EA045420B1

EA045420B1 - RADIATION CURABLE GRAVE PRINTING INKS

Info

Publication number: EA045420B1
Application number: EA202290392
Authority: EA
Inventors: Жан-Даниэль Шпиттелер; Патрик МАГНИН; Каролин Боннефой; Лиана Аннунзиата; Себастьен Голлут
Original assignee: Сикпа Холдинг Са
Priority date: 2019-07-30
Filing date: 2020-07-24
Publication date: 2023-11-24

Description

The present invention relates to the field of secure documents and their protection from forgery and illegal reproduction. In particular, the present invention relates to the field of intaglio printing methods for printing security documents.

Prerequisites for creating the invention

With the continuous improvement in the quality of color photocopies and printed works, and in an attempt to protect protected documents from forgery, falsification or illegal reproduction, it has become common practice to include various security features in these documents. Such security documents may be banknotes, valuable documents or cards, transport tickets or cards, tax stamps and product labels that do not have reproducible effects. Typical examples of security agents include security threads, windows, fibers, confetti, foils, decals, holograms, watermarks, security inks containing optically variable pigments, magnetic or magnetizable thin film interference pigments, interference coated particles, thermochromic pigments, photochromic pigments, luminescent, infrared absorbing, ultraviolet absorbing or magnetic compounds. In addition to these security features, security documents often bear a tactile or perceptible surface profile pattern that can be created by printing.

Intaglio printing is used in the field of security documents, particularly banknotes, and provides the most consistent and high quality fine line printing. In addition, intaglio printing endows the printed document with well-known and recognizable relief features, in particular an unmistakable touch sensation.

The term intaglio printing in the context of this application will apply to the so-called engraved steel stamp or engraved copper plate embossing process, which is well known to those skilled in the art. The following does not apply to well-known rotogravure or gravure printing processes that use other types of inks, wherein said gravure inks exhibit very low viscosity values compared to intaglio inks.

During intaglio printing processes, one or more inks are supplied to a rotating engraved steel plate cylinder or impression cylinder carrying one or more plate plates with an engraved design or image to be printed, said inks being applied to the engraved surface of the plate cylinder or plate and to engravings. The plates or cylinders used here are usually chrome-plated, engraved nickel plates or cylinders made by galvanically replicating the original copper plate, often hand-engraved. During the printing process, ink not only fills the engravings on the plate cylinder/plates, it is also applied to a flat surface without an image of said plate cylinder/plates. Therefore, it is important to thoroughly remove the ink from the flat surface of the engraved plate cylinder/plates before the substrate printing process is carried out. This is usually achieved by rotating the excess ink cylinder in the opposite direction to the engraved plate cylinder, so that the two contacting surfaces move in opposite directions. Under the right conditions and, most importantly, the right ink, this will remove excess ink from the flat surface so that the ink on the engraved plate cylinder/plates remains only in the engravings. This process of removing excess ink is unique to gravure printing. The excess paint removal cylinder is in turn constantly cleaned.

An inked intaglio plate is brought into contact with a substrate, such as paper, composite, or plastic material in sheet or web form, and the ink is transferred under pressure from the engravings of the intaglio plate to form a thick raised printed design on the substrate. The high pressure deforms the deckle material, forcing the backing into the engravings on the engraved plate cylinder. This causes a small amount of ink to accumulate on the substrate and a relief to appear corresponding to the engravings on the surface of the engraved plate cylinder.

As mentioned above herein, the gravure printing process involves removing any excess ink present on the surface of the gravure plate/cylinder. The process of removing excess ink can be carried out using a disposable fibrous material such as, for example, paper or a fabric wiping system (calico) or a polymer roller wiping system (a cylinder for removing excess ink). Because the use of these fibrous materials results in a huge amount of ink-soaked waste that must be disposed of, which poses a potential environmental hazard, and because of the speed of printing on an industrial press, it is preferable that excess ink be removed using a resin cylinder to remove excess ink and a cleaning/wiping solution to clean the resin cylinder to remove excess paint. Removing excess ink with paper or a napkin on an industrial printing machine is practically not used.

- 1 045420

The cylinder deinking method is primarily used in high volume printing and uses a cylinder coated with a material to which ink easily adheres, such as polyvinyl chloride (PVC), to remove excess ink from an engraved plate cylinder. The paint must then be completely removed from the coated surface of the PVC cylinder to remove excess paint before that portion of the surface is returned to contact with the engraved plate cylinder. This is achieved through a combination of scraping, brushing and washing. Due to environmental concerns and VOC regulations, solvent cleaning of the resin cylinder to remove excess paint is virtually no longer used. It is preferred to remove excess paint using an aqueous solution as an emulsifying medium to remove excess paint, and suitable cleaning solutions are an alkaline aqueous wipe containing caustic soda and a surfactant such as, for example, sulphated/sulfonated castor oil (SCO ).

The intaglio ink then needs to be cured or cured. This is usually done either by heating or, more commonly, by oxidative fixation. Curing or curing of oxidation curing inks is generally a slow process which results in oxidation curing inks being more prone to over embossing than radiation curing inks. Moreover, a significant disadvantage of this method is that it is a relatively slow process, and documents suitably printed and laid out in sheet form generally cannot be processed for further processing until a consolidation time period of one to several days. Curing of printing inks by radiation, in particular radiation in the UV and visible region, is known and widely used in the field of printing. Radiation curing provides rapid, almost instantaneous curing/curing of printed ink film and therefore paves the way for increased production speed. Gravure printing with radiation-curable inks, due to their rapid or near-instantaneous curing, reduces the time between printing and handling of printed substrates and allows for more sheets per stack. The presence of VOCs can be avoided by using radiation-curable gravure inks. Radiation-cured gravure inks are also significantly more durable on the press than oxidation-cured inks.

The use of intaglio inks intended for printing security documents, with a polymer cylinder to remove excess ink, is known to be unique and very specific and must satisfy the following requirements: ink fastness before printing, on ink rollers and until printing; rheological properties at the time of ink transfer to the gravure printing plate cylinder and at the time of printing; the ability of ink to be easily and quantitatively removed from non-image areas of the plate (excess ink removal capability) and the ease of cleaning the resin cylinder to remove excess ink with alkaline aqueous wiping solutions (washability).

EP 1751240 A1 discloses energy-curable, in particular UV-visible intaglio printing inks containing acylphosphine oxide as a photoinitiator. The disclosed intaglio inks contain a binder containing one or more oligomers, such as epoxy acrylates, acrylic resin modified oils, urethane acrylates, polyester acrylates, silicone acrylates, acrylic resin modified amines, acrylic saturated resins and acrylic acrylates and/or reactive (meth) acrylate monomers such as polyester(meth)acrylates, polyol(meth)acrylates and polyether(meth)acrylates. A typical intaglio printing ink disclosed in Table. 1 of document EP 1751240 A1, contains an epoxy diacrylate oligomer based on bisphenol-A and tripropylene glycol diacrylate. A typical intaglio ink disclosed in Table 3 of EP 1751240 A1 contains a polyester acrylate fatty acid oligomer and an ethoxylated pentaerythritol tetraacrylate. Opened gravure inks may have poor or no washability.

US 2007/0179211 discloses energy-curable, particularly UV-visible gravure inks containing a pigment, the same binder as described in US 2007/0179211, a photoinitiator and a plasticizer, It is believed that said plasticizer improves the ability to remove excess of said paints. The gravure inks disclosed in the tables of US 2007/0179211 are similar to those disclosed in EP 1751240 A1, but contain dibutyl sebacate, acetyl triethyl citrate, tall oil fatty acid, linseed oil, lauric acid, butyl stearate, oleic acid and hexyl tallate as agents. to remove excess paint (plasticizers). The revealed inks are reported to exhibit improved over-ink removal ability as judged by the cleanliness of the non-printed area and the reduced amount of ink that is transferred to the paper.

EP 2489709 A1 discloses hybrid intaglio inks, i.e. inks that

- 2 045420 giving both the ability to cure under the influence of UV radiation and the ability to oxidative polymerization. The disclosed hybrid intaglio inks contain at least a UV-curable composition, an oxidatively polymerizable composition, a photopolymerization initiator, an oxidative polymerization catalyst, and a pigment, wherein the UV-curable composition comprises an acid-modified epoxy acrylate. The disclosed hybrid gravure inks are reported to exhibit improved over-embossing properties, improved anti-flaking properties, and improved print quality. However, hybrid gravure inks may suffer from reduced shelf life or shelf life with crusting on the surface of the inks and may suffer from poor durability on the gravure printing press.

Thus, there remains a need for radiation-curable gravure inks that provide storage and use durability, optimized rheology, good wipeability, and good washability in standard alkaline aqueous wiping solutions.

Brief description of the invention

Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art discussed above. In a first aspect, the present invention provides a radiation-curable gravure ink comprising:

a) from about 10 to about 60% by weight of one or more radiation-curable compounds, wherein at least one of the one or more radiation-curable compounds is a fatty acid polyester (meth)acrylate oligomer, preferably polyester acrylate fatty acid oligomer;

b) from about 2 to about 20 wt.% one or more photoinitiators, preferably selected from the group consisting of Norrish type I photoinitiators, Norrish type II photoinitiators, and mixtures thereof;

c) from about 5 to about 12 wt.% high molecular weight acid-modified alkyd surfactant and/or alkylarene sulfonic acid surfactant;

d) from about 10 to about 55% by weight of one or more fillers or diluents, preferably selected from the group consisting of carbon fibers, talcs, micas, wollastonites, calcined clays, white clays, kaolins, carbonates, silicas and silicates, sulfates , titanates, titanium dioxides, alumina hydrates, silicon dioxides, colloidal silicon dioxides, montmorillonites, graphites, anatase, rutiles, bentonites, vermiculites, zinc white, zinc sulfides, wood flour, quartz flour, maize starches, natural fibers, synthetic fibers and combinations thereof, and wherein the weight percentage is calculated based on the total weight of the radiation-curable intaglio ink, wherein the viscosity of the radiation-curable intaglio ink is from about 10 to about 50 Pa-s at 40° C. and 200 s ^-1 .

Also described and claimed herein are designs or images formed from the radiation-curable intaglio ink described herein, which designs or images serve as security features on a substrate to which they are applied.

Also described and claimed herein are security documents containing a design or image described in this document.

Also described and claimed herein are methods for producing the drawings or images described herein, said methods including:

a) applying the radiation-curable intaglio ink described herein to the engraved intaglio plate,

b) removing any excess radiation-curable gravure ink using a polymer cylinder to remove excess ink and cleaning said polymer cylinder to remove excess ink with an alkaline aqueous wiping solution in combination with one or more mechanical means,

c) printing a design or image using an engraved gravure plate by applying radiation-curable gravure ink to a substrate; and

d) curing the radiation-curable gravure ink under radiation.

Brief description of drawings

In fig. 1A-B show schematic views of gravure printing machines, wherein the printing machine of FIG. 1A works with direct inking process, and the printing machine

- 3 045420 according to Fig. 1B works with the indirect inking process (Orlov printing process).

Detailed description

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

As used herein, the singular form of object refers to one or more objects and is not necessarily limited to the singular.

As used herein, the term approximately 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 within the range of ±5% of the specified value provide equivalent results or effects in accordance with the present invention.

As used herein, the term and/or or or/and means that either all or only one of the elements of the specified group may be present. For example, A and/or B would mean only A or only B, or both A and B.

As used herein, the term is intended to at least mean one or more, such as one, or two, or three.

The term security document refers to a document that is typically protected from forgery or falsification by at least one security feature. Examples of protected documents include, but are not limited to, valuable documents and valuable commercial items.

The term (meth)acrylate refers to acrylate as well as the corresponding methacrylate.

As used herein, the expression removing excess ink refers to removing intaglio ink from the non-printing areas of the engraved plate cylinder/plates of the intaglio printing machine.

As used herein, the expression washability refers to the ability of an intaglio ink to be emulsified by an alkaline aqueous wiping solution and removed from the polymer barrel to remove excess ink after emulsification by said alkaline aqueous wiping solution using one or more mechanical means.

The viscosity of the radiation-curable gravure inks described herein is from about 10 to 50 Pa-s, preferably from about 10 to about 40 Pa-s, at 40°C and at a shear rate of 200 s ^-1 , at In this case, the indicated viscosity values were obtained using a Haake Roto Visco 1 rotational rheometer (C20/0.5°; at 40°C and 200 s ^-1 ).

Radiation-curable inks consist of inks that can be cured by exposure to UV-visible wavelengths of radiation (hereinafter referred to herein as UV-visible curable) or by exposure to electron beam radiation (hereinafter referred to as like EL). Radiation-curable paints are known in the art and can be found in standard textbooks such as the Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints series published in 7 volumes in 1997-1998. edited by John Wiley & Sons in association with SITA Technology Limited. Radiation-assisted curing, in particular UV-visible curing, advantageously leads to very fast curing processes and therefore significantly reduces ink curing times, thereby enabling high production speeds while preventing over-embossing and blocking problems. The radiation-curable gravure inks described herein are preferably UV-visible gravure inks.

The radiation-curable gravure ink described herein contains from about 10 to about 60 weight percent, preferably from about 15 to about 50 weight percent, of one or more radiation-curable compounds, wherein at least one of the one or more radiation-curable compounds is a polyester (meth)acrylate fatty acid oligomer described herein, preferably a polyester acrylate fatty acid oligomer, more preferably a polyester monoacrylate fatty acid oligomer, a polyester diacrylate fatty acid oligomer, a polyester triacrylate fatty acid oligomer, a polyester tetraacrylate fatty acid oligomer, a polyester hexaacrylate fatty acid oligomer, or a mixture thereof, even more preferably a polyester tetraacrylate fatty acid oligomer and/or a polyester hexaacrylate fatty acid oligomer, the weight percentage being calculated based on the total weight cured by radiation of intaglio printing ink.

In one embodiment, at least one of the one or more radiation-curable compounds is a polyester (meth)acrylate fatty acid oligomer described herein, preferably a polyester tetra-acrylate fatty acid oligomer described herein, or a polyester hexaacrylate fatty acid oligomer described herein.

In another embodiment, at least one of the one or more radiation-curable compounds is a polyester (meth)acrylate fatty acid oligomer described herein, preferably a polyester tetraacrylate fatty acid oligomer described herein or a polyester hexaacrylate oligomer fatty acid described herein, and at least the other is an active diluent in the form of a (meth)acrylate monomer selected from the group consisting of mono(meth)acrylate monomers, di(meth)acrylate monomers, tri(meth)acrylate monomers, tetra(meth)acrylate monomers, penta(meth)acrylate monomers, hexa(meth)acrylate monomers, and mixtures thereof, wherein the total amount of the polyester(meth)acrylate fatty acid oligomer described herein and the active diluent of The (meth)acrylate monomer is from about 10 to about 60 weight percent, preferably from about 15 to about 50 weight percent, the weight percentage being calculated based on the total weight of the radiation-curable gravure ink. The term at least another being a (meth)acrylate monomer active diluent also includes any combination of two or more (meth)acrylate monomer active diluents independently selected from the group consisting of mono(meth)acrylate monomers, di (meth)acrylate monomers, tri(meth)acrylate monomers, tetra(meth)acrylate monomers, penta(meth)acrylate monomers and hexa(meth)acrylate monomers, as described herein.

In another embodiment, at least one of the one or more radiation-curable compounds is a polyester (meth)acrylate fatty acid oligomer described herein, preferably a polyester tetraacrylate fatty acid oligomer described herein or a polyester hexaacrylate oligomer fatty acid described herein, and at least the other is a urethane (meth)acrylate oligomer and/or epoxy (meth)acrylate oligomer, wherein the total amount of a polyester (meth)acrylate fatty acid oligomer described herein is and the urethane(meth)acrylate oligomer and/or epoxy(meth)acrylate oligomer is from about 10 to about 60 weight percent, preferably from about 15 to about 50 weight percent, the weight percentage being calculated based on the total weight cured under exposure to radiation from intaglio printing ink.

In another embodiment, at least one of the one or more radiation-curable compounds is a polyester (meth)acrylate fatty acid oligomer described herein, preferably a polyester tetraacrylate fatty acid oligomer described herein or a polyester hexaacrylate oligomer fatty acid described herein, at least the other is an active diluent in the form of a (meth)acrylate monomer selected from the group consisting of mono(meth)acrylate monomers, di(meth)acrylate monomers, tri(meth)acrylate monomers , tetra(meth)acrylate monomers, penta(meth)acrylate monomers, hexa(meth)acrylate monomers, and mixtures thereof, and at least the other is a urethane(meth)acrylate oligomer and/or an epoxy(meth)acrylate oligomer, wherein a total amount of at least one of one or more radiation-curable compounds of a polyester (meth)acrylate fatty acid oligomer described herein, an active (meth)acrylate monomer, and a urethane (meth)acrylate oligomer and/or epoxy The (meth)acrylate oligomer is from about 10 to about 60 weight percent, preferably from about 15 to about 50 weight percent, the weight percentage being calculated based on the total weight of the radiation-curable gravure ink. The expression at least another being a (meth)acrylate monomer active diluent also means any combination of two or more (meth)acrylate monomer active diluents independently selected from the group consisting of mono(meth)acrylate monomers, di (meth)acrylate monomers, tri(meth)acrylate monomers, tetra(meth)acrylate monomers, penta(meth)acrylate monomers, hexa(meth)acrylate monomers, as described herein.

The polyester (meth)acrylate fatty acid oligomer described herein, preferably the polyester tetraacrylate fatty acid oligomer described herein or the polyester hexaacrylate fatty acid oligomer described herein, contains fatty acid residues. Preferably, the fatty acid residues of a polyester(meth)acrylate fatty acid oligomer described herein, particularly a polyestertetraacrylate fatty acid oligomer described herein or a polyesterhexacrylate fatty acid oligomer described herein, are a saturated fatty acid residue , more preferably the remainder of the saturated fat

- 5 045420 acids with 14-20 carbon atoms (ie myristic acid, palmitic acid, stearic acid and arachidic acid), even more preferably with 16-18 carbon atoms (ie palmitic acid and stearic acid). In a preferred embodiment, the radiation-curable intaglio ink described herein comprises at least one of one or more radiation-curable polyethertetraacrylate fatty acid oligomer compounds described herein and/or polyetherhexacrylate fatty acid oligomer, wherein the fatty acid moieties are saturated fatty acids, more preferably saturated fatty acid moieties with 14-20 carbon atoms (i.e. myristic acid, palmitic acid, stearic acid and arachidic acid), even more preferably with 16-18 carbon atoms (i.e. palmitic acid and stearic acid). Particularly suitable polyethertetraacrylate fatty acid oligomers and polyesterhexacrylate fatty acid oligomers are marketed by Allnex under the designations EBECRYL® 657, EBECRYL® 1657, EBECRYL® 870, EBECRYL® 1870 and EBECRYL® 450.

In one embodiment, the radiation-curable gravure ink described herein comprises one or more radiation-curable compounds, wherein one or more other compounds of the one or more radiation-curable compounds described herein are are active diluents in the form of (meth)acrylate monomer. Active thinners are used to reduce the viscosity of paint. One or more active diluents are selected from the group consisting of mono(meth)acrylates, di(meth)acrylates, tri(meth)acrylates, tetra(meth)acrylates, penta(meth)acrylates, hexa(meth)acrylates and mixtures thereof, more preferably selected from the group consisting of tri(meth)acrylates, tetra(meth)acrylates and mixtures thereof. In one embodiment, the one or more active diluents are selected from the group consisting of monoacrylates, diacrylates, triacrylates, tetraacrylates, pentaacrylates, hexaacrylates, and mixtures thereof, more preferably selected from the group consisting of triacrylates, tetraacrylates, and mixtures thereof.

Examples of di(meth)acrylate compounds include, but are not limited to, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, alkoxylated diacrylate, alkoxylated dimethacrylate, esterdiol diacrylate, ethoxylated bisphenol-A diacrylate, ethoxylated bisphenol-A dimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, polyethylene glycol diacrylate (e.g. PEG 200, 300 , 400, 600 and diacrylates), polyethylene glycol dimethacrylate (e.g. PEG 200, 400, 600 and 800 dimethacrylate), 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, alkoxylated neopentyl glycol diacrylate (e.g. propoxylated neopentyl glycol diacrylate), neopentyl gly cold methacrylate, tricyclodecanedimethanol diacrylate, tricyclodecanedimethanol dimethacrylate, alkoxylated diacrylate based bisphenol-A (eg, ethoxylated bisphenol-A diacrylate and propoxylated bisphenol-A diacrylate), alkoxylated bisphenol-A dimethacrylate (eg, ethoxylated bisphenol-A dimethacrylate), and mixtures thereof.

Examples of tri(meth)acrylates include, but are not limited to, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, alkoxylated trimethylolpropane triacrylate (for example, ethoxylated trimethylolpropane triacrylate and propoxylated trimethylolpropane triacrylate), alkoxylated trimethylolpropane trimethacrylate (for example, ethoxylated trimethylolpropane trimethacrylate and propoxylated trimethylolpropane trimethacrylate). acrylate), alkoxylated glycerol triacrylate (e.g. ethoxylated glycerol triacrylate and propoxylated glycerol triacrylate), pentaerythritol triacrylate , alkoxylated pentaerythritol triacrylate (eg, ethoxylated pentaerythritol triacrylate, propoxylated pentaerythritol triacrylate), and mixtures thereof.

Examples of tetra(meth)acrylates include, but are not limited to, ditrimethylolpropanetetraacrylate, pentaerythritol tetraacrylate, alkoxylated pentaerythritol tetraacrylate (eg, ethoxylated pentaerythritol tetraacrylate and propoxylated pentaerythritol tetraacrylate), and mixtures thereof.

Examples of penta(meth)acrylates include, but are not limited to, dipentaerythritol pentaacrylate.

Examples of hex(meth)acrylates include, but are not limited to, dipentaerythritol hexaacrylate and ethoxylated sorbitol hexaacrylate.

In one embodiment, the radiation-curable gravure ink described herein comprises one or more radiation-curable compounds, wherein one or more other compounds of the one or more radiation-curable compounds described herein are are urethane (meth)acrylate oligomers and/or epoxy (meth)acrylate oligomers. Suitable examples ure

- 6 045420 tan(meth)acrylate oligomers include, without limitation, aliphatic urethane(meth)acrylate oligomers, in particular diacrylates, triacrylates, tetraacrylates and hexaacrylates, and aromatic (meth)acrylate oligomers, in particular diacrylates, triacrylates, tetraacrylates and hexaacrylates. Urethane(meth)acrylate oligomers can be based on polyethers or polyesters that react with aromatic, aliphatic or cycloaliphatic diisocyanates and capped with hydroxyacrylates. Particularly suitable aliphatic urethane (meth)acrylate oligomers are sold by Rahn under the designation Genomer 4316.

Suitable examples of epoxy(meth)acrylate oligomers include, but are not limited to, aliphatic epoxy(meth)acrylate oligomers, particularly monoacrylates, diacrylates and triacrylates, and aromatic epoxy(meth)acrylate oligomers, particularly bisphenol-A based epoxy(meth)acrylate oligomers, such as the product sold by Allnex under the designation EBECRYL® 1606 EBECRYL® 3608.

As mentioned above, radiation curing of compounds requires the presence of one or more photoinitiators. As mentioned herein and as is known to those skilled in the art, the radiation-curable, particularly the UV-visible intaglio printing ink described herein is capable of curing and curing onto a substrate such as described herein, contains one or more photoinitiators, wherein said one or more photoinitiators are selected according to its/their absorption spectrum/spectra in correlation with the emission spectrum of the radiation source. Depending on the degree of transmission of electromagnetic radiation through the substrate, curing of the gravure ink can be achieved by increasing the irradiation time. However, depending on the substrate material, the irradiation time is limited by the substrate material and its sensitivity to the heat that may be generated by the radiation source.

The one or more photoinitiators described herein are preferably selected from the group consisting of Norrish Type I photoinitiators, Norrish Type II photoinitiators, and mixtures thereof. Norrish type I photoinitiators are preferably selected from the group consisting of amino ketones (eg, alpha-aminoketones), hydroxy ketones (eg, alpha-hydroxy ketones), alkoxy ketones (eg, alpha-alkoxy ketones), acetophenones, ketosulfones, benzyl ketals, benzoin ethers, esters benzoyl formate, phosphine oxides, phenylglyoxylates and mixtures thereof, and are preferably selected from the group consisting of phosphine oxides, alpha-hydroxyketones and mixtures thereof. Norrish type II photoinitiators are preferably selected from the group consisting of combinations of amines, alcohols, ethers, esters or thiols with aromatic ketones, preferably combinations of amines and aromatic ketones, preferably tertiary amines and aromatic ketones. The one or more photoinitiators described herein may be low molecular weight photoinitiators, high molecular weight photoinitiators, and/or polymeric photoinitiators. One or more photoinitiators described herein may be multifunctional photoinitiators. One or more of the photoinitiators described herein may be copolymerizable photoinitiators, i.e. photoinitiators bearing one or more groups (eg, acrylate groups) capable of co-reacting during the radiation curing reaction.

It may also be advantageous to include the sensitizer together with one or more photoinitiators to achieve effective curing. Typical examples of suitable photosensitizers include, but are not limited to, 2-methylthioxanthone; 2,4-dimethylthioxanthone; 2,4diethylthioxanthone; 2-isopropylthioxanthone (ITX); 1-chloro-2-propoxythioxanthone (CPTX); 1-chloro-4propoxythioxanthone, 2-chlorothioxanthone (CTX) and 2,4-diethylthioxanthone (DETX); and polymeric thioxanthone derivatives and mixtures of two or more of them.

Suitable examples of alpha-hydroxyketones include, but are not limited to (1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one); 1-hydroxycyclohexylphenylketone; 2-hydroxy-2-methyl-1 phenylpropan-1-one; 2-hydroxy-2-methyl-1-(4-tert-butyl)phenylpropan-1-one; 2-hydroxy-1-[4-[[4-(2-hydroxy-2-methylpropanoyl)phenyl]methyl]phenyl]-2-methylpropan-1-one; 2-hydroxy-1-[4-[4-(2-hydroxy-2-methylpropanoyl)phenoxy]phenyl]-2-methylpropan-1-one; and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone].

Suitable examples of alpha-aminoketones include those containing a benzoyl moiety, in other words so-called alpha-aminoacetophenones, for example 2-methyl-1-[4-(methylthio)phenyl]2-morpholinopropan-1-one; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one; and 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)butan-1-one.

Suitable examples of acetophenones include, but are not limited to, 2,2-diethoxyacetophenone; 2-ethylhexyl-4-dimethylaminobenzoate and 2-methoxy-2-phenylacetophenone.

A suitable example of a ketosulfone includes, but is not limited to, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one.

Suitable examples of benzyl ketals include, but are not limited to, 2,2-dimethoxy-2-phenylacetophenone.

- 7 045420

Suitable examples of benzoin ethers include, but are not limited to, benzoin methyl ether; benzoinisopropyl ether; 2-ethoxy-1,2-diphenylethanone; 2-isopropoxy-1,2diphenylethanone; 2-isobutoxy-1,2-diphenylethanone; 2-butoxy-1,2-diphenylethanone; 2,2-dimethoxy-1,2diphenylethanone; and 2,2-diethoxyacetophenone.

Suitable examples of phosphine oxides include, but are not limited to, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate; phenylbis(2,4,6trimethylbenzoyl)phosphine oxide; bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; substituted acyl phosphine oxides sold as Speedcure XKm from Lambson; a mixture of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphineoxide; a mixture of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methylpropiophenone, a mixture of phenylbis(2,4,6trimethylbenzoyl)phosphineoxide and 2-hydroxy-2-methylpropiophenone and a mixture of ethyl(2,4,6trimethylbenzoyl)phenylphosphinate and 2-hydroxy-2-methylpropiophenone.

Suitable examples of phenylglyoxylates include, but are not limited to, methyl benzoyl formate; 2-[2oxo-2-phenylacetoxyethoxy]ethyl 2-oxo-2-phenylacetate; and a mixture of 2-[2-oxo-2-phenylacetoxyethoxy]ethyl 2-oxo-2-phenylacetate and hydroxyphenylacetic acid 2-[2-hydroxyethoxy]ethyl ester.

Suitable examples of aromatic ketones include, but are not limited to, benzophenone; 2methylbenzophenone; 3-methylbenzophenone; 4-methylbenzophenone; 2,4,6-trimethylbenzophenone; a mixture of 4methylbenzophenone and 2,4,6-trimethylbenzophenone; 3,3'-dimethyl-4-methoxybenzophenone;2-hydroxybenzophenone;3-hydroxybenzophenone;4-hydroxybenzophenone;4-chlorobenzophenone;4,4'-dichlorobenzophenonemethyl orthobenzoyl benzoate; 4-phenylbenzophenone; 4-(4-methylphenylthio)benzophenone; 4,4'bis(dimethylamino)benzophenone (Michler's ketone); 4,4'-bis(diethylamino)benzophenone;4,4'-bis(ethylmethylamino)benzophenone;4,4'-diphenoxybenzophenone;4,4'-bis(4-isopropylphenoxy)benzophenone;2methylthioxanthone;2,4-dimethylthioxanthone;2,4-diethylthioxanthone; 2-isopropylthioxanthone (ITX); 1-chloro2-propoxythioxanthone (CPTX); 1-chloro-4-propoxythioxanthone; 2-chlorothioxanthone (CTX) and 2,4diethylthioxanthone (DETX); polymeric thioxanthones; xanthone; 2-benzoylxanthone; anthraquinone; 2ethylanthraquinone; 9,10-phenanthrenequinone; methyl benzoyl formate; ethyl benzoyl formate; camphorquinone; Dibenzosuberenone.

Suitable examples of amines include, but are not limited to, methyldiethanolamine; triethanolamine; ethyl 4-dimethylaminobenzoate; tertiary amines, modified acrylic resin (eg 2(dimethylamino)ethyl methacrylate); 2-dimethylaminoethyl methacrylate; monoalkyl, dialkyl or trialkyl tertiary amine derivatives; and polymeric monoalkyl, dialkyl or trialkyl tertiary amine derivatives.

Other examples of photoinitiators used can be found in standard 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 1998 by John Wiley & Sons in association with SITA Technology Limited.

One or more photoinitiators described herein are preferably present in the radiation-curable gravure ink described herein in an amount of from about 2 to about 20 wt.%, more preferably in an amount from about 5 to about 15 wt. .%, with the weight percentage calculated based on the total weight of the radiation-curable gravure ink.

The radiation-curable intaglio ink described herein contains from about 5 to about 12 wt.%, preferably from about 5.5 to about 10 wt.%, or a high molecular weight acid-modified alkyd surfactant described in herein, and/or an alkylarene sulfonic acid surfactant described herein, wherein the weight percentage is calculated based on the total weight of the radiation-curable gravure ink.

In one embodiment, the radiation-curable intaglio ink described herein contains from about 5 to about 12 wt.%, preferably from about 5.5 to about 10 wt.%, high molecular weight acid-modified alkyd surfactant, preferably having a molecular weight of from about 3000, the weight percentage being calculated based on the total weight of the radiation-curable intaglio ink. The molecular weight of the high molecular weight acid-modified alkyd surfactant is preferably from about 3000, as described herein, to about 20,000, preferably from about 5,000 to about 15,000. The molecular weight of the high molecular weight acid-modified alkyd surfactant is measured using GPC (gel -permeation chromatography) using Agilent GPC50+, wherein the specified device is equipped with an isocratic pump, a degasser, an autosampler and a triple detector containing a differential refractometer, a viscometer and a two-angle light scattering detector (15° and 90°). A calibration curve (^(molecular weight) = ^retention volume)) is prepared using twelve polymethyl methacrylate (PMMA) standards (with molecular weights ranging from 650 to 2,299,000 g/mol). Connect in series one guard column (column length 50 mm, internal diameter 7.5 mm) and three Polargel columns M, M and L (column length 300 mm, internal diameter 7.5 mm; stationary phase: hydrophobic and hydrophilic copolymers with particle size 8 µm). During measurement, the temperature is fixed at 40°C. Samples analyzed contained 3 mg/mL of high molecular weight acid-modified alkyd surfactant dissolved in THF (ACROS ORGANICS, 99.9%, anhydrous) and 100 μL injected at a rate of 1 mL/min. GPC provided the relative molecular weight of the polymer as the weight average molecular weight equivalent to PMMA (PMMA eq. molecular weight).

The high molecular weight acid-modified alkyd surfactant described herein contains unsaturated fatty acid residues, saturated fatty acid residues, or mixtures thereof, and also contains acidic groups. Acid-modified alkyd surfactants are the reaction products of one or more polyhydric alcohols (polyols) (such as glycerol, polyglycerol 3-10, trimethylolpropane, monopentaerythritol, dipentaerythritol, sorbitol, alkoxylated sorbitol, etc.), one or more polycarboxylic compounds (such as phthalic acid, isophthalic acid, terephthalic acid, maleic acid, aliphatic diacid, derivatives thereof or anhydride thereof) and one or more fatty acid compounds. Saturated and unsaturated fatty acid compounds 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, lard, liver fats, tuna oil, sperm whale oil and/or tall oil and waxes. Vegetable sources may include waxes and/or oils, such as vegetable oils and/or non-vegetable oils. Examples of vegetable oils include, but are not limited to, bitter gourd oil, borage oil, calendula oil, canola oil, castor oil oil, Chinese tree oil, coconut oil, pine seed oil, corn seed oil, cotton seed oil, dehydrated castor oil, flaxseed oil, grape seed oil , Jacaranda mimosifolia seed, drying oil, palm oil, palm kernel oil, ground nut oil, pomegranate seed oil, rapeseed oil, safflower oil, trichosanth serpentine oil, soybean (bean) oil, sunflower oil, tung oil and/or oil from wheat sprouts. Artificial sources include synthetic waxes (such as microcrystalline and/or paraffin wax), distillate petroleum tailings and/or products produced by chemical or biochemical synthetic processes. 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-9,11,13triene[a-eleostearic] acid (C ₁₈ H ₃₀ O ₂ ), lycanic acid, (9Z,12Z)octadeca-9,12-diene[linoic] acid (C ₁₈ H ₃₂ O ₂ ), (5Z,8Z,11Z,14Z)-eicose-5,8,11,14-tetraenoic[arachidonic] acid (C ₂₀ H ₃₂ O ₂ ), 12-hydroxy-(9Z)octadeca-9 -enoic [ricinoleic] acid (C ₁₈ H ₃₄ O ₃ ), (Z)-docosan-13enoic [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)-docose-7,10,13,16,19-pentaenoic [clunanodonic] acid and mixtures thereof. Suitable fatty acids include 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, nisic and eleostearic acids or mixtures thereof , typically used as mixtures of fatty acids derived from natural or synthetic oils.

In one embodiment, the high molecular weight acid-modified alkyd surfactant described herein preferably has an acid sign that is equal to or greater than about 30, preferably greater than about 50, and more preferably greater than about 60, which acid sign is measured by titration. Specifically, a solution of high molecular weight acid-modified alkyd surfactant (1 g) in 50 ml of a 1:1 xylene/ethanol mixture is titrated with 0.5 M KOH aqueous solution and phenolphthalein as a pH indicator, using, for example, Dosimat 776 (from the company Metrohm).

In another embodiment, the radiation-curable intaglio ink described herein contains from about 5 to about 12 wt.%, preferably from about 5.5 to about 10 wt.% of the alkylarene sulfonic acid surfactant described herein. document, the weight percentage being calculated based on the total weight of the radiation-curable intaglio ink. The alkylarene sulfonic acid surfactant described herein is preferably a (C ₁ -C ₁₆ -alkyl)arene sulfonic acid such as mono-, di- and tri-(C ₁ -C ₁₆ -alkyl)benzenesulfonic acids and mono-, di- - and tri-(C ₁ -C ₁₆ -alkyl)naphthalene sulfonic acids.

- 9 045420

Examples of alkylarene sulfonic acid surfactants include dibutyl naphthalene sulfonate, dodecyl diphenyl ether sulfonate, cumyl sulfonate, octyl benzene sulfonate, nonyl benzene sulfonate, dodecyl benzene sulfonate and tridecyl benzene sulfonate. Preferably, the alkylarene sulfonic acid surfactant described herein is a mono- or di(C ₄ -C ₁₄ -alkyl)naphthalene sulfonic acid or mono- or di-(C ₄ -C ₁₄ -alkyl)benzenesulfonic acid, in particular mono-( C ₄ -C ₁₄ -alkyl)benzenesulfonic acid. More preferably, the alkylarene sulfonic acid surfactant described herein is an alkali metal salt (eg, sodium or potassium salt), an alkaline earth metal salt (eg, calcium salt), an ammonium salt, or an alkyl-substituted ammonium salt (C ₄ - C ₁₄ -alkyl)arenesulfonic acids. Even more preferably, the alkylarene sulfonic acid surfactant described herein is an alkali metal salt (eg, sodium or potassium salt), an alkaline earth metal salt (eg, calcium salt), an ammonium salt, or an alkyl-substituted ammonium salt of mono-(C ₄ -C ₁₄ -alkyl)benzenesulfonic acids. Even more preferably, the alkylarene sulfonic acid surfactant described herein is an ammonium salt or an alkyl-substituted ammonium salt of a mono-(C ₄ -C ₁₄ -alkyl)benzenesulfonic acid, particularly an ammonium salt or an alkyl-substituted ammonium salt of a mono-(C ₁₂ -alkyl)benzenesulfonic acids (i.e., ammonium salt or alkyl-substituted ammonium salt of dodecylbenzenesulfonic acid). A particularly suitable example of an alkylarene sulfonic acid surfactant is marketed by Croda under the class number Zephrym™ 3300B.

The hydrophilic-lipophilic balance (HLB) of the alkylarene sulfonic acid surfactant described herein is preferably greater than 8, more preferably greater than or equal to 10, and even more preferably greater than or equal to 11, said HLB value and its measurement being described in The HLB System , a time saving guide to emulsifier selection, Ed by ICI Americas Inc. 1976.

Preferably, the radiation-curable intaglio ink described herein contains the high molecular weight acid-modified alkyd surfactant described herein because the inks exhibit improved physical and chemical resistance compared to radiation-curable intaglio ink. described herein, containing an alkylarene sulfonic acid surfactant described herein.

The radiation-curable intaglio ink described herein contains from about 10 to about 55 wt.%, preferably from about 20 to about 55 wt.%, more preferably from about 30 to about 55 wt.% of one or more excipients or diluents described herein. One or more fillers or diluents described herein are preferably selected from the group consisting of carbon fibers, talcs, micas (muscovite), wollastonites, calcined clays, white clays, kaolins, carbonates (e.g. calcium carbonate, sodium aluminum carbonate) , silicon dioxides and silicates (for example, magnesium silicate, aluminum silicate), sulfates (for example, magnesium sulfate, barium sulfate), titanates (for example, potassium titanate), titanium dioxides, alumina hydrates, silicon dioxides, colloidal silicon dioxides, montmorillonites, graphites, anatase, rutiles, bentonites, vermiculites, zinc white, zinc sulfides, wood flour, quartz flour, maize starches, natural fibers, synthetic fibers and combinations thereof.

The radiation-curable intaglio ink described herein may further contain one or more waxes described herein. The one or more waxes described herein are preferably selected from the group consisting of synthetic waxes, petroleum waxes and natural waxes. Preferably, one or more waxes is selected from the group consisting of microcrystalline waxes, paraffin waxes, polyethylene waxes, fluorocarbon waxes, polytetrafluoroethylene waxes, Fischer-Tropsch waxes, silicone fluids, beeswaxes, candelilla waxes, montane waxes, carnauba waxes and mixtures thereof, wherein the weight percentage is calculated based on the total weight of the radiation-curable intaglio ink. If present, one or more waxes are preferably present in an amount of from about 1 to about 7% by weight, preferably from about 3 to about 6.5% by weight, the weight percentage being calculated based on the total weight of the radiation-curable paint for intaglio printing.

The radiation-curable gravure ink described herein may further comprise one or more coloring components selected from the group consisting of permanent color pigments, dyes, and mixtures thereof. If present, one or more coloring components are preferably present in the radiation-curable intaglio ink described herein in an amount of from about 1 to about 10% by weight, more preferably in an amount of from about 3 to about 10% by weight, wherein the weight percentage is calculated based on the total weight of the radiation-curable intaglio ink. In one embodiment, the radiation-curable gravure ink described herein may further comprise one or more optically variable pigments, such as those described herein, and one or more coloring components, such as those described in this document.

The permanent color pigment components described herein may be organic or inorganic pigment particles. Typical examples of organic and inorganic permanent color pigments include, but are not limited to, CI Pigment Yellow 12, CI Pigment Yellow 42, CI Pigment Yellow 93, 109, CI Pigment Yellow 110, CI Pigment Yellow 147, CI Pigment Yellow 173, CI Pigment Orange 34, CI Pigment Orange 48, CI Pigment Orange 49, CI Pigment Orange 61, CI Pigment Orange 71 CI Pigment Orange 73, CI Pigment Red 9, CI Pigment Red 22, CI Pigment Red 23, CI Pigment Red 57-1. CI Pigment Red 67, CI Pigment Red 122, CI Pigment Red 144, CI Pigment Red 146, CI Pigment Red 170, CI Pigment Red 177, CI Pigment Red 179, CI Pigment Red 185, CI Pigment Red 202, CI Pigment Red 224, CI Pigment Red 242, CI Pigment Red 254, CI Pigment Red 264, CI Pigment Brown 23, CI Pigment Blue 15, CI Pigment Blue 15:3, CI Pigment Blue 60, CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Violet 32, CI Pigment Violet 37, CI Pigment Green 7, CI Pigment Green 36, CI Pigment Black 7, CI Pigment Black 11, metal oxides, antimony yellow, lead chromate, lead chromate sulfate, lead molybdate, ultramarine blue, cobalt blue, manganese blue, green chromium oxide, green hydrated chromium oxide, green cobalt and metal sulfides such as cerium sulfide or cadmium sulfide, cadmium sulfoselenides, zinc ferrite, bismuth vanadate, Prussian blue, Fe ₃ O ₄ , carbon black, azo pigments, azomethine, methine , anthraquinone, phthalocyanine, perinone, perylene, diketopyrrolopyrrole pigments, thioindigopigments, thiazinindigopigments, dioxazine, iminoisoindoline, iminoisoindolinone, quinacridone, flavantrone, indantrone, anthrapyrimidine and quinophthalone pigments.

Dyes suitable for the radiation-curable gravure ink described herein are known in the art, and said dyes may be reactive dyes, direct dyes, anionic dyes, cationic dyes, acid dyes, basic dyes, food dyes , metal complex dyes, soluble dyes, as well as their mixtures. Typical examples of dyes suitable for the present invention are selected from the group consisting of coumarins, cyanines, oxazines, uranines, phthalocyanines, indolinocyanines, triphenylmethanes, naphthalocyanines, indonanaphthalo-metal dyes, anthraquinones, anthrapyridones, azo dyes, rhodamines, squarylium dyes, croconium dyes and mixtures of them. Typical examples of dyes suitable for the present invention are selected from the group consisting of CI Acid Yellow 1, 3, 5, 7, 11, 17, 19, 23, 25, 29, 36, 38, 40, 42, 44, 49, 54, 59, 61, 70, 72, 73, 75, 76, 78, 79, 98, 99, 110, 111, 121, 127, 131, 135, 142, 157, 162, 164, 165, 194, 204, 236, 245; CI Direct Yellow 1, 8, 11, 12, 24, 26, 27, 33, 39, 44, 50, 58, 85, 86, 87, 88, 89, 98, 106, 107, 110, 132, 142, 144 ; CI Basic Yellow 13, 28, 65; CI Reactive Yellow 1, 2, 3, 4, 6, 7, 11, 12, 13, 14, 15, 16, 17, 18, 22, 23, 24, 25, 26, 27, 37, 42; CI Food Yellow 3, 4; CI Acid Orange 1, 3, 7, 10, 20, 76, 142, 144; CI Basic Orange 1, 2, 59; CI Food Orange 2; CI Orange B; CI Acid Red 1, 4, 6, 8, 9, 13, 14, 18, 26, 27, 32, 35, 37, 42, 51, 52, 57, 73, 75, 77, 80, 82, 85, 87 , 88, 89, 92, 94, 97, 106, 111, 114, 115, 117, 118, 119, 129, 130, 131, 133, 134, 138, 143, 145, 154, 155, 158, 168, 180 , 183, 184, 186, 194, 198, 209, 211, 215, 219, 221, 249, 252, 254, 262, 265, 274, 282, 289, 303, 317, 320, 321, 322, 357, 359 ; CI Basic Red 1, 2, 14, 28; CI Direct Red 1, 2, 4, 9, 11, 13, 17, 20, 23, 24, 28, 31, 33, 37, 39, 44, 46, 62, 63, 75, 79, 80, 81, 83 , 84, 89, 95, 99, 113, 197, 201, 218, 220, 224, 225, 226, 227, 228, 229, 230, 231, 253; CI Reactive Red 1, 2, 3, 4, 5, 6, 7, 8, 11, 12, 13, 15, 16, 17, 19, 20, 21, 22, 23, 24, 28, 29, 31, 32 , 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45, 46, 49, 50, 58, 59, 63, 64, 108, 180; CI Food Red 1, 7, 9, 14; CI Acid Blue 1, 7, 9, 15, 20, 22, 23, 25, 27, 29, 40, 41, 43, 45, 54, 59, 60, 62, 72, 74, 78, 80, 82,

83, 90, 92, 93, 100, 102, 103, 104, 112, 113, 117, 120, 126, 127, 129, 130, 131, 138, 140, 142, 143, 151, 154,

158, 161, 166, 167, 168, 170, 171, 182, 183, 184, 187, 192, 193, 199, 203, 204, 205, 229, 234, 236, 249, 254,

285; CI Basic Blue 1, 3, 5, 7, 8, 9, 11, 55, 81; CI Direct Blue 1, 2, 6, 15, 22, 25, 41, 71, 76, 77, 78, 80, 86, 87,

90, 98, 106, 108, 120, 123, 158, 160, 163, 165, 168, 192, 193, 194, 195, 196, 199, 200, 201, 202, 203, 207, 225, 226, 236 , 237, 246, 248, 249; CI Reactive Blue 1, 2, 3, 4, 5, 7, 8, 9, 13, 14, 15, 17, 18, 19, 20, 21, 25, 26, 27, 28, 29, 31, 32, 33 , 34, 37, 38, 39, 40, 41, 43, 44, 46, 77; CI Food Blue 1, 2; CI Acid Green 1, 3, 5, 16, 26, 104; CI Basic Green 1, 4; CI: Food Green 3; CI Acid Violet 9, 17, 90, 102, 121; CI Basic Violet 2, 3, 10, 11, 21; CI Acid Brown 101, 103, 165, 266, 268, 355, 357, 365, 384; CI Basic Brown 1; CI Acid Black 1, 2, 7, 24, 26, 29, 31, 48, 50, 51, 52, 58, 60, 62, 63, 64, 67, 72, 76, 77, 94, 107, 108, 109 , 110, 112, 115, 118, 119, 121, 122, 131, 132, 139, 140, 155, 156, 157, 158, 159, 191, 194; CI Direct Black 17, 19, 22, 32, 39, 51, 56, 62, 71, 74, 77, 94, 105, 106, 107, 108, 112, 113, 117, 118, 132, 133, 146, 154 , 168; CI Reactive Black 1, 3, 4, 5, 6, 8, 9, 10, 12, 13, 14, 18, 31; CI Food Black 2; CI Solvent Yellow 19, CI Solvent Orange 45, CI Solvent Red 8, CI Solvent Green 7, CI Solvent Blue 7, CI Solvent Black 7; CI Disperse Yellow 3, CI and mixtures thereof, Disperse Red 4, 60, CI Disperse Blue 3, metallic azo dyes disclosed in US 5074914, US 5997622, US 6001161, JP 02-080470, JP 62-190272, JP 63-218766 . When present, one or more of the dyes described herein are preferably present in the radiation-curable intaglio ink described herein in an amount of about

- 11 045420 preferably 1 to about 10% by weight, preferably from about 3 to about 10% by weight, the weight percentage being calculated based on the total weight of the radiation-curable intaglio ink.

The radiation-curable gravure ink described herein may further contain one or more optically variable pigments. When present, one or more optically variable pigments are preferably present in the radiation-curable intaglio ink described herein in an amount of from about 1 to about 30 weight percent, the weight percentage being calculated based on the total weight of the radiation-curable radiation of intaglio printing ink.

Optically variable pigments are known in the field of security printing. Optically variable pigments are used to print optically variable elements (also called goniochromatic elements in the art), i.e. elements whose color depends on the viewing angle or angle of incidence. Optically variable elements are used, for example, to protect banknotes and other security documents from counterfeiting and/or illegal reproduction using commonly available office color scanning, printing and copying equipment. Typically, the optically variable pigments may be selected from the group consisting of thin film interference pigments, interference coating pigments, cholesteric liquid crystal pigments, and mixtures thereof, preferably selected from the group consisting of thin film interference pigments, magnetic thin film interference pigments, interference coating pigments and their mixtures.

Examples of films and pigments made from cholesteric liquid crystal materials and their preparation are disclosed in US 5,211,877; US 5362315; US 6423246; EP 1213338 A1; EP 1046692 A1 and EP 0601483 A1, the respective disclosures of which are incorporated herein by reference. Cholesteric liquid crystal pigments may be magnetic. Suitable magnetic cholesteric liquid crystal pigments exhibiting color changing characteristics include, but are not limited to, magnetic single-layer cholesteric liquid crystal pigment particles and magnetic multi-layer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed, for example, in WO 2006/063926 A1, US 6582781 and US 6531221. WO 2006/063926 A1 discloses monolayers and pigment particles derived from them with increased gloss and color change properties, as well as additional special properties , such as magnetizability. The disclosed monolayers and pigment particles, which are obtained from them by grinding said monolayers, include three-dimensionally cross-linked cholesteric liquid crystal mixture and magnetic nanoparticles. US 6,582,781 and US 6,410,130 disclose cholesteric multilayer pigment particles that contain the sequence A1/B/A ² , where A ¹ and A ² may be identical or different and each contains at least one cholesteric layer and B is an intermediate a layer that absorbs all or some of the light transmitted by layers A ¹ and A ² and imparts magnetic properties to said intermediate layer. US 6,531,221 discloses lamellar cholesteric multilayer pigment particles that contain the sequence A/B and optionally C, where A and C are absorbent layers containing pigment particles imparting magnetic properties and B is a cholesteric layer.

Suitable thin film interference pigments exhibiting optically varying characteristics are known to those skilled in the art and are disclosed in US 4,705,300, US 4,705,356, US 4,721,271, US 5,084,351, US 5,214,530, US 5,281,480, US 5,383,995, US 5,569,535, US 55,716 24 and in documents, related to them. If at least a portion of the optically varying pigments consists of thin film interference pigments, it is preferable that the thin film interference pigments comprise a multilayer Fabry-Perot reflector/dielectric/absorber structure, and more preferably a multilayer Fabry-Perot absorber/dielectric/reflector/dielectric/absorber structure, wherein the absorbing layers are partially transmitting and partially reflecting, the dielectric layers are transmitting, and the reflective layer reflects the incoming light. Preferably, the reflective layer is selected from the group consisting of metals, metal alloys and combinations thereof, preferably selected from the group consisting of reflective metals, reflective metal alloys and combinations thereof, and more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and mixtures thereof, and even more preferably aluminum (Al). Preferably, the dielectric layers are independently selected from the group consisting of magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), and mixtures thereof, and more preferably magnesium fluoride (MgF2). Preferably, the absorbent layers are independently selected from the group consisting of chromium (Cr), nickel (Ni), metal alloys and mixtures thereof, and more preferably chromium (Cr). If at least a portion of the optically varying pigments is composed of thin film interference pigments, it is particularly preferred that the thin film interference pigments comprise an absorber/dielectric/reflector/dielectric/absorber multilayer Fabry-Perot structure consisting of a Cr/MgF ₂ /Al/MgF ₂ multilayer structure /Cr.

- 12 045420

The thin film interference pigments described herein may be magnetic thin film interference pigments exhibiting optically variable characteristics known to those skilled in the art and disclosed in US Pat. No. 4,838,648; WO 2002/073250 A2; EP 0686675 B1; WO 03/00801 A2; US 6838166; WO 2007/131833 A1, WO 2015/086257 A1, and in documents related to them. If at least a portion of the optically varying pigments consists of magnetic thin film interference pigments, it is preferred that the magnetic thin film interference pigments comprise a 5-layer Fabry-Perot absorber/dielectric/reflector/dielectric/absorber structure, wherein the reflector and/or absorber is also a magnetic layer such as those disclosed in US 4,838,648 and/or a 7-layer Fabry-Perot absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber structure such as those disclosed in WO 02/073250; and more preferably a 7-layer Fabry-Perot absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber structure. Preferred five-layer Fabry-Perot structures consist of absorber/dielectric/reflector/dielectric/absorber multilayer structures, wherein the reflector and/or absorber is also a magnetic layer, preferably the reflector and/or absorber is a magnetic layer containing nickel, iron and/or or cobalt, and/or a magnetic alloy containing nickel, iron and/or cobalt, and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co).

Preferred six-layer Fabry-Perot structures consist of absorber/dielectric/reflector/magnetic material/dielectric/absorber multilayer structures. Preferred seven-layer Fabry-Perot structures consist of absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber multilayer structures, such as those described in US 4,838,648. Preferably, the reflective layers described herein are independently made of one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni) and alloys thereof, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and alloys thereof, and even more preferably aluminum (Al). Preferably, the dielectric layers are independently made of one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ), cerium fluoride (CeF ₃ ), lanthanum fluoride (LaF ₃ ), sodium aluminum fluorides (for example, Na ₃ AlF ₆ ), neodymium fluoride (NdF ₃ ), samarium fluoride (SmF ₃ ), barium fluoride (BaF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), as well as metal oxides, such as silicon oxide (SiO), silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), more preferably selected from the group consisting of magnesium fluoride (MgF2) and silicon dioxide (SiO2) , and even more preferably magnesium fluoride (MgF2). Preferably, the absorbent layers are independently made of one or more materials selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V) ), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), oxides of these metals, sulfides of these metals, carbides of these metals, as well as alloys of these metals, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), iron (Fe), oxides of these metals and alloys of these metals, and even more preferably selected from the group consisting of from chromium (Cr), nickel (Ni) and alloys of these metals. Preferably, the magnetic layer contains nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic alloy containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co). If magnetic thin film interference pigment particles containing a seven-layer Fabry-Perot structure are preferred, it is especially preferable that the magnetic thin film interference pigment particles contain a seven-layer Fabry-Perot absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber structure consisting of a multilayer Cr/MgF ₂ /Al/M/Al/MgF ₂ /Cr structures, where M represents a magnetic layer containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic alloy containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co). The magnetic thin film interference pigment particles described herein may be multi-layer pigment particles that are considered safe for human health and the environment and are based on, for example, five-layer Fabry-Perot structures, six-layer Fabry-Perot structures and seven-layer Fabry-Perot structures. Feather, wherein said pigment particles comprise one or more magnetic layers comprising a magnetic alloy having a substantially nickel-free composition comprising from about 40 to about 90 weight percent iron, from about 10 to about 50 weight percent chromium, and from about 0 up to approximately 30 wt.% aluminum. Typical examples of multilayer pigment particles that are considered safe for human health and the environment can be found in EP 2402401A1, which is incorporated herein in its entirety by

- 13 045420 references.

Interference coating pigments include, but are not limited to, structures consisting of a substrate selected from the group consisting of metal cores such as titanium, silver, aluminum, copper, chromium, iron, germanium, molybdenum, tantalum or nickel, coated with one or more layers, made of metal oxides, as well as a structure consisting of a core made of synthetic or natural mica, other layered silicates (for example, talc, kaolin and sericite), glasses (for example, borosilicates), silicon dioxides (SiO ₂ ), aluminum oxides ( Al ₂ O ₃ ), titanium oxides (TiO ₂ ), graphites and mixtures thereof, coated with one or more layers made of metal oxides (for example, titanium oxides, zirconium oxides, tin oxides, chromium oxides, nickel oxides, copper oxides and iron oxides), structures described herein above, disclosed, for example, in Chem. Rev. 99 (1999), G. Pfaff and P. Reynders, pp. 1963-1981 and WO 2008/083894. Typical examples of these interference coating pigments include, but are not limited to, silicon oxide cores coated with one or more layers of titanium oxide, tin oxide and/or iron oxide; natural or synthetic mica cores coated with one or more layers made of titanium oxide, silicon oxide and/or iron oxide, in particular mica cores coated with alternating layers of silicon oxide and titanium oxide; borosilicate cores coated with one or more layers of titanium oxide, silicon oxide and/or tin oxide; and titanium oxide cores coated with one or more layers made of iron oxide, iron oxide/hydroxide, chromium oxide, copper oxide, cerium oxide, alumina, silicon oxide, bismuth vanadate, nickel titanate, cobalt titanate and/or doped with antimony fluorine-doped or indium-doped tin oxide; aluminum oxide cores coated with one or more layers of titanium oxide and/or iron oxide. The interference coating pigments described herein may be magnetic and comprise one or more magnetic materials, wherein said pigments consist of a support selected from the group consisting of a core coated with one or more layers, wherein at least one of the core or one or more layers has magnetic properties. For example, suitable interference coating pigments contain a core made of a magnetic material such as those described herein above, wherein said core is coated with one or more layers made of one or more metal oxides, or they have a structure consisting of a core, made of synthetic or natural mica, layered silicates (for example, talc, kaolin and sericite), glasses (for example, borosilicates), silicon dioxides (SiO ₂ ), aluminum oxides (Al ₂ O ₃ ), titanium oxides (TiO ₂ ), graphites and mixtures of two or more of them. Moreover, one or more additional layers, such as coloring layers, may be present.

For embodiments in which magnetic optically variable pigments are contained in the radiation-curable gravure ink described herein, said pigments can be further oriented after gravure printing and before curing by applying a suitable magnetic field and subsequently immobilized in their respective positions and orientations by curing the applied paint.

The radiation-curable gravure ink described herein may further contain one or more UV stabilizers to stabilize the ink, particularly during storage. Typical examples of suitable UV stabilizers include, but are not limited to, hydroquinone, hydroquinone monomethyl ether, 4-tert-butylcatechol, 4-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol (BHT), pyrogallol, phenothiazine (PTZ), 2 ,4diazabicyclo[2.2.2]octane (DABCO), copper(II) salts (such as, for example, copper(II) phenoxide, copper(II) acetylacetonate, copper(II) gluconate, copper(II) tartrate, copper acetate ( II), copper(II) carbamate, copper(II) thiocarbamate, copper(II) dithiocarbamate or copper(II) dimethyldithiocarbamate), copper(I) salts (such as, for example, copper(I) chloride or copper(I) acetate ), tris[K-(hydroxyl-KO)-K-(nitrosoKO)benzolaminato]aluminum, as well as any mixtures thereof. If present, one or more of the UV stabilizers described herein are preferably present in the radiation-curable gravure ink described herein in an amount of from about 0.1 to about 3 wt.%, more preferably in an amount of from about 0.1 to about 2.5% by weight, the weight percentage being calculated based on the total weight of the radiation-curable gravure ink.

The radiation-curable intaglio ink described herein may further comprise one or more machine-readable materials. If present, one or more machine-readable materials are preferably selected from the group consisting of magnetic materials, luminescent materials, electrically conductive materials, infrared absorbing materials, and mixtures thereof. As used herein, the term machine-readable material refers to material that exhibits at least one distinctive property that can be detected by a device or machine, and that can be contained in a layer in such a way as to provide a method of authenticating said layer or an article containing said layer , using specific equipment to detect and/or authenticate it.

- 14 045420

In one embodiment, the one or more machine-readable materials are magnetic materials, preferably magnetic pigment particles, comprising 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 , Y2O3, 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).

In one embodiment, the one or more machine-readable materials are infrared absorbing materials. IR-absorbing materials include inorganic materials, glasses containing significant amounts of IR-absorbing atoms or ions, or substances exhibiting IR absorption as a concomitant effect, IR-absorbing organic compounds, and IR-absorbing organometallic compounds (cation(s) complexes) with organic ligand(s), where either a single cation and/or a single ligand, or both in combination, have IR absorption properties). Non-limiting examples of IR absorbing compounds for use in the present invention include those disclosed in WO 2007/060133 A2, wherein the IR absorbing compound includes a transition element compound, and the absorption of infrared radiation is a consequence of electronic transitions within the d shell of atoms or ions transition elements such as those described in WO 2007/060133 A2. Examples of IR absorbing compounds disclosed in WO 2007/060133 A2 include copper(II) fluoride (CuF₂), copper hydroxyfluoride (CuFOH), copper hydroxide (Cu(OH)₂), copper hydrogen phosphate (Cu₃(P.O.₄)₂*2H₂O), anhydrous copper phosphate (Cu₃(P.O.₄)₂), basic copper(II) phosphates (e.g. Cu₂P.O.₄(OH), Libethenite, whose formula is sometimes written Cu₃(P.O.₄) 2*Cu(OH)2; Cu₃(P.O.₄)(OH)₃, Cornetite, Cu₅(P.O.₄)₃(OH)₄, Pseudomalachite, CuAl₆(P.O.₄)₄(OH)₈-5H₂O Turquoise, etc.), copper (II) pyrophosphate (Cu₂(P₂O₇)*3H₂O), anhydrous copper(II) pyrophosphate (Cu₂(P₂O₇)), copper(II) metaphosphate (Cu(PO₃)₂, more correctly written as Cu₃(P₃O₉)₂), iron(II) fluoride (FeF₂*4H₂O), anhydrous iron(II) fluoride (FeF₂), iron(II) phosphate (Fe₃(P.O.₄)₂*8H₂O, Vivianite), lithium iron(II) phosphate (LiFePO₄, Triphylite), sodium iron (II) phosphate (NaFePO₄, Maricite), iron (II) silicates (Fe₂SiO₄, Fayalite; FexMg₂xSiO₄, Olivine), iron (II) carbonate (FeCO₃, Ankerite, Siderite); Nickel(II) phosphate (Ni(PO₄)₂*8H₂O), and titanium(III) metaphosphate (Ti(P₃O₉)). Moreover, the crystalline IR absorbing material may also be a mixed ionic compound, i.e., in which two or more cations participate in the crystal structure, such as Ca₂Fe(PO₄)₂*4H₂O Anapaite. Similarly, two or more anions may be involved in the structure, as in the basic copper phosphates mentioned, where OHrepresents a second anion, or even both together, as in magnesium iron phosphate fluoride, MgFe(PO₄)F, Wagnerite.

Non-limiting examples of IR absorbing compounds for use in the present invention also include those disclosed in pending application PCT/EP 2019/054055, wherein the IR absorbing compounds are selected from the group consisting of iron (II) orthophosphates without water of crystallization general formula Fe3(PO4)2 with the crystalline structure of graftonite, 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 water 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 represents 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 their mixtures.

Non-limiting examples of IR absorbing compounds for use in the present invention also include tin-doped oxides (such as, for example, antimony tin oxide, ATO), indium-doped oxides (such as, for example, indium tin oxide, ITO), reduced oxides tungsten, tungsten bronzes and mixtures thereof.

The IR absorbing compounds described herein may be used alone or may be used in combinations thereof.

Radiation-curable gravure ink described in this document

- 15 045420 mente, may additionally contain 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 intaglio printing ink, such as consistency (for example, substances that prevent pigment settling in paint, and plasticizers), lubricating properties (waxes), adhesive properties, surface properties (humectants, oleophobic and hydrophobic agents), drying/curing properties (curing accelerators, sensitizers, crosslinkers), etc. The additives described herein may be present in the radiation-curable gravure inks described herein in amounts and forms known in the art, including in the form of so-called nanomaterials having at least one of the additive sizes is in the range of 1-1000 nm.

The present invention further provides methods for producing the radiation-curable intaglio inks described herein and the radiation-curable intaglio inks produced by such methods. The radiation-curable intaglio inks described herein can be prepared by mixing all the ingredients, for example, using a high-speed mixer, thereby forming pastes. The pastes thus formed are then completely mixed and dispersed using, for example, a three-roll mill to obtain homogeneous intaglio pastes.

The radiation-curable intaglio ink described herein is suitable for intaglio printing on a substrate described herein to produce a patterned or imaged security feature. The present invention provides methods for producing a pattern or image and patterns or images produced by such methods. The radiation-curable, particularly UV-visible-curable, gravure ink described herein can be used on a standard gravure printing press equipped with radiation lamps, particularly UV-visible lamps, including low energy lamps (LE or HUV) and LED lamps. The method described herein includes the step of a) applying a radiation-curable gravure ink described herein to an engraved gravure plate.

As mentioned herein, during gravure printing processes, a rotating gravure plate cylinder carrying a plate plate engraved with a design or image to be printed is inked by one or a plurality of selective ink cylinder(s) (or template cylinder), each selective ink cylinder being coated with at least one corresponding color of paint. After step a) described herein, the method described herein further includes step b) removing any excess radiation-curable gravure ink. Specifically, the gravure printing process involves removing any excess ink present on the surface of the gravure plate. In the method described herein, the process of removing excess paint is carried out using a polymer cylinder for removing excess paint, and then said polymer cylinder for removing excess paint is cleaned with an alkaline aqueous wiping solution in combination with one or more mechanical means, in particular one or more brushes and/or pads (such as Scotch-Brite™ pads) to remove the alkaline wipe emulsified paint from the resin cylinder to remove excess paint. After the step of removing excess ink, the method described herein includes the step of c) printing a design or image using an engraved gravure plate by applying a radiation-curable gravure ink to a substrate. That is, after the excess ink removal step b), the inked gravure plate is brought into contact with the substrate described herein, and the radiation-curable ink is transferred under pressure from the engravings of the gravure plate onto the substrate to be printed. , producing a thick printed pattern or image on the substrate. After step c) described herein, the method described herein further includes step d) curing the radiation-curable, in particular UV-visible radiation-curable, gravure ink by radiation, in particular radiation in the UV and visible region.

In fig. 1A and 1B show schematic views of gravure printing machines, wherein the printing machine of FIG. 1A operates with a direct inking process, and the printing machine of FIG. 1B works with the indirect inking process (Orlov printing process). As shown in FIG. 1A and 1B, the rotating gravure plate cylinder (100) carries gravure plates, that is, plates on which the design or image to be printed is engraved. Inking apparatuses are used to facilitate the distribution and transfer of ink from the ink box to the plate cylinder carrying the gravure plate. The ink box acts as a reservoir for gravure printing ink. Three colorful

- 16 045420 apparatus for three inks for intaglio printing is shown in FIG. 1A and 1B, wherein each gravure ink is supplied from a separate ink box, and wherein each of the three ink units independently consists of a series of rollers containing an ink roller (110, 112, 114) coated with a resin material and a template (111 , 113, 115). Since the template is inked by the corresponding ink device and thus transfers one ink to the corresponding plate cylinder (100) (direct process) or to the collecting cylinder (160) (indirect process), it is also referred to in the literature as a selective ink plate cylinder.

According to one embodiment in which the method described herein uses a direct inking process (FIG. 1A), an ink roller (110, 112, 114) transfers the appropriate gravure ink to the template (111, 113, 115), which consists of a sheet with some relief on which ink is applied and which is placed between an inking roller (110, 112, 114) and an intaglio printing plate on a plate cylinder (100). The ink is forced from the relief of the template onto the engravings of the intaglio plate. While the intaglio ink is transferred from the template (111, 113, 160) into the engravings of the intaglio plate, some excess ink may also be transferred to the unengraved surface of the plate. Accordingly, the method described herein includes the step of removing any excess radiation-curable, particularly UV-visible-curable, gravure ink described herein using a polymer cylinder to remove the excess ink and alkaline aqueous cleaning solution. Excess ink on the surface of the plate cylinder is removed by wiping the gravure plate cylinder carrying the gravure plate (100) with a resin cylinder (120) to remove excess ink and cleaning said resin cylinder (120) to remove excess ink with an aqueous alkaline a cleaning solution in combination with one or more mechanical means, in particular one or more brushes and/or pads (eg, Scotch-Brite™ pads). The method described herein further includes the step of printing a design or image using an engraved gravure plate by applying a radiation-curable, particularly a UV-visible-curable, gravure ink to a substrate. Following the step of removing excess ink, the inked intaglio plate is brought into contact with the substrate described herein and ink is transferred under pressure from the engravings of the intaglio plate onto the substrate to be printed to form a pattern or image on the substrate. From the plate cylinder (100), ink is transferred under high pressure to a substrate (130) to be printed to form an intaglio design or image (180). Typically, pressures ranging from several tens to several hundred kN are applied during the gravure printing process. The backpressure cylinder (170) is located on the opposite side of the substrate. The inking boxes, inking rollers (110, 112 and 114) and plate cylinder (100) are usually equipped with a temperature control system. Typical settings for a gravure press include maintaining the ink box temperature at 20°C while the gravure plate cylinder temperature is maintained at about 60 to about 80°C.

According to one embodiment, in which the method described herein uses an indirect inking process (Orlov printing process) (Fig. 1B), in which an ink roller (110, 112, 114) transfers the appropriate intaglio ink to the template ( 111, 113, 115), which consists of a sheet with some relief, onto which paint is applied, and then onto a collecting cylinder (160), called a blank. The collection cylinder (160) then transfers the ink to the plate cylinder (100) carrying the gravure plate. While the intaglio ink is transferred from the template (111, 113, 115) to the collection cylinder (160) and into the engravings of the intaglio plate, some excess ink may also be transferred to the unengraved surface of the plate. Accordingly, the method described herein includes the step of removing any excess radiation-curable, particularly UV-visible, radiation-curable gravure ink described herein, using a polymer cylinder to remove excess ink and clean up said polymer cylinder (120) for removing excess paint with an alkaline aqueous wiping solution in combination with one or more mechanical means, in particular one or more brushes and/or pads (eg, Scotch-Brite™ pads).

The method described herein further includes the step of printing a design or image using an engraved gravure plate by applying a radiation-curable, particularly a UV-visible-curable, gravure ink to a substrate. Following the step of removing excess ink, the inked intaglio plate is brought into contact with the substrate described herein and ink is transferred under pressure from the engravings of the intaglio plate onto the substrate to be printed to form a pattern or image on the substrate. From the uniform

- 17 045420 cylinder (100) transfers ink under high pressure onto the substrate (130) to be printed to form intaglio features (180) in the form of designs or images. Typically, pressures ranging from several tens to several hundred kN are applied during the gravure printing process. The backpressure cylinder (170) is located on the opposite side of the substrate.

The polymer paint removal cylinder described herein is typically made of polyvinyl chloride (PVC) or rubber, preferably PVC.

Typically, suitable aqueous alkaline solutions contain from about 0.3 to about 1.2 wt.%, preferably about 0.8 wt.% alkaline base, such as caustic soda, and from about 0.3 to about 1 0 wt.%, preferably about 0.5 wt.%, surfactant, such as, for example, sulfated/sulphonated castor oil (SCO), the percentage calculated based on the total amount of aqueous alkaline solutions.

The method described herein further includes the step of d) curing the radiation-curable, in particular UV-visible radiation-curable, intaglio printing ink by radiation, in particular UV-visible radiation. As shown in FIG. 1A and 1B, a gravure printing machine, either used in the method described herein with a direct ink process, or used in the method described herein with an indirect ink process, contains a radiation source (150), in particular a UV-visible radiation source for curing a radiation-curable, in particular a UV-visible-curable intaglio ink.

The present invention further provides designs or images that act as security features made from the radiation-curable gravure ink described herein on a substrate described herein.

The substrates described herein may be in sheet or web form and are preferably selected from the group consisting of types of paper or other fibrous materials (including woven and non-woven fibrous materials), such as cellulose, paper-containing materials, glass , 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 variety of fibers, including, without limitation, manila hemp, cotton fiber, flax fiber, wood pulp and mixtures thereof. As is well known to those skilled in the art, cotton fibers and cotton/linen blends are preferred for banknotes, while wood pulp is typically 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 chloride (PVC). High velocity air ejection molded olefin fibers, such as those sold under the trade name Tyvek®, can also be used as the support. Typical examples of metallized plastics or polymers include plastics or polymer materials described above herein, on the surface of which metal is continuously or discontinuously located. Typical examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), alloys thereof, and combinations of two or more of the foregoing metals. Metallization of the plastic or polymeric materials described herein above may be accomplished by an electrodeposition process, a high-vacuum coating process, or a sputtering process. Typical examples of composite materials include, but are not limited to, multilayer structures or laminates of paper and at least one plastic or polymeric material, such as those described herein above, as well as plastic and/or polymeric fibers embedded in 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.

To further enhance security and resistance to counterfeiting and counterfeiting, the substrate described herein may contain printed, coated or laser-marked or laser-perforated characters, watermarks, security threads, fibers, confetti, fluorescent compounds, windows, foils , decals, primers and combinations of two or more of these.

In order to improve durability by increasing the stain resistance or chemical resistance and cleanliness and thus the service life of substrates and protected documents, or to change their aesthetic appearance (for example, optical gloss), one or more protective layers can be additionally applied over an intaglio printed design or image,

- 18 045420 described in this document. If present, one or more protective layers are typically made of protective varnishes, which may be clear, or slightly colored, or tinted, and may be more or less glossy. Protective varnishes can be radiation-curing compositions, heat-curing compositions, or any combination thereof. Preferably, the one or more protective layers are made from radiation-curable compositions, and more preferably UV-visible curable compositions.

As mentioned above herein, the designs or images described herein can be used as security features to protect and authenticate a security document or decorative elements.

Typical examples of decorative items or objects include, but are not limited to, luxury goods, cosmetic packaging, automobile parts, electronic/electrical appliances, furniture, and nail products.

Protected documents include, but are not limited to, valuable documents and valuable commercial items. Typical examples of valuable documents include, but are not limited to, banknotes, legal documents, tickets, cheques, vouchers, stamps and excise stamps, agreements, etc., identification documents such as passports, identity cards, visas, driving licenses, bank cards , credit cards, transaction cards, access documents or cards, entrance tickets, public transport tickets, higher education certificates or academic titles, etc., preferably banknotes, identity documents, title deeds , driver's licenses and credit cards. The term high value commercial item refers to packaging materials, in particular for cosmetic products, nutraceutical products, pharmaceutical products, alcoholic beverages, tobacco products, beverages or food products, electrical/electronic products, textiles or jewelry, i.e. products that must be protected against counterfeiting and/or illegal reproduction to ensure the authenticity of the contents of the packaging, 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 solely by way of example and without limiting the scope of the present invention.

One skilled in the art may make a number of changes within the spirit of the present invention to the specific embodiments described above. Such modifications are covered by the present invention.

In addition, all documents referred to throughout this specification are hereby incorporated into this specification in their entirety as if set forth in their entirety herein.

Examples

The present invention will now be described in more detail with reference to non-limiting examples. The examples below provide more detailed information on the production and use of radiation, in particular UV, curable intaglio inks intended for printing a security feature.

Two series of UV-visible intaglio printing inks according to the present invention were prepared and applied to a substrate (see Table 1A-B):

E1-E4: UV-visible gravure inks containing a) one or more radiation-curable compounds, wherein at least one of the one or more radiation-curable compounds is a polyester acrylate a fatty acid oligomer (E1-E4), optionally at least another of one or more radiation-curable compounds was an active diluent in the form of a (meth)acrylate monomer (E1-E3), and optionally at least another of one or more The radiation-curable compound was an epoxy(meth)acrylate oligomer (E3), b) a photoinitiator, c) a high molecular weight acid-modified alkyd surfactant, d) one or more fillers, e) one or more waxes, f) one or more more pigments and g) one or more UV stabilizers. Comparative inks C1-C4 respectively contained an acrylate oligomer, a urethane oligomer, an epoxy acrylate oligomer, or a chlorinated polyester oligomer, an active diluent in the form of a (meth)acrylate monomer, and a high molecular weight acid-modified alkyd surfactant (i.e., no polyester acrylate oligomer fatty acid), while the comparative paint C5 contains a polyester acrylate fatty acid oligomer and an active diluent in the form of a (meth)acrylate monomer (ie, without high molecular weight acid-modified alkyd surfactant).

E5: UV-visible radiation-curable gravure ink containing: a) one or more radiation-curable compounds, each

- 19 045420 at least one of the one or more radiation-curable compounds is a polyester acrylate fatty acid oligomer, and at least another of the one or more radiation-curable compounds is an active diluent in the form of a (meth)acrylate monomer, b ) a photoinitiator, c) an alkylbenzene sulfonic acid surfactant, d) one or more fillers, e) one or more waxes, f) one or more pigments, and g) one or more UV stabilizers. Comparative inks C6-C9 respectively contained an acrylate oligomer, a urethane oligomer, an epoxy acrylate oligomer or a chlorinated polyester oligomer, an active diluent in the form of a (meth)acrylate monomer and an alkyl benzene sulfonic acid surfactant (i.e. no polyester acrylate fatty acid oligomer) .

Synthesis of High Molecular Weight Acid Modified Alkyd Surfactant

The high molecular weight acid-modified alkyd surfactant contained in C1-C4 and E1-E4 was prepared according to example II, part 1 of EP 0340163 B1, by polycondensation for 5 hours at 220°C of trimethylolpropane (CAS number: 77-99- 6, 99.9% from Penpet) (9 wt%), pentaerythritol (CAS No: 115-77-5, 98% from Perstop) (6 wt%), ethoxylated sorbitol (CAS No: 53694-15 -8, Sorbitol 20x ethoxylated, 99.9% from KLK OLEO) (8 wt.%) as polyols, isophthalic acid (CAS number: 121-91-5, 99.9% from Perstop) (14 wt. %) and 1,2,3,6-tetrahydrophthalic anhydride (CAS No.: 85-43-8, 99.5% from Polynt) (13 wt.%) as polyacids and conjugated fatty acid sunflower oil (CAS No.: 68953-27-5, solids content >99.9% from Smit) (34 wt.%) as fatty acid. The resulting polycondensation product was diluted at room temperature with ethyl diglycol (CAS number: 111-90-0, 99.9% from Brenntag) (16 wt%).

The acid-modified alkyd surfactant thus obtained had an acid value of 60 mg KOH/g (as further described herein) and a weight average molecular weight _Mw of approximately 6600 g/mol (as further described herein).

Method for measuring molecular weight

The weight average molecular weight of the high molecular weight acid modified alkyd surfactant was determined by GPC (gel permeation chromatography) using an Agilent GPC50+, which device is equipped with an isocratic pump, degasser, autosampler and a triple detector containing a differential refractometer, a viscometer and a two-angle light scattering detector ( 15° and 90°). For this particular measurement, only a differential refractometer was used. A calibration curve (log(molecular weight) = retention volume) was generated using twelve polymethyl methacrylate (PMMA) standards (with molecular weights ranging from 650 to 2,299,000 g/mol). One guard column (column length 50 mm, internal diameter 7.5 mm) and three Polargel columns M, M and L (column length 300 mm, internal diameter 7.5 mm; stationary phase: hydrophobic and hydrophilic copolymers with particle size) were connected in series 8 µm). During the measurement, the temperature was fixed at 40°C. The sample analyzed contained 3 mg/mL of high molecular weight acid-modified alkyd surfactant dissolved in THF (ACROS ORGANICS, 99.9%, anhydrous) and 100 μL was injected at a rate of 1 mL/min. GPC provided the relative molecular weight of the surfactant as the weight average molecular weight equivalent to PMMA (PMMA eq. molecular weight).

Acid number method for measuring high molecular weight surfactant

The acid number of the high molecular weight acid-modified alkyd surfactant was determined by titration. A solution of the above surfactant (1 g) in 50 ml of a 1:1 mixture of xylene (99% from Thommen-Furler AO)/ethanol (99% from ACROS ORGANICS) was titrated with 0.5 M aqueous KOH and phenolphthalein as pH indicator using Dosimat 776 (from Metrohm). 0.5 M KOH solution was added until the titrated solution turned from colorless to purple. The acid value given is the average of three measurements.

Preparation of UV-visible gravure inks E1-E5 and C1-C9 (see Table 1A-B)

The ingredients are respectively listed in the table. 1A-B were independently mixed at room temperature using a speed mixer DAC 150 SP CM 31 (Hauschild) for 3 minutes at 2500 rpm. The resulting pastes were independently ground in an SDY200 three-roll mill (Buhler) in three passes at 25°C (first pass at 8 bar, second and third pass at 11 bar).

The viscosity values listed in table. 1A-B were independently measured on each UV-visible gravure ink using a Haake Roto Visco 1 rotary rheometer (C20/0.5°; at 40°C and 200 s ^-1 ).

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Comments for Tables 1A-B ^a : Comparative Paint C2 contained a total amount of active diluent in the form of propoxylated glycerol triacrylate: 8 wt.% (from EBECRYL® 53) + 4.2 wt.% (from

EBECRYL® 3608).

^b : Comparative paint C3 contained a 6.3 wt% amount of active diluent in the form of trimethylolpropane triacrylate (from EBECRYL® 1606).

^c : Comparative paint C4 contained a total amount of active diluent in the form of propoxylated glycerol triacrylate: 8 wt.% (from EBECRYL® 53) + 11.2 wt.% (from EBECRYL® 438).

^d : the paint according to the present invention E3 contained an amount of active diluent in the form of trimethylolpropane triacrylate 1.08 wt.% (from the company EBECRYL® 1606).

^e : Comparative paint C8 contained a total amount of active diluent in the form of propoxylated glycerol triacrylate: 8 wt.% (from EBECRYL® 53) + 4.2 wt.% (from EBECRYL® 3608).

f: Comparative paint C9 contained an amount of active diluent in the form of trimethylolpropane triacrylate of 6.3 wt.% (from EBECRYL® 1606).

Cleanability test of radiation-curable gravure inks

Even though the radiation-curable intaglio inks of the present invention have been designed to be printed by an intaglio printing process in which any excess of said ink is removed from the plate using a resin cylinder to remove the excess ink, and in which said resin The excess paint removal cylinder is cleaned with an alkaline aqueous wiping solution in combination with one or more mechanical means, such as brushes and/or pads, and the detergency test is performed as described hereinafter.

± 2 mg of each of the UV-visible gravure inks from Tables 1A-B was independently applied to a PVC plate as a disc layer of approximately 15 mm in diameter.

Five drops of a standard aqueous rubbing solution containing 0.8 wt% caustic soda and 0.5 wt% sulphated/sulfonated castor oil were added dropwise onto the paint disk layer. Mixing the paint and rubbing solution was done by rubbing the mixture with your fingertips for approximately 30 s.

The mixture of at least partially emulsified UV-visible gravure inks in an aqueous wipe solution was then independently removed from the PVC plate by gently cleaning the plate with a cloth. The platen was visually inspected for the presence or absence of any remaining layer of UV-visible gravure ink.

The cleaning properties for each of the UV-visible gravure inks are presented in Tables 1A-B, with the combination of complete emulsification and complete removal of the corresponding UV-visible gravure ink from the platen of PVC was scored as a positive result (expressed as D), and the lack of a combination of complete emulsification and/or complete removal of the respective UV-visible gravure ink from the PVC plate was scored as a negative result (expressed as H) .

As shown in table. 1A-B, all comparative inks C1-C9 failed the washability test, either due to lack of or poor emulsification of the ink with the aqueous wipe solution, and/or due to residual ink on the PVC plate when gently wiped with a cloth.

On the one hand, the absence of polyester acrylate fatty acid oligomer in comparative paints containing high molecular weight acid-modified alkyd surfactant (C1-C4), or the absence of polyester acrylate fatty acid oligomer in comparative paints containing alkylbenzenesulfonic acid surfactant (C6-C9 ) has resulted in poor performance of UV-visible gravure inks. On the other hand, the absence of high molecular weight acid-modified alkyd surfactant in the comparative fatty acid polyester acrylate oligomer (C5) ink also resulted in poor performance of the UV-visible gravure ink.

The UV-visible gravure ink of the present invention (E1-E5) exhibited good shelf life/shelf life since it did not show any crust formation on its surface during storage. (for at least 30 days).

_____________________ Table 1A

Ingredients C1 C2 ^a NW ¹ ' " C5 El E2 E3 ^d E4 Quantity [wt. %] EBECRYL® 1657 (APPEH) Polyester acrylate fatty acid oligomer: polyester tetraacrylate stearic/palmitic acid 28 28 10 4.8 EBECRYL® 450 (APPEH) Polyester acrylate fatty acid oligomer: polyester hexaacrylate stearic/palmitic acid 36 GENOMER* 43 16 (RAHN) Urethane acrylate oligomer: aliphatic polyester urethane triacrylate oligomer 28 EBECRYL® 3608 (APPECH) Epoxy Acrylate Oligomer: Bisphenol-A based epoxy diacrylate oligomer diluted in 15% propoxylated glycerol triacrylate 28 EBECRYL® 1606 (APPECH) Epoxy diacrylate oligomer: bisphenol-A based epoxy diacrylate oligomer diluted in 20-25% trimethylolpropane triacrylate (CAS number: 55818-57-0 to 15625-89-5) 28 4.8 EBECRYL® 438 (APPECH) Chlorinated polyester oligomer, diluted with 40% propoxylated glycerol triacrylate 28 EBECRYL® 53 (APPEH) Active diluent: propoxylated glycerol triacrylate (CAS number: 52408-84-1) 8 8 8 8 8 8 8 14.2 High molecular weight acid modified alkyd surfactant (more details in this document above) 10 10 10 10 - 10 10 9.5 10 Omnirad 819 (IGM) Photoinitiator: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (CAS number: 162881-26-7) 8 8 8 8 8 8 8 7.6 8 Omyalite 50 (Omya) Filler: Calcium Carbonate (CAS No.: 1317-65-3) 32 32 32 32 42 32 50 45.7 32 Finntalc Ml5 (Mondo Mineralis) Filler: talc (Mg-silicate) (CAS number: 14807-96-6) 3 3 3 3 3 3 3 2.9 3 Carnauba wax T1 + TZ (A. Smit Trading AG) Wax: Carnauba wax (AS number C: 8015-86-9) 4 4 4 4 4 4 4 3.8 4 Heliogen Blue D 7079 (BASF) Pigment: C.I. Pigment Blue 15:3, phthalocyanine (147-14-8) 5 5 5 5 5 5 5 4.8 5 Florstab UV-1 (Kromachem) F-stabilizer 2 2 2 2 2 2 2 1.9 2 Viscosity [Pa“s] 32.5 26.4 18.3 24.6 27.2 31.2 33.6 24.5 10.7 Cleaning power N N N N N d d d d

Table 1B

Ingredients C5 C6 C7 C9^r E5 Quantity [wt. %] EBECRYL® 1657 (APpech) Polyester acrylate fatty acid oligomer: polyester tetraacrylate stearic/palmitic acid 28 28 GENOMER* 43 16 (RAHN) Urethane acrylate oligomer: aliphatic polyester urethane triacrylate oligomer 28 EBECRYL® 3608 (APpech) Epoxy acrylate oligomer: fatty acid modified epoxy acrylate oligomer diluted in 15% propoxy glycerol triacrylate 28 EBECRYL® 1606 (APpech) Epoxy diacrylate oligomer: bisphenol-A based epoxy diacrylate oligomer diluted in 20-25% trimethylolpropane triacrylate (AS number C: 55818-57-0 to 15625-895) 28 EBECRYL® 438 (APpech) Chlorinated polyester oligomer, diluted with 40% propoxylated glycerol triacrylate 28 EBECRYL® 53 (APpech) Active diluent: propoxylated glycerol triacrylate (CAS number: 52408-84-1) 8 8 8 8 8 8 Zephrym^1M3300B (Croda) alkylbenzenesulfonic acid surfactant: salt -

Claims

2-amipopropane dodecylbenzenesulfonic acids (CAS number: 84961-74-0, HLB: 11.4)

Omnirad 819 (IGM) Photoinitiator: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (CAS number: 162881-26-7) 8 8 8 8 8 8

Omyalite 50 (Omya) Filler: Calcium Carbonate (CAS No.: 1317-65-3) 42 36 36 36 36 36

Finntalc М15 (Mondo Mineralis) Filler: Talc (Mg-silicate) (CAS No.: 14807-96-6) 3 3 3 3 3 3

Carnauba wax T1 + TZ (A. Smit Trading AG) Wax: Carnauba wax (CAS number: 8015-86-9) 4 4 4 4 4 4

Heliogen Blue D 7079 (BASF) Pigment: C.l. Pigment Blue 15:3, phthalocyanine (147-14-8) 5 5 5 5 5 5

Florstab UV-1 (Kromachem) UV stabilizer 2 2 2 2 2 2

Viscosity [Pa*s] 27.2 35.8 55.0 35.5 27.6 38.4

Cleaning power N N N N N d

Fracture testing of printed and cured gravure inks

Even though the radiation-curable intaglio inks of the present invention have been designed to be printed by an intaglio printing process in which any excess of said ink is removed from the plate using a resin cylinder to remove the excess ink, and in which said resin the cylinder to remove excess ink is cleaned with an alkaline aqueous wiping solution in combination with one or more mechanical means such as brushes and/or pads, a fracture test is carried out on samples that have been printed using an intaglio printing process in which any excess of said ink is removed from a plate using paper.

Radiation-curable gravure inks E1 and E5 were independently printed using an Ormag gravure proofing press. An appropriate radiation-curable intaglio ink was applied to the intaglio platen using a polymer hand-held ink roller. Excess radiation-curable intaglio inks were manually removed with paper. The intaglio ink composition was printed on a standard cotton paper substrate used for banknote applications (Cotton Banknote Paper from Louisenthal; 17 cm x 14.5 cm), the intaglio plate being heated to 60°C. The printed samples were cured by irradiation with a Ga-In and Hg lamp (2 x 15 A; 2 x 150 W/cm) from IST (two passes at 100 m/min).

A square sample measuring 6.5 cm x 6.5 cm was taken from each substrate printed using the ink compositions (E1 and E5) described in Table 1. 1A-B.

Each square sample was individually rolled so that the printed layer faced the inside of the roll. The sample was placed in the metal cylinder of the IGT Reprotest fracture tester and crushed. The dented square sample was removed from the cylinder. It was unfolded, folded along the next edge of the square sample clockwise and the breaking procedure was repeated. The same procedure was applied sequentially along the other two edges of the square specimen.

Folding and crumpling along each of the four edges of the square sample was repeated with the printed layer facing the environment.

The square sample was unrolled and the gravure ink layer was rated: the substrate containing the layer made of the E1 radiation-curable gravure ink had a score of 5, and the substrate containing the layer made of the E5 radiation-curable gravure ink had a score of 5. had a score of 3-4, where 5 means no change in the paint layer visible to the naked eye; 4 means little change; 3 means significant change <50%, 2 means large change >50% and 1 means paint layer has disappeared.

The UV-visible gravure inks of the present invention (E1 and E5) exhibited good durability on the gravure printing press as they did not show any crusting over at least one night.

CLAIM

1. A radiation-curable gravure ink containing:

a) from 10 to 60% by weight of one or more radiation-curable compounds, wherein at least one of the one or more radiation-curable compounds is a polyester (meth)acrylate fatty acid oligomer;

b) from 2 to 20 wt.% one or more photoinitiators selected from the group consisting of Norrish type I photoinitiators, Norrish type II photoinitiators and mixtures thereof;

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c) from 5 to 12 wt.% high molecular weight acid-modified alkyd surfactant and/or alkylarene sulfonic acid surfactant;

d) from 10 to 55% by weight of one or more fillers or diluents selected from the group consisting of carbon fibers, talcs, micas, wollastonites, calcined clays, white clays, kaolins, carbonates, silica and silicates, sulphates, titanates, titanium dioxides, aluminum oxide hydrates, colloidal silicon dioxides, montmorillonites, graphites, anatase, rutiles, bentonites, vermiculites, zinc white, zinc sulfides, wood flour, quartz flour, maize starches, natural fibers, synthetic fibers and combinations thereof, and mass the percentage is calculated based on the total weight of the radiation-curable intaglio ink, and the viscosity of the radiation-curable intaglio ink is 10 to 50 Pa-s at 40°C and 200 s ^-1 .

2. The radiation-curable gravure ink according to claim 1, wherein the molecular weight of the high molecular weight acid-modified alkyd surfactant is from 3000 to 20000, preferably from 5000 to 15000.

3. The radiation-curable gravure ink of any one of the preceding claims, wherein the fatty acid polyester (meth)acrylate is a polyester tetraacrylate fatty acid oligomer or a polyester hexaacrylate fatty acid oligomer.

4. The radiation-curable intaglio ink according to any of the preceding claims, wherein the polyester (meth)acrylate fatty acid oligomer contains saturated fatty acid residues, preferably saturated fatty acid residues with 14-20 carbon atoms, even more preferably with 16 -18 carbon atoms.

5. The radiation-curable gravure ink of any one of the preceding claims, wherein the one or more other radiation-curable compounds of the one or more radiation-curable compounds are (meth)acrylate monomer active diluents selected from a group consisting of mono(meth)acrylate monomers, di(meth)acrylate monomers, tri(meth)acrylate monomers, tetra(meth)acrylate monomers and mixtures thereof.

6. The radiation-curable gravure ink of any one of the preceding claims, wherein the one or more other radiation-curable compounds of the one or more radiation-curable compounds are selected from the group consisting of urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers and mixtures thereof.

7. The radiation-curable gravure ink of any one of the preceding claims, wherein the alkyl arenesulfonic acid surfactant is a (C ₁ -C ₁₄ -alkyl)arenes sulfonic acid, preferably an ammonium salt or an alkyl-substituted ammonium salt (C ₄ -C ₁₄ -alkyl)arenesulfonic acids, more preferably an ammonium salt or an alkyl-substituted ammonium salt of a (C ₄ -C ₁₄ -alkyl)benzenesulfonic acid.

8. The radiation-curable intaglio ink of any one of the preceding claims, further comprising from 1 to 7% by weight of one or more waxes, preferably selected from the group consisting of microcrystalline waxes, paraffin waxes, polyethylene waxes, fluorocarbon waxes, polytetrafluoroethylene waxes, Fischer-Tropsch waxes, silicone fluids, beeswaxes, candelilla waxes, montane waxes, carnauba waxes and mixtures thereof, the percentage by weight being calculated based on the total weight of the radiation-curable intaglio ink.

9. The radiation-curable gravure ink of any one of the preceding claims, further comprising one or more coloring components selected from the group consisting of permanent color pigments, dyes, and mixtures thereof, preferably selected from the group consisting of organic pigments with permanent color, permanent color inorganic pigments and mixtures thereof.

10. The radiation-curable intaglio ink of any one of the preceding claims, further comprising one or more machine-readable materials, preferably selected from the group consisting of magnetic materials, luminescent materials, electrically conductive materials, infrared absorbing materials, and mixtures thereof.

11. A design or image made from radiation-curable intaglio ink according to any one of claims 1 to 10.

12. A protected document containing a drawing or image according to claim 11.

13. A method for producing a drawing or image, wherein said method includes:

a) applying the radiation-curable intaglio ink according to any one of claims 1 to 10 onto the engraved intaglio printing plate,

b) removing any excess radiation-curable gravure ink using a polymer cylinder to remove excess ink and cleaning said poly-

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