Construction Panel Having Improved Fixing Strength

Abstract

A plasterboard comprises a gypsum matrix having particles of agglomerated fibres embedded therein in an amount of at least 1 wt % relative to the gypsum, the gypsum matrix further comprising a polymeric additive, the polymeric additive being present in an amount of at least 1 wt % relative to the gypsum.

Claims

1. A plasterboard comprising a gypsum matrix having particles of agglomerated fibres embedded therein in an amount of at least 1 wt % relative to the gypsum, the gypsum matrix further comprising a polymeric additive, the polymeric additive being present in an amount of at least 1 wt % relative to the gypsum; wherein no backing lamina is attached to either face of the plasterboard.

2. A plasterboard according to claim 1, wherein the polymeric additive is present in an amount of at least 4 wt % relative to the gypsum.

3. A plasterboard according to claim 1, wherein the particles are present in an amount of at least 2 wt % relative to the gypsum.

4. A plasterboard according to claim 1, wherein the particles are wood particles.

5. A plasterboard according to claim 4, wherein a length of the wood particles is in the range 0.5-25 mm.

6. A plasterboard according to claim 4, wherein a thickness of the wood particles is less than 4 mm.

7. A plasterboard according to claim 4, wherein the plasterboard further comprises glass fibres.

8. A plasterboard according to claim 7, wherein the glass fibres are present in an amount of at least 1 wt %.

9. A plasterboard according to claim 1, wherein the polymeric additive is selected from group: polyvinyl acetate, poly vinyl acetate-ethylene co-polymer, polyvinyl pyrrolidone crosslinked with polystyrene sulfonate, polyvinyl alcohol, methyl cellulose, hydroxyethyl methyl cellulose, styrene-butadiene copolymer latex, acrylic ester latex, acrylic copolymer latex, polyester resin, epoxy resin, polymethyl methacrylate, polyacrylic acid, cationic starch, ethylated starch, dextrin, and a combination thereof.

10. A plasterboard according to claim 1, wherein the polymeric additive is starch or polyvinyl acetate.

11. A plasterboard according to claim 10, wherein the polymeric additive is polyvinyl acetate.

12. A plasterboard comprising a gypsum matrix having wood particles embedded therein in an amount of at least 2 wt % relative to the gypsum, the gypsum matrix further comprising glass fibres in an amount of at least 1 wt % relative to the gypsum.

13. A plasterboard according to claim 12, wherein the plasterboard includes opposing exterior faces and no backing lamina is attached to either of the opposed exterior faces.

14. A plasterboard according to claim 12, wherein a maximum dimension of the particles is in the range 0.5-25 mm.

Description

DETAILED DESCRIPTION

[0035] The invention will now be described by way of example only.

[0036] Gypsum plasterboards were prepared using the following general methodology: Stucco and other dry additives (including woodchips) were weighed into a bag and shaken to mix them. Water and wet additives were weighed into a bowl and mixed using an electric mixer for 60 s.

[0037] The dry powdered additives were added to the wet additives in the bowl and mixed in with the electric mixer for 30 s.

[0038] The resultant slurry was sandwiched between two sheets of paper liner and allowed to hydrate for 25 minutes measured from the time of mixing. The board was then dried in an oven for 1 hour at 160° C.

[0039] The panels had a thickness of 12.5 mm.

EXAMPLE 1

[0040] A gypsum plasterboard was prepared from a slurry containing the following ingredients: [0041] stucco; [0042] woodchips in an amount of 3wt % relative to the stucco. The woodchips had a maximum dimension in the range 1-20 mm and a thickness of 0.5-3 mm; [0043] corn starch (Merifilm from Tate & Lyle) in an amount of 6 wt % relative to the stucco.

EXAMPLE 2

[0044] A gypsum plasterboard was prepared from a slurry containing the following ingredients: [0045] stucco; [0046] woodchips in an amount of 3wt % relative to the stucco. The woodchips had a maximum dimension in the range 1-20 mm and a thickness of 0.5-3 mm; [0047] polyvinyl acetate (Vinamul 8481) in an amount of 6 wt % relative to the stucco.

EXAMPLE 3

[0048] A gypsum plasterboard was prepared from a slurry containing the following ingredients: [0049] stucco; [0050] woodchips in an amount of 3wt % relative to the stucco. The woodchips had a maximum dimension in the range 1-20 mm and a thickness of 0.5-3 mm; [0051] corn starch (Merifilm from Tate & Lyle) in an amount of 12 wt % relative to the stucco; [0052] glass fibres in an amount of 2 wt % relative to the stucco.

EXAMPLE 4

[0053] A gypsum plasterboard was prepared from a slurry containing the following ingredients: [0054] stucco; [0055] woodchips in an amount of 3wt % relative to the stucco. The woodchips had a maximum dimension in the range 1-20 mm and a thickness of 0.5-3 mm; [0056] polyvinyl acetate (Vinamul 8481) in an amount of 12 wt % relative to the stucco; [0057] glass fibres in an amount of 2 wt % relative to the stucco.

COMPARATIVE EXAMPLE 1

[0058] A gypsum plasterboard was prepared from a slurry containing the following ingredients: [0059] stucco; [0060] woodchips in an amount of 3wt % relative to the stucco. The woodchips had a maximum dimension in the range 1-20 mm and a thickness of 0.5-3 mm; [0061] glass fibres in an amount of 2 wt % relative to the stucco.

COMPARATIVE EXAMPLE 2

[0062] A gypsum plasterboard was prepared from a slurry containing the following ingredients: [0063] stucco; [0064] woodchips in an amount of 3wt % relative to the stucco. The woodchips had a maximum dimension in the range 1-20 mm and a thickness of 0.5-3 mm.

Screw Pull-Out Strength

[0065] Screw pull-out tests were carried out on samples measuring 100 mm by 100 mm that had been conditioned at a temperature of 23° C. and a relative humidity of 50%. A 50 mm single thread wood screw was inserted into the sample, passing through a metal load transfer element positioned on the surface of the sample. The load transfer element has a first portion that is configured to lie between the screw head and the surface of the sample, and a second portion that is configured to engage with a testing machine so as to allow a load to be applied to the screw along the axis of the screw. The screw was tightened to a torque of 1 Nm.

[0066] The specimen was then mounted in a Zwick Universal Testing Machine and a 10 N pre-load applied to the screw along the axis of the screw. Subsequently, the load was increased by setting a constant cross-head speed of 10 mm/minute until pull out was achieved.

[0067] The results are set out in Table 1. These are averages, each taken from 8 samples.

TABLE-US-00001 TABLE 1 Average screw Example pull-out strength Example 1 523 ± 88 Example 2 795 ± 93 Example 3 794 ± 82 Example 4 1097 ± 131 Comparative Example 1 336 ± 46 Comparative example 2 177 ± 95