Gypsum plasterboard

Abstract

The invention concerns a gypsum plasterboard (10) comprising at least an upper gypsum layer (16) having a first density, first hardness and first thickness and a lower gypsum layer (17) having a second density, a second hardness and a second thickness. The first density is lower than the second density and/or the first hardness is lower than the second hardness, and the first thickness is lower than the second thickness. The plasterboard according to the invention are heavy or dense plasterboards with an enhanced fixing ability.

Claims

1. A gypsum plasterboard comprising at least an upper gypsum layer having a first hardness and a first thickness and a lower gypsum layer having a second hardness and a second thickness, wherein the first thickness is lower than the second thickness and wherein the first hardness is lower than the second hardness.

2. The gypsum plasterboard of claim 1, wherein a ratio of the first thickness to the second thickness is lower than 1:1.05.

3. The gypsum plasterboard of claim 1, wherein the first thickness is higher than 0.5 mm and lower than 5.0 mm.

4. The gypsum plasterboard of claim 1, wherein the first hardness is >13 mm.

5. The gypsum plasterboard of claim 1, wherein a ratio of the first hardness to the second hardness is ≤1.3.

6. The gypsum plasterboard of claim 1, wherein the upper and lower gypsum layers are distinguished by a pore volume, wherein a pore volume of the upper gypsum layer is higher than a pore volume of the second lower gypsum layer.

7. The gypsum plasterboard of claim 1, wherein the plasterboard is clad in a facer.

8. A drywall construction comprising a gypsum plasterboard according to claim 1, wherein the plasterboard comprises an upper gypsum layer having a first density, a first hardness and a first thickness and a lower gypsum layer having a second density, second hardness and a second thickness, wherein the first density is lower than the second density and wherein the first hardness is lower than the second hardness, wherein the first thickness is lower than the second thickness, wherein the upper gypsum layer is arranged on a visible side of the plasterboard and wherein a head of a fastening means comprising a screw or a nail is located on the upper gypsum layer.

9. A drywall construction comprising at least one gypsum plasterboard according to claim 1 and at least one stud, wherein the at least one plasterboard is mounted or mountable to the at least one stud, the plasterboard comprising at least an upper gypsum layer having a first density, a first hardness and a first thickness and a lower gypsum layer having a second density, a second hardness and a second thickness, wherein the first density is lower than the second density and wherein the first hardness is lower than the second hardness, wherein the first thickness is lower than the second thickness, and wherein the upper gypsum layer is adjacent to a visible face or provides the visible face of the plasterboard when mounted to the stud.

10. A method of fastening a gypsum plasterboard according to claim 1, wherein the plasterboard comprises at least an upper gypsum layer having a first density, a first hardness and a first thickness and a lower gypsum layer having a second density, a second hardness and a second thickness, wherein the first density is lower than the second density and wherein the first hardness is lower than the second hardness, wherein the first thickness is lower than the second thickness, wherein the method comprises fastening the plasterboard via at least one fastening means comprising a head portion, the fastening means comprising a screw or a nail, wherein the fastening means is inserted into the gypsum plasterboard from a visible face being adjacent to the upper gypsum layer.

11. The gypsum plasterboard of claim 1, wherein the upper gypsum layer has a first density and the lower gypsum layer has a second density, and wherein the first density is lower than the second density.

12. The gypsum plasterboard of claim 11, wherein the first density is ≤880 kg/m.sup.3.

13. The gypsum plasterboard of claim 11, wherein a ratio of the first density to the second density is ≤0.9.

14. The gypsum plasterboard of claim 1, wherein a ratio of the first thickness to the second thickness is lower than 1:2.

15. The gypsum plasterboard of claim 1, wherein a ratio of the first thickness to the second thickness is higher than 1:50.

16. The gypsum plasterboard of claim 1, wherein a ratio of the first thickness to the second thickness is higher than 1:20.

17. The gypsum plasterboard of claim 11, wherein the second density is ≥880 kg/m.sup.3.

18. The gypsum plasterboard of claim 1, wherein the second hardness is ≤12 mm.

19. The gypsum plasterboard of claim 1, wherein a ratio of the first hardness to the second hardness is ≥1.1.

20. A gypsum plasterboard comprising at least an upper gypsum layer having a first density and a first thickness and a lower gypsum layer having a second density and a second thickness, wherein the first density is lower than the second density and wherein the first thickness is lower than the second thickness.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The enclosed figures illustrate the invention in more detail. The figures show:

(2) FIG. 1: A schematic cross-section of a gypsum plasterboard system according to the prior art;

(3) FIG. 2: a gypsum plasterboard system of FIG. 1 with inserted screw;

(4) FIG. 3: a schematic cross-section of a further example of a gypsum plasterboard according to the prior art;

(5) FIG. 4: a first structure obtained when inserting the screw in the plasterboard system of FIG. 3;

(6) FIG. 5: a second potential result when inserting the screw of the plasterboard system of FIG. 3;

(7) FIG. 6: a schematic cross-section of a gypsum plasterboard system according to the invention;

(8) FIG. 7: the gypsum plasterboard system of FIG. 6 with inserted screw;

(9) FIG. 8: schematic cross-sections of a gypsum plasterboard system according to the prior art in comparison with the present invention; and

(10) FIG. 9: a further comparison of the present invention with the prior art similar to FIG. 8.

DESCRIPTION OF THE INVENTION

(11) FIG. 1 shows a gypsum plasterboard system according to an example of the prior art. In this case, the gypsum plasterboard system comprises a gypsum plasterboard 10 having a raw density of e.g. less than 800 kg/m.sup.3 (standard gypsum board), a screw 11 and a fastening profile element 12 (e.g. made of metal, in particular a steel stud). FIG. 2 shows the system of FIG. 1 with inserted screw 11. A portion around a head 13 of the screw 11 is compressed so that a compressed portion 14 is formed

(12) FIG. 3 shows another example of a gypsum plasterboard system according to the prior art. Contrary to FIGS. 1 and 2 (showing a standard, comparatively soft gypsum board), the gypsum plasterboard 11 of FIG. 3 is comparatively hard or of a high density (e.g. of more than 1000 kg/m.sup.3). As can be seen in FIG. 4, when inserting the screw 11, there is a back buckling effect of the fastening profile element when the screw head and a board surface 15 of the gypsum plasterboard 10 contact each other.

(13) Moreover, the screw head does not enter the gypsum plasterboard 10 so that the screw 11 rotates without grip.

(14) FIG. 5 shows a case where the screw head 13 of the screw 11 enters the gypsum plasterboard 10, when providing a gypsum plasterboard according to FIG. 3. In this case, the grip in the fastening profile element remains sufficient (because the screw head is allowed to enter the board's surface), but since the gypsum of the gypsum plasterboard is (more or less) incompressible because of its high density, the gypsum bulges around the head 13.

(15) FIG. 6 shows a plasterboard system according to the invention. There, the gypsum plasterboard 10 comprises an upper gypsum layer 16 and a lower gypsum layer 17. Furthermore a screw 11 and a fastening profile element 12 are provided as shown in the prior art according to FIGS. 1 to 5. The upper gypsum layer 16 has a (raw) density of less than 800 kg/m.sup.3. The lower gypsum layer 17 has a (raw) density of more than 1000 kg/m.sup.3.

(16) As can be seen in FIG. 7, the gypsum close to the board surface 15 is compressed in a compressed portion 14 and the screw head 13 enters the gypsum plasterboard 10. In particular, the screw head 13 is flush-fitting to the board surface. Moreover, there is a good grip in the fastening profile element due to the (hard) lower gypsum layer 17 (and also due to the compressed portion 14).

(17) FIG. 8 shows a comparison between a plasterboard system with a comparatively soft gypsum plasterboard according to the prior art (left part of FIG. 8), a gypsum plasterboard system with a comparatively hard gypsum plasterboard according to the prior art (FIG. 8, middle portion) and a gypsum plasterboard system with a multilayer gypsum plasterboard according to the invention (FIG. 8, right part). In all gypsum plasterboard systems according to FIG. 8, a wall plug 19 holds a corresponding screw 11. As indicated by arrows 20, a load-bearing capacity (for pull-out) is for the gypsum plasterboard system in the left part of FIG. 8 substantially lower than for the middle and right part. In particular, since the grip of the wall plug is (also in the right part of FIG. 8, according to the invention) at least substantially located in the lower gypsum layer, there is no (substantial) difference between the example according to the middle part of FIG. 8 and the inventive embodiment according to the right part of FIG. 8.

(18) FIG. 9 shows a plasterboard system according to a first example of the prior art (left part of FIG. 9), according to a second example of the prior art (FIG. 9, middle portion) and according to the invention (FIG. 9, right part). As can be seen, a load-bearing capacity for pull-out of the screw 11 is in FIG. 9, left part, substantially lower than in the middle part of FIG. 9 (prior art) and the right part of FIG. 9 (invention). Moreover, in the right part of FIG. 9 (invention) the load-bearing capacity (for pull-out of the screw 11) is only minimally lower than in the prior art example according to the middle portion of FIG. 9. This results from the comparatively thin upper gypsum layer with respect to the comparatively thick lower gypsum layer. In a case where a thread portion of the screw 11 would be located only in the lower gypsum layer, there would be no (substantial) difference.

REFERENCE NUMERALS

(19) 10 Gypsum plasterboard

(20) 11 Screw

(21) 12 Fastening profile element

(22) 13 Screw Head

(23) 14 Compressed portion

(24) 15 Board surface

(25) 16 Upper gypsum layer

(26) 17 Lower gypsum layer

(27) 19 Wall plug

(28) 20 Arrow