. 3 shows a schematic representation of the method steps for producing the embodiment shown in FIG. 1,

FIG. 4 shows a further schematic representation of a method sequence for the production of the embodiment shown in FIG. 2,

5 shows a schematic representation of an exemplary method sequence for applying a glaze and

Figure 6 is a schematic representation showing a process flow for further surface treatment of the glaze.

o Figure 1 shows a partial cross section through a porcelain stoneware tile 1, the tile body

(Shards) 2 is provided with a glaze layer 3. The glaze layer 3 is transparent, preferably crystal-clear and has a low-insertion fit and has a transparent layer thickness d and is intimately connected to the broken piece 2. The surface 4 is smooth and largely flat. The glaze layer 3 thus forms an optically active body, which makes the surface 5 of the sherd 2 clear and with reinforcing depth effect by its optical properties.

The glaze layer 3 may have different optical properties in terms of area and layer. That it can be different in layers. o refraction properties, colors or even transparency properties are present. This is possible in particular if, for the construction of the glaze layer 3, glasses are used which have glaze raw materials or glaze raw material components with different properties. Such glasses can also be combined with other glaze raw materials. The glasses can also be provided as needed with additives 5, z. B. to the thermal expansion coefficient of the glasses (and thus the

Glaze) on the ceramic shards tune.

FIG. 1a shows the region a in FIG. 1 enlarged and illustrates that the glaze surface 4 can be processed in regions. Here, the unprocessed glaze surface is denoted by 4a o and the machined areas 4b. By the processing, the glaze surface 4 is additionally smoothed and leveled, suitable mechanical methods are, for example, grinding and / or polishing. During this processing, however, it is ensured that a transparent minimum layer thickness d is maintained in order to To ensure that the glaze layer 3 remains closed, so the surface 5 of the cullet 2 is not exposed and does not affect the optical effect, but is reinforced by the leveling of elevations of the natural glaze surface 4.

There are also embodiments (not shown) in which, after the leveling grinding and polishing, the entire surface is again machined mechanically, chemically, electrochemically or otherwise, to influence the reflection, scattering and absorption behavior of the glaze surface 4.

In a further embodiment, the grinding process detects the regions 4b, while the polishing covers all regions 4a, 4b, the transitions 4c are polished or polished and the glaze surface 4 as a whole is smoothed.

The thickness D of the tile body 2 is 5 to 30 mm, preferably 7.5 to 20 mm. The tile body 2 itself is formed from a suitable porcelain stoneware mixture, which may be total or locally colored, in order to achieve irregular patterning and grain effects with a natural stone-like appearance over the entire fragmentary section.

The porcelain stoneware tile 1 has external dimensions of at least 900 x 1800 mm, preferably 1200 to 2400 mm. Porcelain stoneware tiles of this size are suitable for serving as large-area panel elements for facade cladding, which have a high breaking strength with the appropriate thickness D by the dense fragments 2 in conjunction with the glaze structure and can be provided as a replacement for corresponding natural stone slabs.

The glaze layer 3 has technical properties in order to achieve the corresponding optical depth effect. These include e.g. Refraction properties, coloring and transparency.

This optical depth effect is particularly related to the gloss values and the topography data of the porcelain stoneware tile 1 or the glaze surface. The following Tables 1 and 2 give reflectometer values (gloss measurement) according to DIN 67530 or topography data for a tile according to the invention (Petraluxe) in comparison to conventional tiles (pattern 1, pattern 2), the inventive tile and the conventional tile being polished in conventional methods ,

Table 1 (gloss values according to DIN 67530):

Measuring angle Petraluxe pattern 1 pattern 2

20 ° 79.3 36.3 56.4

Table 2 (topography data)

) = According to EN ISO 4287, measuring area 10x10 mm, 500 lines, 100 Hz after polynomial incorrection 3rd degree, FRT Microprof

² ) = According to EN ISO 4287, measuring area 10x10 mm, 500 lines, 100 Hz after 3rd degree polynominal correction and filtering with Lc = 0.800 mm, FRT Microprof Further investigations have shown that the desired optical and prismatic depth effect is particularly correlated and additionally supported with gloss values at a measuring angle of 20 ° between 65 and 90, when at the same time the values for the reduced peak height (sRpk) are 0.5 μm and which for a reduced depth of groove (sRvk) is less than 1 μm. The effect is even more pronounced for reflectometer readings of more than 75 (measuring angle: 20 °). Reduced tip heights of less than 0.2 μm and reduced groove depths of less than 0.5 μm have also proven to be advantageous.

FIG. 2 shows a second exemplary embodiment of a ceramic product according to the invention, namely a porcelain stoneware tile 10, which likewise has a tile body / shards 12 and a glaze layer 13. However, a decorative layer 16 is additionally formed here between the glaze layer 13 and the broken piece 12. This decorative layer 16 is formed in the region A of a color layer 18 which is applied to the surface 15 of the cullet 12 5 and is completely covered by the glaze layer 13.

In region C, the decorative layer consists of a relief structure 20, which is embossed in the surface 15 of the cullet 12. The glaze layer 13 completely fills the relief recesses 21 and is formed over the relief protrusions 22 with the desired minimum layer thickness d.

In region B, the relief structure 20 is combined with a color layer 18. Depending on the design can be simulated with a correspondingly applied decorative layer 16 (variant A, B or C) almost any color, pattern and texture impression of any material - 5 surfaces and through the glaze layer 13 with its smooth levels

Surface 14 are visually highlighted and permanently and reliably protected against contamination and environmental influences. Again, the glaze surface 14 may be additionally processed as explained in connection with FIG. The dimensions (thickness, size) correspond to the areas indicated in connection with the first exemplary embodiment.

The method for producing the ceramic products according to the invention and in particular the porcelain stoneware tiles 1, 10 will be explained with reference to FIGS. 3 to 6. FIG. 3 shows the basic sequence of the method:

(1) First, a plastic ceramic mass is provided. This is going out

5 clay raw materials and hard materials (feldspars and / or chamottes) formed according to the desired properties of the later porcelain stoneware tiles 1, 10 (strength, dimensional stability, color, water absorption, porosity) in the desired mixing ratios with water to a suspension and, for example, in a Spray tower to (spray) granules are processed with a o moisture between 5 and 9% by mass. These spray granules are then additionally mixed with water in a mixer in order to obtain an extrudable mass with a moisture content between 14 and 18% by weight. Possibly. Plastication aids such as lubricants and surfactants are mixed in order to adjust the plasticity of this ceramic mass so that a plate can be extruded up to a width of 1400 mm in an endless strand.

(2) The vitrified ceramic mass is molded by means of an extruder whose mouthpiece width is tuned to the raw plate width of up to 1400 mm. o In addition, the distance of the mouthpiece to the end of the extruder screws is coordinated so that a steady error-free bildsamer extrusion strand is discharged from the mouthpiece. Possibly. adjustable or exchangeable mouthpieces should be provided for different strand widths and thicknesses. In addition, when extruding the ceramic mass, the outer edges can be increased 5 to be formed during firing, the melting of the glaze layers in the

To prevent or at least reduce edge area.

(3) The plastic (still plastic) strand is cut to the desired roughness (e.g., width 1400 mm, length 2700 mm). 0

(4) The glaze material is applied to the plate blanks. For this purpose, wet processes can be used in which glaze suspensions are sprayed onto the ceramic surface (eg by compressed air or by airless spraying using suitable spray guns or nozzles). The suspension contains glaze particles in suitable grain bands as solid phase (here further details if necessary). The desired glaze thickness is achieved by applying several layers one above the other, possibly with different grain bands. The cavities between the individual glaze particles are closed during the fire by the glaze particles melting and melting together. Emerged bubbles ideally emanate at the glaze surface. 0

In another wet process, the tile blank passes through a "waterfall" of glaze slurry produced by means of a glaze bell, which allows for a very smooth and uniform glaze surface, and drying steps can be provided between the individual application steps.

The glaze material can also be applied by dry process. These are grits with glaze constituents (frit, matting agent and color body) for producing a low-bleach transparency or glaze These grits are mixed in different grain bands, so that the raw glaze in the required thickness and sufficient density (packing density of each Glaze granules) is set low in cavities.

Instead of the classical glaze suspensions (glaze slip), which are applied in the wet process, and the so-called grits, which are applied by dry process, glasses (glaze raw materials or glaze raw material components, especially also so-called glass frits) can be applied in similar processes.

o In order to stabilize the glaze structure on the edge, the glaze material is supported with suitable glues to ensure a uniformly thick glaze over the entire tile surface. For the construction of stable raw glaze layers of glaze material, the wet and dry processes can also be combined. FIG. 5 schematically shows such a sequence in which glaze suspension (slip) is first applied and then grits are applied or spread in a dry process. 5 This is followed by a drying step. The cycle can be repeated several times.

However, there are also other processing cycles in which the steps slip application, Gritauftrag, drying in other suitable sequences repeatedly or o simply run.

In another process, the glaze is applied only after drying (5) of the raw tiles and a possibly applied in a wet process Rohglasur with several provided in the production line Gritaufgabe- 5 devices, each order strengths possibly with different grain bands between 0.2 and 2 mm can be realized.

For glaze raw materials, the usual grain sizes are between 0.1 and 1 mm. Grains below 0.1 mm are called glass powders. By suitable o mixture and alternate application of different grain sizes can

Cavities are kept low in this raw glaze.

By means of these process steps for applying the raw glaze transparent glazes in a layer thickness between up to 6 mm or even 5 above can be achieved.

(5) During drying, water is removed from the raw tiles at a temperature of approx. 70 - 150 ° C (residual moisture content below 0.5% by mass).

o (6) The raw tiles with the glaze material are fired in roller kilns designed for the corresponding large formats in a single firing (about 1100 - 1300 ° C for 1 hour). The tile blank sinters to the tile body / shards (2; 12) and the glaze raw material melts bubbles and waves with high gloss to the glaze layer (3; 13) and combines with the shards (2; 12).

(7) Subsequently, optionally, a further surface treatment takes place, which according to FIG. 6 comprises at least one polish (optionally in regions) of the glaze surface. The polish may also precede a leveling grinding process. For a glossy or high-gloss surface, appropriate roughness should be achieved after polishing. Possibly. For example, further surface finishing techniques may be used after the polishing to achieve particular optical surface effects, or may also be applied, e.g. to increase the skid resistance of such tiles (1; 10). Other mechanical processing methods (e.g., sandblasting) are suitable, as well as chemical methods (etching) to matt or satinize the surfaces.

5 Other optional process steps can be edge processing to improve the dimensional accuracy (accurate cutting) or to improve processability (chamfering).

FIG. 4 shows that a decorative layer can be applied or formed between the cutting of the tile blanks (3) and the application of the glaze material (4).

This so-called decoration allows the exact representation of rock structures and color patterns on the surface of the cullet (cf., FIG. 2), which in combination with the glaze described above comes into its own in a very high brilliance. The decoration, like the glaze before drying (5), can be applied to the leather-hard ceramic shears and / or on the dried shards immediately before the

Fire (6).

For this purpose, for example, natural stone decors are realized according to the "Rotocolor" process, whereby the selected rock patterns are scanned and "baked" in the "Rotocolor" rolls o made of synthetic material.The decorative colors (a mixture of ceramic colors) are then applied over several rolls in series 2), which is then subsequently covered by the glaze raw material Color of the desired colors to end decoration, which remains visible under the transparent glaze layer.

Additionally or alternatively, mixtures of ceramic colors and thermoplastics can also be applied by rotary screen printing. Here, the decor pattern is defined by sieves, by means of which a warmed and thus processable screen printing ink is pressed onto the tile surface with a squeegee. This method makes it possible to print up to eight colors one behind the other extremely precisely. Besides these two common decoration methods, other suitable ceramic decoration methods can also be used.

Additionally or alternatively to the above-described decoration method, in which color layers (18) are applied, also relief pattern (20) can be embossed in the still soft or leather-hard tile body and that via suitable die 5 or rollers whose embossing reliefs either directly from corresponding Molded surfaces or indirectly produced by suitable scanning and processing methods.

The process alternatives described above all relate to the so-called single-burn process, in which the chips sinter out in a single firing process and the glaze o melts. This method is inexpensive due to the low energy consumption.

In the so-called Zweifachbrandverfahren first an undecorated or partially decorated fragments is prefired. This so-called biscuit shard is then further decorated and provided with glaze material and then fired again to melt the glaze (about Ih at about 1000 ° C). This second firing takes place at slightly lower temperatures than the first firing. Although this increases the energy requirement, but has the advantage that the temperature can be matched precisely to the melting behavior of the glaze or the glasses and / or the limit temperatures of the decorative color pigments. 0

In a further (not shown) method, it is also possible Biscuitscherben (decorated or undecorated) with a trained as a glass glaze layer (also decorated or undecorated) to occupy and this at comparatively low To connect temperatures with the broken pieces. The glaze disc only has to be heated to such an extent that its underside, which is adjacent to the surface of the cullet, softens so much that it sinks or melts into the cullet pores, thus forming a firm, inseparable bond with the cullet. A fusion of the glaze with each other 5 is not required here. There are also methods (not shown) in which a heated, softened and deformable glass layer is mounted on a preheated shard, which then joins together during co-cooling therewith.

Further variations and embodiments of the invention will be apparent to those skilled in the art from the following claims.

Claims

A ceramic tile (1, 1 1) having a porcelain stoneware shard (2; 12) (tile body) and a transparent, largely flat glaze layer (3; 13) having a layer thickness (d) and a smooth surface (4; 14), wherein the surface (4; 14) of the glaze layer is formed so as to have a reflectometer reading of between 65 and 90 at a measuring angle of 20 ° and thereby the glaze layer exhibits an optical-prismatic effect.

A ceramic tile (1,1,1) according to claim 1, wherein the surface (4; 14) has a reflectometer reading of greater than 75 at a measuring angle of 20 °.

3. Ceramic tile (1, 11) according to claim 1 or 2, wherein the glaze surface (4, 4a, 4b; 14) at least partially processed, in particular ground or polished.

4. A ceramic tile (1, 11) according to claim 1, 2 or 3, wherein the glaze surface (4, 4a, 4b; 14) and in particular the machined areas (4b) have a surface structure such that a mirror-smooth surface is formed, which is a reduced one Peak height (sRpk) of at most 0.5 μm and / or a reduced groove depth (sRrk) of at most 1 μm.

A ceramic tile (1,1,1) according to claim 4, wherein the glaze surface (4,4a, 4b; 14) has a reduced peak height (sRpk) of at most 0.2 μm and / or a reduced groove depth (sRrk) of at most 0 , 5 microns.

A ceramic tile (1, 11) according to any one of claims 1 to 5, wherein the body (2; 12) has a thickness (D) between 5 and 30 mm.

7. A ceramic tile (1, 11) according to any one of claims 1 to 6, wherein the cullet (2; 12) is planar and has a width of 900 to 1200 mm and a length of 1200 to 2400 mm.

8. ceramic tile (1, 1 1) according to any one of the preceding claims, wherein between the shards (12) and the glaze layer (13) a decorative layer (16) is arranged.

9. ceramic tile (1, 11) according to claim 8, wherein the decorative layer (16) as a decorative color (18) and / or relief structure (20, 21, 22) is formed.

10. Ceramic tile (1, 11) according to one of the preceding claims, wherein the glaze layer (3; 13) has a, in particular transparent and / or colored, glaze raw material or such a glaze raw material component.

11. Ceramic tile (1, 11) according to claim 8, wherein a plurality of glaze raw materials or glaze raw material components, area and / or layers, the glaze layer (3, 13) form.

12. tile arrangement, in particular floor, ceiling, wall, façade or roof arrangement with at least one ceramic tile (1, 11) according to one of claims 1 to 11.

13. A method for producing a ceramic tile (1, 11) according to any one of claims 1 to 11 with:

Providing a plastic ceramic mass;

Forming the viscous ceramic mass into a strand;

Cutting the extrusion strand into a tile blank;

Applying the glaze raw material to the tile blank;

Drying the tile blank;

Burning the tile blank; and optional

Polishing or grinding the glaze surface.

14. The method of claim 13, wherein applying the glaze raw material comprises: alternately applying a glaze suspension (slurry) and applying grits.

15. The method according to any one of claims 13 and 14, wherein after firing or after polishing an edge processing is provided in which the tile edges are trimmed and / or ground.