GB2531584A

GB2531584A - Improvements in security papers and documents

Info

Publication number: GB2531584A
Application number: GB1418860.1A
Authority: GB
Inventors: Mclean Henderson Peter; Charles Sugdon Matthew; Stewart Georgina
Original assignee: De la Rue International Ltd
Current assignee: De la Rue International Ltd
Priority date: 2014-10-23
Filing date: 2014-10-23
Publication date: 2016-04-27
Anticipated expiration: 2034-10-23
Also published as: GB201418860D0; WO2016063049A1; GB2531584B; EP3209831A1

Abstract

The present invention is directed towards a security paper 10 comprising at least one layer 11 of fibrous substrate and a security additive 14 embedded within the fibrous substrate. The security additive is located within a predetermined region of the at least one layer and at least 75% of the security additive in the predetermined region is fully embedded within the at least one layer. The security additive is detectable when the fibrous substrate is split, thereby exposing the security additive. A security document comprising the security paper is also claimed, wherein the security document is selected from a banknote, a cheque, a certificate, a passport, a passport page, an identification card and a drivers licence. The present invention further provides a method of manufacturing the security paper, wherein the method comprises depositing fibres to form a fibrous substrate on a support surface; depositing the security additive on an initial layer of fibres; depositing further fibres over the security additive and the initial layer to form an integral layer of fibrous substrate; couching the layer of fibrous substrate and security additive from the support surface; and drying the layer of fibrous substrate and security additive.

Description

IMPROVEMENTS IN SECURITY PAPERS AND DOCUMENTS

The present invention is directed towards a security paper comprising at least one layer of fibrous substrate and a security additive embedded within the layer. The present invention further provides a method of manufacturing the security paper and security documents made from the security paper.

Security documents and booklets such as passports, passbooks, identification documents, certificates, licences and cheque books commonly comprise one or more data pages on which information is provided. For example, as disclosed in WO-A-2010/040987, a passport booklet typically comprises a cover (having a front and a back) and a plurality of internal pages (sometimes kncwn as visa pages) therebetween. Typically the visa pages are made from paper having a grammage of around 85 gsm and are sewn together. The cover is adhered to the outside of the visa pages and thereby protecting the stitch line. An RFID chip or similar device can be provided within the cover for electronic detection and further security.

At least one data page is provided integrally with one of the visa pages, usually sewn into the stitch line and/or as part of the cover. The data pages commonly comprise one or more base layers of a fibrous substrate, such as paper, overlaid by a layer of polymer laminate, usually applied as a film or lacquer. The fibrous substrate layers are usually made, for example, from paper or cotton fibres and usually have a grammage of around 110 gsm.

The base layer typically has a number of security features, such as watermarks and machine readable printing. In particular, cylinder mould or electrotype watermarks may be formed in the fibrous substrate during manufacture.

Personalised information relating to the owner of the security document, such as their name, address, nationality, date of birth and photograph, may be subsequently printed onto the base layer before the laminate layer is applied.

The laminate layer usually has one or more further security features, such as holograms, colour changing inks or other optically variable elements. Holograms can be provided in alignment with the personalised information and/or security features of the base layer. For example, the laminate layer may be arranged to make a watermark in the base layer visible only when viewed from certain angles. The laminate layer is attached tc the fibrous substrate by an adhesive, which prevents the removal of the laminate layer without destroying the personalised information printed on the base layer.

However, it has been found that counterfeiters are able to manufacture counterfeit security documents from original security documents by splitting the base layer through the plane of the ply. This enables the laminate layer and personalised information to be separated from the part of the base layer containing one or more security elements, such as a watermark. The counterfeiter can print new personalised information on this part of the base layer and then apply a new laminate layer containing reproduced security features within it. As a result, the reproduced data page will include a base layer having some of the security features of the original base layer.

WO-A-2011/110799 addresses the problem of counterfeiters splitting banknotes in two along the plane of the note and subsequently forming a counterfeited banknote comprising the front of the genuine note adhered to the back of a counterfeit note. In WO-A-2011/110799 a security substrate is provided with two sets of regions, one set being located on either surface of the substrate, and both of which are required to be present to form a machine readable code. If the banknote is split, the machine readable code will not be formed and the counterfeit can be recognised. However, such an arrangement is not suitable in security documents not having a machine readable code and/or not having the sets of regions on both sides of the security substrate. This is particularly the case for passports, although is also applicable to other security documents.

An object of the present invention is to improve the security of security documents by preventing adaptation by counterfeiters, whether by splitting or other means, and by improving the ability of any such adaption to be recognised by a machine or eye.

The present invention therefore provides a security paper comprising: at least one layer of fibrous substrate; and a security additive substantially embedded within the fibrous substrate and located within a predetermined region of the at least one layer, at least 75% of the security additive in the predetermined region being fully embedded within the at least one layer, wherein the security additive is detectable when the fibrous substrate is split, thereby exposing the security additive.

In a preferred embodiment the predetermined region extends through the thickness of the at least one layer. Preferably the predetermined region extends over the whole of the layer or only partially extends over the layer in a shape or an elongate strip extending from a first edge to an opposing second edge of the security paper.

Preferably at least 90% of the security additive in the predetermined region is fully embedded within the layer. The security additive is preferably not substantially detectable at the surfaces of the security paper by a machine.

Furthermore, the security additive is not substantially visible the naked eye when the security paper is viewed in reflected and/or transmitted light.

In a particular embodiment the security additive is substantially hydrophilic or hydrophobic. Further preferably the security additive is arranged to provide a coloured, metallic, photochromic, iridescent, luminescent, fluorescent, infrared transmitting and/or the like effect.

In preferred embodiments the security additive comprises at least one of a plurality of security fibres, a plurality of security particles, a plurality of planchettes and/or a colourant.

In the case of security fibres, the length of the security fibres preferably lies in the range 1 to 10 mm, more preferably 2 to 7 mm long and yet more preferably 3 to mm. The width of the security fibres preferably lies in the range 20 to 100 um, and is preferably approximately 50 2m. The security fibres are preferably dyed, printed upon and/or coated with suitable chemical compositions to provide the coloured, metallic, photochromic, iridescent, luminescent, fluorescent, infrared transmitting and/or the like effect.

Preferably a shape of the planchettes is a symbol, logo 10 or other shape conveying recognisable information. The colourant preferably comprises a dye and/or a pigment.

The security paper also preferably comprises at least one further security feature selected from a watermark, an 15 electrotype, print and/or a security thread.

In particular embodiments the security paper comprises a single layer of fibrous substrate. Preferably the single layer has a grammage of between approximately 80 and 200 gsm 20 or between approximately 100 and 150 gsm.

In an alternative embodiment the security paper comprises a first and a second layer of fibrous substrate, the first layer comprising the security additive and having 25 a higher grammage than the second layer.

The invention further provides a security document comprising the aforementioned security paper. The security document is preferably a document of value selected from a banknote, a cheque, a certificate, a passport, a passport page, an identification card and a drivers licence.

In preferred embodiments the security document comprises: personalised data printed on the security paper; and a protective layer provided over the personalised data and attached to the security paper. Preferably the protective layer is a laminate film or a lacquer layer.

The invention yet further provides a method of manufacturing the security paper of the present invention, the method comprising the steps of: depositing fibres to form fibrous substrate on a support surface; depositing the security additive on an initial layer of fibres; depositing further fibres over the security additive and the initial layer to form an integral layer of fibrous substrate; couching the layer of fibrous substrate and security additive from the support surface; and drying the layer of fibrous substrate and security additive.

In a preferred embodiment the support surface rotates in a vat of fibrous stock, the fibrous stock having an upper surface and the security additive being provided on the initial layer at a predetermined distance below the upper surface.

Preferably the initial layer of fibrous substrate is 25 formed at a predetermined distance below the upper surface. The predetermined distance is, in particular, 50 mm to 1000 mm.

In preferred embodiments the method comprises the step 30 of combining the layer of fibrous substrate with a second layer of fibrous substrate, said second layer of fibrous substrate being formed in a separate forming step.

By way of example only, embodiments of a security paper, its method of manufacture and a security document incorporating the security paper are now described with reference to, and as show in, the accompanying drawings, in which: Figure 1 is a cross-sectional side elevation of a security paper of the present invention; Figure 2 is a perspective view of the security paper of Figure 1; Figure 3 is a perspective view of the security paper of Figure 1 being split through the plane of the security paper such that a security additive therein is exposed; Figure 4 is a cross-sectional side elevation of a 15 section of a paper-making machine for use in a method of manufacturing the security paper of Figure 1; Figure 5 is a detailed cross-sectional side elevation of a small section of the paper-making machine of Figure 4; Figure 6 is a cross-sectional side elevation of a 20 further embodiment of the security paper of the present invention; and Figure 7 is a cross-sectional side elevation of a section of a paper-making machine for use in a method of manufacturing the security paper of Figure 6.

Figures 1 and 2 illustrate a first embodiment of the security paper 10 of the present invention. In this embodiment, the security paper 10 is single ply and comprises a single layer 11 cf fibrous substrate which has first and second opposing planar surfaces 12, 13.

A security additive 14 is embedded and dispersed within the fibrous substrate of the layer 11 and is located within a predetermined region of the at least one layer. At least 75%, and more preferably at least 90%, of the security additive 14 in the predetermined region is fully embedded within the layer 11.

Preferably the security additive 14 is not substantially present, and thus not detectable by the naked eye and/or machine readable, at the first and second surfaces 12, 13. The security additive 14 is preferably provided substantially in a central section of the layer 11 in the predetermined region between the first and second surfaces 12, 13 (as illustrated in Figures 1 and 2).

Preferably, in the predetermined region, the security additive 14 is provided substantially entirely within the layer 11 and substantially nc security additive 14 is located at or on its first or second surface 12, 13. The security additive 14 is, therefore, not visible to the human eye when viewed in reflected light incident upon the first or second surfaces 12, 13, i.e. when the security paper 10 is viewed from the same side of the security paper 10 as a light source. In addition, the security additive 14 is preferably not detectable to a machine when first or second surface 12, 13 is interrogated by a machine (for example if the machine is searching for magnetic or electrical conductivity in the security paper 10).

It is therefore preferred that the predetermined region 30 does not extend to the first and second surfaces 12, 13. However, during manufacture cf the security paper 10, some of the security additive 14 may be embedded at or on the first or second surface 12, 13. Thus the predetermined region preferably extends between the first and second surfaces 12, 13 throughout the thickness of the layer 11 and defines a predetermined volume of fibrous substrate. The density of the security additive 14 is greater within the layer 11 and predetermined region than adjacent to or at the first and second surfaces 12, 13. Preferably the density is greater within the central 80% of the thickness of the layer 11 than within the 10% of the thicknesses of the layer 11 adjacent to each of the first and/or second surfaces 12, 13. More preferably the density is greater within the central 90% of the thickness of the layer 11 than within the 5% of the thicknesses of the layer 11 adjacent to each of the first and/or second surfaces 12, 13.

The predetermined region may extend over the whole of the layer 11 or may only partially extend over the layer 11 (i.e. in the direction orthogonal to the thickness of the layer 11). In particular the predetermined region is provided in one or more shapes, such as squares, circles, logos, symbols or the like, cr in an elongate strip extending from a first edge to an opposing second edge of the security paper 10. In a particular embodiment, the security additive 14 is provided within an elongate strip having a width lying in the range 10 to 60 mm and more preferably in the range 25 tc 50 mm. The elongate strip may extend from a first edge to an opposing second edge of the security paper 10. However, the security additive 14 may alternatively be dispersed randomly throughout the layer 11.

At least 75% of the security additive 14 in the predetermined region is fully embedded within the layer 11.

-10 -Therefore, no more than 25% cf the security additive 14 is located at or adjacent to the first and second surface 12, 13. In a more preferable arrangement at least 90% of the security additive 14 in the predetermined region is fully embedded within the layer 11, with no more than 10% of the security additive 14 being located at or adjacent to the first and second surface 12, 13.

For example, one hundred units (whether individual parts, grammes or volume of second additive 14) of a security additive 14 are located in the layer 11 in an area of 0.01 m2 on each of the first and second surface 12, 13. The predetermined region is defined as the volume of the layer 11 between the two areas. Ten to twenty-five units are visible from the first and second surfaces 12, 13 and ninety to seventy-five units are located within the layer 11 and only revealed upon splitting of the layer 11 (as will be described below).

In a further example, the security additive 14 is provided in the form of a band of security fibres (as will be discussed in further detail below). The band is approximately 40 mm wide and runs along the full length of a security paper 10 having a length of 0.125 m. The area of the band is 0.005 m' when viewed from the first or second surface 12, 13, the predetermined region being the volume therebetween. The number of individual security fibres present in this band is three hundred, providing a bulk density of 60,000 security fibres per m2. The number of security fibres present at the first and/or second surface 12, 13 will be no greater than 25% of the three hundred (i.e. seventy-five) and more preferably no greater than 10% (i.e. thirty). The remainder of the security fibres (i.e. 75%-90% or two hundred and twenty-five to two hundred and seventy) will be present within the core of the layer 11 and fully embedded therein.

Depending upon the thickness of the layer 11 and the size or composition of the security additive 14, it may or may not be visible in transmitted light, i.e. when the security paper 10 is viewed from the opposing side of the security paper 10 to a light source. Preferably the security additive 14 is not visible in transmitted light to avoid detection by a counterfeiter. This can be achieved by ensuring that the security additive 14 is of a similar opacity to the layer 11 of fibrous substrate.

The security additive 14 comprises one or more physical entities carrying one or more security features of a suitable composition and preferably comprises a plurality of security fibres, security particles, planchettes and/or a colourant. The security fibres, planchettes and/or particles may be of any type and/or size suitable which are visible to the human eye and/or machine readable when not embedded within the layer of fibrous substrate 11. A mix of different types and sizes of security fibres, planchettes and/or particles may be provided to improve the different security elements of the security additive 14 and thus security paper 10.

The term "security fibres" is known in the art and generally refers to predominantly fibrous and elongate (i.e. substantially one dimensional shaped) elements which are distinguishable by the human eye and/or a machine from the -12 - layer 11 forming the body of the security paper 10. The density of the security fibres adjacent to the first and/or second surfaces 12, 13 is significantly less than the density of fibres embedded wholly within the layer 11. EP-B- 2342085, which is incorporated herein by reference, discloses particularly suitable security fibres.

Security fibres are usually made from materials such as paper, silks, polyester, nylon, rayon and/or other artificial fibres. The security fibres (and any other form of security additive 14) may be arranged to produce coloured, metallic, photochrcmic, iridescent, luminescent, fluorescent, infrared transmitting and/or the like effects. The security fibres may be dyed, printed upon and/or coated with suitable chemical compositions to achieve such effects. For example, as in EP-B-2342085, the security fibres may be formed of paper strips comprising printed regions of different colours and unprinted regions.

In addition, the security fibres (and any other suitable form of security additive 14) may be machine readable, but not readily visible to the naked eye when viewed in reflected light incident on the fibres and/or transmitted light. For example, the security fibres may be magnetic or electrically conductive fibres which can be detected by electrical or magnetic detection means, such as those as disclosed in WO-A-9826379.

The security fibres preferably have a length in the range 1 to 10 mm, more preferably in the range 2 to 7 mm and more preferably in the range 3 to 5 mm. The width of the security fibres is preferably from 20 to 100 pm and more -13 -preferably approximately 50 pm. The linear density of the security fibres, particularly if formed from nylon, viscose or rayon, is preferably in a range 5 x 10 to 30 x 10-7 kg/m (5 to 30 dtex) and more preferably in a range 9 x 10 7 to 28 x 10 / kg/m (9 to 28 dtex). Such dimensions are suitable for ensuring that the security fibres are visible when not embedded in the layer 11 and not substantially visible when the security paper 10 is viewed in transmitted light.

As is known in the art, planchettes are generally formed of a small disc of paper. EP-B-2032372, the contents of which are incorporated herein by reference, discloses a method of manufacture of planchettes suitable for the present invention. The planchettes may be formed as a symbol, logo or other shape conveying recognisable information. The planchettes may be dyed, printed upon and/or coated with suitable chemical compositions to produce coloured, photochromic, iridescent, luminescent, fluorescent, infrared transmitting and/or the like effects.

In a similar manner to the security fibres, the maximum dimension of the planchettes is preferably in the range 1 to 10 mm, more preferably in the range 2 to 7 mm and more preferably in the range 3 to 5 mm.

Colourants generally comprise chemical agents to produce coloured, photochromic, iridescent, luminescent, fluorescent, infrared transmitting and/or the like effects. The colourant may comprise a dye selected from at least one of, for example, a direct dye, an acid dye or a basic dye.

The dye may include one or more florescent agents which display a coloured effect under ultraviolet or infrared light. Alternatively or in addition, the colourant may -14 -comprise a pigment selected from at least one of, for example, an organic pigment, a natural or synthetic mineral pigment (such as kaolin and/or calcium carbonate and/or silica and/or titanium dioxide), an iridescent pigment (such 5 as of the mica titanium type) and plastic pigments (for example hollow plastic microspheres based on a styrene polymer such as styrene acrylic). The colourant may comprise combinations of different dyes and/or pigments to produce different colours and effects. The colourant may be provided 10 as a continuous layer or in a plurality of discrete, dispersed regions within the fibrous substrate 11.

When the security paper 10 is split, the security additive 14 is exposed at a split surface and is detectable, as in Figure 3.

A coloured security additive 14 may be visible to the naked eye when viewed in reflected light in the visible light spectrum. In this specification the term visible light spectrum refers to electromagnetic waves having a wavelength of between approximately 400nm and approximately 700nm. If the security additive 14 is, for example, fluorescent, it may only be visible in ultraviolet light (i.e. having a wavelength of between approximately 40nm and approximately 400nm). Furthermore or alternatively, the security additive 14 may only be visible in the infrared spectrum (i.e. having a wavelength of between approximately 700nm and approximately 1000nm).

In addition, or alternatively, the security additive 14 may be substantially hydrophilic or hydrophobic such that, when exposed to liquid ink (either applied directly to the -15 -security additive 14 or to the layer 11 adjacent the security additive 14) the ink is attracted to, or repelled by, the security additive 14. As a result, the security additive 14 will disrupt the printing where they are exposed on the surface being printed. A hydrophilic or hydrophobic coating may be applied to security fibres, planchettes and/or particles by immersion, spraying or other similar processes. For example, the security additive 14 may include security fibres having a coating of hydrophobic varnish, such as is disclosed in EP-B-2342085.

The security paper 10 can additionally comprise various other security features. One such security feature is a cylinder mould watermark, in which some regions of the watermark are more dense, or thicker, than the rest of the security paper 10 and/or some regions of the watermarks are less dense, or thinner, than the rest of the security paper 10. Another security feature is an electrotype watermark, in which the some regions of the electrotype watermark are less dense than the rest of the security paper 10. Printing may also be applied to the first and/or second surfaces 12, 13 using any known printing techniques, such as dye-sublimation, screen, flexography, lithography, intaglio, gravure, dye diffusion, laser, inkjet toner, letterpress and toner transfer. Security threads and patches are another suitable security feature which may be applied to a surface of the layer 11 or embedded therein in any known manner, such as by being partially embedded therein, being fully embedded therein and/or being exposed at windows in the surface of the layer 11.

-16 -The security paper 10 may be used to produce security documents. In one particular embodiment, the security paper 10 may be used in a passport, wherein personal data and/or a machine readable zone are printed onto the first surface 12.

Personal data can comprise any suitable data relating to the owner of the passport, such as their name, address, nationality, date of birth and photograph. The machine readable zone can comprise printed letters, numbers and/or other symbols, which can be scanned and processed using 10 optical recognition to retrieve (possibly coded) data.

In a passport, a protective layer, typically approximately 10pm thick, is usually provided on the first surface 12 of the security paper 10, over the personal data and machine readable zone. The protective layer may be substantially transparent and may comprise a laminate film or lacquer layer. The lacquer layer may be applied directly to the layer 11, or via a transfer layer. The laminate film is preferably a polymeric, self-supporting layer, applied to the first surface 12 using adhesive and/or heat sealing. Preferably, the protective layer includes one or more security features, such as hclograms, colour changing inks or other optically variable elements to make it more difficult to reproduce by a counterfeiter. The security features may be applied using a transfer layer such that they are provided underneath the protective layer. Thus the protective layer protects against wear of the security paper 10 as well as providing a security function to the passport.

Typically a counterfeiter would attempt to adapt the security document such that the personalised information and/or machine readable code relates to a different person -17 -other than the original owner of the security document, but retain the security features (particularly the identification feature) provided in the layer 11 to avoid detection. To do so, they would attempt to split the security paper 10, along a split plane between the first and second surfaces, into a first portion and a second portion. The first portion, which includes the first surface 12, at least part of the layer 11 and any security additive 14 therein, is discarded by the counterfeiter. The counterfeiter would then attempt to reuse the second portion, which includes the second surface 13 and at least part of the layer 11, by applying new personalised information thereon.

The split plane is a plane of failure typically inherent within layers of fibrous substrate of at least 40 gsm and above. Typically the split plane is towards the centre of a layer of fibrous substrate (i.e. midway between its surfaces) and is substantially parallel to the opposing surfaces of the layer. Therefore, as illustrated in Figure 3, the split plane will tend to be towards the centre of the layer 11.

If the security paper 10 is split through the split plane of layer 11 (i.e. between the first and second outer surfaces 12, 13 as in Figure 3), the security additive 14 will be exposed on the second portion. It will therefore be possible to view the security additive 14 in visible light, or under appropriate lighting conditions (for example UV light or in infrared), depending upon the type of security additive 14. As a result, any counterfeited security documents incorporating the split security paper 10 can be -18 -readily identified. Furthermore, if the security additive 14 is substantially hydrophilic or hydrophobic, it will not be possible to effectively print new personalisation data or machine readable code on second portion. If attempted by a counterfeiter, they would significantly increase the likelihood of detection.

Figures 4 and 5 illustrate a section of a cylinder mould papermaking machine 20 suitable for use to manufacture the security paper 10 of the first embodiment of the present invention. The machine 20 comprises a cylinder mould 21 rotating in a vat 22 of aqueous fibrous stock 23. The cylinder mould 21 is covered with a porous support surface, such as a porous wire mesh, which forms a cylinder mould cover 24. As is well known, the cylinder mould cover 24 may comprise embossed regions 25 to form cylinder mould watermarks in the security paper 10. Electrotypes, in the form of thin pieces of metal attached to the cylinder mould cover 24, can also be provided to form electrotype watermarks (i.e. light tonal regions) in the security paper 10. Such an electrotyping process is well known in papermaking and has been described in US-B-1901049 and US-B2009185. A security thread may also be fed into the fibrous substrate 11 as it forms on the cylinder mould cover 24.

The fibrous stock 23 may comprise a range of fibre types, including synthetic or natural fibres, or a mixture of both. The actual preparation of the fibres is unrestricted by the invention, and will depend upon the effect desired in the fibrous substrate layer 11. As a general consideration, security paper 10 used for security documents, such as banknotes, passports, identification -19 -cards and so on, needs to be hard wearing, resilient, and self-supporting, and so an appropriate fibre mix is preferably selected. The layer 11 may be of any grammage, but a grammage of at least 110 gsm is preferred. Such a grammage enables a variety of different sizes and types of security additive 14 to be enbedded within the layer 11.

As the cylinder mould 21 rotates, the liquid within the fibrous stock 23 passes through the porous support surface 10 of the cylinder mould cover 24. The fibres are deposited on the support surface and the layer 11 is thereby formed.

At a position within the vat 22 where an initial thin layer of the fibrous substrate has been formed on the cylinder mould cover 24, the security additive 14 is injected into the vat adjacent to the cylinder mould cover 24. For example, the thin layer of fibrous substrate may have a grammage of around 30 to 50 gsm on the cylinder mould cover 24 at this position. As illustrated, in an embodiment an additive injector 26, such as in the form of a thin tube, receives the security additive 14 from a security additive reservoir (not shown) and injects it into the fibrous stock 23. A pump is provided to draw the security additive 14 from the reservoir and direct it along the additive injector 26. 25 The security additive 14 is drawn to, and to a degree mixes with, the thin layer of fibrous substrate formed on the cylinder mould cover 24 by the pressure difference created adjacent thereto by the rotation of the cylinder mould 21. In particular, where the predetermined region is to be in the form of a stripe of security additive 14, the additive injector 26 injects security additive 14 over a -20 -restricted distance along the axis of rotation of the cylinder mould cover 24. However, if the predetermined region extends across the entire layer 11, the additive injector 26 extends all the way along the cylinder mould cover 24 along its axis of rotation, or a plurality of additive injectors 26 are provided.

Preferably the flow of fibrous stock 23 towards the cylinder mould cover 24 is as laminar as possible at the initial point of formation of the layer 11 thereon. A laminar flow ensures that the layer 11 forms with optimum fibre orientation. Furthermore, if a stripe or similar predetermined region of security additive 14 is being formed, a laminar flow assists in ensuring that the edges of the stripe or predetermined region are neat and straight.

A suitable method for forming such a laminar flow is to delay the formation of the fibrous stock 23 such that the initial formation point 27 is below the top surface of the fibrous stock 23 in the vat. For example, and as illustrated in Figures 4 and 5, a sealing means 28 may be provided to form a seal with the cylinder mould cover 24 below the top surface of the fibrous stock 23. The seal prevents fibrous substrate forming on the cylinder mould cover 24 above it.

The sealing means 28 may comprise a plastic sheet or the like, which is sufficiently hard wearing to prevent disintegration through continuous contact with the cylinder mould cover 24. Alternatively, a baffle may be provided adjacent to, but not sealed to, the cylinder mould cover 24 to allow only a small amount of fibrous substrate to form thereon until the initial formation point 29 illustrated.

-21 -In the vat 22 the fibrous stock 23 will tend to be less turbulent below its surface and, with the initial formation point 27 below the surface, the laminar characteristics of the flow of fibrous stock 23 towards the cylinder mould cover 24 will be improved. In addition, liquid pressure or head is generated adjacent tc the initial formation point 27 and assists in forming the laminar flow, as well as increasing the rate at which the layer 11 forms on the cylinder mould cover 24. For example, suitable head has been found to be generated when the initial formation point 27 is arranged to be 50 mm to 1000 mm below the surface, and more preferably 50 mm to 500 mm below the surface.

Once the security additive 14 has been deposited on the initial thin layer of fibrous substrate, the rest of the layer 11 is formed by depositing further fibres thereon. If the predetermined region extends between the first and second surfaces 12, 13, these later deposited fibres will contain some security additive 14. In regions where there is no security additive 14 present, further fibres are deposited directly on the initial thin layer of fibrous substrate 11. The resulting layer 11 is a single integrated layer.

As the layer 11 is formed, it is couched from the cylinder mould cover 24 as a continuous web, for example by a couch roll 30. The couch rcll 30 rotates in contact with the cylinder mould cover 24 and is used to transfer the layer 11 from the cylinder mould cover 24 to a felt 31 (formex) which carries the web from the wet end of the papermaking machine 20 to a press section (not shown in the drawings). Water is extracted from the wet fibrous web and -22 -the web of paper undergoes a drying process. The dried web is initially cut along cutting lines to form a plurality of interim sheets, which are stacked in reams of typically 500 sheets. Preferably the dried security paper 10 has a grammage of between approximately 80 and 200 gsm and more preferably of between approximately 100 and 150 gsm.

When the security paper 10 is required for producing security documents, these interim sheets are typically printed and cut into individual smaller sheets, each of which may form a security document, or a part of a security document, such as a passport, identification card, and the like. The personal data and/cr a machine readable zone are printed onto the first surface 12 of the security paper 10 and the protective layer applied thereover.

Various other embodiments falling within the scope of the present invention will be apparent to the skilled person. An alternative embodiment of the present invention is illustrated in Figure 6. The security paper 40 of this embodiment is multi-layered and comprises first and second layers 41, 42 of fibrous substrate with the security additive 43 located within the first layer 41.

The two-layered security paper 40 may be formed by forming the first layer 41 as described above with reference to Figures 4 and 5. The second layer 42 may be formed by any means known in the art and combined with the first layer 41. For example, as illustrated in Figure 7, a second vat 44 of fibrous stock 45, a second cylinder mould 46 and a felt 47 may be provided for forming the second layer 42 thereon. The felt 47 feeds the second layer 42 into the first layer 41 at -23 -the point where the first layer 41 is couched from the first cylinder mould 21 onto the ccuch roll 30. The first and second layers 41, 42 are thereby combined prior to drying. A similar arrangement may be used to form multi-ply paper in which first and second plies are formed separately, dried and subsequently combined.

An advantage of using two-layered security paper 40 is that the security additive 43 will be further hidden from one side by the second layer 42. Preferably the security additive 43 is embedded within the layer onto which personal data will be printed in the final security document, as it would be this layer that the counterfeiter would seek to reuse after splitting the plies. The second layer 42 can have a lower grammage than the first layer 41 and preferably has a grammage of between approximately 18 and 24 gsm. The first layer 41 preferably has a grammage of between approximately 55 and 180 gsm, and more preferably between approximately 75 and 130 gsm.

It will be appreciated that the security paper 10, 40 may have any suitable number of plies or layers.

Furthermore, although the present disclosure has been particularly directed towards security documents in the form of passports, it will be appreciated that the invention is also applicable to other types of documents of value. In particular, the security document is a banknote, cheque, certificate, passport, passport page, identification card or drivers licence. The personalised information printed thereon may relate to the owner of the security document.

Claims

-24 -CLAIMS: 1. A security paper comprising: at least one layer of fibrous substrate; and a security additive substantially embedded within the fibrous substrate and located within a predetermined region of the at least one layer, at least 75% of the security additive in the predetermined region being fully embedded within the at least one layer, wherein the security additive is detectable when the fibrous substrate is split, thereby 10 exposing the security additive.
2. A security paper as claimed in claim 1 wherein the predetermined region extends through the thickness of the at least one layer.
3. A security paper as claimed in claim 2 wherein the predetermined region extends over the whole of the layer or only partially extends over the layer in a shape or an elongate strip extending from a first edge to an opposing second edge of the security paper.
4. A security paper as claimed in any one of the preceding claims wherein at least 90% cf the security additive in the predetermined region is fully embedded within the layer.
5. A security paper as claimed in any one of the preceding claims wherein the security additive is not substantially detectable at the surfaces of the security paper by a machine.
6. A security paper as claimed in any one of the preceding claims wherein the security additive is not substantially -25 -visible the naked eye when the security paper is viewed in reflected and/or transmitted light.
7. A security paper as claimed in any one of the preceding 5 claims wherein the security additive is substantially hydrophilic or hydrophobic.
8. A security paper as claimed in any one of the preceding claims wherein the security additive is arranged to provide a coloured, metallic, photochromic, iridescent, luminescent, fluorescent, infrared transmitting and/or the like effect.
9. A security paper as claimed in any one of the preceding claims wherein the security additive comprises at least one 15 of a plurality of security fibres, a plurality of security particles, a plurality of planchettes and/or a colourant.
10. A security paper as claimed in claim 9 wherein the length of the security fibres lies in the range 1 to 10 mm, 20 preferably 2 to 7 mm long and more preferably 3 to 5 mm.
11. A security paper as claimed in claim 9 or claim 10 wherein the width of the security fibres lies in the range 20 to 100 pm, and is preferably approximately 50 pm.
12. A security paper as claimed in any one of claims 9 to 11 as dependent on claim 6 wherein the security fibres are dyed, printed upon and/or coated with suitable chemical compositions to provide such effects.

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13. A security paper as claimed in any one of claims 9 to 12 wherein a shape of the planchettes is a symbol, logo or other shape conveying recognisable information.
14. A security paper as claimed in any one of claims 9 to 13 wherein the colourant comprises a dye and/or a pigment.
15. A security paper as claimed in any one of the preceding claims wherein the security paper further comprises at least 10 one further security feature selected from a watermark, an electrotype, print and/or a security thread.
16. A security paper as claimed in any one of the preceding claims comprising a single layer of fibrous substrate.
17. A security paper as claimed in claim 16 wherein the single layer has a grammage cf between approximately 80 and 200 gsm or between approximately 100 and 150 gsm.
18. A security paper as claimed in any one of claims 1 to 15 comprising a first and a seccnd layer of fibrous substrate, the first layer comprising the security additive and having a higher grammage than the second layer.
19. A security document comprising the security paper of any one of claims 1 to 18 wherein the security document is a document of value selected from a banknote, a cheque, a certificate, a passport, a passport page, an identification card and a drivers licence.
20. A security document comprising: the security paper of any one of claims 1 to 18; -27 -personalised data printed on the security paper; and a protective layer provided over the personalised data and attached to the security paper.
21. A security document as claimed in claim 20 wherein the protective layer is a laminate film or a lacquer layer.
22. A security document as claimed in claim 21 or claim 22 wherein the security document is a document of value selected from a banknote, a cheque, a certificate, a passport, a passport page, an identification card and a drivers licence.
23. A method of manufacturing the security paper of any one 15 of claims 1 to 18 comprising the steps of: depositing fibres to form fibrous substrate on a support surface; depositing the security additive on an initial layer of fibres; depositing further fibres over the security additive and the initial layer to form an integral layer of fibrous substrate; couching the layer of fibrous substrate and security additive from the support surface; and drying the layer of fibrous substrate and security additive.
24. A method as claimed in claim 23 wherein the support surface rotates in a vat of fibrous stock, the fibrous stock having an upper surface and the security additive being provided on the initial layer at a predetermined distance below the upper surface.

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25. A method as claimed in claim 24 wherein the initial layer of fibrous substrate is formed at a predetermined distance below the upper surface.
26. A method as claimed in claim 25 wherein the predetermined distance is 50 mm to 1000 mm.
27. A method as claimed in any one of claims 23 to 26 further comprising the step cf combining the layer of fibrous substrate with a second layer of fibrous substrate, said second layer of fibrous substrate being formed in a separate forming step.
28. A security paper as hereinbefore described and with reference to the accompanying drawings.
29. A security document as hereinbefore described and with reference to the accompanying drawings.
30. A method as hereinbefore described and with reference to the accompanying drawings.Amendments to claims have been filed as follows CLAIMS: 1. A security paper comprising: at least one layer of fibrous substrate; and a security additive substantially embedded and dispersed within the fibrous substrate and located within a predetermined region of the at least one layer, at least 75% of the security additive in the predetermined region being fully embedded within the at least one layer, wherein the security additive is detectable when the fibrous substrate is split, thereby exposing the security additive.2. A security paper as claimed in claim 1 wherein the security additive comprises at least one of a plurality of LC) security fibres, a plurality of security particles, a plurality of planchettes and/or a colourant.--3. A security paper as claimed in claim 1 or claim 2 wherein the predetermined region extends through the thickness of --the at least one layer.4. A security paper as claimed in claim 3 wherein the predetermined region extends over the whole of the layer or only partially extends over the layer in a shape or an elongate strip extending from a first edge to an opposing second edge of the security paper.5. A security paper as claimed in any one of the preceding claims wherein at least 90% cf the security additive in the predetermined region is fully embedded within the layer.6. A security paper as claimed in any one of the preceding claims wherein the security additive is substantially not machine readable at the surfaces of the security paper.7. A security paper as claimed in any one of the preceding claims wherein the security additive is not substantially visible the naked eye when the security paper is viewed in reflected and/or transmitted light.8. A security paper as claimed in any one of the preceding claims wherein the security additive is substantially hydrophilic or hydrophobic.Le) 9. A security paper as claimed in any one of the preceding 1--15 claims wherein the security additive is coloured, metallic, 0 photochromic, iridescent, luminescent, fluorescent and/or infrared transmitting. a)10. A security paper as claimed in any one of claims 2 to 9 20 wherein the length of the security fibres lies in the range 1 to 10 mm, preferably 2 to 7 mm long and more preferably 3 to 5 mm.11. A security paper as claimed in any one of claims 2 to 10 25 wherein the width of the security fibres lies in the range 20 to 100 pm, and is preferably approximately 50 pm.12. A security paper as claimed in any one of claims 7 to 11 wherein the security fibres are dyed, printed upon and/or coated with coloured, metallic, photochromic, iridescent, luminescent, fluorescent and/or infrared transmitting chemical compositions.13. A security paper as claimed in any one of claims 7 to 12 wherein a shape of the planchettes is a symbol, logo or other shape which conveys information recognisable to an eye 5 or which is machine readable.14. A security paper as claimed in any one of claims 2 to 13 wherein the colourant comprises a dye and/or a pigment.15. A security paper as claimed in any one of the preceding claims wherein the security paper further comprises at least one further security feature selected from a watermark, an electrotype, print and/or a security thread. 11)1--15 16. A security paper as claimed in any one of the preceding 0 claims comprising a single layer of fibrous substrate.()) 17. A security paper as claimed in claim 16 wherein the single layer has a grammage of between approximately 80 and 200 gsm or between approximately 100 and 150 gsm.18. A security paper as claimed in any one of claims 1 to 15 comprising a first and a seccnd layer of fibrous substrate, the first layer comprising the security additive and having 25 a higher grammage than the second layer.19. A security document comprising the security paper of any one of claims 1 to 18 wherein the security document is a document of value selected from a banknote, a cheque, a certificate, a passport, a passport page, an identification card and a drivers licence.20. A security document comprising: the security paper of any one of claims 1 to 18; personalised data printed on the security paper; and a protective layer provided over the personalised data 5 and attached to the security paper.21. A security document as claimed in claim 20 wherein the protective layer is a laminate film or a lacquer layer.22. A security document as claimed in claim 20 or claim 21 wherein the security document is a document of value selected from a banknote, a cheque, a certificate, a passport, a passport page, an identification card and a LC) drivers licence.23. A method of manufacturing a security paper: depositing fibres to form fibrous substrate on a T support surface; depositing security additive on an initial layer of 20 fibres; depositing further fibres over the security additive and the initial layer to form an integral layer of fibrous substrate, wherein the security additive is substantially embedded and dispersed within the fibrous substrate and is located within a predetermined region of the at least one layer, at least 75% of the security additive in the predetermined region being fully embedded within the layer; couching the layer of fibrous substrate and security additive from the support surface; and drying the layer of fibrous substrate and security additive, wherein the security additive is detectable when the layer of fibrous substrate is split, thereby exposing the security additive.24. A method as claimed in claim 23 wherein the support surface rotates in a vat of fibrous stock, the fibrous stock having an upper surface and the security additive being provided on the initial layer at a predetermined distance below the upper surface.25. A method as claimed in claim 24 wherein the initial layer of fibrous substrate is formed at a predetermined distance below the upper surface.26. A method as claimed in claim 25 wherein the (:) predetermined distance is 50 mm to 1000 mm.()) 27. A method as claimed in any one of claims 23 to 26 further comprising the step cf combining the layer of fibrous substrate with a second layer of fibrous substrate, said second layer of fibrous substrate being formed in a separate forming step.28. A security paper as hereinbefore described and with 25 reference to the accompanying drawings.29. A security document as hereinbefore described and with reference to the accompanying drawings.30. A method as hereinbefore described and with reference to the accompanying drawings.