AU608862B2 - Improvements in panels - Google Patents

Description

II ZAXMAn8?douW1N)iiq J3pD 9V id OL 1111.25 14 1111 IIHI1.4 COMMONWEALTH OF AUSTRALi~b 2 Patenis Act 1952-1969 C OMPLETE SPECIFIAIN (ORIGNAL) PATENT, TRADE M A'KS) (ORGINL)& DLUiCl' 3 ICE -1 JUL 1938 FOR OFFICE USE: SOUTH AUSTRALIA Class int lass Application Number Lodged Complete Application No.

Specification Lodged Published 0 0:Priority: o Oo l 1 Felated art: G0 00 0 0 E~i ,Name of Applicant; 0 00 0 0.

6 9 0Address of Applicant: TO BE COMPLETED BY APPLICANT FYREGUARD PTY. LTD.

10-12 Rosslyn Street, MILE END S.A. 5031 Actual Inventor; X\ddress for Service; COLLISON CO., Patent Attorneys, 117 King WViliam Street, Adelaide, South Australia, 5000, Complete Specification for the invention entitled: IMPROVribENTS IN PANELS The following statemont Is a full description of this Invention, Including the best method of performing It known toXmXUS: REPRINT OF RECEIPT AOOO IL4:3 01/07/88 r' II I I--1 I a 2 This invention relates to improvements in ceiling panels and more particularly to ceiling panels adapted to fit into suspended ceiling arrangements.

Ceiling panels incorporated into suspended ceiling arrangements are generally used in office buildings and are of particular advantage because individual panels, which may be ,of a size of 600 millimetres by 1200 millimetres or any other convenient size, can be lifted for access to wiring and ducting services in a ceiling space.

It is desirable however that such panels be relatively ligntweight and have good fire resistance as well as good acoustic and insulation properties. In a large multi-storey building for instance, even a S slight increase in weight of each panel will add considerably to the 15 total weight of the building. Conversely a lighter building panel, still having desirable properties as discussed above, will considerably reduce the overall weight of the building and hence the necessary strength of the various structural components.

Existing ceiling panels have weights of 15 to 20 kilograms per 20 square metre and it is the object of t'.is invention to provide a building panel with considerable less weight than these.

0 94 0 00 0 0• 00 0 6 0 00 O0 Now looking at the published literature on panels it can be seen that Australian patent specification No. AU-A-40229.'S5 describes a method of manufacture of a composite building panel which includes a central core of rigid polystyrene being encased on either side, with fibreglass reinforced gypsum plaster. A considerable thickness of gypsum plaster is recommended on either side of the panel. This does not provide a suitable structure for a ceiling tile as the overall composite is too heavy. This patent specification does not discuss any suitable edge finishing and hence as tiles are required to be discreet articles, such a method of manufacture is not suitabie for ceiling tiles. Further polystyrene has the problem that it is flammable or decomposable with heat so that noxious fumes are produced and hence this particular material is not satisfactory as a core material for ceiling tiles.

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3 Australian patent specification No. 531886 describes a building ,'lement including a central core of plastics material with the example being given again of expanded polystyrene coated with a waterproof coating such as an epoxy resin and a fibreglass mat bonded with a polyester resin. This would give a budiding panel which is extremely expensive owing to the cost of epoxy resin and polyester resin and is very heavy and once again is most unsuitable for ceiling 1 0 tiles, which as discussed above should be light and fire proof. Clearly the epoxy resin and polyester resin are not themselves fire proof.

Also this specification does not teach any edge treatment and hence is not suitable for tiles.

1 5 Australian patent specification No. 533452 describes a building component having a substrate of substantially rigir material with at least one facing of an inorganic fibrous sheet with o thermosetting 0 a 0 polymer and gypsum mixture. This provides a building panel which is expensive owing to the provision of the thermosetting polymer and once again no edge treatment is discussed. In general all of these building panels discussed above are applicable for wall panelling because of their thickness and weight.

It has been surprisingly found that a gypsum plaster will wet a nonwoven thin layer of fibrous material to provide a substantially reinforced surface foi a ceiling panel and hence the thickness of the coating on one or both sides of a panel can be considerably reduced.

This present invention therefore provides a ceiling tile comprising a lightweight central core having a thin surface coating on each face of S the core and at least a peripheral reinforcing band wherein the thin surface coating comprises a non-woven fibrous tissue and gypsum plaster the central core is a cardboard honey comb, and the peripheral S reinforcing band comprises glass rovings wound around the periphery in a gypsum plaster.

0 o 9 0 o. Preferably the 4i~i. central core may be filled with a phenolic foam, a rolyurethane foam or a polyisocyanurate foam. Such foams are fire resistant and will not 6-compose to noxious products easily. Further the coating of plaster on each face will reduce thermal attack on the core.

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4 Alternatively the central core may compose a honeycomb arrangement of cardboard having the interstices filled with vermiculite or pearlite, either unbound or bound with gypsum plaster or silicates or other binders.

The non-woven fibrous tissue may be a glass fibre tissue or chopped strand glass fibre mat or a polyester or other synthetic fibre tissue having the weight of 15 to 225 grams per square metre.

There may be furthe" included, reinforcing bands extending across the tile comprised of r .,sum plaster reinforced with glass fibre rovings.

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4 I 4 ,r There may be further included a plurality of randomly positioned holes on the front face of the tile whereby to provide improved acoustic properties.

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In a further preferred form, the invention may be said to reside in a ceiling tile including a core comprising phenolic foam reinforced with honeycomb of cardboard with a thickness of the core of from 15 to millimetre, a surface coating on the front and rear surfaces comprising gypsum plaster reinforced with glass fibre tissue, having a weight of from 15 to 225 grams per square metre and at least a peripheral band of gypsum plaster having glass fibre roving reinforcement. Preferably the glass fibre tissue has a weight of grams per square metre.

rt r c ri r r i r r l 1 t It *1~b In essence therefore the ceiling panel of the present inventiorn comprises a gypsum plaster surface reinforced with fibrous material, with the thickness of the surface being from 1 to 3 millimetres and then a core of honeycomb cardboard which may be reinforced with phenolic or similar foam core, with a rear surface having a further coating of gypsum plaster reinforced with fibrous tissue, also to a thickness of 1 to 3 millimetres. Around the periphery of the panel 1 0 maybe thicker gypsum plaster with glass roving reinforcement. This panel has excellent fire resistance being non burning and non-smoking and having good acoustic absorption properties. A- indicated above the acoustic properties of the tile may be further improved by providing a plurality of small holes punched onto the face surface of 1 5 the tile in a random manner and this has been found to provide 0o0 particular good acoustic absorption properties. Such holes may extend through the surface layer and into the core. These holes also provide advantageous visual effect. The foam core provides good 0 thermal insulation properties as well, 0 0 0 In one preferred form, a panel size of 1200 millimetres by 600 o, oo millimetres may be used to coincide with existing ceiling tile o, hanging systems and to enable the use of existing forms of lighting arrangements. Such a panel may have two core panels for instance of phenolic foam core with honeycomb cardboard reinforcing each approximately 570 millimetres by 570 millimetres by millimetres. Around the periphery of the tile and across the middle of the tile between the two core panels is provided continuous glass fibre rovings to provide reinforcement and including gypsum plaster reinforced glass fibre tissue on each surface and gypsum plaster 0 O 1* filling the peripheries of the cores.

A tile made according to this type of specification may have a weight of 5.8 kilograms per square metre which compares favourably with «.o3 existing tiles which provide similar properties but which have S masses of 15 to 20 kilograms per square metre, On a large building job when many thousands of square metres of ceiling yd" 6 tiles may be used, considerable weight reductions in multi-storey buildings can be achieved.

This then generally describes the present invention but to assist with understanding of the invention, reference will now be made to the accompanying drawings which show a typical tile according to this invention and the various ways in which the ceiling tiles of the present invention may be constructed.

In the drawings:- 00 FIG. 1 shows a cross-section of the edge of a ceiling tile according to an embodiment of the present invention with the various 0,o components illustrated.

"015 ao 096 0 FIG. 2 shows a honeycomb arrangement of the core.

p pp p SFIG. 3 shows a longitudinal section through a ceiling tile.

'b620 FIG. 4 shows a face view of a ceiling tile according to this invention and FIG. 5 shows a rear perspective view of a ceiling tile according to this invention.

r Now looking more closely at the drawings it will be seen that in FIG.

1 that the ceiling tile shown as 1 comprises generally a front surface coating 2 of gypsum plaster with a fibrous reinforcing sheet 3 and similarly the rear surface 4 comprises gypsum plaster with a reinforcing sheet 5. In between the front and rear surfaces there is a core comprising phenolic foam 6, with a honeycomb cardboard reinforcing 7. Randomly positioned into the front face 2 and extending into the core are holes 8 to provide desirable acoustic properties for the tile.

Around the edge of the tile a reinforcing band 9 comprised of gypsum plaster and fibreglass rovings 10. A decorative ridge 11 is 7 provided on the upper surface and a stepped-:n portion/i provided to fit onto a existing ceiling hanger arrangement.

FIG. 2 shows one preferred core construction of a honeycomb of phenolic foam 20 with cardboard 21. Such a core may be made continuously and then cut to the required thickness and sizes.

FIG. 3 shows a longitudinal cross-section through a ceiling tile and this embodiment two cores 25 and 26 are used with a peripheral reinforcing band 27 around the periphery of the tile and a central reinforcing band 28 across the middle of the tile, As in the previous embodiment, glass fibre tissue mats 29 are provided on the rear surface of the tile 30 and on the front surface of the tile, wet with a thin layer of gypsum plaster.

o o FIG. 4 shows a front face of a ceiling tile which includes the 0 00 peripheral band 27 of gypsum plaster reinforced with glass fibre I rovings and the central cross reinforcing band 28 again of gypsum plaster and glass fibre rovings. On the front face is a decorative raised ridge portion 31 and in the main face surface of each panel 0 are a number of apertures 32 providing good acoustic properties.

o o It will be seen from FIG. 5 that the rear surface 33 of the tile is substantially planar and is comprised of glass fibre tissue wet with gypsum plaster.

6 0 004 By having the coating on both the front and rear surfaces of the ceiling tile, and with a continuous gypsum plaster edge not providing direct access to the core, considerable fire resistance can be obtained and with the core being comprised of a phenolic or other foam or other material which i4 substantially fire resistant, a tile with considerably advantageous properties can be produced.

In general the manufacturing process for a ceiling tile of the present invention will comprise the following steps.

Gypsum plaster is prepared and placed into an individual mould for the tile and vibrated to remove any air in the plaster. Next glass 1" ir -Ylii-~i 8 tissue of the correct size is laid into the mould and smoothed off and then further plaster is spread into the mould and combed to provide a strongly adhering surface. Next foam blocks are added into the mould and glass fibre rovings are added around the edges of the mould and across any reinforcing bands. These gaps around the edges and across the middle are then filled with more gypsum plaster and further plaster is then spread over the foam blocks. A further surface tissue is then applied and then screeded to work plaster through the glass tissue. The tile is then allowed to set and is demoulded when cured which may be after approximately minutes.

This invention provides a ceiling tile which has considerably improved properties over prior art tiles.

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Claims (11)

1. A ceiling tile comprising a lightweight central core having a thin surface coating on each face of the core and at least a peripheral reinforcing band wherein the thin surface coating comprises a non- woven fibrous tissue and gypsum plaster the central core is a cardboard honey comb, and the peripheral reinforcing band comprises 1 0 glass rovings wound around the periphery in a gypsum plaster.

2. A ceiling tile as in claim 1, wherein the thickness of the surface coating is from one to three millimetres.

3. A ceiling tile as in claim 1, wherein the i4g-i central core of o4 cardboard honeycomb has its interstices filled with phenolic foam. a polyurethane foam, or a polyisocyanurate foam. S

4. A ceiling tile as in claim 1 wherein the central core has its 0 ,0 interstices filled with vermiculate or pearlite, either unbound or bound with gypsum plaster.

5. A ceiling tile as in claim 1 wherein the non-woven fibrous tissue is a glass fibre tissue, chopped strand glass fibre mat or a polyester tissue.

6. A ceiling tile as in any one preceding claim, further including oo," reinforcing bands extending across the tile comprised of gypsum o plaster reinforced with glass rovings.

7. A ceiling tile as in any one preceding claim further including a Splurality of randomly positioned holes on the front face of the tile, whereby to provide acoustic properties.

8, A ceiling tile including a r4g44 core, comprising a honeycomb of cardboard filled with phenolic foam with a thickness of the core of from 15 to 25 millimetres, a surface coating on the front and rear surfaces comprising gypsum plaster reinforced with glass fibre j tissue having from 15 to 225 grams per square metre weight and at least a peripheral band of gypsum plaster having glass fibre roving reinforcement.

9. A ceiling tile as in claim 7 wherein the glass fibre tissue has a wight of 40 grams per square metre.

L d/z *I i i i rl l A ceiling tile substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

11. A method of manufacturing a ceiling tile substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings. Dated this 21st day of December 1990 FYREGUARD PTY. LTD. S By their Patent Attorneys COLLISON CO. 4 4 4 04 0 t 4 o 4 0 4 4 4 °I a 1&