METHOD FOR PRODUCING DECORATIVE PARTS

Abstract

The invention relates to a method for producing decorative parts with a rear plastic carrier element, which is poured over with plastic under process pressure in a casting tool for producing an upper layer on a front visible side, characterized in that the carrier element is fixed in the casting tool and is impinged upon with pressure at least during the production of the upper layer at the rear and in the direction of the upper layer that is to be produced on the front visible side, said pressure counteracting the process pressure during the overmolding with plastic.

Claims

1. A method for producing decorative parts with a rear plastic carrier element which is overmolded in a casting tool for producing an upper layer on a front-side visible side with plastic under process pressure, characterized in that the carrier element is fixed in the casting tool 0 and is loaded by a pressure at least during the production of the upper layer on the rear and in the direction of the upper layer to be produced on the front, visible side, which pressure counteracts the process pressure during the overmolding with plastic.

2. The method according to claim 1, wherein the carrier element is loaded with pressure in a planar manner in the direction of the upper layer to be produced on the front side.

3. The method according to claim 1, wherein the pressure is produced by compressed gas, which is pressed into a cavity between an upper tool and the carrier element.

4. The method according to claim 3, wherein a seal is arranged between the upper tool and the carrier element which seals the cavity at least during the production of the upper layer.

5. The method according claim 1, wherein a maximum pressure is greater than or equal to a maximum process pressure.

6. The method according to claim 1, wherein the pressure is maintained at least as long as the process pressure of the overmolding is acting.

7. The method according to claim 1, wherein a control is provided which controls the level of the applied pressure.

8. The method according to claim 1, wherein the pressure is applied in several pressure stages with different pressure values.

9. The method according to claim 1, wherein the applied pressure is reduced step-by-step after the conclusion of the overmolding.

10. The method according to claim 1, wherein the carrier element is an injection-molded plastic carrier.

11. The method according to claim 1, wherein polyurethane is cast as plastic.

12. A casting tool for carrying out the production method according to claim 1, with an upper tool and a lower tool which comprise between themselves a hollow receiving space for the carrier element in the closed state which can be overmolded with plastic on the visible side facing the lower tool, wherein the upper tool comprises a passage extending outward from the hollow receiving space to which passage a producer of compressed gas can be connected so that the hollow receiving space can be loaded at least in sections with compressed gas, in with particular compressed air.

13. The casting tool according to claim 12, wherein a groove is provided in the upper tool on an inner side directed toward the lower tool into which groove a seal can be introduced for sealing the cavity between the carrier element and the upper tool.

14. The casting tool according to claim 12, wherein it comprises the producer of compressed gas.

15. The casting tool according to claim 12, wherein it comprises a control which controls the level of the pressure applied by the producer of compressed gas.

Description

[0020] Other advantageous further developments of the invention are characterized in the subclaims and are shown in detail in the following together with the description of the preferred embodiment of the invention using the FIGURE. In the FIGURE:

[0021] FIG. 1 shows a schematic side view of a casting tool for carrying out the method.

[0022] FIG. 1 shows by way of example in a schematic fashion a side view of a bipartite casting tool 1 with an upper tool 3 and a lower tool 2. In the closed state shown, a hollow receiving space is formed between the upper tool 3 and the lower tool into which space the carrier element 5 is inserted and fixed in such a manner that the hollow receiving space forms an open space between carrier element 5 and lower tool 2 and forms a cavity 9 between carrier element 5 and upper tool 3. The carrier element 5 is overmolded in the casting tool 1 on its visible side facing the lower tool 2 in order to produce the upper layer with polyurethane under process pressure, wherein the process pressure acts in the direction of the upper tool 3. The upper tool comprises a passage 8 extending out from the hollow receiving space and the cavity 9 to which passage a compressor which is not shown is connected in order to load the carrier element 5 with a pressure by compressed air at least during the production of the upper layer on the rear side and in the direction of the lower tool 2, i.e., the top layer to be generated on the front, visible side, which pressure counteracts the process pressure during the overmolding with plastic. In order to seal the cavity 9, a seal 4 is inserted between the carrier element 5 and the upper tool 3 which seal extends partially into a groove 7 formed on the upper tool 3 and directed toward the lower tool 2.

[0023] In the method for producing the decorative part, for example the injection-molded carrier element is fixed with a material layer (film, veneer, fiber mat or leather, etc.) in the casting tool 1 in such a manner that the cavity 9 is sealed, and subsequently polyurethane is pressed by the customary process pressure into the free space 6. At the same time a planar counterpressure acting on the carrier element 5 is produced via the passage 8 by compressed air and maintained until the process pressure can be reduced. Subsequently, even the pressure of the compressed air can be adapted in several pressure steps. The time of the application of pressure is variable and can be adapted by a control which is not shown to the process of the introduction of plastic or polyurethane.

[0024] The invention is not limited in its implementation to the previously indicated preferred exemplary embodiments but rather a number of variants is conceivable which make use of the presented solution even in basically differently designed embodiments. For example, the shapes and thicknesses of the carrier element and of the plastic layer to be applied can be varied. Also, different injection-molding polymers, carrier constructions (homogeneous or multilayer), carrier wall thicknesses, PUR systems (compact, foamed-on, hard, soft), a variable arrangement of the seal, for example on the casting tool or on the carrier element, different sealing materials as well as variable surface structures are comprised.