RU2782023C2 - Machine-readable protective signs - Google Patents

Abstract

FIELD: information protection.

SUBSTANCE: invention can be used in protection of documents from forgery. A protective paint for printing of a machine-readable protective sign is proposed, containing one or more IR radiation-absorbing materials selected from a group consisting of iron (II) orthophosphates without crystallization water of the general formula Fe₃(PO₄)₂ with a crystal graftonite structure, metal-containing iron (II) orthophosphates without crystallization water, metal-containing iron (II) phosphonates without crystallization water, metal-containing iron (II) pyrophosphates without crystallization water, metal-containing iron (II) metaphosphates without crystallization water of the general formula Fe_aM_b(PO_c)_d, where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3, and M is one or more metals selected from a group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, transition metals (block d) selected from Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Mn, Cu, Zn, Co, Ni, Ag, Au, metals and semimetals of the third, the fourth, and the fifth main groups, selected from B, Al, Ga, In, Si, Sn, Sb, Bi, and lanthanoids, and mixtures thereof. The protective paint is a protective paint fixed by oxidation, or a protective paint cured under the action of radiation in UV and visible range, or a protective paint fixed under the action of heat, or a combination thereof. A machine-readable protective sign and its production method, a protected document and its authentication method are also proposed.

EFFECT: invention allows for increase in a degree of document protection.

15 cl, 3 dwg, 15 tbl

Description

[001] The present invention relates to the field of security inks suitable for printing machine-readable security features on a substrate, in particular on security documents or articles.

BACKGROUND OF THE INVENTION

[002] In connection with the continuous improvement in the quality of color photocopies and printed works, and in an attempt to protect security documents such as banknotes, documents of value or cards, travel tickets or cards, tax stamps and product labels that do not have reproducible effects, from counterfeiting, falsification or illegal reproduction, it has become common practice to include various safeguards in these documents.

[003] Security features, for example, for security documents, can be broken down into "hidden" and "overt" security features. The protection provided by latent security features is based on the concept that such features are hidden, which usually require special equipment and knowledge to detect, while “overt” security features can be easily detected using the naked human senses, for example , such features may be visible and/or tactilely detectable and yet still be difficult to manufacture and/or replicate.

[004] Machine-readable inks, such as, for example, magnetic inks, luminescent inks, and IR-absorbing inks, are widely used in the field of security documents, in particular for banknote printing, to provide the security document with an additional latent security feature. The protection of a protected document against forgery and illegal reproduction provided by hidden security features is based on the concept that special equipment and knowledge are usually required to detect such features. In the field of security and protection of valuable documents and valuable commercial goods from forgery, falsification and illegal reproduction, it is known in the art to use machine-readable security inks through various printing processes, including printing processes using high viscosity or paste inks such as offset printing, letterpress printing and gravure printing. printing (also referred to in the art as engraved steel die embossing or engraved copper plate printing), liquid inks used for rotogravure printing, flexographic printing, screen printing and inkjet printing.

[005] Widely known and used in the field of security are security features containing absorbing infrared (IR) radiation materials. Commonly used IR absorbing materials in the field of security are based on the absorption of electromagnetic radiation due to electronic transitions in the spectral range from 780 nm to 1400 nm (the range provided by the CIE (Commission Internationale de l'Eclairage - International Commission on Illumination)), while the specified part of the electromagnetic spectrum, as a rule, refers to the region of near infrared radiation. For example, IR-absorbing features are embedded in banknotes for use with automatic banknote processing equipment, in banking and commercial sectors (ATMs, vending machines, etc.) to recognize banknotes of a certain denomination and certify their authenticity, in particular, for distinguishing them from replicas made on color copiers. IR absorbing materials include organic compounds, inorganic materials, glasses containing significant amounts of IR absorbing atoms or ions. Representative examples of IR absorbing compounds include, but are not limited to, carbon black, diimmonium or ammonium quinone salts, polymethines (e.g. cyanines, squarenes, croconenes), phthalocyanine or naphthalocyanine type compounds (IR absorbing pi system), dithiolenes, quaterrylenediimides, salts (such as, for example, fluorides, chlorides, bromides, iodides, nitrates, nitrites, sulfites, sulfates, phosphates, carbonates, borates, benzoates, acetates, chromates, hexaborides, molybdates, manganates, ferrates, organosulfates, organosulfonates, organophosphonates , organophosphates and phosphonotungstates) of a metal (such as, for example, a transition metal or lanthanide), metal oxides (such as, for example, indium tin oxide, antimony tin oxide in the form of nanoparticles and doped tin(IV) oxide), nitrides metals.

[006] Due to its strong absorption in the visible region, carbon black is not a preferred security material because, due to its strong absorption in the visible region, it limits the freedom to design a security document to be protected from counterfeiting or illegal reproduction.

[007] Ideally, security features containing infrared (IR) absorbing materials for authentication purposes should not absorb in the visible range (400 nm to 700 nm), for example, so that they can be used in all types of visibly colored paints, and also in markings that are invisible to the naked eye, while at the same time exhibiting strong absorption in the near infrared range (700 nm to 1400 nm), making it easily recognizable by standard banknote processing equipment.

[008] Organic NIR absorbers generally have limited use in security applications due to their inherent low thermal stability and the difficulty of their manufacture.

[009] Inorganic IR absorbing compounds showing improved properties were disclosed in WO 2007/060133 A2, which developed security paints to provide security features whose design freedom is not limited to absorption of said IR absorbing compounds in the visible range electromagnetic spectrum. WO 2007/060133 A2 discloses gravure inks containing an IR absorbing material consisting of a transition element compound, the IR absorption of which results from electronic transitions within the d-shell of transition element atoms or ions. In particular, WO 2007/060133 A2 describes copper(II) phosphates, Cu(II) pyrophosphates, copper(II) metaphosphate, hydrated iron(II) phosphate Fe ₃ (PO ₄ ) ₂ 8H ₂ O, vivianite), hydrated nickel(II) phosphate (Ni ₃ (PO ₄ ) ₂ 8H ₂ O) and Ca ₂ Fe(PO ₄ ) ₂ 4H ₂ O (Anapait) as IR-absorbing materials.

[010] Therefore, there remains a need for security inks containing an IR absorbing material for printing machine-readable security features that have advantages over the prior art and are similar or even more suitable than known IR absorbers in terms of absorption of near infrared radiation, and at the same time have high chemical resistance, high reflectance in the visible range and do not cause toxicological or environmental problems.

BRIEF DESCRIPTION OF THE INVENTION

[011] Accordingly, the aim of the present invention is to eliminate the above disadvantages of the prior art.

[012] In a first aspect, the present invention provides a security ink for printing a machine-readable security feature, said security ink comprising one or more IR absorbing materials selected from the group consisting of

iron(II) orthophosphates without water of crystallization of the general formula Fe ₃ (PO ₄ ) ₂ with the crystal structure of graphtonite,

metal-containing iron(II) orthophosphates without water of crystallization, metal-containing iron(II) phosphonates without water of crystallization,

metal-containing iron(II) pyrophosphates without water of crystallization,

metal-containing iron(II) metaphosphates without water of crystallization of the general formula Fe _a M _b (PO _c ) _d , where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3, and M is one or more metals selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, transition metals (block d ), in particular Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Mn, Cu, Zn, Co, Ni, Ag, Au, metals and semimetals of the third, fourth and fifth main groups , in particular B, Al, Ga, In, Si, Sn, Sb, Bi, and lanthanides, and mixtures thereof,

wherein said protective paint is

an oxidation-curing protective paint containing from about 0.01% to about 10% by weight of one or more desiccants, the weight percentage being based on the total weight of the oxidation-curing protective paint, or

UV/VIS curable protective paint containing from about 0.1 wt.% to about 20 wt.% of one or more photoinitiators, the weight percentage being calculated based on the total weight of the UV/VIS curable areas of protective paint, or

a heat-curable protective paint containing from about 10% to about 90% by weight of one or more solvents selected from the group consisting of organic solvents, water, and mixtures thereof, the weight percentage being calculated based on the total weight of the curable exposed to the heat of a protective paint, or a combination of the two.

[013] Also described and claimed herein are a machine-readable security feature made from the security ink described herein, and methods for obtaining said machine-readable security features, wherein said methods include the step a) of application, preferably by means of a printing process selected from a group consisting of gravure printing, screen printing, flexographic printing, rotogravure printing and inkjet printing using a flex print head, the protective ink described herein, onto a substrate.

[014] Also described and claimed herein are security documents comprising a machine-readable security feature and a security document comprising a first region consisting of a machine-readable security feature described herein and a second region consisting of a security feature made of ink. containing one or more compounds absorbing in another region of the electromagnetic spectrum (UV or visible), or consisting of a security feature made of machine-readable magnetic ink containing one or more magnetic compounds, thereby forming said combined security feature.

[015] Also described and claimed herein are methods for authenticating a security document described herein, said methods including the steps of:

a) provide a security document described herein and containing a machine-readable security feature made from the ink described herein;

b) illuminating the machine-readable security feature at at least two wavelengths, wherein one of said at least two wavelengths is in the visible range and the other of said at least two wavelengths is in the near-IR range,

c) detecting the optical characteristics of the machine-readable security feature by sensing light reflected by said machine-readable security feature at at least two wavelengths, wherein one of said at least two wavelengths is in the visible range and the other of said at least two wavelengths waves is in the near-IR range, and

d) determine the authenticity of the document to be protected by the detected optical characteristics of the machine-readable security feature.

[016] Surprisingly, it has been found that the use of the IR absorbing materials described herein in protective paints combines strong NIR absorption properties, high visible reflectance, and high chemical resistance.

[017] The IR absorbing materials described herein can be relatively easily manufactured at a relatively low cost, and are characterized, for example, by high chemical resistance compared to organic or metallic organic absorbers. They do not contain water of crystallization, as a result of which all radiation is absorbed by the complex itself, and not part of it is absorbed by crystallization water. In addition, protective paints containing these one or more IR absorbing materials show particularly strong absorption in the near IR range, but are highly reflective in the visible range.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1A-B shows X-ray diffraction patterns (XRD) of Fe ₃ (PO ₄ ) ₂ without water of crystallization with the structure of graftonite (IR-absorbing material IR-A 1, Fig. 1A) and KFePO ₄ without water of crystallization (IR-absorbing material IR -A 2, Fig. 1B).

In FIG. 2A and 2B show DSC curves of Fe ₃ (PO ₄ ) ₂ with a graftonite structure and without water of crystallization (IR-absorbing material IR-A 1, FIG. 2B) and Fe ₃ (PO ₄ ) ₂ without water of crystallization (IR-absorbing material). radiation of the material IR-A 3, Fig. A).

Figure 3 shows a plot of visible and near-IR reflectance (security feature printed on a paper substrate with gravure inks containing 40 wt.% IR-absorbing materials IR-A 1 (straight line) , IR-A 2 (dashed line) and IR-A 3 (dashed/dotted line).

DETAILED DESCRIPTION

[018] To interpret the meaning of the terms discussed in the description and set forth in the claims, the following definitions should be used.

[019] In the context of this document, the singular form of an object indicates one or more objects and does not necessarily limit it to a single number.

[020] In the context of this document, the term "about" means that the specified amount or value may be a certain value or some other, approximately the same value. This phrase implies that similar values in the range of ±5% of the specified value provide equivalent results or effects in accordance with the present invention.

[021] In the context of this document, the term "and/or" or "or/and" means that either all or only one of the elements of the specified group can be present. For example, "A and/or B" would mean "only A or only B, or both A and B".

[022] In the context of this document, the term "at least" means one or more than one, for example, one, or two, or three.

[023] The term "security document" refers to a document that is typically protected from forgery or falsification by at least one security feature. Examples of secure documents include, without limitation, documents of value and valuable commercial goods.

[024] The expression "ultraviolet" (UV) is used to refer to the spectral range from 100 to 400 nm, "visible" (VID) is used to refer to the spectral range from 400 to 700 nm, "infrared" (IR) is used to refer to the spectral range between wavelengths from 780 nm to 15000 nm, and near infrared (NIR) is used to refer to the spectral range between wavelengths from 780 nm to 1400 nm (ranges provided by the CIE (Commission Internationale de l'Eclairage - International Commission on Illumination), disclosed in Sliney D.H., Eye (the Scientific Journal of the Royal College of Ophthalmologists, 2016, 30(2), pp. 222-229).

[025] The present invention further provides security inks comprising one or more of the IR absorbing materials described herein for printing machine-readable security features. In the context of this document, the term "machine-readable security feature" refers to an element that exhibits at least one distinctive property that can be detected by a device or machine, and which can be contained in a layer in such a way as to represent a method for authenticating said layer or article, containing the specified layer, using specific equipment to authenticate it.

[026] The machine-readable properties of the security feature described herein are provided by one or more of the absorbent materials described herein contained in the security ink described herein.

[027] The machine-readable security features comprising one or more of the IR absorbing materials described herein advantageously exhibit high reflectance in the visible range (400 nm to 700 nm) and low reflectance in the near infrared range (780 nm up to 1400 nm), thus providing effective authentication and recognition by standard equipment and standard detectors, including those equipped with high-speed banknote sorting machines, since such detectors rely on the difference in reflectance at selected wavelengths in the visible and near-IR ranges .

[028] The present invention further contemplates using one or more of the IR absorbing materials described herein as machine-readable compounds in the security inks described herein to print machine-readable security features on the substrate described herein, by means of a printing process, preferably selected from the group consisting of gravure printing, screen printing, rotogravure printing, flexographic printing or inkjet printing using a flexo print head.

[029] One or more infrared absorbing materials described herein are preferably present in the protective paint described herein in an amount of from about 5 to about 60 wt.%, with the weight percentage calculated based on the total weight protective paint.

[030] One or more of the IR absorbing materials described herein are suitable for obtaining machine-readable security features by combining a) the presence of ferrous and phosphate anions or phosphonate anions and a lack of water of crystallization and b) the absence of an inversion center in the crystal structure specified materials. One or more of the IR absorbing materials described herein do not have an inversion center, as in the case of iron(II) orthophosphate without water of crystallization with the formula Fe ₃ (PO ₄ ) ₂ with the structure of gratonite, but also in the case of mixed metal-containing iron(II) compounds of the general formula Fe _a M _b (PO _c ) _d described herein, the Laporte rule no longer applies and the absorption is correspondingly higher.

[031] In one or more IR absorbing materials, phosphorus is present in the oxidation step (V). The low percentage of phosphorus in the other oxidation stages cannot be excluded as a result of manufacture and must be protected from unavoidable impurities. The products according to the present invention are obtained from phosphoric acid (H ₃ PO ₄ ) and its condensates (polymers). Orthophosphates have an anionic structural unit [PO ₄ ^3- ], pyrophosphates and diphosphates have a structural unit [P ₂ O ₇ ^4- ], and cyclic metaphosphates have a structural unit 00=[(PO ₃ ^- ]n.

[032] One or more of the IR absorbing materials described herein are selected from the group consisting of iron(II) orthophosphates without water of crystallization of the general formula Fe ₃ (PO ₄ ) ₂ with the crystal structure of graftonite, metal-containing iron(II) orthophosphates ) without water of crystallization, metal-containing iron(II) phosphonates without water of crystallization, metal-containing iron(II) pyrophosphates without water of crystallization, metal-containing iron(II) metaphosphates without water of crystallization of the general formula Fe _a M _b (PO _c ) _d , where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3, and M is one or more metals selected from the group, consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, transition metals (block d), in particular Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W , Mn, Cu, Zn, Co, Ni, Ag, Au, metals and semimetals of the third, fourth and fifth new groups, in particular B, Al, Ga, In, Si, Sn, Sb, Bi and lanthanides; and their mixtures.

, b≈11,56

с≈6,14

α≈90,00°, β≈99,35°, γ≈90,00°. В элементарной ячейке содержится восемь формульных единиц Fe_1,5PO₄. Фосфор тетраэдрически координирован кислородом, и железо(II) находится в трех различных четырехуровневых слоях (4е), каждый с различной координационной геометрией: 1-кратно искаженный октаэдрический, причем один из координированных ионов кислорода находится значительно дальше (d~2,68

), и 2-кратно тригонально-бипирамидальный. Следовательно, атомы железа в системе графтонита координированы без центра инверсии. По сравнению с другими известными кристаллическими структурами, содержащими кристаллизационную воду (например, вивианит октагидрата Fe₃(PO₄)₂ 8Н₂О) или с центром инверсии относительно центрального атома железа (например, Fe₃(PO₄)₂ в кристаллической структуре саркопсида), кристаллическая структура графтонита ортофосфата железа(II) без кристаллизационной воды с формулой Fe₃(PO₄)₂, описанного в данном документе, демонстрирует улучшенные характеристики.[033] According to one embodiment, the protective paint described herein comprises one or more IR absorbing materials selected from the group consisting of iron(II) orthophosphates without water of crystallization of general formula Fe ₃ (PO ₄ ) ₂ with crystalline graffonite structure. In other words, the protective paint described herein contains monometallic iron(II) orthophosphate without water of crystallization of the general formula Fe3(P04)2, while the expression "monometallic" means that the product contains only iron(II) as the metallic (cationic ) element. The crystal structure of graphtonite iron(II) orthophosphate without water of crystallization with the formula Fe ₃ (PO ₄ ) ₂ has a crystal system that is monoclinal, with the space group being P21/c and the lattice constants being approximately a≈8.81

, b≈11.56

c≈6.14

α≈90.00°, β≈99.35°, γ≈90.00°. The unit cell contains eight Fe _1.5 PO ₄ formula units. Phosphorus is tetrahedrally coordinated by oxygen, and iron(II) is in three different four-level layers (4e), each with a different coordination geometry: 1-fold distorted octahedral, with one of the coordinated oxygen ions located much farther away (d~2.68

), and 2-fold trigonal-bipyramidal. Consequently, the iron atoms in the graftonite system are coordinated without an inversion center. Compared to other known crystal structures containing water of crystallization (for example, vivianite octahydrate Fe ₃ (PO ₄ ) ₂ 8H ₂ O) or with an inversion center relative to the central iron atom (for example, Fe ₃ (PO ₄ ) ₂ in the sarcopside crystal structure) , the crystal structure of iron(II) orthophosphate graphtonite without water of crystallization with the formula Fe ₃ (PO ₄ ) ₂ described herein shows improved performance.

[034] According to another embodiment, the protective paint described herein comprises one or more IR absorbing materials selected from the group consisting of metal-containing iron(II) orthophosphates without water of crystallization, metal-containing iron(II) phosphonates without water of crystallization , metal-containing iron(II) pyrophosphates without water of crystallization, metal-containing iron(II) metaphosphates without water of crystallization of the general formula Fe _a M _b (PO _c ) _d , and mixtures thereof, where a is a number from 1 to 5, b is a number >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3, and M is one or more metals selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, transition metals (block d), in particular Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Mn, Cu, Zn, Co, Ni , Ag, Au, metals and semimetals of the third, fourth and fifth main groups, in particular B, Al, Ga, In, Si, Sn, Sb, Bi, and lanthanides. In other words, the protective paint described herein comprises one or more IR absorbing materials selected from the group consisting of mixed metal iron(II) orthophosphates without water of crystallization, metal iron(II) pyrophosphates without water of crystallization, or metal-containing iron(II) metaphosphates without water of crystallization of the general molecular formula Fe _a M _b (PO _c ) _d described in this document, while the expression "containing mixed metals" means that the product contains at least one additional metal in addition to iron(II) as metallic (cationic) components, in which case its abbreviation is "M".

[035] Preferably, the protective paint described herein comprises one or more IR absorbing materials selected from the group consisting of metal-containing iron(II) orthophosphates without water of crystallization, metal-containing iron(II) phosphonates, metal-containing iron pyrophosphates( II) or metal-containing iron(II) metaphosphates of the general formula Fe _a M _b (PO _c ) _d , where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3; and M is one or more metals selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba. Preferably, the protective paint described herein contains a metal-containing iron(II) orthophosphate without water of crystallization, a metal-containing iron(II) phosphonate, a metal-containing iron(II) pyrophosphate, or a metal-containing iron(II) metaphosphate of the general formula Fe _a M _b (PO _c ) _d described herein, where M is potassium (K), magnesium (Mg) and zinc (Zn) or a combination thereof, preferably only potassium (K) or in combination with either magnesium (Mg) or zinc (Zn ). More preferably, metal-containing iron(II) orthophosphate without water of crystallization, metal-containing iron(II) phosphonate without water of crystallization, metal-containing iron(II) pyrophosphate without water of crystallization, or metal-containing iron(II) metaphosphate without water of crystallization of the general formula Fe _a M _b (PO _c ) _d described herein is KFePO ₄ , K(Fe _0.75 Zn _0.25 )PO ₄ or K(Fe _0.75 Zn _0.25 )PO _{4 .}

[036] One or more of the IR absorbing materials described herein are independently characterized by a specific size. As used herein, the term "size" refers to a statistical property of said IR absorbing materials. As is known in the art, each of said one or more IR absorbing materials can be independently characterized by measuring the particle size distribution (PSD) of a sample. Such PSDs typically describe the fractional number (relative to total number, weight, or volume) of particles in a sample as a function of size-related characterization of individual particles. A commonly used size-related characteristic describing individual particles is the "equivalent circle" (CE) diameter, which corresponds to the diameter of a circle whose area is equal to the area of the orthogonal projection of the material. The following values are reported in this annex: d(v,50) (in this document abbreviated d50 is the value of the CE diameter in microns that divides the PSD into two parts of equal total volume: the lower part represents 50% of the total volume of all particles, which corresponds to those particles with a CE diameter less than d50, the upper part represents 50% of the total particle volume, which corresponds to those particles with a CE diameter greater than d50 D50 is also known as the median of the particle volume distribution,

d(v,90) (abbreviated in this document as d90 is the value of the CE diameter in microns, which divides the PSD into two parts with different total volumes, so that the lower part represents 90% of the total volume of all particles, which corresponds to those particles with a CE diameter less than d90 and the top represents 10% of the total volume of particles with a CE diameter greater than d90, and

similar to d(v,10) (abbreviated here as d 10 is the value of the CE diameter in microns that separates the PSD into two parts with different total volumes, so that the bottom part represents 10% of the total volume of all particles, which corresponds to those particles with a diameter CE less than d10 and the top represents 90% of the total volume of particles with a CE diameter greater than d10.

[037] The average particle size (d50 value) of each of the one or more IR absorbing materials described herein is preferably from about 0.01 µm to about 50 µm, more preferably from about 0.1 µm to about 20 µm, and even more preferably from about 1 µm to about 10 µm.

[038] A variety of experimental methods are available for measuring PSD, including, but not limited to, particle size distribution analysis, electrical conductivity measurements (using a Coulter counter), laser diffractometry (for example, Malvern Mastersizer), acoustic spectroscopy (for example, Quantachrome DT-100), differential sedimentation analysis (eg CPS devices) and direct optical granulometry. Laser diffractometry was used to determine the PSDs specified in this application (tool: (Cilas 1090); sample preparation: IR absorbing material was added to distilled water or ethyl acetate, depending on the water solubility of the material to be measured, until laser obscuration reached the working level of 13-15%, in accordance with the ISO 13320 norm.

[039] The IR absorbing materials described herein are preferably produced by a method comprising the following steps, in which:

a) prepare a mixture containing:

i) iron (A) compounds selected from Fe(III) compounds, Fe(III)/Fe(II) compounds and mixtures thereof, in percentages from about 20 wt.% to about 90 wt.% by weight of the mixture, selected from the group consisting of oxides, hydroxides, oxide hydroxides, carbonates, carboxylates such as oxalates, formates, acetates, citrates, lactates, orthophosphates, phosphonates, metaphosphonates, pyrophosphates, sulfates and mixtures of the foregoing,

ii) reducing agents (B) in a percentage of from about 5 wt.% to about 50 wt.% by weight of the mixture selected from the group consisting of phosphonic acid [H ₃ PO ₃ ], phosphorus trioxide [P ₂ O ₃ ], phosphinic acid [H ₃ PO ₂ ], phosphorus tetroxide [P ₂ O ₄ ], hypodiphosphoric acid [H ₄ P2O ₆ ], diphosphoric acid [H ₄ P ₂ O ₅ ], hypodiphosphonic acid [H ₄ P ₂ O ₄ ], Fe salts and salts M of the aforementioned acids and mixtures of the foregoing as solids, aqueous solutions or suspensions,

iii) an optional phosphate donor (C) in a percentage of from about 0 wt.% to about 50 wt.% by weight of the mixture, selected from phosphoric acid [H ₃ PO ₄ ] as an aqueous solution, metal phosphate [M _x (PO ₄ ) _z ] or metal hydrogen phosphate [M _x HY(PO ₄ ) _z ], where 1≥x≥4, 1≥y≥5 and 1≥z≥>4, as solid or aqueous solutions or suspensions, diphosphoric acid [ H ₄ P ₂ O ₇ ], metaphosphoric acid [(HPO ₃ ) _n ], where n≥3, or salts thereof, phosphorus pentoxide [P ₂ O ₅ ], or mixtures of the foregoing, where M is as defined above, and

iv) an optional metal donor (D) (M) in a percentage of from about 0 wt.% to about 50 wt.% by weight of the mixture, selected from metal-containing compounds of one or more metals from the group consisting of K, Rb, Cs, Mg , Ca, Sr, Ba, transition metals (block d), in particular Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Mn, Cu, Zn, and third metals and semimetals, the fourth and fifth main groups, in particular B, Al, Ga, In, Si, Sn, Sb, Bi, and lanthanides, and selected from oxides, hydroxides, oxide hydroxides, carbonates, oxalates, formates, acetates, citrates, lactates, orthophosphates , pyrophosphates and sulfates of the aforementioned metals and mixtures thereof,

the weight fraction of the components (A)-(D) of the mixture is calculated based on the percentage of substances without the inclusion of any solvent and/or suspending agent,

b) the resulting mixture containing aqueous and/or organic solvents is dried at a temperature of less than about 400°C, and

c) the dry or dried mixture is processed at a temperature of from about 400 to about 1200°C.

[040] The preparation of a mixture of an iron compound (A) and a reducing agent (B) and an optional phosphate donor (C) and a metal donor (D) (M) in step a) of the method described herein can be achieved by dissolving, suspending and /or mixing the components in an aqueous or organic solvent or without additional solvent.

[041] The weight fraction of components (A)-(D) of the mixture specified in this document is calculated based on the percentage of substances without the inclusion of any solvent and/or suspending agent. For example, if phosphoric acid [H ₃ PO ₄ ] is introduced as a phosphate donor (C) and used as an aqueous solution, the weight fraction of H ₃ PO ₄ will be indicated without including water introduced as a solvent.

[042] The solvent and/or suspending agent may be present in a ratio of 10 to 0.1 relative to the total weight of the mixture without the inclusion of a solvent and/or suspending agent. A weight ratio of 8 to 1 is preferred, and more preferably 4 to 1. A high percentage of solvent and/or suspending agent can simplify the processing of the mixture, while a low percentage of solvent and/or suspending agent, respectively, shortens the subsequent step. fastening.

[043] When the mixture of step a) is a solution or suspension, its preparation occurs at a temperature of from about 10° C. or room temperature to the boiling point of the solution or suspension, preferably at a temperature below about 150° C., more preferably from about 20° C to about 100°C, and even more preferably from about 40°C to about 90°C. In addition, the manufacture of the solution or suspension described herein can be carried out at temperatures above the boiling point of the liquid, using a closed container at autogenous pressure of the solvent at the appropriate temperature.

[044] For the preparation of the mixture in step a), a polar solvent is preferably used, in particular a solvent with a low viscosity level and / or a low boiling point, since this leads to a simplification and significant acceleration of the subsequent fixing step, in particular when using a spray drying procedure. A suitable example of a polar solvent includes, without limitation, water, low chain length alcohols and polyols, ammonia, and mixtures thereof, with water being particularly preferred.

[045] Preferably, the Fe(III) and/or Fe(III)/Fe(II) compounds used as the iron(A) compounds in step a) are selected from the group consisting of oxides, hydroxides, oxide hydroxides, orthophosphates , pyrophosphates, metaphosphates and sulfates. Their advantage is that the anion is stable in terms of decomposition reactions and/or redox reactions during mixing and fixing. The use of anions advantageously does not result in the release of any undesirable by-products during the redox processes that occur during the heat treatment in step c). This means that a product with a more uniform particle size distribution and porosity can be obtained. The use of Fe(III) and/or Fe(III)/Fe(II) orthophosphates, pyrophosphates and metaphosphates has the further advantage that they also provide phosphate ions containing phosphorus in the oxidation step (V) to form the product . The amount of iron compound (A) in the mixture of step a) is from about 20 wt.% to about 90 wt.%, preferably from about 25 wt.% to about 85 wt.%, more preferably from about 30 wt.% to approximately 75 wt.%, while the weight percentage is calculated based on the total weight of all components i)-iv) without the inclusion of any solvent or suspending agent.

[046] Preferably, the reducing agent (B) in step a) ii) is selected from the group consisting of phosphonic acid, phosphinic acid, hypodiphosphoric acid, diphosphonic acid, and hypodiphosphonic acid, and mixtures thereof. Alternatively or as an additional measure, acid anhydrides, phosphorus trioxide, phosphorus tetroxide or a mixture thereof can be used as the reducing agent (B) of step b). The advantage of using an anhydride is that the fixing step b) carried out after step a) can be carried out relatively quickly due to the low water content of the anhydride.

[047] The amount of reducing agent (B) in the mixture made in step a) is from about 5 wt.% to about 50 wt.%, preferably from about 7.5 wt.% to about 40 wt.%, more preferably , from about 10 wt.% to about 30 wt.%, while the weight percentage is calculated based on the total weight of all components i)-iv) without the inclusion of any solvent or suspending agent.

[048] In the context of this document, the mixture of step a) may further comprise a phosphate donor (C) described herein, which introduces phosphate ions with phosphorus into the mixture in the oxidation step (V). It is expedient to add an additional phosphate donor (C) in such an amount that the phosphate ions generated by the reducing agent (B) in step c) of the heat treatment and the phosphate ions introduced by the phosphate donor (C) are present in molar amounts relative to the Fe ions and, where applicable, metal ions (M) to provide sufficient phosphate ions to form the product. The use of aqueous strongly acidic phosphoric acid solutions as phosphate donors is expedient due to good availability, ease of dosing, and very low cost. The use of an appropriate P2O5 acid anhydride has the advantage that the fixing step, which is carried out after mixing, can be carried out much faster due to the low water content. The amount of phosphate donor (C) in the mixture of step a) is from about 0 wt.% to about 50 wt.%, preferably from about 0 wt.% to about 40 wt.%, more preferably from about 0 wt.% to about 30 wt.%, while the weight percentage is calculated based on the total weight of all components i) iv) without the inclusion of any solvent or suspending agent.

[049] As described herein, the mixture of step a) may further comprise an additional metal donor (D) described herein. In a manufacturing process for producing metal-containing iron(II) compounds without water of crystallization of the general formula Fe _a M _b (PO _c ) _d , this metal donor (D) provides "M" in addition to the iron-containing metal components, if they were not provided in sufficiently due to the phosphate donor. The metal donor (D) is selected from the group consisting of oxides, hydroxides, oxide hydroxides, carbonates, oxalates, formates, acetates, citrates, lactates, orthophosphates, pyrophosphates, sulfates, and mixtures thereof. The advantage of using hydroxides, oxide hydroxides, carbonates, oxalates, formates, acetates, citrates and/or lactates is that no anion residues remain as impurities in the product of these compounds after the heat treatment in step c). The advantage of using orthophosphates and pyrophosphates is that phosphate ions are simultaneously used to form the final product. The amount of metal donor (D) in the mixture of step a) is from about 0 wt.% to about 50 wt.%, preferably from about 0 wt.% to about 40 wt.%, more preferably from about 0 wt.% to about 30 wt.%, while the weight percentage is calculated based on the total weight of all components i)-iv) without the inclusion of any solvent or suspending agent.

[050] The mixture made in step a) of the method described herein is then dried at a temperature of less than about 400° C. in a subsequent step b) if it contains aqueous and/or organic solvents, with a temperature of less than 400° C. to the temperature of the mixture to be fixed during the curing process. In this context, fixation means that water and/or other solvents are removed from the mixture to such an extent that the water and/or other solvent content is less than about 5% by weight, preferably less than about 3% by weight, and more preferably less than approximately 0.8 wt.%, while the weight percentage is calculated based on the total weight of the mixture. The degree of anchoring can be determined by thermogravimetry (TGA).

[051] Fixing the mixture in step b) can be carried out using any suitable drying process, including, but not limited to, freeze drying, supercritical drying, microwave drying, vacuum drying, convective drying, such as convective drying in air or convective drying in an inert atmosphere. gas, spray drying, spray granulation or rotary kiln drying. Preferably, the fixing of the mixture in step b) includes convective drying under an inert gas atmosphere and spray drying or spray granulation, since these keep the tendency of the product to oxidize to a low level. Spray drying is even more preferred as it is very energy efficient and ensures a uniform particle size distribution of the product. In the case of fixing using convective methods, for example in a rotary kiln, the temperature of the drying gas can reach 600°C if the fixing is carried out in an inert gas atmosphere. In this case, the temperature of the mixture to be fixed should not exceed 400°C. If the convective drying is not carried out in an inert gas atmosphere, the temperature of the drying gas does not exceed 400°C, preferably does not exceed 300°C, more preferably does not exceed 250°C, in order to reduce the oxidation of the reducing agent mixed with oxygen.

[052] According to one embodiment, fixing the mixture in step b) is carried out by evaporating the solution or suspension made herein in a hot gas stream in a spray dryer. The hot gas and product flow are directed in continuous flow or countercurrent and vaporization is achieved using at least one pressurized nozzle, a single agent nozzle, or a dual agent nozzle, or at least one rotary evaporator, or a combination thereof. Particularly preferred is the fastening in a continuous mode. Heated air, air containing burner exhaust gas, oxygen-reduced air enriched with nitrogen or inert gases, and nitrogen can preferably serve as the hot gas stream. Particularly preferred is the use of heated air and air containing exhaust gases from the burner. The heating of the hot gas stream is preferably carried out using at least one burner, hot gas generator, electric gas heater or steam heat exchangers, or combinations thereof. During evaporation, it is particularly preferred to use at least one dual-substance nozzle or rotary evaporator. Particularly preferably, the vaporization is carried out in a two-substance nozzle using compressed air, nitrogen or hot steam at a pressure of from about 1.0 to about 6.0 bar. More preferably, compressed air is used in the pressure range of about 1.5 to about 3.0 bar. Separation of the dried product stream from the process gas stream is preferably achieved using at least one cyclone or at least one filter, or any combination thereof.

[053] According to another embodiment, the consolidation of the mixture in step b) is carried out by evaporating the solution or suspension made herein in a fluidized bed in a hot gas stream made from already dried products in a spray granulator with at least one granulation zone. Evaporation of a solution or suspension according to the present invention is achieved using at least one nozzle, a single agent nozzle, a dual agent nozzle, a multisubstance nozzle, or a combination thereof. The production can be carried out in batches or continuously. Evaporation is preferably carried out in a two-substance nozzle using compressed air, nitrogen, or hot steam at a pressure of from about 1.0 to about 6.0 bar. More preferably, compressed air is used in the pressure range of about 1.5 to about 3.0 bar.

[054] According to a preferred embodiment, spray granulation is carried out in the granulation zone in a continuous mode by continuously spraying a solution or suspension and continuously removing the dried granulate from the fluidized bed. Suitable hot gas streams are heated air, heated air containing burner exhaust gas, heated oxygen-reduced air enriched with nitrogen or inert gases, and heated nitrogen. Particularly preferred is the use of heated air and heated air containing burner exhaust gases.

[055] In another preferred embodiment, the consolidation of the mixture in step b) is carried out continuously in a spray granulator with several fluidization zones, particularly preferably 2 to 5 zones. In a particularly preferred embodiment, the final fluidization zone is used to cool the product, and it is fluidized and held without spraying the solution or suspension according to the present invention with cold gas.

[056] In the spray granulation process, the necessary fluidized bed in the spray granulator is advantageously continuously created by abrasion and spray drying and provided by filters or a filter return in the device. In a particularly preferred embodiment, the granulation system also has a sieving and grinding cycle in which, on the one hand, the dry product is separated from particles that are too large and too small by sifting, and the coarse and fine particles are added back to the spray granulator as a fluidized bed by grinding. Hot gas generation in spray granulation is the same as hot gas generation in spray drying.

[057] The dried mixture made in step b) of the method described herein is then subjected to heat treatment (calcination) at a temperature of from about 400°C to about 1200°C, preferably from about 500°C to about 1100°C and more preferably from about 600°C to about 1000°C. The temperature must be chosen high enough to ensure the melting of all substances involved in the reaction. During the heat treatment in step c), among other things, the Fe(III) ions introduced into the mixture by the iron(A) compound must be reduced to Fe(II) ions.

[058] Temperature treatment of the dried mixture made in step b) is carried out batchwise or continuously in an inert or reducing atmosphere, preferably in nitrogen, inert gas, forming gas with a maximum concentration of 5 vol.% H ₂ or combinations thereof. The volume percentage of oxygen in the process gas is ideally from about 0.0% to about 1.0% by volume, preferably less than about 0.3% by volume, and more preferably less than about 0.03% by volume. The use of forming gas is particularly preferably "95/5", in other words, 95% by volume of nitrogen (N ₂ ) and 5% by volume of hydrogen (H ₂ ).

[059] In a preferred embodiment, the temperature treatment in step c) is carried out continuously in a controlled atmosphere, whereby the process gas atmosphere is directed in continuous flow with the product or in countercurrent to the product.

[060] In another preferred embodiment, the dried mixture made in step b) is then heat treated with countercurrent process gases in a rotary kiln with an attached cooling zone. Process gas is introduced from the side of the cooling zone and passed through the cooling product to prevent oxidation. Particularly preferred is the use of indirectly heated rotating drums with at least one heating zone, but preferably two to eight heating zones, which can be controlled independently. Indirect heating can occur in many different ways, including but not limited to electrical resistance heating (heating elements, heating coils), gas burners, oil burners, or induction; electrical resistance heating and gas burners are preferred.

[061] In another preferred embodiment, the rotating drum is internally provided with lift blade assemblies, preferably two to six radially extending lift blades, which improve mixing of the solids into the gas phase and promote heat transfer on the wall side. Also preferred are lift blades or assemblies with axial conveyor components which are suitable for reducing residence time in the rotating drum. Suitable rotating drums have gas-purged seals which are applied under an inert gas or reduced atmosphere to prevent oxygen intrusion. The separation of the atmosphere is advantageously carried out by means of double shuttle valves, rotary valves and/or washable propellers. Covering the product in question with a layer of inert or reducing atmosphere minimizes the entry of oxygen into the furnace.

[062] In a preferred embodiment, the heat treatment in step c) is carried out in a rotary kiln. This allows a continuous temperature treatment procedure to be carried out, which is therefore generally more cost effective than a batch procedure. The use of an indirectly heated rotary kiln is particularly advantageous because it allows precise control of the atmosphere in the product manufacturing zone.

[063] The temperature treatment in step c) can preferably be carried out in an inert gas atmosphere, in other words, the atmosphere consists of a gas or gas mixture, such as, for example, N ₂ and / or noble gases, which do not interact with the components of the mixture in an appropriate temperature range.

[064] In a preferred embodiment of the process described herein, the heat treatment in step c) is carried out in a reducing gas atmosphere. In this context, a reducing gas atmosphere means that it contains at least one reducing gas component which is suitable for reducing the components of the mixture to be treated, in particular for reducing the Fe(III) ions introduced into the mixture by the iron(A) compound to Fe ions (II). Suitable reducing gas components are CO and H ₂ . Particularly preferred is the use of a forming gas containing 5% by volume of H ₂ in N ₂ because it is neither flammable nor toxic.

[065] According to the present invention, it is particularly preferred to carry out most of the reduction of Fe(III) ions to Fe(II) ions using a reducing agent (B) and the remainder of the reduction using a reducing gas atmosphere. This can suppress both the formation of free carbon and the formation of metal phosphides.

[066] In a preferred embodiment of the method described herein, the mixture made in step a) contains Fe(III) ions in a molecular ratio to reducing agents (B) that, based on stoichiometry and assuming 100% conversion, will provide recovery from 70 % to 99%, preferably from 80% > to 98%, particularly preferably from 90% to 95% of Fe(III) ions to Fe(II) ions with a reducing agent (B). If a high percentage of reducing agents is required from a stoichiometric point of view, there is a risk of the formation of metal phosphides and/or elemental metals which make the product impure and may darken it. Using the example of phosphonic acid [H ₃ PO ₃ ] as a reducing agent with phosphorus in the oxidation step (III), this would correspond to a stoichiometric ratio of P(III) atoms in the reducing agent to Fe(III) ions from 0.35:1 to 0.495:1 with an estimated recovery of 70% to 99%.

[067] The protective paints described herein are oxidation-curing protective paints, UV-visible radiation-curing protective paints, heat-curing protective paints, or combinations thereof.

[068] The security inks described herein are particularly suitable for application by a printing process selected from the group consisting of offset printing processes, gravure printing processes, screen printing processes, rotogravure printing processes, flexographic printing processes, and inkjet printing processes. using a flex print head, onto a substrate such as those described herein, preferably selected from the group consisting of gravure printing processes, screen printing processes, rotogravure printing processes, flexographic printing processes, and flexographic inkjet printing processes. a print head, and more preferably selected from the group consisting of gravure printing processes, screen printing processes and rotogravure printing processes.

[069] Oxidation-curing protective paints are dried by oxidation in the presence of oxygen, in particular in the presence of oxygen in the atmosphere. During the curing process, oxygen combines with one or more of the ink components to solidify the ink. The process can be accelerated by the use of desiccants (also referred to in the art as catalysts, desiccants, desiccants or dessicators) such as, for example, inorganic or organic metal(s) salts, organic acid metal soaps, metal complexes and salts. complexes based on metals, optionally using heat treatment. One or more desiccants used in the oxidation-curable protective paint described herein are preferably present in an amount of from about 0.01 to about 10% by weight, more preferably in an amount of from about 0.1 to about 5% by weight, wherein the weight percentage is calculated on the basis of the total weight of the protective paint cured by oxidation. Preferably, one or more drying agents are polyvalent metal salts containing cobalt, calcium, copper, zinc, iron, zirconium, manganese, barium, zinc, strontium, lithium, vanadium and potassium as cation(s); and halides, nitrates, sulfates, carboxylates such as acetates, ethylhexanoates, octanoates and naphthenates or acetoacetonates as anion(s). More preferably, one or more drying agents are selected from the group consisting of ethylhexanoates or octanoates of manganese, cobalt, calcium, strontium, zirconium, zinc and mixtures thereof.

[070] As is generally known in the art, oxidation curable protective paints comprise one or more varnishes. The term "lacquer" is also referred to in the art as a resin, binder, or paint carrier. The oxidation-curing varnishes described herein are preferably present in the oxidation-curing protective paints described herein in an amount of from about 10 to about 90% by weight, the weight percentage being based on the total weight of the oxidation-curing protective paints. One or more varnishes for oxidation-curing protective paints described herein are preferably selected from the group consisting of polymers containing unsaturated fatty acid residues, saturated fatty acid residues, and mixtures thereof, as is generally known in the art. Preferably, one or more of the varnishes of the oxidation-curing protective paints described herein contain unsaturated fatty acid residues to provide air-drying properties. Particularly preferred oxidation-curable lacquers are resins containing unsaturated acid groups, even more preferably resins containing unsaturated carboxylic acid groups. However, resins may also contain saturated fatty acid residues. Preferably, the lacquers of the oxidation-curing protective paints described herein contain acidic groups, ie. oxidation-curing varnishes are selected from among acid-modified resins. The oxidation curing varnishes described herein may be selected from the group consisting of alkyd resins, vinyl polymers, polyurethane resins, hyperbranched resins, rosin modified maleic resins, rosin modified phenolic resins, rosin ester, rosin ester modified coumaronoindene resin, alkyd resin modified with coumaronoindene resin, rosin/phenol resin modified with alkyd resin, rosin ester modified with alkyd resin, rosin/phenol resin modified with acrylic compounds, rosin ester modified with acrylic compounds, rosin/phenol resin modified urethane, urethane modified rosin ester, urethane modified alkyd resin, epoxy modified rosin/phenolic resin, epoxy modified alkyd resin, terpene resins, nitrocellulose resins, polyolefins, polyamides, acrylic resins; and combinations or mixtures thereof. Polymers and resins are used interchangeably herein.

[071] Compounds of saturated and unsaturated fatty acids can be obtained from natural and/or artificial sources. Natural sources include animal sources and/or plant sources. Animal sources may include animal fat, milk fat, fish oil, pork fat, liver oils, tuna oil, sperm whale oil and/or tall oil and waxes. Vegetable sources may include waxes and/or oils, such as oils of vegetable origin and/or oils of non-vegetable origin. Examples of vegetable oils include, but are not limited to, bitter gourd, borage, marigold, canola, castor oil, Chinese tree oil, coconut oil, conifer seed oil, corn seed oil, cottonseed oil, dehydrated castor oil, linseed oil, grape seed oil , Jacaranda mimosifolia seeds, linseed oil, palm oil, palm kernel oil, peanut oil, pomegranate seed oil, rapeseed oil, safflower oil, trichosanthus serpentine oil, soybean (bean) oil, sunflower oil, logwood oil, tung oil and wheat germ oil. Artificial sources include synthetic waxes (such as microcrystalline and/or paraffin wax), petroleum tailings, and/or products obtained by chemical or biochemical synthesis methods. Suitable fatty acids also include (Z)-hexadan-9-enoic [palmitoleic] acid (C ₁₆ H ₃₀ O ₂ ), (Z)-octadecan-9-enoic [oleic] acid (C ₁₈ H ₃₄ O ₂ ), ( 9Z,11E,13E)-octadeca-9,11,13-trienoic [α-eleosteoric] acid (С ₁₈ H ₃₀ O ₂ ), lycanic acid, (9Z,12Z)-octadeca-9,12-dienoic [linoic] acid ₍ C _{18 H 32 O 2} ) )-octadeca-9-enoic [ricinoleic] acid (C ₁₈ H ₃₄ O ₃ ), (Z)-docosan-13-enoic [erucic] acid (C ₂₂ H ₄₂ O ₃ ), (Z)-eicosan-9- enoic [gadoleic] acid (C ₂₀ H ₃₈ O ₂ ), (7Z, 10Z,13Z,16Z, 19Z)-proof-7,10,13,16,19-pentaenoic [cloupanoic] acid and mixtures thereof.

[072] Suitable fatty acids are C2-C24 carboxylic acids containing ethylene conjugated or non-conjugated double bonds, such as myristoleic, palmitoleic, arachidonic, erucic, gadoleic, clupanodonic, oleic, ricinoleic, linoleic, linolenic, lycanic, lowsic acid and eleostearic acids or mixtures thereof. Such fatty acids are typically used as mixtures of fatty acids derived from natural or synthetic oils.

[073] The oxidation-curable protective paints described herein may additionally contain one or more antioxidants, such as those known to those skilled in the art. Suitable antioxidants include, without limitation, alkylphenols, hindered alkylphenols, alkylthiomethylphenols, eugenol, secondary amines, thioether, phosphites, phosphonites, dithiocarbamates, gallates, malonates, propionates, acetates and other esters, carboxamides, hydroquinones, ascorbic acid, triazines, benzyl compounds, as well as tocopherols and terpene analogues. Such antioxidants are commercially available, for example, from sources disclosed in WO 02/100960. Heterically hindered alkylphenols are phenols containing at least one or two alkyl groups in ortho orientation with respect to the phenolic hydroxyl. One, preferably both, alkyl groups in ortho orientation with respect to the phenolic hydroxyl are preferably secondary or tertiary alkyl, most preferably tertiary alkyl, especially t-butyl, t-amyl or 1,1,3,3-tetramethylbutyl. Preferred antioxidants are hindered alkylphenols and especially 2-t-butylhydroquinone, 2,5-di-t-butylhydroquinone, 2-t-butyl-p-cresol and 2,6-di-t-butyl-p-cresol. If present, one or more antioxidants are present in an amount of from about 0.05 to about 3 wt.%, with the weight percentage calculated based on the total weight of the oxidatively cured protective paint.

[074] The oxidation-curing protective paints described herein may additionally contain one or more waxes, preferably selected from the group consisting of synthetic waxes, petroleum waxes, and natural waxes. Preferably, one or more waxes are selected from the group consisting of microcrystalline waxes, paraffin waxes, polyethylene waxes, fluorocarbon waxes, polytetrafluoroethylene waxes, Fischer-Tropsch waxes, silicone fluids, beeswaxes, candelilla waxes, montan waxes, carnauba waxes, and mixtures thereof. If present, one or more waxes are preferably present in an amount of from about 0.1 to about 15% by weight, the weight percentage being based on the total weight of the oxidatively cured protective paint.

[075] The oxidation curable protective paints described herein may further comprise one or more fillers and/or thinners, preferably selected from the group consisting of carbon fibres, talcs, micas (e.g. muscovites), wollastonites, calcined clays, porcelain clays, kaolins, carbonates (eg calcium carbonate, sodium aluminum carbonate), silicates (eg magnesium silicate, aluminum silicate), sulfates (eg magnesium sulfate, barium sulfate), titanates (eg potassium titanate), aluminum oxide hydrates, silicon dioxide, colloidal silicon dioxide, montmorillonites, graphites, anatase, rutiles, bentonites, vermiculites, zinc white, zinc sulfides, drill flour, quartz flour, natural fibers, synthetic fibers and combinations thereof. If present, one or more fillers or diluents are preferably present in an amount of from about 0.1 to about 40 wt.%, with the weight percentage calculated based on the total weight of the oxidatively cured protective paint.

[076] In an embodiment, the oxidation-curable security inks described herein are oxidation-curable gravure security inks, wherein said oxidative-curable gravure security inks comprise one or more of the desiccants described herein, one or more varnishes described herein, and optional additives or ingredients described herein.

[077] In an embodiment, the oxidation-curable protective inks described herein are oxidation-curable offset printing inks, wherein said oxidation-curable offset protective inks comprise one or more of the desiccants described herein, one or more varnishes described in this document, and optional additives or ingredients described in this document.

[078] The machine-readable security features described herein can be obtained by a gravure printing process (also referred to in the art as copper plate printing and embossed steel stamp printing) that can be applied to a substrate with a sufficiently large amount of machine-readable material. in order to enable its detection and detection. Intaglio printing processes are among the printing methods used in particular in the field of security documents. The gravure printing process is known to be the most consistent and high quality printing process for producing fine tapering lines and is therefore the preferred printing technique for obtaining a fine pattern in the area of security documents, in particular banknotes and stamps. In particular, one of the hallmarks of the gravure printing process is that the thickness of the ink layer transferred to the substrate can be varied from a few micrometers to several tens of micrometers by using respectively shallow or deep engravings on the gravure printing apparatus. As mentioned above, the thickness of the printed intaglio security feature layer thus allows a large enough amount of machine-readable material to be obtained on the substrate to be detected and detected.

[079] Oxidation-curable protective inks for offset printing are known in the art to require high viscosity. Typically, protective inks suitable for oxidation curing offset printing processes have viscosities ranging from about 2.5 to about 25 Pa*s at 40° C. and 1000 s ^-1 ; the viscosities were measured using a Haake Roto-Visco RV1 rheometer with a 2 cm 0.5° cone geometry.

[080] Oxidative gravure security inks are known in the art to require high viscosity. Typically, protective inks suitable for oxidation curing gravure processes have viscosities ranging from about 3 to about 60 Pa⋅s at 40°C and 1000 s ^-1 using a Haake Roto-Visco RV1 rheometer, The rheometer uses a cone-plate geometry with a diameter of 20 mm and a geometry of 0.5°.

[081] The oxidatively curable gravure security inks described herein may further comprise one or more surfactants, in particular hydrophilic macromolecular surfactants such as those described, for example, in EP 0340163 B1. The role of the optional surfactants is to help remove excess ink present on the impression cylinder just before said impression cylinder contacts the substrate. This ink removal process is part of a high-speed, industrial gravure printing process and is carried out using a cloth or paper roll ("calico") or a polymer cylinder to remove excess ink and a water-based cleaning solution ("wash solution"). In this case, optional surfactants are used to emulsify the excess paint in the cleaning solution. Said surfactants may be non-ionic, anionic or cationic, as well as zwitterionic. In the case of hydrophilic macromolecular surfactants, the functional groups are, for example, carboxyl or sulfonic acid groups, hydroxyl groups, ether groups or primary, secondary, tertiary or quaternary amino groups. The acidic groups can be neutralized with amines, alkanolamines, or preferably inorganic bases or combinations thereof. Primary, secondary and tertiary amino groups can be neutralized with inorganic or organic acids such as sulfonic acids, formic acid, acetic acid, trifluoroacetic acid and others. Particularly preferred are anionic macromolecular surfactants (AMS) such as those described in EP 2014729 AL

[082] UV-visible curable protective paints consist of protective paints that can be cured by UV-visible radiation. The UV-VIS curable protective paints described herein contain from about 0.1% to about 20% by weight of one or more photoinitiators, and preferably from about 1% to about 15% by weight. , whereby the weight percentage is calculated from the total weight of the UV/VIS curable protective paint.

[083] Preferably, the UV-VIS curable protective paints described herein comprise one or more UV-curable monomer and oligomer compounds selected from the group consisting of radical- curable compounds; and cationically curable compounds. The protective paints described herein may be a hybrid system and contain a mixture of one or more cationically curable compounds and one or more radically curable compounds. Cationically curable compounds are cured by cationic mechanisms, typically involving radiation activation of one or more photoinitiators that release cationic species such as acids, which in turn initiate curing so as to react and/or crosslink the monomers and/ or oligomers to allow the protective paint to cure in this way. Radical curable compounds are cured by free radical mechanisms, typically involving radiation activation of one or more photoinitiators, thereby generating radicals which in turn initiate polymerization to cause the protective paint to cure in this way.

[084] Preferably, the UV-visible protective paint described herein contains one or more oligomers (also referred to in the art as prepolymers) selected from the group consisting of oligomeric (meth)acrylates, vinyl ethers, propenyl ethers, cyclic ethers such as epoxides, oxetanes, tetrahydrofurans, lactones, cyclic thioethers, vinyl and propenyl thioethers, hydroxyl-containing compounds and mixtures thereof. More preferably, the binder of the UV-visible protective paint described herein is derived from oligomers selected from the group consisting of oligomeric (meth)acrylates, vinyl ethers, propenyl ethers, cyclic ethers, such as epoxides, oxetanes, tetrahydrofurans, lactones and mixtures thereof. Representative examples of epoxides include, without limitation, glycidyl ethers, β-methylglycidyl ethers of aliphatic or cycloaliphatic diols or polyols, glycidyl ethers of diphenols and polyphenols, glycidyl ethers of polyhydric phenols, phenol-formaldehyde novolac 1,4-butanediol diglycidyl ethers, resorcinol diglycidyl ethers , glycidylalkyl ethers, glycidyl ethers containing copolymers of acrylic acid esters (for example, styrene-glycidyl methacrylate or methyl methacrylate-glycidyl acrylate), polyfunctional liquid and solid novolac resins based on glycidyl ethers, polyglycidyl ethers and poly(β-methylglycidyl) esters, poly(N-glycidyl) compounds, poly(S-glycidyl) compounds, epoxy resins in which glycidyl groups or β-methylglycidyl groups are bonded to different types of heteroatoms, glycidyl esters of carboxylic acids and polycarboxylic acids from, limonene monoxide, epoxidized soybean oil, bisphenol-A and bisphenol-F epoxy resins. Examples of suitable epoxides are disclosed in EP 2125713 B1. Suitable examples of aromatic, aliphatic, or cycloaliphatic vinyl ethers include, without limitation, compounds containing at least one, preferably at least two, vinyl ether groups per molecule. Examples of vinyl ethers include, but are not limited to, triethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, 4-hydroxybutyl vinyl ether, propylene carbonate propenyl ether, dodecyl vinyl ether, t-butyl vinyl ether, t-amyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, ethylene glycol monovinyl ether , Butanediol Monovinyl Ether, Hexanediol Monovinyl Ether, 1,4-Cyclohexanedimethanol Monovinyl Ether, Diethylene Glycol Monovinyl Ether, Ethylene Glycol Divinyl Ether, Ethylene Glycol Butyl Vinyl Ether, Butane-1,4-Diol Divinyl Ether, Hexanediol Divinyl Ether, Diethylene Glycol Divinyl Ether, Triethylene Glycol Divinyl Ether , triethylene glycol methyl vinyl ether, tetraethylene glycol divinyl ether, pluriol-E-200 divinyl ether, polytetrahydrofuran divinyl ether-290, trimethylolpropane trivinyl ether, dipropylene glycol divinyl ether, octadecyl vinyl ether, methyl ester (4-cyclohexyl methyl lenoxyethene)-glutaric acid; and (4-butoxyethene)-isophthalic acid ester. Examples of hydroxy-containing compounds include, without limitation, polyester polyols such as, for example, polycaprolactones or polyether adipate polyols, glycols and polyether polyols, castor oil, hydroxy-functional vinyl and acrylic resins, cellulose esters such as cellulose acetate butyrate, and phenoxy resins. Further examples of suitable cationically curable compounds are disclosed in EP 2125713 B1 and EP 0119425 B1.

[085] According to one embodiment of the present invention, the UV-VIS curable protective paints described herein comprise one or more radical curable oligomeric compounds selected from (meth)acrylates, preferably selected from the group consisting of epoxy(meth)acrylates, (meth)acrylate-modified oils, polyester(meth)acrylates, aliphatic or aromatic urethane(meth)acrylates, silicone (meth)acrylates, amino(meth)acrylates, acrylic (meth)acrylates, and mixtures thereof. The term "(meth)acrylate" in the context of the present invention refers to acrylate as well as the corresponding methacrylate. The components of the UV-VIS curable security paints described herein can be prepared with additional vinyl esters and/or monomeric acrylates such as, for example, trimethylol propane triacrylate (TMPTA), pentaerythritol triacrylate (PTA), tripropylene glycol diacrylate ( TPGDA), dipropylene glycol diacrylate, hexanediol diacrylate (HDDA) and their polyethoxylated equivalents such as, for example, polyethoxylated trimethylol propane triacrylate, polyethoxylated pentaerythritol triacrylate, polyethoxylated tripropylene glycol diacrylate, polyethoxylated dipropylene glycol diacrylate and polyethoxylated hexanediol diacrylate.

[086] Alternatively, the UV-VIS curable protective paint described herein is a hybrid paint and can be made from a mixture of radical curable compounds and cationically curable compounds such as those described herein. .

[087] As mentioned above, curing under the influence of radiation in the UV and visible region of the monomer, oligomer requires the presence of one or more photoinitiators and which can be influenced in various ways. As mentioned herein and known to those skilled in the art, the UV-VIS curable protective paint described herein to be cured and cured on a substrate comprises one or more photoinitiators as described herein, optionally with one or more photosensitizers, wherein said one or more photoinitiators and optional one or more photosensitizers are selected according to its/their absorption spectrum(s) in correlation with the emission spectrum of the radiation source. Depending on the degree of transmission of electromagnetic radiation through the substrate, the hardening of the protective paint can be achieved by increasing the exposure time. However, depending on the substrate material, the exposure time is limited by the substrate material and its sensitivity to the heat generated by the radiation source.

[088] Depending on the monomers, oligomers, or prepolymers used in the UV-VIS curable protective paint described herein, various photoinitiators can be used. Suitable examples of free radical photoinitiators are known to those skilled in the art and include, without limitation, acetophenones, benzophenones, benzyl dimethyl ketals, alpha-aminoketones, alpha-hydroxy ketones, phosphine oxides, and phosphine oxide derivatives, as well as mixtures of two or more of these. Suitable examples of cationic photoinitiators are known to those skilled in the art and include, without limitation, onium salts such as organic iodonium salts (eg, diaryloiodonium salts), oxonium (eg, triaryloxonium salts), and sulfonium salts (eg, triarylsulfonium salts), as well as mixtures of the two or more of them. Other examples of photoinitiators used can be found in standard scientific textbooks such as "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", Volume III, "Photoinitiators for Free Radical Cationic and Anionic Polymerization)", 2nd edition, J. V. Crivello & K. Dietliker, edited by G. Bradley and published in 1998 by John Wiley & Sons in association with SITA Technology Limited. In order to achieve effective curing, it may also be advantageous to include the sensitizer together with one or more photoinitiators. Representative examples of suitable photosensitizers include, but are not limited to, isopropylthioxanthone (ITX), 1-chloro-2-propoxythioxanthone (CPTX), 2-chlorothioxanthone (CTX), and 2,4-diethylthioxanthone (DETX), as well as mixtures of two or more of these.

[089] The UV-visible radiation-cured security ink described herein is preferably a UV-visible radiation-cured offset printing ink, a UV-visible radiation-cured protective ink for gravure, UV-VIS curable screen printing ink UV-VIS curable screen printing ink flexographic UV-VIS curable security ink rotogravure or curing Inkjet UV/VIS Inkjet Security Ink, More Preferably UV/VIS Curable UV/VIS Inkjet Security Ink screen printing ink UV/VIS curable screen printing ink UV/VIS curable flexographic printing ink inkjet ink using a flex print head.

[090] According to an embodiment, the UV-visible radiation-curable protective inks described herein are UV-visible radiation-curable protective inks for offset printing, wherein said UV-visible radiation-curable protective inks are visible range, offset printing inks comprise one or more of the photoinitiators described herein, one or more UV-curable monomer and oligomer compounds described herein, and optional additives or ingredients described in this document.

[091] According to an embodiment, the UV-visible radiation-curable security inks described herein are UV-visible radiation-curable protective inks for gravure printing, said UV-visible radiation-curable and visible range, gravure security inks comprise one or more of the photoinitiators described herein, one or more UV-curable monomer and oligomer compounds described herein, and optional additives or ingredients described in this document.

[092] UV-visible protective inks for offset printing are known in the art to require high viscosity. Generally, security inks suitable for UV and visible curing printing processes have viscosities ranging from about 2.5 to about 25 Pa*s at 40°C and 1000 s ^-1 ; the viscosities were measured using a Haake Roto-Visco RV1 rheometer with a 2 cm 0.5° cone geometry.

[093] UV-VIS curable protective inks for gravure printing are known in the art to require high viscosity. Generally, security inks suitable for gravure printing processes typically have viscosities in the range of about 3 to about 60 Pa*s at 40°C and 1000 s ^-1 using a Haake Roto-Visco RV1 rheometer, with the rotary rheometer using the geometry "cone-plate" with a diameter of 20 mm and with a geometry of 0.5 °.

[094] According to an embodiment, the UV-visible radiation-curable protective inks described herein are UV-visible radiation-curable screen printing inks, said UV-visible radiation-curable and screen printing inks contain one or more of the photoinitiators described herein, one or more UV-curable monomer and oligomer compounds described herein, and optional additives or ingredients described in this document.

[095] Screen printing (also referred to in the art as silk screen printing) is a stencil process in which ink is transferred to a surface through a stencil supported by a fine fabric mesh of silk, synthetic fibers, or metal threads tautly stretched over a frame. The mesh pores are blocked in non-image areas and left open in image areas, the image carrier being called screen mesh. Screen printing can be flat or rotary. During printing, ink enters the frame, which is poured onto the stencil screen, and then a squeegee is passed through it, thus pushing the ink through the open pores of the stencil screen. At the same time, the printable surface is kept in contact with the screen and the ink is transferred onto it. Screen printing is further described, for example, in The Printing ink manual, RH Leach and RJ Pierce, Springer Edition, 5th edition, pp. ^58-62 and in Printing Technology, JM Adams and PA Dolin, Delmar Thomson Learning, 5th ^edition , pp. 293-328.

[096] UV-VIS curable screen printing inks are known in the art to require low viscosity. Typically, protective inks suitable for screen printing processes have viscosities ranging from about 0.05 to about 5 Pa⋅s at 25°C using a Brookfield machine (DV-I Prime model, small sample adapter, spindle SC4-21 at 50 rpm).

[097] According to an embodiment, the UV-visible radiation-curable barrier inks described herein are UV-visible radiation-curable protective inks for flexographic printing, wherein said UV-visible radiation-curable barrier inks are visible region, flexographic security inks comprise one or more of the photoinitiators described herein, one or more UV-curable monomer and oligomer compounds described herein, and optional additives or ingredients described in this document.

[098] Flexographic printing methods preferably use a doctor blade unit, preferably a doctor blade, an anilox roller, and a plate cylinder. The anilox roll advantageously has small cells, the volume and/or density of which determines the extent to which the protective varnish is applied. The squeegee chamber is located opposite the anilox roller, fills the cells and at the same time removes excess protective varnish. The anilox roller transfers the ink to the plate cylinder, which ultimately transfers the ink to the substrate. Form cylinders can be made of polymeric or elastomeric materials. Resins are mainly used as a photopolymer in printing plates and sometimes as a seamless coating on a roll. Photopolymer printing plates are made from photosensitive polymers that cure when exposed to ultraviolet (UV) light. Photopolymer printing plates are cut to the required size and placed in a UV light exposure unit. One side of the printing plate is completely exposed to UV light to cause solidification or curing of the base of the printing plate. Then the printing plate is turned over, the reverse side of the blank is set over the uncured side, and the printing plate is further exposed to UV light. This ensures that the printing plate hardens in the areas of the image. The printing plate is then processed to remove the uncured photopolymer from the non-image areas, which reduces the surface of the printing plate in these non-image areas. After processing, the printing plate is dried and exposed to an additional dose of UV light to cure the entire printing plate. The production of plate cylinders for flexography is described in Printing Technology, J. M. Adams and P.A. Dolin, Delmar Thomson Learning, 5th edition, pp. 359-360.

[099] UV-VIS curable security inks for flexographic printing are known in the art to require low viscosity. Typically, security inks suitable for flexographic printing processes have a viscosity in the range of about 0.01 to about 1 Pa⋅s at 25°C and 1000 s ^-1 using a DHR-2 rotational viscometer from TA Instruments (having the geometry "cone-plate" and a diameter of 40 mm).

[0100] In an embodiment, the UV-VIS curable security inks described herein are UV-VIS-curable rotogravure security inks, wherein said UV-Curable and visible region, rotogravure security inks comprise one or more of the photoinitiators described herein, one or more of the UV-curable monomer and oligomer compounds described herein, and optional additives or ingredients, described in this document.

[0101] As will be known to those skilled in the art, the term "rotogravure printing" refers to the printing process, which is described, for example, in "Handbook of print media", Helmut Kipphan, Springer Edition, page 48. Rotogravure printing is a printing process in which image elements are engraved on the surface of a cylinder. Areas without an image are at a constant baseline. Before printing, the entire printing form (non-printable and printable elements) is covered with ink and filled with ink. The ink is removed from the non-image area with a sponge or knife before printing so that the ink remains only in the cells. The image is transferred from the cells to the substrate under pressure, typically in the range of 2-4 bar, and adhesive forces between the substrate and the ink. The term "rotogravure" does not cover other gravure printing processes (also referred to in the art as engraved steel die embossing processes or engraved copper plate printing processes), which are based, for example, on different types of inks.

[0102] UV-VIS curable security inks for rotogravure printing are known in the art to have low viscosity. Typically, security inks suitable for rotogravure printing processes have viscosities ranging from about 0.01 to about 0.5 Pa*s at 25°C and 1000 s ^-1 using a DHR-2 rotational viscometer from TA Instruments. (having a "cone-plate" geometry and a diameter of 40 mm).

[0103] According to an embodiment, the UV-VIS curable security inks described herein are UV-VIS-curable security inks for inkjet printing using a flex print head, wherein said UV-VIS curable inkjet security inks using a flex print head contain one or more of the photoinitiators described herein, one or more UV-curable compounds that are monomers and oligomers described in this document, and optional additives or ingredients described in this document.

[0104] Inkjet printing using a flexural print head is inkjet printing using a flexural print head configuration. Typically, flexural transducers include a housing or substrate, a flexible membrane with a hole made in it, and a drive. The backing defines a reservoir for retaining a supply of fluid material, and the flexible membrane has a peripheral edge supported by the backing. The actuator can be either piezoelectric (i.e., it includes a piezoelectric material that deforms when an electrical voltage is applied) or thermally activated, as described in US 8226213, for example. Thus, when the actuator material is deformed, the flexible membrane deflects, causing ejection of some amount of fluid material from the reservoir through the opening. The flexural printhead configurations are described in US 5,828,394, which discloses a liquid ejector that includes a single wall including a thin, elastic membrane having an opening defining a nozzle, and elements responsive to electrical signals to deflect the membrane to eject liquid droplets from the nozzle. . Flexural print head configurations are described in US 6,394,363, where the disclosed configurations utilize, for example, excitation of surface layers, including nozzles, that are positioned over a single surface layer in an addressable manner, forming a fluid projection array capable of operating at high frequencies with a wide range of fluids. . Pan-tilt print head configurations are also described in US 9,517,622, which describes a liquid drop forming device comprising a film element vibrated to eject liquid held in a liquid holding unit in which a nozzle is formed in the film element. In addition, a vibrating unit is provided for vibrating the film element; and a drive unit for selectively applying the ejection waveform and the mixing waveform to the vibrating unit. The flexural printhead configurations are also described in US 8226213, which describes a method of actuating a thermal flex actuator in which an active beam is coupled to a passive beam. The method includes passing an electric current through the active beam to cause thermoelastic expansion of the active beam relative to the passive beam and bending of the drive.

[0105] UV-VIS curable inkjet security inks using a flex print head are known in the art to have very low viscosity. Typically, security inks suitable for inkjet printing processes using a flexural printhead have a viscosity of less than about 100 mPa.s when measured at 25°C and 1000 s ^-1 using a DHR-2 rotational viscometer from TA Instruments. with cone-plate geometry and 40 mm diameter.

[0106] Heat-curing protective paints consist of protective paints that are dried by exposure to hot air, infrared radiation, or a combination thereof. Heat-curing protective inks typically consist of about 10% to about 90% by weight solids that remain on the print substrate, about 10% to about 90% by weight of one or more solvents, which evaporate as a result of fixation, wherein the one or more solvents are selected from the group consisting of organic solvents, water, and mixtures thereof.

[0107] Preferably, the organic solvents described herein are selected from the group consisting of alcohols (such as ethanol), ketones (such as methyl ethyl ketone), esters (such as ethyl acetate or propyl acetate), glycol ethers (such as DOWANOL DPM), glycol ether esters (such as butyl glycol acetate), and mixtures thereof.

[0108] In one embodiment, the heat-curing protective paints described herein consist of water-based heat-curing protective paints containing one or more resins selected from the group consisting of polyester resins, resins based on polyethers, polyurethane resins (e.g. carboxylated polyurethane resins), polyurethane alkyd resins, polyurethane acrylate resins, polyacrylate resins, polyether urethane resins, styrene acrylate resins, polyvinyl alcohol resins, poly(ethylene glycol) resins, polyvinylpyrrolidone resins, polyethyleneimine resins, modified starches, complex cellulose ethers or ethers (such as cellulose acetate and carboxymethyl cellulose), copolymers and mixtures thereof.

[0109] In an embodiment, the heat-curing protective paints described herein consist of solvent-based heat-curing protective paints containing one or more resins selected from the group consisting of nitrocelluloses, methylcelluloses, ethylcelluloses, cellulose acetates , polyvinyl butyrals, polyurethanes, polyacrylates, polyamides, polyesters, polyvinyl acetates, rosin-modified phenolic resins, phenolic resins, maleic resins, styrene-acrylic resins, polyketone resins, and mixtures thereof.

[O110] As mentioned above, dual-curing or dual-curing security inks can be used to print the machine-readable security feature described herein, where these security inks combine two curing or curing mechanisms.

[0111] Examples of dual-cure or dual-cure security inks include oxidation curing mechanisms and UV-visible radiation curing mechanisms, such as, for example, gravure security inks.

[0112] Examples of dual-cure or dual-cure security inks include oxidation curing mechanisms and heat curing mechanisms such as, for example, screen printing security inks, rotogravure security printing inks, and CV inkjet security inks. print head.

[0113] Examples of dual-curing or dual-curing security inks include UV-visible radiation curing mechanisms and heat curing mechanisms such as, for example, screen printing security inks and rotogravure printing inks. Typically, such dual-curing or dual-curing protective paints are similar to UV-visible protective paints, but will include a volatile portion consisting of water and/or one or more organic solvents. These volatile components are first evaporated using hot air and/or IR desiccants and then UV/VIS curing completes the curing process.

[0114] The protective paints described herein may additionally contain one or more fillers or thinners, preferably selected from the group consisting of carbon fibers, talc, mica (muscovite), wollastonites, calcined clays, china clays, kaolins, carbonates ( e.g. calcium carbonate, sodium aluminum carbonate), silicates (e.g. magnesium silicate, aluminum silicate), sulfates (e.g. magnesium sulfate, barium sulfate), titanates (e.g. potassium titanate), alumina hydrates, silica, colloidal silica , montmorillonites, graphites, anatase, rutiles, bentonites, vermiculites, zinc white, zinc sulfides, drill flour, quartz flour, natural fibers, synthetic fibers and combinations thereof. If present, one or more fillers or diluents are preferably present in an amount of from about 0.1 to about 40 wt.%, with the weight percentage calculated based on the total weight of the protective paint.

[0115] The protective paints described herein may additionally contain one or more colorants (pigments or dyes).

[0116] The security paints described herein may additionally contain one or more IR absorbers known in the art. The role of said IR absorbers is, for example, to slightly change the reflectance profile of the security feature in order to fully comply with the specifications of the detection system.

The security inks described herein may further contain one or more luminescent compounds, for example, to provide a security feature with increased security against forgery.

The protective paint described herein may additionally contain one or more marker substances or markers.

[0117] The protective paint described herein may further comprise one or more additives, wherein said one or more additives include, without limitation, compounds and materials that are used to adjust the physical, rheological, and chemical parameters of the protective paint, such as consistency ( e.g. anti-settling agents and plasticizers), foaming properties (e.g. antifoams and deaerators), lubricating properties (waxes), UV resistance (photo stabilizers), adhesion properties, surface properties (wetting agents, oleophobic and hydrophobic agents), fixing/curing agents (curing accelerators, sensitizers, crosslinkers), etc. The additives described herein may be present in the protective paints described herein in amounts and forms known in the art, including in the form of so-called nanomaterials, in which at least one of the sizes of the additives is in the range 1-1000 nm.

[0118] The present invention further provides methods for producing the protective paints described herein, and protective paints obtained by such methods. The security paints described herein can be prepared by dispersing or mixing one or more of the IR absorbing materials described herein and all other ingredients, thereby forming liquid or paste paints. If the protective paints described herein are UV-VIS curable protective paints, one or more photoinitiators may be added to the formulation either during the dispersion or mixing step of all other ingredients, or may be added in a subsequent step. , i.e. after the formation of liquid or pasty paints. Varnishes, binders, monomers, oligomers, resins, and additives are generally selected from those known in the art and as described above, and depend on the printing process used to apply the security ink described herein to the substrate described in this document.

[0119] The security inks described herein are applied to the substrate described herein to obtain a machine-readable security feature through a printing process, preferably selected from the group consisting of offset printing processes, gravure printing processes, screen printing processes, rotary printing processes. gravure printing processes, flexographic printing processes and inkjet printing processes using a flexographic printhead, more preferably selected from the group consisting of gravure printing processes, screen printing processes, rotogravure printing processes, flexographic printing processes and inkjet printing processes using longitudinal a curved print head, and even more preferably selected from the group consisting of gravure printing processes, screen printing processes and rotogravure printing processes.

[0120] The present invention further provides methods for obtaining the machine-readable security features described herein, and machine-readable security features obtained by these methods. The method includes the step a) applying, through a printing process, preferably selected from the group consisting of gravure printing, screen printing, flexographic printing, rotogravure printing and inkjet printing using a flex printhead, a security ink as described herein onto a substrate described in this document.

[0121] After the printing step is performed, step b) of fixing and/or curing the security ink in the presence of UV and visible radiation and/or air or heat to form the machine-readable security feature described herein on the substrate is carried out, wherein said step fastening is carried out after step a).

[0122] The present invention further provides machine-readable security features made from the security ink described herein on the substrate described herein.

[0123] The substrates described herein are preferably selected from the group consisting of paper or other fibrous materials (including woven and nonwoven fibrous materials) such as cellulose, materials containing paper, glasses, metals, ceramics, plastics and polymers, metallized plastics or polymers, composite materials and mixtures or combinations of two or more of them. Typical paper, paper-like, or other fibrous materials are made from a wide variety of fibers, including, without limitation, manila hemp, cotton, flax, wood pulp, and mixtures thereof. As is well known to those skilled in the art, cotton fiber and cotton/linen fiber blends are preferred for banknotes, while wood pulp is generally used for non-banknote security documents. Typical examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), including biaxially oriented polypropylene (BOPP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene-2,6-naphthoate) (PEN) and polyvinyl chlorides (PVC). The substrate can also be olefin fibers spun with high velocity air flow, such as those sold under the trademark Tyvek®. Typical examples of metallized plastics or polymers include the plastics or polymer materials described herein above, on the surface of which metal is continuously or discontinuously located. Typical examples of metals include, without limitation, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), their alloys, and combinations of two or more of the above metals. The plating of the plastic or polymeric materials described herein above can be carried out using an electrodeposition process, a high vacuum coating process, or a sputtering process. Representative examples of composite materials include, but are not limited to, multilayer structures or laminates of paper and at least one plastic or polymer material such as those described herein above, and plastic and/or polymer fibers incorporated into a paper-like or fibrous material such as described above in this document. Of course, the substrate may contain additional additives known to those skilled in the art, such as fillers, sizing agents, brighteners, processing aids, reinforcing agents or wet strength agents, etc.

[0124] The present invention further provides security documents comprising a substrate as described herein and a machine-readable security feature as described herein, or security documents containing more than one of the machine-readable security features as described herein. Security documents include, without limitation, valuable documents and valuable commercial items. A typical example of documents of value includes, without limitation, banknotes, legal documents, tickets, cheques, vouchers, revenue and tax stamps, agreements, etc., identity documents such as passports, identity cards, visas, driver's licenses, bank cards , credit cards, transaction cards, access documents or cards, entrance tickets, public transport tickets or public transport entitlements, etc. The term "high value commercial item" refers to packaging material, in particular for the pharmaceutical, cosmetic, electronic or food industries, which can be protected against counterfeiting and/or illicit reproduction in order to guarantee the authenticity of the contents of the package, such as genuine medicines. Examples of these packaging materials include, but are not limited to, labels such as product authentication labels, tamper-evident labels and seals. Preferably, the security document described herein is selected from the group consisting of banknotes, identity documents, title documents, driver's licenses, credit cards, access cards, public transport authorization documents. , vouchers and secure product labels. Alternatively, the security features described herein may be applied to a secondary substrate such as, for example, a security thread, security strip, foil, decal, window, or label, and then transferred to the security document in a separate step.

[0125] In order to further enhance the security and protection against forgery and illegal reproduction of security documents, the substrate described herein may contain printed, coated or laser marked or laser-perforated marks, watermarks, security threads, fibers, confetti , luminescent compounds, windows, foils, decals, primers, and combinations of two or more of these, provided that these potential additional elements do not adversely affect the NIR absorption properties of the machine-readable security feature.

[0126] In order to increase durability by improving soil resistance or chemical resistance and cleanliness and thus the service life of security documents or to change their aesthetic appearance (for example, optical gloss), over the machine-readable security features or security document described herein, one or more protective layers may be applied. If present, the one or more protective layers are generally made of protective varnishes, which may be clear or lightly colored or tinted, and may be more or less glossy. Protective varnishes can be radiation-curable compositions, heat-curable compositions, or any combination thereof. Preferably, one or more protective layers are made of radiation curable materials. More preferably, UV-visible curable compositions.

[0127] The machine-readable security features described herein can be applied directly to a substrate on which they must remain permanently (as, for example, in the banknote industry). Alternatively, for manufacturing purposes, the machine-readable security feature can also be applied to a temporary substrate from which the machine-readable security feature is subsequently removed. Therefore, after the security ink described herein has hardened/cured to produce a machine-readable security feature, the temporary substrate can be removed from the machine-readable security feature.

[0128] Alternatively, in another embodiment, an adhesive layer may be provided on the machine-readable security feature, or may be provided on a substrate containing said machine-readable security feature, said adhesive layer being provided on the side of the substrate opposite the side on which the machine-readable security feature is provided. the security feature, or on the same side as the machine-readable security feature and over the machine-readable security feature. Therefore, an adhesive layer can be applied to a machine-readable security feature or to a substrate, said adhesive layer being applied after the fixing or curing step has been completed. Such a product can be attached to all types of documents or other products or objects without printing or other processes involving machines and mechanisms and rather high labor costs. Alternatively, the substrate described herein containing the machine-readable security feature described herein may be in the form of a transfer foil that can be applied to a document or article in a separate transfer step. To this end, the substrate is provided with a release coating on which a machine-readable security feature is produced, as described herein. One or more adhesive layers can be applied over the thus obtained machine-readable security feature.

[0129] Also described herein are substrates, security documents, decorative elements, and objects containing more than one, i. two, three, four, etc., of the machine-readable security feature described herein. Also described herein are articles, in particular security documents, decorative elements and objects containing the machine-readable security feature described herein.

[0130] As mentioned herein above, the machine-readable security features described herein can be used to protect and authenticate a security document or decorative elements.

[0131] Representative examples of decorative elements or objects include, without limitation, luxury goods, cosmetic packaging, automotive parts, electronic/electrical appliances, furniture, and nail art.

[0132] Security documents include, without limitation, documents of value and valuable commercial goods. Typical examples of documents of value include, without limitation, banknotes, legal documents, tickets, cheques, vouchers, revenue and duty stamps, agreements, etc., identification documents such as passports, identity cards, visas, driver's licenses, bank cards , credit cards, transaction cards, access documents or cards, entrance tickets, public transport tickets, high school diploma or academic titles, etc., preferably banknotes, identity documents, documents granting the right to possession, driver's licenses and credit cards. The term "high value commercial item" refers to packaging materials, in particular for cosmetics, nutraceuticals, pharmaceuticals, spirits, tobacco, beverages or foods, electrical/electronic products, fabrics or jewelry, i.e. products that must be protected from counterfeiting and/or illegal reproduction, in order to guarantee the authenticity of the contents of the package, such as genuine medicines. Examples of these packaging materials include, but are not limited to, labels such as product authentication labels, tamper-evident labels and seals. It should be noted that the disclosed substrates, valuable documents, and valuable commercial items are provided by way of example only, without limiting the scope of the present invention.

[0133] The machine-readable security features comprising one or more of the IR absorbing materials described herein may consist of a pattern, image, indicia, logo, text, number, or code (such as a barcode or QR code). ).

[0134] According to one embodiment, the substrates, security documents, decorative elements, and objects described herein comprise a first portion consisting of a machine-readable security feature described herein and made of a security ink containing one or more IR-absorbing radiation from the materials described herein, and a second portion consisting of a security feature made from an ink containing one or more compounds absorbing in a different region of the electromagnetic spectrum (UV or visible) to form a combined security feature. The first and second portions of the combined security feature described herein may be adjacent, may overlap, or be spaced apart. When the second section is made of an ink containing one or more compounds absorbing in the visible region of the electromagnetic spectrum, the complex security feature can be implemented in such a way that the first and second sections create an image, both parts being made of inks that match in color in the visible spectrum .

[0135] According to one embodiment of the substrate, the security documents, decorative elements, and objects described herein comprise a combined security feature, said combined security feature comprising a first portion consisting of a machine-readable security feature described herein and made of a security ink containing one or more IR absorbing materials described herein, and a second portion consisting of a security feature made of a machine-readable magnetic ink containing one or more magnetic compounds to form said combined security feature. The first and second portions of the combined security feature described herein may be adjacent, may overlap, or be spaced apart. Preferably, the substrates, security documents, decorative elements, and objects described herein comprise a combined security feature in which the second portion is made of a machine-readable magnetic ink containing magnetic pigment particles containing a magnetic core (preferably made of nickel, cobalt, iron, and iron-containing alloys and oxides) and surrounded by one or more additional layers made of one or more materials selected from the group consisting of organic materials and the group of inorganic materials, such as those described, for example, in documents WO 2010/115986 A2 and WO 2016 /005158 A1. The organic materials described herein are preferably selected from the group consisting of polyacrylates, polystyrenes, parylenes, alkoxysilanes, and mixtures thereof. The inorganic materials described herein are preferably selected from the group consisting of metals (preferably selected from the group consisting of silver, aluminum and gold), metal oxides (preferably selected from the group consisting of MgO and ZnO, Al ₂ O ₃ , Y ₂ O ₃ , Ln ₂ O ₃ (where Ln is a lanthanide), SiO ₂ , TiO ₂ , ZrO ₂ , CeO ₂ and mixtures thereof) and metal sulfides (preferably selected from the group consisting of ZnS; CaS and mixtures thereof) . Especially preferred are the substrates, security documents, decorative elements and objects described herein, containing a combined security feature in which the second area is made of machine-readable magnetic ink containing magnetic pigment particles containing the magnetic core described herein, and surrounded by one or more additional layers made of one or more materials selected from the group consisting of organic materials and the group of inorganic materials described herein, while the first section and the second section are made of paints that match in color in the visible spectrum.

[0136] The present invention further provides methods for authenticating a security document, including the steps of a) providing a security document described herein and containing a machine-readable security feature made from the ink described herein; b) illuminating the machine-readable security feature at at least two wavelengths, wherein one of said at least two wavelengths is in the visible range (400-700 nm) and the other of said at least two wavelengths is in the near-IR -range (780 nm 1400 nm), c) detecting the optical characteristics of the machine-readable security feature by perceiving light reflected by the specified machine-readable security feature at at least two wavelengths, wherein one of the specified at least two wavelengths is in the visible range ( 400-700 nm), and the other of these at least two wavelengths is in the near-IR range (780-1400 nm); and d) determining the authenticity of the security document based on the detected optical characteristics of the machine-readable security feature.

[0137] Authentication of the machine-readable security feature described herein and made from the ink described herein can be performed using an authentication device comprising one or more light sources, one or more detectors, an analog-to-digital converter, and a processor. The machine-readable security feature is simultaneously or sequentially illuminated by one or more light sources; one or more detectors detect light reflected by said machine-readable security feature and output an electrical signal proportional to the intensity of the light; and the analog-to-digital converter converts these signals into digital information, which is compared by the processor with the reference information stored in the database. The authenticator then issues a positive authenticity signal (ie, the machine-readable security feature is genuine) or a negative signal (ie, the machine-readable security feature is fake).

[0138] According to one embodiment, the authentication device comprises a first source (such as an LED in the visible spectrum) emitting at a first wavelength in the visible range (400-700 nm), a second source (such as an LED in the near infrared spectrum), emitting at a second wavelength in the near infrared (780-1400 nm) and a broadband detector (such as a photomultiplier). The first and second sources emit at a certain time interval, which allows the broadband detector to separately output signals corresponding to emissions in the visible and near-IR regions, respectively. These two signals can be compared separately (visible signal with visible reference signal and near-IR signal with reference signal in the near-IR region). Alternatively, the two signals can be converted to a difference (or ratio) value, and said difference (or ratio) value can be compared to a reference difference (or ratio) value stored in a database.

[0139] According to another embodiment of the detection unit, and in order to increase the operating speed, the specified detector may contain two detectors specially matched to the emission wavelength of the first and second sources (for example, a Si photodiode for the visible range and an InGaAs photodiode for the near infrared range ). The first and second sources emit simultaneously, the two detectors simultaneously sense the light reflected by the security feature, and the two signals (or their difference or ratio) are compared with the reference signals stored in the database.

[0140] According to another embodiment, and in order to improve security against forgery, the authentication device comprises a source emitting at multiple (i.e., two, three, etc.) wavelengths in the visible range and at multiple (i.e., two, three, etc.) wavelengths in the near-IR range. The sources are sequentially activated and the light reflected by the machine-readable security feature is detected by a broadband detector (eg, photomultiplier). The signals corresponding to the multiple emission wavelengths are then processed into a full spectrum which is compared with a reference spectrum stored in a database.

[0141] According to another embodiment, and in order to increase security against forgery, as well as increase operating speed, the authentication device includes a broadband, continuous light source (for example, a tungsten, tungsten and halogen or xenon lamp), a collimation unit, a diffraction grating and a detector matrix. The diffraction grating is located in the optical path after the machine readable security feature, with the light reflected by said machine readable security feature being focused onto the grating by a collimation unit (usually consisting of a series of lenses and/or an adjustable slot). The detector array consists of a plurality of detector elements, each of which is sensitive to a specific wavelength. Thus, signals corresponding to light intensities at multiple wavelengths are acquired simultaneously, processed as a full spectrum, and compared with a reference spectrum in a database.

[0142] In another embodiment, and for the purpose of obtaining a two-dimensional image of the machine-readable security feature described herein, the detector may be a CCD or CMOS sensor. In this case, the detectable wavelength range is from about 400 nm to about 1100 nm (which is the upper detection limit of silicon sensors). The machine-readable security feature is illuminated sequentially at at least two wavelengths, one of the at least two wavelengths being in the visible range (400-700 nm) and the other in the near-IR range available for CCD or CMOS. -detector (780 nm 1100 nm). Alternatively, a CCD or CMOS sensor can be equipped with a filter layer so that the individual pixels of the sensor are sensitive to different and limited regions of the visible (400-700nm) and near-IR (780-1100nm) regions. In this case, it is possible to simultaneously obtain two-dimensional images of a machine-readable security feature at at least two wavelengths, one in the visible range (400-700 nm) and the other in the near-IR range accessible to a CCD or CMOS detector (780 nm-1100 nm). The 2D images are then compared with reference images stored in a database.

[0143] Optionally, the authentication device may include one or more light-diffusing elements (e.g., a condenser), one or more lens assemblies (e.g., focusing or collimating lenses), one or more slots (adjustable or not), one or more reflective elements (such as mirrors, especially translucent mirrors), one or more filters (such as polarizing filters), and one or more optical fiber elements.

[0144] The specialist can make a number of changes within the essence of the present invention in the specific embodiments described above. Such modifications are covered by the present invention.

[0145] In addition, all documents referenced throughout this specification are hereby incorporated herein in their entirety as if they were fully set forth therein.

EXAMPLES

[0146] The present invention will be further described in more detail with reference to non-limiting examples. The examples below disclose in more detail the preparation and use of security inks for printing a machine-readable security feature, said security inks independently comprising an IR-absorbing material.

[0147] Received four types of protective paints, which were applied to the substrate:

i) oxidation curable gravure security inks (examples E1, E2 and comparative example C1),

ii) UV-VIS curable screen printing inks (Examples E3, E4 and Comparative C2),

iii) heat curable rotogravure security inks (examples E5, E6 and comparative example C3), and

iv) Heat curable screen printing inks (Examples E7, E8 and Comparative Example C4),

while E1, E3, E5 and E7 contained iron(II) orthophosphate without water of crystallization with a graftonite structure (IR-A 1),

while E2, E4, E6 and E8 contained potassium iron(II) orthophosphate without water of crystallization (IR-A 2), and

while C1, C2, C3 and C4 contained commercial iron(II) orthophosphate containing water (IR-A 3).

Structure and composition of IR-absorbing materials IR-A1 and IR-A2

Production of IR-absorbing material IR-A 1

[0148] Suspension containing 21.75 kg of iron(III) oxide-hydroxide [FeO(OH) or Fe ₂ O ₃ ⋅H ₂ O], 12.15 kg of 98% phosphonic acid (H ₃ PO ₃ ), 10, 3 kg of iron(III) phosphate dihydrate [FePO ₄ ⋅2H ₂ O] and 140 kg of water, spray-granulated. The granules thus obtained were heat treated in a rotary kiln for about 90 minutes under a forming gas atmosphere (5 vol/vol % H ₂ in N ₂ and at 750° C.). An almost colorless product was obtained. The product crystallized in the graftonite structure and was identified using PDF card 00-49-1087. An X-ray diffraction pattern (XRD) of the IR-absorbing material IR-A 1 is shown in FIG. 1A. The product was ground so that the d50 value (average particle size) was below 3 µm using a jet mill (AFG 100 Oppposed Jet Mill, Hosokawa Alpine). The d10, d50 and d90 values presented in Table 1 were obtained by the measurement method described below in distilled water.

Preparation of IR absorbing material IR-A 2

[0149] Suspension containing 11.80 kg of iron(III) oxide-hydroxide [FeO(OH) or Fe ₂ O ₃ ⋅H ₂ O], 10.70 kg of 98% phosphonic acid (H ₃ PO ₃ ), 24, 8 kg iron(III) phosphate dihydrate [FePO ₄ ⋅2 H ₂ O], 29.8 kg 50% lye [KOH], 1.0 kg 75% phosphoric acid [H ₃ PO ₄ ] and 110 kg water, spray granulated . The granulates thus obtained were subjected to heat treatment in a rotary kiln for approximately three hours under a forming gas atmosphere (5 vol/vol % H ₂ in N ₂ and at 650° C.). A pale light green product was obtained. An X-ray diffraction pattern (XRD) of the IR-absorbing material IR-A 2 is shown in FIG. 1B. The product was identified using PDF card 01-076-4615. The product was ground so that the d50 value (average particle size) was below 3 µm using a jet mill (AFG 100 Oppposed Jet Mill, Hosokawa Alpine). The d10, d50 and d90 values shown in Table 1 were obtained by the measurement method described below in ethyl acetate.

X-ray diffractometry (XRD)

[0150] As mentioned above, X-ray diffraction (XRD) measurements were made for two IR absorbing materials IR-A 1 and IR-A 2. For these X-ray diffraction (XRD) measurements, a D8 Advance A25 type diffractometer (Bruker) was used. and CuKα irradiation. The products and their crystal structures were identified based on the corresponding reference diffraction patterns (Powder Diffraction Files; PDF) from the ICDD (International Center for Diffraction Data), formerly JCPDS (Joint Committee on Powder Diffraction Standards).

Particle Size Distribution

[0151] PSD measurements were made in either water or ethyl acetate using laser diffractometry (Cilas 1090) according to ISO 13320. The d10, d50 and d90 values were extracted from the particle size distribution curves and are presented in Table 1. The Frauenhofer model was used , and the calculations were performed using SizeExpert version 9.40. The values of d10, d50 and d90 given in Table 1 correspond to d(v.10), d(v.50) and d(v.90), respectively.

Analytical measurement of the presence of the absence of water of crystallization (Fig. 2)

[0152] DSC measurements were independently performed for IR-A 1 and IR-A 3 using a differential scanning calorimeter (DSC131 Evo, SETARAM) under nitrogen with approximately 25 mg of the respective IR absorbing material. For each IR-absorbing material, two complete measurement cycles were carried out. For each cycle, the temperature was increased from about 25°C to about 385°C at a rate of about 10°C/min, then the temperature was again reduced to about 25°C at the same rate.

[0153] FIGS. 2A and 2B show the resulting DSC curves for both cycles (FIG. 2A: IR-A 3 and FIG. 2B: IR-A 1). As shown in FIG. 2A with a strong endothermic peak (negative peak) peaking at approximately 150° C., water of crystallization was recovered from IR-A 3 during the first cycle (solid black curve corresponding to the cycle in which the temperature was raised, and black dotted curve corresponding to the cycle in which the temperature was lowered). During the second cycle (grey continuous curve corresponding to the cycle in which the temperature was increased and gray dotted curve corresponding to the cycle in which the temperature was lowered), no negative peak was observed. Accordingly, IR-A3 consisted of a material containing water of crystallization.

[0154] As shown in FIG. 2 In the absence of any endothermic peak and overlapping curves of the first and second cycles (solid black curve corresponds to the first cycle in which the temperature was increased, black dotted curve corresponds to the first cycle in which the temperature was lowered, gray continuous curve corresponds to the second cycle in which the temperature was increased , dotted gray curve corresponding to the second cycle in which the temperature was lowered), IR-A 1 consisted of material without water of crystallization.

A. Oxidation-fixed gravure security inks (Examples E1, E2 and Comparative Example C1)

A.1. Obtaining protective paints (E1, E2 and C1)

[0155] The ingredients of Table 2A were independently thoroughly mixed by hand with a spatula to obtain oxidation curable gravure security inks E1, E2 and C1. The pasty mixtures thus obtained were ground independently in a Buhler SDY 200 three-roll mill in four passes (two passes opened at 6 bar, one pass closed at 12 bar and the last pass opened at 6 bar). Viscosity was independently measured with a Haake Roto Visco RV1 rotary rheometer using a 20 mm cone-plate geometry with a 0.5° geometry, at 1000 s ^-1 and 40°C.

A.2. Obtaining printed security features (E1, E2 and C1)

[0156] In order to imitate a printed gravure security feature made from the oxidation-fixable gravure security inks described in Table 2A, these security inks were independently applied to a piece of fiduciary money paper (BNP paper from Louisenthal, 100 g/ m ² , 4.5 cm×23.3 cm) using the Prüfbau MZ-E multi-purpose ink and paper print test bench. The size of the printed pattern was 20.2 cm×3.9 cm. The amount of applied protective inks (wet) was 8±0.2 g/m ² . After the coating/printing step, the security features were secured for seven days at room temperature in the dark.

A.3 Results (E1, E2 and C1)

[0157] The effect of the IR absorbing material present in oxidatively curable gravure security inks on the visible color of the security features was evaluated by measuring the L*a*b* values of the printed samples according to CIELAB (1976), where L* indicated the brightness of the printed sample, a* and b* were color coordinates in Cartesian 2-dimensional space (a*=color value on the red/green axis and b*=color value on the blue/yellow axis). L*a*b* values were measured using a DC 45 spectrophotometer from Datacolor (measurement geometry: 45/0°; spectrum analyzer: patented dual-channel holographic grating. 256-photodiode linear arrays used for both control channels and reference channels ; light source: common bandpass LED backlight). Three separate points were measured for each security feature. The average of the three measurements of L*a*b* values is presented in Table 2B.

[0158] The reflectance spectra of samples printed with oxidatively cured E1, E2, and C1 gravure security inks were measured with a DC45 from Datacolor over a range of 400 nm to 1100 nm. 100% reflectance was measured using the internal standard of the device. The reflectance values (in %) at the selected wavelengths are presented in Table 2C, and the entire spectrum (400-1100 nm) is shown in FIG. 3 (E1 - solid line; E2 - dotted line and E3 - dashed/dotted line).

[0159] As shown in Table 2C, the printed gravure security feature made from the comparative oxidation-curable gravure ink C1 exhibited a low reflectance of about 400 nm to about 1100 nm. As shown in Table 2D, the printed gravure security feature made of the comparative oxidation-fixing gravure security ink C1 showed almost no difference between the maximum reflectance in the visible range and the minimum reflectance (i.e., maximum absorption) in the near IR range. The reflectance values and profile shown make it impossible to detect said security feature (i.e., machine-readable characteristics) by standard detectors, such as those equipped with high-speed note sorting machines, since such detectors rely on the difference in reflectance at selected wavelengths in the visible and near infrared ranges. In addition, the L*a*b* values of the printed gravure security feature made of the comparative oxidation-curable gravure security ink C1 correspond to a dark green color, which makes it extremely difficult to obtain pure light colors in the visible range while still sufficiently strong absorption in the near IR range.

[0160] In contrast to the gravure printing security feature made of the comparative gravure printing oxidation-fixing security ink C1, and as shown in Tables 2C and 2D, the gravure printing security feature made of the gravure printing oxidation-fixing security inks according to the present invention (E1 and E2), showed a significant difference in reflectance between the visible and near infrared ranges, which allows you to easily and reliably detect these security features at high speed. The printed gravure security feature made of the oxidation-fixable gravure security ink of the present invention E1 was different from the security feature made of the printed gravure security feature made of the oxidation-fixable gravure security ink of the present invention E2, their corresponding reflection coefficient profile in the near-IR range. In particular, the minimum reflectance occurred at 1000 nm for a printed gravure security feature made from the oxidation curable gravure security ink according to the present invention E1, while the minimum reflectance occurred at 850 nm for a printed gravure security feature. made of the oxidation curable gravure ink according to the present invention E2. The L*a*b* values of an intaglio printing security feature made of an oxidation-curable gravure security ink according to the present invention E1 correspond to a light beige color, and the values of an intaglio printing security feature made of an oxidative-curable security ink for gravure according to the present invention E2 correspond to light green. Accordingly, the printed gravure security feature made from the oxidation-curable gravure security inks of the present invention (E1 and E2) exhibited clear and bright color in the visible range, combined with sufficiently strong absorption in the near-IR range.

B. UV-VIS Curable Screen Printing Security Inks (Examples E3, E4 and Comparative Example C2)

IN 1. Obtaining protective paints (E3, E4 and C2)

[0161] The paint binder ingredients described in Table 3A were mixed and dispersed at room temperature using Dispermat (LC220-12) for ten minutes at 1500 rpm.

[0162] 200 g of IR absorbing material (IR-A1, IR-A2 and IR-A3, respectively) were independently added to 800 g of the ink binder described in Table 3A and dispersed for ten minutes at 1500 rpm, to independently obtain one kg of the UV-visible curing E3, E4 and C2 screen printing inks described in Table 3B. The viscosities shown in Table 3B were measured on nine grams of UV-VIS curable E3, E4 and C2 screen printing inks at 25°C on a Brookfield machine (model "DV-I Prime", small sample adapter). , spindle SC4-21 at 50 rpm).

Table 3A

B.2 Obtaining printed security features (E3, E4 and C2)

[0163] In order to obtain a printed screen-printing security feature made of UV-VIS-curable screen-printing security inks of Table 3B, these security inks were independently applied by hand to a piece of fiduciary money making paper (BNP paper from Louisenthal, 100 g/m ² , 14.5 cm x 17.5 cm) using a 90T screen (230 mesh). The size of the printed pattern was 6 cm x 10 cm. After the printing step, the security features were cured by independently subjecting the printed security features to UV curing for about two seconds using Phoseon's UV LED lamp (FireFlex type 50 x 75 mm). , 395 nm, ⁸ W/cm2).

B.3 Results (E3, E4 and C2)

[0164] The effect of the IR absorbing material present in UV-VIS curable screen printing security inks on the visible color of the security features was evaluated by measuring the L*a*b* values of the printed samples according to CIELAB (1976 ) as described above. Three separate points were measured for each security feature. The average of the three measurements of L*a*b* values is presented in Table 3C.

[0165] The reflectance spectra of samples printed with E3, E4 and C2 UV-VIS curable screen printing inks were measured with a DC45 from Datacolor from 400 nm to 1100 nm. 100% reflectance was measured using the internal standard of the device. The reflectance values (in %) at the selected wavelengths are presented in Table 3D.

[0166] As shown in Table 3D, a printed screen-printable security feature made from a comparative UV-VIS-curable screen-printing security ink C2 exhibited a low reflectance of about 400 nm to about 1100 nm. As shown in Table 3E, the printed screen-printed security feature made from the comparative UV-visible screen-printed security ink C2 showed no difference between the maximum visible reflectance and the minimum near-IR reflectance. range. The reflectance values and profile shown make it impossible to detect said security feature (i.e., machine-readable characteristics) by standard detectors, such as those equipped with high-speed note sorting machines, since such detectors rely on the difference in reflectance at selected wavelengths in the visible and near infrared ranges. In addition, the L*a*b* values of a printed screen-printing security feature made from a comparative UV-visible screen-printing security ink C2 correspond to a dark green color, which makes it extremely difficult to obtain pure light colors. in the visible range with simultaneous sufficiently strong absorption in the near-IR range.

[0167] In contrast to the screen printed security feature made of the comparative UV-VIS curable screen printing ink C2, and as shown in Table 3D, the screen printed security feature made of exposed to UV and visible radiation of the screen printing security inks of the present invention (E3 and E4), showed a significant difference in reflectance between the visible and near infrared ranges, which allows these security features to be easily and reliably detected at high speed. A printed screen-printing security feature made from a UV-VIS curable screen-printing security ink according to the present invention E3 was different from a security feature made from a printed screen-printing security feature made from a UV-curable screen-printing security ink and the visible area of the screen printing ink according to the present invention E4, their respective reflectance profile in the near infrared range. In particular, the minimum reflectance occurred at 1000 nm for a printed screen-printing security feature made from the UV-VIS curable screen-printing security ink according to the present invention E3, while the minimum reflectance occurred at 850 nm for a printed screen printing security feature made from a UV-VIS curable screen printing security ink according to the present invention E4. The L*a*b* values of a printed screen-printing security feature made from a UV-VIS-curable screen-printing security ink according to the present invention E3 correspond to a light beige color, and the values of a printed screen-printing security feature, made from UV-visible screen-printing security ink according to the present invention E4 correspond to a light green color. Accordingly, the printed screen-printing security feature made from the UV-visible radiation-curable screen-printing security inks of the present invention (E3 and E4) exhibited clear and bright color in the visible range, combined with sufficiently strong near-near absorption. IR range.

C. Heat-fixable rotogravure security inks (Examples E5, E6 and Comparative Example C3)

C.1. Obtaining protective paints (E5, E6, C3)

[0168] The paint binder ingredients described in Table 4A were mixed and dispersed at room temperature using Dispermat (LC220-12) for ten minutes at 500 rpm.

[0169] 150 g of IR absorbing material (IR-A1, IR-A2 and IR-A3, respectively) were independently added to 850 g of the ink binder described in Table 4A and dispersed for ten minutes at 1200 rpm and for one minute at 1550 rpm to independently produce one kg of the E5, E6 and C3 heat-fixable rotogravure security inks described in Table 4B. The viscosities at 25°C and 1000 ^s Table 4B, heat-curing rotogravure security inks E5, E6, and C3 were determined using a TA Instruments DHR-2 rotational viscometer (cone-plate geometry, 40 mm diameter).

C.2 Obtaining printed security features E5, E6, C3)

[0170] In order to imitate the printed rotogravure security feature printed with the heat-fixing rotogravure security inks of Table 4B, these security inks were independently manually applied to a piece of fiduciary money paper (BNP paper from Louisenthal, 100 g/m ² , 14.5 cm×17.5 cm) using a No. 2 bar manual coater. The size of the printed pattern was 10 cm×12 cm. After the coating/printing step, the security features were dried for one minute with a hot air dryer at a temperature of approximately 50°C.

C3 Results (E5, E6, C3)

[0171] The effect of the IR absorbing material present in heat-curable rotogravure security inks on the visible color of the security features was evaluated by measuring the L*a*b* values of the printed samples according to CIELAB (1976) as described above. Three separate points were measured for each security feature. The average of the three measurements of L*a*b* values is presented in Table 4C.

[0172] The reflectance spectra of samples printed with E5, Eb, and C3 heat-curable rotogravure security inks were measured with a DC45 from Datacolor over a range of 400 nm to 1100 nm. 100% reflectance was measured using the internal standard of the device. The reflectance values (in %) at the selected wavelengths are presented in Table 4D.

[0173] As shown in Table 4D, a printed rotogravure security feature made from a comparative C3 heat-fixable rotogravure security ink exhibited a low reflectance of about 400 nm to about 1100 nm. As shown in Table 4E, a printed rotogravure security feature made from a comparative C3 heat-fixable rotogravure security ink showed no difference between the maximum reflectance in the visible range and the minimum reflectance in the near-IR range. The reflectance values and profile shown make it impossible to detect said security feature (i.e., machine-readable characteristics) by standard detectors, such as those equipped with high-speed note sorting machines, since such detectors rely on the difference in reflectance at selected wavelengths in the visible and near infrared ranges. In addition, the L*a*b* values of a printed rotogravure security feature made from a comparative C3 heat-fixable rotogravure security ink correspond to green, which makes it extremely difficult to obtain pure light colors in the visible range while simultaneously sufficiently strong absorption in the near-IR range.

[0174] In contrast to the printed rotogravure security feature made of the comparative heat-fixing rotogravure security ink C3, and as shown in Table 4D, the rotogravure printed security feature made of heat-setting of the rotogravure security inks of the present invention (E5 and E6) showed a significant difference in reflectance between the visible and near-IR ranges, which allows these security features to be easily and reliably detected at high speed. A printed rotogravure security feature made of a heat-set rotogravure security ink according to the present invention E5 was different from a security feature made of a printed rotogravure security feature made of a heat-set rotogravure security ink of the present invention. gravure according to the present invention E6, their respective reflectance profile in the near infrared range. In particular, the minimum reflectance occurred at 1000 nm for a printed rotogravure security feature made from the comparative heat-curable rotogravure security ink of the present invention E5, while the minimum reflectance occurred at 850 nm for a printed A rotogravure security feature made of a heat-curable rotogravure security ink E6. The L*a*b* values of a printed rotogravure security feature made from the heat-curing rotogravure security inks of the present invention (E5 and Eb) are the values of uncolored samples. Accordingly, the printed rotogravure security feature made of the heat-curing rotogravure security inks of the present invention (E5 and E6) exhibited clear and bright color in the visible range, combined with sufficiently strong absorption in the near-IR range. .

Claims (35)

1. A security ink for printing a machine-readable security feature, said security ink comprising one or more IR absorbing materials selected from the group consisting of iron(II) orthophosphates without water of crystallization of the general formula Fe ₃ (PO ₄ ) ₂ with the crystal structure of graphtonite, metal-containing iron(II) orthophosphates without water of crystallization, metal-containing iron(II) phosphonates without water of crystallization, metal-containing iron(II) pyrophosphates without water of crystallization, metal-containing iron(II) metaphosphates without water of crystallization of the general formula Fe _a M _b (PO _c ) _d , where a is a number from 1 to 5, b is a number from >0 to 5, c is a number from 2.5 to 5, d is a number from 0.5 to 3, and M is one or more metals selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, transition metals (block d ) selected from Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Mn, Cu, Zn, Co, Ni, Ag, Au, metals and semimetals of the third, fourth and fifth main groups selected from B, Al, Ga, In, Si, Sn, Sb, Bi and lanthanides, and their mixtures wherein said protective paint is an oxidation-curing protective paint containing from 0.01 to 10% by weight of one or more desiccants, the weight percentage being calculated from the total weight of the oxidation-curing protective paint, or a UV-VIS curable protective paint containing from 0.1 to 20% by weight of one or more photoinitiators, the weight percentage being calculated from the total weight of the UV-VIS curable protective paint, or a heat-curing protective paint containing from 10 to 90% by weight of one or more solvents selected from the group consisting of organic solvents, water and mixtures thereof, the weight percentage being calculated based on the total weight of the heat-curing protective paint , or their combination. 2. The security ink according to claim 1, wherein the oxidation-curable security ink is an oxidation-curable offset-printing barrier ink or an oxidative-curable gravure barrier ink, preferably an oxidative-curable gravure barrier ink. 3. The security ink according to claim 1, wherein the UV-visible radiation-cured security ink is a UV-visible radiation-cured offset printing ink, a UV-visible radiation-cured protective ink for gravure, UV-VIS curable screen printing ink UV-VIS curable screen printing ink flexographic UV-VIS-cured security ink rotogravure or curing security ink inkjet-cured security ink using a flex print head, preferably UV-visible curable gravure ink UV-visible curable security ink screen printing ink UV-VIS curable flexo UV-VIS-curable security ink Rotogravure or UV-VIS-curable security inkjet ink using a flex print head. 4. The security ink of claim 1, wherein the heat-set security ink is a screen-printing heat-set security ink, a flexographic heat-set security ink, a rotogravure heat-set security ink, or a rotogravure heat-set security ink. under the influence of heat, a protective ink for inkjet printing using a flex print head. 5. A protective paint according to any one of the preceding claims, wherein the one or more IR absorbing materials are Fe _a M _b (PO _c ) _d , where M is potassium (K), magnesium (Mg) and zinc (Zn) or a combination thereof, preferably KFePO ₄ , K(Fe _0.75 Zn _0.25 )PO ₄ or K(Fe _0.75 Mg _0.25 )PO ₄ . 6. A protective paint according to any one of the preceding claims, wherein the average particle size (d50) of each of the one or more IR absorbing materials is 0.01 to 50 µm, preferably 0.1 to 20 µm, and more preferably 1 to 10 µm. 7. A protective paint according to any one of the preceding claims, wherein one or more IR absorbing materials are present in an amount of 5 to 60% by weight, the wt% being calculated from the total amount of the protective paint. 8. A protective paint according to any one of the preceding claims, wherein one or more IR absorbing materials are obtained by a method comprising the following steps, in which: a) prepare a mixture containing i) Iron (A) compounds selected from Fe(III) compounds, Fe(III)/Fe(II) compounds and mixtures thereof in a percentage of 20 to 90% by weight of the mixture selected from the group consisting of oxides , hydroxides, oxide hydroxides, carbonates, carboxylates such as oxalates, formates, acetates, citrates, lactates, orthophosphates, phosphonates, metaphosphonates, pyrophosphates, sulfates and mixtures of the foregoing, ii) reducing agents (B) in a percentage of 5 to 50% by weight of the mixture selected from the group consisting of phosphonic acid H ₃ PO ₃ , phosphorus trioxide P ₂ O ₃ , phosphinic acid H ₃ PO ₂ , phosphorus tetroxide P ₂ O ₄ , hypodiphosphoric acid H ₄ P ₂ 0 ₆ , diphosphoric acid H ₄ P ₂ O ₅ , hypodiphosphonic acid H ₄ P ₂ O ₄ , Fe salts and M salts of the aforementioned acids and mixtures of the foregoing as solids, aqueous solutions or suspensions , iii) an optional phosphate donor (C) in a percentage of 0 to 50 wt.% by weight of the mixture, selected from phosphoric acid H ₃ PO ₄ as an aqueous solution, metal phosphate M _x (PO ₄ ) _z or hydrogen phosphate metal M _x HY(PO ₄ ) _z , where 1≥x≥4, 1≥y≥5 and 1≥z≥4, as solid or aqueous solutions or suspensions, diphosphoric acid H ₄ P ₂ O ₇ , metaphosphoric acid (HPO ₃ ) _n where n≥3, or their salts, phosphorus pentoxide P ₂ O ₅ or mixtures of the foregoing, where M is as defined above, and iv) an optional donor (D) metal (M) in a percentage of 0 to 50 wt.% by weight of the mixture, selected from metal-containing compounds of one or more metals from the group consisting of K, Rb, Cs, Mg, Ca, Sr, Ba, transition metals (block d), in particular Sc, Y, La, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Mn, Cu, Zn, and metals and semimetals of the third, fourth and fifth main groups , in particular B, Al, Ga, In, Si, Sn, Sb, Bi, and lanthanides, and selected from oxides, hydroxides, oxide hydroxides, carbonates, oxalates, formates, acetates, citrates, lactates, orthophosphates, pyrophosphates and sulfates of the aforementioned metals and their mixtures, while the weight fraction of components (A)-(D) of the mixture is calculated based on the percentage of substances without the inclusion of any solvent and/or suspending agent, b) the resulting mixture containing aqueous and/or organic solvents is dried at a temperature of less than 400°C, and c) dry or dried mixture is treated at a temperature of from 400 to 1200°C. 9. Machine-readable security feature made of protective paint according to any one of paragraphs. 1-8. 10. Security document containing a machine-readable security feature according to clause 9. 11. A security document according to claim 10, where the machine-readable security feature according to claim 9 consists of a first section and contains a second section consisting of a security feature made of ink containing one or more compounds that absorb in another region of the electromagnetic spectrum (UV or visible), or consisting of a security feature made of a machine-readable magnetic ink containing one or more magnetic compounds, preferably the first section and the second section are made of inks that match in color in the visible spectrum. 12. A method for obtaining a machine-readable security feature, characterized in that the method includes step a) applying by a printing process selected from the group consisting of offset printing, gravure printing, screen printing, flexographic printing, rotogravure printing and inkjet printing using longitudinal bending print head, protective ink according to any one of paragraphs. 1-8 on the substrate. 13. The method according to claim 12, characterized in that the method further comprises the step b) fixing and/or curing the protective paint in the presence of UV and visible radiation and/or air or heat to form a security feature on the substrate, wherein said step fastening is carried out after step a). 14. The method according to claim 12 or 13, characterized in that the substrate is selected from the group consisting of paper or other fibrous materials, materials containing paper, glasses, metals, ceramics, plastics and polymers, metallized plastics or metallized polymers, composite materials and mixtures or combinations thereof. 15. A method for authenticating a document to be protected, characterized in that the method includes steps in which a) provide a security document according to claim 10 or 11 containing a machine-readable security feature made from ink according to any one of claims. 1-8; b) illuminating the machine-readable security feature at at least two wavelengths, wherein one of said at least two wavelengths is in the visible range and the other of said at least two wavelengths is in the near-IR range; c) detecting optical characteristics of the machine-readable security feature by sensing light reflected by said machine-readable security feature at at least two wavelengths, wherein one of said at least two wavelengths is in the visible range and the other of said at least two wavelengths waves is in the near infrared range; and d) determine the authenticity of the document to be protected by detecting the optical characteristics of the machine-readable security feature.

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