Method for producing conglomerated plates for coating floors, etc.

Description

[0001] The invention relates to a method for producing slabs or tiles of any size from a conglomerate of rock material, in particular for lining floors, walls or the like. The invention also relates to the slabs produced according to this method.

[0002] The invention relates in particular to a method for producing slabs for the specified uses, which consist at least partially of an agglomerate of valuable stone, for example marble. The binder generally consists of cement, and the outer surface, which is smoothed and polished, forms the visible surface of the floor or wall lined with the slabs. The slabs are produced by pressing the conglomerate mixture into suitable molds with a flat bottom.

[0003] It is known that the production of these slabs by pressing has significant advantages over conventional methods of natural drying of the conglomerate mixture, whereby excess water is removed by evaporation during drying. The pressing process greatly accelerates production, and the mixture becomes denser. It is also known that, when producing the slabs under pressure, it is necessary to apply a dry or nearly dry agglomerate, consisting of sand or less expensive granular material and a small amount of cement, to the layer of granular or small-aggregate valuable rock material that is first applied to the bottom of the mold. This second layer has the following two functions: 1.1. to absorb the excess water of the mixture of the first layer in order to enable compaction during the pressing process, so that less time is required for the conglomerate to solidify, and 2. to form a layer bonded with the layer of valuable agglomerate, thereby increasing the thickness of the manufactured slab and ensuring that it has sufficient mechanical strength to be able to be pulled out of the die, and also allowing, if the mixture has not yet dried and hardened, the surface of the body to be smoothed and polished with known suitable grinding machines, whereby the slab is subjected to great vibrations.

[0004] The slabs produced by this method are too thick and therefore have significant disadvantages. Their high weight relative to their surface area increases transport costs from the place of production to the place of use. Handling and transporting the slabs to the place where they are used for floors or walls is cumbersome and expensive. Their weight necessitates the installation of special devices for their fastening, particularly on stone walls. The layer of sand agglomerate, which generally contains little cement for cost reasons, can detach over time due to strong temperature fluctuations, causing the slab to fall, especially if it has been used as lining.

[0005] The invention relates to the production of plates for the aforementioned uses by applying pressure, whereby the aforementioned disadvantages are eliminated or at least considerably reduced.

[0006] The invention has the particular objective of enabling the production of sheets which, during the known processes of pressing, drying, and surface grinding, are formed from two interconnected layers. These layers consist of a valuable conglomerate, which is intended to form the visible surface of the sheet, and an inexpensive conglomerate, which absorbs the excess water from the valuable layer during pressing and increases the thickness of the sheet during drying and grinding. The sheets can then each be divided into two sheets, each consisting entirely or substantially of the valuable and the inexpensive material, respectively.

[0007] The slab made of the valuable material can be produced in any thickness, even just a few millimeters. The product that is ultimately transported and used for covering floors and lining walls consists of a single layer of valuable material, the thickness and weight of which is much less than the pressed, dried, and sanded product.

[0008] The second slab, obtained by division and made of the inexpensive material, can be easily ground up, and the material thus obtained can be reused to produce layers for absorbing and reinforcing the other layers. If this layer has sufficient resistance and strength, for example, if a larger quantity of cement is added, it can be used for making ceilings, for laying terraces, and for less valuable and uneven floors, such as for sidewalks, basements, storage rooms, or the like. According to the main feature of the invention, this division of the slab with a large thickness, which is achieved by pressing the two layers, is made possible by inserting a thin layer of essentially water-permeable material between the two layers. A material that can be easily removed is incorporated. This material can consist of a mixture of cellulose fibers, particularly with paper or cardboard containing very little binder. To ensure that the two layers are sufficiently bonded and do not separate prematurely during processing, especially surface sanding, the paper or cardboard layer can be provided with appropriately distributed openings through which the two conglomerate mixtures bond. However, the openings occupy only a very small portion of the film's surface so as not to impede the separation of the sheet into two parts.

[0009] In the drawing, which shows an embodiment of the invention, Fig. 1 is a perspective view of a composite, pressed plate consisting of two thin layers, one of which has been partially removed to show the film separating the two layers, and Fig. 2 is a cross-section through the composite Plate of Fig. 1 before its separation into two layers of expensive and cheap conglomerate and Fig. 3 a cross-section through the separately shown components of plate of Fig. 2.

[0010] In the production of the slab by pressing, known means and devices are used, which are therefore not described here. These include a mold or an open-topped form in which the layers of the various conglomerates are arranged. The layer of the expensive conglomerate, which generally consists of marble chips or other expensive stone fragments and, if necessary, is bound by a small amount of marble powder, and also contains the necessary amount of cement to obtain a slab of great resistance and durability, is preferably placed first into the mold, resting on the bottom thereof. The manner in which the layers are placed into the mold, the composition of the layers, and the pressing process are not described here because these processes are part of the prior art.

[0011] Fig. 1 shows a layer 10 of a conglomerate containing the valuable stone. The surface 10' is subsequently carefully ground in a known manner to form the surface of a floor covering or a wall clad with the panels. Once the introduction of the mixture that is to form layer 10 is complete, a film 11 with openings 12, which, for example, have a diameter of a few millimeters and are evenly distributed, is placed on this layer. This film 11 can be made of highly absorbent and poorly adhesive paper, for example, coarse, inexpensive paper. The inexpensive conglomerate of a known mixture, which is required to form an absorption layer 13 for the excess water in the mixture for the production of layer 10, is then applied to this film 11.If a dense and resistant slab is desired, which is achieved by the hardening of layer 13, a larger quantity of cement than usual can be added to the mixture. It is known that the mixture of layer 13 is placed in the mold in an essentially dry state to ensure that the layer absorbs the excess water from the mixture of layer 10.

[0012] The pressing process is carried out in a known manner and with known means and is therefore not described.

[0013] At the end of this process, the product is obtained as shown in Fig. 2. It comprises an upper layer 10 with small-sized valuable rock, a lower layer 13 of an inexpensive mixture, and an intermediate film 11, wherein the two layers 10 and 13 are connected to each other at the bumps or small projections 12' that penetrate the openings 12 of the film 11, as shown in Figs. 1 and 3. These bumps 12', which establish the connection, all lie in the plane of the film 11, in which the mixtures are bonded to each other over small areas, thus allowing the layers 10 and 13 to be easily separated from each other.

[0014] After the material has completely dried and solidified, and after grinding the outer surface 10' of layer 10, the two layers 10 and 13 can be easily separated by means of a blade, for example a chisel, in direction A, as shown in Fig. 2. The film 11, which is saturated with water released by layer 10, offers very little mechanical resistance, just as the bumps 12' between the two layers 10 and 13 offer hardly any resistance.

[0015] The foil 11 therefore forms the split surface, which runs parallel to the large surfaces of the plate. Figure 3 shows how two separate plates are formed after separation, with the layer 10, which has the ground surface 10', being used for lining floors and walls or the like.

[0016] It is self-evident that, based on the invention, sheets of any thickness can be produced for lining. The thickness depends on the diameter of the compound layer, i.e., on the position the film occupies in the sheet produced by pressing. Similarly, the sheet can be designed with the thickness that is most advantageous for ensuring resistance during the various processing steps, since the overall diameter is determined by the sum of the diameters of layers 10 and 13, and there is no limit to the choice of the thickness of layer 13.

[0017] The layer 13 can be produced in the most favorable mixture and thickness for use without changing the thickness, weight, quality and characteristics of the layer 10 obtained by separating it from the layer 13.

[0018] Claims: 1. Method for producing slabs for coating floors, walls or the like, wherein the slabs are produced from a layer of a conglomerate of cement and valuable stone material, for example marble, by pressing in a mold a layer of a mixture of cement and valuable and small-sized stone material as well as an excess of water and a substantially dry layer consisting of sand or granular cheap natural material and a small amount of cement, so that a product is produced in which the excess water present in the mixture of one layer is absorbed by the second layer, wherein the first layer forms a surface of the slab which is ground in a known manner, characterized in thatthat a thin film (11), which is essentially water-permeable and easily removable, is inserted between a layer (10) of cement and valuable rock material and a layer (13) of a small amount of cement and predominantly inexpensive material; that, after the known processes of pressing, drying, and grinding the outer surface (10') of the layer (10), the two layers (10, 13) are separated by exploiting the ease of removal of the intervening film (11) to obtain a slab (10) having essentially a valuable composition and a ground surface (10'), the thickness of the slab being substantially less than that of the 1. Thickness of the pressed material with the three layers. 2. Method according to claim 1, characterized in that the thin removable film (11) consists of a mixture of cellulose fibers with a small amount of binders. 3. Method according to claim 1, characterized in that the thin removable film (11) consists of a sheet of heavy paper or cardboard that absorbs water well. 4. Method according to claims 1, 2 and 3, characterized in that the thin film (11) has openings (12) through which the two layers (10, 13) are directly bonded together, forming bumps or small projections (12') in the plane of the thin film (11) which are easily separable from one another when the layers are separated after the pressing, drying and sanding processes. 5.A method according to claims 1 to 4, characterized in that the separation of the two pressed and hardened layers is carried out by inserting a blade or wedge in direction (A) through the pressed product in the plane of the thin film (11). 6. A method according to claims 1 to 5, characterized in that the thin layer (13) contains sufficient cement to allow the composite, pressed sheet to separate after hardening. 7. The separation of the valuable layer (10) to obtain a continuous layer (13) that is usable on its own. 7. Method according to claims 1 to 5, characterized in that the cheap layer (13) is ground up after its separation from the valuable layer (10) in order to be reused as material for the production of new layers (13).