RU2575644C2 - Application of aryl- or heteroaryl-substituted dithiolene metal complexes as ir-absorbers - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: claimed invention relates to application of dithiolene metal complexes, namely compounds of formulae (1)-(19), structure of which is given in the invention formula, as colourless IR-absorbers for anti-counterfeit printing. Also claimed are: application of mixture for anti-counterfeit printing, applications of compounds and mixture in printing paint composition, anti-counterfeit document (versions).

EFFECT: compounds demonstrate high resistance with respect to chemical reagents and solvents, without losing their other advantages, which makes it possible to apply them as IR-absorbers for anti-counterfeit printing.

12 cl, 1 tbl, 20 ex

Description

The present invention relates to the field of metal complexes of dithiolenes with aryl-substituted imidazolidin-2-chalcogenone-4,5-dithionic ligands, which are colorless IR absorbers, more specifically, the use of the below-described aryl-substituted dithiylene metal complexes as colorless IR absorbers for printing and security documents containing them.

There is a significant need for colorless or at least barely colored IR absorbers in a wide range of applications, such as counterfeit printing (banknotes, credit cards, ID cards, passports, etc.) that are invisible and / or read in IR barcode radiation, laser welding of plastics, curing of protective coatings using IR sources, drying and curing of printed images, fixing toner on paper or plastics, optical filters for PDP (plasma panels), laser Black marking, for example, on paper or plastics, heating of plastic preforms, application for thermal protection, etc.

It is known to use a large number of organic and inorganic substances belonging to different classes of compounds and having a wide variety of structures as IR absorbers. Despite such a large number of known classes of compounds and structures, obtaining products with a complex profile of properties often encounters difficulties. There is a continuing need for IR absorbers that are “colorless” (that is, having the lowest possible coloration), which at the same time satisfy the technical requirements for stability (chemical stability, heat resistance and / or light resistance).

A special field of application for colorless IR absorbers is printing inks, which are used to print currency and other protected documents, also called "counterfeit-proof printing". Typical anti-counterfeit printing processes are processes that use a paint composition designed to selectively absorb radiation in the optical infrared spectrum, while being transparent in other areas. Counterfeit-proof IR absorbers are available, for example, from American Dye Source, but almost all of them have a noticeable absorption in the UV / visible spectral range (400 to 700 nm).

US 2008/0241492 describes an intaglio printing ink used in an anti-counterfeit printing process, wherein said ink contains a polymeric organic binder and an IR absorbing material containing transition element atoms or ions in which the IR absorption is a consequence of electronic transitions in the d-shell of the transition element. Suitable transition elements are Ti, V, Cr, Mn, Fe, Co, Ni and Cu. In a suitable embodiment, the IR absorbing material is glass in which coordination of transition element ions with phosphate and / or fluoride anions present in the glass is observed. In another suitable embodiment, the IR absorbing material is an IR absorbing atom or transition element ion bonded to a polymer binder material in a paint. In particular, the IR-absorbing material is an IR-absorbing complex of an atom or ion of a transition element with a binding site present in the polymer, for example, a complex of copper (II) with organic thiourea dissolved in a polymer binder.

U.S. Pat. or dyes based on azulene square acid, as well as containing a solvent and a binder.

International patent application WO 2007/091094 describes an article with an image that contains a substrate, at least a portion of which is coated with a latent image, where said latent image contains a described IR-absorbing compound, for example, green pigment Pigment Green 8, which gives a non-intense coloring hidden image. The described IR-absorbing compounds still have a noticeable absorption in the UV / visible spectral range.

International patent application WO 2007/132214 describes a composition comprising a paint and an IR absorbing material comprising a metal, a metal salt, a metal oxide or a metal nitride, wherein the metal is, in particular, selected from elements of 4, 5 periods or lanthanides. Also described is a product containing a substrate with an IR absorbing material deposited thereon forming a latent image, and a method for manufacturing such products by applying a composition comprising such an IR absorbing material to a substrate.

M. Area et al. Are described in an article by J. Chem. Soc., Dalton Trans. 1998, 3731-3736 metal-dithiolene (see Scheme 1), belonging to the general class [M (R, R'timdt) ₂ ] (M = Ni, Pd; (R, R'timdt) = monoanion of disubstituted imidazolidin-2 4,5-trithione; R and R '= ethyl or isopropyl). Since such metal dithiolenes exhibit strong π-delocalization, they can also be characterized by the aromatic resonance structure on the right:

Japanese Patent Applications JP 2003-262953 A, JP2004-045653 A and JP 2005-99755 A describe metal dithiolenes [M (R, R'timdt) ₂ ], where R and R 'are selected from unsubstituted and substituted alkyl, cycloalkyl and aryl groups.

M.S. Aragoni et al. Are described in an article by Eur. J. Inorg. Chem. 2003, 1939-1947 NIR dyes based on [M (R, R'timdt) ₂ ] metal dithiolenes, where R and R 'are selected, among others, from unsubstituted and substituted aryl groups.

International patent application WO 2008/086931 describes the use of dithiolene metal complexes [M (L) ₂ ], where L is the monoanion of a disubstituted imidazolidin-2-chalcogenone-4,5-dithion and the chalcogen is O or S, as colorless IR - absorbers. Since aryl substituted compounds are described in very general terms, there is no detailed interpretation regarding these compounds. In particular, in all examples, nitrogen atoms carry only unsubstituted and substituted alkyl and alkenyl groups. Especially in terms of colorlessness, the compounds described in WO 2008/086931 are superior to previously known IR absorbers, while at the same time meeting other technical requirements, such as good light fastness or good heat resistance when introduced into plastics (for example, for laser welding). However, for high-tech applications, the dithiylene metal complexes described in WO 2008/086931 still need to improve stability characteristics, for example resistance to chemicals and boiling water. Such characteristics are important, in particular for applications in the field of anti-counterfeiting printing.

The inventors of the present invention unexpectedly found that dithiolene metal complexes [M (L) ₂ ], in which L is selected from monoanions of a disubstituted imidazolidin-2-chalcogenone-4,5-dithion, and the chalcogen is S, with N-aryl substituents instead of N -alkyl substituents, demonstrate high resistance to chemicals and solvents, without losing their other advantages, such as colorlessness, good light resistance and good heat resistance. They can be advantageously used as infrared absorbers for printing with anti-counterfeiting and for laser welding of plastics. Due to their unique consumer properties, they are particularly suitable as IR absorbers for printing with counterfeit protection, especially for banknotes.

The above technical result is achieved by representing the first object of the invention by the use of compounds selected from the group including compounds of formulas (1) - (19)

or mixtures thereof,

as colorless IR absorbers for printing with anti-counterfeiting.

The second object of the invention is the use of a mixture containing at least one compound of the above formulas (1) to (19), and at least one other IR absorber other than the compounds of formulas (1) to (19), for counterfeit printing, preferably for printing counterfeit banknotes.

A third object of the invention is the use of the compounds of the above formulas (1) to (19) in a print composition for printing with anti-counterfeiting printing to improve the resistance characteristics of the resulting print, in particular to increase the resistance to chemicals, solvents and / or boiling water.

A fourth aspect of the invention is the use of the mixture according to the second aspect of the invention in the composition of a printing ink for printing with anti-counterfeiting, to improve the resistance characteristics of the resulting print, in particular to increase resistance to chemicals, solvents and / or boiling water.

A fifth aspect of the invention is a security document containing a substrate and at least one compound of the above formulas (1) to (19) or a mixture of the above second aspect of the invention.

A sixth aspect of the invention is a security document obtained by a printing process in which a printing ink composition comprising

a) at least one compound of the above formulas (1) to (19), or a mixture according to the above second object of the invention,

b) a polymeric binder,

c) a solvent

d) optionally at least one dye, and

e) optionally at least one additional additive.

In this case, the used ink composition contains the indicated components a) -e) in the following quantities:

a) 0.0001-25% by weight, preferably 0.001-15% by weight, in particular 0.01-5% by weight, based on the total weight of the composition,

b) 5-74% wt., preferably 10-60% wt., more preferably 15-40% wt., based on the total weight of the composition,

c) 1-94.9999% by weight, preferably 5-90% by weight, in particular 10-85% by weight, based on the total weight of the composition,

d) 0-25% wt., preferably 0.1-20% wt., in particular 1-15% wt., based on the total weight of the composition,

e) 0-25% wt., preferably 0.1-20% wt., in particular 1-15% wt., based on the total weight of the composition,

moreover, the sum of components a) - e) is always 100%.

The protected document for the sixth object of the invention is selected from a banknote, passport, check, voucher, identity card or card for money transfer, stamp and excise stamp.

The technical result of the invention is, in particular, to the fact that the above compounds, indicated by the numbers (1) to (19), exhibit the following properties:

- good resistance to chemical reagents, in particular resistance to decolorization with hypochlorite and resistance to solvents (such as toluene, acetone or dichloromethane),

- good resistance to boiling water,

- good light fastness,

- colorless (i.e., the minimum absorption in the UV / visible region of the spectrum (from 400 to 700 nm))

- good heat resistance,

- good compatibility with various compositions, in particular with compositions of printing ink used in printing with anti-counterfeiting, and with compositions of thermoplastics used in laser welding.

For a definition and description of the sustainability requirements for printing banknotes, see, for example, Chemical and Physical Resistance in Extract of the ANNEX 13 of the Technical Specification for Euro banknote production (European Central Bank; July 2004).

Suitable other IR absorbers are in principle all known classes of IR absorbers compatible with the compounds of the above formulas (1) to (19). Preferred other IR absorbers are selected from polymethines, phthalocyanines, naphthalocyanines, quinone diimmonium salts, amine salts, rylene, inorganic IR absorbers and mixtures thereof. Other polymethine IR absorbers are preferably selected from cyanines, squaraines, croconaines and mixtures thereof. Other inorganic IR absorbers are preferably selected from indium / tin oxide, antimony / tin oxide, lanthanum hexaboride, tungsten bronzes, copper salts, etc.

IR absorbers in general can be used at a concentration of 10 ppm or more. up to 25%, preferably from 100 ppm up to 10%, depending on the chosen field of application.

 The IR absorbers of formulas (1) to (19) described above and mixtures of IR absorbers are particularly suitable for printing with counterfeit protection.

Counterfeit printing is an area related to the printing of products such as currency, passports, tamper evident labels, share certificates, postage stamps, identity cards, etc. The main goal of anti-counterfeiting printing is to prevent counterfeiting, tampering or tampering.

In the field of automatic banknote processing, IR absorption plays an important role. Most of the currency in circulation has not only visual color images, but also distinctive features that are detected only in the infrared part of the spectrum. In general, such IR distinctive features are intended for use by equipment for automatic processing of banknotes, in bank equipment and automatic retail outlets (ATMs, automatic trading machines), for recognition of certain banknotes and confirmation of their authenticity, in particular for recognizing them from fakes made on color copy machines.

All protected documents must have good stability and durability. In the case of banknotes, these requirements are extremely high, since banknotes are exposed to the most difficult conditions of use by the population - their material is subjected to stresses when folding, creasing, etc., they are subject to abrasion, exposed to the external environment, exposed to physiological fluids such as sweat wash, dry, iron, etc .; and after all these influences, they should be as readable as in their original state. In addition, it is essential that these documents, in spite of everything, should have a reasonable lifetime, ideally several years, regardless of the impact of the above conditions. During this time, documents and paint on them (including invisible secret marks) must be resistant to fading or discoloration. Therefore, any printing ink used for printing with anti-counterfeiting printing should, after drying, be resistant, resistant to water, resistant to various chemicals and flexible. In addition, since certain states are moving away from using paper as a material for banknotes, the applied ink compositions should be applicable to both plastics and paper. The inventors of the present invention have found that the compounds of the above formulas (1) to (19), due to their unique consumer properties, are particularly suitable for printing ink compositions which are used for printing with counterfeit protection, in particular for banknotes.

For counterfeit printing, an IR absorber is added to the ink composition. Suitable printing inks are water, oil based or solvent based printing inks, pigment or dye based, for inks, flexographic printing, screen printing, gravure printing, offset printing, laser printing or letterpress printing, and for use in electrophotography . Inks for these printing processes typically contain solvents, binders, and various additives such as plasticizers, antistatic agents, or waxes. Printing inks for offset printing and letterpress printing typically take the form of highly viscous paste-like printing inks, while printing inks for flexographic printing and gravure printing typically have the form of liquid printing inks with a relatively low viscosity.

In the context of the present invention, the term "printing ink" also encompasses compositions which, in addition to at least one IR absorber of the above formulas (1) to (19), contain a dye. The term "printing ink" also encompasses printing inks that do not contain dyes.

Suitable components for printing inks are commonly used and well known to those skilled in the art. Examples of such components are described in Printing Ink Manual, fourth edition, Leach R. H. et al. (eds.), Van Nostrand Reinhold, Wokingham, (1988). Details of printing inks and their compositions are also described in "Printing lnks" -Ullmann′s Encyclopedia of Industrial Chemistry, Sixth Edition, 1999 Electronic Release. The composition of IR absorbing gravure printing inks is described in US Patent Application US20080241492 A1. The texts of the above documents are hereby incorporated by reference.

The compounds of the above formulas (1) to (19) are present in the composition of the printing ink in a dissolved form or in solid form (in a finely divided state).

Suitable polymeric binders b) for the above ink composition are selected, for example, from natural resins, phenolic resins, phenol-modified resins, alkyd resins, polystyrene homo and copolymers, terpene resins, silicone resins, polyurethane resins, urea-formaldehyde resins, melamine resins, polyamide resins, polyacrylates, polymethacrylates, chlorinated resins, resins based on vinyl esters, acrylic resins, epoxy resins, nitrocellulose, hydrocarbon resins, cellulose acetate and mixtures thereof.

The above ink composition may also contain components that form a polymeric binder during the curing process. Thus, the ink composition of the present invention may also be curable by exposure to energy, for example, curable by UV radiation or electron beam irradiation. In this embodiment, the binder contains one or more curable monomers and / or oligomers. Suitable formulations are known in the art and can be found in standard manuals such as the Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints series, published in 7 volumes in 1997-1998 by John Wiley & Sons jointly with SITA Technology Limited.

Suitable monomers and oligomers (also called prepolymers) include epoxy acrylates, acrylated oils, urethane acrylates, polyester acrylates, silicone acrylates, acrylated amines and acrylic saturated resins. Further details and examples are provided in Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints, Volume II: Prepolymers & Reactive Diluents, edited by G Webster.

If a curable polymeric binder is used, it may contain reactive diluents, i.e. monomers that play the role of a solvent and which, when cured, are incorporated into the polymer binder. Reactive monomers are usually selected from acrylates or methacrylates, and they can be monofunctional or multifunctional. Examples of multifunctional monomers include poly-ester acrylates or methacrylates, polyol acrylates or methacrylates, and poly-ester acrylates or methacrylates.

In the case where the ink composition is cured by UV radiation, it is usually necessary to include at least one photoinitiator to initiate the curing reaction of the monomers when exposed to UV radiation. Examples of suitable photoinitiators can be found in standard manuals such as Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints, Volume III, Photoinitiators for Free Radical Cationic and Anionic Polymerisation, 2nd edition, by JV Crivello & K Dietliker, edited by G. Bradley, published in 1998 by John Wiley & Sons in association with SUA Technology Limited. It may also be advantageous to incorporate the sensitizer together with a photoinitiator to provide effective cure.

Suitable solvents contained in the above ink composition are selected from water, organic solvents, and mixtures thereof. In the context of the present invention, reactive monomers, which also act as solvents, are considered part of the above, and which is a binder, component b).

Examples of solvents include water, alcohols, for example ethanol, 1-propanol, 2-propanol, ethylene glycol, propylene glycol, diethylene glycol and ethoxypropanol; esters, for example ethyl acetate, isopropyl acetate, n-propyl acetate and n-butyl acetate; hydrocarbons, for example toluene, xylene, mineral oils and vegetable oils, and mixtures thereof.

Suitable dyes d) which may be contained in the above ink composition are some commonly used inks, and in particular commonly used pigments. The term "pigment" in the context of the present invention is used comprehensively to refer to all pigments and fillers, examples of which are colored pigments, white pigments and inorganic fillers. These include inorganic white pigments, such as titanium dioxide, preferably in the form of rutile, barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, antimony trioxide, lithopones (zinc sulfide + barium sulfate), or colored pigments, examples of which are iron oxides , carbon black, graphite, yellow zinc, green zinc, ultramarine, manganese black dye, antimony black, manganese violet dye, Paris blue or Schweinfurt greens. In addition to the inorganic pigments, the printing ink composition of the present invention may also contain organic colored pigments, examples of which are sepia, gummigut, brown vandake, toluidine red, paranitroaniline red, Hansa yellow, indigo, azo dyes, anthraquinone and indigo dyes, as well as dioxazine , quinacridone, phthalocyanine, isoindolinone and metal complex pigments. Synthetic white pigments with air inclusions to enhance light scattering, such as Rhopaque® dispersions, can also be used. Suitable fillers are, for example, aluminosilicates such as feldspars, silicates such as kaolin, talc, mica, magnesite, alkaline earth metal carbonates such as calcium carbonate, in the form of, for example, calcite or chalk, magnesium carbonate, dolomite, alkaline earth metal sulfates such as calcium sulfate, silicon dioxide, etc.

Suitable additives (possible component e) in the above ink composition) are selected from plasticizers, waxes, desiccants, antistatic agents, chelators, antioxidants, stabilizers, adhesion promoters, surfactants, flow improvers, defoamers, biocides, thickeners, etc. D., and their combinations.

These additives serve, in particular, to fine-tune the performance of printing inks, examples of which are adhesion, abrasion resistance, drying speed or sliding.

The above ink composition is advantageously prepared in a conventional manner, for example by mixing individual components. As indicated previously, the infrared absorber of the above formulas (1) to (19) is present in the printing ink compositions in dissolved or finely divided solid form. Additional dyes can be used in the ink composition of the present invention or as a separate coloring preparation. In the case of the use of additional dyes in the form of a separate preparation, the application time of the printing ink composition of the present invention is usually not significant. For example, the ink composition of the present invention can be applied first, and then printed on top of it with conventional inks. But you can also use the reverse order or, alternatively, apply the composition of the printing ink of the present invention in the form of a mixture with conventional printing inks. In each case, prints are visible when using suitable light sources.

Before applying the above ink composition, a primer may be used. For example, a primer is applied to improve adhesion to the substrate. You can also apply additional varnishing, for example, in the form of a coating to protect the printed image. Additional varnishing can also be applied for aesthetic reasons or to improve performance. For example, suitable additional varnishing can be used to change the surface roughness of the substrate, electrical characteristics or properties associated with condensation of water vapor. Varnishing is usually applied during the printing process by a varnishing system in a printing press used for printing with the printing ink composition of the present invention.

The above ink composition is also suitable for use in multilayer materials. Multilayer materials consist, for example, of two or more layers of a plastic film, such as a polyolefin film, a metal foil or a metallized plastic film, which are bonded to each other, for example, by lamination or using suitable laminating adhesives. Such composites may also include other functional layers, such as barrier layers, odorless or water vapor.

The above IR absorbers of the above formulas (1) to (19) and mixtures of IR absorbers are also well suited for laser welding of plastics.

Laser welding is preferably carried out using an ND: YAG laser with a wavelength of 1064 nm or using a diode laser with a wavelength of 980 nm or 940 nm. The concentration of the IR absorber of the above formulas (1) to (19) or mixtures of IR absorbers is, for example, 5-500 ppm, preferably 10-200 ppm.

During laser welding, plastic elements are welded to each other. The plastic elements subjected to splicing can be of any shape. For example, at least one of the plastic elements may be a film.

The dithiolenes of the above formulas (1) to (19) used in the present invention are suitable for welding transparent or at least translucent plastic materials. The plastic materials used may be colorless or dyed. In principle, plastic elements intended for welding may consist of the same polymer or of different polymers. Preferably, the plastic elements to be welded are selected from thermoplastic polymers. However, it is also possible that none of the plastic elements intended for splicing is made of thermoplastic; however, it is necessary to cover at least one part with a thermoplastic containing at least one compound of the above formulas (1) to (19).

The plastic elements used for laser welding preferably consist or contain at least one polymer selected from polyolefins, polyolefin copolymers, polytetrafluoroethylene, ethylene tetrafluoroethylene copolymers, polyvinyl chlorides, polyvinylidene chlorides, polyvinyl alcohols, polyvinyl esters, polyvinyl polyethylenes, polyvinyl polyethylenes, polyvinyl polyethylenes, polyvinyl polyethylenes, polyvinyl polyethylenes, polyvinyl polyethylenes, polyvinyl polyethylenes, polyvinyl polyvinyl esters , polyimides, polycarbonates, blends of polycarbonates, polyesters, blends of polyesters, poly (meth) acrylates, poly (meth) acrylate-styrene copolymers, poly ( em) acrylate-polyvinylidene diftoridnyh mixtures, polyurethanes, polystyrenes, styrenic copolymers prostoefirnyh polymers, polyether ketones and polysulfones and mixtures thereof.

Preferred are matrix polymers from the group of polyolefins, polyolefin copolymers, polyvinyl alkanes, polyamides, polycarbonates, polycarbonate-polyester blends, polycarbonate-styrene copolymers, polyesters, blends of polyesters, poly (meth) acrylates, poly (meth) acrylate-styrene copolymers ) acrylate-polyvinylidene difluoride mixtures, styrene copolymers and polysulfones and mixtures thereof.

Particularly preferred polymers are transparent or at least translucent. Examples thereof include: polypropylene, polyvinyl butyral, nylon- [6], nylon- [6,6], polycarbonate, polycarbonate-polyethylene terephthalate mixtures, polycarbonate-polybutylene terephthalate mixtures, polycarbonate-acrylonitrile / styrene / acrylonitrile copolymers, polycarbonate-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile-acrylonitrile / styrene copolymers, polymethyl methacrylate-acrylonitrile / butadiene / styrene copolymers (MABS), polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, high impact polymethyl methacrylate, polybutyl acrylate, polymethyl methacrylate-polyvinylidene mixture Nitrile / butadiene / styrene copolymers (ABS), styrene / acrylonitrile copolymers (SAN), polyphenylene sulphone, and mixtures containing 2 or more (e.g., 2, 3, 4, 5) of the polymers listed above.

Suitable polymer preparations for laser welding contain:

A) a thermoplastic matrix polymer suitable for molding plastic parts,

B) at least one compound of the general formula (I) above,

C) optionally, at least one additional additive.

Such suitable polymer preparations for laser welding are also encompassed by the present invention and can be used to produce fusible plastic parts using laser irradiation whose wavelength is outside the visible range.

Polymer preparations for laser welding can be conveniently produced using well-known extrusion or mixing processes. Components B) and, if present, components C) can be mixed from the very beginning in a weight ratio corresponding to the target final concentration, with matrix polymer A) (direct mixing), or you can choose to knowingly high concentrations of components B) and, if present , components C), and the resulting concentrate (masterbatch) is then diluted with matrix polymer A) during the production of parts for welding.

Suitable additives C) are UV stabilizers, antioxidants, plasticizers, etc.

In addition, polymer preparations for laser welding may contain as an additive at least one dye to impart the desired shade, in particular transparent organic pigments, and in particular paints, for example C.I. yellow pigment. Pigment Yellow 138, 139, 147, 183, 185 192 and 196, orange pigment C.I. Pigment Orange 70, red pigment C.I. Pigment Red 149, 178 and 179, 181, 263, purple pigment C.I. Pigment Violet 19 and 29, blue pigment C.I. Pigment Blue 15, 15: 1, 15: 3 and 15: 4, green pigment C.I. Pigment Green 7 and 36, yellow solvent C.I. Solvent Yellow 14, 21, 93, 130, 133, 145, 163, red solvent C.I. Solvent Red 52, 135, 195, 213, 214 and 225, C.I. blue solvent. Solvent Blue 35, 45, 67, 68, 97, 104, 122, 132, C.I. purple solvent Solvent Violet 13, 46, 49, C.I. green solvent Solvent Green 3, 5 and 28, orange solvent C.I. Solvent Orange 47, 60, 86, 114, and 163, brown solvent C.I. Solvent Brown 35, 53, a as well as yellow dispersion C.I. Disperse Yellow 54, 87, 201, Disperse Orange C.I. 30, red dispersion C.I. Disperse Red 60 and Violet Dispersion C.I. Disperse Violet 57.

Another group of possible additives is additives that change the appearance, mechanical characteristics, or tactile characteristics, for example, matting agents, such as titanium dioxide, chalk, barium sulfate, zinc sulfide, fillers, such as nanosized silicon dioxide, aluminum hydroxide, clay and others layered silicates, glass fibers and glass balls.

The following examples illustrate the present invention without limiting its scope.

Examples

Example 1: Getting

This compound is known from Eur. J. Inorg. Chem. 2003, 1939-1947, and its preparation is described in this publication.

1,3-diphenyl-4,5-dioxo-imidazoline is reacted with metallic nickel and Lawsson's reagent while boiling in toluene. The use of chlorobenzene instead of toluene gives a higher yield. Maximum absorption (chloroform): 1023 nm.

Example 2: Getting

The reaction is carried out analogously to Example 1, with platinum chloride and Lawsson's reagent. Maximum absorption (chloroform): 1022 nm.

Example 3a: Preparation

2.0 parts of 1,3-di- (4-trifluoromethyl) phenylthiourea was dissolved in 130 parts of dichloromethane at 22 ° C. Over the course of 20 minutes, 0.99 parts of oxalyl chloride was added to the stirred solution at 22-25 ° C. After another hour of stirring, the solution was evaporated to dryness at 40 ° C. 1.7 parts of product were obtained (lit. Bioorganic Chemistry 17 (2009), 1437-1444).

Example 3b: Preparation

1.70 parts of the product from Example 3a, 0.115 parts of nickel metal and 1.70 parts of Lawson's reagent were heated to 130 ° C. under nitrogen in 130 parts of chlorobenzene. After 120 min, the solution was cooled to 25 ° C, the precipitate was filtered off, washed with water with a small amount of acetone. The maximum absorption of the product is observed at 1018 nm (chloroform).

Example 4a: Preparation

10.46 parts of 1,3-di (o-tolyl) thiourea were dissolved in 300 parts of dichloromethane at 25 ° C. Over the course of 20 minutes, 5.29 parts of oxalyl chloride were added to the stirred solution at 25 ° C. After another hour of stirring at 25 ° C, the solution was evaporated to dryness at 60 ° C: 13.3 parts of N, N'-di- (o-tolyl) -2-imino-1,3-thiazolidine-4,5- were obtained dione, which was added to 400 ml of methanol. The resulting mixture was heated at 65 ° C for 10 minutes. The resulting solution was cooled to 25 ° C, the precipitate was filtered off, washed with methanol and dried at 50 ° C in vacuo: 5.3 g of the product.

Example 4b: Preparation

3.79 parts of the product from Example 4a, 0.35 parts of metallic nickel and 5.1 parts of Lawsson's reagent were heated to 130 ° C. under nitrogen in 450 parts of chlorobenzene. After 120 min, the reaction solution was cooled to -10 ° C, the precipitate was filtered off, washed with ethanol with a small amount of acetone. Recrystallization from chlorobenzene gave black crystals. The maximum absorption of the product is observed at 1010 nm (chloroform).

Example 5a: Preparation

10.0 parts of 1,3-di (2,6-diisopropylphenyl) thiourea were dissolved in 220 parts of dichloromethane at 20 ° C. 3.33 parts of oxalyl chloride were added to the stirred solution at 21 ° C over 5 minutes. After another hour of stirring at 21 ° C, the solution was evaporated to 60 ° C to dryness: 12.1 parts of a solid were obtained, which was added to 400 ml of methanol. The resulting mixture was heated to 65 ° C for 10 minutes. The solution was filtered and cooled to 25 ° C. The precipitate was filtered off, washed with methanol and dried at 50 ° C in vacuo (oven): 9.9 g of a yellow product (mp. 211-212 ° C).

Example 5b: Preparation

2.07 parts of the product from Example 5a, 0.13 parts of metallic nickel and 1.96 parts of Lawsson's reagent were heated to 132 ° C. under nitrogen in 150 parts of chlorobenzene. After 180 minutes of reaction, the dark solution was cooled and evaporated to dryness at 50 ° C. For purification, the resulting crude product was recrystallized twice from butyl acetate. Dark brown crystals were separated by filtration. The maximum absorption of the product is observed at 1020 nm (tetrahydrofuran).

Application examples

Example A1 (Print)

11.9 parts of vinyl chloride, 2.1 parts of vinyl acetate, 10 parts of ethoxypropanol, 75.5 parts of methyl ethyl ketone and 1.0 parts of the product from Example 1 were jointly shaken with 150 g of glass beads for 30 minutes in a Skandex mixer. The resulting ink was applied to a contrast photo paper with a scraper (wet film thickness: 6 μm). The applied print is visually colorless, but is clearly visible in the infrared range when using an infrared viewing device (filter with a transmission limit of 715 nm). Lightfastness, resistance to chemicals and solvents - excellent.

Example A2 (Print)

By the methods described in Example A1, but using the IR absorber from Example 5b, a colorless print having excellent light fastness, which is clearly visible in the infrared range using an infrared viewing device, was similarly obtained. Resistance to chemicals and solvents is also excellent.

Example A3 (Print)

Prepared offset ink, absorbing infrared radiation containing 2.5% wt. (by weight solids) of the compound of Example 1. The paint was prepared in a 3-roller mill and contained 10% wt. adhesive varnish (CAS 68458-35-5, alkyd resin), 86.5% wt. selling offset varnish and 1% wt. a desiccant (based on CAS 136-52-7; cobalt bis (2-ethylhexanoate) and oleic acid, CAS 112-80-1). The resulting ink was applied by offset printing on paper used to print banknotes. The fingerprint is visually almost colorless, but is clearly visible in the IR range when using an infrared viewing device (filter with a transmission limit of 715 nm). The print shows excellent light fastness and very good resistance to all types of solvents, acids, bases, hydrogen peroxide, hypochlorite, sodium sulfite, boiling water, etc.

Example A4 (Print)

According to the methods described in Example A3, but with the use of 3.7% wt. (by weight of dry residue, adjusted for molecular weight) of the IR absorber from Example 5b, similarly received a colorless offset print having excellent light fastness, which is clearly visible in the infrared range when using an infrared viewing device. Good resistance to all types of solvents, acids, bases, hydrogen peroxide, hypochlorite, sodium sulfite, boiling water, etc. is shown.

Comparative Example (Printing)

According to the methods described in Example A3, but with the use of 2% wt. (based on dry solids weight, adjusted for molecular weight) The IR absorber from Example 1 in WO 2008/086931 having the structure below has similarly obtained a colorless offset print having excellent light resistance, which is clearly visible in the IR range when used infrared viewing device.

Excellent resistance to solvents such as ethanol, white spirit, acids, bases, hydrogen peroxide, artificial sweat and detergents has been shown. But resistance to solvents such as toluene, acetone, boiling water, or aggressive chemicals such as hypochlorite is not sufficient for printing banknotes.

The testing methodology is described in the chapter “Chemical and Physical Resistance” in “Extract of the ANNEX 13 of the Technical Specification for Euro banknote production” (European Central Bank; July 2004).

The table below shows the results of testing strategically important resistance parameters for Examples A3, A4 and the described comparative example.

Resistance to: Example A3 Example A4 Comparative Example Acetone four 3 2 Toluene four 3-4 2 Hypochlorite (5%) four 3-4 one Boiling water 3-4 3 1-2

Evaluation in an IR camera equipped with a filter with a transmission limit (715 nm)

Evaluation parameters according to the European Central Bank

4: no changes or slight changes invisible to the naked eye

3: small changes

2: significant changes; less than 50% damaged

1: big changes; damaged over 50% 0: item has disappeared

Example A5 (Laser welding of plastics)

Using a thermoplastic machine, the IR absorber from Example 1 was introduced into a polycarbonate disk 2 mm thick (concentration of 100 particles per million). Using an Nd: YAG laser, the resulting almost colorless disk was welded at a power of 30 W and a advance speed of 20 mm / s to a second disk of pure polycarbonate 1 mm thick that did not contain an IR absorber. The resulting weld is characterized by excellent strength, unchanged transparency, the absence of inclusions and bubbles. With a large mechanical load, there is no rupture of the disks along the weld.

Example A6 (Laser welding of plastics)

By the methods described in Example A5, but using an IR absorber from Example 5b, a substantially colorless polycarbonate disk having excellent weld characteristics was similarly obtained. The resulting weld has an unchanged transparency, welding does not give inclusions or bubbles, and the strength of the resulting weld is excellent.

Examples A7 and A8

By the methods described in Examples A5 and A6, but using instead of an Nd: YAG laser (1064 nm) a diode laser with a wavelength of 980 nm, good results were obtained similar to those described in Examples A5 and A6.

Examples A9 and A10

By the methods described in Examples A5 and A6, but using instead of an Nd: YAG laser (1064 nm) a diode laser with a wavelength of 940 nm, comparable good results were obtained with a laser power of 80 watts.

Example A11

By the methods described in Example A5, but using polypropylene discs with a thickness of 1.5 mm, welded structures with similar very good characteristics were obtained.

Claims (12)

1. The use of compounds selected from the group comprising compounds of formulas (1) to (19)

or mixtures thereof,
as colorless IR absorbers for printing with anti-counterfeiting. 2. The use according to claim 1, where the compound has the formula (1) or (19). 3. The use according to claim 1 or 2 for printing banknotes with anti-counterfeiting. 4. The use of a mixture containing at least one compound defined in claim 1 or 2, and at least one other infrared absorber other than the compounds defined in claim 1 or 2, for printing with anti-counterfeiting. 5. The use according to claim 4 for printing banknotes with anti-counterfeiting. 6. The use of the compounds defined in claim 1 or 2 in the composition of a printing ink for printing with anti-counterfeiting, to improve the resistance characteristics of the resulting print, in particular to increase resistance to chemicals, solvents and / or boiling water. 7. The use of a mixture of compounds defined in paragraph 4, in the composition of a printing ink for printing with anti-counterfeiting, to improve the resistance characteristics of the resulting print, in particular to increase resistance to chemicals, solvents and / or boiling water. 8. A security document containing a substrate and at least one compound as defined in claim 1 or 2, or a mixture of compounds as defined in claim 4. 9. A security document obtained in a printing process in which a printing ink composition is used comprising:
a) at least one compound as defined in claim 1 or 2, or a mixture of compounds as defined in claim 4,
b) a polymeric binder,
c) solvent
d) optionally at least one dye, and
e) optionally at least one additional additive. 10. The security document of claim 9, wherein the used ink composition comprises:
a) 0.0001-25 wt.% at least one compound defined in claim 1,
b) 5-74 wt.% at least one polymeric binder,
c) 1-94.9999 wt.% at least one solvent,
d) 0-25 wt.% at least one dye, and
e) 0-25 wt.% at least one additional additive, where the sum of components a) -e) is 100%. 11. The security document of claim 9, wherein the used ink composition comprises:
a) 0.0001-25 wt.% at least one of the compounds defined in claim 2,
b) 5-74 wt.% at least one polymeric binder,
c) 1-94.9999 wt.%. at least one solvent
d) 0-25 wt.%. at least one dye, and
e) 0-25 wt.% at least one additional additive,
where the sum of components a) -e) is 100%. 12. A secure document according to one of claims 8 to 11, selected from a banknote, passport, check, voucher, identity card or card for money transfer, stamp and excise stamp.