engobing process

Abstract

Engobing process The object of the invention relates to a process for coating a facing element for construction intended to be integrated and positioned against the surface of a construction, the facing element comprising at least two opposing surfaces, namely, on the one hand, an exposure surface intended to be oriented towards the outside of the construction and, on the other hand, a surface intended to be oriented towards the construction, characterized in that the process comprises: a surface homogenization step by an engobing operation projecting at least one clay composition onto at least the exposure surface of the facing element, a surface characterization step by a projection operation of at least one clay composition based on pigments according to at least one predefined distribution onto at least one engobed surface.

Description

Description Title of the invention: Engobing process The present invention relates to the field of production processes for construction surface elements and more particularly to the field of surface finishing processes for construction elements. In the construction of a building, the various building elements that contribute to its creation are intended to be located in specific positions defined according to the inherent properties of each element used. Thus, some building elements are designed to be placed at surface locations, for example, on a building's facade. Such building elements intended to be placed on a wall of a building present a visible face that contributes to the construction of that wall and therefore, at least in part, to the building's aesthetics. To meet aesthetic requirements, one solution involves selecting building elements based on the colors or textures of their raw surfaces, so that one of these surfaces can be positioned on a building's facade. Following this approach, some buildings are constructed with facades made from the surfaces of different bricks or terracotta tiles applied against the load-bearing structures. These bricks or tiles allow for the creation of a uniform color or, alternatively, variations in shade within a color range limited by the inherent hues of the materials, particularly terracotta, used to produce these bricks or tiles. To expand the range of surface finishes available for building facades and walls, the production of terracotta bricks and tiles has been enhanced by the application of a clay coating. This creates a unique, textured surface, independent of the building element's color, resulting in a finish derived from the coating. However, while this solution broadens the range of possible building element surfaces, it remains limited to the shades offered by clay materials. The present invention aims to overcome this drawback by proposing a solution that allows the production of building elements capable of meeting the expected structural constraints in the context of the construction of a building, while comprising at least one surface capable of presenting a finish, on the one hand, according to a wide range of colors and, on the other hand, according to a predefined pattern, or even according to a desired surface relief, in order to be able to meet architectural requirements. tonics. The invention thus relates to a method for covering a cladding element for construction intended to be integrated and / or positioned against the surface of a construction, the cladding element comprising at least two opposing surfaces, namely, on the one hand, an exposed surface intended to be oriented towards the outside of the construction and, on the other hand, a surface intended to be oriented towards the construction, characterized in that the method comprises: a surface homogenization step using an engobing operation projecting at least one clay composition onto at least the surface display of the facing element, a surface characterization step by a projection operation less a pigment-based composition according to at least one distribution predefined on at least one engobed surface. The invention also relates to an engobed and pigmented facing element, at least the exposed surface of which includes a coating obtained by a process according to the invention. The invention also relates to a device configured for the implementation of a process according to the invention. The invention will be better understood, from the following description, which relates to a preferred embodiment, given by way of non-limiting example. In this document, the term "facing element" should be understood as referring to an element intended to be positioned on a building surface so as to present a surface facing outwards. This outward-facing surface of the facing element, which features a particular pattern, thus contributes to the construction of part of the building's facade. The facing element may be formed, for example, by a brick intended to be at least partially integrated into the surface of a building, or by a tile or panel with a substantially flat arrangement intended to be positioned on at least part of the building's surface. Furthermore, this facing element may be manufactured in a form with a parallelepiped-like structure or something similar. It should be noted, by way of example, that prior to the coating process of the invention, the facing element is structurally produced, in particular, by an extrusion operation from a mixture of clays and sands and a drying operation. According to one embodiment, the mixture of clays and sands involves a selection step of the clays and sands that make up the composition of the mixture based on their respective pigments, so as to to achieve a desired color, This particular manufacturing method allows for the production of a facing element with color throughout its mass. The invention relates to a method of covering a cladding element for construction intended to be integrated and / or positioned against the surface of a building, the cladding element comprising at least two opposing surfaces, namely, on the one hand, an exposed surface intended to be oriented towards the outside of the building and, on the other hand, a surface intended to be oriented towards the building, characterized in that the method comprises: a surface homogenization step using an engobing operation projecting at least one clay composition onto at least the surface display of the facing element, a surface characterization step by a projection operation less a pigment-based composition according to at least one distribution predefined on at least one engobed surface. The engobing process during the surface homogenization stage involves projecting a clay composition onto the surface of the dried facing element. This clay composition ensures a homogeneous surface, thereby reducing or even eliminating any raised or uneven areas. Depending on the specific application method, the projected clay composition is selected based on its pigmentation to achieve a uniform color on the facing element. This uniform color, obtained at the end of the homogenization stage, serves as the base color for the surface of the facing element, which will then undergo a characterization stage. This engobing process also aims to project a clay composition designed to facilitate the surface characterization stage of the facing element, notably by creating a surface suitable for the fixation of pigments projected during this characterization stage. The projected clay composition is thus selected to incorporate at least one pigment or oxide intended to impart color to the composition, as well as silica or alkali frits designed to ensure mechanical adhesion of the composition to the surface mass of the facing element during a subsequent firing stage. The clay composition also includes at least one type of clay in addition to a solvent; this clay is intended to stabilize the suspension of the various components of the composition.It should be noted that this clay composition used as a slip on the facing surface allows for the creation of a suitable coating to optimize the hardness of the facing surface and its resistance to possible external mechanical aggressions such as scratches, for example sus- . likely to occur during the construction work or later during possible bad weather. The surface characterization step involving the projection of at least one pigment-based composition typically uses one or more ceramic inks. These ceramic inks, projected onto the clay slip, interact with the slip without dispersion. This is due to the slip's composition, which, on the one hand, homogenizes the surface of the facing element and, on the other hand, limits, if not neutralizes, the porous properties of the facing element's material that could otherwise cause the projected inks to disperse. Therefore, when the projected ink comes into contact with the clay slip, it remains positioned at its point of projection without dispersing into the surface material of the facing element.The use of a pigment-based composition allows for the creation of surfaces with a wide range of shades, tints and colors, without being dependent on the pigmentary limitations of the clay compositions used during the engobe application. In a specific example of how the coating process is implemented, the characterization step involves several different pigment-based compositions being successively applied to one or more of the coated surfaces. Thus, the pigment composition projection operation involves one or more inks being projected successively according to a specific and predefined distribution. This distribution may also be unique to each of the projected inks. According to a specific example of this particular implementation of the coating process, the characterization step of each of the pigment-based compositions is controlled by a control unit according to an actuation order and a predefined projection distribution. According to a specific example of this particular implementation of the coating process, the characterization step is carried out by at least one nozzle with a pivotable projection cone, controlled by a control unit. This characteristic of the projection nozzle allows for variations in the projection of one or more pigment-based inks onto an engobed surface in optimized orientations, and in such a way, in particular, that surfaces other than the exposed surface of the facing element can also be treated. According to another specific example of implementing the coating process, which may complement the example detailed previously, the homogenization and / or characterization steps are carried out on, firstly, the exposure surface and, secondly, the exposure surface and at least two additional surfaces forming at least part of the peripheral edge of the facing element. Thus, according to this specific example, the engobe application and the com- Pigment-based positions are applied to several faces of the facing element. According to a first specific feature of this example, the projection operations are carried out on three surfaces of the facing element, corresponding, on the one hand, to the exposure surface and, on the other hand, to surfaces positioned on either side of this exposure surface, each having a respective edge with the exposure surface. According to this first specific feature, the facing element obtained by such a process of the invention exhibits a coating that is visible on at least three faces of the element to an observer positioned opposite the exposure surface and at a plane perpendicular to and at the same height as the exposure surface of the facing element.According to a second specific feature of this example, the projection operations are carried out on at least five surfaces of the facing element which correspond, on the one hand, to the exposure surface and, on the other hand, to different surfaces positioned on the perimeter or periphery of this exposure surface, each of these surfaces having a respective edge with the exposure surface.According to this second characteristic, the cladding element obtained by such a process of the invention has an overlap that can be noticed on the different faces of the element visible to an observer positioned at different points on a plane opposite the exposure surface of the cladding element. According to a third characteristic of this example, the projection operations are carried out on at least six surfaces of the cladding element, corresponding to each of the element's surfaces, so that, in addition to the advantages offered by an element comprising five treated surfaces, such an element comprising all of its treated surfaces allows for simplified positioning on site. Indeed, it is then not necessary for the user to search for a single exposure surface to correctly position the cladding element on the structure. According to another particular example of implementation of the coating process and likely to be complementary to the examples previously detailed, the process also includes, after the characterization step, a step of highlighting at least one engobed and pigmented surface and / or a step of applying a protection to at least one engobed and pigmented surface. For example, the step of highlighting the engobed and pigmented surface involves a projection operation of a binder and a granular material, such as glass granules made from glass microbeads or oxides. These two projection operations can be carried out simultaneously or successively, so that the granular material adheres to the surface of the facing element under the effect of the binder. For example, the binder used for this operation is an adhesive or glue with sufficient viscosity to allow its projection.by a suitable nozzle. According to a preferred implementation example, the sprayed binder has a composition adapted to allow its projection in a fine and precise distribution onto the engobed and pigmented surface of the facing element, notably in the form of one or more dots of binder, so that determining the distribution of the binder on the engobed surface allows for anticipating the subsequent partitioning of the surface relief after the granular material has been sprayed. However, other shaping alternatives may be considered to allow the creation of an adherent surface capable of receiving and fixing a granular material. Thus, coating the engobed and pigmented surface with an adhesive is also a possibility.It should be noted that the relief obtained by the granular material makes it possible to create a significantly heterogeneous surface capable of compensating for, or even masking, the surface homogeneity obtained during the previous engobe application stage by projecting a clay composition. According to a preferred example of implementation, the projected granular material has a sufficient grain size to allow for a tactile sensation of relief on the surface, without this projected granular material obscuring the pattern of the pigment-based ink previously projected onto the engobed surface. According to one embodiment, the step of applying a protective coating to at least one engobed surface involves spraying a binder. This sprayed binder thus creates a protective layer on the surface obtained through the engobing and pigmenting operations. Furthermore, when the process includes a step of embossing by spraying a granular material, the subsequent spraying of a binder provides additional fixation of the granular material to the engobed and pigmented surface within the framework of the invention's process. According to a preferred embodiment, which is not intended to restrict the invention, the sprayed binder has a composition substantially similar to that of the binder used, so the spraying operation can be carried out in the same way.This additional protection provided by the binder on the engobed, pigmented and embossed surface of the facing element allows the facing element to be handled, up until it is fired, while limiting the risks of degradation of the treated surface(s). According to another specific example of the implementation of the covering process, which may complement the examples detailed previously, the process involves a step of moving the facing element using at least one moving device. This movement contributes, within the framework of the process implementation, to positioning the facing element at one or more stations adapted and / or configured for the implementation of one or more... several of the steps in the process of covering the invention. Such a means of displacement is likely to take the form of a conveyor belt. It should be noted that once the coating operations on one or more surfaces of a facing element are completed, the process continues with a firing stage that allows the various deposited organic components to burn off and the mineral components to fuse with the surface of the facing element. This is how the frits, pigments, and oxides fuse with the treated surfaces, while the organic compounds of the binders are burned off. The invention also relates to an engobed and pigmented facing element, at least the exposed surface of which includes a coating obtained by a process according to the invention. According to a particular embodiment, the facing element of the invention comprises a structure formed by a terracotta-type material. This terracotta-type material forms the support structure on which the engobing and pigment-based ink projection operations of the process are carried out. The invention also relates to a device configured for implementing a process according to the invention. According to one example of implementation, such a device can be integrated into industrial machinery and / or a production line for cladding elements. Of course, the invention is not limited to the embodiments described. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Demands

1. Method for covering a facing element for construction intended to be integrated and / or positioned against the surface of a construction, the facing element comprising at least two surfaces opposed, namely, on the one hand, an exhibition space intended to be oriented towards the outside of the building and, on the other hand, a surface intended to be oriented towards construction, characterized in that the The process includes: a surface homogenization step by an operation engobe projecting at least one clay composition onto at least the exposed surface area of ​​the facing element, a surface characterization step by an operation of projection of at least one pigment-based composition according to at least one predefined distribution on at least one engobed surface.

2. Method for covering a facing element according to claim- dication 1, characterized in that the homogenization and / or ca- Characterization is performed on, on the one hand, the exposure surface and, on the other hand, the exhibition area and at least two additional areas comments covering at least part of the peripheral edge of the facing element.

3. Method of covering a facing element according to one of the re- previous claims, characterized in that the process includes also, after the characterization stage, a highlighting stage of at least one engobed and pigmented surface and / or one application step of protection on at least one engobed and pigmented surface.

4. Method of coating a facing element according to one of the re- previous claims, characterized in that the characterization stage involves several compositions based on different pigments distributed successively on one or more of the coated surfaces.

5. Method of coating a facing element according to claim- dication 4, characterized in that the characterization step of each pigment-based compositions are controlled by a unit of control according to an actuation order and according to a distribution of predefined projection.

6. Method of covering a facing element according to one of the re- previous claims, characterized in that the characterization stage is implemented by at least one nozzle whose projection cone is pivotable and controlled by a control unit.

7. Method of covering a facing element according to one of the re- previous claims, characterized in that the process involves jointly a step of moving the facing element by at least one displacement mechanism.

8. Engobed and pigmented facing element, at least the surface exposure includes a coating obtained by a process according to one of the demands | at 7.

9. Facing element according to claim 8, characterized in that the facing element comprises a structure formed by a material of the terracotta type.

10. Device configured for carrying out a process according to one of the demands | at 7.