Self-adhesive labels are used very widely, throughout many branches of industry. Such labels are manufactured from a label stock comprising a web of backing material and a web of label material, laminated together. The backing material has a silicone or similar release coating on one face and the label material has a contact adhesive on the face which will not be exposed, when in use, the contact adhesive of the label material being pressed against the silicone release coating of the backing material so that the labels may be stripped away from the backing material. Such label stock is converted to form labels typically by printing and die-cutting steps, followed by the stripping away of the waste label material, so as to leave a succession of individual labels adhering to the backing material, along the length thereof.

Though in general the backing material carries on one face a coating of a silicone compound to give that material the required release characteristics, the backing material may have a release coating of some other compound besides a simple silicone coating. However, for convenience all such coatings will be referred to in this specification as a "release coating"though it is to be understood that this term is not to be regarded as limited solely to a silicone coating; rather it extends to compounds of other materials having similar release characteristics.

Converted labels are usually supplied to a user either in reeled form or in concertina-folded form. The converted labels are applied to products in a labelling machine, which usually reels the unwanted backing material following the stripping of the labels from that material. The backing material is then discarded, as waste.

The backing material frequently is of a high quality paper, firstly so as to have sufficient strength to support the labels through the conversion and labelling processes and secondly to be able to carry the silicone release coating without that coating becoming detached at the time of stripping the labels. Despite this, following the stripping of the labels, the waste backing material is usually disposed of by incineration, though sometimes it is used as a fuel, for example by being burnt in a furnace or boiler. It has also been proposed to slit and then crush the waste backing material, so as to permit its use as a shredded packing material.

The present invention concerns an alternative method of utilising the waste backing material from a self-adhesive labelling process, so as to give rise to a useful end product having an enhanced value. Thus, the invention aims at converting a waste product, which at present usually is disposed of at a total loss, to a product which can be sold, at a profit.

According to the present invention, there is provided a method utilising a web of waste self-adhesive label backing material having a release coating on one face, following the stripping of the labels from said one face, comprising applying a contact adhesive to the other face of the backing material and then reeling the backing material to form a roll of useful self-adhesive tape.

The present invention stems from a realisation that the waste backing material readily lends itself to the manufacture of self-adhesive tape, having regard to the presence of the silicone release coating on one face of the material. Thus, on reeling web, following the application of a contact adhesive to the other face, the adhesive only lightly adheres to the silicone release coating and may readily be released therefrom to permit the application of the tape to some other product, without the adhesive losing its adherent (or tacky) properties.

The backing material used in the method of this invention may comprise a web of a paper material or a web of a plastics material.

Generally, a web of paper material is more suitable for the method, since such materials may be more receptive to the self-adhesive coating to be applied to the face of the web not carrying the silicone release coating.

The backing material advantageously is reeled at the time of stripping the self-adhesive labels therefrom, in a labelling machine.

Thereafter, the reeled waste backing material may be stored until required for conversion to self-adhesive tape. Alternatively, a labelling machine may be modified so as to include an adhesive applicator arranged to apply a suitable adhesive to said other face of the waste backing material as that material is led away from the labelling station of the machine, the backing material then being directly reeled as self-adhesive tape, ready for subsequent use.

The adhesive may be applied to the backing material using a known form of adhesive applicator. For example, the adhesive could be applied by a transfer printing step, or by an applicator head of a known form, or by a spray head.

Depending upon the width of the waste backing material, and the intended use for the self-adhesive tape manufactured therefrom, the manufacturing step may include a slitting step, to reduce the overall width of the tape. Typically, the long edge regions of the waste backing material may be removed and at the same time the material is slit along its length so as to yield two (or even more) reels of tape, either of the same width or different widths.

Selection of an appropriate adhesive should take into account the intended use of the end product, as well as the material of the waste backing, to ensure good adhesion of that adhesive to the backing material. For example, the adhesive may comprise a solvent-based or water-based non-drying high-tack adhesive. Such an adhesive may be selected from the class of adhesives known as emulsion adhesives.

Another possibility would be to use heat or UV sensitive adhesives, to

obtain particular properties for certain applications. Suitable adhesives for use in the manufacture of self-adhesive tape will be known to those skilled in the art.

This invention extends to a roll of self-adhesive tape whenever made from a web of waste label backing material, by a method of this invention.

By way of illustration only, an example of apparatus arranged to perform a method of the present invention will now be described in detail, reference being made to the accompanying drawing which diagrammatically illustrates the processing steps.

The starting material for the performance of this example of the invention is a web of paper-based or plastic-based waste label stock backing material carrying a silicone release coating on one face, the web having been reeled immediately after the stripping of the converted labels from the backing material, in a labelling machine. The reel 10 of waste backing material is loaded into the apparatus shown in the drawings by mounting the reel on a rotatable carrier 11. The web 12 drawn from the reel 10 is guided by various rollers 13, only one of which is shown in the drawings, to an adhesive applicator 14 arranged to apply an adhesive coating 15 to the other face of the web-that is, the face of the web not having the silicone release coating. In order to avoid problems associated with the application of adhesive to the very edges of the material, it is preferred to leave non-adhesive edge bands 16 along the length of the web.

Though various non-drying water-based or solvent-based adhesives could be employed, a typical example of a suitable adhesive is an emulsion acrylic.

The web is then directed to conventional slitters 17, arranged to remove the edge bands 16 and also to slit in half (or other proportions) the web, so as to produce two separate tape-like strips. These are guided

by further rollers 18 to a reeling station 19, where the strips are reeled, ready for subsequent use. During this reeling step, the adhesive coating on the material is pressed against the silicone release coating on the waste material, so that the tape may readily be unreeled, when it is required for use. As can be seen in the drawing, the reel is finished with the silicone release face directed outwardly so that no adhesive is exposed on completing the reel of tape.

A typical use for self-adhesive tape manufactured from waste backing material in accordance with the present invention is a tape intended for packaging, sealing parcels and so on. Thus, such tape typically will be used industrially, rather than sold through retail outlets to the domestic market. Since the tape is produced from waste label- backing material, the invention offers an improved quality of tape for automatic case-sealing, since the properties of such backing material are superior to those of currently-available commercial case-sealing tapes. In particular, the release quality of the backing material is better than that which can be expected with conventional sealing tapes.