DE7403561U - Partly glazed ceramic tile - Google Patents

Description

I * · · · · UM Il

Patentanwältje Dipl.-Ing. H.Weickmann, Dipl.-Phys. Dr, K. Fincke

,. Dipl.-Ing. EA.Weickmann, Dipl.-Chem. B. Huber ; Dr.-Ing. H. Liska

8 MUNICH 86, DEN

PO Box 860 820

MÖHLSTRASSE 22, CALL NUMBER 98 3921/22

CWI

AGROB AKTIENGESELLSCHAFT

8000 Munich

Partly glazed ceramic tile

The innovation concerns a partially glazed ceramic tile. A method of making such tiles is known from Keramische Zeitschrift, Volume 25, No. 8, 1973, p. 393. In the known method A layer of glaze powder is applied to the unpressed base material. The molding compound and the powdery one Glaze masses are then pressed together. This creates tiles in which the glaze surface of Breakthroughs of unglazed particles of the matrix is interrupted.

The innovation is based on the task of producing a tile whose visible surface is raised, glaze-free Has visible surface areas and next to them sunk, glaze-bearing visible surface areas.

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To solve this problem it is proposed according to the innovation, that the visible surface has raised unglazed visible surface areas and next to it recessed, glazed visible surface areas, The body is sintered to a greater density under the glazed visible surface areas than under the raised, unglazed visible surface areas.

The advantage of the tile according to the invention is that it can be used without the use of mechanical profiling The raised, glaze-free areas ensure good slip resistance and, thanks to the recessed, glazed areas, a high level of safety Has wear resistance, with the decorative effect of a glazed tile despite the unglazed areas is retained or is even reinforced by choosing a suitable pattern.

It is already known to apply glazes in patterns to unglazed tiles in order to achieve decorative effects; the glazes are applied as liquid glazes. To ensure the regularity of a pattern, the glazes must be adjusted so that they do not flow beyond the limits of the pattern. It turns out that the surface of the glaze is usually higher than the unglazed areas after the tiles have been fired. Such tiles can therefore, from their step behavior, with the tiles produced according to the invention, in which the glaze-bearing visible surface areas are lower than the glaze-free surface areas, cannot be compared.

It is also known to achieve decorative effects and to increase the slip resistance profiled, unglazed Tile to glaze in the depressions, while the elevations by a protective film or by wiping or sanding

must be kept or made glaze-free before firing. You need profiled tools and special ones Precautions when glazing, so that the production of these tiles is less favorable than the process sequence Manufacture of tiles according to the innovation.

The production of tiles according to the innovation can be done in such a way that a tile base and one of the Tile base mass superimposed glaze mass are dry-pressed, the glaze mass after pre-pressing the base material is sprinkled on in partial areas of the visible surface and the pre-pressed blank with the sprinkled Glaze mass is then finish-pressed in several stages if necessary.

The pressing, optionally multi-stage pressing, can be carried out in such a way that initially through a relatively light pressing the dry glaze powder is fixed on the pre-pressed base, so that it is in place at the later final pressing operation, which can be carried out on the same press and place remains.

In the last pressing stage of the final pressing, such a pressure is preferably applied that that provided with the glaze The surface leaves the press completely flat. If this surface is flat after the last pressing stage, then so are - as the applicant has established - by a produced when using conventional glaze masses, reinforced Shrinkage of the matrix in the glaze-bearing area the glaze-bearing visible surface areas inevitably countersunk opposite the glaze-free visible surface areas.

0206

The base material should be pressed in a manner customary in the tile industry with a moisture content of approx. 5%; the dry glaze must have a certain lower moisture content that is matched to the base mass z. B. 3%.

In order to achieve the effects according to the innovation, it is advantageous to initially apply the Grunditiasse with a pressure of

490.5 N / cm and ¹ at least in the last

2 stage of the final pressing a pressure of 3433.5 N / cm apply.

An explanation for the result achieved according to the innovation can be seen in the fact that the glaze is pressed in penetrates into the already pre-compressed base material so far that both the Both the glaze and the base mass have a stronger sintering and therefore shrinkage due to the presence of the glaze mass suffers.

The desired effect of the level difference adjustment between the raised, unglazed visible surface areas and the sunken, glazed visible surface areas occurs particularly clearly when a feldspar-free, or Feldspar base mass with less than 3% alkali oxides and less than 15% Al-0, in connection with a glaze mass is used, which at least 40% flux in the form of feldspar, preferably potassium feldspar, calcite or dolomite contains. The percentages are to be understood as percent by weight. As a feldspar-free base material in the sense of the innovation a basic mass is to be understood that contains 0.5 to 1.5%

Contains alkali oxides, this alkali oxide being introduced into the mass via the clay components.

The dry glaze can be spread irregularly from plate to plate with a spreader, but with a similar character or sprinkled onto the pre-pressed base material blank according to a defined decorative pattern. The sprinkling according to the decorative pattern z. B. be done by means of a template which is underlaid by a slide, the Dry glaze is first carried by the slide and by pulling the slide out from under the template then caused to fall onto the pre-pressed blank.

Tiles according to the innovation can be produced in which the raised, glaze-free visible surface areas together

2 represent hanging surfaces of the order of 1 cm and above, the geometrical shape of these surface areas can be anything. The recessed, glaze-bearing surface areas can be much smaller,

for example down to 0.1 cm. over a whole side of the tile considered, the ratio of the sum of the glaze-bearing, recessed visible surface areas to the sum of the Glaze-free, raised visible surface areas, for example be between 1: 9 and 4: 1.

An example of a glaze composition is the following mixture:

Potassium feldspar 28.4%

Calcite 7.0%

Dolomite 8.5%

Kaolin 11.4%

Sand 23.8%

• »·· ■ ft ··

Zinc oxide 8.0%

Zirconium silicate 9.2%

Zirconium oxide 2.7%

Bentonite 1.0%

100.0%

For an explanation of the innovation, reference is made to the accompanying drawing; in this represent:

1 shows a section through a first embodiment of a tile according to the innovation,

2 shows a section through a second embodiment of a tile according to the innovation,

3 shows an enlargement of the transition points between a glazed and an unglazed one Area and

Fig. 4 is a plan view of a tile according to the innovation

In Fig. 1, the body is denoted by 10. On the visible side of the body you can see raised, glaze-free Visible surface areas, which are designated by 12 and recessed glaze-bearing visible surface areas that are denoted by 14. The level difference compared to a common reference plane parallel to the main plane of the tile is indicated by the measuring arrows a and b, the difference in length b - a of which is 0.01 to 0.3 mm. The embodiment of the tile according to FIG. 2 differs from

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those after Pig. 1 only in that the shard 110 is provided with a profile 116 on its underside which can be beneficial in terms of tile laying. The structure of the cullet material in the volume regions 20 and 120 delimited by dashed lines, it is more densely compacted by sintering than in the other volume ranges.

Fig. 3 leaves a transition zone 18 between a raised, non-glazed visible surface area 12 and a sunk recognize glazed visible surface area 14.

4 shows how the raised, non-glazed visible surface areas 12 and the lowered glazed ones Visible surface areas 14 result in an image in the manner of a lake landscape.

The visual surface level difference between the raised and the recessed visible surface areas is generally 0.01 to 0.3 mm, preferably 0.1 to 0.2 mm.

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Claims (4)

Protection claims 1. Partially glazed ceramic tile, characterized in that that the visible surface raised unglazed visible surface areas and next to it recessed, glazed visible surface areas having, wherein the body is sintered to greater density under the glazed visible surface areas than under the raised, unglazed visible surface areas. 2. Tile according to claim 1, characterized in that the visible surface level difference between the raised and the recessed visible surface areas 0.01 to Q.3 mm, is preferably 0.1 to 0.2 mm. 3. Tile according to claim 1 or 2, characterized in that it consists of a feldspar-free or feldspar poor Base mass with less than 3% alkali oxides and less than 15% Al-O, and consists of a glaze mass, which Contains at least 40% flux in the form of feldspar, preferably potassium feldspar, calcite or dolomite. 4. Tile according to one of claims 1 to 3, characterized in that that the glaze is applied irregularly or according to a decorative pattern. 7403561 05/24/78