WO2014097146A1

WO2014097146A1 - Information support for printing on offset presses

Info

Publication number: WO2014097146A1
Application number: PCT/IB2013/061040
Authority: WO
Inventors: Jérôme DELRIEUX; Joseph Hemmerle
Original assignee: Arjowiggins Security
Priority date: 2012-12-18
Filing date: 2013-12-17
Publication date: 2014-06-26
Also published as: FR2999617A1

Abstract

The invention relates to an information support for offset printing, comprising a substrate coated on at least one of the faces thereof with a pigmentary layer suitable for offset printing, and comprising at least one security element, said printable face coated by the pigmentary layer having a non-random relief providing a surface roughness of between 1000 and 2500 mL/min measured according to the ISO 8791-2 norm.

Description

Information support for printing on offset presses

The invention relates to the field of security documents.

It relates more particularly to an information carrier printable on offset presses, coated with a printability layer, and a method of manufacturing such a support.

The support may be fibrous, in particular be constituted by a paper, preferably comprising at least 50% by weight of fibers, in particular cellulose fibers.

Among the printing techniques, the offset process is nowadays very widespread for quality printing because it makes it possible to produce large prints at an advantageous cost.

In order to obtain a better printing result, the fibrous substrates, in particular made by the papermaking method, are generally coated with a pigment layer. In particular, the following parameters can be used, alone or in combination, to judge print rendering: intensity and optical density of colors, definition, resolution, sharpness and brightness. Such a pigment layer generally comprises a binder, pigments and additives. It is generally deposited at more than 5 g / m ² / face, in particular about 10 g / m ² / face.

The coating of a pigment layer on a fibrous substrate promotes the drying of the inks and improves the print quality but goes against the security of the fibrous substrates insofar as the pigments of the inks deposited by offset printing remain on the surface and can therefore easily be erased. Impressions are therefore easily falsifiable.

There remains the need to be able to produce an information carrier coated with a pigment layer, providing protection against forgery, particularly mechanical, while being suitable for printing on offset presses.

In particular, there remains the need for an information medium providing protection against mechanical forgery.

The present invention aims precisely to provide an information medium satisfying the aforementioned requirements.

In particular, the present invention relates, according to a first aspect, to an information carrier intended for offset printing, comprising a substrate coated on at least one of its faces with a pigment layer adapted to the printing. offset, and less a security element, said printable face coated by the pigment layer having a non-random relief conferring a surface roughness measured according to ISO 8791-2 greater than 1 000 mL / min.

Said relief preferably extends over the entire printable face.

The substrate is more particularly fibrous, but the invention is not limited to a fibrous substrate.

It is advantageously a paper, in particular consisting of at least 50% by weight of fibers, preferably of cellulosic fibers.

The printable face preferably has a non-random relief conferring a surface roughness measured according to ISO 8791-2 greater than 1 000 mL / min, preferably between 1000 and 2500 mL / min, more preferably between 1500 and and 2500 mL / min, more preferably between 1500 and 2200 mL / min. The surface roughness is, for example, about 1800 ml / min.

The inventors have discovered that it is possible to secure the printing of security papers on offset presses, without affecting their printability by this technique, by implementing a printable surface having a determined roughness.

It has already been proposed to modify the surface of papers, especially security. For example, the document EP 1 252 389 describes a security paper comprising a security zone providing protection against mechanical falsification and comprising a set of cells formed in hollow in the paper and whose depth is 50 to 90% of the maximum thickness of the paper around the cells. The printing of such paper is of good quality for inkjet printing or for laser printing.

Also disclosed in GB 191501084 is a process for processing and printing fiduciary papers implementing a compression, distinct from an embossing, between dies allowing both to create an impression in the paper and to produce a visible gray color, which can not be reproduced by photography.

However, to the knowledge of the inventors, it has never been proposed security media according to the invention, specifically adapted to printing on offset press and providing protection against mechanical forgery.

Thus, an information carrier according to the invention is advantageous in several ways. Firstly, it is perfectly compatible with printing on offset presses, in particular because of the coating on the surface intended for printing a conventional pigment layer, suitable for offset printing. In particular, the implementation of a pigment layer makes it possible to meet the standards required for printing on offset presses conventionally used and with the aid of inks that are usually used.

Furthermore, an information carrier according to the invention advantageously has good printability properties for printing on offset presses. In particular, the printability of such a support meets the requirements for offset printing, in particular as regards the adhesion of the ink to the printed medium, and the transfer of the ink between the blanket and the ink. support.

According to another of its aspects, the present invention thus relates to a method of printing on offset presses, implementing as a printing medium, an information medium comprising a substrate coated on at least one of its faces. a pigment layer suitable for offset printing and at least one security element, said printable face coated by the pigment layer having a non-random relief conferring a surface roughness measured according to ISO 8791-2 greater than 1,000 ml / min.

Said printable face preferably has a non-random relief conferring a surface roughness measured according to ISO 8791-2 greater than 1000 ml / min, preferably between 1000 and 2500 ml / min, more preferably between 1500 and 1500 ml / min. and 2500 mL / min, more preferably between 1500 and 2200 mL / min and even more preferably about 1800 mL / min.

Moreover, as demonstrated in the following examples, supports, particularly paper, according to the invention are particularly resistant to attempts to falsify, including attempts at mechanical forgery, for example using an eraser or a scalpel. In fact, the falsification of a paper according to the invention, printed on offset presses, can not take place without great difficulties.

More particularly, a mechanical forgery, for example using an eraser or a scalpel, will damage the rough surface and / or mark the pigment layer by respectively creating a defibration and / or a variation of brightness between the zones. falsified and non-falsified areas. Application FR 2,687,417 describes a sheet coated with a glossy layer which becomes matt under the action of a scrub or a scraping. This request is not suitable for all products as it excludes the production of matte leaves. Moreover, the proof of the mechanical falsification, in other words the change in brightness of the layer, can be difficult to observe depending on the observation conditions, in particular according to the type, the diffuse nature and the incidence of the illumination.

There is therefore a need to have a sheet that can be coated indifferently with a glossy or matte layer and the proof of mechanical forgery is more easily observable.

Thus, a mechanical forgery, for example using an eraser or a scalpel, will damage the rough surface including tearing fibers (also called "defibration") and / or destruction of the relief. Indeed, the relief of the sheet promotes access to the sheet and thus the defibration and / or the destruction of the relief of the sheet, especially during forgery by scrubbing or scraping.

Also, as illustrated in the examples which follow, the prints of an information carrier according to the invention can not be erased, in particular with an eraser, without creating any damage to the surface of the support. Without wishing to be bound by a theory, it can be assumed that the reliefs of the rough surface according to the invention will be able to trap the ink. During an attempt at mechanical forgery, in particular using an eraser, the ink thus housed in the hollows of the relief of the rough surface will be more difficult to achieve, whether by scratching or scrubbing.

According to a particularly preferred embodiment, the support according to the invention comprises one or more chemical or biochemical infallification reagents that react in a colored manner with at least one counterfeiting agent, as described more precisely below. Such an information carrier according to the invention thus also has good resistance to attempts at chemical forgery. In fact and surprisingly, as demonstrated in Example 2 which follows, the presence of the pigment layer on the surface of the paper is not detrimental to the sensitivity of the paper to the chemical forgery products included in the support.

According to yet another of its aspects, the invention relates to a method of manufacturing an information carrier intended for printing on offset presses, in particular as defined above, characterized in that it comprises at least the steps consisting of: (i) forming, on at least the face of a substrate for printing, a nonrandom relief; and

(ii) coating the printing surface with a pigment layer suitable for offset printing;

the relief formed in step (i) conferring on said printable face coated with the pigment layer, a surface roughness measured according to ISO 8791-2 greater than 1000 ml / min, preferably between 1000 and 2500 ml / min, more preferably between 1500 and 2500 mL / min, more preferably between 1500 and 2200 mL / min and even more preferably about 1800 mL / min;

step (ii) being performed after or before step (i).

Preferably, step (i) is performed by embossing the face intended for printing.

As developed subsequently, the method of manufacturing a paper according to the invention can be implemented according to several variants. In particular, the formation of the relief on the face of the substrate, in particular by embossing, can be carried out in a wet phase or in a dry phase during the preparation of the paper, and according to the technique employed, according to an order of the steps (i) and ( ii) variable.

In the remainder of the text, the expression "printing face" or "face intended for printing" is used to distinguish the two faces of the substrate, the printing face being the one on which the different treatments will be operated (embossing , coating) before offset printing

More particularly, the term "printable face offset" or simply "printable face" refers to the face of the substrate intended for printing, after coating of the pigment layer which makes it suitable for printing on offset presses.

In a variant, the two faces of the substrate are "printing faces" or "faces intended for printing", or "printable offset faces" or "printable faces". Other characteristics and advantages of the information medium and its manufacturing method will emerge more clearly on reading the description and the examples that follow, given for illustrative and non-limiting purposes.

In the remainder of the text, the expressions "between ... and ...", "ranging from ... to ..." and "varying from ... to ..." are equivalent and mean to mean that terminals are included unless otherwise stated.

Unless otherwise indicated, the expression "comprising / including a" shall be understood as "comprising / including at least one".

SUBSTRATE

The substrate considered according to the invention is preferably fibrous.

It may comprise paper fibers known to those skilled in the art, for example cellulosic fibers.

According to a particularly preferred embodiment, the substrate consists of at least 50% by weight of fibers, preferably of natural fibers.

According to one variant, the fibrous substrate preferably comprises at least 50% of short natural fibers (derived from hardwoods).

More particularly, the substrate may comprise a mixture of long natural fibers (derived from softwoods) of 5 to 40%, short natural fibers (from hardwoods) of 50 to 95%, and recycled fibers of 0 to 20%.

Short natural fibers (from hardwood) can, for example, be used to promote defibration during an attempt at mechanical forgery.

The natural fibers may be formed in whole or in part of cellulosic fibers, in particular all of them being cellulosic fibers.

According to another variant embodiment, the substrate comprises synthetic fibers chosen, for example, from rayon fibers, in particular fibran or viscose, or from a thermoplastic material, in particular a polyamide, a polyester, a a polyolefin and / or a mixture of such fibers.

According to a particular embodiment, the substrate comprises at least one mineral filler. The mineral filler (s) may be present in a mass content ranging from 5 to 35%, relative to the total weight of the substrate.

They may be more particularly chosen from silica, sodium silicates and aluminosilicates, carbonates, in particular calcium, talc, kaolin, alumina hydrate, titanium dioxide and mixtures thereof. The presence of mineral fillers notably makes it possible to improve the printability properties and facilitates the degradation of the surface of the substrate during an attempt to falsify

According to another variant embodiment of the invention, the substrate is made of plastic. It may be more particularly based on polymers chosen from polyesters including poly (ethylene terephthalate), polypropylenes, polyethylenes, polyvinyl chloride, polycarbonate and mixtures thereof.

According to a particular embodiment, the substrate may have a basis weight ranging from 60 to 400 g / m ² , in particular from 80 to 250 g / m ² .

The grammage is measured according to ISO 536.

According to a particular embodiment, the substrate may comprise one or more security elements.

These security elements, known to those skilled in the art, are described more precisely later.

According to a particularly preferred embodiment, the substrate comprises at least one chemical or biochemical tampering reagent as developed more particularly subsequently. It is more particularly colorless reagents capable of causing, by acid-base chemical reaction, oxidation reduction or by solubilization, visible color reactions in case of falsification of the prints by acids, bases, oxidants (such as javel) or solvents (eg toluene).

By way of example, the substrate of an information carrier according to the invention may incorporate one or more security elements chosen from invisible fibers in daylight and having a fluorescence under a radiation at 365 nm, Hilite particles. ™ invisible in daylight and having fluorescence under 365 nm radiation and chemical tampering reagents.

The Hilite ™ particles described for example in the EP 226 367 application are agglomerates with a dimension of approximately 200 μπι of finer fluorescent particles.

PIGMENTAL LAYER

According to one of the essential features of the invention, the substrate is coated, on at least its face intended for printing, with a pigment layer adapted to offset printing. As mentioned above, it is a treatment of the printing surface, commonly used for printing on offset presses and to ensure maximum adhesion of the ink.

The skilled person can, on the basis of his general knowledge, suitably choose a pigment layer, particularly with regard to the nature of the substrate and / or the ink used for offset printing and adapt the amount of layer deposited on the substrate in order to obtain good printability.

The pigment layers are mixtures in an aqueous medium of pigments, for example calcium carbonate, kaolin, silica and / or titanium dioxide and additives, chosen for example from a dispersant, an antifoam and / or pH corrector, in a binder for example starch, polyvinyl alcohol or a latex.

The substrate thus coated on one of its faces by the pigment layer according to the invention is suitable for printing on offset presses.

The coating of the pigment layer can be carried out online on the paper machine or offline.

The coating of the pigment layer may be carried out by any coating, impregnation, surfacing, printing or spraying technique known to those skilled in the art, and more particularly adapted for pigmentary layers for offset printing. . It is preferably made by coating.

Thus, according to the invention, the coating of the pigment layer is a mass and / or surface treatment. It is preferably at least a surface treatment to promote the effect of the pigment layer on the adhesion of inks.

It can for example be performed using an air knife coater, a curtain coater, a coater or blade coater, a bar coater or a coater, a coater with a metering roll, a gravure coater, an impregnator, a size press, or a film transfer device, notably "Twin HSM" (marketed by BTG) or "Film press", a printing device, in particular gravure printing, and a spraying device.

Advantageously, such a coating technique allows the pigment layer to be applied homogeneously and to marry the relief of the surface intended for printing. It is therefore particularly a so-called "contour" coating applicable in particular by means of a curtain coater or an air knife coater. According to a particular embodiment, the pigment layer is applied to the printing surface at a rate of 2.0 to 20.0 g / m ² , preferably 5.0 to 15.0 g / m ² , and more preferably about 10.0 g / m ² .

INTERMEDIATE OR IMPREGNATION LAYER

According to a particular embodiment, the information carrier according to the invention may comprise at least one impregnation of the substrate or an intermediate layer between the surface of the substrate and the pigment layer, formed from a composition to be applied (also called impregnating solution or coating or coating).

Thus, the process for producing a paper according to the invention may comprise, prior to the step (ii) of coating the pigment layer, an application step on at least the face intended for the printing of a composition. More particularly, according to an alternative embodiment, the application step is performed, subsequently to the formation (i) of the non-random relief on the face of the substrate intended for printing, and prior to the coating (ii) of the pigment layer.

Such an application step is known to improve the quality of the paper surface. In particular, it makes it possible to homogenize the fibrous sub-layers of the paper, leaving a more uniform and even surface, which makes it possible to obtain a better print quality.

It is understood that in the context of the present invention, such an application, when it is carried out after the step (i) of formation of the relief, is implemented under favorable conditions so that the information carrier as well treated always meets the requirement of surface roughness required according to the invention. The coating with the pigment layer decreases the roughness a little. The skilled person can therefore play on the amount of deposited pigment layer to adjust the desired final roughness.

It is up to those skilled in the art to choose the composition to be applied adapted to the nature of the paper and the pigment layer.

The composition to be applied may comprise a binder, more particularly chosen from starches, latices, polyvinyl alcohols, carboxymethyl celluloses (CMC) and their mixtures, as well as bonding agents and / or resistance agents in the state. wet to enhance the water resistance of the substrate. The latices may be chosen from acrylic latices, styrene butadiene or butadiene and more preferably for reasons of durability, in particular UV resistance and aging resistance, among acrylic latices.

The composition to be applied may also comprise one or more chemical reagents identical to those introduced with the fibers in order to reinforce the protection of the substrate.

According to one particular embodiment, the composition intended for impregnating the substrate or for forming the intermediate layer is applied to the printing surface at a rate of 1 to 10 g / m ² , preferably of approximately 5 g / m 2. ² .

The application can be carried out by any method or device known to those skilled in the art of impregnation or coating, for example using an impregnator, a size press (also called "size press"), a coater with an air knife or doctor blade, a curtain coater, a Champion coater, a gravure coater or a film transfer coater, for example such as a Twin HSM coater from BTG or Film Press.

The application of the composition intended to form the intermediate layer or the impregnation may be carried out by any technique of coating, coating, impregnation, surfacing, printing or spraying known to those skilled in the art .

Thus, according to the invention, the application of the composition intended to form the intermediate layer is a mass and / or surface treatment. It is preferably at least a mass treatment, especially impregnation, in order to homogenize the fibrous sub-layers of the paper, leaving a more uniform and regular surface. Such a surface can therefore limit the penetration of the pigment layer into the substrate and thus make it possible to obtain a homogeneous and regular pigment layer, that is to say in particular of constant thickness and / or of flat surface according to the method of selected application for said pigment layer.

It can for example be performed using an air knife coater, a curtain coater, a coater or blade coater, a bar coater or a coater, a coater with a metering roll, a gravure coater, an impregnator, a size press, or a film transfer device, notably "Twin HSM" (marketed by BTG) or "Film press", a printing device, in particular gravure printing, and a spraying device. So advantageously, it is an impregnation or surfacing applicable especially by means of an impregnator, a sizing press (or "Size Press") or a film transfer device, in particular "Twin HSM Or "Film press".

Preferably, the composition for forming the intermediate layer or the impregnation is applied to the printing surface by means of a gluing press.

ROUGH PRINTABLE SURFACE

According to another essential characteristic of the invention, the printable face coated by the pigment layer has a non-random relief conferring a surface roughness measured according to ISO 8791-2 greater than 1 000 ml / min.

Preferably, the printable face has a surface roughness measured according to ISO 8791-2 of between 1000 and 2500 ml / min.

Preferably, the printable face has a surface roughness measured according to the ISO 8791-2 standard of between 1500 and 2200 ml / min.

Preferably, the printable face has a roughness of about 1800 mL / min.

Preferably, the relief is a texture visible to the naked eye in grazing light.

The texture does not constitute a security element within the meaning of the invention.

The inventors have discovered that such a surface roughness does not disturb the quality of printing on offset presses while advantageously making it possible to increase the difficulty of falsifying the prints, in particular with the aid of an eraser and / or a scalpel as described more specifically in the following examples.

Roughness Bendtsen

Surface roughness is measured according to the Bendtsen method according to ISO 8791-2 ("Paper and board, determination of roughness / smoothness (air flow methods), Part 2: Bendtsen method").

More particularly, the Bendtsen roughness measures the passage of air in mL / min between a metal crown and the surface of the substrate. The perfectly ground metal crown is placed on the sample to be measured, itself placed on a smooth, flat and hard surface. Air is injected at constant pressure into the center of the crown, and the measurement indicates the passage of air leaking between the crown and the surface of the paper. The rougher the surface of the substrate, the easier air will escape and the higher the measured value. Conversely, the less the substrate will be rough, the lower the measured value will be. It is for a person skilled in the art to form, on the face of the substrate intended for printing, a non-random relief, suitable for imparting to the printable face coated with the pigment layer, the desired roughness.

The surface intended for printing may have a relief having a succession of "bumps" and "hollows", more particularly distributed in a repetitive pattern.

Such a relief advantageously allows a trapping of the ink in the hollows, thus making it more difficult to attempt falsification.

"Bumps" shall be taken to mean all parts of the surface above the average amplitude of the relief patterns of the sheet, and as "hollow" all parts of the surface of the sheet below the surface. average amplitude of the relief patterns of the sheet.

The relief preferably has a hollow amplitude - bumps, equal to S _p + S _v , greater than 50, preferably greater than 60 μπι. S _p and S _v are respectively the maximum height of the bumps and the maximum depth of the hollows.

The relief preferably has a quadratic mean gradient S _Aq greater than

S _p , S _v and S _Aq are defined according to the ISO 25178 standard and calculated from the measurement carried out using an Altisurf of an area of 10 x 10 mm with a measurement step of 5 μπι then of mathematical filtering by means of a polynomial web. The mathematical filtering makes it possible to eliminate the low frequency contribution of possible deformations (folds, lack of flatness ...).

According to a particular embodiment, the bumps, or respectively the hollows, are of narrow and elongated shape with irregular edges or alternatively frustoconical or dome-shaped. The hollows or bumps, respectively, are also wide enough to allow the deposition of the ink during printing, avoid the formation of unprinted dots in the bottom of the hollows and thus ensure good printability of the substrate.

In an exemplary implementation of the invention, the printing face has a periodic relief in the form of lines or even geometric figures, especially cellular, for example lozenges. Preferably the presence of the bumps or hollows remains discrete, and does not affect the appearance of the print or the appearance of at least one watermark that can otherwise be present. The bumps may be identical to those present on the "FINEZZA" and "CONCETTO" papers marketed by WITCEL and whose surface appearance corresponds respectively to FIGS. 2 and 3.

Bumps such as those on the paper "FINEZZA" and "CONCETTO" are preferred because the hollows are deeper and the amplitude hollow - bumps larger resulting in more defibering during forgery.

According to a particular embodiment, the hollow-bump amplitude is greater than 50 μπι, preferably greater than 60 μπι and more preferably between 60 and 100 μπι.

Bumps or hollows in a pointed form, in particular not rounded, are particularly preferred. In fact, during an attempt at mechanical forgery, for example by scrubbing, the degradation of the layer and eventually the defibration of the fibrous substrate will occur more easily, thus leaving a trace of the act of falsification.

The user will be able to feel a "rough" or "grainy" appearance of the printed surface.

Formation of the relief

Such a relief may be formed on the face of the substrate intended for printing by any method of watermarking, embossing, marking or graining known to those skilled in the art.

Such a relief is formed on the face of the substrate intended for printing preferably by embossing, marking or graining.

It is for a person skilled in the art to implement any technique of watermarking, embossing, marking or graining to achieve the adequate relief that provides the surface roughness required according to the invention.

Such relief marking devices are for example described in document WO 2004/003294.

The rough surface may for example be obtained by a device chosen in particular from:

embossing rollers,

the filigree rollers,

filigranous canvases,

the leafy rollers, textured rolls, in particular by embossing or etching, in particular of synthetic material, for example of rubber, or of metal, the rollers provided with a fabric, in particular metal,

marking or graining markers and

the grain presses.

According to a particularly preferred embodiment, the relief is formed by means of an embossing device, where the sheet passes between two rollers, at least one of which is on the side of the face to be printed is an engraved metal roll. .

The pattern of the metal roller (s) makes it possible to obtain the desired reliefs. The relief can thus be obtained otherwise than by a conventional technique of filigree formation, for example by a device other than a filigree roller or a filigranous fabric.

According to a first variant embodiment, the formation of the relief on the printing surface of the paper, in particular by embossing, is carried out in a wet phase during the formation of the paper sheet, more particularly at the level of the drip or level of pressing in the papermaking process.

All the devices mentioned above may be suitable for this first variant. In addition to the use of different reliefs or patterns, more or less pressure can be applied by these devices on the substrate, in particular to obtain the desired roughness.

In the context of this variant, the formation of the relief, in particular by embossing, marking or graining, is carried out prior to coating by the pigment layer.

Thus, according to one of its variants, the present application relates to a method of manufacturing an information carrier intended for printing on offset presses, in particular as defined above, characterized in that it comprises at least the steps consisting of:

(a) having a substrate having on at least one of its faces a nonrandom relief, and

(b) coating said surface with a pigment layer suitable for offset printing, said relief implemented in step (a) conferring on said printable surface coated with the pigment layer a surface roughness measured according to the ISO 8791-2 standard; greater than 1,000 mL / min. Said printable face preferably has a non-random relief conferring a surface roughness measured according to the ISO 8791-2 standard of between 1000 and 2500 ml / min, more preferably between 1500 and 2200 ml / min and even more preferentially. about 1800 mL / min.

In particular, the substrate of step (a) can be formed beforehand by embossing, marking or graining said substrate face, especially in the wet phase.

According to another embodiment of the invention, the formation of the relief on the printing face is carried out in the dry phase of the preparation of the paper, and more particularly by embossing. This dry phase embossing step may be performed by grain presses, textured rolls or embossing rollers. These devices can apply pressure and / or heating to the substrate, in particular in order to obtain the desired roughness.

In the context of this variant embodiment, the formation of the relief, in particular by embossing, may be carried out before or after the coating by the pigment layer.

While the formation of the wet-phase relief is done on-line on the paper machine, the formation of the relief in the dry part can be done on-line on the paper machine, preferably when it is carried out before the coating, or offline, preferably when performed after coating.

Thus, according to another variant embodiment, the subject of the present invention is also a method of manufacturing an information carrier intended for printing on offset presses, in particular as defined above, characterized in that it comprises minus the steps of:

(c) having a substrate coated on at least one of its faces with a pigment layer suitable for offset printing, and

(d) forming, on said coated face, a non-random relief, in particular by embossing, in particular carried out in the dry phase, so as to confer on said face coated by the pigment layer, a surface roughness measured according to ISO 8791-2 greater than 1,000 mL / min.

Said printable face preferably has a non-random relief conferring a surface roughness measured according to the ISO 8791-2 standard of between 1000 and 2500 ml / min, more preferably between 1500 and 2200 ml / min and even more preferentially. about 1800 mL / min. The substrate used in step (c) can be made beforehand by coating on the face of the substrate with a pigment layer, as described above.

According to another variant embodiment, the substrate used in step (c) may be chosen from substrates already coated with a pigment layer suitable for offset printing.

According to a variant of the invention, the subject of the application is a method for manufacturing an information carrier intended for offset printing, characterized in that it comprises at least the steps consisting of:

(i) forming, on at least the face of a substrate for printing, a nonrandom relief; and

the relief formed in step (i) conferring on said printable face coated by the pigment layer, a surface roughness measured according to the ISO 8791-2 standard greater than 1000 ml / min;

step (ii) being performed after or before step (i).

Said printable face preferably has a non-random relief conferring a surface roughness measured according to the ISO 8791-2 standard of between 1000 and 2500 ml / min, more preferably between 1500 and 2200 ml / min and even more preferentially. about 1800 mL / min.

In the context of the implementation of a plastic substrate, as described above, the embossing can be carried out under pressure using grain presses, textured metal rollers or embossing rollers, with or without heating applied to rollers to facilitate the deformation of the plastic substrate.

In general, the embossing in dry part will be preferred to the embossing partly wet. The dry-part embossing is preferably carried out after coating of the pigment layer. Indeed, the coating of the pigment layer is likely to reduce the amplitude of the relief which goes against the demonstration, particularly by defibration, of an attempt at mechanical forgery.

SECURITY ELEMENT

The information carrier according to the invention may comprise one or more security elements.

All or part of the security element may be visible. The security element does not consist of a local modification of the relief or the texture of the article.

The security elements may for example be integrated with the substrate, in particular the fibrous substrate, or present on the surface of the information carrier.

The security element (s) present may have first, second or third level security features.

Some of the security features are detectable to the eye, daylight or artificial light, without the use of a particular device. These security elements comprise for example colored fibers or boards, fully or partially printed or metallized wires. These security elements are called first level.

Other types of additional security elements are detectable only with a relatively simple apparatus, such as a lamp emitting in the ultraviolet (UV) or infrared (IR). These security elements comprise, for example, fibers, boards, strips, wires or particles. These security elements may be visible to the naked eye or not, being for example luminescent under a lighting of a Wood lamp emitting in a wavelength of 365 nm. These security elements are said to be second level.

Other types of security elements require for their detection a more sophisticated detection device. These security elements are for example capable of generating a specific signal when they are subjected, simultaneously or not, to one or more external excitation sources. The automatic detection of the signal makes it possible to authenticate, if necessary, the document. These security elements comprise, for example, tracers in the form of active materials, particles or fibers capable of generating a specific signal when these tracers are subjected to optronic, electrical, magnetic or electromagnetic excitation. These security elements are said to be third level.

The information carrier may comprise as security element one or more reagents, so-called chemical or biochemical infadification and / or authentication and / or identification reagents, which may in particular react respectively with at least one agent falsification and / or authentication and / or identification.

According to a particular embodiment, the information carrier comprises at least one chemical or biochemical infalsification reagent. Said at least one reagent chemical or biochemical infalsification is in particular introduced in bulk in the fibrous substrate and / or in the intermediate layer described above.

The tampering agent may for example be used to prevent the chemical erasure of an impression or a mark produced by laser irradiation of the substrate, with at least one of the following compounds:

an oxidizer,

- a strong or weak base,

a strong or weak acid, or

a polar or apolar solvent.

The tampering agent can prevent chemical erasure with oxidants, for example such as sodium hypochlorite. In this case, the tampering agent may be chosen from the following compounds:

derivatives of manganese, nickel, cobalt or cerium, and in particular their salts, p-diaminodiphenyl, its sulphate derivatives or its phosphate derivatives,

vanadium derivatives,

4,4'-diaminodinaphthyl (Ι),

S, N orthophenylene isothiourea,

the primulin,

guanidine derivatives such as diarylguanidine, for example diphenylguanidine, or

thiazole, benzothiazole or aminonaphthothiazole derivatives.

The tampering agent can prevent chemical erasure with strong bases for example such as sodium hydroxide, and / or weak for example such as sodium carbonate. In this case, the tampering agent may be chosen from the following compounds:

derivatives of manganese, nickel, cobalt or cerium, and in particular their salts, colored indicators such as paranitrophenol, phenolphthalein, pyranine or a xanthene derivative.

The tampering agent can prevent chemical erasure with strong acids for example such as sulfuric acid, and / or weak for example such as oxalic acid. In this case, the tampering agent may be chosen from the following compounds:

a colored indicator such as a xanthene derivative, ferric ferrocyanide with added ferric chloride, or

a derivative of thiazole, benzothiazole or aminonaphthothiazole.

The tampering agent may make it possible to prevent chemical erasure with polar solvents, for example such as ethanol, and / or apolar solvents, for example such as toluene. In this case, the tampering agent may be chosen from the dyes which are insoluble in water but soluble in oils and solvents. These dyes are used in particular for coloring petroleum derivatives.

The substrate may comprise, for example, a single tampering agent which makes it possible to prevent chemical erasure by several erasing products. It may for example comprise manganese sulfate, and preferably manganese chloride, to prevent the erasure of the mark with bases, for example such as soda but also with oxidants such as hypochlorite of sodium, by the appearance in both cases of a brown spot revealing the attempt of erasure.

The substrate may also include several tampering agents to respectively prevent the chemical erasure with several erasing products, including the appearance of revealing stains of each of the erasing products. It may, for example, comprise a thiazole derivative and a xanthene derivative in order to prevent the chemical erasure with oxidants such as sodium hypochlorite, respectively, by the appearance in particular of an orange spot indicative of an attempt to erasure, but also the chemical erasure with bases such as soda, by the appearance in particular of a blue spot revealing an attempt to erase and finally the chemical erasure with acids such as sulfuric acid, by the appearance in particular of a pink spot revealing an attempt of erasure.

The information medium may comprise at least one authentication and / or identification structure, the security elements being superimposed at least partially, or totally, on the authentication and / or identification structure. The authentication and / or identification structure may be chosen from at least one of the following elements: a watermark, an optically variable element such as a hologram, a strip element, a foil, a patch, a wire security, an impression. SECURITY ARTICLES

The information carrier according to the invention may form all or part of a security article.

Thus, the present application also relates to a security article, in particular a security document, comprising, in particular consisting of, an information medium as described above.

The security article may be more particularly a security document, chosen in particular from a means of payment, in particular a bank note or a check, an identity document, in particular an identity card, a driving license , a visa or a passport page, but also a coupon (or "voucher"), a label, a diploma, a stamp.

According to one embodiment, it is a check, a coupon (or "voucher"), a label, a diploma or a stamp.

The invention will now be described by means of the following examples and figures.

These examples are of course given by way of illustration and not limitation of the invention.

FIG. 1: schematic representation of an information carrier (1) according to the invention, for example a check, comprising a security thread (2) and one or more security elements (3), for example fibers or invisible particles in daylight and having a fluorescence under radiation at 365 nm or chemical or biochemical tampering reagents that react in a colored manner with at least one counterfeiting agent.

Figures 2 and 3: Photographs of "FINEZZA" and "CONCETTO" papers, respectively.

Figure 4: "STYLE" paper photograph cited below.

EXAMPLE 1

1.1 Preparation of a paper according to the invention

substratum

The substrate is a Laserguard ^® paper composed of 65% short fibers, 25% long fibers, and 10% recycled fibers, and containing 22% mineral weight in dry weight relative to the total dry weight of fibers such as kaolin . In particular, the paper is chemically protected according to CBS1.

This paper includes, as a security feature, a watermark, visible colored synthetic fibers and synthetic fibers invisible in daylight and having a fluorescent color under 365 nm radiation, Hilite ™ invisible particles in daylight and having fluorescence under 365 nm radiation and chemical or biochemical tampering reagents.

Paper-0

By way of comparison, the paper ("Papier-0") is watermarked in a partially wet line and then coated with an intermediate layer by impregnation in a size-press (also called "size-press") by a composition comprising starch, latex, bonding agents and chemical reagents such as those introduced with the fibers, at a rate of about 5 g / m ² / side.

Paper-0 '

The paper-0 is then coated using an air knife coater with the following pigment layer and at a rate of 12 g / m ² / face. This gives the paper-0 '.

Paper- 1

Paper-1 is made by the same method as Papier-0. It undergoes moreover an embossing, in part wet before impregnation, on both sides by idler rollers equipped with a motive identical to that present on the papers "STYLE" marketed by the company WITCEL and whose appearance of surface corresponds to Figure 4.

Paper-2 and paper-3

Paper-2 and Paper-3 are made by the same process as Paper-0 '. They also undergo off-line dry-side embossing (that is to say outside the paper machine) by embossing rollers provided with identical patterns to those respectively present on the "FINEZZA" and "CONCETTO" papers marketed by the company. WITCEL company and whose surface appearance corresponds respectively to Figures 2 and 3.

1.2. Evaluation of papers

Roughness Bendtsen

Paper-0, having not undergone any embossing step, has a roughness of 102 ml / min, and the coated but unembossed paper-0 'has a roughness of 59 ml / min. It is noted that the coating reduces the roughness of the support. The paper-1, paper-2 and paper-3 embossed sheets respectively have a roughness of 676, 1971 and 1836 ml / min. The roughness is measured after coating with the pigment layer and, if appropriate, embossing.

Impressions on offset presses

The papers are printed on an offset press, with good printing results.

The surface roughness of the Papier-2 and Papier-3 according to the invention in no way disturbs the offset printability properties. In particular, these papers have a print quality superior to that of Papier-0 and equivalent to that of Papier-0 '.

Protection against mechanical forgery

tests

Mechanical forgery tests consist of attempting to erase the printed characters from the paper using a white eraser and / or a scalpel. The mechanical forgery tests were carried out on characters printed in black.

Results

The visualization of the falsification is evaluated by assigning a "-" index when the falsification is not visible and "+" to "+++" according to the fact that the falsification is more and more visible.

The results are summarized in the table below.

Table 2

The prints made on the paper-0, not according to the invention because uncoated and not embossed, can not be easily erased using an eraser and / or a scalpel without creating damage to the surface paper, and therefore without evidence of forgery. Paper-0, however, has an average print quality due to the lack of a printability layer.

The coated paper, which does not conform to the invention because it is not embossed, has a very good print quality, but the prints made on this paper can be easily erased with an eraser and / or scalpel without damaging the surface of the paper, and therefore without evidence of forgery.

The paper-1 coated and slightly embossed, not according to the invention because having a roughness of less than 1000 ml / min, has a good print quality but the prints made on this paper can be easily erased with the help of an eraser and / or a scalpel without creating damage to the surface of the paper, and thus without leaving evidence of forgery. The embossing being light, the roughness of the paper-1 is not high enough to retain the ink in the hollows of the relief.

On the other hand, the falsification of the Papier-2 and Papier-3 according to the invention, having a roughness according to the invention, does not take place without considerable difficulties, and without degrading said papers. This falsification of Papier-2 and Papier-3 is more visible because the erased or erased characters remain slightly visible. The embossed structure retains the ink in the hollows of the relief, not allowing the characters to be erased without simultaneously degrading the printability layer and the paper surface (defibration). The scrubbing and / or erasure thus leaves a less clean surface state on said papers according to the invention, and thus makes apparent attempts to falsify.

EXAMPLE 2

Protection against chemical falsification

tests

The reactivity of the Papier-0, Papier-2 and Papier-3 sheets to the chemical forgery products is tested according to "CBS1" standards and with an apolar solvent (toluene).

The touch test according to the CBS1 2 cm protocol consists in applying to a defined surface (circle of 2 cm in diameter), a precise quantity of reagent at a precise concentration (acid, base, oxidizing agent, etc.) according to said standard. . Reagents react with those contained in the paper causing the substrate to stain.

A measurement of Delta E * (ΔΕ *) under D65 illuminant at 10 ° (USAV Diaphragm 420 and 6.6 mm) is then made which corresponds to the difference in hue between the initial substrate and the color reaction zone.

The CBS1 standard therefore sets a minimum Delta E * value for paper to be protected. Chemical falsification tests were performed on part of a printed image with a blue sky and a green field, on a solid gray area and on black printed text.

Results

The results are collated in the following Table 1.

Table 1

The papers show all after chemical forgery, evidence of falsification due to the appearance of irreversible staining, caused by the chemical tampering reagents included in the paper base. On the other hand, it is not possible to totally eliminate the ink from the Papier-2 and Papier-3 according to the invention.

Papier-2 and Papier-3, produced on embossed bases show levels of chemical reactivities to strong acids, strong bases, bleach and solvents according to the CBS1 specifications comparable to those of uncoated paper-0 and in particular in accordance with said specifications.

Thus, the coating of the printability layer and the embossing does not affect the desired chemical reactivity for the security papers.

The invention is not limited to the examples described.

Claims

An information carrier for offset printing, comprising a substrate coated on at least one of its faces with a pigment layer suitable for offset printing, and comprising at least one security element,

said printable face coated by the pigment layer having a non-random relief conferring a surface roughness measured according to ISO 8791-2 between 1500 and 2500 mL / min, more preferably between 1500 and 2200 mL / min and more preferably about 1800 mL / min.

2. Information carrier according to the preceding claim, the printable face having a texture visible to the naked eye in grazing light.

3. Information carrier according to one of the preceding claims, the relief being formed of bumps and recesses arranged in a repetitive manner.

4. Information carrier according to any one of the preceding claims, characterized in that the average amplitude of the relief is greater than 50 μπι, preferably greater than 60 μιη and more preferably between 60 and 100 μιη.

5. Information carrier according to any one of the preceding claims, the substrate being fibrous, in particular consisting of at least 50% by weight of fibers, preferably of cellulosic fibers.

6. Information carrier according to any one of the preceding claims, said security element being selected from the chemical or biochemical tampering reagents that react in a colored manner with at least one tampering agent.

An information carrier according to any one of the preceding claims, comprising at least one intermediate or impregnating layer between the surface of the substrate and the pigment layer, formed from a composition applied to the substrate, in particular comprising at least one tackifier, a latex, a starch, or carboxymethyl cellulose (CMC).

8. Information carrier according to one of the preceding claims comprising a printing, performed by offset printing.

9. A method of manufacturing an information carrier for offset printing, in particular as defined in any one of claims 1 to 8, characterized in that it comprises at least the steps consisting of: (a) having a substrate having on at least one of its faces a nonrandom relief, and

(b) coating said surface with a pigment layer suitable for offset printing, said relief implemented in step (a) conferring on said printable surface coated with the pigment layer a surface roughness measured according to the ISO 8791-2 standard; between 1500 and 2500 mL / min, more preferably between 1500 and 2200 mL / min and even more preferably about 1800 mL / min.

10. A method of manufacturing an information carrier for offset printing, in particular as defined in any one of claims 1 to 8, characterized in that it comprises at least the steps consisting of:

(d) forming, on said coated face, a non-random relief, in particular by embossing, in particular carried out in the dry phase, so as to confer on said face coated by the pigment layer, a surface roughness measured according to ISO 8791-2 between 1500 and 2500 mL / min, more preferably between 1500 and 2200 mL / min and even more preferably about 1800 mL / min.

11. A method of manufacturing an information carrier for offset printing, in particular as defined in any one of claims 1 to 8, characterized in that it comprises at least the steps consisting of:

the relief formed in step (i) conferring on said printable face coated with the pigment layer, a surface roughness measured according to the ISO 8791-2 standard of between 1,500 and 2,500 ml / min, more preferably between 1,500 and 2 200 mL / min and even more preferably about 1800 mL / min;

step (ii) being performed after or before step (i).

12. The method of claim 1 1, the step (i) being carried out using an embossing device, marking or graining, in particular using a textured roll, including material synthetic, preferably rubber.

13. Method according to one of claims 1 1 and 12, the step (i), in particular embossing, marking or graining, being carried out in the wet phase, prior to the coating (ii) of the layer pigment.

14. Method according to one of claims 11 to 13, step (i), in particular embossing, being carried out in the dry phase, before or after the coating step (ii)

15. A method according to any one of claims 11 to 14, the step (ii) being carried out using a coating device, in particular using an air knife coater.

16. A method according to any one of claims 11 to 15, comprising before step (ii) of coating of the pigment layer, a step (iii) of applying an intermediate layer or impregnating on the less the face intended for printing, in particular by a solution comprising at least one bonding agent, a latex, a starch, or CMC.

17. A method of printing on offset presses, implementing as a printing medium, an information carrier comprising a substrate coated on at least one of its faces with a pigment layer suitable for offset printing and at least one security element, said printable face coated with the pigment layer having a non-random relief imparting a surface roughness measured according to the ISO 8791-2 standard of between 1000 and 2500 ml / min, more preferably between 1 and 500 and 2200 mL / min and even more preferably about 1800 mL / min, said method comprising a step of printing on an offset press.

18. Security article comprising, in particular consisting of, an information carrier as defined in any one of claims 1 to 8.

19. Security article according to the preceding claim, characterized in that it is a security document, in particular selected from a means of payment, in particular a bank note or a check, an identity document, in particular an identity card, a driver's license, a visa or a passport page, and more preferably a check, a voucher, a label, a stamp, a diploma.