METHOD FOR PRODUCEING A COMPONENT BY MOLDING, MOLDING PLANT AND USE OF A FILM AT THIS END

Description

Scope of the invention

[0001] The present invention relates generally to the manufacture of molded parts. State of the art

[0002] There are many techniques for producing three-dimensional parts by filling an area or cavity in a mold with a liquid or viscous material and then allowing the material to set or harden.

[0003] These can be parts injected with a thermoplastic or thermosetting material, resin infusion in a mold where structural elements have been incorporated (including mineral fibers such as glass fabrics, etc.), molded concrete elements, etc.

[0004] Document FR2124363A1 also gives another example of a process where a reinforcing material is inserted into a gel applied to the mold, this "crust" being combined with a core made of an expandable foam.

[0005] As a general rule, when it is necessary to give such parts a particular surface appearance and / or particular surface properties, one starts by making the mold, then the raw part is extracted from the mold and treated (sanding, coating, painting, etc.) to give it the desired appearance.

[0006] The present invention aims to simplify operations when such a part needs to have a particular external appearance, and / or a particular external property.

[0007] It should be noted that here we mean "external appearance" or "external property" the presence of any application of one or more layers for purposes including decoration, protection, improvement of surface properties, improvement of mechanical resistance, functionalization of the surface, etc. Summary of the invention

[0008] It was unexpectedly observed that a pre-existing film comprising a dry layer of a paint-like material anchored in a particulate file could behave very stably when interposed between the mold and the part being formed, despite the significant stresses (mechanical, possibly thermal, etc.) involved in molding processes in general.

[0009] To this end, a manufacturing process for a part as defined in claim 1 is proposed.

[0010] Preferred but not limiting aspects of this process include the additional features defined in claims 2 to 10.

[0011] A second aspect is proposed: an installation for manufacturing a part with a molding material as defined in claim 11.

[0012] Preferred but not limiting aspects of this installation include the additional features defined in claims 12 to 15. Brief description of the drawings

[0013] Other aspects, objects, and advantages of the present invention will become more apparent upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example and with reference to the accompanying drawings, in which: there Fig. 1 is a schematic vertical cross-sectional view of an installation for manufacturing a part by a process known as infusion according to the invention, the Fig. 1A is an enlarged cross-sectional view of an element used in the process of the Figure 1 , there Fig. 2 is a partial, enlarged cross-sectional view of a part produced using this process Fig. 3 is a cross-sectional view of the part after peripheral cutting, the Fig. 4Ais a cross-sectional view with exaggerated thickness of a transition region between two elements of the type of the Figure 1A according to a first approach, the Fig. 4B is a cross-sectional view with exaggerated thickness of a transition region between two elements of the type of the Figure 1A according to a second approach, the Fig. 4C is a cross-sectional view with exaggerated thickness of a transition region between two elements of the type of the Figure 1A according to a third approach, the Fig. 5 is a schematic vertical cross-sectional view of another method for manufacturing a part according to the invention, the Fig. 6 is a schematic vertical cross-sectional view of the part thus produced, the Figs. 7A to 7C illustrate in cross-section another method of manufacturing a part according to the invention, and the Fig. 8 illustrates the finished part in cross-section. Detailed description Generalities

[0014] We will now describe methods for producing three-dimensional parts incorporating an integrated coating according to the invention.

[0015] There Figure 1 schematically illustrates in cross-section an installation for the production of a part using an infusion-type technique.

[0016] It is recalled that this technique consists, in a manner known per se, of making a mold 100 for the part, of placing along the internal surface of the mold (mold bottom, the shape of which is chosen according to the part to be made), in a region called the molding zone, one or more layers of a reinforcing and / or stiffening material 300, such as superimposed sheets of a fabric such as a glass fabric, carbon fabric, etc., then of arranging above this assembly a sealed sheet 400 called a "vacuum-bag" to which are associated arrangements for the arrival of a resin, namely a resin reservoir 110, one or more resin supply lines 111 and one or more devices 112 for sealed connection between the line(s) 111 and the internal space defined between the sealed sheet 400 and the mold 100. The installation also includes an arrangement for creating a vacuum in the internal space in question.This arrangement includes a vacuum pump 120, one or more vacuum lines 121, and one or more leak-proof connection devices 122 between these lines and the interior space. As illustrated in the figure. Figure 1 , one or more drainage layers 310 are also advantageously provided, generally thicker and more open than the reinforcing material, intended in a way known per se to facilitate the circulation of the resin to all areas of the part during the infusion process.

[0017] The vacuum system is complemented by peripheral sealing elements, such as a thick, highly deformable 130 adhesive gasket, ensuring a watertight connection to the periphery of the 400 sealing sheet. This gasket can also be used to create seals at the resin inlet and vacuum application points. As an alternative or supplement to the thick adhesive gasket, an adhesive strip can be used, for example.

[0018] Advantageously, the vacuum is applied to the interior space in one or more locations distant from the locations where the resin is brought.

[0019] In this known process, the application of a vacuum in the interior space causes infusion, namely the regular and progressive migration of the resin over the extent of the part from the supply region(s), the resin impregnating the reinforcing material 300 and coming to apply intimately against the upper surface of the mold until it fully includes the reinforcing material and completely covers the upper surface of the mold 100.

[0020] In such a process, the thickness of the part produced is determined mainly by the composition and arrangement of the reinforcing material, and in particular by the thickness of the layer and the number of plies in the case of a stack of glass weaves, and where applicable by the drain(s) provided.

[0021] Once this infusion has been completed and after the resin has fully set, the 400 sealing sheet and the various sealing, resin supply and vacuum application fittings are removed and the part is separated from the mold.

[0022] This part includes 300 reinforcement material embedded in resin. The underside of the part has a surface finish that is the negative of the surface finish of the upper surface of the mold, which is generally smooth.

[0023] The upper surface of the piece has a raw appearance and its regularity depends on the different factors of resin propagation during the infusion process.

[0024] In general, the underside of the piece is its visible side, while often its upper side will not be visible (as in the case of a boat hull among many examples).

[0025] When you want to give the underside of the part a particular appearance, you apply a liquid or gel product, typically paint, gelcoat, etc., to that side using a roller, brush, spray gun, etc.

[0026] According to one inventive aspect, it is planned here to place against the upper surface 101 of the mold 100, during the preparation of the installation before infusion, a paint film 200 intended to cover the lower face of the part (which will generally be its external, exposed or visible face) after infusion.

[0027] This sheet is created, for example, in accordance with the teachings of document WO2016110799A1 on behalf of the applicant. As illustrated on the Figure 2, this sheet 200 includes a layer of a paint-like material 201 anchored in a fibrous backing 202. Herein, "paint-like material" means an opaque (pigmented) or transparent or translucent (varnish) material that is normally applied in liquid or gel form, as opposed in particular to thin films of plastic material, single-layer or laminated.

[0028] The type of paint and the type of fibrous backing can be chosen from a wide range, depending on the desired application (see below).

[0029] The film 200 is positioned against the mold so that the paint layer 201 is on the mold side, and the fibrous backing 202 is on the upper side. If necessary, an adhesive agent with a controlled coefficient of adhesion, such as a PSA (Pressure Sensitive Adhesive), is placed between the film 200 and the mold 100 to prevent any movement of the film 200 during the infusion process, to ensure close contact between the film 200 and the mold base, and to prevent any resin leakage into any gaps that might exist between the film 200 and the mold 100. This agent is chosen so that after the part has been manufactured, it can be removed without leaving any residue.

[0030] Alternatively, the 200 sheet can be manufactured with an outer layer (paint side) of peelable film onto which an adhesive film is applied before being placed in the mold. In this case, the adhesive and peelable film assembly separates from the product when the part is removed from the mold. The mold is then cleaned of this residue.

[0031] With the presence of the 200 sheet, during the injection process, the resin brought into the interior space spreads progressively within it under the effect of the application of the vacuum, and in particular comes to be interposed between the layers of the reinforcing material 300 and the 200 sheet, becoming intimately anchored in the fibrous backing 202 of the latter.

[0032] At the end of the process (after removal of the 400 sealing sheet but before detachment from the mold) and after the resin has hardened, a part is obtained as illustrated in the Figure 2It is observed that the fibrous backing 202 of the sheet 200 achieves an extremely robust bond between the infused resin 500 and the paint layer 201. Advantageously, the structure and density of the fibrous backing 202 and the viscosity of the resin 500 before hardening are such that, during infusion, the resin penetrates the structure of the fibrous backing 202 until it reaches the limit of the paint layer 201 within the backing.

[0033] Once the process is complete, the resin has hardened, and the part is removed from the mold 100, the product can undergo peripheral trimming to eliminate areas lacking the reinforcing material 300. More generally, depending on the nature of the part, various trimming and finishing steps may be considered. The final part is illustrated in the Figure 3 .

[0034] The final result is a part with a very well-bonded layer of 201 paint on its mold-side face (generally its visible face). This layer can serve various functions: decoration, protection, and also functionalization of the part's surface through the integration of specific layers into the paint layer(s), as described, for example, in the various patents published in the Applicant's name. Use of multiple strips

[0035] When the size of the part to be manufactured is such that two or more sheets of 200 film must be placed side by side, it is necessary to take precautions to prevent the resin from overflowing outside the paint layer 201 into the gap that naturally exists between the two sheets during the infusion process. Various approaches can be considered to avoid this problem.

[0036] In a first approach and with reference to the Figure 4A Two strips, 200a and 200b, are simply placed edge-to-edge. In particular, if the 200 sheet is held against the mold 100 by an adhesive, this may be sufficient to prevent resin migration between the mold and the sheet through the gap between the two edge-to-edge strips. Alternatively, an adhesive can be applied locally to the mold at the joint between the strips; this adhesive is removed after demolding.

[0037] According to one variant and now referring to the Figure 4BThe areas of the strips adjacent to their opposite edges are treated before the infusion operation, for example by spraying a 204 type hot-melt adhesive or by coating with a resin, or by applying an overlapping adhesive strip, so as to create, overlapping the two strips, a barrier to the migration of the resin outwards during the infusion.

[0038] In this case, the applied product 204 is chosen to ensure a strong adhesion interface with the resin used for infusion.

[0039] In a third approach and with reference to the Figure 4CThe strips 200a and 200b are placed in overlap, which inherently prevents the resin from migrating towards the interface between the mold and the film. However, a suitable adhesive 205 can optionally be interposed between the strips at their overlap, and / or an overlapping adhesive can be applied between the strips as in the case of the Figure 4B . Resin propagation

[0040] The infusion conditions are chosen so that the resin spreads as uniformly as possible in the space defined between the sheet 200 and the waterproof sheet 400, progressively impregnating the reinforcing material 300. In the case where one or more drains are provided, these facilitate the progression of the resin in a way compatible with its setting time.

[0041] Furthermore, as is known to those skilled in the art, it is possible to multiply the resin supply points and / or the vacuum application points in the internal space, and to use other means such as cannulas, infusion ramps, etc. Conformity

[0042] In the case where the shape of the mold bottom against which the sheet 200 is applied is not developable, it is necessary that the sheet 200 be able to undergo plastic and / or elastic deformations allowing it to adapt intimately to the shape of the mold bottom.

[0043] For this purpose, the film can be made partly with a paint-type material 201 that allows it to be stretched, or even compressed, within its plane, and partly with a backing 202 that permits such movement. For example, polyurethane or polyurethane elastomer paints, etc., can be used.

[0044] In addition, to ensure this deformability, the backing can be made of compact particles or short fibers generally not intertwined, for example of glass or glass and cellulose, or of a mesh or knitted with stretchable meshes giving a possibility of stretching in all directions. Materials and parameters

[0045] We will now give a number of examples of materials and parameters that can be used in an infusion process as described above. Infused resin type: two-component resins such as epoxy resins, polyester, vinyl ester, polyurethane, possibly bio-based, or thermoplastic or thermosetting synthetic materials; Reinforcement material type 300: in sheet or layer: fabrics (taffeta, satin, twill, mesh, knitted, etc.), non-woven, particulate: glass fibers or grains, carbon, aramid, Kevlar ®, linen, with weights of around 20 to 600 g / m2, type of film paint 200 and range of thicknesses: two-component (epoxy or polyurethane) or one-component (acrylic, epoxy, polyurethane); thickness of around 30 to 120 µm; it should be noted here that in the case where the infusion process involves heating, or in the case where the setting of the resin generates heat, the nature of the paint and, where applicable, its fibrous backing are chosen); type of fibrous backing for sheet 200, density and thickness: glass or glass-cellulose fabric or mat, with a basis weight of approximately 15 to 150 g / m2, type of adhesive for retaining sheet 200 against mold 100: PSA type adhesive (“Pressure Sensitive Adhesive”), acrylic, hotmelt rubber, with a dosage of approximately 5 to 50 g / m2, chosen to induce limited adhesion forces not hindering the demolding of the part. Other forms of implementation

[0046] Now referring to the Figure 5 , a decorated solid building element is made by manufacturing a 100' mold of which one or more faces receive a 200' sheet for example made in accordance with document WO2016110799A1, the intimate contact between the wall of the mold and the sheet (paint side) being ensured here again with the help of a PSA type releaseable adhesive or by designing the 200' sheet with a peelable varnish which is then glued, as described above.

[0047] A hardenable material 500' such as cement or concrete is then poured into the mold so that the material impregnates the 202' file of each 200' sheet bearing the 201' paint, until it comes into contact with the latter.

[0048] After setting or hardening, the result is a piece with one or more faces bearing a decorative layer formed by the foil firmly anchored in the material, as illustrated in the Figure 6 .

[0049] The same technique can be used to obtain other products, for example, based on concrete or plaster (plates, tiles, blocks, etc. with at least one molded face).

[0050] The invention can also be implemented in a thermoplastic or thermosetting material injection process. In both cases, the choice of material for layer 201 is made according to the temperatures to which it will be exposed, either at the time of feeding a thermoplastic material, or at the time of heat treatment of a thermosetting material.

[0051] According to yet another form of realization, and with reference to Figures 7A-7C and 8 , the process as described with reference to Figures 1 to 4is modified so that the placement of the 200 sheet is not carried out at the bottom of the mold before the implementation of the actual molding process, but by forming an assembly consisting of a preform of molding material on the one hand and a 200 sheet applied against this preform and at least partially anchored in it on the other.

[0052] For this purpose, a preform 600 is produced on a first mold 700, for example, using an infusion or pre-impregnation process on a reinforcing material such as a series of fiberglass layers. The mold 700 is, for example, flat or has a slight curvature. This preform can be pre-compacted, for example, by applying a vacuum, in a conventional manner.

[0053] As illustrated in the enlarged section on the right of the Fig. 7A, the preform 600 also includes in its lower part a sheet 200 for example of the type described above, which has been previously placed against the upper face of the mold 700 so as to anchor itself in the preform of the preform 600 during the formation of the latter.

[0054] The preform 600 fitted with the sheet 200 is then placed between a mold 100 and a counter-mold 100' ( Fig. 7B ), equipped with facing mold faces 101, 101' respectively, these being brought together to give the preform 600 its final shape ( Fig. 7C ) and obtain a part having on its underside the 201 paint layer of the sheet.

[0055] If necessary, part 600 is heated to a suitable temperature to make it malleable enough to undergo the required deformation. The molding material is typically a thermoplastic resin in this case.

[0056] Alternatively, particularly when using a polymerizable resin, the following operations are performed: Figs. 7B and 7C at a stage of partial polymerization where the preform remains conformable.

[0057] The completed part P is illustrated on the Fig. 8 .

[0058] According to an unillustrated variant, the preform 600 can be made on the first mold 700 without planning at this stage of sheet 200, and the sheet can be brought onto the bare preform with pressure (calendering or other), if necessary with the addition of adhesive or by heating the bare preform. General remarks

[0059] It should be noted that, regardless of the embodiment, the nature and thickness of the fibrous backing of the sheet are chosen to suit the nature and viscosity of the curable material. In particular, the texture, density, and thickness of the free portion of the backing 202 of the sheet 200 can be chosen based on factors such as the viscosity and other properties of the filler material when it comes into contact with the sheet, ensuring that the material properly fills this free portion and provides effective anchoring. For example, a more porous texture is required for a more viscous material, and a greater thickness for a material that is friable after setting or hardening, etc. Furthermore, it is observed that in most cases, the backing 202 contributes to the mechanical reinforcement of the finished part at the surface receiving the sheet.

[0060] Furthermore, in some cases it may be advantageous to use a microporous paint with open pores to allow air that may remain trapped in the free part of the fibrous backing to escape.

[0061] Finally, any suitable reinforcing or filler material can be provided, depending on the application, in an elongated shape with short or long fibers or, on the contrary, in a compact shape.

[0062] Of course, the present invention is by no means limited to the embodiments described and illustrated in the drawings, but a person skilled in the art will be able to make many variations or modifications to it and will be able to apply it to many other fields, in particular to pre-impregnation processes ("pre-preg"), contact molding, resin transfer molding (RTM for "Resin Transfer Molding", etc. The present invention is defined by the attached claims.

Claims

1. Method for manufacturing a component, comprising the following steps: (a) providing a mould (100) which defines a moulding area, at least one wall (101) of which is intended to define a finished surface of the component, (b) providing a film (200) prepared in advance and comprising a dry layer (201) of a paint-type material entrenched in a particulate backing (202), the paint-type material being intended to be in contact with said wall and the particulate backing intended to be turned towards the moulding area, (b') arranging the film (200) against said wall (101) of the mould, (c) filling the moulding area with a viscous moulding material (500) capable of hardening, under conditions whereby said particulate backing of the film and the moulding material interpenetrate, by penetration of the moulding material into the structure of the particulate backing, such that the film (200) is firmly pressed against the mould and both the moulding material and the film conform to the shape of the mould wall, (d) causing the moulding material to harden, and (e) removing the item from the mould.

2. Method according to claim 1, characterised in that it also comprises a step of placing a reinforcement material (300), which is intended to be embedded in the moulding material, in the moulding area prior to filling.

3. Method according to any one of claims 1 and 2, characterised in that it comprises a step of interposing a means for holding the film in position between the mould wall and the film.

4. Method according to any one of claims 2 and 3, characterised in that the moulding material (500) is resin-based.

5. Method according to any one of claims 2 to 4, characterised in that the moulding material (500) capable of hardening is supplied via a process selected from the following group: infusion, pre-impregnation, contact moulding, resin transfer moulding, or pouring.

6. Method according to claim 1, characterised in that it comprises, between steps (b) and (c), a step of applying the film against a deformable preform of the moulding material, in such a way that there is at least a first degree of interpenetration between said particle material of the film and said moulding material, and that the assembly maintains physical integrity, and a step of pressing the assembly against the wall (101) of the mould (100) so that it takes on the final shape of the item as defined by said wall.

7. Method according to claim 6, characterised by the fact that it also comprises a step of producing the preform by impregnating a reinforcement material (300) with the moulding material.

8. Method according to claim 7, characterised in that the preform is produced using an initial mould (600) on which the said film (200) has been positioned.

9. Method according to any one of claims 1 to 8, characterised in that the particulate backing (202) of the sheet is a fibrous backing selected from a group comprising nonwovens, wovens, meshes, and knits.

10. Method according to any one of claims 1 to 9, characterised in that the particulate backing (202) of the film is a backing consists of essentially non-intertwined or knitted particles, allowing it to be stretchable in at least one direction, and in that the paint-type material (201) is also stretchable.

11. Installation for the production of a component using a viscous moulding material capable of hardening (500), particularly resin-based, characterised by the fact that it comprises: - a mould (100) defining a moulding area, at least one wall (101) of which is intended to define a finished surface of the component, and a film (200) prepared in advance and comprising a dry layer (201) of a paint-type material entrenched in a particulate backing (202), the paint-type material being maintained in contact with a wall (101) of the mould, and the particulate backing being oriented towards the moulding area, such that the moulding material can penetrate into the structure of said backing during the moulding process.

12. Installation according to claim 11, characterised in that it also comprises a reinforcement material (300) placed in the moulding area and intended to be embedded in the moulding material (500).

13. Installation according to any one of claims 11 and 12, characterised by the inclusion of a means for holding the film in position, interposed between the mould wall and the film.

14. Installation according to any one of claims 11 to 13, characterised in that it comprises a device for supplying the moulding material capable of hardening using a process selected from the following group: infusion, pre-impregnation, contact moulding or resin transfer moulding, or a device for supplying the moulding material capable of hardening by pouring.

15. Installation according to one of claims 11 to 14, characterised in that the particulate backing (202) of the film consists of particles that are essentially non-intertwined or knitted, allowing it to be stretchable in at least one direction, and in that the paint-type material (201) is also stretchable.