Painted and translucent component

Abstract

Painted and translucent component (1), in particular vehicle trim part, comprising: a. A base body (2) made of a transparent or translucent plastic. b. A paint coating (3) on the base body (2), wherein the paint coating (3) comprises at least one structured paint coating layer (3b). c. A top layer (5) made of a transparent plastic applied to the paint coating (3) by reaction injection molding.

Description

[0001] The present invention relates to a painted and translucent component, in particular a vehicle trim part.

[0002] Such components are known, for example, from DE10 2006 046 436 B3 or EP 4 389 386 A1.

[0003] The known vehicle body panels typically comprise a layered structure that results either from printing processes, a combination of printing and reaction injection molding processes, a combination of spray painting processes, or a combination of spraying and printing processes.

[0004] The disadvantages of such vehicle body panels are, on the one hand, the poor surface quality and, on the other hand, insufficient protection against stone chips. The lack of protection stems from the topcoat layer, applied in traditional methods in thin layers of less than 100 µm, which is typically penetrated by sharp-edged debris encountered during use. This thin layer also means that areas with changes in wall thickness in the underlying paint layers are inadequately compensated for, resulting in a visually noticeable surface irregularity. Furthermore, when using printed inks, achieving a color match with other components colored in the same shade is difficult.

[0005] The invention is based on the objective of providing a painted and translucent component that solves the problems known from the prior art, has an improved surface quality, reliably protects the paint layer from damage caused by external influences, and also enables better color matching with similarly colored components.

[0006] To solve this problem, the invention discloses the component according to claim 1. Disclosed is a painted and translucent component, in particular a vehicle trim part, comprising: A base body made of a transparent or translucent plastic. A colored coating on the base body, wherein the colored coating comprises at least one structured layer of colored coating. A top layer made of a transparent or translucent plastic, applied to the paint coating using reaction injection molding.

[0007] The topcoat applied using reaction injection molding protects the underlying paint finish from damage caused by external influences and offers a higher surface quality than previously known solutions. Furthermore, the paint finish enables better color matching compared to printing inks.

[0008] Beneficial further training courses are subject to dependent claims.

[0009] It can be advantageous if the base body is an injection-molded component. The advantages of injection-molded components include, in particular, cost-efficiency and economy (low unit costs, high throughput, low material consumption), low weight (increased efficiency and convenience), design freedom (complex shapes, integrated functions, variable wall thicknesses without post-processing), precision and consistency (tight tolerances, identical parts across production runs), durability (impact, scratch, and weather resistant, long-lasting), and fast cycle times (automated processes shorten lead times).

[0010] It can prove advantageous if the base body is made of polycarbonate. Polycarbonate is particularly suitable for injection-molded vehicle body panels because it is lightweight, impact-resistant, and dimensionally stable. It offers high transparency and resistance to chemicals. Its thermal stability ensures it remains dimensionally stable even at extreme temperatures. The material allows for complex shapes in injection molding and is fully recyclable – a significant advantage in terms of sustainability. Furthermore, polycarbonate is considerably lighter than glass. Therefore, polycarbonate is especially well-suited as a material for the base body of the translucent component.

[0011] It can be advantageous for the paint coating to have at least one adhesion promoter layer between the base material and the textured paint layer, preferably a primer suitable for laser processing. The adhesion promoter significantly improves the bond between the paint layer and the base material by optimally preparing the base material's surface for coating. It ensures even paint distribution, protects against external influences such as moisture or UV radiation, and increases chemical and mechanical resistance. Thus, the adhesion promoter layer contributes significantly to the durability and quality of the paint system applied to the base material.

[0012] It can prove practical if the colored coating has at least one clear coat layer on the side of the structured colored coating layer facing away from the base material. This clear coat layer is preferably structured analogously to the structured colored coating layer, or the clear coat layer completely covers the structured colored coating layer. The outer clear coat layer encapsulates the colored coating. Consequently, soot from laser ablation cannot adhere to the surface of the colored coating layer and is easier to remove by cleaning the clear coat, thus simplifying the manufacturing of the component. The clear coat layer can be structured, for example, by subsequent material removal analogous to the structured colored coating layer, such as by using a laser to create a textured pattern in the colored coating from the outside.Alternatively or additionally, a mask or stencil can be applied to the clear coat layer before removal, ensuring that the masked / stenciled areas of the base body remain free of clear coat. The clear coat can also completely cover the textured base coat layer. It can be advantageous to texture the base coat layer by masking and / or stenciling the base body before applying the base coat layer and / or by material removal, preferably by laser ablation, after applying the base coat layer. Targeted material removal allows for the selective removal of the opaque base coat layer to achieve specific backlighting effects.By masking or stenciling, areas of the base body can be kept completely free of paint coating without material removal, so that the surface properties of the base body are not affected by any material removal from the applied paint layer. This improves the light quality when backlighting the vehicle part in the structured areas of the paint layer.

[0013] It can be helpful if the topcoat on the side facing the paint finish has a structure complementary to that of the textured paint layer and, if applicable, the clear coat. This prevents air inclusions in the topcoat material from impairing the light quality when the vehicle part is backlit through the perforated areas of the paint finish. Ideally, the topcoat on the inner side facing the paint finish should have a complementary structure, essentially acting as a negative image of the paint layer and, if applicable, the clear coat, to completely compensate for any irregularities resulting from the texture of the paint layer and, if applicable, the clear coat, without air inclusions. The topcoat on the outer side, which is not exposed to the paint finish, should ideally have a smooth surface. This is particularly well achieved using reaction injection molding. This allows for optimal concealment of variations in wall thickness in the underlying paint layers.

[0014] It can be advantageous if the topcoat has a thickness in the range of 0.1 mm to 3.0 mm, preferably a thickness in the range of 0.5 mm to 0.8 mm. With increasing thickness of the topcoat, the paint finish is better protected against damage from external influences.

[0015] It can be advantageous if the top layer consists of polyurethane or polyurea, preferably as a cross-linked thermoset. Polyurethane is UV-stable, extremely resistant to wear, and flexible in its shaping. In vehicle body panels, the shock-absorbing properties of polyurethane increase safety, while good sound insulation and thermal insulation enhance the driving experience. Furthermore, polyurethane can be used sustainably and contributes to the longevity of modern vehicle components. The polyurethane top layer is preferably transparent or translucent, at least in its cured state and at least in the perforation area. Purely unpigmented polyurethane coatings produced by reaction injection molding appear naturally clear to slightly yellowish-transparent, as the polyols and isocyanates used impart a honey tint.To achieve a specific color or increase UV stability, liquid dyes or color concentrates (masterbatches) can be added to the mixing process, making it possible to create virtually any color (especially RAL or metallic shades). However, formulation parameters such as hardness, crosslinking density, and fillers (like glass beads or talc) slightly influence the final color, which is why laboratory tests to fine-tune chemical resistance and desired appearance are standard practice before mass production begins.

[0016] It can be advantageous if the component is designed as an exterior part, particularly as a panel, spoiler, bumper, front or rear triangular window trim (BDH, BDV), or radiator grille. The light effects achievable through backlighting are especially beneficial with such components.

[0017] A method for manufacturing a painted and translucent component, in particular the component according to one of the preceding descriptions, is also disclosed, comprising the following steps: Step A: Provide a base body made of a transparent or translucent plastic. Step B: Creating a colored coating with at least one textured layer of colored lacquer on the base body. Step C: Applying a top layer of transparent plastic to the colored coating using the reaction injection molding process.

[0018] It can be advantageous to apply the paint finish in step B using wet painting. Wet painting offers high flexibility in terms of color, gloss level, and surface texture, and is particularly suitable for painting transparent or translucent plastic base bodies. It allows for thin, uniform layers with excellent adhesion and provides outstanding chemical protection. Wet painting is ideal, especially for complex component shapes such as vehicle body panels, or when special visual effects are desired. Furthermore, wet painting facilitates the creation of composite systems and multi-colored designs.

[0019] It can be advantageous to structure the paint layer by masking and / or stenciling the substrate before applying the paint layer and / or by material removal, preferably by laser ablation, after application. This allows for particularly precise structuring of the paint layer and targeted limitation / blocking of the area on the substrate surface. It can also be beneficial to subject the paint layer to physical, chemical, and / or mechanical cleaning between steps B and C, especially to remove material residues resulting from material removal in step B. This ensures optimal bonding of the topcoat to both the perforated paint layer and the exposed sections of the substrate, preventing material inclusions between the paint layer and the topcoat.

[0020] It can be helpful to subject the paint coating in step C to surface activation before applying the topcoat. Surface activation performed before the reaction injection molding process significantly improves the adhesion between the painted component and the applied material. Processes such as plasma or laser treatment remove contaminants and increase the surface energy, allowing the reactive components to wet better and bond chemically or mechanically. Terms and Definitions: Reaction Injection Molding (RIM) Basic Principle

[0021] Reaction injection molding is a plastic molding process that operates at low pressure (e.g., up to 200 bar) and moderate temperatures (down to -120 °C mold temperature). Two reactive liquids—typically a polyol and an isocyanate—are stored separately in tanks and mixed together just before injection into a temperature-controlled mold. The subsequent chemical reaction generates heat, causing the mixture to harden and forming lightweight yet high-strength components.

[0022] The main advantages of reaction injection molding are the high design flexibility (complex geometries, variable wall thicknesses and undercuts are possible), the cost efficiency, short cycle times due to fast reaction and curing) and the excellent surface quality and detail accuracy. Textured paint layer

[0023] The textured paint layer exhibits irregular irregularities or patterns that distinguish it from a completely smooth paint layer. The textured paint layer is therefore not smooth, but rather has openings or perforations, raised areas, depressions, grooves, or other patterns that are preferably perceptible to the naked eye.

[0024] The texture of the paint layer can be created, for example, by material removal, particularly by laser ablation. Alternatively or additionally, a mask can be applied to the base material before the paint is applied, so that only part of the base is painted. The mask is then removed from the base material after painting. Alternatively or additionally, the paint can be applied using stencils. Unlike a mask, which is generally intended for single use and is destroyed when removed from the base material, a stencil is designed for multiple uses.

[0025] Material removal can, for example, create perforations in the paint finish. However, it is also possible to remove material from specific areas of the paint finish using various techniques.

[0026] The unstructured paint layer is preferably opaque. Structuring allows the opacity of the paint layer to be selectively reduced or even completely eliminated in specific areas. Structuring the paint layer is particularly useful for creating specific translucent effects by selectively reducing its opacity. Brief description of the characters

[0027] They show: Fig. 1 A schematic sectional view of a component according to the first embodiment. Fig. 2 a schematic sectional view of a component according to the second embodiment. Detailed description of preferred embodiments

[0028] The preferred embodiments are described in detail below with reference to the accompanying figures.

[0029] Fig.Figure 1 shows a schematic sectional view of a component 1 according to the first embodiment. The component 1 comprises an injection-molded, translucent base body 2 made of polycarbonate and a paint coating 3 applied using a wet paint process and subsequently structured and perforated by laser ablation. The paint coating 3 is a paint system with an opaque laser primer 3a as an adhesion promoter layer and a structured paint coating layer 3b consisting of a base coat with hardener. Preferably, after chemical / mechanical cleaning and / or surface activation of the perforated paint coating 3, a top layer 5 made of translucent polyurethane is applied to the paint system 3 using a reaction injection molding process to a thickness of approximately 2 mm. The top layer 5 completely fills the structuring or perforations 4 in the paint coating 3 and is directly bonded to the base body 2 through these perforations 4.Component 1 is, for example, a vehicle trim part such as a bumper or a radiator grille. However, the component can also be any other exterior component, such as a panel, a spoiler, a bumper, or a trim part for the front or rear triangular window (A-pillar: BDV; C-pillar: BDH).

[0030] Component 1 according to the second embodiment is essentially identical to the first embodiment and differs from it only in that the colored coating 3 has an outer clear coat layer 3c outside the colored coating layer 3b. Optionally, a further clear coat layer (not shown) can be provided on the underside or inside of the colored coating layer 3b as a sacrificial / protective layer for laser ablation.

[0031] The clear coat layer 3c is applied as a protective layer to the color coat layer 3b and subjected to a drying process. After drying, the component 1, coated with the reduced clear coat layer 3c, is subjected to laser processing (step B) to structure the color coat layer 3b and the clear coat layer 3c. The dirt adhering to the color coat 3 after laser ablation is then no longer located on the base coat of color coat layer 3b, but on the protective clear coat layer 3c. The ablated material can then be easily removed by physical, chemical, and / or mechanical cleaning of the color coat 3 in preparation for the subsequent reaction injection molding process (step C).

[0032] The main advantages of the preferred embodiments result from the PU protective layer applied by reaction injection molding on a structured paint layer produced in the wet paint process and lie in higher surface protection, higher surface quality (laser areas) and color match. Reference symbol list 1 component 2 base bodies (transparent / translucent) 3. Color coating / color coating system 3a Primer 3b Paint layer 3c clear coat 4. Structuring or perforation / perforations 5 Top layer (transparent / translucent, possibly colored) QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2006 046 436 B3

[0002] EP 4 389 386 A1

[0002]

Claims

[1] Painted and translucent component (1), in particular vehicle trim part, comprising: a. A base body (2) made of a transparent or translucent plastic. b. A paint coating (3) on the base body (2), wherein the paint coating (3) comprises at least one structured paint coating layer (3b). c. A top layer (5) made of a transparent plastic applied to the paint coating (3) by reaction injection molding. [2] Component (1) according to the preceding claim, characterized by , that the base body (2) is an injection-molded component. [3] Component (1) according to any of the preceding claims, characterized by , that the base body (2) is made of polycarbonate (PC). [4] Component (1) according to any of the preceding claims, characterized by, that the paint coating (3) between the base body (2) and the structured paint coating layer (3b) has at least one adhesion promoter layer (3a), preferably a primer suitable for laser processing. [5] Component (1) according to any of the preceding claims, characterized by , that the paint coating (3) on the side of the structured paint coating layer (3b) facing away from the base body (2) has at least one clear coat layer (3c), wherein the clear coat layer (3c) is preferably structured analogously to the structured paint coating layer (3b) or the clear coat layer completely covers the structured paint coating layer (3b). [6] Component (1) according to any of the preceding claims, characterized by, that the paint layer (3b) is structured by masking and / or stenciling the base body (2) before the application of the paint layer (3b) and / or by material removal, preferably by laser removal, after the application of the paint layer (3b). [7] Component (1) according to any of the preceding claims, characterized by , that the top layer (5) on the side facing the color coating (3) is structured in a manner complementary to the structured color coating layer (3b) and, if applicable, clear coating layer (3c). [8] Component (1) according to any of the preceding claims, characterized by , that the top layer (5) has a thickness in the range of at least 0.1 to 3.0 mm, preferably a thickness in the range of 0.5 to 0.8 mm. [9] Component (1) according to any of the preceding claims, characterized by , that the top layer (5) consists of polyurethane or polyurea, preferably each as a cross-linked thermoset. [10] Component (1) according to any of the preceding claims, characterized by , that the component (1) is designed as an exterior component, in particular as a panel, spoiler, bumper, front or rear triangular window trim or radiator grille.

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