GB2597360A

GB2597360A - A security sheet

Info

Publication number: GB2597360A
Application number: GB2107465.3A
Authority: GB
Inventors: Dhillon Baljeet; Sugdon Matthew
Original assignee: De la Rue International Ltd
Current assignee: De la Rue International Ltd
Priority date: 2018-03-02
Filing date: 2018-03-02
Publication date: 2022-01-26
Anticipated expiration: 2038-03-02
Also published as: GB2597360B; GB202107465D0

Abstract

A security sheet (11, Fig.1) comprises a data sheet (15, Fig.1) for displaying data and an attachment layer 17. The attachment layer comprises a plurality of tabs 25 extending from an attachment portion 26 for attaching the data sheet into a security document (10, Fig.1). The plurality of tabs are attached to the data sheet such that the attachment layer is attached to and extends from the data sheet. The data sheet is formed from at least a plurality of body layers 18 and at least one tab of the plurality of tabs is attached between two adjacent body layers attached to one another. The attachment layer can comprise a textile wherein the attachment portion comprises a plurality of warps (30, Fig.3) intersecting a plurality of wefts (31, Fig.3) and the plurality of tabs comprises portions of the plurality of warps extending from the plurality of wefts. There is also disclosed a method of forming the security sheet.

Description

A SECURITY SHEET

The present invention is directed towards a security sheet for displaying data. The present invention is further directed towards a security document comprising such a security sheet and a method of manufacture such security sheets and documents.

Security documents and booklets, such as passports, passbooks, identification documents, certificates, licences, cheque books and the like, commonly comprise one or more security sheets on which information is provided. A passport booklet typically comprises a cover, a plurality of internal visa pages and at least one security sheet displaying the personal data of the passport holder. Typically the visa pages are made from paper and are sewn together along a stitch line coincident with the fold line of the document. The security sheet may be formed from a plastic, typically polycarbonate, and during its manufacture a number of thin plastic layers are laid over one another and laminated together, thereby forming a thicker plastic body. As this plastic body is typically rigid and unable to bend without plastic deformation it is generally not attached at the stitch line such that it can still bend at the fold line.

The plastic body may therefore be attached about the fold line using a flexible layer attached to and extending from the plastic body. Usually steps are taken to ensure that the plastic body is resistant to delamination by counterfeiters or forgers attempting to adapt the personal data. Furthermore, the attachments of the flexible layer to the plastic body and about the fold line need to be sufficiently durable and resistant to delamination to endure for the lifetime of the security booklet, which is often 10 years or more in the case of passports.

EP-B1-1592565 proposes a two zone data sheet. In the first zone a flexible and bending resistant attachment portion protrudes as a strip into a data portion. In the second zone a uniform data region contains the personal data and improves resistance to delamination by being substantially homogenous or uniform. However, the strip of the attachment portion is small and forms distinct boundaries within the data portion and at the edge of the data portion where the attachment portion enters the data portion. As a result, the first zone is less resistant to delamination and presents a clear boundary at the data portion edge for a counterfeiter to insert a sharp implement for an attempted delamination. In effect, a more delamination-resistant uniform data region is achieved at the expense of a less delamination-resistant attachment between the flexible layer and data portion.

EP-B2-1502765 discloses a data page having a flexible textile layer attached to a data carrier by forming welding points of the data carrier through mesh openings of the textile during lamination. The use of a textile improves the durability of the connection between the flexible layer and the stitch line. However, the welding points form a very small area of attachment between the adjacent layers and the rest of the textile forms a distinct boundary. Therefore, the data page is less resistant to delamination.

Objects of the present invention include to addressing these problems. Objects of the present invention include providing an improved security sheet with increased resistance to delamination by a forger and improved durability. A further object is to provide a strong and durable attachment between the security sheet and the rest of a security document. Further objects include providing an improved method of manufacture such a security sheet and a security document comprising such a security sheet.

The present invention provides a security sheet in accordance with claim 1 and a method in accordance with claim 13.

The present invention therefore provides a security sheet comprising: a data sheet for displaying data; and an attachment layer comprising a plurality of tabs extending from an attachment portion for attaching the data sheet into a security document, wherein the plurality of tabs are attached to the data sheet such that the attachment layer is attached to and extends from the data sheet.

Surprisingly it has been found that the tabs provide a very strong and durable connection between the attachment and data sheets. Rather than having welding points through mesh openings to lock the attachment layer to the data sheet as in EP-B21502765, the increased surface area of contact between the plurality of tabs and data sheet can provide a strong frictional force against attempted removal of the attachment layer from the data sheet.

Preferably the plurality of tabs are attached to the data sheet by being at least partially embedded in the data sheet. As the material of the data sheet is integrated with the tabs, the security sheet can substantially resist delamination even in the region where the attachment layer overlaps the data sheet and, for example, around the personal data.

This is particularly contrary to the teaching of EP-B1-1592565, which requires the uniform data region in order to avoid delamination.

Preferably at least one spacing separates at least two adjacent tabs of the plurality of tabs. Material of the data sheet preferably at least partially fills the at least one spacing such that the at least two adjacent tabs are at least partially embedded in the data sheet.

Thus it is very difficult to remove the plurality of tabs from the data sheet without causing substantial and identifiable damage to the material of the data sheet.

The security sheet preferably comprise data elements located in or on the data sheet. The plurality of tabs may at least partially overlap the data elements. The data elements may comprise laser markings and/or printed ink and preferably comprise personal data relating to a holder of the security sheet. A counterfeiter or forger will therefore struggle to remove the plurality of tabs without affecting at least some of the data and struggle to alter the data without affecting the plurality of tabs. A counterfeit or forged document is therefore also more easily identified.

Preferably the attachment layer comprises a textile. Preferably the attachment portion comprises a plurality of warps intersecting a plurality of wefts and the plurality of tabs comprises portions of the plurality of warps extending from the plurality of wefts or portions of the plurality of wefts extending from the plurality of warps. As a result, the attachment portion is sufficiently flexible, resistant to plastic deformation and durable.

However, as there is no mesh of the textile in the data sheet (as taught by EP-B2-1502765) the boundary between the warps is smaller and therefore more resistant to delamination.

Preferably the attachment layer comprise at least one film layer. Preferably the attachment portion comprises an elongate body of the at least one film layer and/or the plurality of tabs comprise the at least one film layer and extend from the elongate body. The at least one film layer can be easily integrated into the data sheet during lamination and can have a suitable shape for further improving the connection between the data sheet and attachment portion.

The present invention also provides a security document according to clause 14, a laminar structure according to clause 15, a method according to clause 16 and an attachment layer according to clause 21. 4 -

By way of example only, embodiments of a security sheet, a security document and a method of manufacture in accordance with the present invention are now described with reference to, and as shown in, the accompanying drawings, in which: Figure 1 is a perspective view of a security document, particularly a passport, according to the present invention in an open configuration; Figure 2 is a schematic cross-sectional side elevation of an fold line area of the security document of Figure 1 in an exploded configuration; Figure 3 is a schematic plan view of an embodiment of a security sheet according to the present invention; Figures 4A, 5A, 6A and 7A are each cross-sectional side elevations of embodiments of a laminar structure according to the present invention; Figures 4B, 5B, 6B and 7B are each cross-sectional side elevations of embodiments of a security sheet formed form the laminar structures of Figures 4A, 5A, 6A and 7A respectively; Figure 8 is a schematic plan view of a further embodiment of a security sheet according to the present invention; Figure 9 is a cross-sectional side elevation of parts of particular embodiments of the security sheets of Figures 3 and 8 through section A-A; Figures 10 to 12 are each schematic plan views of further embodiments of a security sheet according to the present invention; Figure 13A is a schematic plan view of a laminar structure for forming a plurality of security sheets according to the present invention; Figure 13B is a schematic plan view of a security sheet formed from the laminar structure of Figure 13A; and Figures 14 and 15 are each schematic plan views of further embodiments of a security sheet according to the present invention.

Figures 1 and 2 illustrate a security document 10 in accordance with the present invention. The security document 10 may be of any suitable type, but preferably comprises a security booklet, such as a passport as illustrated, a passbook, an identification document, a certificate, a licence, a cheque book or the like. The security document 10 comprises a security sheet 11, in this case a data page, foldable about and preferably attached along a fold line 12 to a plurality of leaves 13, which preferably comprise a fibrous substrate, comprising for example paper and/or cotton, and may form visa pages. The security document 10 also comprises a cover 14, which may also be foldable about and attached to the fold line 12 and/or may be adhered to an outer leaf (not shown) located on

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the outside of the leaves 13 and security sheet 11. The attachment is preferably by means of stitching through the security sheet 11, leaves 13 and/or cover 14 at the fold line 12, although other attachment means such as adhesion may be used. The attachment line may be offset from the fold line 12.

The security sheet 11 comprises a data sheet 15, which preferably comprises plastic, for displaying data 16 and an attachment layer 17 attached to the data sheet 15. The data sheet 15 extends across a width from an inner edge 22, located proximate the fold line 12, to an outer edge 23, distal to the fold line 12 and at the edge of the security document 10. The security sheet 11 is preferably formed by the lamination of a laminar structure 19, embodiments of which are illustrated in Figures 4A, 5A, 6A, 7A and 13A, comprising at least one body layer 18 for forming the data sheet 15 and the attachment layer 17. The data sheet 15 is preferably formed by the lamination together of a plurality of body layers 18. During lamination heat and/or pressure are applied to fuse the plurality of body layers 18 together. The lamination may be performed using any suitable method and may be a substantially in-line method, similar to that of WO-A-2017/060684 and WO-A2017/060688, in which a plurality of security sheets 11 are formed continuously. In addition, the connection of the plurality of body layers 18 may be by adhesion, welding and/or any other suitable method.

The data sheet 15 extends across a thickness between substantially planar first and second outer surfaces 28, 29. Preferably the data sheet 15 is substantially rigid or at least semi-rigid. The data sheet 15 and at least one body layer 18 may comprise at least one of a thermoplastic polymer, polycarbonate, polybutylene terephthalate, polyester, polyethylene, polypropylene, polyvinyl chloride, a co-polymer comprised of any of the previous thermoplastic polymers, a fibrous substrate and the like. Each body layer 18 may be between approximately 50 pm thick and approximately 1000 pm thick. The thickness of the data sheet 15 is preferably at least approximately 150 pm and may be between approximately 300 pm and approximately 1000 pm thick.

The data 16 preferably comprises a plurality of data elements, each forming an alphanumeric character, symbol, logo, indicia or the like. The data 16 preferably comprises personal or variable data 20, which specifically relates to the holder of the security sheet 11, and fixed or non-variable data 21, which is typically the same across a plurality of security documents 10 and security sheets 11. The data 16 may be incorporated into the data sheet 15 before and/or after lamination in any suitable manner, for example by printing 6 -ink or laser marking. At least one body layer 18 may be laser markable, such as by containing suitable additives, so that the data sheet 15 can be laser marked.

In the present invention, and as best illustrated in Figures 3 to 15, the attachment layer 17 comprises a plurality of tabs 25 extending from an attachment portion 26. The attachment portion 26 is located at least partially, preferably entirely, outside of the data sheet 15 and is attached in the security document 10, preferably along the fold line 12 as shown. The attachment portion 26 may comprise a substantially elongate sheet or body as illustrated. Stitching preferably extends through the attachment portion 26 and along the fold line 12 to attach it to the further leaves 13. The attachment portion 26 is preferably flexible and can fold around the fold line 12 such that it does not impair the opening and closing of the security document 10. The attachment portion 26 is preferably substantially resistant to plastic deformation during folding such that it is sufficiently durable to withstand repeated folding over the lifetime of the security document 10 without failure. The attachment portion 26 is preferably substantially tear resistant, particularly at the fold line and around any stitching passing through it. As discussed in further detail below, the attachment portion 26 may therefore comprise a textile, a woven or nonwoven textile, threads, strips, at least one film layer 40 and/or the like. The attachment layer 17 may comprise a plurality of layers bonded or otherwise laminated together.

The tabs 25 are at least partially located in or on and attached to the data sheet 15 such that the attachment layer 17 extends from the data sheet 15 and preferably form the inner edge 22. Each tab 25 comprises a substantially elongate body attached, integrated or otherwise connected to the attachment portion 26. At least one spacing 27 separates at least two adjacent tabs 25 of the plurality of tabs 25 and each tab 25 may not be connected to another tab 25 other than by the attachment portion.

The tabs 25 are attached to the data sheet 15 by lamination, preferably during the lamination of the plurality of body layers 18, and/or welding to the at least one body layer 18 or laminated data sheet 15. Figures 4A and 5A illustrate particularly preferred embodiments of the laminar structure 19 in which the tabs 25 are at least partially located between two adjacent body layers 18 prior to lamination. The laminar structure 19 is laminated to form the security sheet 11, as shown in Figures 4B and 5B, in which the body layers 18 are fused to one another to form the data sheet 15 and the tabs 25 are located substantially within the data sheet 15. During lamination the material of two body layers 18 adjacent to and overlying the adjacent tabs 25 flows or is pressed through the at least one 7 -spacing 27. As a result, material of the data sheet 15 at least partially fills at least one spacing 27 between at least two adjacent tabs 25, which are therefore embedded in the data sheet 15. Preferably every spacing 27 between adjacent tabs 25 is filled with material of the data sheet 15 to ensure a strong connection.

Figures 6A and 7A illustrate further embodiments of the laminar structure 19 in which the tabs 25 are located on the first or second outer surface 28, 29 of the at least one body layer 18. In the data sheet 15, as illustrated in Figures 6B and 7B, the tabs 25 are at least partially attached at or adjacent to an outer surface of the data sheet 15. The tabs 25 may be laminated and pressed into the first or second outer surface 28, 29 during lamination of the plurality of body layers 18. Alternatively, before or after lamination of the plurality of body layers 18, the tabs 25 may be welded into the first or second outer surface 28, 29. In each method the material of the at least one body layer 18 flows or is pressed through the at least one spacing 27 to form the connection such that the tabs 25 are embedded in the data sheet 15. The lamination or welding preferably presses the tabs 25 into the first or second outer surface 28, 29 sufficiently deeply that substantially all of the tabs 25 are not exposed and are covered by the material of the at least one body layer 18.

The tabs 25 are therefore firmly connected to the at least one body layer 18 by a frictional force applying a resistance to the attempted removal of the attachment layer 17 from the data sheet 15. Preferably the tabs 25 comprise a different material to the surrounding material of the data sheet 15 such that a discrete boundary or frictional contact surface is formed between them. The tabs 25 may thus comprise a material of a higher melting point to that of adjacent body layers 18 and, during lamination or welding, the tabs 25 do not melt or fuse to the body layers 18. However, alternatively or in addition, the tabs may be at least partially bonded to the data sheet 15 by fusing, adhesion and/or the like with the body layers 18 to further improve the strength of the connection.

Preferably the contact surface area is relatively large to improve the strength of the connection. Therefore, as shown in Figures 3 and 8 to 15, preferably each of the plurality of tabs 25 is separated from an adjacent tab 25 by a spacing 27. However, unavoidably during manufacture or by design one or more tabs 25 may overlap one or more adjacent tabs 25. Therefore, preferably at least 50%, more preferably at least 75%, more preferably at least 90% or more preferably at least 95% of the plurality of tabs 25 are separated from their adjacent tab 25 by a spacing 27. Further preferably the attachment layer 17 comprises 8 -at least five tabs 25, more preferably at least ten tabs 25, more preferably at least twenty tabs 25 and, yet more preferably, at least fifty tabs 25.

Preferably the tabs 25 extend substantially entirely across the data sheet 15, as illustrated in Figures 4A, 4B, 7A, 7B, 8, 13A, 13B and 15. However, the tabs 25 may extend only partially across the data sheet, as illustrated in Figures 3, 5A, 9, 6A, 6B, 10, 11, 12 and 14. Preferably the tabs 25 and spacings 27 extend from the inner edge 22 of the data sheet 15 across at least 25%, more preferably at least 50%, more preferably across at least 75% and yet more preferably at least 90% of the data sheet 15 to the outer edge 23 of the data sheet 15 (i.e. across the data sheet 15 in a direction substantially perpendicular to the fold line 12).

The size of the at least one spacing 27 is selected to enable a suitably large volume of material of the data sheet 15 to flow, bond and/or fuse between the tabs 25 to provide resistance to delamination of the data sheet 15. Preferably, the average width of at least one spacing 27 may be at least or greater than the average width of the tab(s) 25 adjacent to the at least one spacing 27. Alternatively, width of at least one spacing 27 may be at least or greater than the maximum width of the tab(s) 25 adjacent to the at least one spacing 27. The width of a spacing 27 may be the distance between adjacent tabs 25 in a direction substantially parallel to the fold line 12 and/or the width of a tab 25 may be the distance between the opposing outer edges of a tab in a direction substantially parallel to the fold line 12. The maximum and/or average width of the at least one spacing 27 is preferably at least approximately 0.5 mm, more preferably at least approximately 1 mm, more preferably at least approximately 2 mm, and yet more preferably at least approximately 5 mm. The width of the spacings 27 may also vary across the attachment layer 17.

Various arrangements of the attachment layer 17 fall within the scope of the present invention. In Figures 3 and 8 the attachment layer 17 at least partially comprises a textile.

The attachment portion 26 comprises a woven textile having interlaced warps 30 and wefts 31. The wefts 31 preferably extend substantially parallel to one another, the fold line 12 and/or the inner edge 22 of the data sheet 15. The warps 30 preferably extend substantially parallel to one another and/or are preferably substantially perpendicular to the wefts 31, inner edge 22 of the data sheet 15 and/or the fold line 12. It will be appreciated that the warps 30 may be termed as the wefts 31, depending upon orientation of the attachment layer 17, and that the terms used herein are merely used for the sake of nomenclature. The tabs 25 also comprise portions of the warps 30 extending out of the woven textile of the attachment portion 26. In particular, the tabs 25 comprise the portions of the warps 30 extending from the weft 31 distal to the fold line 12 and/or proximate the inner edge 22 of the data sheet 15.

In Figure 3 the textile comprises threads forming the warps 30 and wefts 31. For example, the threads may comprise at least one of cotton, polyamide, polyester, viscose, glass, polypropylene, polyaramid, polyurethane and/or other suitable fibres. Each thread may be substantially circular, trilobal, fibrillated, grooved, dogbone or multiform in cross section. Each thread may have a diameters in the range of from approximately 26 microns up to approximately 300 microns. The spacings 27 between the threads may have a width in the range of from approximately 18 microns up to approximately 200 microns. The woven threaded textile of the attachment portion 26 is particularly suitable as it is very flexible and resistant to plastic deformation. As the thread warps 30 form a large number of tabs 25, the contact surface area between the tabs 25 and data sheet 15 is particularly high.

In Figure 8 the textile comprises strips forming the warps 30 and wefts 31. The strips may comprise, for example, polyester, polyamide, cotton, polyamide, polyester, viscose, glass, polypropylene, polyaramid, polyurethane and/or the like. The width of the strips is preferably in the range of from approximately 0.5 mm to approximately 10 mm.

The attachment layer 17 may be formed by weaving the weft threads 31 through just part of the warp threads 30. However, preferably the method of forming the attachment layer 17 comprises removing part of the weft threads from a fully woven textile, thereby exposing the portions of the warp threads 30 for forming the tabs 25 (or alternatively removing part of the warp threads from a fully woven textile thereby exposing the portions of the weft threads). As illustrated in Figure 9, which shows a cross-section of part of the data sheet 15 after lamination, the exposed portions of the warp threads 30 therefore have undulations where they were pressed by the weft threads originally in the woven textile.

These undulations form a sinusoidal path through the thickness of the data sheet 15, thereby increasing resistance to removal of the attachment layer 17. Alternatively, the woven textile may be formed such that at least part of the weft threads are soluble in a liquid, such as water, and these weft threads are removed by dipping the woven textile in the liquid.

-10 -Figures 1010 15 illustrate further embodiments in which the attachment layer 17 comprises at least one film layer 40. In particular, the attachment portion 26 comprises an elongate body 41 of the at least one film layer 40, which is preferably substantially solid or continuous, and preferably extends parallel to the fold line 12 and inner edge 22 of the data sheet 15. Each tab 25 is comprised of the at least one film layer 40 and extends from the elongate body. The at least one film layer 40 may comprise a plurality of film layers 40 laminated or otherwise bonded together and may compriseat least one of polyamide, polyester, polybutylene terephthalate and polyurethane. The benefit of using at least one film layer 40 is that the tabs 25 can have a variety of different shapes to assist in connecting the attachment layer 17 to the data sheet 15. Furthermore, when the data sheet is viewed in transmitted light by the naked eye, the tabs 25 may have a different opacity to the rest of the data sheet 15 such that they are visible and distinguishable compared to the rest of the data sheet 15 (e.g. as shadows).

As illustrated in Figures 10, 11, 12 and 15 at least one or all of the plurality of tabs may taper outwardly away from the attachment portion 26 such that it or they are wider distal to the attachment portion 26 than proximate the attachment portion 26. The tabs 25 therefore provide further resistance to removal from inner edge 22 of the data sheet 15 as they would need to be compressed along their width in order to be removed. Alternatively, at least one or all of the plurality of tabs 25 may taper inwardly away from the attachment portion 26 such that it or they are narrower distal to the attachment portion 26 than proximate the attachment portion 26. Therefore, the spacings 27 are larger within the data sheet 15 and thus provide improved delamination resistance.

As illustrated in Figures 11 and 12, at least one or all of the plurality of tabs 25 may comprise at least one aperture 42. During connection of the attachment layer 17 to the data sheet 15 the material of the data sheet 15 may flow or be bonded or fused through the at least one aperture 42, thereby providing further resistance to the removal of the attachment layer 17 from the data sheet 15.

As illustrated in Figure 12, at least one or all of the plurality of tabs 25 may comprise at least one indentation 43 on at least one edge. A pair of indentations 43 as illustrated may be located opposite one another on the at least one tab 25 such that the at least one tab 25 has an hourglass shape. Thus the material of the data sheet 15 extends into the at least one indentation 43 to further resist removal of the attachment layer 17.

As illustrated in Figures 13A to 15, at least one or all of the plurality of tabs 25 may comprise a strip of the at least one film layer 40 extending from the attachment portion 25. Preferably at least one strip extends at an acute angle, such as approximately 45 degrees, to the fold line 12, inner edge 22 of the data sheet 15 and/or sides of the data sheet 15 as shown in Figures 13A, 13B and 15 in order to provide further resistance to their removal.

Alternatively, at least one strip extends perpendicular to the fold line 12 and/or inner edge 22 of the data sheet 15 and/or parallel to the sides of the data sheet 15 as shown in Figure 14, which may be simpler to manufacture. The strips are preferably parallel to one another.

The attachment layer 17 may comprise at least one cross support 45 extending across and attached to or formed with at least two tabs 25, and preferably all of the tabs 25, as illustrated in Figures 13A, 13B and 14. Figure 13A shows a laminar structure 19 prior to lamination for forming a plurality of security sheets 11 during a continuous process from at least one elongate body layer 18 and an elongate attachment layer 17, which may be fed from rolls or the like. A cross support 45 is attached at the ends of the tabs 25 distal to the attachment portion 26. At least the cross support 45, in this case also portions of the tabs 25, extends from the outer edge 23 of the at least one body layer 18. The at least one cross support 45 ensures that the tabs 25 do not overlap during manufacture. Once the attachment layer 17 has been located on or between the at least one body layer 18, and preferably after lamination, at least the cross support 45, and in this case also portions of the tabs 25 extending from the data sheet 15, is cut from the attachment layer 17. Figure 13B shows the subsequently formed security sheet 11 in which the data sheet 15 and attachment layer 17 have also been cut from the laminar structure 19 of Figure 13A. As in Figure 14 the at least one cross support 45 may be located within the data sheet 15 such that cutting is not required.

The at least one cross support 45 may have any suitable form, such as a strip as in Figures 13A and 14 and may be formed by the punching of the at least one spacing 27 from the at least one film layer 40. Alternatively the at least one cross support 45 may comprise at least one weft of a textile (or at least one warp of a textile, depending upon orientation and nomenclature of the attachment layer 17). Further alternatively, the at least one cross support 45 may comprise a tape or strip of at least one film layer extending across, above and/or below, the tabs 25 and bonded thereto, such as by lamination, welding or adhesive, the warps or wefts. However, at least one spacing 27, which may be considered to extend between two adjacent tabs 25 from the attachment portion 26 to the at least one cross support 45, is still preferably suitably large to allow a high volume of -12 -material of the data sheet 15 to flow through it. In general, including embodiments with at least one cross support 45, the at least one spacing 27, and preferably all of the spacings 27, may extend between adjacent tabs 25 across at least 5%, more preferably across at least 10%, more preferably across at least 25%, more preferably across at least 50%, more preferably across at least 75% and yet more preferably at least 90% of the distance from the inner edge 22 of the data sheet 15 to the outer edge 23 of the data sheet 15 and between the tabs 25.

The attachment portion 26 and tabs 25 may be formed from any combination of the arrangements disclosed herein. For example, as in Figure 15, some tabs 25 may comprise strips and some tabs may taper outwardly. In further embodiments at least one tab 25 comprises at least one barb configured to resist outward movement of the attachment layer 17, preferably by the at least one bard embedding itself in the data sheet 15 during an attempted removal. The attachment portion 26 may comprise a nonwoven textile and each tab 25 may comprise a strip of warps and wefts of the nonwoven textile or a single warp of the nonwoven textile. At least one tab 25 may extend in to the data sheet 15 the shape of a spiral, symbol, logo or the like.

The tabs 25 may extend across the data sheet by the same (as illustrated) or different distances. For example, the ends of the tabs 25 distal to the inner edge 22 may form a sinusoidal path or the like. The ends of the tabs 25 may form patterns visible to the naked eye in the data sheet 15 in reflected and/or transmitted light incident thereupon.

The attachment layer 17 may also comprise the textile discussed above embedded in at least one film layer. For example, the attachment portion 26 may be at least partially embedded in at least one film layer. The at least one film layer may extend from the textile of the attachment portion 26 into the body layers 18 and may be laminated with the body layers 18 to form the security sheet 11.

Furthermore, in the embodiments in which the attachment layer 17 extends across the entire data sheet 15, such as in Figures 4A, 7A, 9 and 15, prior to lamination of the at least one body layer 18 the tabs 25 may extend beyond the outer edge 23 in a similar manner to that shown in Figure 13A. Prior to or after lamination the excess portions of the tabs 25 are cut away. However, cutting the tabs 25 at the edges of the data sheet 15 may result in them being exposed at the edges, thereby forming discrete boundaries at which a sharp implement can be inserted by a counterfeiter to attempt delamination. As a result, in -13 -preferred embodiments, the tabs 25 exposed at the edges of the data sheet 15 are sealed to the data sheet 15. The sealing may be achieved by lamination or welding directly onto the edges such that material of the data sheet 15 flows over the exposed tabs 25. Alternatively, additional portions of the same material as the data sheet 15 may be located adjacent to at least one edge of the at least one body layer 18 and laminated thereto during the main lamination of the laminar structure 19.

At least some tabs 25 may be attached at the first outer surface 28, at least some tabs 25 may be attached at the second outer surface 29 and/or at least some tabs 25 may be attached within the thickness of the data sheet 15 (i.e. combinations of the arrangements of Figures 4A to 7B).

The tabs 25 may be attached to the first or second outer surface 28, 29 by adhesion. For example, the tabs 25 may be located on the first or second outer surface 28, 29 and an adhesive applied to them. The adhesive may comprise a solution or a film (comprising, for example, polyurethane) that fuses through the tabs 25 and with the data sheet 15.

In the illustrated embodiments the attachment portion 26 is entirely located outside of the data sheet 15. Such an arrangement is preferred as it reduces the size of the discrete boundary between the attachment layer 17 and data sheet 15 at the inner edge 22 such that delamination is less likely. However, the tabs 25 need to be particularly resistant to tearing along the inner edge 22 in such an arrangement, although it has been found that the aforementioned embodiments are sufficient in the case of a passport. In order to further improve resistance to tearing along the inner edge 22 the attachment portion 26 may extend partly into the data sheet 15, such as by being located between or on at least one body layer 18. For example, the attachment portion 26 may extend into the data sheet 15 up to 25%, more preferably up to 10% and more preferably up to 5% of the distance from the inner edge 22 to the outer edge 23 of the data sheet 15.

The attachment layer 17 may comprise at least one security feature located in or on the attachment portion 26 and/or at least one tab 25 or bridging the attachment portion 26 and the tabs 25 so it runs from one section into the other. Such security features may comprise, for example, laser marking, printed ink, holograms, security fibres, security planchettes, security threads, holograms and the like. The tabs 25 and/or attachment portion 26 may comprise a material with inherent security properties, such as by being -14 -formed from a polymer and/or with a fluorescent, phosphorescent, photochromic, thermochromic or the like additive. The tabs 25 and/or attachment portion 26 may be metallised and/or comprise features formed by demetallisation.

In the illustrated embodiment the attachment layer 17 is attached to a single data sheet 15 and extends only partially from the fold line 12 into the side of the security document 10 opposing the data sheet 15. In other embodiments a second data sheet 15 is attached to the opposing end of the attachment layer 17, in a similar manner or different manner to that disclosed herein. The attachment layer 17 may also extend across the entire side of the security document 10 opposite to the data sheet 15.

The data sheet 15 may comprise further security features in addition to the data 16. For example, the data sheet 15 may comprise an RFID chip and/or antenna, laser marking, printed ink, holograms, security fibres, security planchettes, security threads, holograms and the like. One or more of the body layers 18 may be at least partially transparent and/or opaque. In particular, at least part of the tabs 25 extending into the data sheet 15 may be hidden from view to the human eye in reflected and/or transmitted light incident upon the first and/or second outer surface 28, 29.

The present disclosure provides, in accordance with the following clauses: 1. A security sheet comprising: a data sheet for displaying data; and an attachment layer comprising a plurality of tabs extending from an attachment portion for attaching the data sheet into a security document, wherein the plurality of tabs are attached to the data sheet such that the attachment layer is attached to and extends from the data sheet.

2. A security sheet as in clause 1 wherein the plurality of tabs are attached to the data sheet by being at least partially embedded in the data sheet.

3. A security sheet as in clause 2 wherein at least one spacing separates at least two adjacent tabs of the plurality of tabs and the plurality of tabs are at least partially embedded in the data sheet by material of the data sheet at least partially filling the at least one spacing.

4. A security sheet as in any one of the preceding clauses wherein the security sheet comprises data elements in or on the data sheet and the plurality of tabs at least partially overlap the data elements.

5. A security sheet as in any one of the preceding clauses wherein the data sheet is formed from at least a plurality of body layers and at least one tab of the plurality of tabs is attached between two body layers.

6. A security sheet as in any one of the preceding clauses wherein the at least one tab of the plurality of tabs is attached at or adjacent to an outer surface of the data sheet.

7. A security sheet as in any one of the preceding clauses wherein the attachment layer comprises a textile and/or at least one film layer.

8. A security sheet as in clause 7 wherein the attachment layer comprises a textile and the attachment portion comprises a plurality of warps intersecting a plurality of wefts and the plurality of tabs comprises portions of the plurality of warps extending from the plurality of wefts.

9. A security sheet as in clause 8 wherein the plurality of tabs comprise undulations in the data sheet.

10. A security sheet as in clause 7 wherein the attachment layer comprise at least one film layer, further wherein the attachment portion comprises an elongate body of the at least one film layer and/or the plurality of tabs comprise the at least one film layer and extend from the elongate body.

11. A security sheet as in clause 10 wherein at least one tab of the plurality of tabs comprises at least one aperture, tapers outwardly from the attachment portion, comprises at least one indentation in at least one edge, comprises a strip of the at least one film layer extending from the attachment portion, comprises at least one barb 12. A security sheet as in any one of the preceding clauses wherein the attachment portion is located partially or entirely out of the data sheet.

13. A security sheet as in any one of the preceding clauses wherein at least two adjacent tabs of the plurality of tabs are separated by at least one spacing and are attached to one another within data sheet by at least one cross support, the at least one spacing substantially separating the at least one cross support and attachment portion.

14. A security document comprising the security sheet of any one of the preceding clauses and at least one further leaf attached to the attachment portion.

15. A laminar structure for forming a security sheet comprising: at least one body layer for forming a data sheet for displaying data; and an attachment layer comprising a plurality of tabs extending from an attachment portion for attaching the data sheet into a security document, wherein the plurality of tabs at least partially overlap the at least one body layer such that the attachment layer extends from the at least one body layer.

16. A method of forming a security sheet comprising: -16 -locating an attachment layer to overlap at least one body layer, wherein the attachment layer comprising a plurality of tabs extending from an attachment portion for attaching the data sheet into a security document; and attaching the plurality of tabs to the at least one body layer such that the attachment layer is attached to and extends from the at least one body layer and the at least one body layer forms a data sheet for displaying data.

17. A method as in clause 16 further comprising attaching the attachment layer to the at least one body layer by laminating or welding the at least one body layer such that the plurality of tabs are at least partially embedded in the at least one body layer.

18. A method as in clause 16 or clause 17 further comprising at least partially locating the plurality of tabs between adjacent body layers of the at least one body layer prior to attachment or locating the plurality of tabs to at least partially overlie an outer surface of the at least one body layer.

19. A method as in any one of clauses 16 to 18 wherein the method of forming the attachment layer comprises providing a textile comprising warps and wefts and removing a portion of the wefts from the textile to expose portions of the warps, the attachment portion comprising a plurality of warps intersecting the remaining plurality of wefts and the plurality of tabs comprising the exposed portions of the plurality of warps.

20. A method as in any one of clauses 16 to 19 wherein at least one tab of the plurality of tabs is at least partially exposed at one or more edges of the data sheet and the one or more edges are sealed to cover the at least one exposed tab.

21. An attachment layer for forming a security sheet comprising a data sheet displaying data, the attachment layer comprising: an attachment portion for attachment into a security document; and a plurality of tabs extending from the attachment portion and for attachment to the data sheet such that the attachment layer extends from the data sheet.

Claims

-17 -CLAIMS: 1. A security sheet comprising: a data sheet for displaying data; and an attachment layer comprising a plurality of tabs extending from an attachment portion for attaching the data sheet into a security document, wherein the plurality of tabs are attached to the data sheet such that the attachment layer is attached to and extends from the data sheet, wherein: the data sheet is formed from at least a plurality of body layers and at least one tab of the plurality of tabs is attached between two body layers attached to one another.
2. A security sheet as claimed in claim 1 wherein the plurality of tabs are attached to the data sheet by being at least partially embedded in the data sheet.
3. A security sheet as claimed in claim 2 wherein at least one spacing separates at least two adjacent tabs of the plurality of tabs and the plurality of tabs are at least partially embedded in the data sheet by material of the data sheet at least partially filling the at least one spacing.
4. A security sheet as claimed in any one of the preceding claims wherein the security sheet comprises data elements in or on the data sheet and the plurality of tabs at least partially overlap the data elements.
5. A security sheet as claimed in any one of the preceding claims wherein the attachment layer comprises a textile and/or at least one film layer.
6. A security sheet as claimed in claim 5 wherein the attachment layer comprises a textile and the attachment portion comprises a plurality of warps intersecting a plurality of wefts and the plurality of tabs comprises portions of the plurality of warps extending from the plurality of wefts.
7. A security sheet as claimed in claim 6 wherein the plurality of tabs comprise undulations in the data sheet.
8. A security sheet as claimed in claim 5 wherein the attachment layer comprise at least one film layer, further wherein the attachment portion comprises an elongate body of the at -18 -least one film layer and/or the plurality of tabs comprise the at least one film layer and extend from the elongate body.
9. A security sheet as claimed in claim 8 wherein at least one tab of the plurality of tabs comprises at least one aperture, tapers outwardly from the attachment portion, comprises at least one indentation in at least one edge, comprises a strip of the at least one film layer extending from the attachment portion or comprises at least one barb.
10. A security sheet as claimed in any one of the preceding claims wherein the attachment portion is located partially or entirely out of the data sheet.
11. A security sheet as claimed in any one of the preceding claims wherein at least two adjacent tabs of the plurality of tabs are separated by at least one spacing and are attached to one another within the data sheet by at least one cross support, the at least one spacing substantially separating the at least one cross support and attachment portion.
12. A security document comprising the security sheet of any one of the preceding claims and at least one further leaf attached to the attachment portion.
13. A method of forming a security sheet comprising: locating an attachment layer to overlap at least one body layer, wherein the attachment layer comprises a plurality of tabs extending from an attachment portion for attaching the data sheet into a security document, wherein the plurality of tabs are at least partially located between adjacent body layers of the at least one body layer; and attaching the plurality of tabs to the at least one body layer such that the attachment layer is attached to and extends from the at least one body layer and the at least one body layer forms a data sheet for displaying data, wherein the adjacent body layers are attached to one another and the plurality of tabs are attached between the adjacent body layers.
14. A method as claimed in claim 13 further comprising attaching the attachment layer to the at least one body layer by laminating or welding the at least one body layer such that the plurality of tabs are at least partially embedded in the at least one body layer.
15. A method as claimed in claim 13 or claim 14 wherein the method of forming the attachment layer comprises providing a textile comprising warps and wefts and removing a portion of the wefts from the textile to expose portions of the warps, the attachment portion -19 -comprising a plurality of warps intersecting the remaining plurality of wefts and the plurality of tabs comprising the exposed portions of the plurality of warps.
16. A method as claimed in any one of claims 13 to 15 wherein at least one tab of the plurality of tabs is at least partially exposed at one or more edges of the data sheet and the one or more edges are sealed to cover the at least one exposed tab.