AU2009201287A1 - Laminated method and product - Google Patents

Description

P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: LAMINATED METHOD AND PRODUCT Applicant: Joseph John Hunter and Ronald van der Sterren The following statement is a full description of this invention, including the best method of performing it known to me: 1 2 LAMINATED METHOD AND PRODUCT The present invention relates to a method of laminating a fibre board or sheet, 5 and to a laminated product. The present invention has been developed principally in relation to fibre board products, such as chipboard or medium density fibre board (MDF). It will be convenient to describe the invention in relation to that application, although it is to be appreciated that the invention is not restricted to those types of boards. 10 A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was, in Australia, known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims. 15 Fibre board is widely used in the furniture industry, such as for desks, tables, benches, doors, drawers and shelving. Fibre board is used because it has consistent properties, such as density and hardness, it is easy to shape or fashion, and it is generally less expensive than virgin timber. However, fibre 20 board generally requires a paint or laminate film to be applied at least to the visible surfaces of the furniture for aesthetic reasons and for protective purposes. Painting of fibre board generally gives the best aesthetic appearance, although 25 laminate film is less expensive to apply and often provides a better protective surface. The drawback with lamination is that the film can delaminate from the fibre board. Manufacturers of laminated fibre board have previously applied adhesive 30 laminate directly to one surface of the board. This can result in acceptable adhesion between the fibre board and the film, although the consistency of adhesion varies and for most laminators, the risk of delamination by this manufacturing process is too great. In an attempt to improve the adhesion between laminate film and the fibre board, manufacturers often sand the Wuile\AndreMComples\Lamnated Method and Produtadoc 3 surface of the fibre board to which the film is to be adhered, to provide a smooth surface. This is thought to decrease the likelihood of delamination. Fine sanding for a significant period is considered to give the best result. Nevertheless, delamination still occurs, with the problem being particularly 5 evident in regions of high humidity, or in regions where there are significant changes in humidity from day to day or week to week. One of the problems thought to contribute to delamination of the film from sanded board, is the residue dust that is left following sanding. That dust 10 usually is fine and is difficult to remove. The residue dust is though to affect the quality of adhesion between the film and the fibre board. The dust can be removed by blowing high pressure air over the sanded surface prior to application of the film, or by wiping the surface with a moist cloth, but both approaches add steps and therefore time and expense to the laminating 15 process, and yet the amount of dust removed from the surface is not usually the entire amount. This is particularly the case for the approach which employs high pressure air, because while dust is lifted from the surface by the high pressure air, a portion of the lifted dust often resettles on the fibre board surface before the film is applied. Moreover, if a moist cloth is employed, care 20 must be taken to ensure that the entire surface is wiped, while additionally, the fibre board must be dried before the film can be properly adhesively applied. Thus, each approach adds a further step to the manufacturing process, yet neither approach satisfactorily consistently removes all of the dust that occurs as a result of the sanding process and so the perceived advantages of sanding 25 are reduced. Accordingly, delamination still occurs in sanded board, despite the extra efforts made to reduce or eliminate it. Delamination of film causes significant problems in the furniture industry. Delamination often occurs within months, or sometimes even within weeks of 30 manufacture, so that often the affected board is only recently installed and replacement often requires attendance at the premises of the installation. Therefore, replacement of delaminated board can be costly, in particular if delamination occurs again in the replacement board, at which point the W.MueAndreeCompletes\Lmnated MMh a Pmducdoc 4 customer understandably might demand non-laminated board, such as painted board. It is an object of the present invention to provide an alternative method of 5 lamination that overcomes or at least alleviates problems or drawbacks associated with the prior art. According to the present invention there is provided a method of laminating fibre board, including: 10 (i) treating a surface of the board to be laminated either by embossing the surface, etching the surface, or by removing a layer equal to or greater than 0.1mm from the surface to expose the open fibre of the board beneath the surface layer; (ii) applying an adhesive backed laminate film to the treated surface. 15 The step of embossing, etching or of layer removal is such as to increase the depth of penetration of the adhesive of the laminate film into the board, so that there is better purchase between the film and the board surface to which the film is applied. By embossing or etching the surface, the surface can be 20 formed at a microscopic level, to have an irregular profile of varying depth. This contrasts with prior art surfaces in which the board surface is much smoother, so that adhesive penetration is less. This is more so the case where the board surface is sanded in accordance with prior art teaching, so that the depth of surface variation is reduced rather than increased. 25 By removing a surface layer of the board, board fibres below the surface become exposed and the adhesive intermingles with the fibres for stronger adhesion compared to the adhesion that is achieved with surfaces of the prior art. In effect, removal of the surface layer has the same effect as embossing 30 or etching, such that the profile of the surface becomes irregular and of varying depth. It is to be noted that fibre board is manufactured by pressing, usually under significant pressure, so that fibres in the outer surfaces are flattened and the surface is generally planar. By removing the outer surface layer of the board, the fibres below the surface become exposed and are not restrained in W:uue\Andrew\Completes\Lam1nated Method and Produd doc 5 the same manner as the surface layer fibres. The fibres therefore extend at angles that allow for purchase with the adhesive in a manner not available with the flattened surface fibres. 5 Moreover, in some fibre board, the fibre density is less inboard of the outer surfaces of the board, so that removal of the surface layer of the board exposes a less dense section of the board. Such a section has much greater depth variation because of the more sparse population of fibres and so again, adhesive purchase is improved. 10 The invention thus provides for surface treatment of fibre board to form a surface which is better able to adhere to a laminate film than prior to the treatment. Testing has shown that boards formed according to the invention have improved adhesion between the board and the laminate film and are less 15 likely to suffer delamination, even in humid environments. Embossing a board surface can involve pressing or rolling the board, with the press or roll being formed to penetrate the board surface to effectively roughen the surface. In other words, the surface becomes a textured or grained 20 surface. Advantageously, embossing can be included as part of an existing manufacturing step in the manufacture of fibre board products, such as those that include a melamine layer on one side thereof. The melamine layer is 25 usually applied by pressing and therefore the pressing operation can be modified so that the opposite side of the board to which the melamine layer is applied is embossed as the melamine is pressed onto the opposite surface. Thus, the only change to the existing manufacturing process for such board is to modify the press surface that engages the opposite side of the board, to 30 include an embossing surface, so that simultaneously with application of the melamine layer, the opposite surface is embossed. The depth to which the surface is embossed or penetrated can be quite small, to the extent that it is not evident to the eye. Thus, the depth of penetration W:\ulie\AndreACrplates\Laminated Method and Product.doc 6 can be in the order of 0.1mm,, although greater penetration is acceptable. The pattern of embossing can take any suitable form. What is required is that the surface prior to embossing is changed from a satin or smooth surface to a textured or grained surface. 5 Etching the fibre board surface produces a similar result to both surface layer removal and embossing, but by a different process. Any suitable etching process can be employed. 10 It is preferred that the entire surface which is to be laminated is treated by embossing, etching or surface removal. It is however acceptable in certain circumstances that the board surface be treated and the board edges be left untreated. 15 It could also be that the surface is treated by a combination of two or more of embossing, etching and surface layer removal. For example, the untreated surface of the board could be firstly fully embossed and thereafter the surface could be subject to routing for the purpose of applying a recessed pattern to the surface. The routing thus removes a surface layer following embossing. 20 Moreover, some sections of the surface might be more easily treated by layer removal than by embossing or etching or vice versa, so that the most appropriate treatment is selected depending on the circumstances. Removing a layer of the board surface can be completed by grinding or routing 25 or other suitable process. The depth of the layer which is removed, preferably is in the order of about 0.1 mm to 0.4 mm, however the depth of removal can be dependent on the type of board. As indicated above, in some board, the middle section of the board is less dense than the sections on either side, i.e. upper and lower sections and the preference is to remove sufficient depth that 30 the less dense layer is exposed for adhesion by the laminate film. The laminate film which is applied to the fibre board treated in accordance with the discussion above, can be of any suitable form and can be prior art film which is already employed. It is preferred however, that the adhesive is an W.uue\AndredCompletes\Laminaed Metod and Prduc.doc 7 adhesive membrane which is applied to the rear surface of the film prior to application of the film to the board. Advantageously, adhesive membranes of this kind can assist to create a moisture barrier between the board and the film, so contributing to a reduction in the likelihood of delamination. 5 It is to be noted that it is the adhesive that penetrates into the treated surface of the board, so that the invention does not affect the appearance or surface feel of the fibre board laminated according to the invention. Thus, to the untrained eye, board laminated according to the invention is substantially 10 identical to prior art board, with the exception that the likelihood of delamination is reduced. Advantageously, this means that adoption of the present invention results in no change to the external appearance of laminated fibre board 15 For a better understanding of the invention and to show how it may be performed, embodiments thereof will now be described, by way of non-limiting example only, with reference to the accompanying drawings. Figure 1 shows a fibre board section according to the prior art from which a 20 laminate film has been stripped. Figure 2 shows a fibre board section according to the present invention from which a laminate film has been stripped. 25 To illustrate the invention, Figures 1 and 2 show a section of fibre board to which a laminate film has been applied and then stripped. The board 10 of Figure 1 is a prior art board, while the board 20 of Figure 2 is one which has been treated according to the invention. Thus, in relation to each of the boards 10 and 20 of Figures 1 and 2, a film has been applied to the board by an 30 adhesive. After allowing the adhesive to cure, the film has then been stripped from the board. In each of the figures, the dark areas represent areas of maximum adhesion between the film and the board. In those areas, upon stripping of the film from W.A ndrew\CompleteLaminated Method and Poductdoc 8 the board, a portion of the actual surface of the board has come away with the film. Areas of the boards in the figures which are lighter in colour, are areas in 5 which the film has bonded to the board with less strength than compared to the darker areas. In those lighter areas, either no portion of the actual surface of the board has come away with the film, or only a small portion of the board has come away with the film. Where the bond strength is low between the film and the board, delamination is most likely under delaminating conditions. 10 It can be seen that the majority of the surface of the board 10 is of a lighter colour. In relation to the board 20, it is clearly evident that the board includes a much 15 greater proportion of dark area compared to the board 10. This indicates that the film has adhered to the board 20 more securely than to the board 10. In fact, the adhesive of the film which was stripped from the board 20 was able to adhere with greater purchase to the board 20 by an embossing treatment that was applied to the surface of the board 20 prior to the application of the 20 adhesive film. A similar result has been achieved in board which has had a thin surface layer removed as described earlier, rather than having been treated by embossing. Figure 2 is illustrative that the laminate film which was applied to the board 20 25 was more securely applied to the board 20 compared to the film that was applied to the board 10. The elevated security of fixing results in a significantly reduced likelihood of delamination of film from the fibre board. Testing of laminated fibre board manufactured according to the invention has shown that the reduced delamination occurs even in areas of high humidity or in varying 30 humidity. As indicated earlier, other than the step of embossing, etching or surface layer removal, in other aspects, laminated fibre board produced according to the invention is produced in the same manner, or a very similar manner, to prior art W:\utie\AndreMCmpletes\Laminad Mefld and Pmductdoc 9 laminated fibre board. Thus, the process steps of the prior art are generally included in the production of laminated fibre board according to the invention, with the addition of the embossing, etching or surface layer removal step. As noted above, the embossing step can be conducted as part of a pressing step 5 in the production of fibre board, such as melamine coated fibre board. The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or 10 additions which fall within the spirit and scope of the above description. W:ue\AndreAComplaes\Lamiad Methd ad PmducIdoc

Claims (11)

1. A method of laminating a fibre board, including: (i) treating a surface of the board to be laminated either by 5 embossing or etching the surface, or by removing a layer from the surface to expose the board beneath the layer; (ii) applying an adhesive backed laminate film to the treated surface.

2. A method according to claim 1, wherein surface of the board to be 10 laminated is treated by removing a layer from the surface of a thickness of about between 0.1mm to 0.4mm

3. A method according to claim 2, wherein surface of the board to be laminated is treated by removing a layer from the surface of a thickness of 15 about 0.4mm.

4. A method according to claim 1, wherein the surface of the board to be laminated is treated by embossing the surface, with the embossing being applied in a pressing operation. 20

5. A method according to claim 1, wherein the surface of the board to be laminated is treated by embossing the surface, with the embossing being applied by a pressure roller. 25

6. A method according to claim 4 or 5, wherein the depth of embossing is about between 0.1mm to 0.4mm.

7. A method according to claim 4 or 5, wherein the depth of embossing is about 0.1mm. 30

8. A method according to anyone of claims 1 to 7, further including applying an adhesive membrane to the laminate film and then applying the laminate film to the treated surface of the board with the adhesive membrane in contact with the treated surface. W:\uLLowrewACmpletes\Laminated Method 2nd Produc.doc 11

9. Laminated fibre board formed according to the method of any one of claims 1 to 8.

10. A method substantially as herein described. 5

11. A laminated fibre board substantially as herein described. WXuIeAnriAr CompletesUMinated Method aW PMductdoc