A PROCESS FOR MAKING DECORATED CERAMIC TILES

Abstract: The invention relates to a process for realising decorated ceramic tiles. It comprises: association of a decal with a layer of ceramic material in agglomerate or powder form, destined to form a tile, in a tile-forming die for ceramic tiles; pressing the decal and ceramic material to form an unfired tile which on one face contains an image reproduced on the decal; extracting the tile from the die; firing the tile.

Description: Descri pti on . A Process for Making Decorated Ceramic T les. Technical Field. The invention relates to a process for realising decorated ceramic decorations. Specifically but not exclusively the invention is useful for realising tiles in vitrified stoneware and the like. Background Art. Making decorated tiles in vitrified stoneware is done using various techniques. A first of these consists in double-loading the tile-forming die. Double-loading obtains a transfer of a pre-designed decoration on one face of the tile by creating a double layer of material. The described process enables decorations to be made in two colours only, with a resulting poor definition of the desi gns . Another technique for decorating vitrified stoneware tiles obtains the decoration by filling cavities made on the surface of the tiles with glaze. The cavities are made by mechanically removing a layer of material by sandblasting. This is not an easy process to carry out, and is somewhat expensi ve . In a further technique, during the tile-forming phase, a plurality of pockets are created, which are then filled with glaze. This technique is limited in that the obtainable mosaic-type decorations are strictly related to and conditioned by the dimensions and shapes of the pockets . Other techniques still use special soluble salts, which, when ceramic pigments are added thereto, are deposited on the dried and unfired tile. The application is made by means of silk-screening or airbrush machines. These products are able to penetrate to various depths from a few tenths up to a few millimetres into the body of the tile, so that resulting decorations are completely contained within the breadth of the tile itself. In any case the prior art does not teach simple and economical methods for making multi-coloured and well- defined patterns. The present invention, as it is characterised in the accompanying claims, obviates the drawbacks and limitations in the prior art by means of a process for realising decorated ceramic tiles, which process is particularly simple and which can be performed during the tile-forming phase. Further characteristics and advantages of the present invention will emerge from the following description of some non-exclusive preferred embodiments of the invention, illustrated herein purely in the form of a non-limiting exampl e . Disclosure of the Invention. A first embodiment of the process of the invention comprises the following phases in order: loading the die with ceramic agglomerate or powder, destined to form the tile; transferring a decal on to said ceramic material] said decal comprising an image which at first is supported on a support; pressing the above elements to form an unfired tile which on one face thereof contains said image; extracting the tile from the die; fi ri ng the tile. In a slightly modified version of the above process, a layer of vitreous material is deposited above the image of the decal and located on the ceramic material in the die. This layer of vitreous material will after firing be transparent . A further embodiment of the process of the invention is carried out in the following phases: depositing at least one decal, constituted by a support bearing a transferable image, in a ceramic tile-forming die; loading the die housing the decal with agglomerate or powdery ceramic material, which wi l form the tile; pressing the above elements to obtain an unfired tile which on one face thereof contains said image of said decal ; extracting the formed tile from the die; removal of the decal support from the tile; fi ri ng the tile. In the decal the transferable image predisposed on the support is formed by ceramic glazes of various colours, or by coloured clays which during the pressing phase are inserted up to their full thickness into the ceramic material of the tile. The decal support bearing the image to be transferred can be made of paper or of a suitable plastic material. In the first illustrated embodiments said support is removed at the moment of deposit of the decal, and in any case before tile-forming. The material used for the realisation of the tile is, preferably, constituted by a granular or powdery mixture which after firing provides a product exhibiting the characteristics of what is known as vitrified stoneware. After firing, a sanding or polishing operation can be made on the face containing the transferable image of the decal . The invention enables an "inlaid" decoration to be obtained, so that the image or decoration is comprised unprojecti ngl y within the breadth of the tile. According to the desired effects and characteristics, the image of the decal can be obtained using glazes or ceramic clay-based products. An advantage of the invention consists in the fact of obtaining on products such as vitrified stoneware very detailed decorations with regard both to design and colour, without especially complicating the production cycle, and moreover incurring only very limited costs.

Claims: Cl ai ms . 1. A process for making decorated ceramic tiles characterised in that it comprises: association of a decal with a layer of ceramic material in agglomerate or powder form, destined to form a tile, in a tile-forming die for ceramic tiles; pressing said decal and ceramic material to form an unfired tile which on one face thereof contains an image reproduced on said decal; extracting the tile from the die; fi ri ng the tile. 2. A process as in claim 1, characterised in that it compri ses : loading said die with ceramic material in agglomerate or powder form, destined to form the tile; transferring a decal on to said ceramic material; said decal comprising an image which at first is supported on a support; pressing the ceramic material and decal to form an unfired tile which on one face thereof contains said image; extracting the tile from the die; fi ri ng the tile. 3. A process as in claim 2, characterised in that it compri ses : loading said die with ceramic material in agglomerate or powder form, destined to form the tile; transferring a decal on to said ceramic material; said decal comprising an image which at first is supported on a support; depositing above said image on said decal a layer of vitreous material which after firing is transparent; pressing the ceramic material and decal and vitreous material to form an unfired tile which on one face thereof contains said image; extracting the tile from the die; fi ri ng the tile. 4. A process as in claim 1, characterised in that it compri ses : depositing at least one decal in a tile-forming die; said decal comprising a support bearing a transferable image; loading said die with agglomerate or powder ceramic material, destined to form a tile; pressing the ceramic material and decal to form an unfired tile which on one face thereof contains said image; extracting the tile from the die; eliminating the support from the tile; fi ri ng the tile. 5. A process as in claim 1, characterised in that the material used for forming the tile gives rise, after firing, to a product belonging to a category known as vitrified stoneware. 6. A process as in claim 1, characterised in that it comprises, in a phase subesequent to firing, a sanding of the tile face containing said image.

Inventors: BRIGHENTI GIORGIO, BRIGHENTI MARCO, MEGLIOLI ZENO, BRIGHENTI, GIORGIO, BRIGHENTI, MARCO, MEGLIOLI, ZENO
Applicants: BRIGHENTI GIORGIO, BRIGHENTI MARCO, MEGLIOLI ZENO, BRIGHENTI, GIORGIO, BRIGHENTI, MARCO, MEGLIOLI, ZENO
Application year: 1997
Main classification: C04B41
IPC codes: B44C1, C04B41