US3796618A - Method of decorating ceramic wall and floor tiles - Google Patents

Abstract

In decorating ceramic elements, such as wall and floor tiles, a solvent is sprayed on a raw-glazed tile as it travels on a conveyor member. Next a pattern of ceramic dyes printed on a carrier element, and with a lacquer coat on the surface opposite the carrier element, is placed on the tile with the lacquer coat in contact with the tile. The solvent previously applied to the tile dissolves the lacquer coating. Then, in turn, the pattern is pressed against the tile and the carrier element is removed before the tile is baked.

Description

March 12, 1974 LfiHMlNg ETAL 3,796,618

METHOD OF DECORATING CERAMIC WALL AND FLOOR TILES Filed April 22, 1971 ATTORN Y5 United States Patent Oflice 3,796,618 Patented Mar. 12, 1974 3,796,618 METHOD OF DECORATING CERAMIC WALL AND FLOOR TILES Giinter Lehming and Gerhard Kiippers, both of 19 Breslauerstr, 6601 Schafbruecke, Germany Filed Apr. 22, 1971, Ser. No. 136,383 Claims priority, application Germany, Apr. 23, 1970, P 20 19 748.2 Int. Cl. C04b 33/34 US. Cl. 156-89 ABSTRACT OF THE DISCLOSURE 6 Claims SUMMARY OF THE INVENTION The invention concerns a method for machine-decorat ing ceramic wall and floor tiles and a device for carrying out the method.

It is known to decorate wall and floor tiles automatically by screen printing. In this direct printing technique, it is only possible to utilize relatively coarse drawings, due to printing difficulties and the resulting register differences. In a multicolor print, the register difierences become so considerable that the decoration loses its appeal. Since screen printing presses can only print the plane surface of the tile and the tile has a significant curved surface over 1-3 mm. at its edge zones, it is not possible with this technique to apply the decoration over the entire surface of the tile. In laying such decorated tiles gaps result which make a continuous picture or pattern quite unattractive.

It is also known to decorate tiles manually by applying decals or the like which embody the pattern or design to be placed on the ceramic article. Depending on the choice of colors, the tiles are baked at 720 C. (glaze-on decoration) or at about 1050 C. (glaze-on decoration for intensive fire). The decorations obtained in this manner are more or less resistant to abrasion and chemical influences. Contrary to screen printing decoration, this decorating technique avoids the disadvantages of leaving the edges undecorated, since the decals can be made large enough so as to allow decorating of the curved edges as well. The main disadvantage of this decorating technique, however, is that each decal or pattern has to be placed individually by hand and that, moreover, the excess water transferred in the process has to be removed by a rubber or plastic squeegee-like member for preventing baking defects. Such manipulations are expensive and timeconsuming and, therefore, limit the application of this decorating technique to very expensive high style decorations.

Accordingly, for a long time the tile industry has been looking for a mass production method of automatically applying attractive decoration to tiles. Such a method has to combine the advantages of automatic screen printing decoration and the advantages of manual decal decoration. The use of the known decals or patterns for machine decorating so far has failed due to the fact that these patterns, after removal from the carrier paper, can not be manipuplated by machine, since they then lack the necessary stability. One the other hand, if these patterns are applied together with their carrier paper onto the tile,

the pattern comes oil the tile again or is at least displaced when one tries subsequently to remove the carrier paper from the pattern. All attempts in this direction have shown again and again that patterns or decals are not suitable for the automatic decorating of ceramic articles generally and for wall or floor tiles in particular, and it is always necessary to revert to the manual decorating techniques.

The present invention has as its object to disclose a process for machine decorating ceramic wall and floor tiles with patterns of ceramic dyes.

Therefore, in accordance with the present invention, ceramic articles are decorated by utilizing decal-like members containing a design or a pattern of ceramic dyes printed on a carrier element which is provided with a water-soluble and/or meltable separating layer and bonded by at least one lacquer coating. Initially, the raw-glazed tile is sprayed with a solvent for dissolving the lacquer coating, the pattern is then placed on the sprayed surface and the gloss and decoration baking is effected in one working step. It is the particular merit of the invention to have recognized for the first time that with this special pattern, which, on the one hand, is printed onto an easily removable carrier and, on the other hand, is bonded by a lacquer mask, a decorating process is available which is suitable for automatic machine decoration of wall and floor tiles. This suitability is based on the fact that the adherence between pattern and tile, on the one hand, and between pattern and carrier paper or element, on the other hand, is basically different. Whereas the bonding between pattern and carrier paper is effected by a water-soluble and/or meltable separation layer, such as, a polyglycol layer, the bonding between the pattern and the tile is effected by the application and subsequent penetration of the lacquer mask and/or the ceramic dyes into the raw-glazed tile. The latter bonding is so intensive that when the carrier paper is detached and subsequently removed from the pattern applied to the tile,there is no danger of removing the pattern with it or even displacing it. This is one of the basic reasons for the suitability of the inventive procedure for machine-decoration of tiles.

A further decisive advantage is to be seen in the fact that due to the difiierent adherences the pattern can remain connected with the carrier paper during the applivcation to the tile and the pattern therefore retains the stability which is necessary for machine manipulation.

Another advantage is the non-hygroscopic nature of the lacquer mask. If water is used for dissolving the separating layer between the pattern and carrier paper, the lacquer mask protects the underlying water-sensitive raw glaze. If, in a further development of the invention, the carrier of the pattern is a polyglycol-coated paper which is removed from the pattern by water, the lacquer coating and the polyglycol layer dissolved in water repel each other due to their contrasting non-hygroscopic and hygroscopic nature, which facilitates the removal of the carrier paper in an advantageous manner.

As a suitable embodiment of the invention, it is suggested that the raw-glazed tile is subjected to the following consecutive steps:

Spraying the raw-glazed tile with a solvent for dissolving the lacquer coating, applying the pattern so that its lacquer coating contacts the tile, pressing the pattern on the tile, and dissolving and removing the carrier member from the pattern. In carrying out this process the tile is placed on a conveying device and passes, in

sequence, a spraying device for the solvent, a dispensing device coacting with a supply container for the patterns which applies one pattern to each tile, at least one pressure roller which presses the pattern onto the tile, and a device for dissolving and removing the carrier from the pattern.

In cases where -it is-not suitable to worl wit water s h... 9 .i!1 .59 the. separat layer b t n. P me a.

paper, the heated 'waterpenetrates thepolyglycol layer and s of tens this layer within seconds.

and carrier, it is suggested, according to the invention, that the carrier of the decal -or pattern be a wax-coated heat conducting toil .whichis removed from the pattern by the influence of heat,

In a further embodiment of fth'e .inventionj, it is gested thatthe lacqu erhcoat beslightly larger than the tile to be deco.r ated. 'I.'his..oife.rs fvery .goodlp against water influencje s for theraw glaze layer 9' BRIEF DESCRIPTION OF" THE. nRAvv'rNo f The-drawing is-T a schematic illustration of one-embpdiment for carrying'out the invention.

'DETAILED DESCRIPTION OF THE INVENTION As shown in the drawing, an elongated conveyor belt 1 moves raw-glazed ceramic tiles 2 in the direction indi cated by'the arrow. The tiles 2 are securedin'position on the conveyor belt 1 and are carried first, pasta spray device 3 which contains ethylglycolacetate as a. solvent. Next the tiles moveunder a storage container 4' forpatterns 5 of ceramic dyes from which a device 6 dispenses the patterns 5. In turn the tiles 2 travel under pressure rollers 7 to 10 by which the patterns arepressed jonto the tiles 2. After leaving the rollers the tileslZj arelspra by a second spraying device 11 containing heatedwater." Finally the tiles move under a further pres'sure'roller' 1'2; and a sponge member 13. Below .thef spraying device a collecting container 14 is providediwhich coj ectsthe; excess solvent and recycles it to the spraying'd e for further use. In addition, a collecting container 15 'fo r the excess water is arranged below the sprayjrneans 11, the pressure roller 12 and the sponge member 13.

In the storage container 4, the patterns S'are stacked so that. the lacquer coat bonding the pattern is dire'cted downwardly and, accordingly, the polyglycol-coated paper acting as a carrier is directed upwardlyg The di pensing device 6 includes arubber roller whose rot'a drive is coupled with the driveof the .conveyor belt, not shown. When rotating, the ,rubber roller 6 fpushes" the lowermost pattern 5 from the storage,containerfiinthe direction of travel-of the conveyor'helt 1 between a" pair of rollers16, which'jdirectthe pattern 5 over a rolle'r 1"] to an abutment ls where the tile 2 to be deco r U As soon as the tile 2 and jthe patter'n 5f n regi er with one another, th'e'abutin is 1re ov d and the 18 tile. with the pattern is conducted along I belt 1. The pressure roller '7 then presses h onto the tile} so that the solvent, ethylgly the raw-glaze is applied to the ila'oqu'er coat and' 'the ceramic dyes of the pattern. This' application procedure is continued during the passage of tile with its pattern under the additional pressure rollers 8,9 and lfllf'The lacquer coat or layer and the ceramic dyes thus enetrate into the raw-glazed tile establishing aifihtimatebond between the pattern'and tile. Subsequently, as the tile "2 with the'patterns moves under the second spray device 11 it is sprayedc'with heated water on the polyglycol-coated carrier 'rpaper; facing upwardly; Due to the absorbencytof.-;-the.carrier The tileZ is thereupon movedlpast the further pressure roller 12 which removes the excess water on the carrier paper. The carrier paper is then removed by the sponge member 13. This sponge member has the shape of a rotation roller ,whose tangential direction of movement forms a right angle with the direction of movement of the tile Z-and/or the conveyer belt 1. It is also possible, however, that-the two directions of movement form any other angle. Theiright angle is the most suitable because the removed carrier'paper in that case cannot fall back on the conveyer belt 1. After the sponge member, the decorated tiles 2 then reach storagechambers where they are stored until the baking step.

If, insteadof the polyglycol coated paperas carrier for the ceramicpattern, a wax coated, heat conductive foil is used, the spraying means 11, pressure roller 12 and the sponge band 13 are replaced by a heat source whose radiation is directed on thefoil and a blower which directs the foil away from thepattern. In this case it is particularly suitable tocombine the heat source and blower in a single device, such; as, in a hot air producing drier unit.

Instead of the elongated conveyer belt 1, it is of course 7 possible to provide a revolving conveyer for the tiles 2.

. If the pattern 5 is slightly larger than the tile 2 so that at least one of the four edges 'can also be decorated,. at least one of the pressure rollers 7 to 10 has to be designed such that it contacts the edges of the tile.

It is the possibility of edge decoration of the tiles which bringsparticular advantages to the inventive procedure as compared to screen printing decoration. By uisng the specially printed ceramic pattern it is moreover possible to do pre-sorting in the printing location, which makes the number of rejects in the decorating stage considerably smaller than in the direct printing procedure. Since no restrictions have to be made for ceramic multicolor printing on paperin respect to register and number of colors, it is possibleto create considerably more attractive decorations than in direct printing procedures. I r A further important advantage of the inventive procedure is thatby the penetration of the pattern into the raw glaze -*a decoration can be achieved which is c0rnpletely" equal in resistance to abrasion and chemical influences to the much more expensive below-glaze decorationaThis-i's of particular importance 'for floor tiles.

1? What is claimed is:

1. Method of decorating a raw-glazed ceramic tile with I a pattern of ceramic dyes printed on a carrier element provided with a separating layer between the carrier ele 'ment andthe patternand with a lacquer coating on the surface of thepattern opposite the separating layer for bonding the pattern, wherein the improvement comprises subjecting the raw-glazed tile in succession to the steps of positioning the raw-glazed tile on a travelling support surface with the'surface of the tile to be decorated directed upwardly and conveying the tiles along a path of travel for sequentially effecting the decorating process at spaced stations along the path of travel, spraying a solvent on the surface of the'raw-glazed tile to be decorated which solventis capable of dissolving the lacquer coating on the pattern, automatically depositing and positioningthe pattern on theupper surface of the tile and applying the pattern so that the lacquer coating on its surface contacts the solvent sprayed on the surface of the raw-glazed tile and carrier element located on the face of the pattern dir'eoted "outwardly from the tile, dissolving the lacquer atingon' thepat tern by means of the solvent and afford- ;s ubsequent penetration of the lacquer coating the ceramic dyes into the raw-glazed tile, pressing erjn against. the surface of the tile, separating the relement from the pattern,- removing the carrier element-,lfrom' the patternon the tile, and gloss and decoration halting ,the-tile in a single operation.

2. The method, as set forth in claim 1, characterized therein that the carrier element on the pattern is a polyglycol-coated paper, and using heated water for separating the carrier element from the pattern.

3. The method, as set forth in claim 1, characterized therein that the lacquer coating is slightly larger than the surface of the tile being decorated.

4. The method, as set forth in claim 3, characterized therein that the size of the pattern is slightly larger than the surface of the tile being decorated so that at least one of the four edges of the tile can be covered by the pattern.

5. The method, as set forth in claim 1, characterized therein that the carrier element of the pattern is a waxcoated heat conducting foil, and applying heat to the carrier element separating the carrier element from the pattern.

6. The method, as set forth in claim 5, characterized therein that after separating the foil from the carrier element applying a stream of hot air over the tile for removing the carrier element from the tile.

References Cited UNITED STATES PATENTS 11/1961 Akkeron 156-89 2/1953 Rathke 156-89 X 1/1962 Gobel 1173.1 10/1949 OHara l25--24 X l/l961 Porth 15689 10/ 1970 Bailey 117--3.4 9/1934 Swift 161-223 5/1969 Milliken 156-89 3/1971 Hoad et a1. 16l-406 X GEORGE F. LESMES, Primary Examiner 15 H. F. EPSTEIN, Assistant Examiner US. Cl. X.R.

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