Coating for visible parts

Abstract

A method for manufacturing a body panel for a structure, comprising a step of assembling a thermoplastic structure to the back of an outer surface layer. The layer (20) is pre-formed by pressing (E3) between two heated platens (E2) of a thermoplastic compound (10). The part is an interior or exterior component of the vehicle. Abbreviated figure: 1

Description

Title of the invention: Coating for visible parts

[0001] The invention relates, in various sectors of application, to the visible parts of objects of various kinds to which it is desired to give an attractive appearance, to enhance the object or attract attention. The invention applies in particular to vehicles, in particular motor vehicles, whether for the interior parts, in the passenger compartment, or their elements visible on the outside. The invention also applies in commercial contexts with product displays, stands, easels, advertising placards of the POS type (advertising at the point of sale), bottles and packaging. These parts have an aesthetic role, by which they dress and therefore enhance the objects for customers or users, by their attractive appearance.Their surface can traditionally be matte or shiny, painted, or defined by a coating, such as a woven or non-woven textile, a synthetic sheet or leather, but the invention brings, in a break with these solutions, new original and enhancing methods to the appearance of these pieces.

[0002] In the automotive field, we are interested in interior parts - and therefore interior parts of the vehicle concerned, which in this case is often a car, or even a truck or another land vehicle or not. The interior part can be a dashboard, a central console or a door trim, in which case we are looking for a comfort effect for the passengers. We are also interested in exterior parts, such as bodywork elements or exterior decorative inserts, or door protections, in which case the surface of the part must be adapted to the exterior conditions, which include bad weather.

[0003] Commonly, these parts can be formed from injection-molded plastic, the material forming the body of the part being chosen from the family of thermoplastics such as the very commonly used polypropylene (PP), or in various applications, polycarbonate (PC), acrylonitrile butadiene styrene (ABS) or even polyamide (PA) or polyethylene (PE), and therefore constituting a petroleum derivative. For a long time, a new and homogeneous (virgin) polymer was used, which gives a uniform appearance to the surface which is visible.

[0004] The polymer also contains a pigment, diluted homogeneously. Different pigments exist, which makes it possible to make parts of different colors, clearly differentiated. The product is obtained from a supplier, initially often in the form of granules, which are small, approximately spherical volumes - often produced by extrusion and cutting - and it is melted and coagulated by heating in an injection mold. It retains a homogeneous appearance during shaping, giving the part a new appearance.

[0005] Nevertheless, in the context of an economy and material constraints which are such that raw materials are more scarce and must be recycled, what is called the circular economy, it is increasingly practiced to construct the structure of the part on the basis of a composite structure including natural fibers or by using recovered plastics, for example elements recovered during the dismantling of a vehicle at the end of its life. These are two different solutions, possibly combinable, the implementation of which is dictated by the circumstances surrounding the product to be manufactured, and the availability and cost of raw materials.

[0006] But it is also interesting to seek to use unused materials from various sources, such as unrecovered offcuts in an industrial process using virgin resin, of different colors, or end-of-production elements, or from scrap, or mass production waste.

[0007] Unfortunately, using such a recovered raw material to mold the body of a part in an injection mold commonly gives a result that is not very visually appealing: the part generally has traces of material flow called "tiger stripes", problems with re-bonding the material, or appearance defects due to the non-homogeneity of the material resulting from the recovery. It is also difficult to achieve high repeatability from all points of view within a series production. In a traditional injection process, it is indeed difficult to obtain a repeatable appearance with recovered raw material. The material flow lines are in fact drawn randomly, and they are visible. It is not possible to obtain a speckled effect, which would conversely be more attractive.There is therefore little interest in using this raw material from recovery with a process similar to the prior art.

[0008] Nevertheless, we know of eco-responsible materials that can be used to form the body of a part, without necessarily being perfectly adapted visually, such as thermoplastic composite plates with natural fibers, or even recycled polymer granules, which are nevertheless not very available on the raw materials market.

[0009] To solve this problem of optimized material recovery, and therefore provide eco-responsible and attractive products, parts incorporating recovered materials and with an improved appearance are proposed here, for the automotive industry and other application sectors, such as point-of-sale advertising, packaging or bottling. These are optimized to minimize the consumption of petroleum products, and to highlight, to the user, the use of recycled material, in an attractive and favorable manner.

[0010] Furthermore, a product is provided in which only one type of synthetic material, or a limited number of types of synthetic materials, is ultimately present, which allows these materials to be recycled at the end of their life, since there is no need to separate too many materials.

[0011] Thus, a method of manufacturing a piece of clothing for a structure is proposed below, comprising a step of assembling a thermoplastic structure to the rear of an external appearance layer.

[0012] These are known principles which have the advantage of simplicity: the structure, being hidden by the appearance layer, can have any visual appearance, but be selected to optimize its excellent mechanical properties obtained by well-known, controlled and inexpensive methods, due to its thermoplastic nature which allows it to be shaped by conventional techniques and if necessary with the necessary reinforcements. In addition, this can be obtained with eco-responsible materials. But this technical part remains hidden, since the appearance is obtained by the use of an external appearance layer which can be manufactured independently, and which by its nature of layer, is economical in material, light and has little influence on the mechanical properties of the whole. And the presence of this layer makes it possible to hide the appearance which can be unattractive of the structure.

[0013] Due to its mechanical properties, which reflect those of the thermoplastic structure placed at the rear, the final product itself constitutes a structure with an improved appearance.

[0014] Different techniques for assembling a thermoplastic structure on a layer of material exist, in particular overmolding (performing a molding on an already finished product, by injecting plastic onto a metal, plastic or ceramic insert in particular), or thermocompression or compression molding (placing a volume of the material in an initially open mold, which is heated then pressed by closing the mold).

[0015] Remarkably, according to the invention, the outer appearance layer is formed beforehand by pressing, between two horizontal heating plates, a thermoplastic mixture comprising pieces of recovered thermoplastic parts crushed and dispersed on the lower plate.

[0016] This is very original, and offers a great possibility of various achievements, while defining a simple and effective process. This principle makes it possible to obtain an original speckled effect with different colors, never obtained before, very decorative.

[0017] The heterogeneous thermoplastic mixture may comprise several juxtaposed colors, due to the inclusion of recovered parts from different sources and therefore often of different colors, which defines its heterogeneity. It may also comprise virgin polymer, in addition to the recovered parts, forming an additional color. The whole is ground into granules before being dispersed on the lower tray. There are at least two different colors. Thus the mixture is vis It is generally heterogeneous and includes several juxtaposed colors, through the inclusion of pieces of salvaged parts of different colors. Thus, the heterogeneity is found in the layer, which highlights the different colors next to each other, not drowned in each other and therefore visible separately.

[0018] The invention can also be implemented with inclusions of materials of various natures. Thus, the heterogeneity is found in the layer, which highlights the inclusions of added materials, which are visible on the surface of the layer. This results from the fact that it has been prepared by the process, between the two heating plates, which are pressed against each other to produce a continuous layer of uniform thickness, and of surface which can be smooth and in any case regular. Thus, the mixture is visually heterogeneous and it includes pieces of textile, pieces of reed, pieces of cork, pieces of leather, pieces of shells, visible, mixed with the pieces of thermoplastic part.

[0019] And the fact that this was done before (prior to) assembly provides fine control over the manufacture of the layer.

[0020] Finally, the appearance is quite variable from one copy to another, due to the random nature induced by the heterogeneity of the mixture. Different colors from the different recovered plastic pieces used initially are visible on the surface, in addition to a possible addition of virgin plastic and / or different inclusions, such as textile, reed, leather, shells, cork, appearing randomly.

[0021] As for the structural part, it is preferably formed with eco-responsible materials, such as composites incorporating natural fibers or quality materials co-produced secondarily by an industrial process.

[0022] According to advantageous and optional characteristics,

[0023] - the mixture is visually heterogeneous and it includes in the granules different colors and inclusions of non-plastic material;

[0024] - the assembly may be a thermocompression of the outer appearance layer with a structural thermoplastic layer; - the structural thermoplastic layer can then be a layer of a polypropylene matrix reinforced with natural fibers, or a layer of non-woven polyester (PES) and polypropylene fibers;

[0025] - the assembly may be an overmolding of an injection of thermoplastic material; - the injected thermoplastic material can then be an injected polypropylene, an acrylonitrile butadiene styrene, a polycarbonate, or a polyethylene, in particular in the form of granules from recycling, or in the form of material scraps (i.e. co-products not initially recovered) from the activity of a component production plant, in particular automotive components.

[0026] The invention thus provides a piece of clothing for a vehicle or other structure, comprising a thermoplastic structure at the rear of an appearance layer exterior. Originally, the exterior appearance layer is regular and has a heterogeneous appearance.

[0027] It is specified that the thermoplastic structure can be made of a charged material, for example with mineral particles, or uncharged.

[0028] The part may be an automotive part, such as a door panel, center console, or dashboard. The part may generally be an interior passenger compartment or bodywork part. It may also be a bottle or packaging, or a POS display.

[0029] The invention will now be described in relation to the appended figures, which are provided for illustrative and non-limiting purposes.

[0030] [Fig.l] is a schematic representation of the preliminary elements of the implementation of a method according to the invention.

[0031] Figures 2 and 3 are schematic representations of the preliminary elements of the implementation of a method according to the invention.

[0032] Figures 4 and 5 are visuals of surfaces obtained according to the methods of the invention.

[0033] [Fig.l] In [Fig.l] a preliminary and essential phase of the method according to the invention is shown, used for all embodiments thereof.

[0034] Pieces of thermoplastic material 10 are used, and they are for example manufactured by a grinding step, E1, of recovered materials, originating from the industrial site concerned or from a nearby site, such as offcuts, scraps, waste from series production. They can alternatively be obtained from a producer of polymer products called "compound" - it can be a mixture whose base is high-density polyethylene or a bioplastic, or any other thermoplastic base. The granules or scraps can contain - or can be added for the purpose of the press - fibers or mineral fillers, such as reed, shells, or by-products of the industry, such as scraps of leather pieces, textiles or other plastics, or fibers such as wool or polyester fibers, synthetic fibers, natural fibers. The quality is controlled.

[0035] Essentially, the material used is visually heterogeneous. This aspect will be discussed below.

[0036] These granules are placed in a press, during a step E2. The press used is a set of heating plates: a lower plate, flat, placed horizontally, and an upper plate, also flat. The plates are brought to a temperature sufficient to allow the melting of the material of the thermoplastic granules 10. The pieces resulting from the grinding are further placed and distributed on the lower plate in a fairly uniform manner, to ultimately allow the formation by pressing the upper plate on the lower plate of a continuous, non-perforated film of speckled thermoplastic material 20. The speckling is achieved because the plastic was not stretched through a die or between two rollers, but pressed between two plates, which allowed the initial heterogeneity of the thermoplastic mixture to remain visible.

[0037] During the descent of the upper plate, the granules are melted and, during a step E3, the product is obtained which has the appearance of a more or less thick sheet, depending on the setting of the press (pressure and temperature, as well as duration).

[0038] The precise thickness of the film 20 of thermoplastic material can be adapted according to the quantity of material introduced between the two plates of the press and the pressure which is applied by the upper plate on the lower plate. Thus the film can have the appearance of a plate. The thickness of the film or plate is generally uniform over the entire surface, and this is obtained if the upper plate has a surface parallel to the surface, placed horizontally, of the lower plate. Moreover, unless the surface of the upper plate has been worked to present a roughness, the layer is of smooth appearance. In any case, it is regular.

[0039] Essentially, as stated, the material used is heterogeneous, and the thickness of the film or plate is thin enough that, given the scale of the heterogeneity of the raw material, it remains visible after compression, while achieving sufficient mechanical cohesion so that the plate can be moved and used in subsequent stages of the process, and is also surface-resistant once the final product is finished.

[0040] This film constitutes a decoration aimed at highlighting the eco-responsible aspect of the structural part on which it will be affixed. Indeed, different colors from the different plastic parts initially used, and / or different inclusions, such as textile, reed, leather, shells, cork, are visible on the surface.

[0041] The pressing can be maintained for 50 seconds to 2 minutes, at a temperature of the plates previously established between 190 and 220°C, for example, and a pressure between the two plates which can be 2 to 3 bars.

[0042] [Fig.2] In [Fig.2] a thermocompression step E4 is shown in a mold, which constitutes the implementation of a first particular mode of the invention, using the film (or plate) manufactured in [Fig.l].

[0043] Thus, in a mold comprising a first impression or shape and a second complementary impression or counter-shape of the first, the sheet 20 and a plate of natural fiber NFPP (Natural fiber and polypropylene, thermoplastic material reinforced with natural fibers) 30 are placed. The NFPP plate can be 2 to 3 mm thick maximum after thermocompression, the essential thing being to ensure the function of structuring and structural maintenance of the part which is formed at that time. After thermocompression, the decorative film is embedded in the thickness of the composite assembly, the whole constituting a part varying from 2 to 3.5 mm in thickness.

[0044] The sheet 20 and the plate 30 are placed parallel to each other and the deformation caused by the shapes of the mold, in particular complementary shapes of the two parts of the shape mold, is then applied to them.

[0045] At the end of this thermocompression step, carried out in the presence of heat in the mold, a composite part 40 of the desired geometry is obtained, having two faces: a continuous outer face formed by the film 20 to which the mold has given the desired shape, and an inner face formed by the plate 30, to which the desired shape has also been given by the mold.

[0046] The two thicknesses, the sheet 20 and the plate 30, are at the end of step E4 intimately joined on all their surfaces brought into contact, due to the physicochemical compatibility of the materials chosen for this purpose.

[0047] Instead of NFPP, a synthetic non-woven fabric made of polyester and polyethylene can be used. Once compressed, this has sufficient strength and rigidity to constitute a structural element of a passenger compartment. Its material is derived from the recycling of fibers used in other circumstances. In addition, the materials of the two layers are sufficiently close chemically to ensure good long-term consistency after the fixing heat treatment.

[0048] [Fig.3] In [Fig.3] a step of a second embodiment of the invention is shown, an alternative to the embodiment shown in [Fig.2], and which therefore follows the steps of [Fig.1]. During this injection step E14, the sheet of thermoplastic material 20 is placed alone between the male part and the female part of an injection mold. Again, heat is applied, but in addition, the mold is equipped with injection nozzles and an injection of an injectable (liquid) material (preferably recycled) 35, with thermoplastic characteristics, is carried out on one of the faces of the sheet of thermoplastic material 20. This is a polymer which can optionally be loaded, for example a polypropylene, the characteristics of which are chosen according to the destination in the final assembly.This injection process coupled with thermomolding results in the preparation of a composite element 45 formed by the overmolding of a layer of new or recycled thermoplastic material in contact with the sheet of thermoplastic material 20 from [Fig.l]. The two layers of material are intimately linked by their physicochemical compatibility, by the physicochemical compatibility of the materials chosen for this purpose, and the shape is dictated by the impressions present in the thermocompression mold.

[0049] A product is obtained in which essentially only one type of material is ultimately present, which allows it to be recycled at the end of its life, since there is no need to separate different materials. For example, the outer appearance layer is manufactured from from various and heterogeneous scraps of recovered polypropylene and the structural layer is made of new polypropylene to guarantee the mechanical and dimensional strength of the part when a source of recycled material does not allow it.

[0050] And the principles of the invention can be applied to polycarbonate, acrylonitrile butadiene styrene or even polyamide or polyethylene.

[0051] [Fig.4] In [Fig.4] a possible aspect implemented in the invention. We see a thermoplastic sheet 100 with a surface that is very valuable for design in the field of internal automobile surfaces, or also on external vehicle surfaces.

[0052] [Fig.5] [Fig.5] also represents an alternative, with a surface 101 presenting a visible appearance of recovered material type. It should be noted that the product is not necessarily rigid: it can be flexible: “soft” or soft.

[0053] Finally, the method according to the invention, in the first and / or second of these embodiments, allows the development of new passenger compartment elements for a motor vehicle, or also new external bodywork elements for the motor vehicle. Materials from series production and not used initially can be used in the form of recovered material to make a plastic plate or film. An innovative aesthetic effect is obtained, as shown in Figures 4 and 5. The quantity of new material used is reduced.

[0054] The recovered material is highlighted for the end customer who perceives the circular economy aspect, which is interesting for the satisfaction of the purchase. A decorative effect of different types can be obtained depending on the choice of the raw material used. The part concerned can be, in addition to the examples considered above, also an element of a door strip, an armrest, or a door medallion. The two solutions, overmolding and thermocompression, are complementary, and allow adaptation to the structural material that has been chosen to use, and to the geometry requested by the designers of the final product. In the end, the part is structurally solid, its manufacture is economical in raw materials and its appearance is decorative and new and highlights the eco-responsible aspect of the part to make the end customer perceive the respectful use of materials and the circular economy in which the part is inserted.

Claims

Claims

1. Method for manufacturing a piece of clothing (40; 45) for a structure, comprising a step of assembling (E4; E14) a thermoplastic structure (30; 35) behind an external appearance layer (20), characterized in that the external appearance layer (20) is formed beforehand by pressing (E3) between two horizontal heating plates (E2) a mixture comprising pieces of recovered thermoplastic parts (10) ground (El) and dispersed on the lower plate.

2. Method of manufacturing a piece of clothing for a structure according to claim 1, characterized in that the mixture is visually heterogeneous (10) and it comprises several juxtaposed colors, by the inclusion of pieces of recovered parts of different colors.

3. Method of manufacturing a piece of clothing for a structure according to claim 1, characterized in that the mixture is visually heterogeneous and it comprises pieces of textile, pieces of reed, pieces of cork, pieces of leather, pieces of shells, visible, mixed with the pieces of thermoplastic part.

4. Method of manufacturing a piece of clothing for a structure according to one of claims 1 to 3, characterized in that the assembly (E4) is a thermocompression of the outer appearance layer (20) with a thermoplastic structural layer (30).

5. Method of manufacturing a piece of clothing for a structure according to claim 4, characterized in that the thermoplastic structural layer (30) is a layer of a matrix reinforced with natural fibers.

6. Method of manufacturing a piece of clothing for a structure according to claim 4, characterized in that the thermoplastic structural layer (30) is a layer of non-woven polyester and polypropylene fibers.

7. Method of manufacturing a piece of clothing for a structure according to claim 1 or claim 2, characterized in that the assembly (E14) is an overmolding of thermoplastic material (35).

8. A method of manufacturing a piece of clothing for a structure according to claim 7, characterized in that the thermo-material plastic is polypropylene from scraps co-produced by factory production of components.

9. Method of manufacturing a piece of clothing for a structure according to one of claims 1 to 7, characterized in that the piece (40; 45) is a part of the interior of a passenger compartment or exterior of a vehicle.

10. Clothing piece (40; 45) for a structure, which piece (40; 45) is obtained by implementing the method according to any one of claims 1 to 9 and comprises a thermoplastic structure (30; 35) at the rear of an external appearance layer (20), which external appearance layer (20) is regular and has a heterogeneous appearance (10).

11. A piece of clothing according to claim 10, characterized in that the part is an automobile part, such as a door panel, central console, or dashboard.

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