Method for selectively producing a first or second variant of a multi-layer plastic component

Description

[0001] The present invention relates to a method for selectively producing a first or a second variant of a multi-layer cladding part according to the preamble of patent claim 1.

[0002] Some BMW vehicle models are offered with different instrument panel variants, namely a base variant and an optional equipment variant. Both variants have a multi-layered structure consisting of a carrier part, a decorative layer, and a foam layer in between. <h2 style=";text-align:left;direction:ltr">Figure 1a shows a basic variant and <h2 style=";text-align:left;direction:ltr"> Figure 1b a special equipment variant which has the same total thickness D as the basic variant. As can be seen from the <h2 style=";text-align:left;direction:ltr"> Figures 1a, 1b As can be seen, the carrier part 1 of the basic variant is identical to the carrier part 1 of the special equipment variant. In the basic variant of the <h2 style=";text-align:left;direction:ltr"> Figure 1aA relatively thin decorative layer 2 made of plastic is provided, which can be provided with a leather-like grain on its upper surface, for example. The space between the carrier part 1 and the thin "plastic skin 2" is formed by a (semi-)rigid foam layer 3.

[0003] The special equipment variant of the <h2 style=";text-align:left;direction:ltr"> Figure 1b It has a somewhat thinner foam layer 3, to which a plastic skin 2 is also applied, which is no longer visible from the outside of the finished component. Its production requires a separate tool, which is associated with correspondingly high costs. A two-layer decorative layer is applied to the plastic skin 2, which consists of a shear-elastic layer 4 and a leather layer 5. The shear-elastic layer 4 can be formed by a "spacer fabric."

[0004] During the production of the two <h2 style=";text-align:left;direction:ltr"> Figures 1a, 1bIn the variants shown, the carrier part 1 is inserted into an upper tool half and the molded skin 2 into a lower tool half of a mold. The space between is then filled with foam. Since the foam layer 3 of the <h2 style=";text-align:left;direction:ltr"> Figure 1b shown special equipment variant is lower than that of the <h2 style=";text-align:left;direction:ltr"> Figure 1a In contrast to the basic version shown, a separate tool is required for each of the two variants, which is associated with high costs. The special equipment variant of the <h2 style=";text-align:left;direction:ltr"> Figure 1b Although the molded skin used is no longer visible from the outside of the finished product, it is required according to current knowledge because the spacer fabric 4 cannot be inserted directly into the foaming tool, as otherwise the plastic foam would penetrate into the spacer fabric 4 and harden it.

[0005] From the published patent application DE 10 2009 050 620 A1, which discloses the preamble of claim 1, a method for selectively producing a first or a second variant of a multi-layer plastic component is known.

[0006] DE 10 2011 005 343 A1 relates to an interior fitting for a vehicle, in particular a motor vehicle, comprising a carrier layer and a decorative layer as well as a haptic layer arranged between the decorative layer and the carrier layer.

[0007] From WO 86 / 05439 a method and a device are known for producing components from foamed plastic material.

[0008] From JP 2001 009 956 A an interior component and a method for its production are known.

[0009] In the prior art processes for manufacturing interior components or trim components, a foam surface is provided with a surface layer. This surface layer can be a decorative film or a layer of synthetic or genuine leather. Because the foam is very flexible, it is not possible to create distinctive contours on the surface of the component.

[0010] The object of the invention is to provide a method for selectively producing a first or a second variant of a multi-layer trim part that offers cost advantages over known methods. A specific object of the invention is to provide a method with which various designs of plastic components can be produced in a simple manner.

[0011] This object is achieved by the features of claim 1. Advantageous embodiments and further developments of the invention can be found in the subclaims.

[0012] The invention is based on a method for selectively producing a first or a second variant of a multi-layer trim part, such as an instrument panel cover for the passenger compartment of a vehicle. Both variants each comprise a carrier part, a "decorative layer," and a foam layer located between the carrier part and the decorative layer. The term "decorative layer" is to be understood as meaning that it can be a single layer or a decorative layer composed of several sublayers. In a first embodiment of the method, a first variant, for example a basic variant (standard equipment), can be produced. According to a second embodiment of the method, a different variant, for example a special equipment variant, can be produced.

[0013] For design reasons, however, both variants should have exactly or at least approximately the same surface contour (same radii of curvature, etc.).

[0014] Both variants can even have the same total thickness, whereby the thickness of the decorative layer of the first variant is smaller than the thickness of the decorative layer of the second variant and the thickness of the foam layer of the first variant is correspondingly greater than the thickness of the foam layer of the second variant.

[0015] The foam layer is produced in a foaming tool, which has a first tool half into which the carrier part is inserted before the foaming process begins. The carrier part can, for example, be inserted into an upper tool half of the foaming tool and held to the upper tool half by means of negative pressure, i.e., "sucked upward."

[0016] The core of the invention is that the foam layer has several regions with different contour strengths or contour stabilities. In predetermined areas of the trim part where distinct contours on the surface are desired, foam layer regions with high contour stability are created. This allows a soft feel to be maintained in the remaining areas where a flexible surface is desired. A trim part according to the invention is thus characterized by well-defined character lines while simultaneously maintaining a flexible feel.

[0017] To achieve these contour-stable properties, foam materials with different degrees of hardness can be used in different areas. This can be achieved by using different materials. Polyurethane (PUR) can also be used in both areas. In the latter case, the material properties of the polyurethane are achieved by appropriately adjusting the individual components.

[0018] First, a first component is applied to the decorative layer or the carrier layer. This component is sprayed onto areas that are to correspond to the contour-stable areas in the finished component. A second component is then sprayed onto areas that are to represent areas with a flexible feel in the finished cladding component. The mold is then closed, and the foam layer is formed in a foaming process.

[0019] According to the first embodiment, to produce the first variant, the decorative layer of the first variant is introduced into a second, e.g., lower, half of the foaming tool before the foaming process. According to the second embodiment, to produce the second variant of the plastic component, a "spacer layer" is introduced into the second half of the foaming tool before the foaming process. The spacer layer is removed from the foam layer after the foaming process, and the decorative layer of the second variant is applied to the foam layer.

[0020] In this way, two or more different variants of a multi-layer plastic component, whose individual layer thicknesses may vary but whose total thickness may be identical or approximately the same, can be manufactured using the same foaming tool. Alternatively, each variant can be manufactured in a separate, dedicated foaming tool.

[0021] The back of the spacer layer, also called dummy skin, is treated with a release agent. The back corresponds to the side of the spacer layer with which it comes into contact with one half of the tool. By inserting the spacer layer into the tool, an offset surface to the surface of the tool is created. During the production of a foam structure, the spacer layer is used to replace surface layers that are only applied to the foam structure after the foam structure has been completed. Such surface layers can be made of leather, artificial leather or similar materials, for example. After the surface layer has been applied, there is no excess material compared to a variant in which the surface layer is made of a film and is therefore much thinner.

[0022] The spacer layer is preferably reused, i.e., used to produce a plurality of second variants of the plastic component. It should be made of a material with a certain degree of elasticity, so that the spacer layer can be peeled off the foam layer without damaging the foam layer. Tests have shown that a spacer layer made of silicone or a silicone-containing material is very suitable for this purpose, while preventing the foam layer from "sticking" to the spacer layer. A spacer layer made of silicone or a silicone-containing material can be peeled off the foam layer without leaving any residue. However, the spacer layer can also be made of other materials without departing from the invention.

[0023] The foam layer can be a polyurethane foam layer.

[0024] Furthermore, the carrier part can be made essentially of expanded polypropylene.

[0025] The invention is explained in more detail below in conjunction with the drawings, which show an exemplary, schematic view: Figure 1a: A first variant of a multilayer plastic component according to the prior art; Figure 1b: A second variant of a multilayer plastic component according to the prior art; Figures 2a, 2b: Two variants of a multilayer plastic component.

[0026] The <h2 style=";text-align:left;direction:ltr"> Figures 2a, 2b show two different variants of a multi-layer plastic component.

[0027] A first embodiment of the invention is to be explained with reference to the <h2 style=";text-align:left;direction:ltr"> Figure 2a be explained. <h2 style=";text-align:left;direction:ltr"> Figure 2a shows analog <h2 style=";text-align:left;direction:ltr"> Figure 1aA basic variant comprising a carrier part 2, a decorative layer 2 formed by a molded skin, and a semi-rigid foam layer 3 located between them, connecting the carrier part 1 and the decorative skin 2, which can be made of polyurethane, for example. In its edge regions, this foam layer 3 has dimensionally stable regions 3a. A central region 3b is softer or more flexible than the dimensionally stable edge regions 3a. The multi-layer plastic component of the <h2 style=";text-align:left;direction:ltr"> Figure 2a has a total thickness D. Due to the dimensionally stable areas 3a, contours k can be created on the visible surface of the decorative layer 2, which are particularly clearly visible.

[0028] A second embodiment of the invention will be explained with reference to <h2 style=";text-align:left;direction:ltr"> Figure 2b be explained. <h2 style=";text-align:left;direction:ltr"> Figure 2bshows a special equipment variant in which the same carrier part 1 is used as in the basic variant. Alternatively, any other carrier part 1 can be used. During production, the carrier part 1 is first inserted into an upper tool of a foaming tool and held there, for example, by means of negative pressure. A spacer layer 6 made of a silicone material is inserted into the lower tool of the foaming tool (not shown). Analogous to the one with reference to <h2 style=";text-align:left;direction:ltr"> Figure 2aexplained embodiment, a foam layer 3 is also produced here which comprises more dimensionally stable regions 3a and softer regions 3b. In this second embodiment too, the harder regions 3a are provided at the edge of the component and the more flexible region 3b in the central region of the component. To produce these regions, a first component or a first material is first sprayed onto the carrier part 1 or the spacer layer 6 in the regions in which first regions 3a are to be formed on the finished component. Then, a second component or a second material is sprayed onto the carrier part 1 or the spacer layer 6 in the regions in which second regions 3b are to be formed on the finished component. After the foaming tool is closed, the space between the carrier part 1 and the spacer layer 6 is filled with foam, resulting in the foam layer 3 with the first regions 3a and the second regions 3b.As can be seen from the . <h2 style=";text-align:left;direction:ltr"> Figures 2a, 2b As can be seen, the foam layer 3 of the <h2 style=";text-align:left;direction:ltr"> Figure 2b shown variant is slightly thinner than the foam layer 3 of the <h2 style=";text-align:left;direction:ltr"> Figure 2a basic variant shown.

[0029] After foaming the foam layer 3, the foaming tool is opened and the back-foamed carrier part 1 is removed. After removal, the elastic spacer layer 6 is peeled off. Since the spacer layer 6 is made of a silicone material, the foam layer 3 does not adhere, or only slightly adheres, to the spacer layer 6. The spacer layer 6 can therefore be peeled off without leaving any residue and without damaging the top side 7 of the foam layer 3.

[0030] In the embodiment shown here, the spacer layer 6 is just as thick as the decorative layer formed by the spacer fabric 4 and the leather layer 5. After removing the "silicone layer 6," the decorative layer formed by the two layers 4, 5 is glued with the underside 8 of the spacer fabric 4 to the top side 7 of the foam layer 6, resulting in the finished instrument panel trim in its special version with leather upholstery. Analogous to the basic version, the <h2 style=";text-align:left;direction:ltr"> Figure 2b illustrated embodiment characteristic contours k. In this area, the decorative layer is supported by the dimensionally stable area 3a, so that well-defined contour lines are visible on the surface of the decorative layer.

[0031] As can be seen from the <h2 style=";text-align:left;direction:ltr"> Figures 2a, 2bAs can be seen, in the embodiment shown here both the basic variant and the special equipment variant have the same total thickness D. However, both variants do not necessarily have to have the same total thickness D.

[0032] As an alternative to a "two-layer" decorative layer formed from the two layers 4 and 5, a "single-layer decorative layer" could also be used for the second variant, which differs from the decorative layer of the first variant. For example, a synthetic or natural leather layer with a thickness ranging between 1.0 mm and 2 mm, or a plastic skin with a different texture and / or thickness than the decorative layer of the first variant, is conceivable.

[0033] The invention offers the advantage that contours created in a CAD system can be reproduced on the actual component with a high degree of detail. This is possible due to the use of dimensionally stable or hard foam materials in the areas of the trim part in which contours are to be represented. In these areas, the foam layer does not give way when the decorative layer is applied. A further advantage of the invention can be seen in the fact that a high gap quality can be achieved between adjacent attachments and adjacent components, thus producing good gap images. By using different foam materials in the different areas 3a, 3b of the foam layer 3, different surface requirements such as contour stability, contour accuracy, hardness, etc.

Claims

1. Method for selectively producing a first or a second variant of a multi-layered plastics component in the form of a trim part by means of one and the same foaming tool, wherein - the two variants each comprise a carrier part (1), a decorative layer (2; 4, 5) and a foam layer (3) between the carrier part and the decorative layer (2; 4, 5), - the foam layer (3) is produced in a foaming tool having a first tool half into which the carrier part (1) is inserted before the foaming operation, wherein to produce the first variant, prior to the foaming operation the decorative layer (2) of the first variant is inserted into a second tool half of the foaming tool and to produce the second variant, prior to the foaming operation a spacer layer (6) is inserted into the second tool half of the foaming tool, wherein the spacer layer (6) is removed from the foam layer (3) after the foaming operation and the decorative layer (4, 5) of the second variant is applied to the foam layer (3), characterized in that the foam layer (3) has at least one first portion (3a) which has a more stable contour than a second portion (3b) and in that a dimensionally stable foam material is used to create the first portion.

2. Method according to Claim 1, characterized in that the first region (3a) of the foam layer (3) has a higher hardness than the second region (3b) of the foam layer (3), wherein a hard foam material is used to create the first portion.

3. Method according to either of the preceding claims, characterized in that various materials are used to produce the regions (3a, 3b) of the foam layer (3).

4. Method according to either of the preceding claims, characterized in that polyurethane is used to produce the first region (3a) and to produce the second region (3b), with a distinction being made between the material characteristics of the polyurethane in the various regions.

5. Method according to one of the preceding claims, characterized in that the two variants have one and the same overall thickness (D).

6. Method according to one of the preceding claims, characterized in that the thickness of the decorative layer (2) of the first variant is smaller than the thickness of the decorative layer (4, 5) of the second variant and the thickness of the foam layer (3) of the first variant is greater than the thickness of the foam layer (3) of the second variant.

7. Method according to one of the preceding claims, characterized in that the spacer layer (6) is used to produce a multiplicity of second variants of the plastics component.

8. Method according to one of the preceding claims, characterized in that the decorative layer (2) of the first variant is a plastics skin.

9. Method according to one of the preceding claims, characterized in that the decorative layer (4, 5) of the second variant has a lower elastic layer (4) facing towards the foam layer (3) and an upper, imitation leather or genuine leather layer (5) connected to the elastic layer (4) or in that the decorative layer of the second variant is a single-ply layer made of imitation or natural leather.

10. Method according to one of the preceding claims, characterized in that the decorative layer (4, 5) of the second variant is adhesively bonded to the foam layer (3).