The present invention is related to the field of manufacturing processes of slabs, including structural slabs, of stone material.

As known, the rocks used in building for ornamental or construction purposes, are commercially classified in marble, granite, travertine or stone, depending on their origin, composition, minerals hardness and surface polishability; in the following description, all said rocks will be referred to as stone material.

The stone material is normally quarried in blocks, which, in turn, undergo further cuts by means of mono- or multi-wire machines, sawing machines, milling machines or other known types of machinery.

In order to obtain curved slabs of stone material, the processing method involves the use of special machinery, for example, the bridge saw with rotating head. The processes which involve the use of said types of machinery, however, present a series of drawbacks including, firstly, the high scrap that such a type of processing produces. In fact, the curved sawing of a curved slab from a block of stone material involves a considerable production of material waste. Furthermore, the high scrap also entails the necessity to be equipped with for its correct disposal.

A further drawback of the known processes for cutting slabs of stone material in a curved shape, can be identified in the long processing times which entail, as a direct consequence, an increase in the costs of the finished product.

The present invention aims to provide a process for making curved, but also flat, slabs of a stone material.

A further object is to provide a process for making curved slabs of stone material, which does not involve the production of material waste. A further object is to provide a process for making slabs of stone material of any shape, even complex, using as raw material, scraps of stone materials and/or split marble blocks which, due to their intrinsic characteristics, are not suitable to be processed.

Another object is to provide a processing method for marble or stone, which allows to obtain slabs of shapes which cannot be obtained through traditional processes.

Another object is to eliminate the scrap resulting from the milling or sawing process of the stone material, reducing the problems related to the waste disposal.

Another object of the present invention is to obtain reinforced slabs acting as load-bearing structure. Finally, a further object is to provide a structural slab of stone material with which it is possible to make arches, vaults, stairs, roofing, roofs or reinforcements, furnishing elements such as, for example, tables, desks and chairs, all said elements being able to sustain structural loads.

The aforementioned objects are achieved by the manufacturing method of slabs of stone material characterized by the steps of: - applying glue on a first slab of stone material;

applying a textile fiber canvas on said slab of stone material;

applying glue on said textile fiber canvas;

placing a second slab of stone material on said textile fiber canvas;

placing the manufactured item as obtained above in an airtight bag and removing the air from said bag, or in an autoclave of impregnation, to create a“vacuum”;

crushing the slabs of stone material;

positioning the airtight bag containing the crushed layers of stone material on a mold that duplicates the shape to be obtained;

injecting a glue into the vacuum bag; grinding the slabs of stones material until obtaining a smooth surface.

These and other purposes, as they will better appear in the description below, are achieved by the manufacturing method of slabs of stone material according to the present invention, which is described below, in a preferred embodiment with the help of the attached drawings which are non-limiting of further developments in the field of the patent itself:

Fig. 1, is a sectional view showing the elements forming the slab of stone material;

Fig. 2, is a sectional view showing the elements forming the slab of stone material within the vacuum bag;

Fig. 3, is a sectional view showing the slab of stone material following the crushing phase within the airtight bag;

Fig. 4, is a sectional view showing the crushed slab of stone material placed on the mold;

Fig. 5, is a sectional view showing the slab of stone material at the end of the manufacturing process.

With reference to the attached figures, the manufacturing method of the stone material slabs according to the present invention is described below.

Firstly, a sheet 5 in polymeric material of adequate thickness is placed on a supporting surface. Said sheet is made of a material that is, in any case, suitable for the subsequent vacuum creation stage.

A first slab of stone material 1 is placed on said sheet 5. The first slab of stone material 1 can be in any natural stone material, for example alabaster, granite, limestone, marble or onyx, but also cementitious material.

A layer of glue 2 is applied on said first slab 1. Said glue can be a thermosetting polymer, for example epoxy resin, cement, gypsum, plaster or lime. The glue 2 is applied on the entire surface of the slab 1.

A textile fiber canvas 3 is placed on said layer of glue 2. Said textile fiber canvas 3 may be Kevlar, basalt, glass fiber, carbon fiber, vegetal fiber or hybrid fiber. A further layer of glue 2 is applied on the textile fiber canvas 3 until covering the entire surface of the textile fiber canvas 3 and a second slab of stone material 4.

Depending on the needs and the required thickness, it is possible to apply a second textile fiber canvas on said second slab of stone material 4 and a third slab of stone material.

The aforementioned phases can be repeated in a similar way so obtaining a sandwich structure comprising several identical layers formed of slabs of stone material alternated with textile fiber canvas and glue. Through the present process it is also possible to use a number of layers greater than 3.

Once the above steps have been completed, the sheet 5 is folded and heat-sealed at the perimeter portions so as to obtain a bag entirely containing the above-mentioned layers. As an alternative, it is possible to directly use a bag of suitable dimensions and in which a vacuum state will be obtained by sucking in the air contained therein.

The set of stone layers, contained within said bag, undergoes a crushing step obtained through known means suitable for crushing slabs of stone material, such as presses or rollers.

The bag will be therefore suitable to be positioned on a mold 6. In fact, the slabs, being now constituted by scraps of small dimensions, can take any shape and therefore arrange themselves also on a curvilinear surface.

Once the bag has been placed on said mold 6, a glue is injected into said bag. The glue which may be injected inside the bag, can a polymer, such as an epoxy resin or a vinyl ester resin or, as an alternative, cement or gypsum can be used. During the resin injection process, the resin will evenly spread among all the layers and scraps of the sandwich thus obtained. The sandwich is then left on the mold 6 for a time necessary to the complete obtainment of the resin cross-linking process.

The slab is then extracted from the bag 5 and will have a shape corresponding to the shape of the mold 6 used. At the end of the cross-linking process, the scrap constitutes a single element, however, its surface, if curvilinear, will be uneven and jagged. Therefore, the surface undergoes a smoothing process until a smooth and uniform surface is obtained.

The slab, thus obtained, may also undergo a subsequent drying stage within a heated environment.

The slabs of stone material obtained through the manufacturing method according to the present invention can be used for decorative use, for example for the realization of sculptures, lighting elements, covering elements of curved wall structures.

The slabs can also be used as a load-bearing element for the construction of arches, vaults, stairs, roofing, roofs or reinforcements, or of furnishing elements such as, for example, tables, desks and chairs. Such a use is obtained thanks to the presence of fiber canvas interposed between the layers of stone material. The presence of said canvas guarantees a high level of resistance to cuts and to bending stresses of the structure thus obtained.

Finally, using stone materials such as basalt fiber or lava stone, the slab obtained through the present process will be highly resistant to combustion.