AU685480B2 - Applying a sheet material onto a surface of a fibrous material - Google Patents

Description

APPLYING A SHEET MATERIAL ONTO A SURFACE OF A FIBROUS MATERIAL

TECHNICAL HELD

This invention relates to methods and apparatus for applying sheet material onto a surface or surfaces of a mineral or fibre based material such as a building panel or

ceiling tile.

BACKGROUND ART

Removable building panels and/or ceiling tiles have been used extensively in many buildings, particularly in office and industrial environments. The panels are usually

constructed from mineral or fibre based materials or composite materials, for example,

wood, glass, mineral or glass fibre, cardboard, wood fibre or plaster. After a period of

time, tiles will often become damaged or discoloured particularly in the case of ceiling tiles which are subject to water damage. Often the tiles are expensive to remove and replace and replacement may also require the replacement of the ceiling grid from which the ceiling tiles are suspended in a building. Therefore refurbishment is desirable. Methods of refurbishment or manufacture of such building panels or ceiling tiles are known and one such method is disclosed in U.S. Patent No. 4,894,102. The method and apparatus for refurbishment or manufacture disclosed in the specification of U.S. Patent No. 4,894,102 relates to laminating a sheet material to the decorative surface of the tile or panel. U.S. 4,894,102 only provides for the lamination of impervious sheet materials to the outer surfaces of the tiles or panels to be refurbished. The use of an impervious sheet material to laminate to the tile or wall panel also has the disadvantage that the sheet material is often wasted as it has to cover the whole vacuum bed which is being used. This is particularly wasteful in the case of tiles or panels which are small relative to the size of the vacuum bed. Also, the curing oven used in U.S. Patent No. 4,894,102 relies upon heat being transferred to cure the adhered laminated materials by convection. This can cause heat damage to the sheet material being applied to the panel or tile and the construction is not suitable for drying tiles which have been subject

to water damage.

Furthermore, the use of a non-perforated (that is impervious) sheet material

seriously affects the acoustic valve of acoustic ceiling panels by up to 40%.

The apparatus and method disclosed in U.S. 4,894,102 only provides for the lamination of a sheet material to the decorative surface of the tile or panel. The edges of ceiling tiles and building panels are prone to damage and it is desirable to provide

additional strength and protection to the edges of such tiles or panels as the result of any refurbishment or manufacturing process. DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide methods or apparatus for

laminating a sheet material onto a surface of a mineral or fibre based material which will at least go some way toward overcoming the disadvantages of the prior art or which will at least provide the public with a useful choice.

Accordingly, in one aspect the invention consists in a method of laminating a sheet material onto a surface of a mineral or fibre based material. The method comprises the steps of; providing a resin or an adhesive on the sheet material or on the surface of the mineral or fibre based material, placing the sheet material on the surface so that the resin or adhesive is provided between the sheet material and the surface, placing a substantially impervious flexible cover over the sheet material, and applying a partial vacuum between the cover and a vacuum source to force the sheet material into contact with the mineral or fibre based material to laminate the sheet material to the surface. In a further aspect the invention consists in apparatus for laminating sheet material onto a surface of a mineral or fibre based material. The apparatus comprises a vacuum bed having a plurality of perforations through a material support surface of the bed. Air

is capable of being drawn through the perforations to form a partial vacuum. The apparatus also includes a substantially impervious flexible high temperature cover of size

sufficient to cover all the perforations in the vacuum bed. Vacuum apparatus is provided for establishing a partial vacuum via the perforations between the cover and the vacuum apparatus sufficient to at least force the cover into contact with the support surface.

The present invention provides advantages which are not disclosed in

U.S. 4,894,102. The provision of an impervious flexible cover provides the advantage that pervious sheet materials can be laminated to the mineral or fibre based material.

Thus the range of available sheet materials is increased and the acoustic performance of the ceiling tile is maintained or improved.

The use of an impervious cover also provides the advantage that very little sheet material is wasted as the cover can completely cover the vacuum bed.

Another aspect of the invention consists in a frame having venting means so that a partial vacuum can be established between the sheet material and the vacuum apparatus via the venting means. The frame allows the sheet material to be forced into contact with a first surface of the material and with a second opposite surface. The invention also consists in a method of laminating sheet material to a second opposite surface of a mineral or fibre based material.

This allows the sheet material to also cover parts of the other side of the mineral or fibre based material. In this way the upper or decorative surface of a tile or building panel, for example, and the undersurface adjacent to the edges can be laminated to the sheet material. This reinforces the edges and extends the life of the panel and adds to the appearance of the article.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention consists in the foregoing and also envisages constructions of which

the following gives examples.

One preferred form of the present invention will now be described with reference to the accompanying drawings in which;

Figure 1 is an exploded diagrammatic perspective view of apparatus for laminating

a sheet material onto the surface of a mineral or fibre based material or composite

material in accordance with the present invention;

Figure 2 is a perspective view of apparatus for applying adhesive or resin to a sheet material in accordance with the present invention;

Figure 3 is a diagrammatic cross-section through line AA of the apparatus shown

in Figure 1; Figure 4 is an enlarged view in cross section of part of the apparatus shown in

Figure 3;

Figure 5 is an enlarged view in cross section of part of a mineral or fibre based material or composite material having a sheet material laminated to the surface thereof;

Figures 6 to 8 are views in cross-section of part of a mineral or fibre based material or composite material having a sheet material covering the surface thereof and a flexible cover over the sheet material for laminating the sheet material to the mineral

or fibre based material or composite material;

Figure 9 is a further view of an alternative embodiment of the apparatus shown

in figure 3, including a wrapping frame or jig; Figure 10 is a plan view of the wrapping frame and jig included in figure 9; and

Figure 11 is an enlarged diagrammatic partial cross section through the vacuum table and wrapping jig shown in figure 9.

BEST MODES OF CARRYING OUT THE INVENTION Referring to the drawings, Figure 1 shows apparatus for laminating a sheet material onto a surface of the mineral or fibre based material or composite material. The apparatus is generally referenced 1 and has a number, preferably three, vacuum beds 2

which have perforated support surfaces 4 (perforations not shown in Figure 1). The

support surfaces 4 are in fluid connection with a vacuum pump (not shown) for producing

a vacuum between the vacuum bed and an impervious sheet material placed over the vacuum bed. A vacuum cleaner 3 and compressed air nozzle 5 are provided for cleaning materials used with the apparatus or the apparatus 1 itself. An oven 6 is also provided having heating means comprising infrared heater elements located in the area 8 of the oven as will be described in more detail below. The heater, although shown in Figure 1 in an elevated position relative to the vacuum beds 2, in use has wheels or rotating elements which are attached to runners located below the surface of the vacuum beds 2 so that the oven may be slid above the vacuum beds relative to the vacuum beds as will be described further below. The apparatus also has a controller comprising a micro processor and associated storage devices such as disc drive containing a magnetic disc or the like which has information relating to the process or processes carried out by the machine stored thereon for use by the controller. The processor and machine controls

are located in box 10 of the machine and this may also contain the vacuum pumps. A control panel is also provided to display the status of the machine to a user and to provide control switches for an operator to operate the machine. Foot operated switches 14 to operate the vacuum beds are also provided.

Figure 2 shows apparatus for dispensing sheet material generally referenced 16.

The apparatus comprises a member 18 for storage of a roll of sheet material to be

laminated to another material. The sheet material stored on roll 18 is unrolled by a user and draped over support member 20 so that it hangs vertically down in front of surface 22. A spray gun 24 is then used to spray a surface of the sheet material with a resin or adhesive stored in container 26. Pressure for the spray gun 24 is provided by compressor 28.

Referring to Figure 3 the apparatus 1 of Figure 1 is shown in cross section through line AA of Figure 1. The apparatus can be seen in more detail, in particular the

perforations 30 provided in the perforated support surface 4 of the vacuum bed 2. The perforated support surface 4 is supported in the vacuum bed by supports 32 which are provided in spaces under the perforated support surface so that they do not interfere with the fluid connection between the perforations 30 and the vacuum conduit 34 from the vacuum bed to the vacuum blower 36 which is connected to the vacuum pump.

Underneath the edges of the vacuum bed 2 are provided runners 38 which support wheels or rotatable members 40 of the curing oven 6. The wheels 40 are able to rotate within runners 38 so that the oven 6 can be slidably moved relative to the vacuum bed 2. The oven 6 has a number of infrared heaters 42 mounted on a support member 44 within the oven. The infrared energy heaters 42 provide substantially radiant energy

(approximately 85% at a wavelength of approximately 10,000 to 15,000 micro meters). The heating elements 42 are supplied with electric power from insulated element wiring

46. In use, articles such as wall panels or ceiling tiles which are placed above insulated wiring 46 receive some heat by convection from the heating elements 42 or the wall

panels or ceiling tiles which the elements heat on the perforated surface 4. This warming portion of the oven is referenced 45. A wall panel or ceiling tile 48 is shown in dotted outline on the perforated surface 4 of the vacuum bed. Figure 4 shows a wall panel or ceiling tile on perforated surface 4 of the vacuum

bed in more detail. It will be seen that the tile fits within the area of the perforated surface 4 thereby allowing a low density fluid impervious flexible high temperature cover

(not shown in Figure 4) to be placed over the tile and the vacuum bed so that a vacuum

may be established between the cover and the source of the vacuum so that a sheet

material located beneath the cover can be forced into intimate contact with a surface of the ceiling tile or panel.

A piece of sheet material 54 is shown in Figure 5 conforming to the contours of

a surface such as a decorative surface of a building tile or panel 52 in Figure 5. Such

a sheet material when adhered to the tile so as to be laminated thereto effectively refurbishes the tile by improving the appearance of the decorative surface and provides the tile with additional strength and durability and a washable surface which reduces future maintenance requirements.

In Figure 6 the ceiling tile or wall panel 52 comprises an embossed mineral fibre panel, for example, and a sheet of material 54 is shown in contact with the upper surface of the tile or panel and the cover 50 as described above with reference to Figure 4 is shown exerting force on the sheet material 54 due to the vacuum applied via the perforated support surface 4. The cover 50 preferably comprises a low density fluid

impervious flexible material such as a butyl rubber which may stretch to accommodate

the surface of the tile or panel 52. The tile or panel 52 in Figure 7 comprises a patterned fibrous plaster tile or panel for example, the fibrous plaster being indicated by the square shaded region 56. In

Figure 8 a flat or perforated metal tile or panel is shown having vinyl material adhered

to it to form a surface of the tile.

The apparatus described above is used to perform the following lamination

process. Firstly, a mineral or fibre based material or composite material such as a ceiling tile or wall panel which, for example, has been damaged or has a discoloured outer

surface and requires to be refurbished is selected and if necessary placed in the drying or preheating area 45 of the oven 6 (Figure 3). This step is only performed if the tile or

panel needs to be warmed up, for example, to remove any undesired contours which have formed in the panel or to dry it out. Also, the vacuum cleaner 3 or compressed air nozzle 5 may be used to clean the tile. The tile or panel is then placed on a vacuum bed 2 with its decorative surface uppermost away from the bed. A sheet of material which is to be laminated to the upper or decorative surface of the tile in order to improve the appearance of the tile so as to refurbish it, and strengthen it with a washable surface, is then unrolled from the roll dispenser 18 (Figure 2) and a side of the sheet material which has been unrolled is then sprayed with resin or adhesive using the spray gun 24. The

sheet material is then cut to an appropriate size which has sufficient area to cover the upper decorative surface of the tile or panel and the adhesive side is placed upon that

upper or decorative surface. A cover such as the cover 50 described above is then placed over the tile or panel and the sheet material so that the perforated support surface 4 of the vacuum bed is completely covered. If the operator has not already done so, the operator uses the operational control panel 12 to select the desired amount of vacuum and amount of temperature or length of time for which heat will be applied to the tile and the sheet to be adhered thereto. This may be performed automatically by the controller upon the operator entering the ceiling panel type and size and the sheet material which is to be adhered or laminated to the ceiling panel. The operator then uses the foot switch 14

corresponding to the appropriate vacuum bed to be used to apply a vacuum to the vacuum bed. The vacuum is produced between the cover 50 and the source of the vacuum which

forces the cover 50 about the vacuum bed and about the sheet material covering the ceiling tile or panel. The cover forces the sheet material to conform to the contours of

the upper surface of the ceiling tile so as to adhere the sheet material to the upper surface.

Before the vacuum is removed the oven is moved manually or by the controller

slidably into place above the vacuum bed 2 on which the ceiling tile is located and heat provided by the infrared heating elements is then applied for a desired time period to cure the adhesive between the sheet material and the ceiling tile or panel. Thus the sheet material is secured to the composite material while the sheet material is in a collapsed state. The use of infrared heating elements prevents damage to the materials during the

heating process. Once the resin or adhesive has been cured (which may take approximately 15-120 seconds or less), the operator then removes the cover 50 and uses a utility knife or the like to remove the excess sheet material about the edges of the ceiling tile so that the tile may be removed from the vacuum bed ready to be used once again. Alternatively, the excess material may be folded about the edges of the tile and secured to the rear surface with adhesive tape.

The material from which the perforated support surface 4 of the vacuum bed is made is preferably polytetrafluoroethylene (PTFE) since this has been found easy to clean of excess adhesive as it is self lubricating. The composite materials which may be refurbished using this process are many. Some include cardboard boxes for use in food transportation and storage, ceiling tiles, chair and stool seats, wall panels.

The sheet materials which may be used to refurbish composite materials using this

process include commercial fabrics, synthetic leathers, vinyl foils and PVC foils preferably of a thickness of 0.5 - 1.5mm. The adhesives used are preferably water based emulsions suitable for application by air pressure spray dispensers. However resins may

also be used.

Referring to figure 9 a wrapping jig generally referenced 60 comprising a frame 62 is shown mounted on perforated support surface 4.

The wrapping jig is shown in more detail in figure 10. Referring to figure 10,

the outer frame 62 of the wrapping jig is shown mounted on a base plate 64. Holes 66 are provided in the base plate 64 to allow the vacuum from the vacuum table 2 to be

provided within the frame. Crossbars 68 are provided within the frame to support the panel (shown by broken line 70) which is located above the wrapping jig, being supported by frame 62 and crossbars 68. The frame 62 has grooves 72 machined into the upper surface of frame 62. The grooves 72 provide venting means to allow the vacuum present within the frame to be present at the external upper surface of the frame for the purpose of laminating sheet material to the building panel or tile 70 as will be described further

below.

Referring to figure 11, part of the vacuum bed or table 2 together with the wrapping jig and a ceiling tile or building panel are shown in cross-section. The operation of the apparatus is shown with reference to figure 11. In use, the wrapping jig 60 is placed on the perforated support surface 4. The perforations 30 allow the vacuum from conduit 34 to be supplied to the table. When the base plate 64 is placed on the perforated support surface 4 of the vacuum table, apertures 46 in the base plate

communicate with some of the apertures 30 in the support surface to supply the vacuum

to the frame. Also, apertures 66 within the crossbars 68 of the frame allow the vacuum to communicate with the outer frame members 62.

After the wrapping jig or frame has been placed on the support surface of the vacuum table, a panel or tile such as a building panel or ceiling tile 70 shown in figure 11 is placed over the top of the frame 62. An adhesive or a resin is then applied to the

building panel, or to a sheet material which is to be laminated to the building panel. The

sheet material to be laminated to the panel may be a fabric or vinyl material or a woven material, for example, and the building panel is preferably a mineral or fibre based material, such as a fibrous plaster tile but could be any mineral or fibre based material such as a bench top, seat, desk or table top for example. The sheet material such as vinyl fabric material is then placed over the tile and around an edge 78 of the tile so as to cover edge surfaces and surfaces either side of the edge surface of the tile, comprising upper surface 79, end surface 80 and lower surface 81. The frame is constructed so as to allow the sheet material to be applied to the back, or lower surface 81 of the panel or tile around all the edges of the tile or panel. The material is then cut so that the part 82 thereof covers the outer frame 62 over the external entrance to grooves 72 in the frame. A partial vacuum is then applied to conduit 34. Sheet material 82 forms a seal with the frame 62 and thus the sheet material is forced into contact with the resin or adhesive and the tile outer surface, particularly the surfaces of the tile on and/or adjacent to edges 78 of the tile. Heat is then applied to the laminated construction to cure the resin or adhesive using infrared heaters 42 so that the sheet material is secured to the composite material while the sheet material is in a collapsed state. The vacuum is then released so that the excess sheet material 82 can be trimmed from the tile at point 84 and the tile can

be removed from the jig for reuse. Thus all the edges, the upper surface and part of the

lower or back surface of the tile are laminated with the sheet material. In order to allow

for easy removal of the tile from the jig, the external surfaces of the jig are preferably constructed from a self-lubricating plastic material such as polyethylene material and the frame work of the jig is preferably constructed from aluminium.

The method and apparatus described above for laminating sheet materials to composite materials ensures that the edges of the composite materials are laminated to the

sheet material and the back or underside 81 of the composite material for at least 20mm in from the edge is also laminated. This provides the advantages of additional strength and protection to the edges of the composite material. Furthermore, it adds significantly to the appearance of any panel or tile which is laminated in accordance with this method

and prevents composite material being chipped from the edges of tiles or coming away from the edges of tiles due to movement in a building for example. This is advantageous

as such material can be a health risk.

Apart from placing the tile on the vacuum table, applying the sheet material and removing the tile, all the other steps and methods may be performed automatically by the control apparatus 9 which may be used to, for example, select the desired amount of vacuum and amount of temperature or length of time for which heat will be applied to the tile and the sheet to be adhered thereto.

As well as being applicable to old panels, tiles or the like which are in need of refurbishment, the present invention can also be used with new panels or tiles such as gib

board, fibre glass or mineral fibre wall panels or ceiling panels for example where the wrapping of the edges of the panels stops loose particles coming away from the open edges.

The process of the present invention is also ideally suited for laminating coverings

onto other articles such as kitchen stool seats, table and desk tops for example, where it is required that the covering material is pulled around all edges and is secured to the

reverse side of the composite panel being covered. Also, the apparatus of the present invention enables wallboards of up to 3 metres x 1.5 metres to be laminated to sheet materials.

It will be seen that the invention, at least in the preferred form, provides a new

and effective method and apparatus for laminating sheet materials to mineral or fibre

based materials or composite materials for manufacturing new objects or for refurbishing old objects.

Claims (37)

1. A method of laminating a sheet material onto a surface of a mineral or fibre based material, said method comprising the steps of;

providing a resin or an adhesive on said sheet material or on said surface,

placing said sheet material on said surface so that said resin or adhesive is

provided substantially between said sheet material and said surface, placing a substantially impervious flexible cover over said sheet material, and

applying a partial vacuum between said cover and a vacuum source to force said sheet material into contact with said mineral or fibre based composite material to laminate

said sheet material to said surface.

2. A method as claimed in claim 1 wherein said step of placing said sheet material on said surface includes the step of placing said sheet material on a first surface and placing at least part of said sheet material about an edge of said mineral or fibre based material and onto a second opposite surface of said mineral or fibre based material so that at least some of said resin or adhesive is located between said sheet material and said second surface.

3. A method as claimed in claim 1 or claim 2 which includes the step of applying

heat to the laminated construction to cure said resin or adhesive.

4. A method as claimed in claim 3 wherein said step of applying heat is performed

before said vacuum is removed.

5. A method as claimed in claim 3 or claim 4 wherein said step of applying heat comprises the step of applying radiant energy to the laminated construction.

6. A method as claimed in any one of the preceding claims wherein said mineral or

fibre based material is a composite material.

7. A method of laminating a sheet material onto a surface of a mineral or fibre based

material substantially as herein described with reference to and as illustrated by the accompanying drawings.

8. Apparatus for laminating sheet material onto a surface of a mineral or fibre based material, said apparatus comprising a vacuum bed having a plurality of perforations through a material support surface of the bed, air being capable of being drawn through said perforations to form a partial vacuum,

an air impervious flexible high temperature cover of a size sufficient to cover all

said perforations in said vacuum bed, and

vacuum apparatus for establishing a partial vacuum via said perforations between said cover and the vacuum apparatus sufficient to at least force said cover into contact with said support surface.

9. Apparatus as claimed in claim 8 including a frame having venting means therein, air being capable of being drawn through said venting means to form a partial vacuum via said venting means between said sheet material and said vacuum apparatus sufficient to at least force said sheet material into contact with a first surface of said mineral or fibre based material and a second opposite surface.

10. Apparatus as claimed in claim 8 or claim 9 which includes heating means.

11. Apparatus as claimed in any one of claims 8 to 10 which includes control means

for controlling the vacuum applied to provide a desired amount of vacuum for the type of sheet material and mineral or fibre based material.

12. Apparatus as claimed in claim 10 or claim 11 wherein said control means also control the amount of heat and/or time for which heat is applied to the laminated

materials.

13. Apparatus as claimed in any one of claims 10 to 12 wherein said control means includes storage means which store information regarding the amount of vacuum to be applied and/or the time for which heat is applied to the laminated materials or amount of

heat to be applied to said materials for use by said control means.

14. Apparatus as claimed in any one of claims 10 to 13 wherein said heating means include means for warming a material by convection.

15. Apparatus as claimed in any one of claims 10 to 14 wherein the energy produced by said heating means is at least substantially 85% radiant energy.

16. Apparatus as claimed in any one of claims 8 to 15 wherein said bed is constructed

from a self lubricating material.

17. Apparatus as claimed in any one of claims 9 to 16 wherein at least a part of said frame is constructed from a self lubricating material.

18. Apparatus as claimed in claim 16 or claim 17 wherein said self lubricating material comprises polytetrafluoroethylene.

19. Apparatus as claimed in any one of claims 8 to 18 wherein said mineral or fibre based material is a composite material.

20. Apparatus for laminating sheet material onto a surface of a mineral or fibre based material substantially as herein described with reference to and as illustrated by the accompanying drawings.

21. A method of laminating a sheet material onto surfaces of a mineral or fibre based

material, said method comprising the steps of; providing a resin or an adhesive on said sheet material, or on one of said surfaces placing said sheet material on a first surface and placing at least part of said sheet material about an edge of said mineral or fibre material and onto a second opposite surface of said mineral or fibre based material so that at least some of said resin or adhesive is located between said sheet material and said second surface, and applying a partial vacuum between said sheet material and a vacuum source to force said sheet material into contact with said surfaces to laminate said sheet material to at least said second surface.

22. A method as claimed in claim 21 which includes the step of placing a substantially impervious flexible cover over said sheet material and applying the partial vacuum

between said cover and said vacuum source.

23. A method as claimed in claim 21 or claim 22 which includes the step of applying

heat to the laminated construction to cure said resin or adhesive.

24. A method as claimed in claim 23 wherein said step of applying heat is performed before said vacuum is removed.

25. A method as claimed in claim 23 or claim 24 wherein said step of applying heat comprises the step of applying radiant energy to the laminated construction.

26. A method as claimed in any one of claims 21 to 25 wherein said mineral or fibre

based material is a composite material.

27. Apparatus for laminating a sheet material onto a surface of a mineral or fibre

based material, said apparatus comprising a frame having venting means therein, air being capable of being drawn through said venting means to form a partial vacuum, vacuum apparatus for establishing a partial vacuum via said venting means between said sheet material and the vacuum apparatus sufficient to at least force said sheet material into contact with a first surface of said mineral or fibre based material and a second opposite surface.

28. Apparatus as claimed in claim 27 including a substantially impervious flexible cover for placement over said sheet material.

29. Apparatus as claimed in claim 27 or claim 28 which includes heating means.

30. Apparatus as claimed in any one of claims 27 to 29 which includes control means

for controlling the vacuum applied to said frame in order to optimise the amount of

vacuum applied for the type of sheet material and mineral or fibre based material.

31. Apparatus as claimed in claim 30 wherein said control means also control the

amount and/or time for which heat is applied to the laminated materials.

32. Apparatus was claimed in claim 30 or clairri 31 wherein said control means

includes storage means which store information regarding the amount of vacuum to be applied and/or for which heat is applied to the laminated materials or amount of heat to be applied to said materials for use by said control means.

33. Apparatus as claimed in any one of claims 29 to 32 wherein said heating means

include means for warming a material by convection.

34. Apparatus as claimed in any one of claims 29 to 33 wherein the energy produced by said heating means is at least substantially 85% radiant energy.

35. Apparatus as claimed in any one of claims 27 to 34 wherein at least part of said frame is constructed from a self lubricating material such as polyethylene plastic.

36. Apparatus as claimed in any one of claims 27 to 35 wherein at least part of said frame is constructed from aluminium.

37. Apparatus as claimed in any one of claims 27 to 36 wherein said mineral or fibre based material is a composite material.