Construction panel having improved fixing strength

Abstract

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.

Claims

1. A plasterboard comprising a gypsum matrix having wood particles embedded therein in an amount of at least 2 wt % and less than 8 wt % relative to the gypsum, the gypsum matrix further comprising glass fibres in an amount of at least 1 wt % relative to the gypsum; and wherein no backing lamina is attached to either face of the plasterboard.

2. A plasterboard according to claim 1, wherein the maximum dimension of the particles is in the range 0.5-25 mm.

3. A plasterboard according to claim 1, wherein the plasterboard has a paper facing on one or both sides thereof.

4. A plasterboard according to claim 1, wherein the plasterboard has a mat partially or fully embedded at its surface.

5. A plasterboard according to claim 4, wherein the mat is a glass fibre mat.

6. A plasterboard according to claim 1, wherein the wood particles are irregular in shape.

7. A plasterboard according to claim 1, wherein the wood particles have a length that is greater than 0.5 mm.

8. A plasterboard according to claim 1, wherein the wood particles have a length that is less than 25 mm.

9. A plasterboard according to claim 1, wherein the wood particles have a thickness that is less than 4 mm.

10. A plasterboard according to claim 3, wherein the paper facing comprises both glass fibres and cellulose fibres.

11. A plasterboard according to claim 1, wherein the gypsum matrix comprises a hydrophobic additive.

12. A plasterboard according to claim 11, wherein the hydrophobic additive is silicone oil or wax.

13. A plasterboard according to claim 1, wherein the gypsum matrix comprises an anti-shrinkage agent.

14. A plasterboard according to claim 13, wherein the anti-shrinkage agent is unexpanded vermiculite, microsilica, and/or clay.

15. A plasterboard according to claim 1, wherein the plasterboard comprises foam.

16. A plasterboard according to claim 1, wherein the plasterboard comprises a lightweight aggregate.

17. A plasterboard according to claim 16, wherein the lightweight aggregate is perlite.

Description

DETAILED DESCRIPTION

(1) The invention will now be described by way of example only.

(2) Gypsum plasterboards were prepared using the following general methodology:

(3) 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.

(4) The dry powdered additives were added to the wet additives in the bowl and mixed in with the electric mixer for 30 s.

(5) 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.

(6) The panels had a thickness of 12.5 mm.

COMPARATIVE EXAMPLE 1

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

COMPARATIVE EXAMPLE 2

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

EXAMPLE 1

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

EXAMPLE 2

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

EXAMPLE 3

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

COMPARATIVE EXAMPLE 3

(12) A gypsum plasterboard was prepared from a slurry containing the following ingredients: stucco; woodchips in an amount of 3 wt % 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

(13) 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.

(14) The specimen was then mounted in a Zwick Universal Testing Machine and a 10N 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.

(15) The results are set out in Table 1. These are averages, each taken from 8 samples.

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