CN111511572B - Method for surface application of a safety device over a hole made in a paper machine - Google Patents

Abstract

A sheet (110) having a security device (112) applied over a through-hole (111) made or "soft-edged" by a paper machine and a method for making such a sheet (110) are provided. By the method of the invention one or more through-holes are formed in the formed fibrous web before it is sufficiently consolidated, and then a security device is applied to the fibrous web, preferably at or near a couch roll or similar tool of a paper machine over the one or more through-holes when the fibrous web constitutes a sufficiently consolidated, fully formed wet web. Applying the safety device at the papermaking stage where the fibers do not shift and then further consolidating the area under the device greatly reduces, if not eliminates, the possibility of one or more through-holes becoming clogged or blocked. Furthermore, paper made according to the method of the present invention exhibits minimal damage at the paper/security device interface when subjected to flow-through simulation testing. Furthermore, the surface-applied security devices showed acceptable levels of intaglio ink adhesion, and the paper had a higher cross-direction (CD) tensile strength and much less show-through on its opposite sides.

Description

Method for surface application of a safety device over a hole made in a paper machine

technical field

In one aspect, the present invention relates to a sheet material having through holes, wherein one or more safety devices are coupled to the through holes. The sheet material is exemplarily used to form a security document comprising the above-described through-holes and attached security means. In another aspect, the invention generally also relates to a method of making such a sheet; a method of forming security documents; and a device for securing these documents through the coupling of through holes to one or more security devices. Vias as described herein include "soft edge" vias. Accordingly, another aspect of the present invention also includes a method of forming soft edged through holes in a sheet material or, more specifically, a security document.

Background technique

Security devices including, non-exclusively, various forms of strips, tapes, threads or ribbons are widely used to protect or aesthetically high security and high value documents, thereby providing visual and/or machine accessibility for verifying the authenticity of these documents. testing method. These security devices can be fully or partially embedded in the document, or mounted on its surface.

The at least partially embedded safety device may be applied to the forming fibrous web by introducing the safety device into the fibrous web during the wet stage of the papermaking process. However, the introduction of security devices into the fibrous web at this stage, while suitable for embedded and partially embedded security devices, has hitherto been impractical for surface-applied security devices as the resulting sheet or document would be prone to lowering Durability (eg, circulation durability).

It has been found that some fibers are displaced as they flow around the safety device as the safety device is pressed into the fibrous web during the wet stage of its introduction into the forming fibrous web. This results in a certain amount of fibre being displaced from the sub-areas (ie the area of the fibrous web that is located under or below the safety device) and the hinge area (ie the area of the fibrous web that is located adjacent to the edge or side of the safety device), so The displacement is sufficient to affect the interaction of the security device with the fibrous web or with the substrate of the resulting sheet or document. The resulting fiber concentration in the sub-regions and hinge region is less than the fiber concentration in at least the adjacent one or more bulk regions. This results in weak tie interactions at the interface of the security device and the substrate of the sheet or document, and in particular at the interface surfaces and/or edges of the security device. During use or circulation of the resulting document, these weak areas are very susceptible to tearing in the sheet or document along the interface edges between the security device and the substrate, or to create a hinge effect (ie, areas of separation between the interface edges). Furthermore, the document tends to exhibit backside print-through; that is, when applied on one side of a fibrous web, the applied security device will produce a document that can be obtained from the fibrous web, any resulting fibrous sheet, or any resulting document The shadow effect observed on the opposite side of the . This usually requires the use of a backside camouflage coating to solve the problem. It has also been observed that the resulting sheet or document exhibits a reduction in cross direction (CD) tensile strength.

An alternative for obtaining a surface-applied safety device is to apply the safety device to the surface of a fully formed fiber substrate. However, application to fully formed fibrous substrates comes with other substantial limitations. For example, this substantially limits the range of thicknesses of safety devices that can be used. Typically, surface application is limited to the thinnest (such as less than 15 micrometers (μm)) security devices. Thicker safety devices are generally excluded from such applications, at least in part, because the resulting difference in thickness on the resulting sheet affects downstream processing. As used herein, the term "thickness difference" refers to the difference in height measured from the upper surface of the body region of the sheet to the upper surface of the safety device. Therefore, the thickness difference can be negative or positive. For example, where the upper surface of the safety device is located below the height of the upper surface of the main body region of the sheet, the thickness difference is negative. Conversely, where the upper surface of the safety device is located above the height of the upper surface of the body region of the sheet, the difference in thickness is positive. Alternatively, a thickness difference of zero indicates that the upper surface of the safety device is flush with the upper surface of the body region. Downstream processes such as winding, sheeting, stacking, cutting and processing by ATM suffer in terms of time and cost due to thickness differences created by thicker safety devices introduced during the drying stage of the papermaking process or during post-application. Importantly, the stacks produced in this way are not ready for pressing or printing.

In view of the foregoing, there remains a need for improved sheets with surface-applied safety devices, regardless of thickness, and for improved methods of producing these sheets. There is also a continuing need to provide secure documents with additional authenticity features that allow verification of document authenticity while preventing unauthorized copying.

SUMMARY OF THE INVENTION

The present invention addresses at least one of the above needs by providing a sheet, a security document, and a method for surface application of a security device to a fibrous sheet or document by introducing the security device into a forming fibrous web during the wet stage of papermaking . In one embodiment, the safety device is applied over one or more "soft edge" through-holes formed in the fibrous web. The safety device in this embodiment is fabricated from a structural film and has a thickness of at least about 10 microns to provide sufficient durability for the device across one or more through holes. As used herein, the term "soft edged through-holes" means through-holes created during papermaking by fibers in a sheet extending into openings surrounded by through-holes. The openings of the through holes extend from one side or surface of the web to the opposite side or surface and exhibit unique irregularities in the edge regions. This unique irregularity is caused by the lack of sharp cutting edges and includes irregular accumulation of fibers in the edge region and/or fibers extending into the openings. Where such through openings have unique irregularities that vary frequently and are not easily replicated, these openings serve as authenticity features with a high security value. The method of the present invention comprises introducing a safety device onto or into the formed fibrous web, optionally during the wet stage of the papermaking process in which the fibrous web is sufficiently consolidated, optionally in one or more of the formed fibrous webs. above a "soft edge" via. In one embodiment, a fibrous web is sufficiently consolidated when the fibrous web has a water or moisture content of less than 98% by weight based on the total weight of the fibrous web. Preferably, the fibrous web is sufficiently consolidated when it is at or near the couch roll or similar tool of the paper machine.

The present invention also provides the fibrous sheet produced by the above method and the resulting document comprising the fibrous sheet. In a first embodiment, a fibrous sheet has: opposing surfaces; at least one recess on one surface thereof; a fiber sub-region, which is a three-dimensional volume disposed under or below the recess; and a fiber body region, The fiber body region is also a three-dimensional volume disposed adjacent to the recesses and sub-regions; a surface-applied safety device disposed in the recesses; and the interface between the surface-applied safety device and the body region and sub-regions of the sheet; wherein in the fiber sub-region The fibers are present in substantially equal amounts in the fiber body region. The fiber sub-regions are coextensive with the surface-applied safety device in the transverse or lateral direction. In other words, the three-dimensional sub-regions occupy the volume of the fiber sheet below the safety device. The fiber body regions are positioned adjacent the recesses and subregions and occupy the remaining volume of the fiber sheet.

By comparing the mass (weight) of the three-dimensional area of the sheet under the safety device (after the safety device has been removed (see eg the area defined by the width A, height a and depth dimensions (not shown) in Figure 11) A three-dimensional area of equal width (ie, width equal to the width of the safety device) of the sheet adjacent to the safety device (see, eg, the area defined by the width B, height b, and depth dimensions (not shown) in FIG. 11 ) ) to achieve confirmation of the presence of substantially equal amounts of fibers in both the sub-regions and the bulk region of the sheet. In the following descriptions where through-holes are present in the region of the sheet below the safety device In an embodiment, the mass (weight) in the region now occupied by the via is first adjusted by adding back the mass (weight) of the region, and then the mass (weight) of the region (sub-region) is compared to the mass (weight) of the main region ( weight) for comparison.

In a second embodiment or aspect of the present invention, the fibrous sheet has opposing surfaces and one or more paper machine made or "soft edged" through holes. A surface-applied safety device is applied over the one or more through-holes, the surface-applied safety device may be substantially the same or different in shape and size than the one or more through-holes. For example, a surface-applied safety device may be shaped differently and larger than the through-hole, or it may be sized to be similar to and only slightly larger than the through-hole. In both cases, the fibrous sheet and the document formed therefrom will be similar to that described above, except that one or more through holes will extend from the recesses through opposing surfaces of the fibrous sheet. Fiber sub-regions with a three-dimensional volume will therefore be positioned below or below those recessed regions that define the through-holes, and extend laterally therefrom to the outer perimeter of the surface-applied safety device. In other words, as described above, the fiber sub-regions will occupy space below the space occupied by the surface-applied safety device.

Surprisingly, it has been found that a surface-applied safety device can be introduced during the wet stage when the fibrous web is sufficiently consolidated into eg a fully formed wet web. By introducing the safety device during this wet stage of the papermaking process, the safety device can be pushed sufficiently into the fibrous web to further consolidate the fibers in the sub-regions rather than dislodging them. This in turn helps to provide increased connection interaction between the fibers and the surface applied safety device. As a result, at least one of durability, ink adhesion, cross direction (CD) tensile strength, and backside print-through is improved. These surprising advantages obviate the need for further processing steps to improve ink adhesion, improve tensile strength, or camouflage backside print-through. Furthermore, since the safety devices are introduced during the wet phase when the fibrous web is sufficiently consolidated, it is made possible to force the safety devices into the fibrous web, enabling the use of thicker safety devices as their thickness difference can be significantly reduced. The resulting thickness difference has less impact on downstream processes.

Through the methods provided herein, Applicants have also surprisingly discovered that a surface-applied security device can be applied in registration with at least one other feature in the fibrous web, fibrous sheet, or resultant document. In a second aspect of the invention, the surface-applied safety device is applied in registration with the one or more through holes. As those skilled in the art will readily appreciate, the application of the security device in registration with a further feature in the fibrous web greatly increases the security of the resulting sheet or document. Furthermore, since safety devices are introduced during the wet stage of the fiber web manufacturing process, it is possible to adjust the registration during the papermaking process. Thus, further processing steps that would otherwise be required to correct misalignment of the safety device with other features are avoided. Introducing the safety device in a continuous manner also avoids the need for a carrier substrate since the safety device can be cut/punched and introduced into the fibrous web with a single introduction device. As used herein, the term "introduction device" refers to a device for cutting/punching and/or introducing a safety device into the fibrous web during the wet stage. Suitable introduction devices are described further herein.

Other features and advantages of the present invention will be apparent to those of ordinary skill in the art from the following detailed description and accompanying drawings. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. Furthermore, the materials, methods, and examples are illustrative only and not intended to be limiting. Furthermore, all ranges expressly recited herein also implicitly encompass all subranges.

Description of drawings

The present disclosure may be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Although exemplary embodiments are disclosed in connection with the accompanying drawings, it is not intended to limit the disclosure to the embodiment or embodiments disclosed herein. On the contrary, the intention is to cover all alternatives, modifications and equivalents.

Certain features of the disclosed invention are illustrated with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional side view of a fibrous sheet produced by introducing a safety device into a fibrous web during the wet stage of papermaking without adequate consolidation of the fibrous web;

Figure 2 is a fibrous sheet produced by introducing a safety device onto a fibrous web during or after the drying stage of papermaking when the moisture content is too low to allow the safety device to be pressed into the substrate to further consolidate the fibers cross-sectional side view;

3 is a cross-sectional side view of an exemplary embodiment of a fibrous sheet of the present invention having a surface-applied safety device, wherein the safety device is introduced into the fibrous web when the fibrous web is sufficiently consolidated or above;

Figure 4 is a schematic diagram of a Fourdrinier wire machine in which a safety device in the form of a continuous web is introduced into the forming fibrous web on the wire after the wet line and before the couch roll;

5 is a top view of an exemplary embodiment of a document having a plurality of discrete surface-applied security devices (patches and strips) applied thereon in accordance with the present invention;

6 is a top view of another exemplary embodiment of a document having a plurality of discrete surface-applied security devices (patches) applied in registration with another feature in the document, such as a watermark, in accordance with the present invention;

Figure 7A is of a fibrous sheet or document after it has been subjected to one (1) cycle through a flow-through simulation test, produced by introducing a safety device into a forming fibrous web when the fibrous web is not sufficiently consolidated during the wet stage of papermaking front plan;

Figure 7B is the back side of a fibrous sheet or document after it has been subjected to one (1) cycle through the flow-through simulation test, produced by introducing a safety device into the fibrous web when the fibrous web is not sufficiently consolidated during the wet stage of papermaking the floor plan;

Figure 8A is a fibrous sheet produced by introducing a safety device into a forming fibrous web when the fibrous web is sufficiently consolidated during the wet stage of papermaking in accordance with the present invention after it has been subjected to one (1) cycle through a flow-through simulation test or a plan view of the front of an exemplary embodiment of the document;

Figure 8B is a fibrous sheet after having been subjected to one (1) cycle through a flow-through simulation test produced by introducing a safety device into a fibrous web when the fibrous web is sufficiently consolidated during the wet stage of papermaking, or A plan view of the back of the exemplary embodiment of the document;

Figure 9A is the front side of a fibrous sheet or document after it has been subjected to three (3) cycles through the flow-through simulation test, produced by introducing a safety device into the forming fibrous web when the fibrous web is not sufficiently consolidated during the wet stage of papermaking the floor plan;

Figure 9B is a fibrous sheet or document after it has been subjected to three (3) cycles through the flow-through simulation test, produced by introducing a safety device into the forming fibrous web when the fibrous web is not sufficiently consolidated during the wet stage of papermaking plan view of the back;

Figure 10A is a fibrous sheet after having been subjected to three (3) cycles through a flow-through simulation test or a a plan view of the front of the exemplary embodiment of the document;

Figure 10B is a fibrous sheet after having been subjected to three (3) cycles through a flow-through simulation test or a A plan view of the back of the exemplary embodiment of the document;

Figure 11 is another exemplary embodiment of a fibrous sheet of the present invention (second aspect) produced by incorporating a safety device into a fibrous web having opposing surfaces and paper machine made or "soft edge" through holes cross-sectional side view. introducing a safety device into or on the fibrous web once the fibrous web is sufficiently consolidated; and

Figure 12 is a schematic diagram of a Fourdrinier wire machine in which a patterned forming wire is used to introduce through holes in a forming fibrous web and then a safety device in the form of a continuous web is introduced into the fibrous web after the wet line and before the couch roll. The patterned forming wire is depicted in Figure 12A prior to discharging the papermaking stock from the headbox onto the forming wire, while the same forming wire after discharging the papermaking stock onto the wire is depicted in Figure 12B.

Detailed ways

The invention will be further understood through the following details, which are provided as a description of certain exemplary embodiments of the claimed invention.

By the method of the present invention, a fibrous sheet including a surface-applied safety device is provided. In a first aspect of the present invention, a method for surface application of a safety device to a fibrous sheet is provided. The method includes introducing a safety device into or onto the fibrous web during papermaking. In a second aspect, the method comprises forming one or more "soft edge" through-holes in the fibrous web during papermaking before the fibrous web becomes sufficiently consolidated, and then once the fibrous web has become sufficiently consolidated, The safety device is then introduced into or on the fibrous web over one or more "soft edge" through holes. By forming the through-holes during papermaking, the through-holes are thus provided with unique edge irregularities that serve as authenticity features with a high security value. Furthermore, by introducing safety devices during the papermaking process, the known processing steps are uninterrupted and additional processing steps are eliminated. Furthermore, by introducing the safety features during the wet stage of the papermaking process, thicker safety features can thereby be applied than those that can be applied during the dry stage of the papermaking process.

In one embodiment, the method further comprises further consolidating the fibers in the sub-regions. To further consolidate the fibers in the sub-regions, a surface-applied safety device is pressed into the fully consolidated (uniform or non-uniform) fibrous web. The fibers are compacted in this region such that despite the reduced volume of the subregion, the amount of fibers in this region is not displaced; at least not by any significant amount. The fact that the fibers in this region are not displaced greatly reduces, if not eliminates, the likelihood that one or more of the through holes will become blocked or blocked as the fibers consolidate further in this region.

As used herein, with respect to this disclosure, one of ordinary skill in the art will understand that the term "substantially consolidated" means that the fibrous web is in a fully formed wet web state. In this wet web stage, the fibrous web contains less than 98% water and/or moisture. Thus, the fibrous web contains more than 2% fibers and/or pulp. In another embodiment, the fibrous web comprises less than 95% water and/or moisture, with the remaining 5% of the constituents being fibers and/or pulp. In more preferred embodiments, the water and/or moisture in the fibrous web is in the range of about 60% to less than 98%, or about 60% to about 95%. Applicants have found that water and/or moisture levels above 98% cause fibre displacement when the safety device is introduced. Significant displacement of fibers, especially in sub-regions of the substrate, results in weak interactions between the safety device and fibers in the substrate. In particular, the displacement of the fibers reduces the durability and strength of the substrate and reduces the camouflage effect provided in the sub-regions and hinge regions. As described herein, these weak interactions, especially at the interface edges of the safety device, lead to the problems identified above. Accordingly, it has also been found that where the fibrous web has less than 60% water and/or moisture, the introduction of the safety device during the papermaking process is not sufficient to allow the safety device to be recessed to accommodate thicker safety devices while still maintaining Low thickness difference. Furthermore, at less than 60% water and/or moisture, the fibers in the sub-regions cannot consolidate further enough to secure the fibers near the interface edge of the safety device. As used herein, the term "recessed" refers to pressing the safety device into the fibrous web to form a relief/recess in the base surface of the fibrous sheet such that at least a portion of the height of the safety device is recessed into the surface of the body area height, while the top or upper surface area of the safety device remains exposed.

The wet stage as defined above can be adjusted to various positions along the paper machine, and the present invention contemplates all these possibilities. However, in preferred embodiments, during the wet stage of the papermaking process, such as at or near a couch roll or similar tool in a paper machine, when the fibrous web constitutes a fully consolidated or fully formed wet web (ie, has a The total weight of the fibrous web is less than 98% by weight of the fibrous web, preferably from about 60% to less than 98% by weight of the fibrous web, or more preferably from about 60% to about 95% by weight of the fibrous web, or from about 60% to about 90% moisture or water content by weight of the material), the safety device is applied in or on the forming fibrous web. In such locations, no further process adjustments are required to accommodate the integration of the safety device into the recess. For example, a suction box is usually located directly in front of the couch rolls to remove as much moisture as possible before the web leaves the wet end of the machine in order to minimize the burden on the dryer section of the machine. Similarly, the fibrous web will preferably be comprised of from about 75% to about 95% water and/or moisture and from about 5% to about 25% on exiting the cylinder section of the rotary wire machine (and after the couch roll) of pulp or fibers.

While it is envisaged to provide adequate consolidation of the fibrous web (as defined herein) at several papermaking stages on a Fourdrinier wire machine, in a preferred embodiment the safety device is introduced into the fibrous web during the papermaking stage immediately following the wet After the line and before the couch. This is the point at which there is no longer significant surface water on the upper side of the fibrous web. In an alternative embodiment, the safety device is introduced into the fibrous web on or before the vacuum box in the wet end, which advantageously aids in the placement of the device into the web. Preferably, the safety device is placed directly to the face of the fibrous web via transfer wheels, rollers or contact shoes.

In one embodiment, while moving past or further past the couch roll, the fibrous web is in a state of a fully formed web with surface-applied safety devices as it travels to the dry end of the paper machine, which is formed by the press section and dryer section.

In the press section of both types of paper machines, water and/or moisture is removed by compressing the wet paper between rolls and felt to reduce the water and/or moisture content to a desired level. Applicants have surprisingly found that compressing a fully formed wet web with surface-applied safety devices results in further consolidation of the fibers in sub-regions (ie the regions of the fibrous web below or below the introduced safety devices), Because they are compacted and not displaced. As a result, the strength properties of the resulting fibrous sheet or resulting document are improved as well as the backside opacity which provides camouflage of the security device to reduce backside print-through.

The safety device of the present invention can have various thicknesses. However, it has been found that the method of the present invention advantageously allows for the surface application of safety devices on the thicker end of the thickness spectrum. In one embodiment, the security device has a thickness of up to 100 micrometers (μm). In another embodiment, the safety device has a thickness in the range of 5 μm to 75 μm or more preferably 10 μm to 50 μm. The width of the safety device is limited only by the width of the fiber sheet. In a preferred embodiment, the width is in the range of 0.25 millimeters to 20 millimeters (mm), more preferably 0.5 mm to 15 mm.

By introducing safety devices during the wet stage of papermaking, these safety devices can be pressed into the fibrous web to create recesses in the surface of the resulting fibrous sheet. The resulting fibrous sheet comprises a surface-applied safety device with a thickness difference that does not lead to the above-mentioned disadvantages. In one embodiment, the difference in thickness is expressed relative to the thickness of the safety device. In this embodiment, the absolute value of the difference in thickness is in the range of 0% to about 80% of the thickness of the safety device; preferably less than 10% of the thickness of the safety device.

In one embodiment, the difference in thickness is in the range of -10 μm to about 50 μm. More preferably, the thickness difference is in the range of -5 μm to 30 μm, or 0 μm to 25 μm.

In certain embodiments, the device is thin enough that the indentation of the safety device into the fibrous wet web results in a negative caliper difference (ie, the thickness or height of the safety device is less than the thickness or height of the body region). In such embodiments, the difference in thickness is best characterized by reference to the absolute value of the difference in thickness relative to the thickness of the safety device. For example, in one embodiment, the thickness of the safety device is less than 25 μm such that when the safety device is pressed into the fibrous web, the absolute value of the difference in thickness of the surface-applied safety device is between 0% and about 50% of the safety device thickness. %, more preferably from 0% to about 30%, even more preferably from about 0% to about 10%. In a further embodiment, the thickness of the safety device is likewise less than 25 μm, such that further consolidation of the sub-regions by pressing the safety device into the fibrous web results in a thickness in the range of -10 μm to 15 μm, preferably -5 μm to 10 μm Difference.

Alternatively, in one embodiment, the thickness of the safety device is greater than 25 μm, such that further consolidation of the sub-regions by pressing the safety device into the fibrous web results in a range between -10 μm and 50 μm, preferably between -5 μm and 25 μm, or thickness difference in the range of 0 μm to 15 μm. In one other embodiment in which the safety device also has a thickness greater than 25 μm, the difference in thickness is in the range of 0% to about 50% relative to the absolute value of the safety device thickness. Preferably, the absolute value of the thickness difference is in the range of 0% to about 20% of the thickness of the safety device.

A "couch roll" will be understood by those of ordinary skill in the art as a guide roll for a Fourdrinier wire on a Fourdrinier wire machine positioned at the point where the web leaves the wire (ie, the wet end or paper forming section) and the wire returns to the breast roll or steering rollers. Couch rolls are used for the same purpose on rotary wire machines, where the Fourdrinier wire section has been replaced by the rotary wire section. Specifically, the couch rolls guide and turn the web as it leaves the cylinder section and travels towards the couch rolls.

While it is also contemplated that the entire fibrous web has a uniform consistency in water and/or moisture content and fiber content, it is also within the scope of the present invention that the fibrous web is not uniformly sufficiently consolidated. For example, in one embodiment, the fibrous web is sufficiently consolidated only at or along the point of introduction. As used herein, "entry point" refers to an area at or along a fibrous web that is at least partially covered by a safety device. In another embodiment, the fibrous web is only partially sufficiently consolidated or sufficiently consolidated in a gradient or matrix pattern such that at the point of introduction, the fibers are not significantly dispersed to cause the identified disadvantage. For example, by selective vacuum treatment at locations along the forming fibrous web, a well consolidated gradient or matrix pattern can be provided. Alternatively, in one embodiment, the moisture content is removed in a gradient or matrix pattern by applying a radiation source (ie, heat) to remove top surface water at selected locations along the forming fibrous web.

The introduction of the security device into the fibrous web forms an interface between the security device and the base fibrous web, the resulting fibrous sheet, or the resulting document. As used herein, the term "interface" may be formed by direct or indirect contact between the security device and the substrate. Where the interface is direct, the safety device is in direct contact with the fibers in the substrate. However, it is contemplated that the safety device forms an indirect interface with the substrate along some or all of the bottom and side surfaces. For example, the interface may include other materials between the security device and the substrate. Although various materials are contemplated, additional fibers or polymeric materials (eg, monocomponent and/or multicomponent fibers, either alone or in combination, obtained from natural sources such as plant sources or spun from polymer melt compositions, etc.) is particularly suitable. Furthermore, a binder material is preferred for forming the indirect interface. The activatable adhesive can be used to anchor or bond the safety device onto or into the concave surface of the fibrous web. Suitable adhesives are not limited and include, but are not limited to, water activated, heat activated and/or pressure activated adhesives activated in the dryer section of the paper machine where the temperature reaches 100°C to 160°C. These coatings can be applied in the form of solvent-based polymer solutions or aqueous solutions or dispersions. Suitable dispersions are selected from the group consisting of acrylic resin dispersions, epoxy resin dispersions, natural latex dispersions, polyurethane resin dispersions, polyvinyl acetate resin dispersions, polyvinyl alcohol resin dispersions, urea-formaldehyde resin dispersions, vinyl acetate Ester resin dispersions, ethylene vinyl acetate resin dispersions, ethylene vinyl alcohol resin dispersions, polyester resin dispersions, and mixtures thereof. While moving past the couch roll, the fully formed wet web with surface-applied safety devices travels to the dry end of the paper machine, which consists of a press section and a dryer section. The adhesive may alternatively form part of the safety device, and in such embodiments has a thickness in the range of 5 μm to about 50 μm, preferably 5 μm to about 20 μm.

Security devices suitable for use in the present invention include those commonly used by those of ordinary skill in the art to provide security against counterfeiting or counterfeiting. In a second aspect of the invention, the safety device is preferably formed from a structural film (eg, polyethylene terephthalate (PET) film) and has a thickness of at least about 10 to 15 microns, which provides the device with Sufficient durability to allow it to span one or more vias. As used herein, the term "structural film" is intended to mean a film with structural integrity that is an integral part of the structure of the security device, rather than, for example, a removable carrier film commonly used with transfer foils, or the transfer foil itself. The security devices may be those adapted to alternatively or additionally apply aesthetic features to the substrate. A suitable security device may display information that is perceptible to humans, either directly or with the aid of the device, or may additionally or alternatively display information that is perceptible to machines. The security device may employ one or more of the following features: de- or selectively metallized, magnetic, combined magnetic and metallic, or embossed areas or layers, by color shifting, iridescence, liquid crystal, light Color-changing coatings of photochromic and/or thermochromic materials, coatings of luminescent and/or magnetic materials, holographic and/or diffractive security features, and micro-optical security features. In a preferred embodiment, the security device provides security so that the security or document of value can be easily authenticated. In one embodiment, the security device includes an array of focusing elements and an array of image icons, wherein the array of focusing elements and image icons are arranged such that one or more composite images are projected by the security device. Focusing elements used in the present invention are used to highlight, magnify, illuminate, or accentuate small points in an array of image icons, and include, but are not limited to, lenticular lenses and acylindrical lenses (ie, microlenses). Composite imaging, mentioned above, is a form of ensemble imaging in that the image perceived by the observer is composited from hundreds or thousands of individual image segments that are magnified by a lens (eg, a microlens) and directed toward The observer's eye projection.

In an exemplary embodiment, the security device is a microlens based security device. Such devices typically include (a) a light transmissive polymer substrate, (b) an arrangement of micro-sized image icons on or within the polymer substrate, and (c) an arrangement of focusing elements (eg, microlenses). The image icons and focusing element arrangement are configured such that one or more composite images are projected when the arrangement of image icons is viewed through the focusing element arrangement. These projected images can display many different optical effects. Material constructions capable of exhibiting such effects are described in US Patent No. 7,333,268 to Steenblik et al., US Patent No. 7,468,842 to Steenblik et al., US Patent No. 7,738,175 to Steenblik et al., US Patent No. 7,738,175 to Commander Patent No. 7,830,627, US Patent No. 8,149,511 to Kaule et al; US Patent No. 8,878,844 to Kaule et al; US Patent No. 8,786,521 to Kaule et al; European Patent No. 2162294 to Kaule et al; Application No. 08759342.2 (or European Publication No. 2164713). These references are incorporated herein in their entirety.

In preferred embodiments, surface-applied security devices by the methods of the present invention include, but are not limited to, micro-optical security devices (such as the MOTION ^™ micro-optical security device described, for example, in US Pat. No. 7,333,268), RAPID ^™ , Holographic security devices (eg metallized holographic devices). These devices are available from Crane Currency US, LLC of Massachusetts, USA. Other suitable devices include, but are not limited to, optically variable devices (OVDs) such as KINEGRAM ^™ optical data carriers and color shift security devices.

Although the safety device can be present in various forms to be introduced into the fibrous web, it has been found to be most advantageous to provide the safety device in the form of a continuous web. By providing the safety device in the form of a continuous web, it has been found that the safety device can be introduced into the fibrous web in a continuous manner. The continuous web is then segmented or divided into multiple discrete safety devices. Segmenting the continuous web into discrete safety devices can be accomplished by various cutting and/or punching methods. In a preferred embodiment, the method is a process of applying a plurality of discrete safety devices in series to the fibrous web without the use of a carrier film during manufacture on a paper machine. The method includes providing a safety device in the form of a continuous web; cutting or punching the continuous web in a continuous manner to form discrete safety devices, each safety device having a desired shape and size; and then in a continuous fashion during papermaking Discontinuous safety devices are applied to the fibrous web.

It is contemplated herein that additional safety devices may be applied to the fibrous sheet by surface application, partial embedding or full embedding. For example, in one embodiment, additional safety features are applied to the surface of the fiber sheet. The additional means may be introduced into the fibrous web prior to introduction of the surface-applied safety means, or applied after the introduction of the surface-applied safety means. This additional safety device may be different or similar to the surface-applied safety device. For example, in one embodiment, when one of the discrete safety devices has a thickness of 25 μm or less, it is envisaged when the moisture content is less than 60% by weight, preferably in the range of about 90% to 0% It is introduced into the fibrous web. For example, a safety device is introduced into the fibrous web as it travels through the paper machine between the first dryer section and the size press, and is optionally rewetted to increase the water and/or moisture content to Between about 4% and about 7%.

Safety devices come in a variety of sizes, shapes or colors. For example, it is envisaged that a safety device in the form of a discontinuous safety device takes the non-limiting form of a strip, tape, thread, ribbon or patch. These devices may have an overall width of about 2 mm to about 25 mm (preferably, about 6 mm to about 12 mm), and an overall thickness of about 10 microns to about 50 microns (preferably, about 20 microns to about 40 microns). In a preferred embodiment, the safety device is a strip or patch. As used herein, "strip" refers to a security device having a longitudinal length dimension that is substantially greater than a transverse width dimension. In contrast, a "patch" may have substantially equal longitudinal and transverse lengths, and may have uniform or various non-uniform shapes. This article contemplates strips and patches of various shapes and sizes. However, while the strips or patches may extend to the edges of the fibrous sheet or the resulting document, in preferred embodiments the strips or patches are located within the perimeter of the fibrous sheet or document and do not extend to the edge of the sheet or document. edge.

As mentioned, various sizes of safety devices are considered suitable for the method and fiber sheet of the present invention. In one embodiment, the dimensions have an overall length in the range of about 5 mm to about 75 mm, preferably about 15 mm to about 40 mm; and an overall width of about 2 mm to about 50 mm, preferably about 6 mm to about 25 mm; and an overall thickness From about 10 microns to about 50 microns, preferably from about 15 microns to about 40 microns. All ranges mentioned herein include all subranges, including integers and fractions. As noted above, in the second aspect of the invention, the security device is preferably formed from a structural film (eg, polyethylene terephthalate (PET) film) and has a thickness of at least about 10 to 15 microns , which provides the device with sufficient durability to allow it to span one or more vias.

As mentioned, various shapes of security devices are also contemplated; eg patches, strips or lines, geometric shapes (such as star, parallelogram, polygonal (eg hexagon, octagon, etc.) shapes), numbers, letters and various symbols. Simple and complex non-geometric designs are also considered suitable. These shapes and designs can be cut through a rotary die process.

In one embodiment of the method of the present invention, the security device is incorporated into the forming fibrous web such that it registers with at least one other feature on or in the substrate of the fibrous web, fibrous sheet or resultant document. In certain embodiments, a security device is introduced such that a particular feature within the security device registers with another feature in the fibrous web, resulting fibrous sheet, or document. The at least one other characteristic may vary as desired with respect to the application. For example, the at least one other feature is a watermark, a printed image, an embossed structure, another security device or a paper feature. In a second aspect of the invention, the safety device is introduced such that it preferably registers with one or more "soft edge" through holes. When introducing a safety device into a fibrous web so that it is in registration, it is envisaged to first deliver the safety device in the form of a continuous web to a piece of equipment or system (referred to herein as an introduction device) that can be used to introduce the continuous web Wood cutting/punching into discrete safety devices. Although it is possible to use a separate device to cut and then apply the safety device to the fibrous web, it is preferred that the system for forming the discontinuous safety device is also used to apply the safety device into or onto the fibrous web. With a single device, it is possible to apply the safety device in more precise registration as it requires fewer moving parts.

In a preferred embodiment where the continuous web is cut into discrete safety devices which are then introduced into or onto the fibrous web by the same introduction device, it is also envisaged that the placement of the safety devices can be performed by the introduction device The adjustment is such that the unregistered (unregistered with at least one other feature) security device can be adjusted into registration in a continuous manner. By using a single introduction device to cut, apply and adjust the registration in situ during the papermaking process, no additional processing is required to adjust the placement. For example, application and adjustment in registration during the papermaking process eliminates the need for secondary processing of the resulting sheet or document prior to printing.

Appropriate introduction means will be apparent to those of ordinary skill in the art after an understanding of the present disclosure. However, in a preferred embodiment, the introduction device is a system employing an optical or fiber density sensor that checks the registration between the security device and at least one other feature in the fibrous web, fibrous material, or resultant document. In view of the identified or calculated position of the safety device or the relative position of the safety device to the at least one other feature, the lead-in device is used to make adjustments in the placement of the safety device. To make such adjustments, the introduction device uses a variable speed advance (eg, an electric servo with a servo drive) that controls the tension on the continuous web so that the discontinuous safety device can be applied in registration as needed. Thus, the point of introduction of the safety device is continuously adjusted by adjusting the tension on the continuous web. Alternatively, the introduction device may be a rotary die cutting and transfer device, such as is used in the label industry to apply labels in registration.

In a second aspect of the present invention there is provided a method for forming one or more "soft edge" through holes in a forming fibrous web and then surface applying a safety device over the one or more through holes . In this second aspect, the method includes forming one or more "soft edge" through-holes in the forming fibrous web during papermaking, and once the fibrous web is sufficiently consolidated (uniformly or non-uniformly), Safety devices are introduced into or on the forming fibrous web over one or more "soft edge" through holes.

Although the second aspect of the invention is described as having the safety device over the one or more through holes, the safety device and the one or more through holes may be otherwise registered or not registered at all. For example, the safety device and the one or more through-holes may be registered in a side-by-side configuration, wherein the safety device is positioned on/in the fibrous web adjacent the one or more through-holes.

In one embodiment of the method of the present invention, the method further comprises further consolidating the fibers in the sub-regions of the fibrous sheet. To further consolidate the fibers in the sub-regions, surface-applied safety devices are pressed into the fully consolidated fiber web. The fibers are compacted in this area so that despite the reduced volume of the sub-areas, the amount of fibers in this area (around the one or more through holes) is not displaced, at least not by any significant amount. As noted above, the fact that the fibers in this region are not displaced greatly reduces, if not eliminates, the likelihood that one or more of the through holes will become blocked or blocked as the fibers in the region further consolidate.

One or more through holes are created before the forming fibrous web becomes "well consolidated" during the wet web stage of papermaking. In other words, the fibrous web is not in a fully formed wet web state. Thus, the fibrous web comprises water and/or moisture content above 98% by weight of the fibrous web. In order to be able to create this through-opening, the screen of the paper machine must be provided with at least one water-tight element, which prevents sheet formation in this area. The papermaking screen can be a continuously moving forming wire of a Fourdrinier wire machine or a cylinder wire of a rotary wire machine.

The through holes may take any suitable size and shape or profile. For example, the vias may be circular, oval, star-shaped, formed to resemble a parallelogram (eg, square, rectangle) or trapezoid, and the like. In an exemplary embodiment, the aperture has at least one intersecting dimension that is about 1 millimeter (mm) narrower/smaller than the safety device placed over it. The intersection dimension refers to the line between two points on the aperture that intersect at at least a portion of the safety device. Therefore, if the diameter of the hole is 5mm, the device will have to have a minimum dimension of at least about 6mm. If the hole is irregular (eg star shaped), the narrowest edge of the device must be about 1 mm from the widest edge of the hole. The shape or profile of the one or more through holes may match or coordinate with the shape or profile of the security device and/or the image displayed or projected by the security device.

After the one or more through holes are formed and the fiber web is sufficiently consolidated, a safety device is applied over the one or more through holes. As noted above, in preferred embodiments, during the wet stage of the papermaking process, such as at or near a couch roll or similar tool in a paper machine, when the fibrous web constitutes a fully consolidated or fully formed wet web (ie, having less than 98% by weight of the fibrous web, preferably from about 60% to less than 98% by weight of the fibrous web, or more preferably from about 60% to about 95% by weight of the fibrous web, based on the total weight of the fibrous web, or 60% to about 90% moisture or water content by weight of the fibrous web), the safety device is applied in or on the forming fibrous web.

The surface-applied safety device can be shaped the same as or different from the one or more through holes, and can be sized much larger than the one or more through holes or only slightly larger than the one or more through holes. As noted above, the safety device may take the non-limiting form of strips, strips, wires, ribbons or patches, while the through holes may be circular, oval, star-shaped, formed to resemble a parallelogram (eg, square/rectangular) or trapezoid etc. In an exemplary embodiment, the surface-applied safety device is extending along all or part of the entire length or width of the fibrous sheet made from the fibrous web having a range of between about 5 mm and about 20 mm (preferably between about 8 mm and 20 mm). Slender safety wire with a width in the range of about 12mm). In another exemplary embodiment, the through hole has a circular shape with a maximum diameter ranging between 5mm to 15mm (preferably about 7mm to about 10mm) and the surface applied safety device is of complementary or contrasting shape and A patch with a width and length that is at least 2mm larger than the hole.

In another aspect of the present invention, a fibrous sheet is provided. The fibrous sheet as described herein is the result of further processing of the fibrous web after the safety device has been introduced into the fibrous web. The further treatment optionally includes a drying step applied before or after pressing the safety device into the fibrous web. Pressing the safety device into the fibrous web results in a fibrous sheet having a bulk region of fibers and sub-regions of fibers.

In a first aspect, a resulting fibrous sheet having opposing surfaces and a recess in one opposing surface comprises: a surface-applied safety device disposed in the recess; a fiber sub-region disposed below the recess; adjacent the safety device (disposed in the recess) and the sub-regions of the fiber body region; and the interface between the safety device and at least one surface of the fiber sheet. In a second aspect, the resulting fibrous sheet has one or more "soft edge" through holes extending from the recesses to opposing surfaces of the fibrous sheet. As used herein, reference to a body region adjacent to a safety device indicates that the body region is a three-dimensional region adjacent to the safety device along the x-axis in a cross-sectional view. As used herein, reference to a sub-region below the safety device indicates that the sub-region is a three-dimensional region along the y-axis that is at least partially covered by the safety device in cross-sectional view. The thickness of this sub-region is less than the thickness of the main body region such that the surface-applied safety device has a thickness difference of less than 80% of the thickness of the safety device or within the specified range and the implied sub-range as described above.

In one embodiment, the fibers in the subregion are further consolidated such that the amount of fibers in the subregion is substantially equal to the fibers in at least the immediately adjacent bulk region. In another embodiment, the amount of fibers in the subregion is substantially equal to the amount of fibers in the bulk region. As used herein, the term "substantially equal", as in reference to the amount of fibers in the main region and subregions, means that the amount of fibers in each region is within 80% to 100% of the amount in the other region, preferably 90% to 100%, as characterized in grams per square meter (gsm) of fiber. In a preferred embodiment, the amount of fibers in this subregion is equal to an amount in the range of 80% to about 100% of the bulk region, particularly the immediately adjacent bulk region.

As described herein, various thicknesses can be attributed to suitable safety devices. Therefore, various thickness differences are also envisaged. In one embodiment of the fibrous sheet, the security device has a thickness in the range of about 10 microns to about 75 microns. The thickness difference ranges from about -10 microns to about 30 microns; preferably 0 microns to about 25 microns; preferably about 0 um to about 15 um.

In one embodiment of both the first and second aspects of the invention, the fibrous sheet exhibits at least one of: (1) improved durability, (2) acceptable ink adhesion, (3) High cross-direction (CD) tensile strength, or (4) reduced backside print-through. As used herein, improved durability can be characterized by at least one of: (a) minimal or reduced damage at the interface compared to such sheets produced when the fibrous web is not sufficiently consolidated , or (b) almost no hinge effect. These effects can be quantified or assessed by known industry techniques for simulating the effects of document circulation. For example, the circulation of banknotes can be simulated with durability tests. One such suitable durability test is the "flow through simulation" test (CST). This is a wear test designed to simulate the mechanical and optical degradation a banknote experiences during its life cycle in circulation. The test is performed by attaching rubber washers each weighing 7.5 grams to the four corners of the banknote, then placing the weighted banknote in a grindstone calibrated to a speed of 60 revolutions per minute (RPM) for a 30-minute immobilization duration time (one (1) cycle) to execute. The tumbling action experienced by weighted banknotes causes mechanical and optical degradation. Controlled amounts of liquid and solid soiling agents (eg, soybean oil and clay) were then added to the stone grinder to simulate the effects of oil and soiling to which a banknote would normally be exposed during its life cycle. The banknotes were tested for mechanical degradation before and after each round of simulated degradation (e.g. surface and edge damage in the form of holes, tears, cuts, hinges, breakaways and rough edges, loss of tensile strength, folding endurance, tearing crack strength and perforation strength), optical deterioration (eg, deterioration of the color properties of printing inks), and contamination. Hinge effects and tearing at the interface are examples of mechanical degradation that are particularly suitable for this durability test.

张力测试仪或拉力测试仪的CD拉伸强度测试中，并且如本文下表2所示，根据本发明制造的纸表现出 CD拉伸强度增加，在与通过常规圆网将安全装置施加到完全成形的纤维幅材相比时，所测试的特性具有在约90％至约100％范围内的增加值。Tests for acceptable ink adhesion are known to those of ordinary skill in the art. For example, ink smear, which is the amount of ink transferred from one sheet to another in a stack of multiple fibrous sheets or documents, can be quantitatively measured by methods known to those of ordinary skill in the art. Similarly, tensile strength and backside print through can be quantified by methods known to those of ordinary skill in the art. For example, print-through can be quantified by known light reflectance or transmittance tests. using e.g.

In the Tensile Tester or Tensile Tester CD Tensile Strength Test, and as shown in Table 2 herein below, the paper made in accordance with the present invention exhibited an increase in CD Tensile Strength compared to the safety device applied through a conventional rotary wire to fully The properties tested have increases in the range of about 90% to about 100% when compared to formed fibrous webs.

As described, the fiber sheet has a fiber sub-region below the safety device and a fiber body region adjacent the safety device and the sub-region. Because the safety device is introduced when the fibrous web is sufficiently consolidated, the fibers in the regions of the fibrous web corresponding to the sub-regions in the sheet are not displaced by an amount that leads to the identified defects. In this way, the amount of fiber in the fiber sub-region is substantially equal to the amount of fiber in at least the immediately adjacent body region. As used herein, the term "proximate body region" refers to the three-dimensional region of the body region that adjoins the sub-region and the recessed portion of the safety device. The immediately adjacent body region extends radially from the recessed portion and the sub-region to a distance in the cross-sectional x-axis equal to the x-axis length of the sub-region. Given the volume difference between the immediately adjacent bulk region and the subregion, the fiber density in the subregion is greater than the fiber density in the immediately adjacent bulk region. The amount of fibers in the immediately adjacent bulk region and subregion is substantially equal such that, given the difference in volume between the two regions, the density in the subregion is greater than the density in the immediately adjacent bulk region. In an exemplary embodiment, the amount of fibers in the bulk region is in the range of 88.55gsm to 90.15gsm and the amount of fibers in the subregions is in the range of 87.26gsm to 90.69gsm. As used herein, "density" refers to the average amount of fibers in a volume.

In a second aspect of the invention, a fibrous sheet having opposing surfaces, one or more "soft edge" through-holes and a recess above the one or more through-holes comprises: a surface-applied safety device disposed in the recess fiber sub-regions disposed below the recesses, the fiber sub-regions defining one or more through holes; fiber body regions disposed adjacent to the safety device (disposed in the recesses) and sub-regions; and fiber sub-regions of safety devices and fiber sheets and the interface between the main area. The fiber sub-region extends along an area defined by the outer perimeter of the one or more through-holes and the one or more outer boundaries of the safety device.

As described herein, there are many safety devices suitable for use with the present invention. However, in one embodiment, the fiber sheet includes a security device having an array of cylindrical and/or non-cylindrical focusing elements and an array of image icons that optically interact with the focusing elements to produce at least one composite image. In preferred embodiments, the focusing elements are only cylindrical lenses or non-cylindrical lenses (eg microlenses). However, it is contemplated herein that the lens array includes a mixture of the two in various ratios.

As described herein, the safety device may be in the form of a strip or patch or other shape or geometry. In one embodiment, the safety device is present in the sheet in registration with at least one other feature in the sheet. Suitable additional features are described herein.

In another aspect, the present invention is a document comprising a fibrous sheet. Various documents are contemplated by the present invention. For example, suitable documents include, but are not limited to, banknotes, bonds, checks, traveler's checks, ID cards, lottery tickets, passports, stamps, stock certificates, and non-secure documents such as stationery items and labels and items for aesthetics. Multiple security devices can be incorporated into the fibrous web and thus can be found applied to the fibrous sheet and any resulting documents. Alternatively, in one embodiment, the document includes at least one surface-applied security device and at least one other security device, such as an embedded or partially embedded security device or security feature. Surface-applied security features may be registered with other features of the document, such as other security features or security or decorative features.

Fibrous sheets suitable for use in the present invention are paper or paper-like sheets. These sheets, which are single-layer or multi-layer sheets, can be made from a range of fiber types including synthetic or natural fibers or mixtures of both. For example, these sheets can be made from fibers such as abaca, cotton, flax, wood pulp, and blends thereof. As known to those skilled in the art, cotton and cotton/linen or cotton/synthetic fiber blends are preferably used for banknotes, while wood pulp is typically used for non-banknote security documents.

As noted above, it is contemplated that security devices for use with the present invention may take many different forms, including but not limited to strips, tapes, threads, ribbons, or patches (eg, microlens-based, holographic, and/or color-shifting security Wire).

A further understanding of the claimed invention will be facilitated by the following description of the accompanying drawings, which represent exemplary embodiments.

Conventional techniques are depicted in FIGS. 1 and 2 . Typically, as shown in Figure 1, a security device (11) is introduced during the wet stage of papermaking to embed the device (11) in a fibrous sheet or document (10). When the security device is surface applied using this method, the resulting fibrous sheet suffers from low flow-through durability, poor CD tensile strength, and high backside print-through. As mentioned elsewhere herein, it has been found that this is partly due to the displacement of the fibers (15) from the sub-regions (12) when the safety device (11) is introduced into the forming fiber web. As can be seen, the amount of fibers in the hinge region (14) is significantly reduced. This results in a weak interaction at the interface (17) between the security device and the substrate (18) of the fibrous sheet or document (10). This is especially noticeable at the interface edge (17a).

Disadvantages are also found in the conventional embodiment shown in Figure 2, where the safety device (21) is introduced during the drying stage of the papermaking or after the papermaking stage where the paper is fully consolidated. Here, the fibers ( 25 ) in the sub-regions ( 22 ) are so sufficiently consolidated that the safety device ( 21 ) cannot be pressed into the substrate ( 28 ). As a result, the thickness difference is high. High thickness differences have been associated with poor application of ink on the sheet or document (20). As a result, for embodiments in which the safety device is added during the drying stage, the safety device must be very thin in order to have a suitable thickness difference.

The present invention addresses at least one of these disadvantages. Figure 3 depicts one embodiment of the present invention. Here, unlike Figures 1 and 2, the safety device (31) is introduced during the wet phase when the fibers are sufficiently consolidated in the web, so that when the safety device is pressed into the base (38) of the fiber sheet (30) , a significant amount of fibers (35) are not displaced from the sub-regions (32). Instead, the fibers (35) are further consolidated or compacted below the safety device (31) and in the hinge area (34). This results in strong fiber interactions at the interface (37) and especially at the interface edge (37a). Furthermore, since the safety device (31) is introduced during the wet phase, it can be pressed into the substrate (38) to provide a low thickness difference.

Various methods and techniques can be used to introduce the safety device (41) into the fibrous web (49). In the preferred embodiment shown in Figure 4, the safety device (41) is presented in the form of a continuous web and is located on the Fourdrinier machine (40) immediately after the wet line (42) and after the couch roll (44) It is applied to the forming fibrous web (49) before and continuously between vacuum boxes (45a, 45b) which assist in the placement of safety devices into the fibrous web (49).

Figures 5 and 6 depict fibrous sheets or resulting documents (50, 60) of the present invention with multiple surface-applied security devices (52a, 52b, 53, 63a, 63b). The devices (52a, 52b, 53, 63a, 63b) are here presented in the form of patches (53, 63a, 63b) and strips (52a, 52b) of different sizes and shapes. Although not limited in terms of the placement position of the safety devices (52a, 52b, 53, 63a, 63b), in one embodiment of the present invention, the safety devices (eg 53, 63a, 63b) are passed through the introduction device ( Not shown) is cut or stamped and applied to the fibrous web (55) such that it registers with at least one other feature in the fibrous web, fibrous sheet or resultant document (60), such as a watermark (61). Figure 6 depicts an embodiment in which a plurality of security devices applied as patches (63a, 63b) are applied in registration with the watermark (61). The first patch (63a) is applied in lateral registration with the watermark (61), and the second patch (63b) is applied in longitudinal registration with the watermark (61). It is also envisaged that the security device (63a, 63b) is aligned with the watermark (61) such that at least one feature (not shown) in the patch (63a, 63b) is aligned with the watermark (61) or the fibrous web, fibrous sheet or resulting Other feature registrations in file (60). The documents (50, 60) have edges (59, 69) which, although depicted here as the sides of a parallelogram, may also be depicted in other shapes with other angles. Security devices (52a, 52b, 53, 63a, 63b) are applied to the fibrous web, fibrous sheet or document such that it does not extend beyond the edges (59, 69) of the document (50, 60). In a preferred embodiment, the safety device is provided on the surface such that it is positioned away from the edge without contact.

Example

Comparative Example 1 : Single Cycle Durability Testing of Surface Applied Safety Devices When the Fiber Web is Inadequately Consolidated

In a first comparative example, the fibrous sheet was produced according to a conventional wet stage process in which a safety device was introduced into the fibrous web when the water and/or moisture content in the fibrous web was greater than 98% during the papermaking process. As a result of the fiber displacement, the fibers in the hinge region (74) and sub-regions are displaced, resulting in a reduced interaction of the safety device (71) with the fiber base (78) of the fiber sheet (70) in these regions . A fibrous sheet (70) formed according to this process is shown in Figure 7A after passing a single cycle (30 min) of the flow-through simulation test. As a result of this single cycle, the fiber sheet (70) exhibits poor durability, at least as defined by the development of the hinge effect shown in the hinge region (74). The safety device (71) separates from the base (78) of the fibrous sheet (70) at points along the interface edge (77a).

Additionally, surface-applied security devices exhibit backside print-through. A group of five (5) people (P1, P2, P3, P4, P5) were asked to rate the degree of backside blow-through on a scale from 1 to 5, with 5 having the highest blow-through and 1 having the lowest blow-through. Panelists P1 and P4 rated backside blow-through as 4; panelists P2, P3, and P5 rated backside blow-through as 5. Figure 7B depicts a fibrous sheet (70) showing back print through. This will require some kind of backside camouflage coating to fix that.

张力测试仪测量纤维片材的横向(CD) 拉伸强度。将纸样品切割成125mm宽×15mm高的维度，使线垂直穿过样品的中心。然后将样品放入Instron(5965型)张力测试仪的钳口中，钳口之间的设定间距为40mm，并且使线在间隙中居中。然后将样品以38毫米/分钟的速率拉伸，直到样品断裂。重复此过程5次，这5个值的平均值是测试的报告结果。结果表明，CD拉伸强度在5.4 kg至6.3kg的范围内。Also use Type 5965

The Tensile Tester measures the cross-direction (CD) tensile strength of fibrous sheets. The paper sample was cut to a dimension of 125mm wide x 15mm high with the line running vertically through the center of the sample. The sample was then placed into the jaws of an Instron (Model 5965) tensile tester with a set spacing of 40mm between the jaws and the wire centered in the gap. The sample was then stretched at a rate of 38 mm/min until the sample broke. Repeat this process 5 times and the average of these 5 values is the reported result of the test. The results showed that the CD tensile strength was in the range of 5.4 kg to 6.3 kg.

Invention Example 1: Single Cycle Durability Testing of Surface-Applied Safety Devices When Fiber Webs Are Fully Consolidated

In a first inventive example, a fibrous sheet (80) is made according to the invention disclosed herein, wherein a safety device (81) is introduced into the fibrous web during the papermaking process when the moisture content of the fibrous web is less than 98%. There is sufficient interaction of the safety device (81) with the base (88) of the fiber sheet (80) as a result of reduced fiber displacement from the hinge region and increased fiber consolidation in the sub-regions. A fibrous sheet (80) formed according to this process is shown in Figure 8A after passing a single cycle of the flow-through simulation test. Clearly, the fibrous sheet (80) has improved durability relative to the material produced in Comparative Example 1 . Here, the fiber sheet (80) exhibits no hinge effect and is not damaged or separated from the base (88) of the fiber sheet (80) along the interface edge (87a) of the safety device (81). The fibrous sheet (80) remains intact, showing improved durability.

Furthermore, compared to Comparative Example 1, the surface-applied security device (81) exhibited less backside print-through. A group of five (5) people (P1, P2, P3, P4, P5) were asked to rate the degree of backside blow-through on a scale from 1 to 5, with 5 having the highest blow-through and 1 having the lowest blow-through. Panelist P2 rated backside blow-through as 1; panelists P1, P3, P4, and P5 rated backside blow-through as 2. Figure 8B depicts a fibrous sheet showing back print through. Alternatively, backside print-through is characterized by measuring across-line grayscale density. The paper samples were scanned on an Epson V750 Perfection flatbed scanner that had been calibrated using the IT8 reference target. The paper was scanned at 600 dpi as a grayscale image in reflected light with a black background behind the sample. Once the scan is captured, a density distribution of the selected area is generated. Using this function, we select regions across the line, where the software captures the gray value of each pixel in the selected region, and for this particular test, where the line runs vertically through the center of the selected region, the software The pixels are averaged, and the vertically averaged data points are reported for each horizontal pixel (for example, if the area is 20 pixels high by 200 pixels wide, for each horizontal position, the corresponding vertical pixel values will be averaged and will result in 200 output of data points). The resulting data is then plotted to show whether there are any significant shifts in the grayscale values within the sampled area. Density measurements are provided in Table 1. The Inventive Example results are provided in the top line, while the Comparative Example results are provided in the bottom line, indicating a significant drop in fiber density measurement as the measurement device traverses the opposite side of the safety device. Lower values indicate high backside blow-through. It can be seen that with the method of the invention (<90% water and/or moisture) the density values on the fibrous sheet remain relatively constant, whereas for the comparative example (>98% water and/or moisture) the density values are in the numerical value There is a well-recognized and significant reduction in . For the comparative example (>98% water), the average grayscale density across the line was 214; while for the inventive example (<90% water), the average grayscale density across the line was 226.

张力测试仪还测量了纤维片材(80)的横向(CD)拉伸强度。此处重复与上述相同的过程。结果表明，CD拉伸强度优于对比例1中所显示的。比较例的结果被描绘为表2中的第一条(＞98％水)，而本发明例的结果(<90％水)被描绘为表2中的第二条。Use Type 5965

The tensile tester also measured the cross direction (CD) tensile strength of the fibrous sheet (80). The same process as above is repeated here. The results show that the CD tensile strength is better than that shown in Comparative Example 1. The results for the Comparative Examples are depicted as the first bar in Table 2 (>98% water), while the results for the Inventive Examples (<90% water) are depicted as the second bar in Table 2.

Gray Density Measurements Across Lines

Table 1

Average increase in CD tensile strength of 25%

Table 2

Comparative Example 2: Three-Cycle Durability Testing of Surface-Applied Safety Devices When the Fiber Web is Inadequately Consolidated

In a second comparative example, the fibrous sheet (90) was manufactured according to a conventional wet stage process in which a safety device was introduced into the fibrous web when the water and/or moisture content in the fibrous web was greater than 98% during the papermaking process. As a result of the fiber displacement, the fibers in the hinge region and sub-regions are displaced during the introduction of the safety device (91), resulting in the safety device (91) and the base (98) of the fiber sheet (90) in these regions interaction is reduced. A fibrous sheet (90) formed according to this process is shown in Figure 9A after passing three cycles of the flow-through simulation test. As a result of these three cycles, the fibrous sheet (90) exhibited poor durability, at least as defined by the development of tears in the sheet along the interface edge (97a). The fiber sheet (90) is torn into two pieces along the interface edge (97a).

In addition, the surface applied security device (91) exhibits backside print-through. A group of five (5) people (P1, P2, P3, P4, P5) were asked to rate the degree of backside blow-through from 1 to 5, with 5 having the highest blow-through and 1 having the lowest blow-through. Panelists P1 and P5 rated backside blow-through as 5; panelists P2, P3 and P4 rated backside blow-through as 4. Figure 9B depicts a fibrous sheet (90) showing tearing and back print through. This will require some kind of backside camouflage coating to fix that.

Invention Example 2: Three Cycle Durability Testing of Surface-Applied Safety Devices When the Fiber Web is Fully Consolidated

In a second inventive example, a fibrous sheet (100) is made according to the invention disclosed herein, wherein a safety device (101) is introduced into the fibrous web during the papermaking process when the moisture content of the fibrous web is less than 98%. Relative to the situation in Comparative Example 1, there is sufficient interaction of the safety device with the base (108) of the fiber sheet (100) as a result of reduced fiber displacement from the hinge region and increased fiber consolidation in the sub-region. The fibrous sheet (100) formed according to this process is shown in Figure 10A after passing three cycles of the flow-through simulation test. Clearly, the fibrous sheet (100) has improved durability relative to the material produced in Comparative Example 2. Here, the fiber sheet (100) exhibits little to no hinge effect or damage along the interface edge (107a) of the safety device (101) with the base (108) of the fiber sheet (100). The fibrous sheet (100) remains intact, showing improved durability.

Furthermore, compared to Comparative Example 2, the surface-applied security device (101) exhibited less backside print-through. A group of five (5) people (P1, P2, P3, P4, P5) were asked to rate the degree of backside blow-through on a scale from 1 to 5, with 5 having the highest blow-through and 1 having the lowest blow-through. Panelist P1 rated backside blow-through as 2; P2, P4, and P5 rated backside blow-through as 1; and panelist P3 rated backside blow-through as 3. Figure 10B depicts a fibrous sheet showing improved backside print-through.

Figure 11 depicts an embodiment of the second aspect of the invention. Here, the fiber sheet is designated with reference numeral 110 . "Soft edge" through holes (111) are formed in the fibrous sheet (110) during the wet stage of papermaking before the fibrous sheet (110) becomes sufficiently consolidated. The safety device (112) is then introduced over the through hole (111) when the fiber sheet is sufficiently consolidated, so that when the safety device is pressed into the base (115) of the fiber sheet (110), a significant amount of Fibers (113) are not displaced from sub-regions (114). Instead, the fibers (113) are further consolidated or compacted below the safety device (112) in the sub-region (114) defining the through hole (111) and in the hinge region (116). This results in strong fiber interactions at the interface (117) and especially at the interface edge (117a). Furthermore, since the safety device (112) is introduced during the wet phase, it can be pressed into the substrate (115) to provide a low thickness difference. Furthermore, further consolidation in the sub-regions (114) greatly reduces, if not eliminates, the likelihood of the vias (111) becoming blocked or blocked, since the fibers are not displaced in this state.

As mentioned above, various methods and techniques can be used to introduce through holes (111) and safety devices (112) into the fiber sheet (110). In particular, the screen of a paper machine may be a continuously moving forming wire of a Fourdrinier wire machine or a cylinder wire of a rotary wire machine. In the preferred embodiment shown in Figures 12, 12A, 12B, the through holes 111 are formed using a patterned forming wire 118 on a Fourdrinier machine 119 provided with at least one water impermeable element 120 that prevents A sheet is formed in this area. The patterned forming wire (118) is depicted before (FIG. 12A) and after (FIG. 12B) discharge of papermaking stock from the headbox onto the forming wire. As shown in Figure 12B, sheet formation is prevented in the area of the water impermeable element (120). After the through holes ( 111 ) are formed and the fibrous sheet ( 110 ) becomes sufficiently consolidated, the safety device ( 112 ) is presented in the form of a continuous web and immediately after the wet line ( 122 ) and the couch roll ( 123 ) It is applied to form the fibrous sheet (110) before and continuously between vacuum boxes (124a, 124b) which facilitate the placement of safety devices into the fibrous sheet (110).

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Therefore, the breadth and scope of the present invention should not be limited by any of the exemplary embodiments.

Claims (21)

1. A fibrous sheet (110) having opposing surfaces, a recess in one opposing surface, and one or more through-holes (111) extending from the recess through the opposing surface of the fibrous sheet, wherein the one or more through-holes are "soft-edged" through-holes, the sheet comprising:

a fiber sub-region (114) disposed below the recess and surrounding the one or more through-holes, and an immediately adjacent body region disposed adjacent to the recess and the sub-region;

a surface-applied security device (112) disposed in the recess over the one or more through-holes; and

an interface (117) between a safety device applied to the surface and the sub-region of fibres and the body region,

wherein the security device applied through the surface further consolidates the fibers in the sub-region such that the amount of fibers in the sub-region is 80% to 100% of the amount of fibers in at least the immediately adjacent body region.

2. The fiber sheet of claim 1, wherein the one or more "soft-sided" through-holes have a unique irregularity in an edge region, a maximum diameter or width in the range of 4 to 15 microns, and a shape or profile selected from the group of circular, elliptical, star-shaped, parallelogram-shaped, and trapezoidal shapes, or combinations thereof.

3. The fibrous sheet material of claim 2, wherein the shape or contoured profile of the one or more "soft-edged" through-holes matches or is coordinated with a shape or contoured profile of the security device, an image displayed or projected by the security device, or both.

4. The fibrous sheet material of claim 1, wherein the security device is formed from a structural film and has a thickness of at least 10 microns.

5. The fibrous sheet material of claim 1, wherein the security device has a thickness in the range of 10 to 75 microns,

or

Wherein the surface applied security device has a thickness differential in the range of-10 microns to 25 microns.

6. The fibrous sheet of claim 1, wherein the fiber density in the sub-regions of fibers is greater than the fiber density in at least the immediately adjacent bulk region.

7. The fibrous sheet of claim 1, wherein the security device comprises an array of cylindrical or non-cylindrical focusing elements and an array of image icons that optically interact with the focusing elements to produce at least one composite image.

8. The fibrous sheet material of claim 1, wherein the security device is in the form of a strip or patch.

9. The fibrous sheet of claim 1, wherein the security device is in registration with at least one other feature on or within the fibrous sheet.

10. The fibrous sheet of claim 9, wherein the at least one other feature on or within the fibrous sheet is selected from the group of a watermark, a printed image, a relief structure, a fiber or group of fibers, another security device, or a combination thereof.

11. The fibrous sheet of claim 1, wherein the fibrous sheet is a banknote, and

wherein the surface-applied security device comprises an array of cylindrical and/or non-cylindrical focusing elements, and an array of image icons that optically interact with the focusing elements to produce at least one composite image,

wherein the thickness of the sub-regions of fibres is less than the thickness of the main region of fibres, such that recesses with side walls are formed in the surface of the sheet,

wherein the surface applied security device is disposed within the recess,

wherein the surface applied security device has a thickness in the range of 10 to 40 microns and a thickness difference in the range of 0 to 15 microns, and

wherein the security device is a strip or patch exposed on at least one side of the banknote.

12. A security or value document comprising the fibrous sheet of claim 1.

13. A security or value document according to claim 12, wherein the security device is introduced such that the security device is in registration with at least one other feature on or within the document, wherein the at least one other feature on or within the document is selected from the group consisting of a watermark, a printed image, a relief structure, a fibre or another security device,

or

Wherein the security or value document is a passport,

or

Wherein the security or value document is a banknote.

14. A method for surface applying a surface-applied security device (112) to a fibrous sheet (110), comprising:

forming one or more "soft-edged" through-holes (111) in the fibrous sheet during papermaking;

introducing the security device into or onto the formed fibrous web above the one or more through-holes at an introduction point during papermaking; and

the safety device applied by the surface further consolidates the fibers in a sub-area (114) of the fibrous sheet such that the amount of fibers in the sub-area is 80% to 100% of the amount of fibers in at least the immediate bulk area of the fibrous web.

15. The method of claim 14, wherein the one or more "softside" through-holes are formed in the fibrous sheet before the fibrous sheet becomes sufficiently consolidated during papermaking such that the level of moisture is greater than 98% by weight based on the total weight of the fibrous web.

16. The method of claim 14, wherein upon introduction of the surface-applied security device, the fibrous web is sufficiently consolidated at least at the point of introduction such that the level of moisture is less than 98% by weight, based on the total weight of the fibrous web.

17. The method of claim 14, wherein the fiber web is sufficiently consolidated such that the moisture is less than 95% by weight based on the total weight of the fiber web.

18. The method according to claim 14, wherein the security device is first presented as a continuous web, which is then cut and placed into or onto the fibrous web,

or

Wherein the security device introduced into or onto the fibrous web is in the form of a strip or patch,

or

Wherein the security device is introduced such that the security device is in registration with at least one other feature on or within the fibrous sheet or document comprising the fibrous sheet, wherein the at least one other feature on or within the fibrous sheet or document is selected from the group consisting of a watermark, a printed image, a relief structure, a fiber, or another security device.

19. The method of claim 14, further comprising

Providing the security device in the form of a continuous web;

cutting or stamping the continuous web in a continuous manner to form patches or strips;

wherein the application of the security device comprises continuously introducing the patch or strip to the fibrous web over the one or more "soft-edged" through-holes such that a fibrous body region, a fibrous sub-region and a negative relief having sidewalls are formed in the fibrous web.

20. The method of claim 14, wherein the introduction point of the safety device is continuously adjusted by adjusting tension on a continuous web.

21. A document comprising a fibrous sheet prepared according to the method of claim 14, wherein the fibrous sheet comprises a surface applied security device.

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