METHOD FOR FOAMING CHIPBOARDS WITH TUBES AND A CHIPBOARD WITH TUBES

Abstract

The invention relates to a method for foaming chipboard with tubes including a board body interspersed by tubes and having an upper and a lower face includes the steps of providing a corresponding chipboard with tubes, defining one or more machining regions on the upper and/or lower face of the chipboard with tubes, machining the machining regions.

In order to provide a method for foaming chipboard with tubes and a chipboard with tubes having foamed tubes that can be used in a simple, flexible, and cost-effective manner while also being highly robust, a foam-forming material is introduced at least in portions of at least one of the above-mentioned tubes in the machining region in order to locally reduce the difference in density between the tubes and the board body. The invention further relates to the use of a device for foaming tubes of a chipboard with tubes.

Claims

1. A method for foaming chipboards with tubes (10) comprising a board body (14) interspersed by tubes (12) and having surfaces comprising an upper face and a lower face (16, 18), said method comprising the steps of providing a chipboard with tubes (10), defining one or more machining regions (20) on the upper face and/or the lower face (16, 18) of the chipboard with tubes (10), introducing a foam-forming material into at least one of the above-mentioned tubes (12) in the machining region (20) in order to locally reduce the difference in density between the tubes (12) and the board body (14), machining the machining regions (20).

2. The method according to claim 1, wherein the foam-forming material is introduced into corresponding tubes (12) at least in the edge region (22) of the machining region (20).

3. The method according to claim 1, wherein a topology is created in at least one machining region (20) during the machining.

4. The method according to claim 3, wherein the topology is a decorative pattern.

5. The method according to claim 1, wherein a cutout (26) which penetrates the upper and lower face (16, 18) of the board body (14) is made in at least one machining region (20).

6. The method according to claim 5, wherein a frame is arranged in the edge region (22) of the cutouts (26).

7. The method according to claim 6, wherein the cutout (26) is filled with an infill after the arrangement of a frame.

8. The method according to claim 1, wherein the foam-forming material is introduced into a plurality of tubes (12) in each case in portions thereof.

9. The method according to claim 8, wherein, on account of the creation of a cutout (26), the plurality of tubes (12) are cut in the region of the portions that are filled with foam-forming material.

10. A chipboard with tubes, comprising a board body (14) traversed by tubes (12) and having surfaces, comprising an upper face and a lower face (16, 18), wherein one or more tubes (12) are foamed in portions with a foam-forming material in at least one machining region (20), and wherein the machining regions (20) each have a cutout (26) and/or a topology, on at least one surface.

11. The chipboard with tubes according to claim 10, wherein a frame is arranged in the machining regions (20) which comprise a cutout, in each case in the edge region (22) thereof, and an infill is arranged in the cutouts (26) framed by the frame, wherein the frame is in contact, at least in portions, with foamed portions of the tubes (12).

12. The chipboard with tubes according to claim 10, wherein the cutouts (26) penetrate the chipboard with tubes (10) completely.

13. The chipboard with tubes according to claim 10, wherein at least one infill is designed as a closure element.

14. The chipboard with tubes according to claim 10, wherein the flexural strength of the tube (12) filled with the foam-forming material is greater than the flexural strength of the non-foamed tube at least by a factor of 2 parallel to the direction of the tube.

15. The chipboard with tubes according to claim 10, wherein the tensile strength of the tube (12) filled with the foam-forming material is greater than the tensile strength of the non-foamed tube at least by a factor of 4.

16. Use of a device comprising at least one lance, a mixing and dosing system having a mixing head and at least two containers, as well as pumps, and lines between the lance, mixing and dosing system, pumps, and containers producing a foam-forming material and introducing the foam-forming material into a tube (12) of a chipboard with tubes (10).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Details of the invention are explained below using an exemplary embodiment with reference to the figures, in which:

[0032] FIG. 1 is a perspective view of a chipboard with tubes having a defined machining region according to one embodiment;

[0033] FIG. 2a is a perspective view of the chipboard with tubes from FIG. 1 with a cutout in the machining region;

[0034] FIG. 2b is a perspective view of a chipboard with tubes according to the invention with a cutout and tubes that are foamed in portions;

[0035] FIG. 3a is a normal view along a longitudinal axis of part of a chipboard with tubes prior to machining;

[0036] FIG. 3b shows the chipboard with tubes from FIG. 3a after machining.

DETAILED DESCRIPTION

[0037] FIG. 1 shows an example of a chipboard with tubes 10 having a board body 14 traversed by tubes 12. The board body 14 consists of chips mixed with binders and that were pressed in an extrusion process under pressure and heat and cut to the specified length. The width of the chipboard with tubes 10 is predetermined by the manufacturing method. The chipboard with tubes 10 in this case has a length L, a thickness D, and a width B, by way of example. The tubes 12 extend along the length L and thus in parallel with a longitudinal axis A of the board body 14. The board body 14 comprises an upper face 16 and a lower face 18, wherein a machining region 20 was defined on the upper face 16.

[0038] FIG. 2a illustrates the embodiment of the chipboard with tubes 10 according to FIG. 1 after machining, in this case the creation of a cutout 26. The cutout 26 extends in a cut direction S, which in this case is oriented perpendicularly to the upper face 16, and penetrates the chipboard with tubes lo completely, i.e. both the upper face 16 and the lower face 18. The cutout 26 cuts through a plurality of tubes 12 both in the direction of the longitudinal axis A and transversely thereto. The cutout 26 accordingly comprises an edge region 22, in which the board body 14 and the tubes 12 are cut either in the direction of the longitudinal axis or transversely thereto. FIG. 2a in particular illustrates how a concave recess 24 is left behind in the portions of the edge region 22 in which the tubes are cut in parallel with the longitudinal axis A. In contrast, the tubes 12 which are cut transversely to the longitudinal axis A by the cutout 26 have substantially the same characteristics as the tubes 12 on the free longitudinal ends of the chipboard with tubes 10.

[0039] FIG. 2b shows a chipboard with tubes 10 of the like illustrated by way of example in FIG. 2a, wherein the disadvantages of the aforementioned recess 24 have been improved according to the invention, in particular by means of foams 28 at least in portions. As shown in FIG. 2b, the former recess 24 now has a substantially planar cut surface parallel to the longitudinal axis A on account of the foam 28. Equally, the tubes 12 that are cut by the cutout 26 transversely to the longitudinal axis are no longer open in the corresponding edge region 22, but rather have also been provided with foam 28. Here, the foam 28 was in each case arranged prior to the machining for the cutout 26 and, more specifically, already when the corresponding machining region was defined. As described above, a mental definition is sufficient; a visible or tactile marking according to FIG. 1 is not absolutely necessary.

[0040] FIG. 3a shows an example of a portion of a chipboard with tubes 10 having three tubes 12 arranged at a distance X from one another and each having a tube diameter Y. It is clear that only the tubes 12 which are arranged in the region of a cut line 30, or which are cut thereby, comprise foam 28. If a tube 12 is at a sufficient distance from the future edge region 22 (FIG. 3b), said tube does not have to be provided with foam 28.

[0041] In a simple embodiment, the method according to the invention is carried out in such a way that a foam-forming material, e.g. a mixture of an isocyanate and a polyol in a ratio of 1:1.5 is introduced into a tube 12 of the chipboard with tubes 10, preferably at temperatures of between 10° C. and 40° C., for example by means of a lance that projects into the tube 12 to be foamed up to or into the machining region 20. At the inlet end, the lance is connected via a fluid line to a mixing and dosing system, in which the above-mentioned two-component mixture of isocyanate and polyol is metered, preferably by means of flow meters, and is mixed in a mixing head for immediate use. The mixing and dosing system is typically equipped with a container having a stirrer for each of the components of the foam-forming material, with pumps, flow meters, a mixing head, and with lines that connect the individual components of the mixing and dosing system to one another. The material or the components thereof are conveyed out of the containers in accordance with the respective flow meters by means of one or more pumps and through the mixing head to the outlet end of the lance. In this simple embodiment, the lance can be guided by hand. The length of the lance is approx. 2 m to 3 m. A typical mixing and dosing system dispenses approx. 20 g/second to 100 g/second of foam-forming material. In order to continuously produce this dispensing amount in the case of a two-component material, two containers each with a volume of approx. 200 l are required in order to stock one constituent of the material each. The stirrer ensures uniform dispensing of the relevant component at a consistent quality. The foam-forming material is introduced into the tube 12 to be foamed immediately after the two components have been mixed in the mixing head and foams in said tube after the lance has exited, as a result of which the tube 12 is filled with foam at least in portions. The foam-forming material exits the outlet end of the lance at a high pressure. High pressure should be understood in this case to mean outlet pressures of between 3 bar and 15 bar. The dwell time of the foam-forming material in the lance prior to being introduced into a tube 12 is therefore short in the high-pressure method presented above. This in particular has the advantage that the device can be used for longer in the case of a multi-component foam-forming material on account of the reduced need for cleaning and maintenance. Since only the mixture of the corresponding components, i.e. the material, is chemically rapidly reactive, in most cases only the lance has to be cleaned after production has been interrupted. In an alternative embodiment, in particular in procedures in which a slow-reacting material is used, it is also conceivable for the material to be introduced into a tube 12 of a chipboard with tubes 10 at a lower pressure, at a low pressure, from the lance.

[0042] In the case of longer tubes 12, e.g. for doors or wall elements, the foaming is preferably done in two steps. In a first step, the lance is introduced from a first end of the tube 12 and the tube 12 is foamed at least in portions from the center up to the first end of the tube 12. In a second step, the lance is then introduced from the opposing second end of the tube 12 and the tube 12 is foamed at least in portions between the center of the chipboard with tubes 10 and the second end. The foam-forming material is usually liquid until it leaves the lance, in particular if a high-pressure method is used, and foams up after leaving the lance. Preferably, a foam having a pore size of from 150 μm to 300 μm is produced. It usually takes approx. 15 minutes for the tube 12 to fill with foam.

[0043] According to an advantageous embodiment of the method, multiple chipboard with tubes 10 are processed at the same time. In this case, two or more lances are used at the same time. Preferably, a control unit is used, which controls individual lances or groups of lances in order to be able to foam each individual tube 12 at least in portions in accordance with the control unit even in the case of simultaneous foaming of multiple chipboard with tubes 10 or multiple tubes 12 in one or more chipboard with tubes 10. The control unit may preferably control and/or regulate the penetration depth of the lance into the tube and, if applicable, also the amount of foaming material introduced into the tube 12. A control unit is also understood to mean a robot that handles the lance.

[0044] According to another advantageous embodiment of the method, a conveyor belt or turntable may be used in order to foam one or more tubes 12 of a chipboard with tubes 10 at least in portions. In particular, if robots are used to guide the lance, it has proven advantageous to use a conveyor belt or turntable in order to be able to quickly process the chipboard with tubes 10, in which at least one tube 12 is to be foamed at least in portions. In particular, a conveyor belt or turntable on which a stack of chipboard with tubes 10 is layered one on top of the other has proven to be useful. One or more tubes 12 of the layered chipboard with tubes 10 may be foamed at least in portions one after the other or at the same time by a lance or a group of lances.

[0045] According to another preferred embodiment of the method, the conveyor belt or turntable are designed such that they can be tilted or inclined, preferably at an angle of up to 10°, referably up to 5°, proceeding from a horizontal position. If a chipboard with tubes 10 is inclined when foaming material is being introduced, the distribution of the material in the relevant tube 12 to be foamed can be optimized. For example, the lance can be designed to be shorter, because the distribution or flow of the material can be utilized in order to foam portions of the tube 12 that are far inside the chipboard with tubes 10. As such, the shorter lance can be introduced into the tube 12 and taken out again faster, which results in faster processing.

[0046] Optionally, the conveyor belt or turntable may be equipped with a film-wrapping device for the chipboard with tubes 10 having at least partially foamed tubes 12. As a result, the chipboard with tubes 10 are protected for transportation if the chipboard with tubes 10 are transported after foaming but prior to machining. In the case that the tube(s) 12 are foamed up to the edge of the chipboard with tubes 10, the foam is prevented from escaping from a tube 12 if said chipboard is wrapped in film. Furthermore, this effectively prevents the end faces from becoming soiled and the boards 10 sticking to one another due to any escaping foam.

[0047] According to another advantageous embodiment, a mixing or dosing system having the associated lance or lances and a control unit may also be arranged with two conveyor belts or turntables, since the time for orienting the new stack and, if applicable, for wrapping the processed stack in film can then be used to process a stack of chipboard with tubes 10 arranged on a second conveyor belt or turntable.

[0048] In addition, strength properties of a non-foamed tube 12 (before) and a foamed tube 12 (after) were determined. The following values were determined according to EN 14755: the flexural strength in the region of the tube 12 parallel to the tube 12 was 1.48 N/mm.sup.2 prior to foaming and 4.07 N/mm.sup.2 after foaming. The tensile strength in the region of the tube 12 was 0.46 N/mm.sup.2 prior to foaming and after foaming the tensile strength in the region of the tube 12 was 2.27 N/mm.sup.2. On account of the foaming of the tube 12, the density of the chipboard with tubes 10 increases from an average of 259 kg/m.sup.3 to 334 kg/m.sup.3.

[0049] The above-described aforementioned device and method features can each be freely and individually combined in order to optimize work.

LIST OF REFERENCE SIGNS

[0050] 10 Chipboard with tubes

[0051] 12 Tube

[0052] 14 Board body

[0053] 16 Upper face

[0054] 18 Lower face

[0055] 20 Machining region

[0056] 22 Edge region

[0057] 24 Recess

[0058] 26 Cutout

[0059] 28 Foam

[0060] 30 Cut line

[0061] A Longitudinal axis

[0062] B Width

[0063] D Thickness

[0064] L Length

[0065] S Cut direction

[0066] X Distance between tubes

[0067] Y Tube diameter