Method for manufacturing a sound-insulating cladding part and sound-insulating cladding part

Abstract

Method for manufacturing a sound-insulating cladding part (10) for a vehicle body part, comprising: Providing a base layer (12) with a specific geometry and Thickness dimension, and Back-foaming the base layer (12) with a foam material by placing the base layer (12) into a foaming tool so that a cavity is formed between the base layer (12) and the foaming tool, and by introducing a foam material reaction mixture (PUR) into the cavity so that a foam layer (14) of a certain thickness dimension is integrally formed onto the base layer (12) to produce the cladding part (12), characterized by the fact that a support layer (12) is provided which is surface micro-perforated on one of its surfaces facing away from the foam layer (14), and the foam layer (14) is formed directly adjacent to the base layer (12).

Description

[0001] The invention relates to a method for manufacturing a sound-insulating cladding part for a vehicle body part as defined in the preamble of claim 1 and to a sound-insulating cladding part for a vehicle body part as defined in the preamble of claim 8.

[0002] A method and a sound-insulating cladding component of the type mentioned above are known, for example, from DE 10 2007 020 832 A1. In the method and cladding component described therein, the supporting layer is formed from a porous and air-permeable absorber such as a nonwoven fabric or a foam. Between the foam layer, which is formed by back-foaming with a flexible polyurethane foam produced by means of a reaction mixture, and the supporting layer, a substantially airtight and pore-free skin is provided, which is produced from the reaction mixture under submerged pressure during the foaming process. The production of this lightweight cladding component thus requires a relatively complex process with regard to back-foaming the foam layer and the formation of the substantially airtight and pore-free skin, resulting in a relatively high manufacturing cost.

[0003] From DE 10 2004 012 937 A1, a method for producing a composite material with at least one decorative side having a textured or similar structure is known by back-injection or back-foaming of a film-like decorative material in a tool. Starting with an untextured, film-like material, this material receives a textured or similar surface structure in the same tool by being back-injected, back-foamed, or back-embossed.

[0004] DE 38 34 604 A1 describes a process for manufacturing molded parts from thermoformable plastic sheets using the negative drawing process. In this process, plastic sheets are placed in carousel-guided thermoforming molds and negatively drawn. Furthermore, a plastic foam reaction mixture is applied to the back of the plastic sheet in the thermoforming mold and foamed.

[0005] DE 19 25 634 A1 describes a process for manufacturing plastic products, resulting in a workpiece made of a laminated material or a composite material. Such processes are necessary when the surface of the substrate material does not meet the requirements for the workpiece with regard to color, smoothness, strength, or the like. In such a case, the substrate material must be coated with a laminating material.

[0006] From EP 2 819 122 B1, a sound-insulating body and an insulator for a motor vehicle are known. The sound-insulating body comprises a side layer formed from porous material, an intermediate layer layered on top of one side layer, and another side layer layered on top of the intermediate layer to face the first side layer through the intermediate layer. The intermediate layer is formed from a sound-absorbing layer of a membrane vibration type, which is formed from a non-air-permeable thin membrane layer of a flexible material. The other side layer is formed from a perforated sound-insulating layer formed from a sound-insulating material to include a plurality of opening sections in a distributed manner.

[0007] DE 100 22 902 A1 describes a cladding or molded element for means of transport, comprising at least one micro-perforated foil absorber, at least one foam and / or fleece absorber and / or air gap at a spatial distance from a sound-hard wall.

[0008] The invention is therefore based on the objective of providing a method for manufacturing a particularly lightweight sound-insulating cladding part for a vehicle body part, as defined in the preamble of claim 1, and a particularly lightweight sound-insulating cladding part for a vehicle body part, as defined in the preamble of claim 8, so that the manufacturing effort is reduced.

[0009] This is achieved with the features of claim 1 or the features of claim 8. Further developments of the invention are defined in the respective dependent claims.

[0010] According to the invention, a method (hereinafter referred to as the manufacturing method) for producing a particularly lightweight sound-insulating cladding part for a vehicle body part comprises at least the following process steps: providing a base layer with a specific geometry and a specific thickness dimension, and back-foaming the base layer with a foam material by placing the base layer into a foaming tool so that a cavity is formed between the base layer and the foaming tool, and introducing a foam material reaction mixture into the cavity so that a foam layer of a specific thickness dimension is integrally formed onto the base layer to produce the cladding part.

[0011] The inventive method is characterized in that an airtight foam film is provided as the back-foamable support layer, which is micro-perforated on one side of the surface facing away from the foam layer, and that the foam layer is molded directly adjacent to the support layer. In other words, a commercially available airtight, in particular non-porous or closed-cell, foam film is used as the support layer, and the non-porous or porous foam layer is molded directly onto the support layer without the need for another intermediate layer. This significantly simplifies the process of back-foaming the foam layer onto the support layer and thus reduces manufacturing costs.

[0012] According to the invention, the airtight support layer or foam film was micro-perforated on one side of the surface facing away from the foam layer before the specific geometry was realized (e.g., by deformation) in order to achieve an acoustic absorption effect. The support layer or foam film remains airtight as a whole even after micro-perforation.

[0013] Preferably, the foam material reaction mixture is formed by combining polyol and isocyanate in a mixing head with the addition of water, resulting in a chemical polyaddition reaction that produces carbon dioxide as a blowing agent and polyurethane foam with a density of preferably 50 g / l to 70 g / l. In other words, the foam layer is preferably a polyurethane foam layer. The support layer is preferably a polyethylene foam film or a polypropylene foam film with a basis weight of 500 g / m². 2 up to 1000 g / m²2 provided. Tests have shown that these materials are particularly well suited for use as an airtight foam film according to the invention.

[0014] According to one embodiment of the invention, the manufacturing process involves producing, for example, a front wall panel or front wall damping for a front wall (vehicle body part) separating the front compartment or engine compartment of a vehicle from a passenger compartment, as a sound-insulating paneling component. In other words, one embodiment of the invention provides a method for manufacturing a sound-insulating front wall panel or front wall damping for a vehicle's front wall.

[0015] Within the scope of the invention, it was also found that the manufacturing process according to the invention also has advantages over another process for manufacturing a sound-insulating cladding component for a vehicle body part. In this other manufacturing process, a heavy layer with a basis weight of 1700 g / m² is used as the base layer. 2 up to 8000 g / m² 2The base layer is preferably made of a thermoplastic elastomer (TPE) or ethylene propylene diene monomer (EPDM). In a foaming tool, which has an upper and lower part that, when closed, together with the base layer, form the cavity for introducing the foam material reaction mixture, such a base layer requires a relatively large gap (e.g., approximately 2 mm) in a sealing area located at the circumferential edge of the foaming tool that clamps the base layer. This sealing area also serves, in particular, to prevent the foam material reaction mixture from escaping the foaming tool.

[0016] If, as in a further embodiment of the invention, the support layer is provided with a thickness dimension slightly greater than the predetermined gap dimension of the foaming tool in the sealing area, an existing foaming tool designed for the production of a sound-insulating cladding component with a heavy layer can also be used to produce a lightweight sound-insulating cladding component using the manufacturing process according to the invention. This reduces the number of tool variants and the costs of tool production. Preferably, the support layer is provided with a thickness dimension of 1 mm to 3 mm, and in particular with a thickness dimension of 1.5 mm to 2.5 mm.

[0017] When carrying out the manufacturing process according to the invention using an existing foaming tool as mentioned above, the support layer designed as a foam film can be compressed to the predetermined gap dimension of the foaming tool in the sealing area when the upper and lower parts of the tool are brought together, thus reliably sealing the cavity against leakage of the foam material reaction mixture.

[0018] According to another embodiment of the invention, in the manufacturing process the base layer is provided such that one surface is covered with a top layer of plastic material. The base layer is introduced into the foaming tool in such a way that the top layer faces away from the cavity and thus from the foam material reaction mixture or the subsequent foam layer. The top layer can also provide a visible surface layer, which may have decorative elements such as a desired color, a texture, or similar features. The top layer can be made, for example, of PVC material or the like.

[0019] According to yet another embodiment of the invention, in the manufacturing process the support layer is prepared in such a way that, when heated to a predetermined forming temperature, it can be deformed into a desired three-dimensional shape and retains this three-dimensional shape after cooling. In other words, the support layer is thermally deformable and, in particular, deep-drawable. To prepare the support layer with the specific geometry, the support layer is heated to at least the forming temperature, then deformed into the desired three-dimensional shape in a forming tool, and preferably cooled below the forming temperature (by active cooling or by passive cooling over time) so that the support layer retains its three-dimensional shape.

[0020] To achieve the desired geometry, the base layer can also be subjected to a trimming process before and / or after heating to the deformation temperature and / or after obtaining the desired three-dimensional shape.

[0021] Preferably, the support layer, heated to at least the deformation temperature, is deformed into the desired three-dimensional shape in the forming tool by means of a deep-drawing process. A vacuum tool is preferably used to implement the deep-drawing process, which provides the desired three-dimensional shape within a tool topography. The tool topography includes suction holes through which the support layer, heated to the deformation temperature, can be drawn into the tool topography by means of a vacuum applied to the suction holes, thereby deforming it into the desired three-dimensional shape.

[0022] According to another embodiment of the invention, the forming of the support layer into the desired three-dimensional shape and the back-foaming of the support layer with the foam material or foam layer are carried out in a single tool, which incorporates both the forming tool and the foaming tool. This further reduces tooling complexity and tool variety. Preferably, the forming tool, such as a vacuum tool for a deep-drawing process, is formed by a lower part of the overall tool. The foaming tool is formed by the lower part and an upper part of the overall tool, with the lower and upper parts brought together and the cooled support layer, formed into the desired three-dimensional shape, conforming to the tool topography of the lower part.The cavity for introducing the foam material reaction mixture is then formed between a surface of the support layer facing away from the lower part of the tool and a tool topography of the upper part of the tool.

[0023] The invention also provides a particularly lightweight sound-insulating cladding component for a vehicle body part. The sound-insulating cladding component is manufactured in any of its aforementioned embodiments, particularly using the manufacturing process according to the invention. The sound-insulating cladding component comprises a base layer with a specific geometry and thickness, as well as a foam layer which is integrally molded onto the base layer on one surface side by back-foaming with a specific thickness. The sound-insulating cladding component according to the invention is characterized in that the base layer is designed as an airtight foam film and that the foam layer is directly adjacent to the base layer. In other words, the base layer is a commercially available airtight, particularly non-porous, or...A closed-cell foam film is used, and the non-porous or porous foam layer is directly molded onto the base layer without any intermediate layer. This significantly simplifies the process of back-foaming the foam layer onto the base layer and thus reduces the manufacturing effort for the cladding component.

[0024] According to the invention, the airtight support layer or foam film is micro-perforated on one side of the surface facing away from the foam layer before the specific geometry is realized (e.g., by deformation) in order to achieve an acoustic absorption effect. However, the support layer or foam film with the surface micro-perforation on the side facing away from the foam layer is also airtight as a whole.

[0025] Preferably, the foam layer is formed by reacting a foam material reaction mixture. The foam material reaction mixture is preferably formed by combining polyol and isocyanate in a mixing head with the addition of water, such that carbon dioxide is produced as a blowing agent and polyurethane foam with a density of preferably 50 g / l to 70 g / l in a chemical polyaddition reaction. In other words, the foam layer is preferably formed as a polyurethane foam layer.

[0026] The base layer is preferably made of polyethylene foam film or polypropylene foam film with a basis weight of 500 g / m². 2 up to 1000 g / m² 2 The base layer is preferably designed with a thickness dimension of 1 mm to 3 mm, in particular a thickness dimension of 1.5 mm to 2.5 mm.

[0027] According to one embodiment of the invention, the sound-insulating cladding part is designed as a sound-insulating front wall cladding or front wall damping for a vehicle front wall.

[0028] According to another embodiment of the invention, the base layer has a top layer made of plastic material on a surface facing away from the foam layer. The top layer preferably provides a visible surface which may have decorative elements such as a desired color, a texture, or the like. Preferably, the top layer is made of PVC material or the like and is preferably laminated onto the surface of the base layer.

[0029] According to a further embodiment of the invention, the support layer can be deformed into a desired three-dimensional shape when heated to a predetermined deformation temperature and retains this three-dimensional shape after cooling. In other words, the support layer is thermally deformable and, in particular, deep-drawable.

[0030] According to yet another embodiment of the invention, the specific geometry of the support layer is formed by heating the support layer to the deformation temperature, deforming the support layer heated to the deformation temperature in a forming tool into the desired three-dimensional shape, and cooling the support layer deformed into the desired three-dimensional shape below the deformation temperature (by active cooling or by passive cooling over time), so that the support layer retains the three-dimensional shape.

[0031] To achieve the desired geometry, the base layer may also have been subjected to a trimming process before and / or after heating to the deformation temperature and / or after obtaining the desired three-dimensional shape.

[0032] Preferably, the support layer, heated to the deformation temperature, was deformed into the desired three-dimensional shape in the forming tool using a deep-drawing process. A vacuum tool, which has the desired three-dimensional shape in its tool topography, was preferably used to carry out the deep-drawing process. The tool topography contains suction holes through which the support layer, heated to the deformation temperature, was forced into contact with the tool topography by means of a vacuum applied to the suction holes, thereby deforming it into the desired three-dimensional shape.

[0033] According to the invention, a tool for manufacturing the sound-insulating cladding component according to the invention is designed as a single, integrated tool that functions both as a forming tool for shaping the support layer into the desired three-dimensional form and as a foaming tool for back-foaming the support layer with the foam material or foam layer. This further reduces the tooling complexity and the number of tools required. According to the invention, a separate pre-forming tool is also possible in a step preceding the foaming process.

[0034] Preferably, the forming tool is a vacuum tool, as described above, for realizing a deep-drawing process, formed by a lower tool section of the overall tool. The foaming tool is formed by the lower tool section and an upper tool section of the overall tool, wherein the lower and upper tool sections are brought together and the support layer, deformed to the desired three-dimensional shape, conforms to the tool topography of the lower tool section. The cavity for introducing the foam material reaction mixture is then formed between a surface of the support layer facing away from the lower tool section and a tool topography of the upper tool section.

[0035] The invention expressly extends to embodiments which are not given by combinations of features from explicit cross-references of the claims, whereby the disclosed features of the invention can be combined arbitrarily with one another - insofar as this is technically sensible.

[0036] The invention will now be described with reference to preferred embodiments and the accompanying figure. Fig. Figure 1 shows a schematic sectional view of an overall tool for manufacturing a sound-insulating cladding part for a vehicle body part according to the invention.

[0037] The following will refer to Fig. 1 a sound-insulating cladding part 10 for a vehicle body part of a motor vehicle (neither of the latter being shown) and a method (hereinafter referred to as the manufacturing method) for manufacturing the sound-insulating cladding part 10 according to embodiments of the invention are described.

[0038] The trim panel 10 is designed as a bulkhead trim or bulkhead damping for the bulkhead (vehicle body part) separating the front compartment or engine compartment of the motor vehicle from the passenger compartment. When installed, the trim panel 10 rests against the bulkhead, which is made of sheet metal, to insulate the passenger compartment from noise emanating from the engine compartment.

[0039] The cladding part 10 is designed as a lightweight component and has a support layer 12 with a specific geometry and a specific thickness dimension, as well as a porous or non-porous foam layer 14, which is integrally molded onto the support layer 12 by back-foaming with a specific thickness dimension (e.g., approximately 10 mm to 20 mm) on one surface side of the support layer 12, directly adjacent to the support layer 12, so that the support layer 12 and the foam layer 14 are fully and irreversibly connected to each other.

[0040] The base layer 12 is designed as a commercially available, airtight, and in particular non-porous or closed-cell, foam film which, when heated to a predetermined deformation temperature, can be deformed into a desired, in particular three-dimensional, shape and retains this shape after cooling. In other words, the base layer 12 is thermally deformable and, in particular, deep-drawable. The base layer 12 is preferably made of polyethylene foam film or polypropylene foam film with a basis weight of 500 g / m². 2 up to 1000 g / m² 2 The film-shaped support layer 12 preferably has a thickness in the range of 1 mm to 3 mm, particularly in the range of 1.5 mm to 2.5 mm. The foam layer 14 is designed as a polyurethane foam layer.

[0041] In an embodiment of the invention not shown, the support layer 12 can have a top layer made of plastic material on a surface facing away from the foam layer 14. The top layer preferably provides a visible surface which can have decorative elements such as a desired color, a texture, or the like. Preferably, the top layer is made of PVC material or the like and is preferably laminated onto the surface of the support layer 12 facing away from the foam layer 14.

[0042] The specific geometry of the support layer 12 is formed by heating the support layer 12 to the deformation temperature, deforming the support layer 12 heated to the deformation temperature in a forming tool by means of a deep-drawing process to the desired three-dimensional shape, and preferably cooling the support layer 12 deformed to the desired three-dimensional shape below the deformation temperature (by active cooling or by passive cooling over time), so that the support layer 12 has retained the three-dimensional shape.

[0043] To achieve the desired geometry, the base layer 12 may also have been subjected to a trimming process before and / or after heating to the deformation temperature and / or after obtaining the desired three-dimensional shape.

[0044] In the manufacturing process for producing the sound-insulating cladding part 10, at least the following process steps are carried out: providing the base layer 12 (air-impermeable foam film) with the specified geometry and thickness dimension, and back-foaming the base layer 12 with a foam material by placing the back-foamable base layer 12 into a foaming tool, so that a cavity is formed between the base layer 12 and the foaming tool, and introducing a foam material reaction mixture PUR into the cavity of the foaming tool, so that the foam layer 14 with the specified thickness dimension is integrally molded directly adjacent to the base layer 12 in order to produce the cladding part 10.

[0045] As from Fig. As can be seen in Figure 1, the cladding part 10 is manufactured in a complete tool 1, which is designed to function both as a forming tool for shaping the support layer 12 into the desired three-dimensional form and as a foaming tool for back-foaming the support layer 12 with the foam material or foam layer 14. For this purpose, the complete tool 1 has a lower tool part 3 and an upper tool part 5, which can be moved together (as shown in Figure 1). Fig. 1 shown) and are retractable, as indicated by the double arrow in Fig. 1 indicated.

[0046] The forming tool is formed by the lower tool section 3 of the overall tool 1. To produce the support layer 12 with the specified geometry, it is first heated to the forming temperature as a foil blank in a separate lower tool (not shown). The support layer 12, heated to the forming temperature, is then deformed into the desired three-dimensional shape in the forming tool, or on the lower tool section 3, by means of a deep-drawing process. To realize the deep-drawing process, the lower tool section 3 is designed as a vacuum tool, which provides the desired three-dimensional shape within a tool topography of the lower tool section 3. The lower tool section 3 contains intake channels 4 that open into intake holes (not labeled) in the tool topography of the lower tool section 3.The support layer 12, heated to the deformation temperature, is forced through the intake holes by means of a vacuum V applied to the intake channels 4 and thus to the intake holes, conforming to the tool topography of the lower tool part 3 and thereby deforming it into the desired three-dimensional shape. Subsequently, the support layer, now deformed into the desired three-dimensional shape, is preferably cooled below the deformation temperature (by active cooling or by passive cooling over time), so that the support layer 12 retains its three-dimensional shape.

[0047] To achieve the specific geometry of the base layer 12, it is also subjected to a trimming process before and / or after heating to the deformation temperature and / or after obtaining the desired three-dimensional shape.

[0048] After the support layer 12 has been given the specified three-dimensional geometry, it is back-foamed in the foaming tool. The foaming tool is formed by the lower tool part 3 and the upper tool part 5 of the overall tool 1, whereby for back-foaming the lower tool part 3 and the upper tool part 5 are brought together and the support layer 12, having the specified geometry, is conformed to the tool topography of the lower tool part 3 by means of a vacuum V, completely covering the suction holes.

[0049] The cavity for introducing the foam material reaction mixture PUR is then formed between a surface side of the support layer 12 facing away from the lower part of the tool 3 and a tool topography of the upper part of the tool 5.

[0050] If the base layer 12 is provided with the top layer made of plastic material on one surface side, the base layer 12 is positioned in the foaming tool or on the tool base 3 in such a way that the top layer is facing away from the cavity and thus away from the foam material reaction mixture PUR or the subsequent foam layer 14 or towards the tool topography of the tool base 3.

[0051] When the lower tool part 3 and the upper tool part 5 are closed, they have a gap S of, for example, approximately 2 mm in a sealing area located at the circumferential edge of the overall tool 1, which clamps the support layer 12. This sealing area serves in particular to prevent the foam material reaction mixture PUR from escaping from the overall tool 1.

[0052] The support layer 12 is therefore provided with a thickness dimension (e.g., approximately 2.5 mm) that is slightly larger than the specified gap dimension S of the overall tool 1 in the sealing area. When the upper tool part 5 and the lower tool part 3 are brought together, the support layer 12 is compressed in the sealing area to the specified gap dimension S of the overall tool 1 and thus reliably seals the cavity against the escape of the PUR foam material reaction mixture.

[0053] The PUR foam material reaction mixture is preferably formed by combining polyol and isocyanate in a mixing head (not shown) with the addition of water, resulting in a chemical polyaddition reaction that produces carbon dioxide as a blowing agent and polyurethane foam with a density of preferably 50 g / l to 70 g / l. The PUR foam material reaction mixture is introduced from the mixing head into the cavity of the closed overall tool 1 via a feed channel 6, which extends through the upper part of the tool 5 and is open towards the topography of the upper part of the tool 5.

[0054] After the PUR foam material reaction mixture has reacted and hardened, the upper tool part 5 and the lower tool part 3 are separated again so that the cladding part 10 can be removed from the overall tool 1. Finally, the cladding part 10 can be subjected to a final cutting process, e.g., in a separate cutting tool (not shown), for trimming and / or punching holes. Reference symbol list 1 complete tool 3 Tool base 4 intake ports 5 Tool top 6 Feed channel 10. Trim part 12 Base course 14 foam layer PUR foam material reaction mixture S gap dimension V Vacuum application

Claims

A method for producing a sound-insulating cladding part (10) for a vehicle body part, comprising: providing a base layer (12) with a specific geometry and thickness dimension, and back-foaming the base layer (12) with a foam material by introducing the base layer (12) into a foaming tool, such that a cavity is formed between the base layer (12) and the foaming tool, and introducing a foam material reaction mixture (PUR) into the cavity, so that a foam layer (14) of a specific thickness dimension is integrally formed onto the base layer (12) to produce the cladding part (12), characterized in that an airtight foam film is provided as the base layer (12), which is micro-perforated on one surface side facing away from the foam layer (14), and the foam layer (14) is formed directly adjacent to the base layer (12). Method according to claim 1, wherein the support layer (12) is provided as polyethylene foam film or as polypropylene foam film. Method according to claim 1 or 2, wherein the support layer (12) is provided such that it is provided on one surface side with a cover layer of plastic material, and wherein the support layer (12) is introduced into the foaming tool such that the cover layer faces away from the cavity. Method according to one of claims 1-3, wherein the support layer (12) is provided with a thickness dimension of 1 mm to 3 mm. A method according to any one of claims 1-4, wherein the support layer (12) is provided such that it is deformable to a desired three-dimensional shape when heated to a predetermined deformation temperature and retains the three-dimensional shape after cooling, and wherein, in order to provide the support layer (12) with the determined geometry, the support layer (12) is heated at least to the deformation temperature, the heated support layer (12) is deformed to the desired three-dimensional shape in a forming tool, and the deformed support layer (12) is cooled below the deformation temperature so that the support layer (12) retains the three-dimensional shape. Method according to claim 5, wherein the support layer (12) heated to at least the deformation temperature is deformed in the forming tool to the desired three-dimensional shape by means of a deep drawing process. Method according to claim 5 or 6, wherein the deformation of the support layer (12) to the desired three-dimensional shape and the back-foaming of the support layer (12) with the foam material are carried out in a complete tool (1) which realizes both the forming tool and the foaming tool. Sound-insulating cladding part (10) for a vehicle body part, comprising: a support layer (12) with a specific geometry and thickness dimension, and a foam layer (14) which is integrally formed on one surface side of the support layer (12) by back-foaming with a specific thickness dimension, characterized in that the support layer (12) is designed as an airtight foam film which is micro-perforated on one surface side facing away from the foam layer (14) and that the foam layer (14) is directly adjacent to the support layer (12). Sound-insulating cladding part (10) according to claim 8, wherein the support layer (12) is designed as polyethylene foam film or as polypropylene foam film. Sound-insulating cladding part (10) according to claim 8 or 9, wherein the thickness dimension of the support layer (12) is from 1 mm to 3 mm.

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