FR2598152A1 - Process and device for coating a thin article with a coating in sheet form and product obtained - Google Patents

Abstract

Process and device for coating a thin or similar article 1 with a coating in sheet form 4, the said article exhibiting at least one smooth prepared surface 2 intended to receive the said coating in sheet form 4 and a rough unprepared surface 3. According to the invention an antiadherent flexible mat 25 is provided between the support 5 and the article 1. Manufacture of panels for interior fixtures of aircraft.

Description

The present invention relates to a method for coating a thin piece or the like with a sheet coating, for example decorative. Although not exclusively, the invention is particularly suitable for coating a decorative sheet covering, the panel surfaces constituting the interior of the fuselage of aircraft.

The invention also relates to the devices intended to implement the method.

The invention also relates to products comprising such a thin part, at least one surface of which is coated with a decorative coating, obtained by implementing the method.

There is already known a method for coating a thin piece or the like with a sheet coating, for example decorative, said thin piece having at least one smooth prepared surface, intended to receive said sheet coating, and a rough unprepared surface, method according to which the thin part is placed by the unprepared surface on a support, then the sheet coating is deposited on said smooth surface, the face of which in contact with the part is coated with an inactivated adhesive film.

Then, the support is covered with a flexible membrane, intended to press, by the action of pressure means, said decorative sheet coating against the thin piece resting on the support.

The assembly thus pressed is subjected to a temperature and for a sufficient time for the adhesive film of the decorative sheet coating to be reactivated and for the said coating to be permanently bonded to the smooth surface of the part. After which, the assembly is cooled, then the pressure means are released. The flexible membrane is then removed and the part obtained, covered with the decorative coating, is removed.

This method is satisfactory, but nevertheless has drawbacks.

Thus, the unprepared surface (made for example of glass fibers or woven organic) of the thin piece resting on the rigid support (made for example of glass fibers and resin) has surface and shape defects such as cracks, streaks, ripples. These defects, when the decorative sheet coating is applied to the smooth prepared surface of the thin piece, are transferred during the pressing and heating stages, from the rough unprepared surface pressing on the support to the smooth prepared surface comprising said decorative coating. Indeed, the relatively high temperature, necessary to obtain the deformation of the decorative coating and to reactivate the adhesive film, causes softening of the resin of said thin part. As a result, the defects become apparent under said decorative coating.

Another disadvantage of the known method described above, appears when the edges of the part must be coated with the decorative coating.

Indeed, it is then stretched during the pressing and heating stages and extends beyond the peripheral contours of the part to be covered. The excess of this decorative coating is deposited on the tool by sticking to it, since the adhesive film has been reactivated. To overcome this drawback, it has been proposed to use a polytetrafluoroethylene film surrounding the contours of the part so that the excess of decorative coating is deposited, but does not adhere to this film. However, the installation of such a film is long, its cost is high and its lifespan is limited.

The object of the present invention is to remedy these drawbacks by avoiding in particular the rejecting of the parts, due to the surface defects appearing on the sheet coating.

To this end, according to the invention, the method for coating a thin piece or the like with a sheet coating, said piece having at least one smooth prepared surface, intended to receive said sheet coating and a rough unprepared surface, method according to which said piece is placed by the unprepared surface on a support, then said sheet coating is deposited on said smooth surface, the face of which in contact with said smooth surface of the thin piece is coated with an inactivated adhesive film, and the assembly is covered with a flexible membrane intended to press, by the action of pressure means, said sheet coating against the part resting on said support, then the assembly thus pressed is subjected to a temperature and for a duration sufficient for said adhesive film of said sheet coating to be reactivated and for said coating to be permanently bonded to the smooth surface of said part, after which the assembly is cooled, p uis releasing the pressure means to then remove the flexible membrane and remove the part obtained, coated with said sheet coating, is remarkable in that, prior to the step of laying said piece by the rough unprepared surface on said support , there is thereon a flexible non-stick mat whose dimensions are greater than those of said thin piece.

Thus, according to the invention, said mat on the one hand, absorbs the various surface and shape defects previously mentioned, without transferring them to the smooth surface of the thin piece receiving said sheet coating, and on the other hand, avoids by its dimensions greater than those of said piece, said adhesive film to deposit on the tool, while preventing said film from sticking to said carpet.

In a preferred embodiment, use is made of a mat formed from a first layer of flexible rubber and a second layer of silicone-based rubber, said first layer being disposed on said support, thus making it possible to absorb the surface defects, while said second layer receives the unprepared surface of the part, preventing the adhesive film, when it is reactivated, from sticking to the second layer.

Advantageously, the silicone babe rubber of the second layer can be in the form of a vulcanizing paste. Thus, the silicone-based rubber of the second layer is spread, using a first tool, on said first layer of flexible rubber, then it is leveled using a second tool, said second layer thus deposited. Before applying said second layer of silicone-based rubber, said surface of said first layer receiving said second layer is cleaned, using a degreasing product based on trichloroethane.

Preferably, when said thin piece and said sheet coating are porous, said support forms a face of a box, connected to a vacuum pump and, to press the flexible membrane and the decorative coating on the smooth surface of said piece, it is expected that the support is provided with a plurality of orifices. Thus, the volume inside the box is likely to be put in depression, so that the flexible membrane is deformed by suction thanks to the orifices made in the support and to the porosity of the part and of the coating, and plate said decorative coating against said part.

 Advantageously, according to the invention, to then allow a good distribution of the air flow under said part during the suction phase of the vacuum pump, it is applied to said layer of silicone rubber before hardening thereof. elements such as, for example, profiles, making, once these have been removed, imprints having a depth at least equal to the thickness of the layer of silicone rubber, after which, holes are drilled through the holes the layer of flexible rubber. The holes in the mat correspond to the holes in the support. Then sticking said flexible non-stick mat on said support.

 The invention also relates to ~ ies d .- "s, ts intended to implement the method of the invention.

For this purpose, the device for coating is thin or the like with a sheet coating, said pe'oe having at least one smooth prepared surface intended to receive said sheet coating and a rough unprepared surface, said device comprising a support. receiving said workpiece by the rough unprepared surface, a flexible membrane covering said sheet coating, the face of which in contact with the smooth surface of the workpiece is coated with an inactivated adhesive film, pressure means capable of pressing said membrane and said coating against said part, heating means acting upon actuation of said pressure means so that said pe; adhesive adhesive of said sheet coating is reactivated and that said coating is permanently bonded to the smooth surface of the part, is remarkable in that it comprises, in addition, a flexible non-stick mat placed on said support, and receiving said part , the dimensions of said mat being greater than those of said piece.

When said sheet coating and said part are porous, said support forms a face of a box connected to a vacuum pump, said support and said mat being pierced with a plurality of orifices allowing said flexible membrane during setting in action of said vacuum pump to be pressed by suction on said coating in porous sheet, which applies against the smooth surface of the porous part.

The invention also relates to thin parts or the like, a surface of which is coated with a sheet coating, produced in accordance with the method.

The figures of the appended drawing will make it clear how the invention can be implemented. Identical references designate similar elements.

Figure 1 illustrates the method according to the prior art by which a sheet coating is secured to a thin piece.

Figures 2 and 3 illustrate, on an enlarged scale, one of the drawbacks mentioned according to the method of the prior art.

Figures 4 and 5 show respectively in section and in perspective, an embodiment of said non-stick tapissouple used according to the method of the invention.

Figure 6 illustrates the method of the invention for securing a sheet coating of a thin piece.

The process for coating a thin piece or the like with a sheet covering, for example decorative, in accordance with the prior art and mentioned above is illustrated by FIGS. 1, 2 and 3.

There is shown, in FIG. 1, a thin porous part 1, having a smooth prepared surface 2 and a rough unprepared surface 3.

The part 1 is for example constituted by a central honeycomb structure, not metallic, coated on each side with a texture of glass fibers or woven organic fibers. After polymerization, the smooth surface 2 is free of defects since it is intended to receive the decorative coating in sheet #, and the unprepared surface 3 has a less careful appearance and a rougher feel.

The surface 3 of the part 1 is placed on a rigid support 5, made for example of glass fibers bonded with resin. The surface of the support 5 advantageously corresponds in shape to that of the unprepared surface 3 of the part 1. There is thus a satisfactory connection of the two surfaces.

A decorative porous sheet coating 4 is intended to cover the smooth surface 2 of the part 1. The face of the coating 4 in contact with the surface 2 comprises an inactivated adhesive film 6.

The support 5 is arranged in a set of decoration tools 7 partially shown, and forms a face of a box. The support 5 coated with said thin piece 1 and with the decorative sheet coating 4 can be covered by a membrane. flexible 1G mounted on a frame 11 intended to rest, with sealing, on the upper edge 13 of the box 8.

The pressure means used to press the decorative coating 4, via the membrane 10, on the smooth surface 2 of the part, require that the support 5 be provided with a plurality of orifices 16. In fact, a pump 12, intended to create a partial vacuum in the sealed volume 14 of the box 8 is connected to the bottom 15 of the box 8. The orifices 16 allow the free circulation of air in the volume 14. Thus, when the pump 12 is actuated placing the volume 14 under vacuum, the membrane 10 is sucked in through the holes 16 made in the support and the porosity of the thin piece 1 and of the sheet coating 4, and is applied against the thin piece 1 resting on the support 5 , completely matching the shape of said part. The assembly thus pressed is then subjected to heating provided by lamps 17 for example with infrared radiation, placed in the decoration tool 7, and this for a sufficient duration. when activating the adhesive film 6 of the decorative covering 4.

 The coating Lt therefore sticks to the smooth surface 2 of the thin part 1.

The assembly is then cooled under pressure.

After cooling and stopping the pump 12, the frame 11 holding the membrane 10 is removed and the part 1 dressed with the decorative sheet coating 4 is removed.

In a final step of the process, the excess coating Lt overflowing from the part 1 is cut.

As already mentioned in the preamble, to overcome the drawback due to the flow of part of the decorative coating Lt outside the outline of the part 1, a film of polytetrafloroethylene 19 has been placed surrounding said part. contour of the part 1, on the support 5, so that the excess of the coating 4 is deposited but does not adhere to said film 19.

There is shown in Figures 2 and 3 and on an enlarged scale, the main drawback of this method according to the prior art. The rough surface 3 of the thin part 1 has (FIG. 2) surface and shape defects 21, such as cracks, ridges, undulations. For the sake of clarity, the support 5, the thin piece 1, the sheet coating Lt, and the membrane 10 have been separated from each other. After the steps of applying pressure and raising the temperature of the process described above, the defects 21 are transferred to the smooth surface 2 of the thin part 1, due on the one hand to the small thickness of the latter and on the other hand to the softening of certain chemical compounds such as the resin, caused by the relatively high temperature intended to deform and soften the decorative coating 4 and above all, to reactivate the adhesive film 6.

Then, the defects 21 appear under the decorative sheet coating 4, and the parts leaving the tool cannot be used (FIG. 3).

The method according to the invention overcomes the drawbacks mentioned above. For this, to coat a thin piece or the like with a sheet coating, there is advantageously provided, on said support, a flexible non-stick mat 25, the dimensions of which are greater than those of the thin piece 1.

The part 1 is then placed by its rough unprepared surface 3 on the mat 25.

An embodiment of such a mat 25 is illustrated with reference to FIGS. Lt and 5. This consists of a first layer of flexible rubber 26 and a second layer of rubber, for example based on silicone. 27.

The layer 26 is arranged on the support 5 and the layer 27 is intended to receive the rough surface 3 of the part 1 (FIG. 6). Thus, the mat 25 on the one hand, absorbs by the flexible layer 26 the surface and / or shape imperfections and defects 21 previously mentioned without transferring them to the smooth surface 2 of the part 1 receiving the decorative sheet coating 4, and on the other hand, by the non-stick layer 27 7 prevents the adhesive film 6 of the coating 4 from sticking to the tool 7 when the pressure and heating means are put into action, since the dimensions of said layer non-stick 27 acting as protection opposite the tool 7, are greater than those of the deposited part. The dimensions of the mat 25 are substantially equal to those of the support 5. Therefore, the use of the film 19 used in the prior method is unnecessary.

The silicone-based rubber of the second layer 27 is in the form of a ready-to-use vulcanizing paste. This is spread over the first layer 26 using a tool such as a spatula, not shown, and is then leveled using a tool such as a rule 30 (shown in dotted in FIG. 4) resting on the edges 29 making it possible to respect a substantially uniform thickness of the layer obtained 27.

Prior to the laying of said paste; the face # of the first layer 26 intended to receive it is cleaned, by means of a degreasing product based on trichloroethane. The connection between the two layers 26 and 27 takes place without the addition of glue.

After having completed the leveling operation of the layer 27 of silicone rubber and before it hardens (for example, for a layer of approximately 1 millimeter thick, at 200C with a humidity level of 50 %, 4 to 5 hours are necessary to obtain complete hardening of the layer), it is advantageous to practice, for example, imprints allowing good circulation and distribution of the air under the thin piece 1 to be decorated during the aspiration of pump 12.

Before the hardening of the layer 27, we then apply, with a slight pressure, to the latter, profiles in U131 (FIG. 4) producing, once these have been removed, said imprints such as grooves 32 parallel to each other and having a depth substantially equal to the thickness of the second layer 27.

The width of the grooves 32 is of the order of 1 or 2 millimeters. After which, holes are pierced in said grooves 32, holes passing through the first layer 26 of flexible rubber, in correspondence with the holes 16 of the support 5.

The mat 25 obtained (FIG. 5) from the two layers 26 and 27 is then bonded to the support 5. In FIG. 6, this mat 25 is thus seen made up of the two layers in which the grooves 32 and the orifices 33 are formed. , allowing to have an excellent distribution of the air under the part 1 during the aspiration phase in the volume 14, as well as a correct placing of the part 1 on the support 5.

The flexible membrane 10 and the decorative coating of porous sheet Lt are then sucked up and are pressed against the smooth surface 2 of the porous thin piece 1. The method of the invention is then similar to what has been described above.

The drawbacks mentioned above are then eliminated.

The excess of the decorative coating Lt is deposited on the non-stick layer 27, thus avoiding sticking to the tool, and the surface defects and imperfections 21 are absorbed by the flexible rubber layer 26 and no longer appear on the smooth surface 2 and a fortiori on the decorative covering in sheet 4. One therefore obtains, after disassembly, a part 1 coated with the decorative covering Lt having a perfectly smooth external appearance.

 The invention also relates to the products obtained by the implementation of such a process. A particular application is the production of a decorative sheet coating on the thin panels constituting the interior of the fuselage of aircraft, but other applications, for example intended for the decoration of dwellings or upholstery of motor vehicles, are indeed heard possible.

Claims (10)

1 - Method for coating a thin piece or the like (1) with a sheet coating (4), said piece having at least one smooth prepared surface (2), intended to receive said sheet coating (lut) and a non-surface rough prepared (3), method according to which said part (1) is placed by the unprepared surface (2) on a support (5), then said sheet coating (lut) is deposited on the smooth prepared surface (2), the face of which in contact with the smooth surface of said thin piece is coated with an inactivated adhesive film (6) and the assembly is covered with a flexible membrane (10) intended to press, by the action of pressure means (12), said sheet coating (4) against the part (1) resting on said support (5), then the assembly thus pressed is subjected to a temperature and for a time sufficient for said adhesive film (6) of said sheet coating is reactivated and said coating is permanently bonded to the smooth surface (2) of said part (1), after which the assembly is cooled, then the pressure means (12) are released to then remove said flexible membrane and remove the part obtained coated with said sheet coating, characterized in that, prior to step consisting in placing said part (1) by the rough unprepared surface (3) on said support (5), there is thereon, a flexible non-stick mat (25) whose dimensions are greater than those of said thin piece. 2 - Method according to claim 1, characterized in that a mat (25) is used, made from a first layer of flexible rubber (26) and a second layer of silicone-based rubber (27), said first layer (26) of said mat being disposed on said support (5) while the second layer (27) receives the rough unprepared surface (3) of said piece (1). 3 - Method according to claim 2, characterized in that spreading, using a first tool, on said first layer (26) of flexible rubber, the silicone-based rubber of said second layer (27) which is in the form of a paste to be vulcanized, then leveling, using a second tool, said second layer (27) thus deposited. 4 - Method according to one of claims 2 or 3, characterized in that the surface of said first layer (26) receiving said second layer (27) is cleaned before applying # the latter, using '' a degreasing product based on trichîcréthane. 5 - Method according to one of claims 2 to Lt, characterized in that is applied to the second layer (27) of silicone-based rubber and before hardening thereof, elements (31) achieving, once these withdrawn, imprints (32) having a depth substantially equal to the thickness of said second layer, after which, holes are drilled in said imprints holes (33) passing through said first layer (26). 6 - Method according to one of claims 1 to 5, characterized in that said flexible non-stick mat (25) on said support. 7 - Device for coating a thin piece or the like (1) with a sheet coating (lut), said piece (1) having at least one smooth prepared surface (2) intended to receive said sheet coating (4) and a rough unprepared surface (3), said device ~ comprising a support (5) receiving said part (1) by the rough unprepared surface (3), a flexible membrane (10) covering said sheet coating (4) whose face in contact with the smooth surface (2) of the part (1) is coated with an inactivated adhesive film (6), pressure means (12) capable of pressing said membrane (10) and said coating (4) against said piece (1), heating means (17) acting upon the actuation of said pressure means (12) so that said adhesive film (6) of said sheet coating is reactivated and that said coating (lut) is permanently bonded on the smooth surface (2) of the part (1), characterized in that it further comprises a ta flexible non-stick udder (25) disposed on said support (5), and receiving said part (1), the dimensions of said mat being greater than those of said part. 8 - Device according to claim 7, characterized in that said mat (25) consists of a first layer of flexible rubber (26) disposed on said support (5) and a second layer of silicone-based rubber ( 27) receiving said part (1). 9 - Device according to one of claims 7 or 8, for securing a coating of porous sheet (4) on the smooth surface (2) of a thin porous part (1), characterized in that said support ( 5) forms a face of a box (8) connected to a vacuum pump (12), said support (5) and said mat (25) being pierced with a plurality of holes respectively (16 and 33), allowing to said flexible membrane (10), when actuating said vacuum pump (12), to be pressed against the said porous sheet coating (4) by suction, which it applies against the smooth surface (2) of the porous part (1).  10 - Product comprising a thin piece or the like (1) at least one surface of which is coated with a sheet coating (4), characterized in that it is obtained by implementing the process specified under any one of claims 1 to 6.