Patent Publication Number: US-2009233034-A1

Title: Tiling adhesive application system

Description:
This invention relates to a tiling adhesive application system, particularly (but not exclusively) suitable for the tiling of walls and floors. 
     The usual technique for applying tiling adhesive to a surface to be tiled is to employ a hand-held spreader tool having a blade with a plurality of grooves along one edge. That tool, or perhaps another spreader, is loaded with adhesive from a container thereof and then that adhesive is spread over an area to be tiled, in order to have on the surface a layer of adhesive of more or less uniform thickness. The notched edge of the spreader is then used to create a series of generally parallel beads of adhesive extending across that area, with each bead being of essentially the same height and width. Once done, tiles are pressed into engagement with the beads of adhesive, with the appropriate gaps between the adjacent tiles. 
     The above technique suffers from the disadvantage that both the spreader and the exterior of the container tend to become coated in adhesive and so most inconvenient to use. Further, adhesive is likely to fall from the spreader both as the spreader is being moved from the container to the surface to be tiled, and also during the course of spreading the adhesive over that surface. In addition, the technique is relatively slow to perform in that three separate steps are required, being the loading of the spreader from the container, the application of a uniform layer of adhesive to the surface and then the scraping of excess adhesive to leave the beads on the surface. The third step wastes a significant quantity of adhesive, leading to increased costs. 
     It is also known to dispense tiling adhesive from a tube thereof and having a nozzle, so that a bead of adhesive may be created directly on the surface to be tiled, or perhaps on the reverse face of a tile. Further, it is also known for the nozzle to have a plurality of outlets, such that a plurality of beads are formed simultaneously on the surface to be tiled or on the reverse face of a tile. Though this technique generally involves less wastage and is not so messy to perform, it is not particularly convenient when a large area is to be tiled. An additional disadvantage is that only a relatively small volume of adhesive can be contained within the tube and moreover blocking of the nozzle frequently occurs. 
     It is a principal aim of the present invention to provide an application system for tiling adhesive which is both easy and convenient to perform, minimises wastage and moreover reduces the time required for the tiling of a given area. 
     According to this invention, there is provided a tiling adhesive application system comprising a backing sheet carrying a plurality of beads of adhesive in a generally parallel array extending across the sheet, the backing sheet being peelable from the beads of adhesive following the application thereof to an area to be tiled or to a tile to be adhered to an area, while the beads are still carried by the backing sheet. 
     It will be appreciated that with the system of this invention, a backing sheet is pre-loaded with beads of adhesive of a suitable cross-sectional area and spacing for the purpose of adhering tiles to a surface. The beads of adhesive are applied to the surface to be tiled (which term is used herein also to refer to the reverse face of a tile, for a case where the adhesive is applied to that face of a tile rather than the surface to be tiled) by pressing the backing sheet carrying the beads of adhesive into engagement with the surface. Then, the backing sheet is peeled away so leaving the beads of adhesive on the surface, whereafter tiling may proceed in the conventional manner. Thus, there should be no wastage of adhesive with this system which moreover is rapid and easy to perform. 
     Preferably, the surface of the backing sheet on which said beads of tiling adhesive are carried is treated to give the backing sheet release properties with respect to the tiling adhesive. This will permit easy peeling of the backing sheet once the beads have been pressed into engagement with the surface to be tiled. 
     In order to maintain the characteristics of the tiling adhesive as manufactured, it is highly preferred that a release sheet is laid over the faces of the beads remote from the backing sheet. Such a release sheet advantageously is bonded to the backing sheet around the edges thereof. To that end, the backing sheet preferably has an upstanding lip around the edges thereof, to which the release sheet is bonded. Conveniently, that lip may have an out-turned margin to which the border region of the release sheet is bonded or sealed. 
     In a particularly preferred embodiment, the backing sheet is provided with a series of grooves extending thereacross, one bead of tiling adhesive being disposed in each groove respectively. Such grooves should be arranged in a parallel array, with a spacing equal to that required for the spacing of the beads of adhesive when applied to a surface to be tiled. Further, the depth of such grooves should be substantially equal to the required height of the beads of adhesive. 
     A backing sheet with grooves as described preferably is resistant to crushing in a direction substantial normal to the general plane of the backing sheet, in order to allow a plurality of such backing sheets carrying adhesive to be stacked one upon another, for transport and storage. Thus, the backing sheet may be substantially rigid and conveniently is formed from a sheet of plastics material, by a moulding operation such as vacuum forming. In this case, the release sheet conveniently comprises a relatively thin sheet of plastics material or a foil, hermetically sealed to the backing sheet but peelable therefrom, in order to form a closed pack which may easily be opened when required for use. 
     Preferably, the backing sheet is of rectangular outer shape and has outer dimensions corresponding to a selected one of conventional tile sizes, whereby the application of the beads of adhesive of the application system to a surface to be tiled allows a single tile to be adhered to that surface. Of course, it would instead be possible to use such a system to apply adhesive to the reverse face of a single tile and then to press the tile to the surface to be tiled, in the required position. In either case, the length of each bead of adhesive preferably is slightly less than the width of the conventional tile to be adhered to a surface by means of the beads of adhesive. 
     As an alternative to the above, the beads of adhesive may be laid lengthwise along a web of backing sheet which is then wound into a roll, though possibly with a release sheet laid over the beads of adhesive before the winding operation. Then, a required length of the backing sheet may be cut from the roll and the beads of adhesive applied to a surface to be tiled, whereafter a plurality of tiles may be adhered to that surface. 
     It is preferred that the backing sheet is of a transparent material and conveniently plastics. This aids the application of the backing sheet carrying the tiling adhesive to the required area to be tiled, or even to a tile, in the event that the tile is slightly smaller than the backing sheet. It will also assist cutting of the application system for tiling at the edge of an area to be tiled, or if tiling is to be performed around an obstruction. 
     Conventional tiling adhesive intended for application to a surface to be tiled either by a spreader or dispensed from a tube has a relatively low viscosity and, before application to a wall, is flowable to a limited extent. On application of the adhesive to a surface to be tiled, moisture is drawn from the adhesive and so the adhesive then tends to stay where applied. By contrast, it is preferred that the adhesive employed with the tiling system of this invention is significantly more viscous (or “stiff”) than such conventional tiling adhesive, in order that the beads may stay intact as deposited on the backing sheet. This may be achieved by adding a percentage of a chemical that thickens the adhesive, such as a polyacrylic rheology modifier. Also, the composition may include a component to increase the tackiness thereof, such as those products known as AcResin or Acronal. 
     The composition of the adhesive preferably is such that though initially relatively viscous, the adhesive rapidly becomes less so following the application thereof to a surface. This could be achieved by an appropriate chemical composition for the adhesive, so that on release of the adhesive from a sealed pack the viscosity reduces by contact with air. Another possibility would be to contact the adhesive with water to reduce its viscosity. This could be done by spraying the beads of adhesive whilst still carried by the backing sheet but before application of the beads to a surface, or following the application of the adhesive to a surface, for example by using a fine water spray. Another possibility for a case where the beads of adhesive are applied to the reverse face of a tile would be to dip the tile into a container of water. 
    
    
     
       By way of example only, various specific embodiments of tiling adhesive application system of this invention will now be described in detail, reference being made to the accompanying drawings in which: 
         FIG. 1  is an isometric view of the preferred embodiment of tiling adhesive application system, with the release sheet partially peeled; 
         FIG. 2  is an end view, partly in cross-section, of the system of  FIG. 1 ; 
         FIG. 3  is an isometric view of the underside of the system of  FIG. 1 ; 
         FIG. 4  illustrates use of the tiling adhesive application system; 
         FIG. 5  shows an alternative tiling adhesive application system; 
         FIG. 6  shows a tiling adhesive application system intended for use with octagonal tiles; and 
         FIGS. 7A and 7B  are respectively isometric and end views on yet another embodiment of tiling adhesive application system. 
     
    
    
     Referring initially to  FIGS. 1 to 3 , there is shown a first embodiment of tiling adhesive application system. This comprises a backing sheet  10  of a relatively hard plastics material pre-formed—for example by a vacuum moulding technique—to have a series of parallel troughs  11  or grooves extending across a face of the backing sheet. Each trough  11  is of generally semi-circular shape and extends parallel to opposed first and second edges  12  and  13  of the backing sheet, from locations adjacent but spaced from opposed third and fourth edges  14  and  15 . In this way, there are margins  16  around the sheet, adjacent each edge  12  to  15 . 
     Contained in each trough  11  is pre-mixed tiling adhesive  17 . The trough is substantially filled with the adhesive both for the full length of the trough and the full depth thereof. A release sheet  18  overlies the face of the backing sheet  10  into which the troughs open and is sealed to the margins  16  such that the adhesive  17  is in an hermetically-sealed environment. As shown in  FIG. 1 , the dimensions of the release sheet may be slightly smaller than those of the backing sheet. In the alternative, the release sheet may have essentially identical dimensions to those of the backing sheet or may be slightly larger, in order to allow grasping of the release sheet, to permit it to be peeled away from the backing sheet, as shown in  FIG. 1 . Yet another possibility would be to provide one or more tabs on the release sheet, projecting beyond the edges of the backing sheet and manually grippable to facilitate peeling away of the release sheet. 
     Typically, the backing sheet is made from transparent PVC or a similar plastic which readily lends itself to forming as shown in the drawings. The release sheet may also be of PVC or could be of another suitable grade of plastics material which may be heat-sealed to PVC. Depending upon the plastics material employed for the backing sheet and release sheet, as well as the characteristics of the adhesive, the surfaces of the backing sheet and release sheet which contact the adhesive may be treated in order to minimise the likelihood of the adhesive adhering thereto. 
     The adhesive contained within the troughs  11  may be similar to conventional tiling adhesives though it is preferred that the adhesive is relatively more viscous (or stiff) than conventional adhesives. This will resist the adhesive within the troughs moving to one end of the troughs, in the event that the packed adhesive is stacked on edge. An example of a suitable tiling adhesive is a mixture of about 1% Rheovis ATX (a highly effective associative polyacrylic rheology modifier) and about 3% Acronal (a tackifier) with the balance being a conventional tiling adhesive. 
       FIG. 4  illustrates the use of the tiling adhesive application system, to adhere rectangular tiles to a wall, each tile being of essentially the same dimensions as the backing sheet of the application system. Tiles  20  have already been adhered to wall  21  with the appropriate gaps  22  between the tiles, created by X-shaped separators  23 . A patch of adhesive  24 , consisting of parallel beads  25  of adhesive has already been applied to the wall ready for the next tile to be laid in the bottom row thereof. A further patch  26  of adhesive is shown being applied using the application system of this embodiment. 
     The adhesive is applied by peeling away the release sheet  18  from the backing sheet  10  of an application system and discarding that release sheet. The exposed surfaces of the beads of adhesive are wetted with a fine spray of water in order that the viscosity thereof is reduced and then the backing sheet is offered to the wall  21  at the required location. The backing sheet has the overall dimensions of the next tile to be laid and so can be used to assist positioning on the grid pre-marked on a wall, for the tiles. Once at the right position, pressure is applied to the backs of the troughs  11  so as to press the adhesive into engagement with the wall. Thereafter, as shown in  FIG. 4 , the backing sheet is bent away from the wall so as to come free of the beads of adhesive, whereafter the backing sheet is discarded. 
     By having a transparent backing sheet, positioning of the backing sheet is assisted. Moreover, before the release sheet is peeled away, the pack may be cut as required, for example when tiling to an edge or if the tiling is to go round an obstruction. 
     Though  FIG. 4  shows two patches of adhesive applied to a wall, more usually a single patch would be applied and then a tile presented to that patch. This prevents the adhesive drying too much by absorption of moisture into the wall. Further, it greatly assists cleanliness in working. 
       FIG. 5  shows an alternative embodiment of tiling adhesive application system using much the same principles as has been described above. However, in the embodiment of  FIG. 5  the backing sheet is in the form of an elongate web  28  with troughs  29  extending parallel to the length of the web. Though such a web could be provided with a peelable backing sheet, preferably it is wound into a roll such that the reverse face of the backing sheet serves as a release sheet for the next turn and protects the adhesive from drying out. When the system is to be employed, a required length is cut from the roll and is applied to a wall in the required location, after wetting with a fine spray if required. Such a system may be employed to allow the application of adhesive for a plurality of tiles, at the same time. 
     Instead of applying the adhesive directly to a wall, it may be applied to the reverse face of a tile.  FIG. 6  shows an embodiment of tiling adhesive application system which may particularly lend itself for use in this way, with octagonal shaped tiles. The backing sheet  31  has an octagonal overall shape with seven troughs extending thereacross, each substantially filled with adhesive  32 . A correspondingly release sheet  33  is sealed to the margins of the backing sheet  31  but can be peeled away as shown in  FIG. 6 , to permit wetting of the adhesive followed by the application of the backing sheet to an octagonal tile. Once pressure has been applied to the reverse face of the backing sheet to press the adhesive on to the tile, the backing sheet may be lifted away as has been described above with reference to  FIG. 3 . 
       FIGS. 7A and 7B  show an alternative embodiment of tiling adhesive application system. Here, there is a substantially rigid planar backing sheet  35  and a similarly formed release sheet  36  with beads  37  of tiling adhesive laid between the sheets  35  and  36 . A strippable edge band  38  is bonded to the edge margins of both sheets  35  and  36  and is substantially rigid in the direction perpendicular to the plane of sheets  35  and  36 , so as to hold the sheets at the required spacing. The edge band  38  includes a tab  39  whereby the end of the band may be pulled away from the sheets  35  and  36 , around the entire peripheries of those sheets. Thereafter one of the sheets  35 , 36  may be peeled away from the beads of adhesive. Once done, the application of the adhesive may proceed as has been described above with reference to the first embodiment.