MXPA00008055A - Flat composite body,especially a motor vehicle body element - Google Patents

Abstract

The invention relates to a flat composite body (12) with an asymmetric layer construction comprised of a first layer (13) made of a metallic material, an intermediate layer (17), and a second layer (15) made of a non-metallic material. A non-woven material (14) is placed between the first layer (13) and the intermediate layer (17), and a fiber mat (16) is placed between the intermediate layer (17) and the second layer (15). Both the non-woven material (14) and the fiber mat (16) are provided with an epoxide resin bonding substance. The inventive flat composite body (12) having a low weight exhibits a high dimensional stability and rigidity and additionally comprises a good paintability.

Description

COMPOSITE FLAT BODY, IN PARTICULAR BODY ELEMENT FOR AUTOMOBILE VEHICLE Description of the invention The invention relates to a flat composite body as an element of a motor vehicle body, with an asymmetric layer structure comprising a first outer layer of a car body material. aluminum, a sheet of steel or a sintered metal, further comprising an intermediate layer, in particular a core of spongy material, and a second inner layer of a non-metallic material. The invention also relates to a method for manufacturing a flat composite body of this nature. A composite body of the type under consideration and a method for its manufacture were disclosed through the dissertation "Considerations regarding the application of sandwich-type components in mass production, their sizing and design based on the example of the engine hood of the AUDI test car "from the series of treaties Statusberichte des BMFT - Entwicklungslinien für Kraftfahrzeuge und Kraftstoffe - Forschungsbilanz 1982, Seiten 167 bis 177, Verlag TÜV Rheinland "(Progress Reports of the BMFT - Trends in the Development of Vehicles and Fuels -, research balance 1982, pages 167 to 177, Editorial TÜV Rheinland). The dissertation deals with the light construction of the sandwich structure based on the example of a motor hood for motor vehicles. Sizing, design and manufacturing considerations show the possibilities and limits of this principle of light construction. On pages 171 and 172 various embodiments are illustrated with respect to the structure of the layers. In one of the embodiments, the layers of the cover consist of aluminum or coated metal sheet and plastic. By this, an asymmetric structure of the layers is obtained. The core preferably consists of Structano (thermoreactive plastic, foamed, reinforced with fiberglass of variable cubic weight). The material - Structano - assumes in this the function of compensating the tension (prevention against deformation). DE 39 39 534 C2 describes a process and a seat mold for the manufacture of plates and objects in the form of plates, such as doors, in particular doors for refrigerators. Also in this case an asymmetric structure of the layers is realized, specifically by means of a cover layer of metal sheet on one side and a cover layer of plastic sheet on the other side, and between these a core of spongy solid foam in situ from a liquid reactive mixture. The aim is to counteract the risk of deformation due to the different coefficients of thermal expansion by subjecting the metal cover layer and / or the plastic sheet cover layer to a pre-deformation that compensates for the deformation that appears before the filling foam. during cooling, directed against the latter. The deformation that appears can not be calculated and it is necessary to determine it empirically. For greater integrity, we further refer to WO 83/00840 A which describes a composite body, in particular a composite plate for the construction of boat walls / boats, container walls or the like comprising a rigid external envelope on both sides, a foam filling body composed of one or several parts, and intermediate layers of fiberglass or the like reinforced with fibers between each outer shell and the filling body, as well as hardened plastic to bind the entire arrangement. Here results a symmetrical structure in which each outer shell is constituted by a material with a resistance to pressure approximated to that of pure aluminum. From this the invention is based on the task of providing a flat composite body as a vehicle body element with an asymmetric layer structure, which with low weight has a high dimensional stability and high strength as well as good characteristics for accepting paint . The solution according to the invention is found in a flat composite body of asymmetric structure having the characteristics of patent claim 1.

Claim 7 of the patent reproduces a method especially suitable for its manufacture. The advantageous designs and improvements of the invention are claimed with the respective subordinate claims. The invention is explained in more detail on the basis of an exemplary embodiment for an asymmetrical flat composite body of this nature, whereby a particularly suitable application case is here a freestanding body part for a passenger motor vehicle, such as for example a solid awning. In the drawing show: Figure 1 a passenger motor vehicle without solid awning, Figure 2 the same vehicle with the solid awning placed, Figure 3 the solid awning only, and Figure 4 a sectional representation of the solid awning according to arrows IV of figure 3.

Figure 1 shows in section a vehicle 1 passenger car with door 2 of the trunk, rear fenders 3,4 rear left and right, doors 5,6 left and right of the vehicle, and frame 7 for a windshield. A passenger cabin 8 is open at the top, analogously to a convertible. On the edges of the door 2 of the trunk and of the rear fenders 3 facing the passenger cabin 8 a surrounding mechanism 9 for accommodation and fixing is provided. An analogous mounting and locking mechanism 10 extends along the horizontally aligned upper section of the frame 7. Both housing and fixing mechanisms 9, 10 serve to house a solid awning 12 as shown in Figure 2, so that now the passenger cabin 8 can be closed above. That is, the solid awning 12 can be assembled or disassembled as necessary, so that the passenger car vehicle 1 can be operated in a correspondingly equipped manner. For clarity Figure 3 again shows the solid awning 12 in an independent representation, while the layered structure of this asymmetric flat composite body is derived from Figure 4. In this the outer layer 13 is formed by a preformed plate. of an aluminum material, in which case a steel plate or a sintered metal could also be used. Adjacent to this outer layer 13 is a non-woven material 14 of polyester provided with an expandable epoxy resin binder. An interior layer 15 on the side of the passenger cabin is formed by a decorative fabric having adjoining a fiber mat 16, also provided with an expandable epoxy resin binder. The hollow space is filled with a spongy polyurethane (PU) core 17, a spongy EPS core, other light foams (polypropylene, etc.) or a glass core blown with a binder would also be imaginable. In suitable places within the hollow space intermediate layers 18 can be provided, for example likewise of an aluminum material, which are connected for example by means of screwed connection 19 to the outer or inner layer 13, 15.; Accordingly, the flat composite body-solid structure 12 according to the embodiment example-is preferably constituted by a metallic surface, a non-woven polyester material, which can absolutely be a commercially available product as described above. uses, for example, in kitchen tile filters, a medium density foam core (approximately 20 kg / m3 to approximately 100 kg / m3), a fiber mat (glass entanglement mesh that preferably has a suitable finish for epoxy resins) , which optionally contains a thermoplastic binder for thermal deformation) and a decorative multilayer film, preferably with a PUR barrier layer. As a decorative sheet, in particular thermoplastic sheets with integrated barrier layer (it is necessary to prevent penetration of the foam during the pressing connection), but also natural products such as leather, for example, if it resists a foam pressure of approximately 1.5 bar without being penetrated. The polyester non-woven material and the cut fiber mat are also wetted with an expandable epoxy resin. Individually, the following layer structure is given: aluminum sheet (alkaline defatted); thickness of the sheet 1.1 mm polyester non-woven fabric 300 g / m2 PU foam core with RG of approximately 54 kg / m3 (RG = cubic weight) cut glass fiber mat: 450 g / m2 polyurethane decorative fabric: blocking sheet 70 μm, being an expandable matrix system with a mass of reactive resin (total amount of resin + hardener + diffusing agent) of 1600 g / m2 (external) and approximately 1300 g / m2 (internal) that serves as a binder is defined furthermore as follows: Araldit® resin LY 5054 (trade name Ciba Spezialitátenchemie AG, Basel) + 1% diffusing agent, Hardener XB 5003-1® (trade name Ciba Spezialitátenchemie AG, Basel), DY 5054® diffusing agent (trade name Ciba Spezialitatenchemie AG, Basel), Proportion of the mixture: 100: 20 parts by weight, being that the mass of reactive resin can be expanded and the resulting foam does not collapse under the application of the separating agent based on PAT® 921 / A the Würtz corporate name. As an expandable matrix system serving as a binder, all liquid epoxy resin systems which can react with a hardener / hardener mixture are suitable in principle. Bisphenolic epoxy resins are preferred for this purpose, for example epoxides Bisphenol-A and Bisphenol-A / F, modified with stabilizers and thixotropic agents. Also suitable are glycidyl ethers of aliphatic alcohols or polyalkylene glycols, in addition also solid epoxy resins which can be prepared in liquid form when mixed with a liquid epoxy resin, as epoxy resins can be used, for example, epoxy resins Bisphenol-A. As a hardener, it is possible in principle to use all known liquid hardeners, for example aliphatic, cycloaliphatic amines as well as their educts, for example with epoxides, and also polyamidoamines. Depending on the system of the epoxy resin, other additives promoting hardening, for example tertiary amines, can also be used. The non-woven material to be used according to the invention thus serves as counter-traction and compensates for the stresses that appear due to the asymmetry. For this reason the non-woven material must contract during the hardening process. Examples of the non-woven materials are the thermoplastic non-woven materials, with non-woven materials based on thermoplastic polyesters being preferred. In principle it is possible to use all conventional fibers such as glass, coal, Kevlar and natural fibers. The cut glass fibers have the advantage that they can be well penetrated by the foam. In principle it is possible to use all fabrics and fiberglass complexes. In the manufacture of the composite body according to the invention (solid awning 12), the procedure is as follows: First, the external layer 13 is molded by means of a suitable deep-drawing tool, ie, for example, an aluminum plate according to the invention. to the shape that will later have the solid awning 12, and then the contours of the edge are cut (for example by laser cutting). Following this, the preformed embedded part is subjected to an alkaline defatting of its surface to improve adhesion. The alkaline degreasing preferably consists of the defatting stages - washing - biting passivation - washing - drying. This could be followed, in addition to a corrosion protection coating, for example a zinc phosphating, a cataphoretic bottom layer, possibly by the immersion method (KTL). The PU foam core 17 provided between the inner and outer layers 13, 15 is sponged in a suitable tool before joining and joining the individual layers of the composite body. The preformed piece of foam is then wrapped with the fiber mat 16 and the non-woven material 14, and is moistened with an expandable epoxy resin. To join the individual layers and thus produce the solid awning 12 in a single operation the external layer 13 preformed in the tool die is placed using a suitable press tool, the inner layer 15 (decorative layer) is expanded over the die the tool and the foam core 17 is likewise placed in the tool die in front of the outer layer 13. ThenBy means of a corresponding movement of the die, the closing of the mold of the tool is carried out with the consequent pressing connection of the individual layers with simultaneous hardening. By virtue of the proportions of expansion of the individual layers being adjusted with respect to one another, a composite body of stable dimensions is obtained. With the use of the epoxy resin, the stability of the form is achieved mainly because there is no contraction due to expansion in the liquid phase, except for the insignificant shrinkage due to cooling. The sparkling system must retain its volume until the beginning of gelation. In the tests it was found convenient that the pressing tools have a temperature of about 40 to 50 ° C when the individual components of the flat composite body are pressed together. Good results were achieved with a pressing time of approximately 60 minutes. Other temperatures and pressing times are imaginable. It must be possible to adjust the tools to press accordingly. As a result, a flat composite body is obtained which has the advantages already mentioned and which also has good properties when painting the metal surface (outer layer 13). During the manufacturing process it is also possible to fit in the hollow space that is subsequently filled by the PU foam core, empty tubes for a later wiring. It is also possible to install fasteners such as screwed plates or inserted elements. The invention is also not limited to the application case (solid awning) shown in the exemplary embodiment. Its application for other parts of the vehicle is also conceivable, even in the case of vehicles on rails as well as for decorative design elements, elements of spherical facades, elements for the assembly of fairs and the like. The present method can be applied in particular in all those cases in which a metal surface is required and a low weight of the component is desirable. Examples are: construction of machines (mobile masses), construction of boats / boats, aerial vehicles, sports equipment, interior decoration, panels, facades, furniture, etc.

Claims (9)

1. Flat composite body as an element of a motor vehicle body, with an asymmetric layer structure comprising a first outer layer of a material, of aluminum, a sheet of steel or a sintered metal, further comprising an intermediate layer, in particular a spongy material core, and a second inner layer of a non-metallic material, characterized in that a non-woven material provided with an epoxy resin binder, and between the intermediate layer and the intermediate layer, is disposed between the first outer layer and the intermediate layer. the second inner layer a fiber mat provided with an epoxy resin binder

2. A composite body according to claim 1, characterized by the use of an aluminum plate as the first layer, a non-woven polyester material, a core of polyurethane foam. of an average density between about 20 kg / m3 and about 100 kg / m3 as an intermediate layer, and further characterized by the use of a fibrous mat cut glass and a multilayer decorative sheet with barrier layer that serves as the second 'inner layer.

3. Composite body according to claim 1, characterized by the following layer structure: Metal sheet of alkaline-defatted aluminum, optionally with anticorrosive coating and KTL; Thickness of the sheet in the range of 1 mm; Non-woven polyester fabric of 300 g / m2, Viledon® 15/500 S; Kapex® polyurethane foam core of the company name Airex / CH, with a cubic weight of approximately 54 kg / m3; Mat of cut glass fibers: 450 g / m2 Decorative polyurethane fabric: barrier film - 70 μm; being that an expandable matrix system with a mass of reactive resin with a total amount of resin + hardener + diffusing agent of 1600 g / m2 for the exterior and approximately 1300 g / m2 for the interior, which serves as a binder, is further defined as follows: Araldit® LY 5054 resin from Ciba Spezialitátenchemie AG, Basilea + 1% diffusing agent, Hardener XB 5003-1® from Ciba Spezialitátenchemie AG, Basel, DY 5054® Diffusing agent from Ciba Spezialitátenchemie AG, Basel, Proportion of the mixture: 100: 20 parts by weight; being that the reactive resin mass can be expanded and the resulting foam does not collapse with the application of the base release agent of PAT® 921 / A of the Würtz trade name.

4. Composite body according to claim 2 or 3, characterized by the alternative use of an EPS or PP foam core, or of glass insufflated with a binder as an intermediate layer. Composite body according to claim 1, characterized in that additional elements such as empty tubes, reinforcements or the like, are connected to the outer or inner layer in the hollow space filling the intermediate layer. Method for manufacturing a flat composite body as an element of a motor vehicle body, with an asymmetric layer structure comprising a first outer layer of an aluminum material, a steel sheet or a sintered metal, further comprising a layer intermediate, in particular a core of spongy material, and further comprising a second inner layer of a non-metallic material, according to claim 1, characterized by the steps of preforming and trimming the first layer, - fluffing the intermediate layer, wrapping the layer intermediate sponge with fiber mat and non-woven material, followed by wetting with an expandable epoxy resin, placing or associating the first and second layers to a tool die or die of the tool, placing the sponge intermediate layer on the machine tool followed by pressing together the individual layers with simultaneous hardening. Method according to claim 6, characterized in that the surface of the first layer is subjected to an alkaline degreasing after its pre-forming. Method according to claim 7, characterized in that the alkaline degreasing comprises the steps of degreasing-washing-mordant passivation-washing-drying. Method according to claim 6, characterized in that the temperature during the pressing is approximately 40 to 50 ° C and that the pressing time is approximately 60 minutes.