Abstract:
A method of producing a succession of self-adhesive labels carried on a backing of release material including the steps of; a) providing an elongate web comprising a self-adhesive support web having a backing of release material; b) die-cutting and removing from the backing of release material a succession of portions of the support web; c) adhering a succession of multilaminar label portions to the succession of intermediate parts of the support web; and d) adhering a succession of portions of a self-adhesive overlaminate to the upper surface of the succession of multilaminar label portions so that each portion of the overlaminate substantially covers the respective multilaminar label portion and a respective portion of the backing of release material which is adjacent to the respective multilaminar label portion, the second portion of the upper surface of each intermediate part of the support web being left substantially uncovered by the overlaminate.

Description:
This application is a division of application Ser. No. 09/175,367, filed on Oct. 20, 1998, now U.S. Pat. No. 6,306,476. 
    
    
     BACKGROUND TO THE INVENTION 
     1. Field of the Invention 
     The present invention relates to self-adhesive labels and to a method of producing self-adhesive labels. In particular, the present invention relates to self-adhesive labels of multilaminar construction in which the label incorporates a booklet or folded sheet so as to provide a large surface area for carrying printed information which is greater than the surface area of the footprint of the label. The labels of the present invention have particular application in the labelling of pharmaceutical products. 
     2. Discussion of the Prior Art 
     A variety of so-called leaflet labels or booklet labels are known in the art and a typical label construction is disclosed in U.S. Pat. No. 5,399,403 in the name of David J. Instance. It is well known for the folded Leaflet or booklet to be overlaminated with a self-adhesive transparent plastics layer. The overlaminate provides durability to the label against inadvertent damage or tearing and also improves the aesthetic appearance of the label. Furthermore, the overlaminate can provide a structural part of the label to enable the leaflet or booklet label to be opened from a closed configuration by pulling the overlaminate away from a surface of a product, such as a pharmaceutical container, which is labelled to enable the leaflet or booklet to be read by a user. In some labels, the overlaminate can be re-adhered to the product to return the label to its closed configuration. Typical plastics materials for use as the overlaminate include oriented polypropylene carrying a pressure-sensitive adhesive on its rear surface. 
     U.S. Pat. No. 4,529,229 discloses a self-adhesive label in which an adhesive strip is provided to retain a folded strip in its folded configuration by being adhered to a top label and an underlying panel of the strip. 
     when pharmaceutical products are labelled, it is often necessary for the label to be printed with specific information, such as a lot of batch code and an expiry date. Such printing is generally achieved by providing a generic printed label for a particular pharmaceutical product and then overprinting a series of the labels with the required batch or lot code and expiry date. 
     A technical problem exists in the art in that there is a need to provide on overlaminated leaflet or booklet labels an area which is suitable for being printed with high quality alphanumeric printing devices suitable for printing batch codes, expiry dates and the like. There is also a need in the art for such overlaminated labels, particularly for pharmaceutical products, to be overprinted with bar codes which contain information relating to the overprinted batch codes, expiry dates, etc. and act as a security feature which can be scanned automatically to check that the required overprinting has been effected. The bar code needs to be small in area yet accurately printed in order to be machine readable at high speeds. 
     When information is overprinted onto paper, i.e. when a non-overlaminated leaflet or booklet label is being printed, ink is printed onto the paper surface of the label and then a laser is employed either to vaporise some of the ink so as to leave white lettering surrounded by the ink or to burn the lettering into the surface of the paper. The present inventor has attempted to replicate this laser printing process onto a plastics overlaminate, in particular an oriented polypropylene self-adhesive laminate. However, following laser treatment the appearance of the printing is poor because the laminate tends to have a bubble effect imparted thereto by the laser, which the present inventor believes results from vapours being emitted from the paper surface and thermal distortion of the plastics laminate. In addition, it is believed that the overlaminate absorbs some of the energy from the laser which may require the utilisation of a relatively powerful laser, or a longer burn time, which may in turn exacerbate the bubbling problem. 
     The present inventor has also attempted to overprint onto a plastics overlaminate by using a thermal transfer printer. Such thermal transfer printers use a multi-element print head with a large number of tiny heating elements that can be turned on and off in a desired pattern or configuration under computer control so as to print selected alphanumeric characters. A ribbon is pressed between the print head and the substrate to be printed and when the print head elements are turned on so as to become heated, the elements soften the coating on the surface of the ribbon in contact with the substrate allowing the coating to stick to the substrate as a pattern of dots. The desired alphanumeric symbols to be printed are of course controlled by selectively activating the desired pattern of heating elements. The present inventor has discovered that the plastics overlaminate surface tends not to be receptive to some thermal transfer coatings. 
     There is also a desire to overprint by means of wet printing. In wet printing a liquid vehicle of a wet printing ink dries by absorption into the printed substrate. This is not possible with a plastics overlaminate because the vehicle cannot absorb thereinto, leading to smudging of the printed image. 
     These problems have been solved in the prior art by adhering a self-adhesive overlabel to the upper surface of the overlaminate, which overlabel has an upper surface which can be printed on by at least one of laser printing and thermal transfer printing. Such a construction is disclosed in WO98/07133 in the name of David J Instance Limited. However, this solution necessarily results in increased material costs due to the need to provide extra material for the overlabel and increased production costs due to the need for an extra production step to apply the overlabel to the upper surface of the overlaminate. 
     WO 97/04433, WO98/07131 and WO98/07132 disclose other types of over-laminated leaflet labels 
     It is therefore an object of the present invention to at least partially solve these problems of the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention provides a self-adhesive label carried on a backing of release material, the label comprising; 
     a self-adhesive support piece which is releasably adhered to the backing; 
     a multi-laminar label portion adhered to a first portion of an upper surface of the support piece, a second portion of the upper surface of the support piece adjacent the first portion being left uncovered by the multi-laminar label portion; and 
     a self adhesive over-laminate adhered to an upper surface of the multi-laminar label portion so as substantially to cover the multi-laminar label portion and to a portion of the hacking of release material adjacent to the multi-laminar label portion thereby to retain the multi-laminar label portion in a closed configuration, and wherein the second portion of the upper surface of the support piece is left substantially uncovered by the over-laminate. 
     The ability to efficiently produce labels in large numbers is often an important requirement- It is therefore a further object of the present invention to provide a method for producing a succession of self-adhesive labels according to the present invention by which large numbers of self-adhesive labels according to the present invention can be produced efficiently with a minimum number of production steps. 
     The present invention therefore further provides a method for producing a succession of self-adhesive labels carried on a backing of release material according to the present invention, said method comprising the steps of; 
     at providing an elongate web comprising a self-adhesive support web having a backing of release material; 
     b) die-cutting and removing from the backing of release material a succession of portions of the support web to leave a succession of intermediate parts of the support web longitudinally spaced along the backing of release material; 
     c) adhering a succession of multi-laminar label portions to the succession of intermediate parts of the support web, each multi-laminar label portion being adhered to a first portion of an upper surface of the respective intermediate part of the support web, a second portion of the upper surface of the intermediate part of the support web adjacent to the first portion being left uncovered by the multi-laminar label portion; and 
     d) adhering a succession of portions of a self-adhesive over-laminate to the upper surface of the succession of multi-laminar label portions so that each portion of the over-laminate substantially covers the respective multi-laminar label portion and a respective portion of the backing of release material which is adjacent to the respective multi-laminar label portion thereby to retain the multi-laminar label portion in a closed configuration, the second portion of the upper surface of each intermediate part of the support web being left substantially uncovered by the over-laminate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
     FIG. 1 shows a perspective view of a self-adhesive label according to a first embodiment of the present invention 
     FIG. 2 shows a side view of a self-adhesive label according to a second embodiment of the present invention. 
     FIG. 3 shows an overhead view of a succession of self-adhesive labels according to a third embodiment of the present invention in an intermediate stage of their production according to a method of the present invention. 
     FIG. 4 shows a cross-section of a self-adhesive label shown in FIG. 3 after final die-cutting taken through line A—A— in FIG.  3 . 
     FIG. 5 shows a cross-section of a self-adhesive label shown in FIG. 3 after final die-cutting taken through line B—B in FIG.  3 . 
     FIG. 6 shows a perspective view of a self-adhesive label according to a fourth embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, there is shown a perspective view of a self-adhesive label according to a first embodiment of the present invention. The self-adhesive label, designated generally as  2 , comprises an underlying support piece  4  which is adhered to a web of release backing material  6  by a layer of pressure-sensitive adhesive a on the rear surface thereof. 
     A booklet  10  is adhered to a first portion of the support piece  4  adjacent transverse edge  12  by a layer of permanent adhesive  14 . A plastic transparent over-laminate  16  is adhered to the upper surface  18  of the booklet  10  by its underlying layer of pressure-sensitive adhesive  26 . The left transverse edge  20  of the over-laminate coincides with the spine  22  of the booklet  10 . 
     The portion  28  of the upper surface of the Support piece adjacent the left transverse edge  24  thereof id left uncovered by both the booklet  10  and the over-laminate  16  and is therefore available for being printed on by, for example, laser printing or thermal transfer printing. 
     The over-laminate  16  has a region  30  which is adhered directly to the release backing material  6 . This region  30  of the overlaminate  16  ensures that the booklet  10  is held in its folded configuration by the adhesion of the over-laminate region  30  to the release backing material  6 . 
     In use, the self-adhesive label is adhered to the surface of a product to be labelled, typically a curved container. When it is desired to open the label, a user manually peels the region  30  of the over-laminate  16  which is releaseably adhered to the container surface away from the surface of the container so that the booklet  10  may be opened and read by a user. After use, the label may be returned to its closed configuration by adhering the over-laminate region  30  again by its self-adhesive surface to the container. 
     Referring to FIG. 2, there is shown a side-view of a self-adhesive label according to a second embodiment of the present invention. This self-adhesive label is identical to that shown in FIG. 1 except that a leaflet  110  is employed instead of a booklet. 
     Next, a method of producing a succession of self-adhesive labels according to a third embodiment of the present invention shall be described with reference to FIG.  3  and FIGS. 4 and 5. 
     An elongate web  300  comprising a support web releaseably adhered to a backing of release material  206  by a layer of pressure-sensitive adhesive  208  on the underlying surface thereof. A longitudinal section of the elongate web  300  is shown in FIG.  3 . In a first step, the support web is die-cut without cutting through the backing of release material. A succession of transverse columns of rectangular shapes  302  is cut into the support web, and the portions of the support web defined by these shapes are removed from the backing simultaneously with die-cutting to leave a succession of three-up columns of rectangular windows  304  in the support web through which the backing of release material  206  is exposed. As will be evident to the skilled person, the portions of support web defined by the rectangular shapes  302  could also be removed in a separate step after die-cutting. 
     It will also be apparent to the skilled person that the rectangular windows  304  do not have to be arranged in transverse columns of three as shown in the drawings, but could alternatively be arranged in columns of any other number depending, amongst other things, on the size of the resultant labels. 
     The left edge  306  of each rectangular window  304  formed in the support web defines the right transverse edge of an intermediate part ( 350 ) of the support web, and the right edge  308  of each rectangular window  304  defines the left transverse edge  224  of an adjacent intermediate part ( 350 ) of the support web. Each column of rectangular windows  304  therefore defines the right transverse edge of a transverse column of three intermediate parts ( 350 ) of the support web, and the left transverse edge of an adjacent transverse column of three intermediate parts ( 350 ) of the support web. 
     The term “intermediate part” refers to the portion of the support web which will form the support piece ( 204 ) in the respective final label. At this stage of production, in this preferred embodiment of the method of the present invention the intermediate parts are connected in the transverse direction by interconnecting portions of the support web, and are only separated from each other in the final die-cutting step which is described below. 
     A gutter  310  of support web is left between each rectangular window  304  in any transverse column. 
     The next step is to apply a succession of booklet strips  312  to the support web, one booklet strip  312  for each transverse column of intermediate parts ( 350 ) of the support web. The outline of the booklet strips  312  is shown by the short-dash line in FIG.  3 . Since the intermediate parts ( 350 ) are arranged in transverse columns of three, each booklet strip  312  also comprises a continuous strip of three booklets  210 , one for each intermediate part ( 350 ) in a single column. Each booklet strip is arranged on the support web such that each individual booklet  210  in the booklet strip  3312  lines up with the respective intermediate part ( 350 ) in the respective transverse column, and such that the right edge  314  of the upper sheet of the booklet strip  312  extends partially over the rectangular windows  304  created in the support web. Each booklet strip  312  is applied to the support web by a layer of permanent adhesive  214 . The booklet strips  312  are of such width that they do not occupy the whole area of the upper surface of the intermediate parts ( 350 ) in the respective transverse column but leave a left-hand portion  228  of the upper surface of each intermediate part  350  in the respective transverse column uncovered. 
     The upper sheet of each booklet composing the booklet strip is provided with a tab portion  340  protruding from its right edge  316  and extending over the respective rectangular window  304  formed in the support web Par of this tab portion  340  remains as a tab  240  in the finished label and facilitates the opening of each booklet  210  in the finished label. 
     Although not a feature of the embodiment shown in the Figures, the booklet strip can be folded in half widthwise before applying it to the support web by doing so, the area occupied by each booklet on the respective support piece in the final label can be reduced by half, whereby a support piece of reduced area can be employed, or the area of the support piece available for subsequent printing can be increased for a support piece of given area. 
     The next step is to apply a succession of transverse strips  318  of self-adhesive transparent plastics over-laminate, one for each booklet strip  312 . A transverse strip  318  of specified width is applied over the full length of each booklet strip  312  and adhered to the upper surface of the respective booklet strip  312  by its underlying layer of pressure-sensitive adhesive  226 . The outline of the over-laminate strips  318  are shown by the long-dash lines in FIG.  3 . Each over-laminate strip  318  is arranged on the respective booklet strip such that its right transverse edge  320  finishes approximately level with the right edge  322  of the tab portions  340  protruding from the upper sheet of the respective booklet strip  312 . The width of the overlaminate strip  318  is such that its left edge  324  lies slightly to the right of the spine  326  of the booklet strip  312 . 
     The final step is to die-cut along the U-shaped line shown by the crossed-line in FIG.  3 . The final cut die thus cuts through the booklet strip  312  and overlaminate strip  318 , as well as through the support web to define the top and bottom longitudinal edges of each label, and cuts though the booklet strip  312  and overlaminate strip  318  to define the right transverse edge of each label. 
     The corners of the U-shaped die are rounded whereby the top-right right and bottom-right corners of each resultant label are also rounded. 
     The right-hand edge  308  of each rectangular window  304  that was originally cut out of the support web becomes the left edge  224  of the respective finished label. There is therefore no support web between the left and right transverse edges of longitudinally adjacent labels that has to be taken up with the unwanted matrix of support web. 
     The longitudinally-extending gutters  310  of support web left deliberately between the rectangular windows  304  la the pre-die-cutting step have the result that the matrix of waste support web to be removed from the backing of release material is continuous in the longitudinal direction and can therefore be removed easily from the backing of release material. This removal of the waste matrix is further facilitated by the reinforcing effect of the over-laminate on these sections of the support web. 
     The portion  228  of the upper surface of each label to the left of the spine  222  of its booklet  2310  remains uncovered by the overlaminate  216  t is therefore available for laser coding or another alternative method of printing such as thermal transfer printing without the need to apply an overlabel. 
     The resultant self-adhesive label after final die-cutting is shown in FIGS. 4 and 5 as cross-sections taken through line A—A— and line B—B of FIG. 3, respectively. 
     In use, the self-adhesive label is adhered to the surface of a product to be labelled, typically a curved container When it is desired to open the label, a user manually grabs the tab  240  which is not adhered to the container surface directly and the tab  240  is pulled away from the container thereby to pull the over-laminate region away from adhesive contact with the surface of the container so that the booklet  210  may be opened and read by a user. After use, the label may be returned to its closed configuration by adhering the over-laminate region  230  again by its self-adhesive surface to the container. 
     Referring to FIG. 6, there is shown a perspective view of a self-adhesive label according to a fourth embodiment of the present invention. This self-adhesive label is similar to that shown in FIG.  1 . However, in this embodiment, the booklet  410  is arranged on the first portion of the upper surface of the support piece  404  adjacent transverse edge  412  in art unfolded configuration (the spine of the booklet is shown by the dashed line  440 ) and is only temporarily held on the first portion of the upper surf ace of the support piece  404  by a layer of a removable adhesive  414 . The plastic transparent overlaminate  416  is adhered to the upper surface  418  of the unfolded booklet  4310 , and extends beyond the left transverse edge of the unfolded booklet  410  such that a region of the overlaminate  416  is adhered to a part of the second portion  428  of the support piece  404  uncovered by the booklet  410  whilst still leaving a substantial part of the second portion  428  of the support piece  404  uncovered by both the booklet  410  and overlaminate  416 , and therefore available for subsequent printing. The overlaminate  4316  is adhered to the second portion  428  of the support piece to an extent sufficient to securely hold the booklet  410 /overlaminate  416  assembly on the support piece  404 . 
     In use, the self-adhesive label is adhered to the surface of a product to be labelled, usually a curved container. When it is desired to open the label, a user manually peels the region  430  of the overlaminate  416  which is releasably adhered to the container surface away from the surface of the container, and also lifts the unfolded booklet  410  from the first portion of the upper surface of the support piece  404  so that the pages of the booklet  4101  can be turned and read. After use, the label is returned to its closed configuration by adhering the overlaminate region  430  again by its self-adhesive surface to the container. 
     In this embodiment, the booklet  4101  is only permanently attached to the support piece  404  via the overlaminate  416 . The adhesion of the overlaminate to the second portion  428  of the support piece  404  therefore prevents the left edge of the booklet from falling open when the label is closed and prevents the booklet from becoming completely detached from the label when the label is opened. 
     As will be clear to the skilled person, the layer of removable adhesive  4314  shown in FIG. 6 only serves to temporarily hold the unfolded booklet  410  in place on the support piece  404  until the overlaminate  4116  is applied in view of this function of the layer of removable adhesive  414 , it will also be clear to the skilled person that it is equally possible to alternatively use only a couple of dots of removable adhesive to temporarily adhere the unfolded booklet  410  to the first portion of the upper surface of the support piece  404 , or to provide the temporary adhesion by means of electrostatic charge or some similar transitory mechanism rather than by using a removable adhesive In fact, this will be advantageous since the booklet  410  will be more readily liftable from the first portion of the support piece when the label is opened to read the booklet. 
     A succession of the above-described self-adhesive labels according to the fourth embodiment can be produced by the method described earlier with appropriate modifications thereto in accordance with the modifications in construction.