Abstract:
A spacer adapted, in use, to space materials, (for example sheets of glass) comprising a spacer element having on at least one face an adhesive wherein at least a portion of the edge of said adhesive carrying face is adhesive free. The spacer is fabricated from a relatively flexible material so that the portion which does not adhere to the material being spaced (because there is no adhesive on that portion) can be bent from out of the plane of the spacer. Once the unadhered portion is so bent a finger hold is provided.

Description:
This invention concerns improvements in and relating to materials, particularly but not exclusively of the type used to space glass and other materials during handling storage and transportation, particularly those of sheet form. 
     BACKGROUND OF THE INVENTION 
     Glass sheets arrive from the manufacturers in stacks of sheets of one size in a purpose built frame. However, during subsequent processing and handling spacing elements are used to keep the individual glass element apart with a view to easing handling and avoid damage due to relative movement or foreign bodies being caught between sheets. 
     As many sets of spacers may be required during the overall process life of the glass spacers must be cheap to produce; and not damage the glass as well as offering suitable padding levels. Above all the spacers must be easily applied and removed. 
     A number of different materials can and have been employed as spacers. 
     Amongst the earliest techniques was the introduction of a piece of paper between the sheets. However, paper offers limited crush resistance or padding and is awkward to handle. 
     As an alternative the provision of spacers as a series of discrete blocks which are placed at various locations on the glass has been used. A number of such spacer types exist, such as cork and PVC composites or a foam pad. When applied without an adhesive on one side to hold the pad in position the spacer frequently and inconveniently falls off. When provided with an adhesive the spacer sometimes bonds too well and is difficult to remove, decreasing productivity. 
     SUMMARY OF THE INVENTION 
     It is an aim of the present invention to meet these objectives whilst providing a spacer which can easily be introduced to and removed from its location of use. 
     According to a first aspect of the invention we provide a spacer adapted, in use, to space materials comprising a spacer element the spacer element having on at least one face an adhesive wherein at least a portion of the edge of said adhesive carrying face is adhesive free. 
     In this way a finger or other means employed to remove the spacer can easily do so as a portion of the edge is easily liftable relative to the spaced element. 
     The spacer is preferably sufficiently flexible that a part of it (e.g. a non-adhesive peripheral portion) can be bent out of the plane of the remaining, bonded, part of it so as to assist in gripping the spacer to remove it. Thus a “fingerlift” edge portion is provided. 
     Preferably the adhesive is provided in one or more stripes. An easy manner for introducing the adhesive is thus allowed. Most preferably the stripes are substantially perpendicular to an edge of the spacer. This gives regular positioning of the adhesive on a series of spacers. 
     The adhesive may be provided in a central portion of the spacer, so providing a large amount of edge free. Alternatively, or additionally, the adhesive may follow one or more edges, leaving one or more other edges or portions thereof, free. 
     The adhesive carrying areas themselves may consist of a continuous or discontinuous layer of adhesive. Thus the adhesive may be provided as dots, cross-hatching or the like to give the desired degree of adhesion and level of adhesive use. 
     According to a second aspect of the invention we provide a method of manufacturing a plurality of spacers comprising: 
     a) forming the spacer material 
     b) applying continuous discontinuous adhesive to the spacer material 
     c) cutting the spacer material into a plurality of spacers, 
     wherein one or more of the cut edges of the spacer includes a portion of spacer material which is free of adhesive. 
     In this way the fingerlift function is achieved as a “dry edge” is provided. 
     Steps b) and c) may be reversed whilst achieving the same result. 
     Preferably each spacer generated has an edge portion without adhesive but a degree of wastage is acceptable. 
     Preferably the adhesive is applied in stripes. Most preferably the application is parallel to the direction of advancement of the spacer material through the adhesive applying stage. 
     The adhesive may be applied in stripes between three quarters and a fifth of the width of the spacer to be cut although the adhesive may be wider or narrower. An equivalent or larger or smaller width may be provided between adjacent adhesive stripes or adhesive free areas. The effect may be achieved by multiple stripes or other form of discontinuous adhesive (e.g. dots) 
     Whilst an adhesive may be applied to the spacer as a continuous covering alternatively it may be in a discontinuous form, such as a pattern, series of dots or strips which may aid the use or manufacture as well as reducing manufacturing costs. The use of discontinuous adhesives is particularly advantageous where it is desired to apply the spacer by means of semi-automatic or automatic dispensers as are currently employed on production lines or in other continuous manufacturing environments. 
     Particularly preferred type of adhesives are the pressure-sensitive types which will readily hold the component in place during use but will easily and cleanly remove from the glass and/or other material when no longer required. 
     The spacer may have its adhesive covered by protective release paper to aid manufacture of the pads and dispensing and eventual use/application of same. 
     By cutting spacer material into the required size during manufacture and using external glue to join adjoining sheets a spacer material or layers of a roll of spacer material temporarily, the product can economically be provided in easily handled form. 
     Alternatively the externally applied adhesive may be incorporated into the manufacture of the spacer material. Such an adhesive may be applied prior to or when cutting the spacer material to make rolls or sheets of spacers. 
     When supplied in rolls, the product may be provided in various lengths and widths as necessary to ease its use with specialist application equipment or by hand. Where such equipment is used, the dispensers themselves may serve to cut the spacers at the required size and/or apply them to the glass and or other materials. 
     Where a backing is provided the die may cut through the spacer material and leave the backing intact. 
     Preferably the die cuts through the spacer material and partly cuts the backing material providing a construction which allows lengths of product to be removed from a roll. 
     The partial cutting may comprise providing a cut at either side of the backing material. Alternatively, it may comprise providing perforations or cuts across the width of the backing material. 
     In another embodiment of the present invention there is provided a stack of two or more sheets of glass (or other material) wherein each sheet is separated by one or more spaces according to the first aspect of the invention. 
     In yet another embodiment of the present invention there is provided a sheet of material having a first and second face, the sheet having on at least one of the faces a number of stripes of glue, the sheet being adapted, in use, to be cut into spacers according to the first aspect of the invention. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     Embodiments of the invention will now be described, by way of example only, with reference to the drawings in which: 
     FIG. 1 shows an embodiment of a spacer according to the first aspect of the invention; 
     FIGS. 2 a  to  2   e  illustrates a number of other such embodiments; 
     FIG. 3 shows a prior art spacer in use; 
     FIG. 4 shows a section of sheet of spacers of the present invention; 
     FIG. 4 a  shows a section of a sheet of spacers of another embodiment of the present invention; 
     FIG. 5 shows a section of a roll of spacers ready for use; 
     FIGS. 6 a  and  6   b  show schematically the invention is use; 
     FIG. 7 shows a stack of sheet glass separated by spacer; 
     FIG. 8 a  shows an underneath view of a backing sheet according to the present invention; 
     FIG. 8 b  shows an underneath view of a different embodiment of the invention from that shown in FIG. 8 a ; and 
     FIG. 9 shows a schematic view of a further embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     As illustrated in FIG. 1, a spacer  1  is formed from a spacer element  3  together with an adhesive material  5 . 
     The spacer element  3  may be a single layer foam, cork or other material or consist a composite of one or more such materials. 
     By providing a discontinuous adhesive and/or a stripe of adhesive  5  dry areas  7  are provided around the edge of the spacer  1 . Thus a finger could easily lift edge portions  9 ,  11  and peel off the spacer whilst otherwise the adhesive layer  5  maintains the spacer&#39;s position. The spacer is flexible and so its dry edge  7  can be lifted up, whilst adhesive region  5  is still bound to the glass. If means other than fingers (e.g. blade) are to be used to remove the spacer, the free edge also assists in their insertion. 
     FIGS. 2 a-c  illustrate produce spacers  1  (e.g. spacers for sheet glass) having stripes of adhesive  5  in the manner of FIG.  1 . The variation in position of the stripes reflects variation in the centring of the stripe or the spacer relative to the cutting but demonstrates that, even so, free edges  9 ,  11  are generated. 
     FIGS. 2 d-e  illustrate alternative patterns of adhesive  5  whilst still giving free edges  9 ,  11 . 
     Preferably the adhesive layer  5  is a pressure sensitive self adhesive which is readily removable from glass. If desired a release paper layer or other backing sheet may be provided over the adhesive layer  5  to isolate the adhesive during storage. 
     To aid in storage, and also in subsequent deployment of the spacers it is desirable that they be cut through to at least some extent during formation. Thus dies stamp or other means can be used to cut the material of the spacers into blocks of the desired size for subsequent use. Ideally the material is cut completely through or only retained together by means of a relatively small proportion of the material. This relatively small portion can be broken when the element is needed for use. 
     The prior art shown in FIG. 3 shows a spacer  201  in situ on a section of glass  202  which is to be spaced from a further section of glass (not shown). The spacer  201  comprises a block of foam-like material  203  which is held in position on the glass by means of an adhesive layer  204 . 
     In use the spacer  201  is taken from its storage position and a layer of paper backing is removed to expose the layer of adhesive  204 . The adhesive  204  is then brought into contact with the glass  202  and is retained in position relative to it by adhesive action. The second member of glass is then brought into contact with the spacer  201  potentially resulting in the spacer  201  being compressed by the weight of glass. 
     Once the glass has been moved to the next location in which it is to be processed, cut or otherwise used, the glass members are separated and the spacers  201  removed. If any adhesive  204  remains on the glass it is desirable that it can be readily removed by conventional solvents and/or cleaners. 
     It can be difficult to prise off a prior art spacer, especially if it has been compressed for some time by the weight of a stack of sheets of glass. 
     FIGS. 4 and 4 a  show parts of a sheet of spacers  210  produced in accordance with the present invention. The spacers  210  are manufactured on a backing sheet  220 . The backing sheet  220  is fed into the manufacturing process and the foam spacer element forming material is introduced onto this backing sheet  220  in the required amount to form the spacer element  210  of the required thickness. As the backing sheet  220  is introduce to the material, strips of adhesive  213  can be introduced between the two. Alternatively (as shown in FIG. 4 a ) strips of adhesive can be provided on a side of the material opposite the backing sheet. The strip of adhesive may have previously been applied to the release paper or backing sheet or laminated onto the spacer material. 
     It is possible that heat treatment and/or die cutting could be used to further form the spacer element  210 . In this way a sheet is formed which requires cutting into the desired size for the given space application. A number of sheets may be stacked upon one another prior to the cutting stage and/or after cutting. Cutting is effected by way of dies which are designed to cut through the material in total or leave only the top and/or bottom intact or perforated. Sheets produced by one way are illustrated in FIG.  4  and provide a readily handleable way of presenting the spacers. 
     FIG. 5 shows the sheet of spacers of FIG. 4 in a roll. 
     By providing a layer of adhesive  212  on the spacer materials  210  but without providing a release paper covering for this external adhesive, then sheets  231  can be stacked or, alternatively, as shown in FIG. 5, they can be rolled with the adhesive layer  212  ensuring that the coherence of the stack or roll is maintained. Thus a roll of spacers  210  one spacer wide can be cut but the roll will stay together due to the adhesive interaction between adjoining spacers and/or the joined nature of one or more of the layers. 
     I could also use the invention in relation to plastics glazing frames such UPVC window frames (or door frames) or other materials/parts, perhaps sheets of metal. These also need spacing from each other in transit and experience similar problems, including difficulty in removing spacers. The protection I am seeking includes spaced frames, and the application to the invention to spacing frames. It also includes the application of the invention to: glazed units—frames with glass in and protection during transit and installation; sheets of glass prior to and post processing; glazed units; window frames; window frames with units in; other materials including metal formed parts (e.g. metal partitioning, metal dies, other metal and non-metal components). 
     As shown in FIG. 8 a  cuts  240  may be provided so that backing/strip release paper can easily be torn in strips from a roll. That is the strip/release paper may tear between the cuts. The cuts  240  are provided level one another at opposite sides of the backing strip/release paper. (Alternatively, they may not be level with one another). 
     As shown in FIG. 8 b  the backing strip/release paper has been perforated width ways  250  so that it can easily be torn in strips (perhaps from a roll as shown in FIG.  5 ). 
     As shown in FIG. 7 a number of sheets of glass  260  can be separated by a number of spacer elements  1 . 
     In one embodiment the spacers are provided in a sheet or roll form with stripes of adhesive between a foam spacer material and a release paper. This is shown in FIG. 9 wherein the spacers  270  are shown by each rectangle, the stripes of adhesive  272  by the shaded stripes and the adhesive free areas at  273 . Cuts  274  are provided at either side of the release paper in a similar manner as in FIG.  8 a. It should be noted that the cuts do not protrude into the adhesive stripes  272 . It has been found that if the cuts do protrude into the adhesive the release paper may tear in an uncontrolled manner and makes the spacer difficult to remove from the release paper. (Of course, in other embodiments the cuts may be made to protrude into the adhesive stripes).