Method of making a flat building component

Abstract

The invention relates to a method of making a thin construction element (10) in sandwich lightweight construction having a high-quality surface (26). Including the steps of deep drawing a substrate film, placing the deep-drawn film into a cavity of a die, introducing partially expanded particles onto the substrate, heating to completely expanded the particle foam, curing the expanded particle foam, and opening the die to remove the molded article.

Claims

1. A method of making a thin construction element in sandwich lightweight construction and having a high-quality surface, the method comprising the following steps: a) providing a substrate film of PMMA or ABS having a thickness between 0.2 mm and 13 mm, b) deep-drawing the substrate film and placing the deep-drawn film into a cavity of a lower die part of a die such that bottom and side walls of the cavity are covered by the substrate film, c) providing granular starting material in the form of loose particles of an expandable particle foam, d) only partly expanding the particles outside the die, e) introducing the partly expanded particles into a the cavity of the lower die part on top of the deep-drawn substrate film in the cavity and fitting an upper die part to the lower die part to close the cavity on all sides, h) heating the lower part of the closed die with a heating device to a predetermined temperature with the cavity closed on all sides to conduct heat from the lower part through the substrate film to the partly expanded particles and thereby further expand the partly expanded particles into a completely expanded particle foam that bonds to the substrate film, i) curing the completely expanded particle foam in the closed die into a molded article, and j) opening the closed die and removing the molded article from the cavity of the die.

2. The method according to claim 1, further comprising the step of: k) after step c and before closing the cavity, applying a cover layer on a side of the partly expanded particles facing away from the substrate film.

3. The method according to claim 1, further comprising the step of: l) processing the molded article into a construction element.

4. The method according to claim 1, wherein the cured-particle foam has a wall thickness between 1 cm and 30 cm.

5. The method according to claim 1, wherein the construction element is configured as a vehicle part for a motor vehicle, a commercial vehicle, or a trailer, like an interior fitting part, cargo compartment cover, cladding part, engine hood, roof element or roof segment, vehicle wall, or vehicle wall element.

6. The method according to claim 1, wherein the expandable particle foam is of expandable polystyrene, polypropylene, or polyether ether ketone.

7. The method according to claim 1, wherein before step h) , the following step is performed: m) positioning reinforcing elements as tie rods in the lower die part such that after the introduction of the partly expanded particles into the lower die part, the partly expanded particles surround the reinforcing elements.

8. A method of making a thin construction element in sandwich lightweight construction and having a high-quality surface, the method comprising the following steps: a) providing a substrate film of PMMA or ABS having a thickness between 0.2 mm and 13 mm, b) deep-drawing the substrate film and placing the deep-drawn film into a cavity of a lower die part of a die with the substrate film such that a bottom wall and side walls of the lower die part are covered by the substrate film, c) providing granular starting material in the form of loose particles of an expandable particle foam, d) only partly expanding the particles outside the die, e) introducing the partly expanded particles into the cavity of the lower die part on top of the deep-drawn substrate film, h) heating parts of the die with the cavity being closed on all sides with a heating device to a predetermined temperature to further expand the partly expanded particles into a completely expanded particle foam that bonds to the substrate film, the further expansion of the partly expanded particles being triggered by the predetermined temperature of the die, i) curing the completely expanded particle foam to cure in the die into a molded article, and j) opening the die and removing the molded article from the cavity of the die.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a partly sectioned schematic view, an embodiment of an oven in which unexpanded granular starting material is poured in the form of particles of a particle foam,

(2) FIG. 2 shows the oven of FIG. 1 with an additionally illustrated infrared radiant heater for converting the previously poured-in particles into a partly expanded state,

(3) FIG. 3 shows a first die having lower and upper die parts and a film formed as a flat web substrate,

(4) FIG. 4 shows the closed die of FIG. 3 with a deep-drawn film,

(5) FIG. 5 shows a further lower die part holding the deep-drawn film of FIG. 4, the partly expanded particles of the particle foam according to FIG. 2 being poured into the lower die part,

(6) FIG. 6 shows the die of FIG. 5 with an also illustrated upper die part shown just before the die is completely closed,

(7) FIG. 7 shows the die of FIG. 6 in the fully closed state with a heating device for the die also illustrated,

(8) FIG. 8 shows the die of FIG. 7 in the open state with a finally expanded cured-particle foam mass,

(9) FIG. 9 shows the molded article removed from the die of FIG. 8 with separation lines along which projecting regions of the substrate are separated,

(10) FIG. 10 shows a further embodiment of a molded article or a construction element according to the invention formed by the method according to the invention and having an additional layer on the side of the cured-particle foam mass facing away from the substrate, and

(11) FIG. 11 shows a further embodiment of a construction element according to the invention in a representation according to FIG. 10 but where the pore structure of the cured-particle foam is illustrated in a modified manner with respect to FIG. 10 only for purposes of illustration.

DETAILED DESCRIPTION OF THE INVENTION

(12) Embodiments of the invention are described by way of example in the following description of the figures, also with reference to the drawings. For reasons of clarity, identical or comparable parts or elements or regions are also referred to with the same reference numerals, sometimes with the addition of small letters, even if different embodiments are involved.

(13) Features that are described, illustrated or disclosed only in relation to an embodiment can be provided within the scope of the invention in any other embodiment of the invention. Such modified embodiments are comprised by the invention, even if they are not illustrated in the drawings.

(14) All disclosed features are essential to the invention. In the disclosure of the application, the disclosure content of the associated priority documents (copy of the prior application) and the cited documents and the described devices of the prior art are hereby incorporated in full content, also for the purpose of one or more features of the objects disclosed therein or in several claims of the present application. The invention also comprises such modified embodiments, even if they are not illustrated in the drawings.

(15) Embodiments of construction elements that have been manufactured according to the method according to the invention are denoted by 10 in their entirety in FIGS. 8, 9, 10 and 11.

(16) The method for manufacturing such a construction element 10 will be presented in the following, starting from FIG. 1:

(17) As shown in FIG. 1, a container 12 is shown, into which a granulate 11 of a particle foam is poured. The individual granulate particles, which are designated by the reference numerals 30a, 30b, 30c by way of example, are unexpanded, and constitute the starting material for manufacturing a particle foam. The individual materials that can be used according to the method of the invention are specified in detail later.

(18) As shown in FIG. 2, the container 12 is part of an oven 13, in which the granulate particles 30a, 30b, 30c can be partly expanded:

(19) A heater 14, in particular an infrared heater 14, is provided for this purpose, which introduces a predetermined radiant power using infrared radiation 15 (indicated) into the oven 13 in order to reach a certain temperature or a certain temperature range. The granulate particles 30a, 30b, 30c are exposed in the oven 13 to the influence of temperature for a predetermined time and partly expanded. It can be seen that the individual particles 30a, 30b, 30c of FIG. 1 gain considerably in volume and, according to FIG. 2, mutate into partly expanded particles 31a, 31b, 31c.

(20) It should be noted that the figures are of course not to scale, but that the process of expanding and the volume enlargements are to be illustrated only by way of example.

(21) The partly expanded particles 31a, 31b, 31c are still loose, in particular, not bonded with one another. During the process of only partly expanding according to FIG. 2, additional measures, such as shaking the container 12, stirring, use of chemicals, or introduction of chemicals into the container 12, etc., can be achieved so that the particles 31a, 31b, 31c do not bond with each other or predominantly do not bond with each other, but are still transportable as a loose, free-flowing or at least pourable mass. As shown in FIG. 5, this mass is poured into a lower die part 23 of a die 17b.

(22) First, with reference to FIGS. 3 to 4, the production of substrates 21 are explained:

(23) As shown in FIG. 3, a first die 17 is provided that comprises an upper die part 18 and a lower die part 19. The relevant die parts can be configured in the manner of a die and in the manner of a male mold. In FIG. 3, a film 20 in flat-lying, web-shaped state, that is, an initial state, can be seen. FIG. 3 shows the die in the open state.

(24) As a result of closing the die, the film 20 is deep-drawn from the flat-lying state. Any spatial contour can be applied to the film by the deep-drawing. The deep-drawing process can, although not shown in the figures, be supported in a conventional manner by temperature. For the deep-drawing process, blow molding methods or other forming methods are also considered as an alternative to the embossing/die-cutting operation of the die 17 of FIG. 3, in which the film is heated and brought into its final shape by suction.

(25) After opening the die 17 from the state of FIG. 4, the deep-drawn film 21 can be removed, and be fed to another die 10. Such a second die 17b is shown in FIGS. 5 to 8.

(26) The invention also comprises when the film 21 remains in the lower die part 19 after the deep-drawing process, and only the upper die part is exchanged. In the following it is assumed that, starting from FIG. 5, the deep-drawn film 21 has been brought into another, second lower die part 23 of another die 17b.

(27) As shown in FIG. 5, the pourable or flowable mass of partly expanded particles 31a, 31b, 31c is brought into the lower die part 23 in a cavity 22 that serves for receiving the partly expanded particles 31a, 31b, 31c, and that faces the back side 35 of the deep-drawn film 21. A filling of the second lower die part 23 or the cavity 22 provided for this purpose can be done manually or by machine or with machine assistance until a predetermined volume or predetermined mass of partly expanded particles 31a, 31b, 31c is positioned in the cavity 22 and, in particular, also distributed.

(28) In this case, a holding or extraction device not shown in the figures can be provided that distributes the particles evenly along the cavity 22 in the manner of a feed head.

(29) The die 17b is then closed. For this purpose, an upper die part 24 is moved from a state according to FIG. 6, in which the die 17b is still partly opened, into a closed state. The cavity 22 is now closed on all sides.

(30) FIG. 7 indicates a heater 25 that tempers the die 17b, preferably both lower die part 23 and upper die part 24. The mold temperature is selected according to the materials used for the particle foam.

(31) As a result of the effect of temperature, the partly expanded particles 31a, 31b, 31c are completely expanded. A honeycomb structure can be seen, only indicated by way of example in FIG. 8. This is also to be understood only schematically: in fact, the structure of the completely expanded particle foam will be irregular. Another comparable structure is shown in FIG. 11:

(32) Here, instead of the frame structure of FIG. 8, an irregular polygonal structure is shown in the schematic sectional representation.

(33) FIG. 8 makes it clear that the partly expanded particles 31a, 31b, 31c according to FIG. 7 mutate to completely expanded particles 32a, 32b, 32c, wherein free spaces no longer remain between individual expanded particles 32a, 32b, 32c. FIG. 7 indicates such free spaces, exemplified by 36, on the other hand.

(34) It should be noted that the term fully expanded particles 32a, 32b, 32c is misleading:

(35) In fact, the multiplicity of completely expanded particles 32a, 32b, 32c together form a completely expanded particle foam mass 33 or a completely expanded particle foam. As can be seen from FIG. 8, this can cure within a short time, so that, as FIG. 8 indicates, the die is opened, and the upper die part 24 can be lifted off the lower die part 23. Now, the thus formed molded article 10 can be removed from the mold.

(36) As a result of the process of final-expanding, when the die is closed, the particle foam permanently and firmly bonds to the inner side 35 of the deep-drawn film 21. As a result, a lightweight, rigid and stable and yet inexpensive to produce composite construction element is provided.

(37) As shown in FIG. 9, if necessary, projecting regions 34a, 34b of the film 21 can have been separated along the separation lines 29a, 29b.

(38) The embodiment of FIG. 10 shows the back side 27 of the construction element 10 that can be provided with an additional layer 28, for example, plastic.

(39) The invention also comprises construction elements in which, instead of a deep-drawn film 21 of ABS or PMMA, a thin film of polyethylene or polypropylene, or in particular also so-called slush skins, are used as the substrate 21.

(40) The side 26 of the deep-drawn film 21 that faces away from the cured-particle foam mass 33, can form a high-quality surface. Since the provision of a deep-drawn film 21 can be made using conventional known and proven materials, the corresponding surface properties of the conventional materials can be used.

(41) The invention also comprises when the surface 26 of the substrate 21 is subjected to a separate processing in order to provide a high-quality surface. For example, processing steps such as polishing, painting, steaming, roughening, wetting, etc. can be considered.

(42) In FIG. 8, the wall thicknesses W.sub.1 of the deep-drawn film 21 or of the substrate and W.sub.2, namely the wall thickness of the cured-particle foam mass 33, are indicated by way of example. The wall thickness W.sub.1 can be between 0.2 mm and 13 mm, and the wall thickness W.sub.2 between 1 cm and 30 cm.

(43) The invention particularly comprises construction elements that are configured as caravan wall elements. For example, wall sections of a caravan trailer or a caravan, or complete wall elements of a caravan, can be used in vehicle construction, using the method according to the invention.

(44) The invention further comprises embodiments that provide that reinforcing elements are accommodated in the cavity 22 before filling the cavity 22 with partly expanded particles 31a, 31b, 31c.

(45) The reinforcing elements not shown in the Figures can have, for example, reinforcing fibers. As a result of filling the cavity 22 with partly expanded particles 31a, 31b, 31c, the particles are equally distributed and surround the reinforcement elements on several sides, preferably on all sides. The finished manufactured construction element 10 comprises a cured-particle foam mass that encloses the reinforcing elements securely. In particular, tensile forces can be transmitted and intercepted by positioning the reinforcing elements.