GB2306938A

GB2306938A - Watermarked labels

Info

Publication number: GB2306938A
Application number: GB9523015A
Authority: GB
Inventors: Richard Bryan Jotcham; Gerald Sidney Payne; Keith Noel Brown
Original assignee: Portals Bathford Ltd
Current assignee: Portals Bathford Ltd
Priority date: 1995-11-09
Filing date: 1995-11-09
Publication date: 1997-05-14
Anticipated expiration: 2015-11-09
Also published as: HK1010762A1; DE69603144D1; DE69603144T2; EP0773527A1; EP0773527B1; GB9523015D0; GB2306938B; DK0773527T3; ES2135176T3

Description

2306938 WATERMARKED LABELS The invention relates to watermarked labels and

in particular to a label which can be used for security applications, such as an authentication certificate, means of identification or the like as proof of the authenticity or origin of an article to which it is adhered.

Documents of value and means of identification, such as banknotes, passports, identification cards, certificates and the like, are vulnerable to copying or counterfeiting. The increasing popularity of colour photocopiers, electronic scanning and other imaging systems, and the improving technical quality of colour photocopiers, has led to an increase in the counterfeiting of such documentation. There is, therefore, a need to improve the security features of such documentation, or paper, to add additional security features or to enhance the perceptions and resistance of simulation to existing features. Steps have already been taken to introduce optically variable features into such documentation which cannot be reproduced by a photocopier or an electronic scanner. There is thus a demand to introduce features which are discernible by the naked eye but "invisible" to, or viewed differently by, a photocopier or scanner. Since the photocopying process typically involves reflecting high energy light on an original document containing the image to be copied, one solution is to incorporate one or more features into the document which have a different perception in reflected and transmitted light. Such examples of such security features include watermarks, embedded security threads, fluorescent pigments and the like.

Unfortunately, for documents containing these security features the ability to inspect the documents in both reflected and transmitted light is necessary to identify the differences. These types of features have therefore not been considered to be suitable for applications where only one side of the document can be viewed in reflected light, e.g. on a label stuck to another article.

It is therefore an object of the present invention to provide a label containing one or more security features which can be applied to an article so that the security feature can be identified before application and in situ from one side of the document alone.

According to the invention there is provided a label comprising a base layer having an adhesive applied to one side of the base layer, the base layer incorporating at least one watermark feature, said watermark features having a plurality of first and second areas which appear lighter and darker respectively than the base layer when the label is viewed in transmitted light, the perceived appearance of said first and second areas changes when the label is applied, in use, to an opaque background of a darker shade or colour than the base paper so that the first and second areas appear darker and lighter respectively.

Contrary to all technical prejudices, it has been found that when a label is made from paper containing a watermark and applied to a background of a darker or different colour to that of the base paper there is an unexpected and surprising effect in that the watermark is visible in a modified form in reflected light. Such watermarks can also be detected by touch as there is a surprising increase in the received variations in the surface of the label in the area of the watermark, - 3 thus providing an additional security check. Thus a label according to the present invention has wideranging security applications as it can be checked for authenticity before application by viewing in both transmitted and reflected light, and then in situ by viewing in reflected light only and by touch. Labels containing such watermark features provide a high degree of security because they cannot be photocopied even if the label is removed from the article to which it is attached.

Preferably the label further includes a backing sheet to protect the adhesive. The backing sheet may be clear, translucent or light impermeable.

The adhesive may be clear or translucent or is coloured and of a different colour to the colour of the base layer.

The label preferably further includes a security thread embedded partially or wholly within the base layer and/or one or more surface security features.

The base layer is preferably of paper.

In a preferred embodiment of the invention the base layer is a two-ply structure formed from two substrates, a first substrate containing the watermark feature.

The first substrate is preferably of paper. The second substrate is preferably coloured. The second substrate may be of a material other than paper.

Preferably the thickness of the paper fibres at different locations within the watermark feature is up to 20% less than that of the base layer in the thinner part and up to 20% greater than that of the base layer in the thicker part.

The density of the paper fibres at different locations within the watermark feature is preferably up to 20% greater than the density of the base layer in the denser areas and up to 20% less in the density of the base layer in the less dense areas.

The constituents of the base layer may be natural, synthetic or a combination of natural and synthetic.

The watermark feature preferably provides a tactile effect when the label is applied, in use, to a background.

A preferred embodiment of the present invention will now be described in detail, by way of example only, with reference to the accompanying drawing, Fig. 1, which is a schematic representation of a label according to the present invention.

A label 10 is formed from a base paper 11. The paper 11 contains one or more watermark features 12, 13. Two such features are illustrated in Fig. 1, one being a pictorial image 12 and the other watermark bars 13. The label 10 has an adhesive area on one surface, hereinafter referred to as the back of the label 10.

The watermarked paper 11 may be made using known papermaking machines such as a cylinder mould or Fourdrinier machine or it may even be hand- made. A range of fibre types can be used in the making of such paper including synthetic or natural fibres or a mixture of both. The actual preparation of the fibre is unrestricted depending on what effect it is wished to produce in the finished paper. This is contrary to the accepted procedures for making security paper for documents such as banknotes, passports, identification cards and so on which needs to be hardwearing, resilient and self-supporting.

A watermark is created by varying the density of paper fibres so that in some areas the fibres are denser and others less dense than that of the base paper. When viewed in transmitted light the less dense areas are lighter and the denser areas darker than the base paper, and the contrasts can be seen very clearly.

The actual grammage of the paper within the watermark 12, 13 thus has a significant effect on the clarity of the watermark 12, 13 especially when included in a label 10 applied to a background. Whilst the varying density of the paper fibres affects the visibility of the watermark 12, 13, in both reflected and transmitted light the varying thickness of the paper has an effect on the tactility of the watermark 12, 13 whereby raised or thicker areas can be felt where the fibres are denser. The density of fibres can be varied by varying the relative depth in the watermarking dies so that the relative quantity of fibres deposited in different areas of the watermark differ dramatically. The density of the paper can also be affected by adding other components to the papermaking furnish, such as fillers which change the opacity of the paper. Thus areas with more fibres made from a furnish including fillers will appear much more opaque than those areas with fewer fibres or indeed paper without such fillers. Colouring the base paper 11 also affects the visibility of the watermark and the depth of clarity between the thick and thin areas

It is envisaged that the thickness of the base paper 11 for making a label 10 according to the present invention will be in the range of 70 to 150 microns and preferably 115 microns. The thicknesses of the paper within the watermark could vary by plus or minus 20% of the base thickness, i.e. up to 20% thinner within the lighter areas and up to 20% thicker in the darker areas. This range of variation is usually avoided in watermarks in security paper as the paper is weakened by such variation and processes such as calendaring or in intaglio printing can damage the paper or the watermark image causing pin holing or crushing. Paper having watermarks with such a varying range of thicknesses could not be used for banknotes or other similar security documentation which must be hardwearing and resilient due to zheir continuous handling. For a label, however, this is not a disadvantage as the label 10 is supported by its backing, before application, or by the article to which it is adhered, after application. Furthermore, in an attempted removal of such a label 10, this weakness in the paper 11 is likely to lead to tearing, thus providing a tamper-proof feature.

In one specific example of the present invention, the preferred grammage of the base paper 11 is 90gsm. The denser areas of the watermark feature 12, 13 are 20% more dense than that of the base paper 11 and the lighter areas 20% less dense than the base. However, the grammage of the base paper 11 may vary from 55 to 120gsm.

The use of pictorial images as watermarks is fairly common in many security documents. The other type of watermark feature shown in Fig. 1, the watermark bars 13, are created when paper is made with a security thread 14 embedded within the paper. Such paper can be made by a method such as that described in patent EP 0059056, where the security thread is exposed at regular intervals in windows in the surface of the paper. In the areas 13 between the windows, the fibres are denser than in the base paper 11. These can be made to appear as regular or irregular bars as preferred. These are known as watermark bars 13 and when the label 10 is applied, reflect the original colour of the label 10, whereas the base paper 11 takes up the colour of the background.

The adhesive on the back of the label 10 can be any suitable adhesive applied in a variety of forms, including a water activated gum, a selfadhesive coating with a protective silicone backing, a doublesided tape or sheet. The adhesive itself may be ultra violet curable, pressure sensitive, permanent or a repositionable adhesive. The adhesive composition dictates the thickness of the adhesive.

In one embodiment of the invention, the label has a backing paper which is used to protect the label before it is applied to the article. A clear or highly translucent backing may be used, then this enables the watermark 12, 13 and any other security feature to be checked in transmitted as well as reflected light before the backing is removed and before application of the label. However, a nontranslucent backing may also be used, which requires the removal of the backing before the label 10 can be checked before application.

When the label 10 is applied to an article which provides a darker background to that of the base paper 11, there is a significant change in the appearance of the watermark feature 12, 13. The areas which appear, in transmitted light, very light become dark and the darker areas appear whiter. Thus a negative watermark changes to a positive image and a positive watermark changes to a negative image. When the label 10 is applied to an article, the base paper 11 tends to take up the colour of the background to a certain degree. The less dense areas of the watermark 12, 13 take it up to a greater degree and the dense areas much less. Thus contrary to expectation the watermark image is clear. The darker the background to which the label - 8 is applied, the clearer the watermark feature 12, 13 is. Thus the label 10 according to the present invention provides a two-fold test for its authentication before it is applied to an article, as well as providing security features which can be checked once. These include the visible watermark image when examined in reflected light and the tactile effect resulting from the varying thicknesses of the paper within the watermark. This tactile effect is more significant when the surface of the adhered label 10 is felt than when both sides of paper containing a watermark can be felt.

When a label 10 is applied to a coloured surface, the change to the watermark image is more significant in that the thinner areas of paper allow more colour to show through whereas the thicker areas of paper remain the colour of the base paper. The intensity of the colour of the background enhances the intensity of the effect. A range of random colours beneath the watermark feature 12, 13 can cause a range of pastel colours to be transmitted which is particularly difficult to counterfeit.

It should be noted that if a label 10 to a background which is the same colour as paper 11, then the watermark feature 12, 13 invisible and cannot be viewed in reflected However, the tactile effect still remains. applications where the article to which the is to be applied may be of a similar colour base paper 11, the adhesive may be coloured violet fluorescent. Alternatively adhesive may be used to allow the removed and checked in transmitted embodiment of the invention may be applications, such as certificates is applied the base becomes light. Thus, for label 10 to the or ultra a re-positionable label 10 to be light. This unsuitable for some of authenticity, - 9 but may have other applications.

Different types of watermark features 12, 13 have different advantages. A pictorial image 12 can be very detailed and complex which significantly reduces the risk of counterfeiting. However the watermark bars 13 provide a more startling visible effect and can be verified at a greater distance than the more subtle pictorial image 12. The watermark bars 12, 13 also provide a greater tactile effect than the pictorial image 12. It is thus envisaged that, although the label may have just one watermark feature, a combination of different watermark features may be used to provide enhanced security.

The base paper 11 of the label 10 may be single or two-ply paper. Two-ply paper is generally made using two separate vats of papermaking furnish which produce two substrates which are compressed together to form a finished paper. In another embodiment of the present invention, twin-ply paper can be used, where one substrate is made from a non-coloured furnish, and this is the substrate which contains the watermark feature and the second substrate is made from a coloured furnish. A label 10 made from such two colour paper is particularly suitable for applications where the background colour of the article to which the label 10 is applied is likely to be the same as the uncoloured part of the base paper. This ensures that the watermark is visible once the label 10 has been applied to the article.

A two-ply label can also be made according to the present invention in which the substrate which does not include the watermark is not made from paper but could be a clear or a coloured film.

The present invention is also highly compatible with many other security features to enhance the - r, security of the label 10. For example, a wide range of different types of security thread can be used, including holographic threads, demetallised threads, demetallised holographic threads, fluorescent threads, thermochromic threads, coloured/metallised threads, machine-readable threads, optically variable threads and microprinted threads. It is significant to note that in labels 10 containing demetallised threads, the demetallised areas can be seen much more clearly when the label 10 is applied to a darker background. The demetallised (negative) areas become positive where the colour of the background comes through.

other surface features may also be included such as planchette bands, fibre bands, iridescent coatings and transparentising coatings and print.

Labels 10 according to the present invention are also compatible within any known forms of printing such as intaglio, flexo-gravure, ink jet, hot foil stamping and so on. The labels 10 may also have a glossy or other finish which is clear or translucent.

Such labels 10 may have a wide range of uses especially as certificates of origin or authentication, and in particularl in fields where counterfeiting of the products to which the labels 10 are attached is or may be be rife, such as high value added or fast moving consumer goods.

11 -

Claims

CLAIMS:

1. A label comprising a base layer having an adhesive applied to one side of the base layer, the base layer incorporating at least one watermark feature, said watermark features having a plurality of first and second areas which appear lighter and darker respectively than the base layer when the label is viewed in transmitted light, the perceived appearance of said first and second areas changes when the label is applied, in use, to an opaque background of a darker shade or colour than the base paper so that the first and second areas appear darker and lighter respectively.

2. A label as claimed in claim 1 in which the label further includes a backing sheet to protect the adhesive.

3. A label as claimed in claim 2 in which the backing sheet is clear or translucent.

4. A label as claimed in claim 2 in which the backing sheet is not lightpermeable.

5. A label as claimed in any one of the preceding claims in which the adhesive is coloured and of a different colour to the colour of the base layer.

6. A label as claimed in any one of the preceding claims further comprising a security thread embedded partially or wholly within the base layer.

7. A label as claimed in any one of the preceding claims further comprising one or more surface security 12 features.

8. A label as claimed in any one of the preceding claims in which the base layer is of paper.

9. A label as claimed in any one of the preceding claims in which the base layer is a two-ply structure formed from two substrates, a first substrate containing the watermark feature.

10. A label as claimed in claim 9, in which the first substrate is of paper.

11. A label as claimed in claim 9 or claim 10 in which the second substrate is coloured.

12. A label as claimed in any one of claims 9, 10 or 11 in which the second substrate is not of paper.

13. A label as claimed in any one of the preceding claims in which the thickness of the paper fibres at different locations within the watermark feature is up to 20% less than that of the base layer in the thinner parts and up to 20% greater than that of the base layer in the thicker parts.

14. A label as claimed in any one of the preceding claims in which the density of the paper fibres at different locations within the watermark feature is up to 20% greater than the density of the base layer in the denser areas and up to 20% less than the density of the base layer in the less dense areas.

15. A label as claimed in any one of the preceding claims in which the constituents of the base layer are - 13 natural, synthetic or a combination of natural and synthetic.

16. A label as claimed in any one of the preceding claims in which the watermark feature provides a tactile effect when the label is applied in use, to a background.

17. A label substantially as hereinbefore described with reference to and as shown in the accompanying drawing.