Method for manufacturing interior trim parts for vehicles

Abstract

This invention relates to a method for manufacturing interior trim for vehicles, comprising the steps of: providing a carrier film; forming a layered composite by applying a decorative surface layer to a first side of the carrier film; microperforating the decorative surface layer in one or more regions or over the entire surface; placing or pulling the layered composite consisting of the carrier film and the microperforated decorative surface layer into a cavity of an injection mold, such that when plastic is injected into the cavity, the decorative surface layer of the layered composite is injected from the back side, and a second side of the carrier film opposite the first side is pressed against the wall of the cavity; closing the cavity and injecting plastic into the cavity to form a carrier for the trim, wherein the decorative surface layer is injected from the back side, and when the carrier is formed in the cavity, the decorative surface layer is applied to the surface of the carrier facing the decorative surface layer, thereby forming a decorative layer for the trim; opening the cavity and removing or ejecting the trim.

Description

[0001] This invention relates to a method for manufacturing interior trim pieces for vehicles. The trim piece to be manufactured includes a carrier and a trim layer applied to the carrier, wherein the front side of the trim layer opposite to the carrier forms the visible surface of the trim piece.

[0002] Generally, in the design of vehicle interiors, a seamless, unified design surface is desired. Therefore, it is desirable to integrate the functions of necessary operating elements and / or display elements and / or lighting elements, as well as other devices, into the trim. Thus, the visible surface of the trim should, for example, integrate actuation functions and / or information functions and / or lighting functions, replacing these functions as separate devices. To meet the expectation of a seamless, unified design surface, there is a requirement that these functions integrated into the trim be formed in such a way that they are invisible when not in use; that is, when not in use, an observer on the visible surface of the trim should see a seamless, unified design surface. Functions or functional components should only be visible when in use, i.e., in the active state. In the inactive state, functions or functional components (e.g., switches, buttons, and displays) should be invisible. In this case, the visible surface of the trim is not interrupted, and the design appears seamless, continuous, and unified to the observer.

[0003] For example, it is known to integrate displays into interior trim pieces of vehicles. These displays have a display area that is integrated into the visible surface of the trim piece, thus appearing as a black or dark surface when not in use. These black or dark surfaces contrast with the rest of the trim piece's design and are considered unattractive. Therefore, it is desirable that the display, or its display area, be visible on the trim piece's visible surface only when the display is turned on and there is a display on the display area.

[0004] The objective of this invention is to provide a novel method for manufacturing decorative components, particularly a method for manufacturing decorative components that meet the aforementioned requirements. Preferably, this method should enable the simple and / or low-cost manufacture of decorative components.

[0005] This task is accomplished by a method having the features of claim 1. Advantageous embodiments and improvements are given in the dependent claims.

[0006] The method according to the invention is configured for manufacturing interior trim pieces for a vehicle, wherein the trim piece includes a carrier and a trim layer applied to the carrier, wherein the front side of the trim layer opposite to the carrier forms the visible surface of the trim piece.

[0007] The method according to the present invention includes the following steps:

[0008] a) Provide a carrier membrane,

[0009] b) A layered composite is formed by applying a decorative topcoat to the first side of the carrier film.

[0010] c) in one or more areas or on the entire surface Micro-perforation of the decorative surface layer,

[0011] d) The layered composite consisting of a carrier film and a micro-perforated decorative surface layer is placed or pulled into the cavity of an injection mold, such that when plastic is injected into the cavity, the decorative surface layer of the layered composite is subjected to back-side injection (hinterspritzen), and the second side of the carrier film opposite to the first side is pressed against the wall of the cavity.

[0012] e) The cavity is closed and plastic is injected into the cavity to form a carrier for the decorative element, wherein the decorative surface layer is injected from the back side, and thus, as the carrier is formed in the cavity, the decorative surface layer is applied to the surface of the carrier facing the decorative surface layer, thereby forming the decorative layer of the decorative element.

[0013] f) Open the cavity and remove or eject the decorative piece.

[0014] Due to the pressure of the plastic injected in step e), the carrier membrane is pressed against the wall of the cavity. Here, the decorative layer, such as a paint layer, bonds to the plastic based on the temperature and / or pressure of the injected plastic. Simultaneously, the decorative layer can be separated from the carrier membrane, but this is not mandatory.

[0015] Microperforation is understood as introducing a large number of through-holes into a decorative surface layer. The decorative surface layer is removed in the areas of the holes. The cross-sectional dimensions of these holes are, for example, in the range of 50 μm to 150 μm, such as 90 μm. All holes can be uniformly distributed across the microperforated areas. In this case, the hole density is constant. All holes can also have the same cross-sectional shape and size. For example, a circle can be considered as the cross-sectional shape. Therefore, circular holes can, for example, be uniformly distributed in the microperforated areas of the decorative surface layer. It is preferable to choose the hole diameter in such a way that the holes are not visible on the visible surface when viewed normally by an observer without auxiliary equipment or backlighting; that is, the observer only sees a uniform, continuous, and seamless design. Discontinuities in the design are only visible when the holes are backlit, for example, through a display. When the typical hole diameter is in the range of 50 μm to 150 μm, the hole spacing is typically in the range of 60 μm to 160 μm. Therefore, such microperforation has a resolution in the range of 423 dpi to 159 dpi. When the aperture spacing is 100 μm, the resolution is 254 dpi. Smaller aperture diameters within the range of less than 50 μm are also achievable, for example, smaller aperture diameters within the range of 10 μm to 50 μm. In this case, the aperture spacing can be, for example, between 12 μm and 60 μm, and the resolution can be in the range of 2117 dpi to 423 dpi.

[0016] Step g) can be performed directly after step f), or, if necessary, after other intermediate steps. Step g) proposes that the carrier film be removed upon removal or ejection, or after the decorative element is removed or ejected from the cavity, wherein the decorative surface layer remains on the carrier as a decorative layer. Alternatively, the carrier film may also remain on the decorative element.

[0017] If step g) is provided in the method according to the invention, the carrier film can also be a continuous film, with the decorative layer applied to the entire surface or partially on the continuous film. In this case, in step d), the area of ​​the carrier film with the decorative layer is pulled into the cavity, for example by automatic feeding. In step g), when the decorative piece is removed or ejected, the carrier film is separated from the now-manufactured decorative layer. The area of ​​the carrier film without the decorative layer is removed from the cavity, while another area of ​​the carrier film with the decorative layer is brought into the cavity according to step d), so that after the decorative piece is removed or ejected from the cavity, steps e), f), and g) can be repeated. This process can be repeated multiple times, especially automatically.

[0018] Alternatively, in step d), the carrier films of the decorative surface layer with microperforations are placed into the cavity, and then injected from the back side according to step e). In this case, the carrier films can also remain on the decorative piece after ejection. However, it is also possible to remove the carrier films after the decorative piece is removed or ejected according to step g) above. This process can also be automated.

[0019] The above embodiments demonstrate that creating microperforations in the decorative surface layer before applying it to the carrier enables a simple, efficient, and cost-effective method for manufacturing decorative parts.

[0020] By transferring the decorative surface layer applied to the carrier film, the decorative layer can be applied to the carrier in the manner provided according to the invention, thereby pre-treating the decorative surface layer before actual application. Micro-perforation is still performed on the carrier film for the decorative surface layer. Since the micro-perforations are through-holes, introducing them into the carrier may damage the carrier; for example, the laser beam used to form the holes may cause carrier turbidity. When micro-perforating the decorative surface layer on the carrier film, only the carrier film may be damaged; the decorative part to be manufactured does not require the carrier film and therefore the carrier film must be removed anyway.

[0021] Also advantageous is the vanishing effect when the micro-perforations are not backlit, meaning these perforations are invisible to the observer. In this case, the visible surface of the decorative element appears as a seamless, uniform, and continuous design surface without any distracting points. However, when backlit, the actuation and / or information and / or lighting functions integrated into the decorative element become visible. Therefore, they can replace separate devices for these functions.

[0022] An improved embodiment proposes that the plastic injected in step e) is a transparent plastic, and the resulting carrier is also a transparent carrier. This produces a decorative piece with relatively high transmittance. In the method according to the invention, turbidity or other damage to the transparent carrier during the introduction of microperforations is eliminated because the microperforations are already created in a pre-treated decorative surface layer on the carrier film for this purpose before the decorative layer is applied to the carrier, and then transferred to the carrier. This eliminates the possibility of poor light transmittance and / or variations in color reproduction, which could occur, for example, when microperforations are created in a decorative layer that has already been applied to the carrier.

[0023] According to an embodiment of the invention, the decorative part to be manufactured has a display. For example, after step f) or g), the display is mounted on the back side of the carrier opposite the decorative layer and / or in a groove of the carrier. The mounting is performed such that the display area of ​​the display faces the decorative layer, so that the display generated by the display area can be seen through the micro-perforations of the decorative layer on the visible surface of the decorative part.

[0024] Therefore, an observer can identify the display generated by the display area on the visible surface of the decorative piece. In any case, the display is visible when the viewing angle is 90°, that is, when the observer of the decorative piece is looking perpendicularly at the front of the decorative piece and thus parallel to the extension of the holes through the micro-perforations in the decorative layer.

[0025] At oblique viewing angles, i.e., angles between 0° (parallel to the front of the decorative element) and 90° (perpendicular to the front of the decorative element), visibility depends on the thickness of the decorative layer and the cross-sectional dimensions of the holes; specifically, in the case of circular holes, visibility depends on the diameter of the holes. With a constant cross-sectional dimension, the thinner the decorative layer, the smaller the viewing angle from which the observer can still see the display. Furthermore, it also applies that with a constant decorative layer thickness, the larger the cross-sectional dimension, the smaller the viewing angle from which the observer can still see the display. To still achieve a high-resolution visible display, the holes in the micro-perforations must be chosen to be as small as possible. Therefore, given a hole diameter, the thickness of the decorative layer determines the possible oblique viewing angles. Starting from a vertical viewing angle of 90°, the thinner the decorative layer, the smaller the viewing angle, thus allowing for a more oblique viewing of the display. Therefore, the method according to the invention enables decorative elements with micro-perforations that cover the display surface of a display, wherein the display shown by the display has relatively low viewing angle dependence, i.e., the display remains visible from a viewing angle perpendicular to the front of the decorative layer up to smaller viewing angles. Thus, the displays inside the vehicle are visible or readable to observers in different positions. This visibility can be adjusted by appropriately selecting the ratio of the thickness of the decorative surface layer or decorative layer to the diameter of the holes in the decorative surface layer or decorative layer; that is, the display remains visible or readable at the minimum viewing angle or the maximum deviation from the vertical.

[0026] Another advantage of the method according to the invention is obtained from the pre-fabricated microperforations still present on the carrier film. The edges of the perforations form relatively high edge sharpness at the ends of the perforations on the side facing the carrier and / or the side facing the visible surface. This results in a relatively accurate and uniform display or visibility of the display to the observer.

[0027] Another advantage of the microperforations in the decorative layer, manufactured according to the method of the present invention, along with the display, is that they reproduce the brightness and color coordinates of the display visible through the microperforations very well.

[0028] Microperforations have been created in the decorative layer on the carrier film, and relatedly, turbidity and / or color reproduction variations in the transparent carrier are avoided. In terms of displays, this offers the advantage of using more advantageous display technologies with lower brightness intensities. Due to the lower required brightness intensity, heat sinks can also be omitted or made smaller.

[0029] Different types of displays can be considered, such as LCD, LED, or PLED displays.

[0030] According to one embodiment, in step e), during injection, the plastic penetrates the microperforations created in step d), and the microperforations are partially or completely filled with the injected plastic.

[0031] The injected plastic may be polyurethane (PUR) and / or polycarbonate (PC), or the injected plastic may include polyurethane (PUR) and / or polycarbonate (PC).

[0032] In step c), microperforation is performed on the decorative surface layer, i.e., pores are introduced into the decorative surface layer, for example, by laser. However, this may damage the carrier film. However, since the carrier film will be removed from the decorative piece anyway, this is harmless. On the other hand, if microperforation is formed into the decorative layer that has already been applied to the carrier, it may have adverse effects on the carrier, such as adverse effects due to turbidity and / or color changes.

[0033] The carrier film provided in step a) can be a hot stamping film and / or an IMD film, i.e., a film suitable for a method known as in-mold decoration (IMD). Therefore, step e) can be hot stamping, in which the decorative layer is transferred from the carrier film to the carrier by heat and / or pressure during carrier manufacturing.

[0034] For example, the carrier membrane has a thickness on the order of approximately 200 μm.

[0035] The decorative finish applied in step b) can be a paint layer and / or a pigment layer.

[0036] For example, decorative layers can be applied to a carrier film using an embossing process.

[0037] A variation of this method proposes applying a protective layer and / or an optical layer to the front side of the decorative layer, particularly after step f) or g). The protective layer and / or optical layer may comprise, or be formed of, PUR and / or thermoplastic materials.

[0038] As an intermediate step or after the described method steps, known method steps for the final processing of the molded part may be performed, such as cutting and / or milling and / or grinding steps.

Claims

1. A method for producing a trim part for a vehicle interior, wherein the trim part comprises a carrier and a decorative layer applied to the carrier, wherein the front side of the decorative layer opposite the carrier forms the visible side of the trim part, wherein the method comprises the following steps: a) providing a carrier film, b) forming a layer composite by applying a decorative face layer on a first side of the carrier film, c) micro-perforating the decorative face layer in one or more regions or over the entire surface, wherein the micro-perforation of the decorative face layer introduces a plurality of through-holes into the decorative face layer by removing the decorative face layer in the region of the through-holes, the size of the through-holes being selected such that the through-holes cannot be seen by an observer when viewing the visible side of the trim part without auxiliary equipment and without backlighting, d) placing or drawing the layer composite consisting of the carrier film and the micro-perforated decorative face layer into a cavity of an injection mold such that the decorative face layer of the layer composite is injected from the back side when plastic is injected into the cavity, and here the second side of the carrier film opposite the first side is pressed against the wall of the cavity, e) closing the cavity and injecting plastic into the cavity to form the carrier of the trim part, wherein the decorative face layer is injected from the back side, and as a result of this the decorative face layer is applied to the surface of the carrier facing the decorative face layer when the carrier is formed in the cavity, and thereby the decorative layer of the trim part is formed, f) opening the cavity and removing or ejecting the trim part.

2. The method of claim 1, wherein, After step f) the following step follows: g) removing the carrier film upon removal or ejection, or after the trim part has been removed or ejected from the cavity, wherein the decorative face layer remains as a decorative layer on the carrier.

3. The method according to claim 1 or 2, characterized in that, The plastic injected in step e) is a transparent plastic, and the carrier formed is a transparent carrier.

4. The method of claim 3, wherein, The trim part to be produced has a display, wherein the display is mounted in a recess in the carrier opposite the decorative layer and / or on the back side of the carrier, wherein the mounting is carried out in such a way that the display area of the display faces the decorative layer, and a display generated by the display area is therefore visible in the visible side of the trim part through the micro-perforation of the decorative layer.

5. The method according to any of the preceding claims, characterized in that, In step e) the plastic penetrates the micro-perforation produced in step d) upon injection, and the micro-perforation is partially or completely filled with the injected plastic.

6. The method according to any of the preceding claims, characterized in that, The injected plastic is polyurethane PUR and / or polycarbonate PC, or the injected plastic comprises polyurethane PUR and / or polycarbonate PC.

7. The method according to any of the preceding claims, characterized in that, In step c) the micro-perforation of the decorative face layer is carried out by means of a laser.

8. The method according to any of the preceding claims, characterized in that, The carrier film provided in step a) is a stamping film and / or an IMD film.

9. The method according to any of the preceding claims, characterized in that, The decorative face layer applied in step b) is a paint layer and / or a pigment layer.

10. The method according to any of the preceding claims, characterized in that, A protective layer and / or an optical layer is applied on the front side of the decorative layer.