RU2725599C1 - Composite material for marking a material object - Google Patents

Abstract

FIELD: manufacturing technology.SUBSTANCE: invention relates to the technology of producing special materials used for marking information carriers, such as banknotes, excise and postage stamps, identification documents, securities, plastic cards, museum exhibits, and various material objects requiring authentication. Composite material consists of at least three components: a first inorganic compound with low adhesion to the material of the object, having given luminescent properties in wavelength range (400–2500) nm, second inorganic compound with low adhesion capacity to material of object and with refraction index lower than that of first inorganic compound, at least in wavelength range (200–2500) nm, a third material based on a chemical compound with high adhesion capacity to the base material of the marking.EFFECT: technical result achieved when implementing the developed composite material consists in ensuring reliable retention of material particles, both at the stage of marking of the carrier, and during its operation.9 cl, 2 dwg, 3 tbl

Description

The invention relates to the field of technology for obtaining special materials used for marking information carriers, such as banknotes, excise and postage stamps, identification documents, securities, plastic cards, museum exhibits, and various material objects requiring authentication.

From the existing level of technology it is known that one of the promising ways to solve the problem of creating secure marking is to use non-standard inorganic luminescent compounds with special properties derived from rare-earth metal ions (REM) in its composition. This is not least due to the fact that the effect of the glow of a substance under the influence of exciting radiation (luminescence) is conveniently used for non-destructive and / or non-contact authentication of protected objects, including operational and high-speed monitoring of objects. An important circumstance is that the luminescence phenomenon has many varieties - in particular, they distinguish between phosphorescence, electroluminescence, optical quenching, anti-Stokes, flash luminescence, and others. In addition, various features of the manifestation of these luminescence effects can significantly expand the functionality of the protective marking, and solve the important task of cutting off at the authentication stage all kinds of imitating substances and fakes.

The choice of fluorescent. compounds with rare-earth metals can be explained by the fact that, in contrast to organic substances, energy transfer between different ions in a multi-activator phosphor is complex and depends on its composition, structure and even technological features of obtaining its crystals. In this regard, these luminescent substances are especially attractive for creating special protective markings with non-standard optical and physical properties. It is also known that even very insignificant impurities and differences in the ratios of rare-earth ions in the composition of the crystal structure of luminescent substances can lead to fundamental changes in the spectral composition, kinetics of the acceleration / decay of its luminescence bands, and other parameters subject to instrumental identification. This, in turn, allows you to create a wide range of various unique protective markings that differ in their instrument properties.

From practical experience it is known that luminescent materials are used, as a rule, as fillers in the composition of paper, or as a pigment in printing inks. Obviously, this imposes certain, often very stringent technological limitations on them.

One of the main technical problems to be solved when trying to introduce certain specific pigments, which are solid crystalline non-wettable particles, into paper or printing inks, is the problem of their "retention" in the medium of the carrier material (in paper pulp, or in a binder for printing paints). As a rule, materials based on inorganic luminescent compounds, in comparison with organic pigments and dyes, are characterized by an average particle size of 1 to 50 μm, often have an irregular particle shape, have insufficient adhesion and poor wettability (insufficient oil absorption), high brittleness and high abrasivity . As a result, these materials are not technologically advanced both in the preparation of printing inks and in the process of pulp casting, they tend to be torn away from the carrier material intensively, which, on the one hand, leads to an insufficient concentration of the substance for its subsequent detection in the final product, and on the other hand, it spoils the printing and paper-making technological equipment, leading to premature wear.

Obviously, to solve these problems it is necessary to reduce the surface energy of solid crystalline particles of the target luminescent substance. It is known that for this purpose it is possible to apply special coatings and surfactants applied to solid particles and reduce their surface energy, increasing oil absorption and adhesive properties.

Unfortunately, for various reasons, in practice this is not always possible to achieve by simple technical and technological methods.

One of the most significant reasons preventing this from being applied to luminescent substances is the very strong influence of the optical and / or electrical properties of coatings on the luminescent properties of these special compounds.

Since luminescence absorbs radiation (or some other type of energy) by a substance, transforms energy, and emits induced radiation, then, as a result, incident, excited and (sometimes) stimulating radiation must freely reach the surface of the particle and, accordingly, leave it. For this reason, the choice of coating for the inorganic part cannot be arbitrary. In particular, a number of titanium dioxide or silicon oxide coatings, which are in demand in the art, can degrade the special lighting and / or electromagnetic properties of these pigments, for example, by blocking or radically changing the spectral composition of the exciting and / or photostimulating radiation (in particular, this is mentioned in one of the main prototype patents - RU 2449363, publ. 27.04.2012).

To provide good optical conditions for the propagation of luminescent, photostimulating, and exciting radiation in the composition of the labeling carrier material, it is proposed to use an additional optically transparent material with the property of an antireflection coating with respect to the target luminescent material in the composition. Such a material should predominantly envelop the particles of the target luminescent substance, and be completely optically transparent in the ranges of the excitation, emission and luminescence stimulation spectra. Moreover, it must necessarily have a refractive index less than the refractive index of the matrix material of the luminescent material. This is necessary to improve the conditions for the penetration of exciting radiation into the luminescent particle, and the subsequent escape of the reradiated luminescent radiation from the particle into the external medium. Otherwise, when the refractive index of the enveloping material is higher than that of the luminescent target material, due to the effects of internal reflection, the composite particle will mainly turn into a waveguide (fiber), and the luminescent radiation will not go out well, or, in the extreme case, it will not be able to to leave.

The prior art group of patents known are WO 8103507A1, WO 8103508A1, WO 8103509A1, WO 8103510A1 and WO 8103511A1 (GAO, 1981). This group of inventions proposes to use for determining the authenticity of protected products, such as banknotes, marking based on luminescent substances with rare-earth metals, which are studied mainly in the IR region of the optical spectrum, and to carry out authenticity measurements of excitation spectra, luminescence spectra, the ratio of the intensities of the spectral bands of luminescence, and kinetic parameters of the luminescence bands.

Known patents US 4387112A, US 4047033A, RU 2429272, RU 2401293, RU 2434926, RU 2516129, significantly expanding the range and spectral ranges of luminescent substances used to protect against falsification of valuable documents. The described solutions are based on the use of new types of luminescent inorganic compounds having either narrow-band luminescence, or anti-Stokes luminescence in the visible spectrum, or the property of reradiation in the near infrared spectrum, or phosphorescence, or a combination of all of the above.

A known solution RU 2379195, (published on January 20, 2010), disclosing a solution to the problem of speedy checking the authenticity of banknotes, and proposing to use in order to determine the authenticity of inorganic luminescent compounds with a given dependence of the ratios of the intensities of the spectral bands of luminescence on the intensity of the exciting study.

The known solution RU 2379192 (publ. 20.01.2010), which proposes to use for protective labeling a combination of inorganic luminescent substances with various properties, for example, photostimulated luminescence ("flash" phosphors) and phosphorescence, in combination with anti-Stokes phosphors.

The solution RU 2614980 (published on March 31, 2017) is known, based on the use of complex, combined effects on the studied luminescent material, which can significantly increase the selectivity of authenticity control, since it excludes the vast majority of known prototypes and simulators that do not have the required response to complex effects. The invention describes a valuable document with a marking based on a luminescent inorganic compound having luminescence of a given spectral composition in the near infrared range of the spectrum, which additionally has the property of changing the luminescence intensity without changing its spectral composition under the influence of stimulating radiation in the UV or visible spectral range (optical quenching, or UV modulation of luminescence).

A solution is known, disclosed in PCT / IB 2009/005227, (published on May 24, 2013), which describes a light printing ink with a ferromagnetic pigment having a shell. However, in this solution, the pigment shell, consisting of known materials, is used only to reduce the color of magnetic pigments based on iron oxides, widely known in the art, and does not play the role of a carrier of pigment particles in paper or paints due to increased adhesion (oil absorption) of the coating.

Also known is the solution RU 2607816 (published on 01.20.2017) describing a security feature with several components, the security feature comprising a luminescent component and a masking component. In this case, the masking component is introduced to complicate the decoding of the structure of the luminescent component according to the X-ray diffraction pattern. The disadvantages of the proposed method include the fact that the second component is not mechanically associated with the first component, and does not solve the problem of retaining the main target component in the composition of paper pulp or printing ink.

Closest to the proposed invention is a solution RU 2449363 (publ. 04/27/2012) which describes a luminescent substance built on the principle of "core-shell", and a relatively large particle of the phosphor is stuck due to the adhesive forces of nanoparticles with other, including luminescent, properties. The task of the shell is to distort the spectral properties of the luminescence of the core particle. At the same time, the invention does not pose and does not solve the problem of improving the luminescence and retention of luminescent particles in paper or ink.

The technical problem solved using the developed composition is to ensure the authenticity of the material object.

The technical result achieved by the implementation of the developed composite material is to ensure reliable retention of particles of the material, both at the stage of labeling the carrier, and during its operation.

To solve the specified technical result, it is proposed to use a composite material of the developed composition, which consists of at least three components:

- the first inorganic compound with low adhesive ability to the material of the object, having the desired luminescent properties in the wavelength range (400-2500) nm,

- the second inorganic compound with low adhesive ability to the material of the object, and with a refractive index lower than that of the first inorganic compound, at least at least in the wavelength range (200-2500) nm,

- the third material based on a chemical compound with high adhesive ability to the material of the base marking.

In some embodiments, the first and second inorganic compounds are adsorbed on the third material to ensure that the third material is retained in the ink composition during printing and / or in the pulp during the paper production process, wherein the mass ratio of the first and second inorganic compounds to the third material ranges from 1: 1 to 1:10.

Preferably, the first inorganic compound has the property of optical quenching of luminescence in the wavelength range (400-2500) nm when exposed to stimulating radiation in the wavelength range (200-2500) nm.

The first inorganic compound may correspond to an empirical formula of the form:

(Ln _1-X-2Y Me ^III _X Me ^II _Y Me ^IV _Y ) ₂ O ₂ S

or:

(Ln _1-X-2Y Me ^III _X Me ^II _Y Me ^IV _Y ) PO ₄

or:

(Ln _1-X-2Y Me ^III _X Me ^II _Y Me ^IV _Y ) ₂ O ₃

either solid solutions of all of the above,

Where:

Me ^II - element of the II group of the Periodic system (Mg, Ca, Zn, Sr);

Me ^III - an element of group III of the Periodic system from a number of lanthanides (Er, Yb, Tm, Nd, Ho, Eu, Pr, Tb, Dy);

Me ^IV - an element of group VI of the Periodic system (Ti, Si, Zr, Ge);

Ln is an element from the series Sc, Ga, Y, La, Gd, Lu;

0.01 X X 0 0.9;

0.001 Y Y 0 0.2;

X + 2Y≤1.

The composite material may contain an additional component, which is an inorganic luminescent compound based on rare-earth metal ions, characterized by anti-Stokes luminescence of green, red, orange, blue, or white color under the influence of IR radiation in the wavelength range (800-1600) nm.

Preferably, the average particle size of the components is from 0.1 μm to 50 μm.

Composite material can be introduced into the base and / or applied to one of the surfaces of a material object

The composite material is preferably made colorless, and indistinguishable on the surface and / or in the composition of the material object when observed in daylight.

As a material object, a banknote, an excise stamp, a postage stamp, a passport, a travel document, a driver’s license, an identity card, a security paper, a plastic card, a label, a payment document, a museum exhibit can be used.

The developed technical solution is illustrated by examples.

Example 1

Composite material for use in paint, consisting of three components, the composition of which is given in table 1.

The first inorganic compound is an inorganic compound having luminescence in the wavelength range (990-1020) nm, when excited by a source in the wavelength range (940-970) nm, with optical modulation of luminescence radiation without changing its spectral composition when exposed to stimulating radiation in the wavelength range of 360-400 nm, and is a solid solution of the 2nd kind with the following empirical chemical formula:

(Y _0,98 Yb _0.01 Ca _0,005 Ti _0.005) O ₂ S: (Y _0,98 Yb _{0 01} Ca _0.005 Ti _0.005) PO ₄

The composite material corresponding to table 1, and having an oil absorption of 20 g / 100 g, in the form of pigment particles with an average size of 5 μm is introduced into the printing ink, the composition of which is shown in table 2.

The ink is applied by offset printing on the surface of the banknote in the form of colorless markings of a rectangular shape.

In FIG. 2 shows the structure of a banknote consisting of a paper backing (FIG. 2, pos. 1), a paint layer (FIG. 2, pos. 5), and a composite material consisting of a first inorganic compound (FIG. 2, pos. 2), a third material (Fig. 2 pos. 4) and the second inorganic compound (Fig. 2 pos. 3).

Example 2

A composite material for use in paper, consisting of three components, the composition of which is given in table 3.

The first inorganic compound is an inorganic compound having luminescence in the wavelength range (1500-1550) nm, when excited by a source in the wavelength range (800-850) nm, with optical modulation of the luminescence radiation without changing its spectral composition when exposed to stimulating radiation in the wavelength range of 360-400 nm, and is a solid solution of the 2nd kind with the following empirical chemical formula:

(Y _0.68 Er _0.3 Ca _0.01 Ti _0.01 ) ₂ O ₂ S: (Y _0.68 Er _0.3 Ca _0.01 Ti _0.01 ) ₂ O ₃

The composite material corresponding to table 1, and having an oil absorption of 20 g / 100 g, in the form of pigment particles with an average size of 25 μm is introduced into the mass, in the composition of offset paper weighing 90 g square meter, consisting of 90% bleached cellulose fiber, 5% of the specified composition, and 5% dye

On offset paper with composite material, by printing, an excise stamp was made for marking alcohol products.

In FIG. 1 shows the structure of an excise stamp security paper consisting of a paper backing (FIG. 1, pos. 1), a first inorganic compound (FIG. 1, pos. 2), a second inorganic compound (FIG. 1, pos. 3) and a third material (FIG. . 1 item 4).

Claims (26)

1. Composite material for marking a material object, characterized in that it consists of at least three components: - the first inorganic compound with low adhesive ability to the material of the object, having the desired luminescent properties in the wavelength range (400-2500) nm, - the second inorganic compound with low adhesive ability to the material of the object and with a refractive index lower than that of the first inorganic compound, at least at least in the wavelength range (200-2500) nm, - the third material based on a chemical compound with high adhesive ability to the material of the base marking. 2. The composite material according to p. 1, characterized in that the first and second inorganic compounds are adsorbed on the third material with the retention of the third material in the composition of the printing ink during printing and / or in the paper pulp during paper production, and the mass ratio of the first and the second inorganic compounds with respect to the third material is from 1: 1 to 1:10. 3. The composite material according to claim 1, characterized in that the first inorganic compound has the property of optical quenching of luminescence in the wavelength range (400-2500) nm when exposed to stimulating radiation in the wavelength range (200-2500) nm. 4. The composite material according to claim 1, characterized in that the first inorganic compound corresponds to an empirical formula of the form: (Ln _1-X-2Y Me ^III _X Me ^II _Y Me ^IV _Y ) ₂ O ₂ S, or: (Ln _1-X-2Y Me ^III _X Me ^II _Y Me ^IV _Y ) PO ₄ , or: (Ln _1-X-2Y Me ^III _X Me ^II _Y Me ^IV _Y ) ₂ O ₃ , either solid solutions of all of the above, Where: Me ^II - element of the II group of the Periodic system (Mg, Ca, Zn, Sr); Me ^III - an element of group III of the Periodic system from a number of lanthanides (Er, Yb, Tm, Nd, Ho, Eu, Pr, Tb, Dy); Me ^IV - an element of group VI of the Periodic system (Ti, Si, Zr, Ge); Ln is an element from the series Sc, Ga, Y, La, Gd, Lu; 0.01 X X 0 0.9; 0.001 Y Y 0 0.2; X + 2Y≤1. 5. The composite material according to claim 1, characterized in that it contains an additional component, which is an inorganic luminescent compound based on rare earth ions, characterized by anti-Stokes luminescence of green, red, orange, blue or white color under the influence of infrared radiation in the length range waves (800-1600) nm. 6. The composite material according to claim 1, characterized in that the average particle size of the components is from 0.1 μm to 50 μm. 7. Composite material according to claim 1, characterized in that it is introduced into the base and / or applied to one of the surfaces of a material object. 8. The composite material according to claim 1, characterized in that it is made colorless and indistinguishable on the surface and / or as part of a material object when observed in daylight. 9. Composite material according to claim 1, characterized in that the banknote, excise stamp, postage stamp, passport, travel document, driver's license, identity card, security paper, plastic card, label, payment document, museum exhibit are used as a tangible object .

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